HomeMy WebLinkAboutResolution No. 2008-70RESOLUTION NO. R2008-70
A RESOLUTION ADOPTING A DESIGN CRITERIA MANUAL FOR
THE CITY OF FRIENDSWOOD, TEXAS; CONTAINING STANDARDS
FOR THE DESIGN, CONSTRUCTION AND INSTALLATION OF
PUBLIC INFRASTRUCTURE AND RELATED FACILITIES AND
IMPROVEMENTS WITHIN THE CITY; AND REPEALING CITY OF
FRIENDSWOOD RESOLUTION NO. R2006-24, PASSED AND
RESOLVED ON THE 11TH DAY OF SEPTEMBER 2006, AND ALL
OTHER RESOLUTIONS OR PARTS OF RESOLUTIONS
INCONSISTENT ON OR CONFLICT HEREWITH.
WHEREAS, the City Council has determined a need for the adoption of comprehensive
and concise standards covering the design, construction, and installation of public infrastructure
and related improvements within the City; and
WHEREAS, the City has determined that such improvement standards and requirements
should be, to the extent practicable, incorporated into a single document; and
WHEREAS, attached hereto is that certain City of Friendswood Community
Development Department "Design Criteria Manual", which document contains certain design,
construction and installation standards for public infrastructure and related improvements
incident to City construction projects and subdivision and other development within the City's
jurisdiction; now therefore
BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY OF FRIENDSWOOD,
TEXAS:
Section 1. The facts and matters set forth in the preamble of this Resolution are
hereby found to be true and correct.
Section 2. That certain City of Friendswood Community Development Department
"Design Criteria Manual", dated September 2008, a true and correct copy of which is attached
hereto and for all things made a part hereof, is hereby adopted. The standards and related
documents contained and referred to therein shall control and are hereby established as minimum
design, construction, and installation standards for certain public infrastructure and related
improvements within the City of Friendswood, Texas, for City projects and subdivision and other
related development. In the event of conflict between any provision of the Design Criteria
Manual and any ordinance of the City, or between any condition of plat or development approval
imposed by the City, the provisions of any such ordinance or term or condition of approval shall
control.
Section 3. The Director of Community Development shall maintain copies of such
Design Criteria Manual and related documents, which shall be made available, upon payment of
the reasonable costs of publication thereof, to any person requesting same. The Director is
further directed to periodically evaluate and review such standards and, when deemed necessary
and appropriate, recommend changes to City Council.
Section 4. City of Friendswood Resolution No. R2006-24, passed and resolved the
I lth day of September 2006, is hereby repealed. All other resolutions inconsistent or in conflict
herewith, are, to the extent of such inconsistency or conflict, hereby repealed.
PASSED, APPROVED AND RESOLVED on this 61h day of October, 2008.
4DaidJ. H. Smith
Mayor
ATTEST: FR�ENO
O*
V o
D loris McKenzie, TRMC
City Secretary i b
R2008-70 2
CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
DESIGN CRITERIA MANUAL
Interin
CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
Design Criteria Manual
Table of Contents
SECTION
I. Graphic Requirements
II. Wastewater Collection System Design Requirements
III. Water Line Distribution System Design Requirements
IV. Street Paving Design Requirements
V. Storm Drainage Design Requirements
VI. Site Development Requirements
VII. Modification Procedures
APPENDICES
A. Attachments
B. Figures
C. Parking Group Table
D. Qualified Tree List
City of Friendswood
Community Development Department
SECTION I
Design Criteria Manual
GRAPHIC and Design REQUIREMENTS
GRAPHIC and Design REQUIREMENTS
1.0 GENERAL
Should any portion of this Section conflict with any provisions of the Subdivision Ordinance or
Zoning Ordinance, the latter two (2) will govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
1.01 CHAPTER INCLUDES:
Graphic and Design requirements for construction drawings.
1.02 REFERENCES
City of Friendswood Standard Details, latest version. These can be purchased from Community
Development or downloaded from www.ci.friendswood.tx.us
1.03 DEFINITIONS
A. CADD (Computer Aided Drafting Design) - the preparation of documents utilizing
computer facilities for the production of drawings, plans, prints and other related
documents.
B. HCFCD — Harris County Flood Control District
C. GCCDD — Galveston County Consolidated Drainage District
1.04 DESIGN REQUIREMENTS
A. Provide a cover sheet for all projects involving three or more design drawings (excluding
standard detail sheets). Plan sheet numbers shall be shown on the cover sheet or area key
map. Include a vicinity map to identify project locations. Also provide approval block for
the Director of Public Works and the Director of Community Development with a note
stating that approval is valid for 1 year only from date of signatures.
B. Preliminary drawings shall be prepared on nominal 24 inch x 36 inch or 22 inch x 34 inch
overall paper stock.
C. Final drawings shall be india WE on mylar or produced by CADD on mylar. The engineer
shall also submit, at the time of plan approval, an electronic version of the CADD drawings
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Design Criteria Manual
GRAPHIC and Design REQUIREMENTS
on diskette or CD-ROM of the development showing all lot lines and associated lot
information, rights -of -way, easements, contours -lines, utilities, and all drainage and paving
improvements.
D. Details of special structures (not covered by approved standard drawings, such as stream or
gully crossings, special manholes, or junction boxes, etc.) shall be drawn with vertical and
horizontal scales equal to each other, and shown on a separate sheet (s) from the Standard
Detail sheets.
E. Each set of construction drawings shall contain paving and utility key drawings indexing
specific plan and profile sheets. Standard City detail drawings, where applicable, shall be
included. All sheets shall have standard title blocks, and be sequentially numbered. Where
applicable, show HCFCD or GCCDD key drawings and numbers.
F. Draw project overall layouts to a minimum scale of 1 inch = 100 feet and provide an index
G. Plan stationing must run from left to right, except for short streets or lines originating from
a major intersection. An index sheet shall be shown on the overall cover sheet.
H. A north arrow shall be shown on all sheets (except standard or special detail sheets) and
shall be oriented either toward the top or to the right. This requirement is waived under the
following conditions.
1. A storm sewer, wastewater sewer or primary outfall
ditch drainage facility.
2. Short sections of improvements fitted on a sheet that otherwise has the north
arrow correctly shown.
Stationing is intended to start from the cardinal points of the compass and
proceed in the direction of construction.
I. Standard scales permitted for plans and profiles of paving and utility construction drawings
are as follows:
1. Major thoroughfares, streets with esplanades over 400 feet in length, or special
intersections / situation
1 inch = 20 feet horizontal, 1 inch = 2 feet vertical
Minor or residential single-family streets.
1 inch = 20 feet horizontal, 1 inch = 2 feet vertical
1 inch = 40 feet horizontal, 1 inch = 4 feet vertical
1 inch = 50 feet horizontal, 1 inch = 5 feet vertical
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City of Friendswood Design Criteria Manual
Community Development Department GRAPHIC and Design REQUIREMENTS
Scales in Paragraph No. 2 above are minimum; larger scales may be used to
show details of construction.
J. Each sheet of the plan and profile shall have a benchmark elevation and description of the
benchmark, and a current flood zone determination statement. Also include the temporary
benchmark (TBM) with their elevation and coordinates.
K. The seal, date, and original signature of the Professional Engineer licensed by the State of
Texas and who is responsible for the drawings shall be required on each sheet developed by
the engineer. The engineer may use a stamped or embossed imprint for his/her seal;
however, the embossed imprint must be shaded such that it will reproduce on prints.
L. A copy of the final plat for new developments shall be included with the final drawings
when submitted for final approval.
M. If a roadway exists where drawings are being prepared to improve or construct new
pavement or a utility, label the existing roadway width, surface type, and thickness.
Pavement thickness shall be ascertained by coring with the core hole grout filled to protect
pavement prior to construction.
N. Show all streets and/or road alignment on drawings.
O. Develop drawings to accurate scale showing proposed pavement, typical cross sections,
details, lines and grade, and all existing topography within street right-of-way, and any
easement contiguous with the right-of-way. At the intersection, the cross street details shall
be shown at sufficient distance (20-foot minimum distance outside the primary roadway
right-of-way) in each direction along cross street for designing adequate street crossings or
transitions.
P. Match lines between plan and profile sheets shall not be placed or shown within cross street
intersections including cross street rights -of -way.
Q. Natural ground profiles shall be shown as follows:
For privately -funded projects, center line profiles are satisfactory except where a
difference of 0.50 feet or more exists from one right-of-way or easement line to
the other, in which case, dual profiles are required.
For City of Friendswood projects, provide natural ground profiles at each right-
of-way line. Easement profiles shall conform to R.1 below.
R. Basic plan and profile sheets shall contain the following information:
Identify all lot lines, property lines, easements, rights -of -way, and HCFCD or
GCCDD outfalls.
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Community Development Department GRAPHIC and Design REQUIREMENTS
2. Label each plan sheet as to street/easement widths, pavement widths, pavement
thickness where applicable, type of roadway materials, curbs, intersection radii,
curve data, stationing, existing utilities (type and location), and any other
pertinent feature affecting design.
3. Show all utility lines 4 inches in diameter or larger within the right-of-way or
construction easement in profile view. Show all utility lines, regardless of size,
in the plan view including fiber optic cables.
4. Graphically, show flow line elevations and direction of flow for all existing
ditches.
5. Label proposed top of curb elevations and grades, except at railroad crossings.
Center line elevation and grades are acceptable only for paving without curb -and -
gutters.
6. Curb return elevations and grades for turnouts shall be shown in profile.
7. The center line elevation at the property line of all existing driveways shall be
shown in profile.
8. Station all esplanade noses or the center line of all esplanade openings with
esplanade width shown - both existing and proposed.
9. The design of both roadways is required on all paving sections with an esplanade.
10. Station all PCs, PTs, radius returns, and grade change PIs in plan view. Station
all radius returns and grade change PIs in profile with their respective elevations.
S. Provide a pollution prevention plan with legend. See Site Development (Section VI) under
Design Requirements.
T. The Drainage Plan shall have a current FEMA flood zone determination statement.
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City of Friendswood
Community Development Department
SECTION II
Design Criteria Manual
WASTEWATER COLLECTION SYSTEM
WASTEWATER COLLECTION SYSTEM
DESIGN REQUIREMENTS
1.0 GENERAL
Should any portion of this Section conflict with the Subdivision Ordinance (Appendix B) or the
Zoning Ordinance (Appendix C), the latter two (2) shall govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
Sanitary sewers located on private property that are not in a dedicated easement, are
under the jurisdiction of the Plumbing Code, and will be addressed/reviewed by the
Building Official.
1.01 CHAPTER INCLUDES:
Criteria for the design of wastewater collection systems.
1.02 REFERENCES
A. Texas Commission on Environmental Quality (TCEQ)- "Design Criteria for Sewerage
Systems" - Texas Administration Code - Chapter 317 (current revision).
B. City of Friendswood Standard Details, latest version. These can be purchased from
Community Development or downloaded from www.ci.friendswood.tx.us
1.03 DEFINITIONS
Where used in these regulations, the following terms shall be construed to carry the meanings
given below:
A. Public Sanitary Sewer - A closed conduit which conveys wastewater flow and which is
located within the public right-of-way or dedicated public easement. A public sanitary
sewer (or public sewer system) is intended to serve more than one (1) "owner".
B. Private Sanitary Sewer - A closed conduit which conveys wastewater flow and is
constructed and maintained by a private entity (ies) (i.e., homeowner's association). Private
sanitary sewers may be located in areas such as a private street or common area, and are
subject to the design and construction requirements of the Plumbing Code and must
discharge to a public sanitary sewer.
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C. Sanitary Sewer Main - A sanitary sewer which receives the now from one or more lateral
sanitary sewers.
D. Lateral Sanitary Sewer - A sanitary sewer running laterally down a street, alley, or
easement, which receives only the flow from the abutting property.
E. Service Lead - A sanitary sewer which branches off a public sanitary sewer and extends to
the limits of the public right-of-way. It shall be construed as having reference to a public
sanitary sewer branching off from a main or lateral sanitary sewer to serve one or more
houses, single-family lots, or other types of small land tracts situated in the same block with
the said main or lateral sanitary sewer, but not directly adjacent thereto. Such a line shall
never exceed 150 feet in length. If the sanitary sewer is designed to serve more than two
houses, or the equivalent of two single-family residences along a street, a lateral sanitary
sewer as defined above shall be constructed.
F. Service Connection - A private sanitary sewer from a single source to the main or lateral
sanitary sewer in the street, alley, or easement adjacent thereto. Service connections are
covered by the Building code. It will be owned and maintained by the owner of the
property being served by said sanitary sewer.
G. Project Area - The area within the immediate vicinity of the public sanitary sewer to be
constructed. If, as an example, a public sanitary sewer were to be constructed within the
public right-of-way, the project area would extend 10 feet to either side of the public right-
of-way. If as an example, a public sanitary sewer is to be constructed within a dedicated
easement adjacent to the public right-of-way, the project area would extend 10 feet to either
side of the dedicated easement, depending upon the existing topographical elements, unless
impacted by a permanent structure (i.e.. telephone pole, trees, drainage ditches, etc.) If, as
an example, a public sanitary sewer is to be constructed within a side lot easement (if
approved by the City), the same criteria would apply as for a dedicated easement adjacent
to public right-of-way.
H. Stack - A riser pipe constructed on main or lateral sanitary sewers which are deeper than 6
feet, measured from finished grade at manhole to facilitate construction of service leads or
service connections.
I. Force Main - A pressure -rated conduit (i.e. ductile iron pipe, pressure -rated PVC, etc.) that
conveys wastewater from a pump station to a discharge point.
All references hereafter to sewer, public sewer, private sewer, sewer main, lateral sewer,
service lead, service connections, stack and force mains shall mean elements of a sanitary
sewer system.
1.04 DESIGN REQUIREMENTS
A. Drawings to be furnished:
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Before any main or lateral sewer is constructed and before a permit shall be issued for the
construction of same, plans and profiles of the proposed sewer shall be prepared and
submitted to the City for approval. On projects within the City limits, the tfffeing
reproducible drawings and CADD file shall become the property of the City and shall
remain on file in the City for the use of any person who may be interested in such
information.
B. Details to be shown on drawings:
The detailed plan view will show the exact location of public sewer lines in the street, alley
or easement with respect to the edge of the particular right-of-way, the survey base line,
and any nearby utilities, major landscaping, and other structures affecting construction.
C. Main and Lateral Sewers
1. Sewers in curved easements, easements defined by property lines and combined
easements containing other public utilities shall be shown both in detailed plan and
profile views.
2. The profile shall show other underground and surface utilities and facilities, both in
parallel and at crossings; the size, grade of the proposed line, the elevation of same to
hundreds of a foot at all manholes, changes of grade and dead -ends, and the proposed
finished grade over the sewer. It shall show the actual ground line as it exists prior to
construction of the sewer. Where proposed fill or cut is contemplated, the proposed
new ground line shall be shown as a separate line from the actual ground line. Type
of pipe and bedding shall comply with City of Friendswood Standard Specifications
and Standard Details.
Where public sewers are to be placed between existing pavement and the street right-
of-way (or interior easement line) or under existing pavement or shoulders of
pavement, show the existing ground line at both sides (or the closest side for sewers
near the edge) of the right-of-way or adjacent sewer easement.
D. Sewer mains -plan and profile required
Sanitary sewer layouts for single-family residential subdivisions should use a scale of
100 feet or less per inch. A scale of 200 feet per inch may be used provided the
following information is shown on the layout:
a. All easements containing or buffering sanitary sewers shall have points of size
change shown, and all manhole locations shall be shown.
b. The sewer alignment shall accurately reflect the relative location of the sewer
as shown on the detailed plan view.
c. All service leads that cross street pavement or serve adjacent property shall be
shown on the layout. The detail plans and profiles shall show the flow lines of
all service leads at the street or easement right-of-way.
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d. The number and size of the lots depicted on both the overall sewer layout sheet
and the individual plan and profile sheets shall match the number and size of
the lots depicted on the final plat after recordation.
e. On the overall sanitary sewer layout sheet the size and direction of flow for all
existing and proposed sewers shall be shown.
f. The location of the proposed sewer within either the public right-of-way, a
dedicated easement adjacent to the public right-of-way, or side lot easement (if
allowed by the City).
g. The overall sanitary sewer layout sheet shall show the area, in acres, which the
proposed sewer(s) is (are) designed to serve. A location map shall be included
that references the average proximity to nearby major thoroughfare and
boulevard streets. The scale of the location map shall be 1 inch = 2,000 feet or
less.
2. Commercial subdivision sanitary sewer layouts for large areas and with a scale of 400
feet or more per inch shall have an additional set of layouts at not more than 200 feet
per inch, with match lines and a small index map showing which portion of the overall
layout that each sheet's layout represents.
3. Acceptable horizontal scales for the detailed plan and profile views shall be 10 feet, 20
feet, 40 feet and not more than 50 feet maximum per inch. Horizontal scale for major
thoroughfares and boulevards shall be 1 inch = 20 feet or less.
4. Acceptable vertical scales for detailed profile views shall be 2 feet, 4 feet, and not more
than 5 feet maximum per inch unless otherwise approved. Vertical scale for major
thoroughfares and boulevards shall be 1 inch = 2 feet or less.
5.The plan view shall show, at a minimum, the following information for the project area:
6.
a. All topographical features;
b. Stationing for the proposed sewers;
c. All existing underground and overhead utilities (i.e. telephone, gas, power, etc.)
d. Any significant landscaping and/or other structures which might impact
construction and/or construction related activities;
e. The width and type of all existing and proposed easements;
f. All proposed service leads;
g. The limits of bore and/or tunnel;
h. Locations where pressure rated pipe is to be installed at water line crossings;
i. Drawings for single-family residential subdivisions shall show the proposed
location, by stations, of all service leads, service connections, and stacks. The
distance from the sewer or survey base line station to the nearest existing
manhole shall be shown in the plan view or on an additional sewer layout sheet
with a scale no more than 1 inch = 100 feet;
6. The profile view shall show, at a minimum, the following information for the project
area:
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WASTEWATER COLLECTION SYSTEM
a. Underground and/or surface utilities/facilities which are either parallel to the
proposed sewer or cross the proposed sewers;
b. The proposed sewer's diameter and grade for each manhole section;
c. The flow line elevation for all sanitary sewers at each manhole;
d. The rim elevation of all existing and proposed manholes;
e. The flow line elevation at each sheet "break" (i.e., from one sheet to another);
f. Type of pipe bedding/backfill shall be noted on each plan/profile sheet;
g. The finished grade for proposed and existing pavement where "fill" and/or
"cut" is proposed, the proposed new ground elevation line shall be shown as a
separate line from the existing ground elevation line;
h. The existing ground elevation line for the "near side" of the public right-of-way
where a sewer is to be placed between the edge of existing pavement and the
edge of the public right-of-way;
i. The existing ground elevation line at the centerline of the proposed sanitary
sewer where a sanitary sewer is to be placed within an existing easement.
Show any proposed and/or existing pavement.
j. The flow line elevation of all service leads where they cross the edge of the
public right-of-way or the dedicated easement adjacent to the public right-of-
way;
k. The limits of bore and/or tunnel;
1. Locations where pressure rated pipe is to be installed at water line crossings;
m. The location of special backfill and/or proposed stacks shall be identified by
"stations" indicated on the design plans.
n. The location of stacks shall be labeled with stations.
E. Service leads
1. Service leads shall be at the property line between two (2) adjoining lots, or as
directed by the City. A single 6 inch service lead located at the property line
between two (2) adjoining lots would serve two (2) single-family residences with a
wye placed at the end of the service lead. Do not extend the wye clean -outs beyond
the edge of either the public right-of-way or dedicated easement.
2. Any service lead extension of more than 50 feet parallel to the street right-of-way
shall be treated as a lateral sewer.
Service leads from developments with more than 17,500 gallons -per -day flow shall
discharge into a proposed or existing manhole. Where the flow line of the service is
30 inches or greater above the flow line of the manhole, provide a standard drop to
manhole.
a. Service leads shall be provided to serve each lot within a proposed development
inside the City limits.
b. Service leads shall be 6 inches in diameter (minimum). If the length of a service
lead exceeds 100 feet or the width of the public right-of-way by more than 20
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feet, the minimum diameter shall be 8 inches and a manhole shall be utilized for
connection to the public sewer.
c. Service leads with a diameter of 6 inches shall utilize "full body" fitting
(extruded or factory -fabricated) for connection to the proposed public sewer or
an approved saddle -type connector for connection to an existing public sewer.
d. Saddle -type connectors shall be installed with the "stub" oriented between the
"spring line" (3 o'clock and 9 o'clock positions) and 45 degrees from the "spring
line" ("1:30" and "10:30" positions). Tees (aka, "full body fittings") shall be
oriented in the same manner.
e. The service lead shall be designated to minimize the use of bends as site
conditions will permit.
f. Service leads exceeding the limits defined in 1.04.E.2. shall have a manhole at
each end; as well as, a plan/profile drawing for each right-of-way crossing. All,
or part, of these service leads which are located in a public right-of-way, alley or
dedicated sanitary sewer or public utility easement may be treated as a public
sewer, depending upon the location of the terminal manhole and any intermediate
manholes.
g. For all existing lots (which are not served in accordance with these guidelines)
that need a service lead, if the distance to the nearest existing sewer is less than
50 feet, the service lead falls under the jurisdiction of the Plumbing Code and the
Building Official.
F. General Requirements.
1. Sanitary sewers within the City of Friendswood's jurisdiction shall allow for orderly
expansion of the system and shall conform with the comprehensive water and sewer
plan for the City of Friendswood.
2. Sewers shall be sized based on the minimum requirements set out in this standard
and the standard wastewater flow rates as established by the City of Friendswood.
3. All sewers shall conform to the minimum requirements of the Texas Department of
Health, "Design Criteria for Sewerage Systems".
4. Sewers shall be separated from water lines by a minimum of 9 feet. Where the
minimum separation is not maintained, refer to Section 7 for allowable clearances.
Sewers crossing utilities other than water, a minimum of 6 inches of clearance must
be maintained.
The public sanitary sewer, as maintained by the City of Friendswood, shall be
defined as all sewers, including stacks and service leads, that serve more than one
sewer connection, that are located in public easements or street right-of-ways, and
that are installed in accordance with these Standards.
6. Sanitary lines greater than 6 feet deep shall require stacks to facilitate construction
of service leads or service connections. Stacks shall be shown on plans with station
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numbers. Place stacks and wyes or tees as shown. Where no stacks are shown, it is
the responsibility of the licensed plumber to place a City approved saddle for
connection to the line and the responsibility of the City Inspector to determine that
such saddle is water tight and properly installed.
7. Materials and construction shall conform to latest City of Friendswood
specifications with all amendments thereto, including standard leak test.
8. Unless noted otherwise, all public sewers and service leads shall be completely
embedded in cement -stabilized sand to 6 inches below the pipe, 12 inches above the
pipe and to 6 inches on each side. All such bedding shall be compacted to 95%
standard proctor density. The cross-section so described herein shall be termed the
"embedment zone."
9. Backfill all excavation areas/trenches under or within 12 inches of existing or
proposed pavement or shoulder of pavement with cement -stabilized sand from the
top of the pipe "embedment zone" to the bottom of the subgrade. Cement -stabilized
sand must develop 100-psi compression at 48 hours. Backfill shall be compacted to
95% standard proctor density.
10. The location of all special backfill and of proposed stacks shall be shown by stations
in the drawings.
11. Construction notes shall designate the kind and class of pipe with exceptions to the
construction notes to be shown on the plan and profile sheets.
12. Non -sanitary sewer easements or fee strips such as pipeline, power company,
drainage district, railroad, etc., are in and of themselves insufficient and
unacceptable to permit laying of sanitary sewers and/or force mains across or along
the underlying private property or restricted non -sanitary use type of public
property.
13. The final determination as to that portion of a street, alley, or easement to be
occupied by a proposed sewer rests with the Director of Community Development
and the Director of Public Works who will take into consideration existing, planned
and proposed facilities such as manholes, pavement, pipe/conduits, along with
existing trees, shrubs, or other unique surface conditions when arriving at a
decision.
14. Where an easement for a public sewer ends at a public right-of-way, the last
manhole shall be extended into the public right-of-way at a minimum of 2 feet
beyond the property line; or as close to the public right-of-way as possible due to
acceptable clearances required for other utilities (i.e., water line and storm sewers).
15. The drawings for the sewer shall show the location of any existing known pipe, duct
or other obstacles that might interfere with the construction of the sewer and call
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such to the attention of the City any known obstacles that might be encountered in
constructing the sewer in any location under consideration. The Professional
Engineer for the project, who shall be licensed by the State of Texas, shall
determine the existence of pipes, ducts and/or obstacles from a visual survey on the
ground plus research of all public records and private records when available.
16. All sanitary sewer mains shall be constructed utilizing pressure rate pipe, SDR 26,
unless specifically approved by Director of Community Development and the
Director of Public Works.
17. In new developments, sanitary sewer lines shall be centered in sanitary sewer line
easements.
G. Line Size
1. The minimum pipe diameter for a public sanitary sewer shall be 8 inches.
2. 4-inch service leads shall be confined to the limits of the lot which they serve and
shall serve only the equivalent of one single-family lot. No four (4) inch sewer shall
be laid in any street, alley, or right-of-way.
3. 6-inch service leads shall not serve more than the equivalent of two (2) single-
family lots or other types of small land tracts.
4. 4-inch and 6-inch service leads for single-family residential lots shall have a
minimum grade of 1.0 percent and 0.50 percent, respectively.
5. For commercial service leads such as street bores, submit a copy of the approved
plumbing drawings to establish the required size of the line. The minimum size lead
shall be 6 inches.
6. All main and lateral sewers shall end in manholes, except for special and/or unusual
situations and subject to specific approval by the Director of Community
Development and the Director of Public Works.
All sewer lines shall be laid at a size and depth to conform to designs permitting an
orderly expansion of the sewer system of the City and so as to avoid a duplication of
lines in the future.
8. The City shall be the final judge as to sizes and depths required and exceptions to
"lateral service leads" as previously defined.
H. Line Depth
The sewer should be laid with the top of the pipe a minimum of 3 feet below
finished grade or top of curb, whichever is lower.
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2. Sewer laid in street rights -of -way with curb -and -gutter paved streets shall have a
minimum cover of 4 feet from the top of the pipe to the top of the curb to anticipate
future sewer extension.
3. Sewers laid in street right-of-way with crowned roads and side ditches shall have a
minimum cover of 5 feet from the average ground elevation line at the adjacent
street right-of-way to the top of pipe.
4. Where the minimum cover as specified in paragraphs H, 1,2, and 3 above is not
possible, the sewer shall be laid in Class 150 (150 psi) pressure pipe or rigid factory
made pipe with cement -stabilized sand as shown on the City's Standard Details.
Ductile iron pipe shall be lined with either a polyethylene or polyurethane coating as
approved by the pipe manufacturer and applied by either the pipe manufacturer or
an approved application. The minimum liner thickness shall be 40 mils.
5. Maximum depth for 8 inch, 10 inch, and 12 inch collection lines shall be 20 feet
from average ground surface to pipe invert. Depths greater than 20 feet are subject
to approval by the City Engineer if justified for site -specific reasons during the
preliminary engineering phase of the project design.
Line Grades
The following table lists the minimum grades for 6 inch through 27 inch public
sewers. The minimum grade is based on a minimum full pipe velocity of 2.0 feet
per second. The maximum grade is based on a maximum full pipe velocity of 10.0
feet per second. In both cases, the Manning Formula has been used with an "n" of
0.013. The use of different pipe materials will not alter the use of 0.013 for the
purpose of the Design Manual.
Inside Dimension (I.D.)
of Pipe in Inches
6
8
10
12
15
18
21
24
27
Minimum Slope (in Percent)
to Develop V=2.3 ft./sec.
0.65
0.44
0.33
0.26
0.19
0.15
0.13
0.11
0.087
For sewers larger than 27 inches in diameter, the Professional Engineer of record,
who shall be licensed by the State of Texas, shall determine the appropriate grade
utilizing the Manning Formula, n = 0.013 and a full pipe velocity of 2.3 fps.
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J. Manholes
Design Criteria Manual
WASTEWATER COLLECTION SYSTEM
All manholes shall be precast concrete, unless the Professional Engineer of record
submits a "cast in place" manhole design for review and approval by the Director of
Community Development and the Director of Public Works. All precast manholes
to incorporate a "boot" type connector for sewer diameters up to 24 inches. For
sewer diameters greater than 24 inches, utilize either the "boot" type connector (if
available) or an integral gasket. All precast manholes shall conform to the latest
ASTM requirements. No manholes may be placed in the paved portion of the City
right-of-way.
For all public sewers, manholes shall be placed at all changes in alignment, changes
in grade, junction points, and either at street, alley, or easement intersections as
designs may require.
a. Sewers laid in easements shall have a manhole in each street crossed by the
sewer.
b. The maximum distance between manholes shall be 350 feet for 8 inch to 48 inch
pipes diameters. Spacing for lines of a diameter larger than 48 inches shall be
determined on an individual project basis.
c. Sewers with the same, or approximate flow line elevation shall intersect each
other at a 90-degree angle. However, where a true perpendicular intersection
cannot be obtained, and where the "entering" sewer intersects the receiving sewer
at, or about, the same flow line, one or more manholes shall be utilized to
maintain a minimum 80-degree angle at the point of intersection. When the
"entering" sewer is on the upstream side of the manhole, the minimum angle
between the sewers may be reduced to a 45-degree angle; provided:
(1) A distinct flow channel can be maintained within the manhole when the
flowline elevations of the sewers are at, or within, one (1) pipe diameter
of the smaller pipe; or
(2) When the flow line elevation of the "entering" pipe is above the crown of
the "primary" sewer and clearance can be provided between the sewers.
d. Manholes shall be placed at all dead-end mains and laterals.
e. Criteria for connections to, and utilization of, manholes.
(1) Where manholes are utilized to facilitate connections between public
sewers, when possible the sewers shall either match the manhole's flow
line, match the elevation of each other's crown or utilize an "outside"
manhole drop.
(2) Connections between public sewers at the manhole shall adhere to the
following criteria when possible:
(a) The elevation of the crown of the discharging sewer shall either
match the elevation of the crown of the receiving sewer or be
approved as special cases by the Director of Community
Development and the Director of Public Works.
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WASTEWATER COLLECTION SYSTEM
(b) A standard drop connection is required when the difference in
elevation between discharging sewer flowline and receiving
flowline is greater than 30 inches.
(3) The routing of service connection directly to manholes will be allowed
only where the flowline elevation of the existing sanitary sewer is more
than 10 feet below grade and there is no available stack, and either:
(a) The lot to be so connected is a single-family, owner -occupied,
single lot residence connection to an existing manhole; or
(b) The lot to be so connected is a single-family, owner- occupied,
single lot residence connecting to a proposed manhole at the end o
a cul-de-sac.
(4) When routing an approved service connection to a manhole (see Item
"3 "), the wall penetration shall not be greater than 10 inches in diameter
and shall be cored and sealed using grout as approved by the Standard
Wastewater Products Committee.
(5) When routing an approved service connection to a manhole (see Item
"3"), the connections shall utilize a "drop (either inside or outside) and
shall adhere to the following criteria:
(a) The manhole wall penetration shall be a minimum of 10 feet
below the manhole rim elevation and shall not be greater than 10
inches in diameter;
(b) The drop shall be 6 inches in diameter and shall be constructed of
SDR 26 PVC pipe (ATSM D 3034-94);
(c) The drop shall be located 45 degrees from the upstream side of
the main sewer;
(d) An internal drop shall be affixed to the manhole wall utilizing
stainless steel bands and anchor bolts.
(e) An internal drop shall terminate with a 45-degree bend. Said 45-
degree bend shall not extend below the "top of pipe" elevation of
receiving sanitary sewer and;
(f) The wall penetration (core) shall be sealed using a "grout" as
approved by the Director of Community Development and the
Director of Public Works.
(6) All public sewers shall terminate in a manhole. Clean -outs will not be
utilized except at the end of each service lead.
(a) The manhole cover shall have a minimum diameter of 32
inches.
(b) All sanitary sewer manholes shall have inflow protectors.
K. Lift Stations
Lift station design shall comply with the City of Friendswood specifications, with
a storage volume in the wet well equal to one and one-half (1.5) times the peak
design flow to the lift station. Add 10 percent to account for volume displaced by
pumps.
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2. A startup package for the pumps shall be submitted to the Director of Public Works
before final acceptance. This package should also include a completed start up log
sheet with field and product data. See Attachment 1.
3. Minimum site size shall be 40 feet by 40 feet. Smaller sites, that are adjacent to
public rights -of -way are contiguous to green space or similar land use areas, may be
approved when adequate odor control provisions are provided.
4. Pumps shall be sized to operate at optimum efficiency. Minimum acceptable
efficiency at the operating point will be 60 percent unless specifically approved by
the Director of Community Development and the Director of Public Works..
5. Operation and maintenance shall be considered in the design of the station and the
location of the station.
6. Wet well working volume shall be sized to allow for the recommended pump cycle
of 6 minutes for each pump.
7. Prior to installation, controls and equipment shall be approved by the Director of
Public Works.
8. Emergency operations shall be considered. Provide fittings and a blind flange that
will be readily accessible for emergency bypass pumping.
9. The inlet structure shall be designed to minimize turbulence.
10. The velocity in the force main and riser pipes shall be less than 8 feet per second
and greater than 3 feet per second.
11. The wet well shall be sized to provide adequate clearance between the pumps (refer
to manufacturers recommended clearances).
12. A peak factor of four (4) shall be used for lift station design.
13. A minimum of 2 feet of clearance shall be provided between pumps and between
pump and wall.
14. Low water levels shall be at least 6 inches above impeller, or higher if required by
manufacturer.
15. Complete immersion of submersible pump motor at low water level is preferred, if
possible.
16. Tie reinforcing steel in lift station bottom to wall reinforcing steel (includes caisson
construction situation) to provide watertight wetwell.
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WASTEWATER COLLECTION SYSTEM
17. Nuts, bolts, chains and all other metal components within wetwell shall be stainless
steel, not carbon steel.
18. Vent pipe shall be 8 inches minimum diameter equipped with odor control system.
19. The following Hazen -Williams Coefficient shall be used for various pipe types:
PVC New
C =
160
10-year
C =
140
DIP New
C
= 140
10-year
C =
100
20. Provide board fence (either cedar or heart redwood) with steel posts set in concrete.
Fence shall be at least 8 feet high.
21. Entrance drive to be at least 14 feet wide concrete pavement. Provide enough room
to park vehicles inside lift station site.
22. Indicate method of drainage of site on site plan. Internal drainage, sheet flow and
valley gutter driveways are acceptable. Drain to street or storm sewer, never onto
adjacent private property.
23. Locate control panel and wetwell hatch above 100-year flood plain. Call out the
100-year flood plain elevation on the plans.
24. Stainless steel guide rails (or other pump removal method that avoids entering
wetwell) are required for submersible pumps.
25. A tee, plug valve (or gate valve), and blind flange assembly is required on the force
main on the downstream side of the discharge valves and header. This is required so
truck -mounted pumps can bypass the lift station pumps and piping while
maintenance work is being done on lift station.
26. Bedding for PVC force main shall be cement -stabilized sand.
27. PVC force mains shall be AW WA C-900.
28. DIP force mains shall be bedded in bank sand and polyethylene wrapped.
29. When calculating headloss in force main and piping, use of K factors on fittings,
with the Hazen -Williams formula, is preferred.
30. Backfill structural excavations (wetwell, etc.) with cement -stabilized sand.
31. Lift station site plans shall be submitted in scales of 1-inch = 5-feet or 1-inch = 10-
feet.
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32. Provide a protective coating or concrete additive to interior walls of wetwell. The
Director of Public Works shall approve coating or additive used.
33. Lift station shall be equipped with a telemetry system, approved by the Director of
Public Works and shall be compatible with existing systems in the City. A bubbler
system shall be installed and connected to telemetry system to monitor status of lift
station.
34. Power supply to lift station shall be 3-phase (and 480 volts where possible).
35. A system of floats shall be provided to control pumps.
36. A pressure gauge suitable for application shall be installed on each discharge pipe.
37. A 1-inch minimum water service equipped with backflow prevention shall be
provided at the lift station site.
1.05 APPURTENANCES - Reserved
1.06 SUBMITTALS
A. Preliminary design - submit the following for review and comment:
1. Copies of any documents which grant approval of exceptions to the City's design
criteria.
2. Design calculations for line sizes and grades
3. Contour map for overall area.
4. Plan and profile sheets showing proposed improvements (City projects only).
5. Geotechnical soils report for the project (City projects only).
B. Final design - submit the following for approval:
1. Final documents of the above plus plan and profile sheets and Geotechnical soils
reports for non -City projects.
2. Review prints.
3. Original drawings.
1.07 QUALITY ASSURANCE
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A. Prepare calculations and construction drawings under the supervision of a Professional
Engineer licensed by the State of Texas and trained in the disciplines required by the
drawings. The final construction drawings must be sealed, signed, and dated by the
Professional Engineer responsible for the development of the drawings.
2.0 EXECUTION
2.01 RESEARCH REQUIREMENTS
A. Research existing utility and right-of-way information.
B. Verify that no restrictions exist that will deny approval of the project concept.
2.02 DESIGN ANALYSIS
A. Calculations of design flows for overall development project.
2.03 DRAWINGS
A. Drawings shall include layout sheets with contours, plan and profile sheets, and detail
sheets for special items and treatment plants.
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Community Development Department
SECTION III
Design Criteria Manual
WATER LINE DISTRIBUTION SYSTEM
WATER LINE DISTRIBUTION SYSTEM
DESIGN REQUIREMENTS
1.0 GENERAL
Should any portion of this Section conflict with the Subdivision Ordinance (Appendix B) or the
Zoning Ordinance (Appendix C), the latter two (2) shall govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
1.01 CHAPTER INCLUDES:
Criteria for the design of water lines
1.02 REFERENCES
A. Texas Commission on Environmental Quality (TCEQ), Water Utilities Division "Rules
and Regulations for Public Water Systems," latest revision.
B. American Water Works Association (AWWA).
C. National Sanitation Foundation (NSF).
D. Texas Department of Health.
E. Texas State Board of Insurance.
F. City of Friendswood Standard Details, latest version. These can be purchased from
Community Development or downloaded from www.ci.friendswood.tx.us
1.03 DEFINITIONS
A. Water Line - Closed conduits designed to distribute potable water for human consumption
to various areas and provide fire protection. Line size and fire protection accessory
locations are dependent on distance from primary source and quantity of demand.
1.04 DESIGN REQUIREMENTS
A. Easements for water lines.
Lines shall be located within street rights -of -way, permanent access easements with
overlapping public utility easements, easements adjacent to street rights -of way or
recorded water line easements.
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2. When outside of a public street right-of-way or permanent access easement with an
overlapping public utility easement, easements must be dedicated and restricted for
water lines only.
3. When possible, easements shall be contiguous with public rights -of -way.
4. Except for side lot easements, water line easements shall be contiguous to a paved
access.
5. For water lines 12 inches or smaller located outside of street rights -of -way, minimum
width of easement shall be 10 feet.
6. For water lines 14 inches or larger located outside of street rights -of -way, the
minimum width of easement shall be 15 feet.
7. For water mains located less than 5 feet from the right-of-way line, the outside edge
of a water line easement shall be located from the right-of-way line as follows:
12 inch and smaller pipe - 5 feet
14 inch and larger pipe - 10 feet
8. Water lines along State rights -of -way shall be installed outside of the right-of-way
whenever possible and in a separate 10-foot minimum contiguous easement.
9. No back lot easements shall be allowed for the installation of water lines, unless
specifically approved by the City.
10. Commercial developments inside the City requiring on -site fire hydrants must
provide a minimum 15-foot water line easement for the water line and fire hydrant.
11. In new developments, water lines shall be centered in water line easements.
12. When using side lot easements, such easements shall be a minimum of 10 feet in
width, located on one lot or centered between lots. If centered between lots, the
water line may be centered within the 5-foot easement on one lot, or centered in the
full 10-foot easement.
13. Location of water lines in an easement not adjoining a public right-of-way shall be
prohibited, except as specifically approved by the Director of Community
Development and the Director of Public Works. When approved, these water mains
will be centered in a 15-foot wide exclusive easement restricted to water only.
B. Location of water lines
Locate within a street right-of-way.
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WATER LINE DISTRIBUTION SYSTEM
2. Location of water lines within an easement - locate water lines in the center of a 10-
foot minimum width dedicated waterline easement. Within a commercial
development inside the City, center water lines within a 15-foot easement. Obtain
approval for lines to be located in wider or multi -use easements.
When a water line is placed parallel to another utility line, other than a sanitary
sewer, the water line shall have a minimum horizontal clearance of 9 feet from the
outside wall of the water line to the outside wall of the existing utility.
a). Where the nine foot separation distance cannot be achieved, the following criteria
shall apply: The new potable waterline shall be located at least two feet above the
new wastewater line, measured vertically and at least four feet away, measured
horizontally, from the replaced wastewater line.
4. When a water line crosses a sanitary sewer line, the vertical clearance shall be 9 feet
and the horizontal clearance shall be 4 feet.
C. Water line size
1. 6 inch lines may be used on dead-end lines within cul-de-sacs or if the line is less
than 1,000 feet in length and interconnected between two lines which are 8 inches in
size or larger. The maximum number of fire hydrants on any length of 6 inch line is
one (1).
2. 8 inch lines may be used for lines over 1,000 feet long or when two (2) or more fire
hydrants are required.
12 inch and larger lines — line length, usage, etc., to be determined by the
Professional Engineer of record, licensed by the State of Texas, and the Director of
Community Development and the Director of Public Works.
D. Dead-end lines
Dead-end lines within a public right-of-way.
a. On permanent dead-end lines, other than on cul-de-sacs, the line shall be 6
inches and shall not exceed more than 500 feet in length from the closest
interconnection main line and shall terminate with a fire hydrant.
b. On permanent dead-end lines on cul-de-sacs, reduce pipe size successively.
Carry 8 inch pipe to the next to last hydrant, then use 6 inch pipe to the line's
end. Place the last service as near as possible to the end and install a fire
hydrant at the end of the 6 inch line. The maximum length of this reduced line
size configuration shall not exceed 800 feet.
2. Dead-end lines with one on -site fire hydrant.
a. 6 inch lines may be used for lengths less than 200 feet provided domestic
service is taken from the end of the line.
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WATER LINE DISTRIBUTION SYSTEM
b. 8 inch lines may be used for lengths greater than 200 feet but less than 500 feet,
provided domestic service is taken from the end of the line.
E. Depth of cover
14 inch and smaller mains shall have a minimum cover of 4 feet from top of curb.
For open ditch roadway sections, lines 14 inches and smaller shall be installed at least
3 feet below the ultimate flowline of the ditch or 6 feet below natural ground at the
right-of-way line, whichever is deeper and maintain the elevation throughout the
project.
2. 16 inch and larger mains shall have minimum cover of 5 feet from top of curb. For
open ditch roadway sections, lines 16 inches and larger mains shall be installed at
least 3 feet below the flow line of the ditch or 7 feet below natural ground at the
right-of-way line, whichever is deeper and maintain the elevation throughout the
proj ect.
Changes in grade to clear other utilities or underground features may be made by
deflecting pipe joints. The maximum designed deflection shall be one-half ('/z) of the
manufactures allowable deflection. If a depth greater than 8 feet to the top of the
pipes is required, a welded steel section will be used. The standard depth of cover
maintained on the water main and the grade change shall be made using the welded
steel section. The installation of fittings for vertical deflections or changes in
elevation shall not be allowed except with specific approval by The Director of
Community Development and the Director of Public Works.
F. Water line crossings
Public and private utility crossings other than sanitary sewer.
a. Where a water line crosses another utility other than a sanitary sewer, a
minimum of 6 inches of clearance must be maintained between the outside wall
of the water line and the outside wall of the utility being crossed.
Stream and Ditch Crossings
a. Elevated Crossings
(1) All water lines shall be steel or restrained joint metallic pipe and shall
extend a minimum of 15 feet beyond the last bend or to the right-of-way
line, whichever is greater.
(2) Elevated crossings are preferred rather than underground crossings.
(3) Use a separate elevated supporting structure for 16 inch and larger water
lines unless otherwise approved by the Director of Community
Development and the Director of Public Works. Locate the structure a
minimum of 10 feet from any existing or proposed structure.
(4) Support water lines on existing or proposed bridges. The following
criteria may be used for 14 inch and smaller lines when approved in
advance by the Director of Community Development and the Director of
Public Works.
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(a) Have adequate structural capacity.
(b) Have sufficient clearance above the bent cap elevation for
installation under the bridge.
(5) Design elevated crossings with the elevation of the bottom of the water
line above the low chord of the nearest adjacent bridge or a minimum of
1 '/2 feet above the 100-year flood plain elevation, whichever is higher.
(6) Extend pipe from right-of-way to right-of-way for crossings.
(7) Provide sufficient span length to accommodate the cross section of future
widening of the stream or ditch, if available.
(8) Support the line on columns spaced to accommodate the structural
capacity of the pipe, considering deflection and loading.
(9) Base column support design on soil capacity, spacing, loading, and
structural requirements.
G. Underground crossings
Provide a minimum 3-foot clearance above the top of the pipe to the ultimate flow
line of the ditch.
2. Provide sufficient length to exceed the ultimate future development of the stream or
ditch.
3. All water lines shall be steel or restrained joint pipe and shall extend a minimum of
15 feet beyond the last bend or to the right-of-way, whichever is greater and have
valves located on both sides of the crossing.
H. TxDOT highway and county road crossings
Extend carrier pipe from right-of-way to right-of-way.
Use welded steel pipe or restrained joint pipe in steel casing under existing and future
roadways from a point 15 feet outside of the service road or outside of pavement
toward the right-of-way, to a similar point on the other side of the highway across the
right-of-way. For highway or roadway crossings with open ditch sections, extend the
casing from right-of-way to right-of-way.
3. Highway and county road crossings shall be constructed in conformance with the
requirements of the Texas Department of Transportation, Galveston County or Harris
County as applicable.
4. When additional right-of-way has been acquired or will be required for future
widening, the casing, where required, should be carried to within 10 feet of each
future right-of-way line.
Street crossings
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WATER LINE DISTRIBUTION SYSTEM
1. All water mains and sprinkler line crossings under major thoroughfare boulevards
shall be encased using a minimum of PVC pipe, SDR, as shown on the construction
detail for "Water Main Encasement." Welded steel pipe may be substituted on street
crossings, when specifically approved by the Director of Community Development
and the Director of Public Works.
2. Crossings under existing concrete streets, other than major thoroughfares, shall be
constructed by boring and jacking. PVC and SDR rated pipe shall be jacked into
place with equipment designed for that purpose. Water may be used to facilitate
boring and jacking operations. Jetting the pipe main into place shall not be
permitted. When conditions exist that warrant an open cut across of the existing
street, the Director of Community Development and the Director of Public Works
shall specifically approve the open cut crossing.
All open cut installations under existing or proposed streets shall be backfilled as
shown in the construction details.
All street crossings shall be constructed in accordance with construction plans
approved by the City. All street crossings shall be inspected by the Project Manager
and shall meet the requirements of these standards.
Oil and gas pipeline crossings
Do not use metallic pipe when crossing oil or gas transmission lines unless a properly
designed cathodic system is approved by the Director of Community Development
and the Director of Public Works, and is properly installed. Other pipe may be used,
regardless of depth, subject to approval by the Director of Community Development
and the Director of Public Works. Maintain a minimum 2-foot separation between
the pipeline and waterline.
K. On -site fire loops within commercial and multi -family developments.
For commercial and multi -family developments inside the City requiring on -site fire
hydrants, comply with the following requirements to allow maintenance and future
repair operations:
a. Do not allow placement of structures or equipment pads over the easement.
b. Provide 10 foot wide longitudinal pavement joint along easement lines where
the water line is located under a driveway, paved parking or street pavement.
L. Additional requirements
The carrier pipeline shall extend a minimum of 1 foot beyond the end of the casing to
allow flanged joints to be connected.
2. For welded steel bends, extend steel pipe a minimum of 5 feet beyond the bend.
M. Auger (bore) construction
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1. Use the following general criteria for establishing auger or bore sections:
a. Auger or bore sections shall be clearly shown on drawings.
b. Improved streets - use auger construction to cross the street regardless of
surface. Auger length shall be computed as roadway width at proposed bore
location plus 5 feet to either side of the roadway, where applicable.
C. Sidewalks - when the water line crosses under a sidewalk 4 feet or more in
width and in good condition, the sidewalk shall either be bored and jacked or
the sidewalk shall be removed and replaced to the City of Friendswood
Standard Details, whichever is most cost effective. Bore and jack length shall
be at least the width of the sidewalk. The proposed type of construction shall
be noted on the plans.
d. Bore Pits - Bore pits shall be at least 3 feet from back of curb and shall be at
least 5-feet from the back of curb on a boulevard or major thoroughfare. All
bore pits shall be shored in accordance with OSHA requirements. Bore pits
and/or receiving pits to be located in street or driveway paving shall be shown
on plans.
N. Water quality - overall system layout.
Circulation and flushing - The layout of the overall water distribution system shall
provide the maximum circulation of water to prevent future problems of odor, taste,
or color due to stagnant water.
a. Provide a source of fresh water at each end or at multiple points of a
subdivision. Provide ways to create circulation and place valves and fire
hydrants to allow simple flushing of all lines.
b. Avoid dead -ends whenever possible; when necessary, isolate dead -ends with a
line valve, keep as short as possible, and equip with a fire hydrant near the
line's end.
C. Where stubs are provided for future extensions, isolate the stubs with a valve
and do not allow service connections to stubs until extended. Place one full
pipe joint beyond the valve for stuff and plug end of pipes.
d. Water mains shall be looped unless physically impossible.
e. All materials which come in contact with public drinking water in any stage
shall conform with ANSI/NSF Standard 60. See Attachment 2.
f. Layout and size of all water mains shall be consistent with the overall layout
and phasing plan of the City's water system. The overall water system shall be
designed to maintain adequate pressure throughout the system.
g. In an unavoidable permanent dead-end situation, reduce the sizes of pipe
successively. Carry an 8-inch pipe to the next to last fire hydrant; use a 6 inch
PVC to the end of the line. Provide a fire hydrant at the end of the main.
O. Clearance of water line from other utilities. (New water lines constructed near sanitary
sewers and force mains).
1. New water lines parallel to sanitary sewers and force mains.
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a. Locate water lines a minimum of 9 feet horizontally, outside wall to outside wall,
when parallel to sanitary sewers or force mains. Use the following procedure
when 9 feet of separation cannot be achieved:
(1) When a new water line is to parallel an existing sanitary sewer force main
or gravity sanitary sewer and the 9 foot minimum separation distance
cannot be maintained, the existing sanitary sewer shall be replaced with
lined ductile iron or PVC pipe meeting ASTM specifications, having a
minimum working pressure rating of 150 psi or greater and equipped with
pressure type joints. The water lines and sanitary sewer shall be separated
by the design requirements of the TCEQ, and a minimum horizontal
distance of 4 feet, measured between the nearest outside walls of the pipe,
and in all cases, the water line shall be located above the sanitary sewer.
When a water main crosses a utility other than sanitary sewer, a minimum
of 6 inches of clearance must be maintained, and the water main shall have
one joint of pipe, a minimum 18 feet long, centered on the other utility.
b. Where a sanitary sewer crosses the water main, and that portion of the sanitary
sewer within 9 feet of the water is constructed as described in Section 290.44(e)
of the TCEQ Rules and Regulations, the water line may be placed no closer than
6 inches from the sewer. The separation distance must be measured between the
nearest outside pipe diameters. The water line shall be located at a higher
elevation than the sanitary sewer, wherever possible and one joint of the new
pipe, a minimum of 18 feet long, shall be centered on the existing line.
2. When water lines are installed in areas which have existing sanitary sewers, every
effort should be made to maintain 9 feet of separation between the outside pipe
diameters of the two lines. Where this separation cannot be achieved because of
local conditions, which must be fully documented in any planning material
submitted, the following spacings shall be observed:
a. Where a new water line is to cross or be installed in parallel with an existing
sanitary sewer, and the sanitary sewer is constructed as described in Section
290.44(e) of the TCEQ Rules and Regulations, the separation distances specified
in those rules shall apply as though the sanitary sewer was new.
b. Where a new water line is to be installed in parallel to an existing clay, truss, or
concrete gravity sanitary sewer showing no evidence of leakage vertically and
horizontally for a distance of 4 feet, the sanitary sewer need not be disturbed.
Should excavation for the water line produce evidence that the sanitary sewer is
leaking, then the sanitary sewer shall be repaired.
c. Where a new water line is to cross an existing clay, truss, or concrete gravity
sewer showing no evidence of leakage vertically or horizontally for a distance of
4 feet, the sewer need not be disturbed if the water line is to be installed at least
24 inches above the existing sanitary sewer. A full joint of the water line, at least
18 feet long, shall be centered over the sanitary sewer crossing, in this case, so as
to provide maximum protection against contamination.
d. Existing clay, truss or concrete sanitary sewer pipe which shows no evidence of
leakage and because of physical limitations shall remain at a higher elevation
Revised 9/2008 Section III Page 8 of 14
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WATER LINE DISTRIBUTION SYSTEM
than the proposed intersecting water line or closer than 2 feet of spacing may
remain undisturbed if the water line is inserted in a joint of pressure -type carrier
pipe at least 18 feet long and two (2) nominal sizes larger than the water line.
The carrier pipe shall be centered on the sanitary sewer crossing and both ends
sealed with cement grout. In lieu of this procedure, that portion of the sanitary
sewer within 9 feet of the water line may be replaced with cast iron or ductile
iron pipe with water -tight joints as described in Section 290.44(e) of the TCEQ
Rules and Regulations, above.
Sanitary sewer manholes - provide a minimum 9-foot horizontal clearance from
outside wall of existing or proposed sanitary sewer manholes unless manholes and
connecting sanitary sewers can be made water -tight and tested for no leakage. If a 9-
foot clearance cannot be obtained, the water line may be located closer to a manhole
when prior approval has been obtained from the Director of Community
Development and the Director of Public Works using one of the procedures below;
however, in no case shall the clearance be less than 4 feet:
a. A steel water line may be encased in a steel carrier pipe. Open cut and backfill
with compacted cement -stabilized sand.
b. The water line may be augured past the manhole with one 20-foot section of C-
900 PVC pipe 150 psi, installed centered about the existing sanitary sewer
manhole with pressure grout using a bentonite/clay mixture.
Fire hydrants. Do not install fire hydrants within 9 feet vertically or horizontally of
sanitary sewer mains, service leads, and force mains regardless of construction.
1.05 APPURTENANCES
A. Valves.
Set at maximum distances along line as follows:
a. 6 inch through 14 inch - 1000 feet.
b. 16 inch through 20 inch - 2000 feet.
C. The total number of valves at any intersection shall equal the total
number of lines leading out from the intersection point minus one, three
(3) valves for a cross, and two (2) valves for a tee, unless otherwise
specified.
B. Valve Types
1. Valve types (all valves shall open counterclockwise and have mechanical joints):
a. 6 inch through 14 inch — gate valves.
b. 16 inch through 20 inch — butterfly valves.
C. Location
All water lines shall be valved within the street right-of-way. Valves shall not be
placed under or within 2 feet of ultimate pavement, except as specifically approved
by the Director of Community Development and the Director of Public Works.
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2. Valves shall be located on the projection of intersecting street right -of- way lines or
at the curb return adjoining a paved street across the main. Tapping sleeves and
valves are excluded from this requirement.
3. Isolate fire hydrants from the service line with a valve located at the fire hydrant
branch. This valve shall not be located in the slope or flowline of ditches on open -
ditch streets.
4. Intermediate valves, not located on the projection line of the right-of-way line, shall
be located on lot lines or 5 feet from fire hydrants but not set in driveways or
sidewalks.
5. Locate valves a minimum of 9 feet horizontally from sanitary sewer crossings.
D. Fire hydrants.
Spacing.
a. Single Family Residential Development - 500 foot spacing.
b. Commercial, Multi -Family Developments and Multiple Single -Family
Dwellings - 300 foot spacing and at all street intersections.
Location in or along street right-of-ways.
a. Fire hydrants shall be located at street intersections where possible, but in any
case not more than than the spacing noted in la and lb.
b. Locate fire hydrants at P.C.s of the intersection curb radius, 3 feet behind the
existing curb or location of a future curb.
C. On all TxDOT highways, county roads and open -ditch streets, set the fire
hydrants within 3 feet of right-of-way lines. Fire hydrants lead valves shall not
be located in the slopes or flowlines of ditches.
d. Set intermediate fire hydrants on lot lines, extended to pavement, when located
between right-of-way intersections. These locations may be adjusted 5 feet
either way to miss driveways, sidewalks or other obstructions. In either case,
do not locate fire hydrants closer than 3 feet to curbed driveways or closer than
5 feet to non -curbed driveways.
e. Fire hydrants shall not be installed within 9 feet of a sanitary sewer system
under any condition.
Location of fire hydrants outside the street right-of-way.
a. The City Fire Marshal will establish and approve the location of fire hydrants
in apartment complexes and platted private street developments within the city.
b. Locate fire hydrants in protected, easily accessible areas behind curb lines.
C. For fire hydrants which are located adjacent to water lines constructed in 10-
foot wide waterline easements, the fire hydrant shall be centered in a minimum
10-foot by 10-foot separate easement.
d. For commercial and multi -family developments inside the city, provide
isolation valves at each end of fire loops requiring on -site fire hydrants.
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4. Fire Flow Requirements for Buildings
One (1) and two (2) family dwellings: The minimum fire flow requirements for one
(1) and two (2) family dwellings having a fire -flow calculation area which does not
exceed thirty-six hundred (3,600) square feet shall be one -thousand (1,000) gallons
per minute. Fire flow and flow duration for dwellings having a fire -flow calculation
area in excess of thirty-six hundred (3,600) square feet shall not be less that that
specified in Exhibit A -Table B 105.1 at the end of this section.
5. Fire hydrants should be audited for flow and pressure and painted per City
specifications.
E. Fittings
All fittings shall be identified and described on the construction plans.
Fittings are not permitted in fire hydrant leads, except as specifically approved by the
Director of Community Development and the Director of Public Works.
Normally, all water line fittings shall be mechanical joints only. Push -on joints may
be used at special locations if specifically approved by the Director of Community
Development and the Director of Public Works.
4. All plugs shall be provided with retention clamps.
5. Polyethylene tube encasement shall conform with the minimum requirements of
"Polyethylene Encasement for Gray and Ductile Cast -Iron Piping for Water and
Other Liquids", ANSI/AWWA C105, current revision. Soils within the project shall
be tested in accordance with Appendix A of ANSI/AWWA C105 to adequately
determine the requirements for encasement.
6. Concrete thrust blocking shall be required on all bends, tees, plugs and combinations
thereof.
7. All fittings and fire hydrants shall be tied together with 3/4-inch stainless steel all -
threads and I -bolts or approved equal (i.e., Mega Lugs).
F. Water main service
Water main service for lines in or along street right-of-ways.
a. Meters 2 inch and smaller - located in rights -of -way, water line easements, or
in a minimum 5'x5' separate water meter easement on private property. Meters
shall be located in areas with easy access and protected from traffic and
adjacent to right-of-way whenever possible.
b. Meters 3 inches and larger - located at the property line or in a minimum 10' x
20' separate water meter easement if necessary.
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(1) Meters shall be located in areas with easy access and protected from
traffic and adjacent to rights -of -ways whenever possible.
(2) Meters shall not be located in areas enclosed by fences.
C. Separate tap and service leads shall be designed for each meter.
d. Meters larger than 2 inches must have bypass assembly and coupling for easy
change out. Contact the Public Works Department for additional requirements.
For proposed apartments or town homes in private street developments, provide one
(1) master meter sized for the entire development. Exceptions may be granted by the
Director of Community Development and the Director of Public Works for unusual
circumstances. If an exception is approved, do not interconnect multiple meters.
All sprinkler and irrigation lines shall be eauitmed with a backflow prevention device
according to its application as reauired by current TCEO regulations. The backflow
assembly shall be located after the water meter for an irrigation system and in a vault
near the building for a sprinkler system. A certified tester shall test the backflow
prevention assembly annually and submit the results to the City.
1.06 SUBMITTALS
A. General - Conform to the following submittal requirements in addition to those of general
procedure of the City of Friendswood.
B. Water Line Sizes - Submit justification, calculations, and locations for proposed 6-inch
lines and for lines 12-inch and larger, for approval by the Director of Community
Development and the Director of Public Works, unless water line sizes are provided by
the City in advance.
C. Valves - Submit information for approval by the Director of Community Development
and the Director of Public Works with justification and locations for the use of 16-inch
and 20-inch gate valves proposed as substitutes for butterfly valves.
D. Water Meter Service
1. For construction inside the city limits, submit an application for meter services
and metered sprinkler connections to the Building Inspections Division prior to
construction.
2. Submit requests for more than one service meter in proposed private street or
multi -family developments to the Department of Public Works.
E. Elevated stream or ditch crossings - Submit design calculations for support columns and
column spacing.
F. Master Development Plan - For multiple -phase developments, submit a master
development plan along with construction plans.
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WATER LINE DISTRIBUTION SYSTEM
G. Backflow Prevention — All irrigation and sprinklers must be equipped with backflow
prevention devices per current TCEQ regulations.
1. A double check backflow prevention assembly is required for 3 inch and larger
lines.
1.07 QUALITY ASSURANCE
A. Prepare calculations and construction drawings under the supervision of a Professional
Engineer licensed by the State of Texas and trained in the disciplines required by the
drawings. The final construction drawings must be sealed, signed, and dated by the
Professional Engineer responsible for the development of the drawings.
2.0 EXECUTION
2.01 RESEARCH REQUIREMENTS
A. Research existing utility and right-of-way information.
B. Verify that no restrictions exist that will deny approval of the project concept.
2.02 DESIGN ANALYSIS
A. Water line sizes - Prepare narrative justification and calculations for proposed 6-inch
lines and for lines 12-inch and larger, unless sizing is provided by the City in advance.
B. Elevated stream or Ditch Crossings - Prepare design calculations for support columns and
column spacing.
2.03 DRAWINGS
A. General: Conform to the following drawing requirements in addition to those of
"Graphic Requirements" and the City's standard water line details and standard
specifications.
B. Appurtenances - Identify, describe and enclose in rectangular box on drawings.
Valves
a. Designate 6-inch through 12-inch gate valves with box as GV&B.
b. Provide complete description and size for other valves.
2. Water meters, service leads, and metered sprinkler connections.
a. Show the location of service line tees, tapping sleeve and valves, valve
boxes, and temporary plugs to be installed to serve future 3-inch or larger
meters.
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WATER LINE DISTRIBUTION SYSTEM
b. Develop plan and profile sheets for 4-inch and larger leads and connections
that cross public rights -of -way or other utilities.
C. Construction features
Show all special construction features required to complete the project, and in a
safe, convenient and economical manner.
Auger Construction
a. If the construction is predominately open cut, all portions of the street that
must be augured shall be clearly shown on drawings by location and length.
Include designation for sections at trees with 6 inches or larger diameters
located within 10 feet of water Line.
b. Curbs - Include a requirement on drawings for construction of ADA ramps at
street intersections where curbs are to be removed or are damaged by water
line construction. Conform to the City's Standard Details for ADA ramps.
Revised 9/2008 Section III Page 14 of 14
Exhibit A
Table B105.1
Minimum Required Fire Flow and Flow Duration for Buildingsa
Fire -Flow Calculation Area (square feet)
FIRE FLOW (gallons
per minute)°
FLOW DURATION
(hours)
IA and le
Type IIA and IIIAb
Type IV and V-Ab
Type IS and IIIBb
Type V-Bb
-Type
0-22,700
0-12,700
0-8,200
0-5,900
0-3,600
1,500
22,701-30,200
12,701-17,000
8,201-10,900
5,901-7,900
3,601-4,800
1,750
2
30,201-38,700
17,001-21,800
10,901-12,900
7,901-9,800
4,801-6,200
2,000
38,701-48,300
21,801-24,200
12,901-17,400
9,801-12,600
6,201-7,700
2,250
48,301-59,000
24,201-33,200
17,401-21,300
12,601-15,400
7,701-9,400
2,500
59,001-70,900
33,201-39,700
21,301-25,500
15,401-18,400
9,401-11,300
2,750
70,901-83,700
39,701-47,100
25,501-30,100
18,401-21,800
11,301-13,400
3,000
3
83,701-97,700
47,101-54,900
30,101-35,200
21,801-25,900
13,401-15,600
3,250
97,701-112,700
54,901-63,400
35,201-40,600
25,901-29,300
15,601-18,000
3,500
112,701-128,700
63,401-72,400
40,601-46,400
29,301-33,500
18,001-20,600
3,750
128,701-145,900
72,401-82,100
46,401-52,500
33,501-37,900
20,601-23,300
4,000
145,901-164,200
82,101-92,400
52,501-59,100
37,901-42,700
23,301-26,300
4,250
164,201-183,400
92,401-103,100
59,101-66,000
42,701-47,700
26,301-29,300
4,500
183,401-203,700
103,101-114,600
66,001-73,300
47,701-53,000
29,301-32,600
4,750
203,701-225,200
114,601-126,700
73,301-81,100
53,001-58,600
32,601-36,000
5,000
225,201-247,700
126,701-139,400
81,101-89,200
58,601-65,400
36,001-39,600
5,250
247,701-271,200
139,401-152,600
89,201-97,700
65,401-70,600
39,601-43,400
5,500
271,201-295,900
152,601-166,500
97,701-106,500
70,601-77,000
43,401-47,400
5,750
295,901-Greater
166,501-Greater
106,501-115,800
77,001-83,700
47,401-51,500
6,000
4
115,801-125,500
83,701-90,600
51,501-55,700
6,250
125,501-135,500
90,601-97,900
55,701-60,200
6,500
135,501-145,800
97,901-106,800
60,201-64,800
6,750
145,801-156,700
106,801-113,200
64,801-69,600
7,000
156,701-167,900
113,201-121,300
69,601-74,600
7,250
167,901-179,400
121,301-129,600
74,601-79,800
7,500
179,401-191,400
129,601-138,300
79,801-85,100
7,750
191,401-Greater
138,301-Greater
85,101-Greater
8,000
For SI: 1 square foot = 0.0929 m2, 1 gallon per minute = 3.785 Um, 1 pound per square inch = 6.895 KPA.
a. The minimum required fire flow shall be permitted to be reduced by 25 percent for Group R.
b. Types of construction are based on the Intemational Building Code.
c. Measured at 20 psi.
2003 INTERNATIONAL FIRE CODE®
City of Friendswood
Community Development Department
SECTION IV
STREET PAVING DESIGN REQUIREMENTS
Design Criteria Manual
STREET PAVING
1.0 GENERAL
Should any portion of this Section conflict with the Subdivision Ordinance (Appendix B) or the
Zoning Ordinance (Appendix C), the latter two (2) shall govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
1.01 CHAPTER INCLUDES:
Geometric design guidelines for streets, criteria for street paving, and standard paving notes for
drawing call outs.
1.02 REFERENCES
A. AASHTO - American Association of State Highway and Transportation Officials.
B. ASTM - American Society for Testing Materials.
C. ACI - American Concrete Institute.
D. TxMUTCD - Texas Manual on Uniform Traffic Control Devices.
E. City of Friendswood Standard Details, latest version. These can be purchased from
Community Development or downloaded from www.ci.friendswood.tx.us
1.03 DEFINITIONS
A. Geotechnical Engineer - An engineer certified by the American Association for Laboratory
Accreditation (A21,A).
B. HMAC - Hot Mix Asphaltic Concrete.
C. Curb -and -Gutter Streets — Full -width reinforced concrete pavement with curbs. Curb -and -
gutter streets require inlets and underground storm sewers.
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1.04
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STREET PAVING
D. Open -Ditch Streets — Full -width reinforced concrete pavement or asphaltic pavement with
open ditches. Open -ditch streets do not require underground storm sewers; however, the
ditches shall be designed to accommodate the storm water runoff.
DESIGN REQUIREMENTS
The following design requirements are applicable to all street pavement constructed within right-
of-way limits within the city limits of Friendswood.
A. General
1. All paving and construction plans for all streets within the city shall be approved by
the City of Friendswood.
2. Street design shall conform to all applicable planning tools, such as the Texas
Manual on Uniform Traffic Control Devices, major thoroughfare plans, master plans,
etc. Other considerations for design shall include street function, street capacity,
service levels, traffic safety, pedestrian safety, and utility locations. These additional
considerations may effect the minimum requirements set forth herein. Refer to the
City of Friendswood Major Thoroughfare Plan for streets requiring additional
considerations.
3. Designs shall conform to the City of Friendswood Standard Details.
4. Generally, the use of individual pavers is not allowed in the City of Friendswood
right-of-way; stamped concrete is allowed. The only exception for use of individual
pavers is for sidewalks in the Downtown District.
5. No asphalt turnouts are allowed in the City of Friendswood rights -of -way.
6. Concrete mix design shall conform to the City of Friendswood Design Specifications.
B. Minimum Width Requirements for Concrete Paving:
1. Curb -and -gutter concrete and HMAC streets for low -density residential
developments such as SFR, MFR-L and MFR-GHD: 28 feet back to back of curb
(B/B).
2. Pavement for open -ditch streets used for only SFR residential developments with
minimum 120-foot wide lots: 26 feet edge to edge of pavement.
3. Streets for medium to high density residential, commercial and collector streets: 41
feet BB of curb or from edge of pavement to edge of pavement.
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STREET PAVING
4. Streets for major thoroughfares or boulevards: two divided pavement sections of 25
B/B feet (4-lane divided) or two pavement sections 34 feet B/B of curb (6-lane
divided).
Radius for cul-de-sac pavement on any street shall be 50 feet, measured from the
face of curb. Radius of right-of-way for cul-de-sacs shall be 10 feet greater than the
cul-de-sac pavement, but not less than 60 feet.
C. Minimum Thickness and Reinforcement Requirements for Concrete and HMAC Pavement:
The following requirements shall be the minimum allowable. Pavement thickness and
reinforcement not less than the minimum requirements shall be designed by a Professional
Engineer, licensed by the State of Texas and who is responsible for the project, with the
design based on a current soils analysis and recommendations by a qualified geotechnical
engineer.
For pavement widths 28 feet BB of curb or 26 feet edge to edge of pavement:
a. Minimum concrete slab thickness shall be 6 inches with fc = 3,000 psi and
reinforcement shall be Grade 60, fy = 60,000 psi, #4 deformed reinforcing bars
spaced at 16 inches center to center both ways and minimum lap lengths of 18
inches. Expansion joints shall be placed at the end of each curb return and at a
maximum spacing of 60 feet with control joints every 15 feet.
b. Minimum stabilized subgrade thickness shall be 6 inches.
2. For pavement widths greater than 28 feet BB or 26 feet edge to edge of pavement,
and for boulevard or major thoroughfare sections:
a. Minimum concrete slab thickness shall be 7 inches with f,, = 3,000 psi and
reinforcement shall be Grade 60, fy = 60,000 psi, #4 deformed reinforcing bars
spaced at 16 inches center to center both ways and minimum lap lengths of 18 inches.
Expansion joints shall be placed at the end of each curb return and at a maximum
spacing of 60 feet on residential and collector streets, and a maximum spacing of 60
feet on boulevards and major thoroughfares, with control joints every 15 feet.
b. Minimum stabilized subgrade thickness shall be 8 inches.
D. Subgrade Treatment: The geotechnical engineer shall base depth of subgrade stabilization
on structural number (SN) in conjunction with pavement thickness design. The following
is a general guidance for subgrade treatment:
For subgrade soil conditions with a clay content of 10.0% or higher and plasticity
index (PI) of 10 or more, the subgrade shall be stabilized with lime. Subgrade shall
be stabilized with a minimum 6% lime by weight, at required thickness and
compacted to 95% standard Proctor density. Alternative subgrade stabilization may
be substituted when specific recommendations are made by the geotechnical engineer
for the project, and when specifically approved by the Director of Community
Development.
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STREET PAVING
2. For subgrade soil conditions containing a clean sand with no clay content, the
subgrade shall be stabilized with cement.
E. Requirements for Intersections, Turnouts, Transitions, and Boulevards or Thoroughfares:
l . At a "T" intersection with a street that has not been improved to its ultimate width,
the concrete pavement shall be stopped either at the right-of-way line or the end of
the curb return, whichever would require less concrete removal at a future date.
For roadway turnouts placed at an existing street intersection, the turnout shall be
designed to fit the ultimate pavement width of the intersecting cross street and then
transitioned to the existing roadway.
The transition length for meeting an open -ditch street shall be 50 feet for street
widths less than or equal to 28 feet B/B; 75 feet for 29 feet to 40 feet B/B width; and
100 feet for 41 feet BIB width or greater.
a. Streets other than concrete shall have transitions with a minimum thickness of
8 inches of lime stabilized subgrade, 6 inches of hot -mix asphaltic concrete
base, or approved equal, with 2 inches of hot -mix asphaltic surfacing.
b. Concrete streets shall have transitions with a minimum thickness of 6 inches of
stabilized subgrade and 6 inches of concrete pavement.
When paving only one section of a proposed two -section thoroughfare or boulevard
(boulevard section) all left -turn lanes and esplanade crossovers shall be paved to the
centerline of the street right-of-way.
F. Requirements for Ditches on Open -Ditch Streets:
1. Minimum grade on ditches shall be 0.20 percent.
2. Ditch capacity shall be designed to handle the storm water runoff as determined by
the City's Drainage Design Requirements.
3. The maximum side slope shall not be steeper than 3 horizontal to 1 vertical.
4. Culverts for roadside ditches only shall be designed to carry the storm water runoff,
but shall not be less than 18-inch diameter pipe constructed of reinforced concrete.
G. Requirements for Pavement on Curb -and -gutter Streets:
1. Inlet spacing:
a. Curb inlets shall be spaced and sized to intercept the calculated storm water
runoff for the design storm. The design water surface elevation for the design
storm flow at the inlet shall be less than or equal to the top of curb adjacent to
the inlet.
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b. Maximum travel distance of water in the street from a high point to a curb inlet
shall be 300 feet on major thoroughfares, boulevards, commercial streets and
collector streets unless otherwise approved by the Director of Community
Development. The maximum travel distance of water in the street from a high
point to a curb inlet permitted on residential streets shall be 300 feet unless
otherwise approved by the Director of Community Development.
C. Maximum drop of grade tangents from opposite directions to a common inlet
shall be 1.5 feet.
d. Curb inlets shall be located on the intersecting side street at an intersection with
a higher classification street. Location of curb inlets required on a major
thoroughfare at intersections shall be specifically approved by the Director of
Community Development.
e. Backfill around inlets below grade with 1.5 sacks per cubic yard of cement
stabilized sand and to top of first stage of inlets.
2. Design gutter grade shall be 0.30 percent; if the gutter grade is less than 0.30 percent
and approved by the Director of Community Development, then the Director of
Community Development shall determine the required inlet spacing. The minimum
acceptable gutter grade shall be 0.20 percent.
3. Maximum cut from finished grade at property line to top of curb shall be 1.75 feet.
4. Minimum grade shall be 1.0 percent fall around intersection turnout for a minimum
radius of 25 feet. Grades for larger radius shall be determined on an individual basis.
5. Vertical curves shall be installed when algebraic differences in intersecting grades
exceed 1.0 percent. Elevations shall be shown at 10-foot intervals through vertical
curves. Maintain a minimum of 0.03-foot elevation change at 10-foot intervals by
altering the calculated elevations.
6. When a curb -and -gutter intersects a drainage ditch, the elevation of the adjacent
gutter shall be above the design water surface elevation in the ditch.
7. Minimum gutter grade around a cul-de-sac shall be 0.60 percent.
8. Curves on major thoroughfares shall be superelevated in accordance with AASHTO
whenever the centerline radius of any lane of pavement is less than 2,000 feet.
9. The amount of cross slope over the pavement section shall be shown on the drawings.
The required cross slope shall be 3/8 inch per foot from curb line to quarter point, and
1/4-inch per foot from quarter point to the center line, and 7/8-inch per foot for left -
turn lanes.
10. A minimum grade of 0.40 percent around the longest radius is required on an L-Type
street intersection.
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Community Development Department
Design Criteria Manual
STREET PAVING
11. When meeting an existing upright curbed street, top of new curb elevations shall be
designed to meet an elevation 6 inches above the existing gutter/pavement, or gutters
shall be matched and new top of 6" curb transitioned to top of existing curb. At
existing inlets, top of new curb elevations shall be designed to match existing top of
existing inlets.
12. When the curb elevations are not established below the natural ground, fill lines shall
be shown on the drawings and shall be of sufficient height to ensure a minimum of
3/8-inch per foot transverse slope toward the curb from the property line between a
point, 2 feet outside the right-of-way and the top of curb. If this type fill is required
and the pavement is adjacent to a nonparticipating property owner, fill easements
from this property owner shall be obtained, filed, and a copy of the easements shall
accompany the final drawings. Construction of this nature will require back -slope
drainage design to prevent trapping storm water runoff.
13. Elevations and grades shall be labeled for all tops of curb. Centerline elevations and
grades are acceptable for open -ditch sections only.
H. Requirements for Inlets on Curb -and -gutter Streets:
1. Type "BB" with grate tops or type "H-2" inlets shall be used on all curb -and -gutter
streets within the City depending on storm water runoff requirements, unless
otherwise approved by the City.
2. Inlets shall be placed at the end of pavement in order to eliminate direct drainage of
storm water from the pavement gutter into an open -ditch or onto adjacent property.
On open -ditch streets, place stub -outs with ring grates from inlets to ditches.
I. Requirements for Curbs and Sidewalks:
1. For curbs located along the outside edges of residential streets, the standard
dimensions shall be 4-inches tall and 12-inches wide. Curb height for streets other
than residential shall be 6 inches tall. The curb height on all esplanades shall be 6
inches.
2. Sidewalks are required as set out in Section III of Appendix B-Subdivisions and
Section 70-66 of the Code of Ordinances, and where sidewalks are required, they
shall have a minimum width of 4 feet, except on TxDOT right-of-ways where the
minimum width shall be 5 feet.
Sidewalk wheelchair ramps shall be required at all intersections, and at or through all
driveways where required. The design and installation of such ramps shall comply
with Texas Accessibility Standards Architectural Barriers requirements.
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STREET PAVING
All sidewalks shall be constructed in accordance with the City of Friendswood
Standard Details, including through all driveways where required. The design and
installation of such sidewalks shall comply with Texas Accessibility Standards and
Architectural Barriers requirements.
5. The location of all proposed and existing sidewalks shall be shown on the
construction drawings.
Requirements for Miscellaneous Items:
1. The type and amount of subgrade treatment shall be shown on the drawings.
2. Paving headers shall be placed at the end of all concrete pavements.
3. All concrete to be removed shall be saw cut one half of the pavement depth before
removal.
4. Sight distance requirements shall be based on the latest version of the AASHTO
design practices.
5. Standard City of Friendswood barricades shall be placed at the end of all dead-end
streets not terminating in a cul-de-sac.
6. The appropriate drainage agency approval shall be obtained before City approval is
granted if the design involves a drainage way or other drainage facility.
7. A letter of agreement from the affected pipeline company(s) is required when any
paving is placed over a transmission pipeline or any storm sewer is placed over or
under such lines.
8. When new concrete pavement meets existing concrete pavement, horizontal dowels
shall be used if no exposed reinforcing steel for interconnection with new pavement
exists. Horizontal dowels shall be Grade 60, #6 rebars, 24 inches long, drilled and
embedded 12 inches into the center of the existing slab and epoxied. Dowels shall be
spaced at 16 inches center to center, unless otherwise specified.
9. Dead-end streets or ends of concrete slabs designed to be extended in the future shall
have paving headers and 12 inches of reinforcing steel exposed beyond the pavement,
coated with asphalt and wrapped with burlap, or shall have paving headers and dowel
type expansion joint for future pavement tie-in.
10. Pavement extensions shall connect to the existing pavement as shown on the City of
Friendswood Standard Details.
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Community Development Department STREET PAVING
11. A design for concrete pavement thickness is required for all pavement within
industrial areas and on major thoroughfares. Concrete pavement thickness design
shall be based on the latest version of the AASHTO design procedures for rigid
pavements.
12. The pavement structure for each roadway shall be designed based on soil data from
the site and based on the anticipated traffic volume, loading and service life of the
proposed pavement structure. The design engineer is responsible for ensuring that
the pavement structure is designed to withstand the anticipated loads on the roadway.
1.05 APPURTENANCES — Reserved
1.06 SUBMITTALS — Reserved
1.07 QUALITY ASSURANCE.
A. All construction drawings and specifications shall be prepared by or under the supervision
of a Professional Engineer licensed by the State of Texas, and all documents shall be
sealed, dated, and signed by the engineer responsible for their preparation.
B. All geotechnical testing, environmental and similar services for design and testing shall be
performed by or under the supervision of a Professional Engineer licensed by the State of
Texas and trained in the science of soil analysis. All design and testing reports and
documents shall be sealed, dated, and signed by the engineer responsible for their
preparation.
2.0 EXECUTION
2.01 RESEARCH REQUIREMENTS — Reserved
2.02 DESIGN ANALYSIS
A. All pavement design shall be supported by calculations to establish the required thickness
and reinforcement.
B. The appropriate geotechnical soils report shall be the basis for design considering the use,
loading, and life span of the proposed pavement.
C. All drainage improvements shall be designed to accommodate the anticipated storm runoff.
2.03 DRAWINGS
A. Construction drawings shall be prepared in compliance with the City of Friendswood
Design Criteria Manual, Section One- Graphic Requirements.
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Community Development Department
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STREET PAVING
B. Refer to The City of Friendswood Design Criteria Manual, Appendix B, Figure 1
"Geometric Street Design Standards" for additional information and guidance.
Revised 9/2008 Section IV Page 9 of 9
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Community Development Department STORM DRAINAGE
SECTION V
STORM DRAINAGE DESIGN REQUIREMENTS
1.0 GENERAL
Should any portion of this Section conflict with any provisions of the Subdivision Ordinance, of
Zoning Ordinance, the Galveston County Consolidated Drainage District or the Harris County
Flood Control District the latter four (4) will govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
1.01 CHAPTER INCLUDES:
Criteria for the design of storm drainage improvements.
A. Design requirements - The drainage criteria developed by the City of Friendswood and
complemented by those of the Galveston County Consolidated Drainage District and the
Harris County Flood Control District is intended to provide design guidelines for protection
of all areas of the City from structural flooding resulting from a 100-year storm event. This is
accomplished with the application of various drainage enhancements such as storm sewers,
roadside ditches, open channels, detention and sheet flow runoff. The combined system is
intended to prevent structural flooding from extreme events up to a 100-year storm; all
development must account for the 100-year storm event as further detailed in this Section.
B. Storm Sewer - Storm sewers and roadside ditch conduits are designed as a balance of
capacity and economics. These conduits are designed to convey less intense, more frequent
rainfalls with the intent of allowing for traffic movement on streets during these events.
C. Street Drainage — When rainfall events exceed the capacity of storm sewer system, the
additional run-off is intended to be stored, detained or conveyed overland in a manner that
reduces the threat of flooding to structures. Street ponding of short duration is anticipated
and designed to contribute to the overall capability of the drainage system.
D. Flood Control - The City of Friendswood is a participant in the National Flood Insurance
Program. The intent of the flood insurance program is to make insurance available at a
reasonable cost by providing for measures that may reduce the likelihood of structural
flooding.
E. Relationship to the Platting Process - Approval and review of storm drainage is a part of the
review process for planning and platting of new developments. The review of storm drainage
is overseen by the Community Development Department.
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Community Development Department STORM DRAINAGE
F. Acceptance Procedures — For projects in Galveston County, the Galveston County
Consolidated Drainage District must accept and approve all detention ponds or other drainage
facilities entering their system before the City of Friendswood accepts the infrastructure. For
projects in Harris County, the Harris County Flood Control District will accept and approve
all detention ponds as applicable.
1.02 REFERENCES
A. City of Friendswood Standard Details and Technical Specifications, latest version. These
can be purchased from the Community Development or downloaded from
www.ci.friendswood.tx.us
B. City of Friendswood Flood Damage Prevention Ordinance, Chapter 34 of the Code of
Ordinances, and any subsequent revisions.
C. Galveston County Consolidated Drainage District Criteria Manual
D. Harris County Flood Control District Design Criteria Manual. Ordinance No. T2007-20
amends the Flood Damage Prevention Ordinance by adopting the Harris County floodplain
maps as revised on June 18, 2007.
E. TX DOT Bridge Division Hydraulic Manual, the latest edition.
F. National Weather Service Documents - TP-40 Rainfall Frequency Atlas of the United
States.
G. Harris County/City of Friendswood Memorandum of Understanding regarding maintenance
of Harris County Hydraulic and Hydrologic models.
1.03 DEFINITIONS
Conduit - any open or closed device for conveying storm water.
Development - A change in land use that alters the impervious coverage of the tract of land.
Impervious cover includes, but is not limited to concrete, asphalt, stabilized soil, tennis courts,
water features, pools, sidewalks, crushed concrete, eAd limestone and roofing.
Drainage Area Map - Area map of a watershed which is subdivided to show each area served by
each subsystem.
FEMA - Federal Emergency Management Agency
GCCDD- Galveston County Consolidated Drainage District
HCFCD - Harris County Flood Control District
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Community Development Department STORM DRAINAGE
Hydraulic Grade Line - A line representing the pressure head available at any given point within
the drainage system.
In -Fill Development - Development of open tracts of land in areas where the storm drainage
infrastructure is already in place and takes advantage of the existing infrastructure as a drainage
outlet.
Public storm sewers - Defined as sewers and appurtenances that provide drainage for public
rights -of -way, or more than one private tract, and are located in public rights -of -way or drainage
easements.
Private storm sewers — Defined as sewers and appurtenances that provide drainage for a private
development, not normally available to the public.
Rainfall frequency- Probability of a rainfall event defined by a percent chance of occurring in any
given year. Information on rainfall frequency is published by the National Weather Service. For
the purpose of storm drainage design, the following frequencies are applicable:
1. 5-year frequency — a rainfall intensity having a 20 percent probability of occurrence
in any given year, or nominally likely to occur once every 5 years.
2. 10-year frequency — a rainfall intensity having a 10 percent probability of occurrence
in any given year, or nominally likely to occur once every 10 years.
3. 25-year frequency — a rainfall intensity having a 4 percent probability of occurrence
in any given year, or nominally likely to occur every 25 years.
4. 100-year frequency - a rainfall intensity having a 1 percent probability of occurrence
in any given year, or nominally likely to occur every 100 years.
Sheet Flow - Overland stormwater run-off that is not conveyed in a defined conduit.
1.04 DESIGN REQUIREMENTS
All designs of drainage facilities shall meet the requirements of the City of Friendswood Standard
Details and Technical Specifications.
A. Determination of Run-off
1. Design Storm Events - All drainage improvements shall be designed for the
following storm frequencies as established by the City of Friendswood, Galveston
County Consolidated Drainage District and The Harris County Flood Control
District.
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Community Development Department STORM DRAINAGE
Tyne of Facility
Frequency
Road Side Ditch 5 years
Storm Sewers 5 years
Channels/Storm Sewers/Culverts draining 100 acres or less 25 years
Bridges 100 years
Creeks/Channels/Culverts draining 100 acres or more 100 years
2. The Rational Method shall be used for determining the peak flow rate in the sizing of
all drainage improvements.
a. Time of Concentration (minutes) is the time required for peak runoff from the
entire upstream contributing area to reach the point of interest. Time of
concentration can be calculated based upon an analysis of the actual travel time
from the most remote point in the drainage area. The travel path should be
clearly denoted and a sketch included in the design calculations.
tc = D/60V + 10 (minutes)
D = flow distance (ft)
V = flow velocity (ft/sec)
For purposes of calculating tc, the following velocities are recommended:
V = 1 ft/sec for overland flow
V = 1.5 ft/sec or flow across paved surfaces or along gutter flowlines.
V = 2 ft/sec for flow in ditch or channel
V = 3 ft/sec for flow in storm sewer
b. Rainfall Intensity (inches/hour) shall be calculated using the following formula:
I = b
(d + tc)e
Values typically used in Friendswood are listed below:
Rainfall
tc <=60 min Frequency
b
d
e
5-year
92.9
19.7
0.788
10-year
107.9
23.6
0.781
25-year
98.5
24.0
0.729
100-year
90.8
16.5
0.685
Rainfall
t, >60 min Frequency
b
d
e
5-year
70.1
7.7
0.752
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Community Development Department STORM DRAINAGE
10-year 96.6 17.2 0.770
25-year 89.2 10.4 0.736
100-year 84.0 11.0 0.679
b, d, and a values are derived from a single frequency rainfall intensity graph.
b = the y-intercept of the straight line
d = a constant used to adjust the relationship to plot as a straight line
e = the slope of the straight line
c. The Rational Method is a method for calculating the peak run-off for a storm
drain system. The formula for determining the peak flow rate is:
Q = Cf CIA
Where:
Q = Flow rate (cubic feet per second (cfs))
Cf = Frequency factor, the product of Cf and C should not exceed 1.0
C = Runoff Coefficient
I = Rainfall intensity (inches/hour) for a given storm frequency
(Typically 5 year, 25 year and 100 year).
A = Area (acres)
For the purposes of peak flow calculations, use the following "Cf'
Cf = 1.00, for storm frequencies of 10 years or less
Cf = 1.10, for storm frequencies of 25 years
Cf = 1.25, for storm frequencies of 100 years
For the purposes of peak flow calculations, use the following "C" which are in
no way related to the lot coverage percentage as defined in the Zoning
Ordinance.
Land Use Type
Raw Undeveloped Acres
Improved Undeveloped Acres
(i.e. mowed, filled, re -graded, etc.)
Park Land
Residential:
SFR-Estates
SFR
Multi -family
MFR-GHD
MFR-L
Run-off Coefficient
0.20
0.30
0.40
0.45
0.60
0.65
0.75
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Community Development Department
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STORM DRAINAGE
MFR-M 0.80
MFR-H 0.85
MHR 0.85
Commercial/Industrial
OPDBP 0.90
OBD/CSC/NC 0.95
LI/I 0.95
Pond (detention and amenity) 1.00
Alternatively, for estate -sized lots (greater than 2.0 acres), the run-off coefficient "C"
in the Rational Method formula can be calculated from the equation:
C = 0.6Ia + 0.2
Where: C = watershed coefficient
Ia = impervious area/total area
If the alternate form is to be submitted, the calculation of "C" shall be provided as
part of the drainage calculations.
B. Design of storm sewers
1. Design Frequency
a. Areas of New Development
The design storm event for sizing storm sewers for new development areas
shall be a 5-year storm. In any case where new development interferes with the
natural sheet flow of the existing adjacent land, the storm system shall
accommodate the runoff. Stubbed -out streets next to undeveloped areas shall
have storm sewer lines continuing to an approved outfall.
b. In -fill Development
An existing storm sewer and structures shall be evaluated using a 5-year storm,
assuming no development takes place. The storm sewer and structures shall
then be evaluated with the development in place.
(1) If the proposed development has a lower or equal impervious cover, no
modifications to the existing storm sewer system are required.
(2) if the hydraulic gradient of the existing storm drain is below the top of
the curb, no improvements to the existing storm sewer system are
required.
C. Private Drainage Systems
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Community Development Department STORM DRAINAGE
Storm sewers for private drainage systems shall conform to the City of
Friendswood Standards for public drainage systems. Minimum diameter pipe
for a private storm sewer system is 10 inches.
(1) Unless otherwise approved by the Director of Community Development,
all private drainage systems shall be constructed in conformance with the
public storm sewer standards.
(2) An approved permit shall be fled with the City before any work shall be
done on a private drainage system, and shall include plan and profile
sheets detailing the scope of the work, including elevations.
(3) Open ditch areas may be converted into storm sewer lines with the
approval of a development permit. Guidelines for the process are
available at the City of Friendswood Community Development
Department.
(4) Private storm sewer connections to public storm sewers shall occur at a
manhole or at the back of an inlet as approved by the City.
Pipe Velocity and Slope Design
a. All storm drains shall be designed by the application of Manning's Equation and
the Continuity Equation.
Manning's Equation:
V = (1.486/n) Rv3S'/'
Where V = velocity (ft/sec)
R = hydraulic radius (area in square feet/wetted perimeter in feet)
S = slope of energy line in feet/feet (same as conduit bottom slopes for
uniform flow)
n = coefficient of roughness
n = 0.013 for concrete pipes,
n = 0.024 for CMP
n=0.011 for PVC
n = 0.010 for HDPE
*Note: All public storm sewers in or on public rights -of -way or public drainage easements shall be
constructed of RCP unless otherwise approved by the Director of Community Development.
Manning's roughness coefficients for CMP, PVC, and HDPE shall be used for storm sewers on
private property only. CMP pipes shall be used for public storm sewers only upon specific
approval of the Director of Community Development and/or the applicable drainage district
entity (GCCDD or HCFCD).
Continuity Equation:
Q=VA
Where Q = discharge (cfs)
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Community Development Department STORM DRAINAGE
V = velocity (ft/sec)
A = wetted cross sectional area of conduit (AZ )
b. Design velocities shall be 3 feet per second with the pipe flowing full.
C. Maximum velocities shall not exceed 7 feet per second without the approval of
the Director of Community Development.
d. Minimum Public Storm Sewer Pipe Slopes:
Pipe Diameter
% Slope
18
0.26 (18" used for inlet leads only)
24
0.18
30
0.14
36
0.11
42
0.08
48
0.07
54
0.06
60
0.05
For pipe sizes not listed above, the minimum slope shall be determined
utilizing a design velocity of 3 feet per second.
Pipe Sizes and Placement
a. Public storm sewer lines and inlet leads shall be a minimum of 24" inside
diameter and 18" inside diameter, respectively, or equivalent. Box culverts
shall be at least 2 feet x 2 feet inside dimension.
b. Larger pipes upstream shall not flow into smaller pipes unless it is intended for
detention requirements.
C. Match crowns of pipe at any size change unless severe depth constraints
prohibit such or engineering calculations show flowlines should be matched.
d. Locate public storm sewers in public street rights -of -way or in parallel and
adjoining easements or in other approved easements. Easements shall be at
least 20-feet wide and the storm sewer shall be centered in the easement.
Starting Water Surface and Hydraulic Gradient
a. The hydraulic gradient shall be calculated assuming the top of the outfall pipe
as the starting water surface.
b. At drops in pipe flowline, should the upstream pipe be higher than the
hydraulic grade line, then the hydraulic grade line shall be recalculated
assuming the starting water surface to be at the tope of pipe at that point.
C. For the design storm, the hydraulic gradient shall at all times be below the
gutter line elevations at any point along the street.
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Community Development Department STORM DRAINAGE
d. Hydraulic grade lines shall be shown on all profile drawings.
5. Manhole Locations
Manholes are required at the following locations:
a. Size or cross section changes.
b. Inlet lead and conduit intersections.
C. Changes in pipe grade.
d. Street intersections.
e. A maximum spacing of 500 feet measured along the conduit run.
f. Manholes shall be placed so as not to be located in driveway or sidewalk areas.
g. Adjust manhole frames and covers within the limits of the pavement to meet
the proposed final top of slab.
6. Inlets
a. Locate inlets at all low points in gutter.
b. Valley gutters across intersections are not permitted.
C. Inlet spacing is generally a function of gutter slope. For minimum gutter
slopes of 0.30 percent, the maximum spacing of inlets shall result from a
maximum gutter run of 350 feet from a high point in the pavement to an inlet
on a continuously graded street section, for a maximum spacing of 700 feet
between inlets.
d. If gutter slopes are less than 0.30 percent, the Director of Community
Development shall determine the inlet spacing. The acceptable minimum
gutter grade is 0.20 percent.
e. Use only Standard Inlets:
Inlet
Application
Capacity
Type A
Parking Lots/Small Areas
2.5 cfs
Type B-B
Residential
5.0 cfs
Type D
Parking Lots
2.0 cfs
Type E
Roadside ditches
20.0 cfs
Type H-2
Residential / Commercial
5.0 cfs
£ Do not use 'Beehive" style grate inlets or other "specialty" inlets.
g. Do not use grate top inlets in an unlined roadside ditch.
h. Place inlets at the end of curb return on side streets when such streets intersect
streets of a higher classification, unless special conditions warrant otherwise
and are approved by the Director of Community Development.
i. Storm sewer inlets shall be established in such numbers and in such locations as
to effectively drain storm water from paved sections. A graphical plan and
calculations of the hydraulic gradient shall be furnished by the design engineer.
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Community Development Department STORM DRAINAGE
C. Consideration of Overland Flow
Design Frequency. The design frequency for consideration of overland sheet
flow shall consider extreme storm events which exceed the capacity of the
underground storm sewer system, resulting in ponding and overland sheet flow
through the development to the primary drainage outlet.
2. Relationship of Structures to Street. All structures shall be constructed according to
the Flood Damage Prevention Ordinance and shall be higher than the highest level of
ponding resulting from the extreme storm event as shown on the latest City adopted
flood maps.
3. Calculation of Flow.
a. Streets will be designed so that consecutive high points in the street will
provide for a gravity flow of drainage to the ultimate outlet.
b. The maximum depth of ponding at high points will be the top of curb of streets
with curbs, or the elevation of the centerline of roads without curbs.
C. The maximum depth of ponding at low points will be 9 inches above the
gutter elevation of curb of streets with curbs or 3 inches above the elevation of
the centerline of streets without curbs.
d. Sheet flow between lots can be provided only through a defined drainage
easement.
e. A map shall be provided to delineate the flow direction of the extreme event
through a proposed development and how this flow is discharged to the
primary drainage outlet.
f. In areas where ponding occurs and no sheet flow path exists, a calculation shall
be provided to show that run-off from the 100-year event can be conveyed and
remain in compliance with the other terms of this Section.
4. Overland flow shall enter outfall drainage facilities (channels or detention ponds)
through a storm sewer with its last run sized to convey the 100-year event.
Calculations shall be submitted for sizing the structure and determining that adequate
inlet capacity exists.
Maintain pre-existing natural overland flow of storm water and provide protection for
adjacent properties from re -directed storm water flows.
6. Show contours of adjacent properties within 200 feet of development greater than 5
acres, and account for natural and existing overland flow or channelized flows.
D. Design of Open Channels
Design Frequency
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Community Development Department STORM DRAINAGE
a. Open channels shall be designed according to methods described in the
GCCDD & HCFCD Criteria Manuals.
b. Design standards for channel construction shall follow the requirements
specified in the GCCDD & HCFCD Criteria Manuals.
C. Design standards for the outfalls into channels shall conform to those in the
GCCDD & HCFCD Criteria Manuals.
2. Determination of Water Surface Elevations.
a. Water surface elevations shall be calculated using Manning's Equation and the
Continuity equation.
b. For the design storm event, the water surface for ditches and channels shall be
calculated to remain within the banks and at or below the required freeboard.
Design of Culverts
a. Head losses in culverts shall conform to TxDOT Bridge Division Hydraulics
Manual, Chapter 4 - Culverts.
E. Design of Roadside Ditches
1. Design Frequency
a. Roadside ditches are permissible only for single-family residential lots having
widths larger than, or equal to, 120 feet.
b. Design storm event for a roadside ditch shall provide 0.5 feet of freeboard
below the edge of pavement or the natural ground at the right-of-way line,
whichever is lower.
C. The design must include an extreme event analysis to indicate that adjoining
structures will not be flooded.
Velocity Considerations
a. For grass -lined sections, the design velocity shall be 2.0 feet per second during
the design storm event. The maximum velocity shall be 5 feet per second.
b. A grass lined or unimproved roadside ditch shall have side slopes no steeper
than 3 horizontal to 1 vertical.
C. Minimum grades for roadside ditches shall be 0.20%.
d. Calculation of velocity shall use a Manning's roughness coefficient of 0.040 for
earthen sections and 0.025 for ditches with paved inverts.
e. Use erosion control methods acceptable to the City when design velocities are
calculated to be greater than 3 feet per second and are approved by the City.
3. Culverts
a. Culverts shall be placed at all driveway and roadway crossings, and other
locations where appropriate.
b. Culverts shall be designed assuming inlet control.
Revised 9/2008 Section V Page 11 of 18
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Community Development Department STORM DRAINAGE
C. Roadside culverts shall be sized based on drainage area. Calculations shall
provide for each block based on drainage design criteria presented in this
manual.
d. Cross open channels with roadside culverts no smaller than 18 inches in
diameter or equivalent. The size of culvert used shall not create a head loss of
more than 0.20 feet greater than the normal water surface profile without the
culvert.
e. Use erosion control methods acceptable to the City when design velocities are
calculated to be greater than 3 feet per second and approved by the City.
f. Sloped end treatments (S.E.T.) are required on all TxDOT Highways.
Depth and Size Limitations for Open Ditches
a. Residential streets - the maximum depth shall not exceed 2.5 feet below the
edge of pavement.
b. Roadside ditch bottoms shall be at least 2 feet wide.
C. Ditches in adjoining and parallel easements shall have the top of bank not less
than 2 feet from the outside easement line or edge of pavement when
applicable.
d. Roadside ditch side slopes shall not exceed 3 horizontal to 1 vertical.
e. Design storm event for a roadside ditch shall provide 0.5 feet of freeboard
below the edge of pavement or the natural ground at the right-of-way line,
whichever is lower.
F. Design of Outfalls.
Outfall design shall conform to GCCDD and HCFCD standards as applicable.
2. Detention pond and storm sewer outfalls shall be placed one foot above the flowline
of the receiving channels, creeks and detention pond, or two foot above normal water
elevation, whichever is greater.
Flowlines of storm sewer outfalls shall be located 6 inches above the flowline of a
receiving roadside ditch.
G. Storm Water Detention
1. Application of Detention.
a. As a normal consideration, storm water detention shall be required. The use of
on -site detention is required under certain circumstances enumerated in
Subsection G, Items 6 and 7, in order to mitigate potential damage to existing
structures unless the current infrastructure is improved, or the City has
developed a plan for a detention facility to serve the overall area.
b. Design calculations for sizing the detention basin and related structures shall be
performed by the applicable method described in the following sections.
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Community Development Department STORM DRAINAGE
C. All calculations shall be sealed and signed by a Professional Engineer licensed
by the State of Texas.
d. A parking lot with a curb may be used as part of the detention system, provided
that the maximum depth of water over the inlet throat flow line does not exceed
9 inches and the maximum depth in any parking stall does not exceed 6 inches.
Calculation of Detention Volume
a. The Modified Rational Method shall be used to determine the detention storage
volume for developments that are 5 acres or smaller.
b. A simplified method may be used for determining the amount of detention
volume required based upon a rate of 0.45 acre-feet/acre, as found in the
GCCDD Criteria Manual. This method may be used for developments less
than 5 acres.
C. The Triangular Hydrograph method shall be used for determining the amount
of detention volume required for development of 100 acres or less.
d. The Unit Hydrograph Method, which calculates the required detention storage
volume by determining the difference in volumes between the inflow and
outflow hydrographs, may be used for developments less than 100 acres.
e. For developments with more than 100 acres, a detailed hydrologic analysis
utilizing the HEC-1 Flood Hydrograph method shall be required.
Calculation of Outlet Size
Outfalls which utilize a pipe restrictor to control outflow shall use the orifice
equation.
a. Reducer or Restrictor Pipes shall be sized as follows:
(1) Use the following equations to calculate the required outflow orifice:
Area of pipe = nd2A
Q = CA (2 gh)�"
D=Qia /2.25h-va
Where Q = outflow discharge in cfs.
C=0.8
h = water surface differential (ft)
D = orifice diameter (ft)
A = area of pipe (ft')
g = gravity (32.2 ft/s2)
(2) For head differential in systems outfalling into a roadside ditch or storm
sewer, the actual head loss or 1 foot whichever is greater, shall be used.
For all other discharge conditions use 2 feet or the difference between
100 year water surface elevation and the elevation of the 25-year storm
in the receiving channel, whichever is greater.
(3) For detention systems outfalling into a public storm sewer, the restrictor
shall be sized based upon the peak 5-year developed flow.
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(4) For detention systems outfalling into a public roadside ditch, the
restrictor shall be sized based upon the peak 5-year undeveloped flow.
(5) For detention systems outfalling into creeks, channels or storm sewers
sized to carry the 25-year or 100-year storm, the restrictor shall be
metered to release the 5-year, 25-year and 100-year undeveloped flows.
(6) Restrictor shall be either the required diameter or the equivalent cross -
sectional area. The orifice diameter "D" shall be a minimum of 6 inches.
(7) Detention ponds less than 1 acre in size shall have a minimum of 4
inches of freeboard. All ponds 1 acre or larger in size shall have at least
1 foot of freeboard. Freeboard shall be measured from the maximum
100-year water surface elevation and shall not be used in the calculation
of storage or mitigation.
Detention Pond Structural Requirements
a. Side slopes shall not exceed a slope of 4 horizontally to 1 vertically.
b. Maintenance berms will be required in accordance with the Galveston County
Consolidated Drainage District Design Criteria Manual.
C. Ponds with lengths over 50 feet shall have a concrete pilot channel.
d. Concrete pilot channels shall have a minimum width of 4 feet and a minimum
thickness of 4 inches with #3 rebar spaced at 12 inches on center each way.
The concrete channels shall be constructed of 5-sack cement concrete with a
compressive strength of 3000 psi at 28 days. Provide a 1-inch depression per
every 1 foot of transverse slope with redwood headers spaced every 40 feet.
e. Single -user ponds may use a GCCDD-approved alternative to concrete pilot
channels.
f. Appropriate covering (grass, slope paving, etc.) shall be established on side
slopes and pond bottom to prevent erosion during periods of maximum water
velocity
g. A concrete gravity spillway, set at the maximum ponding elevation, shall be
provided at the detention pond outfall structure.
h. Wet detention ponds and ponds with vertical walls shall provide access for
safety and maintenance purposes. Wet detention systems shall have a method
in place to minimize stagnation, such as an aeration system.
i. "Dry " detention ponds shall not be designed with less than two feet of depth.
Ownership and Easements
a. Private Facilities
(1) Pumped systems shall not be allowed. Only detention facilities which
rely on gravity to discharge storm runoff will be allowed by the City and
the GCCDD.
(2) Responsibility for maintenance of the detention facility must be indicated
on the plat.
(3) All private properties being served shall have drainage access to
the pond.
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Community Development Department STORM DRAINAGE
(4) A private maintenance agreement must be provided when multiple tracts
are being served.
b. Public Facilities
(1) Facilities will only be accepted for maintenance by the City when such is
in the public interest.
(2) The City will require a maintenance work area 20 feet wide surrounding
the extent of the detention area. Public rights -of -way or permanent
access easements may be included as a portion of this 20-foot width.
(3) A dedication of easements or reserves must be provided by the plat.
(4) Proper dedication of public access to the detention pond must be shown
on the plat or by separate instrument. This includes permanent access
easements with overlapping public utility easements.
Off -Site Detention in the Galveston County Consolidated Drainage District
In Galveston County, off -site detention, such as regional or sub -regional detention,
may be purchased from the Galveston County Consolidated Drainage District
provided:
a. The detention facility is in the same watershed or sub -watershed as the site
being developed.
b. Notwithstanding any other provision contained herein to the contrary, detention
for construction or site development relating to single-family residential
construction on lots or tracts containing 3.5 acres or less that do not involve the
subdivision of land, and for construction or site development relating to
multiple -family or commercial construction on lots or tracts containing 2.0
acres or less that do not involve the subdivision of land, shall be in accordance
with GCCDD Form DR-001, a copy of which is made a part of this manual.
Cost is based on amount of impervious cover.
C. The development is less than or equal to 8 acres for any single-family
residential development or less than or equal to 5 acres for any other type of
development. Cost is determined using an engineered drainage plan.
d. Excess detention capacity may not be used for mitigation of fill in the flood
plain.
e. Regional Detention. It is the desire of the City of Friendswood that regional
detention be utilized when available. If new development is within the service
area of a publicly -owned or operated regional storm water detention facility,
connection to such regional facility shall be as required by the drainage master
plan applicable to such facility.
f. Regional Detention Purchase Requirements:
Residential 0-3.5 acres Impervious Cover Method
Residential 3.5-8 acres Purchase based on Engineered Drainage Plan@
Current GCCDD price
Residential 8+ acres No Purchase of Detention Available -Drainage
Plan Required
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Community Development Department STORM DRAINAGE
Commercial 0-2 acres Impervious Cover Method
Commercial 2-5 acres Purchase based on Engineered Drainage Plan@
Current GCCDD price
Commercial 5+ acres No Purchase of Detention Available -Drainage
Plan Required
7. Redevelopment and Additions in the Galveston County Consolidated Drainage
District
a. All improved residential lots (less than 3.5 acres) within an existing
subdivision served by a detention facility that is within the platted boundaries
of said subdivision and that has been previously accepted and approved by the
City and the GCCDD, shall be exempt from the regulation to purchase
detention for additional impervious cover.
b. Residential lots (less than 3.5 acres) in an existing subdivision without an
approved detention facility, may purchase regional detention from the GCCDD
for additional impervious cover based on the current fees.
C. All commercial (2.0 acres or less) and multi -family developments (3.5 acres or
less) served by a detention facility that has been previously accepted and
approved by the City and the GCCDD, shall be exempt from the regulation to
purchase detention for additional impervious cover.
8. Conveyance
a. The developer shall provide conveyance to a detention facility without having a
detrimental effect on any adjacent properties.
b. If conveyance is directed through properties not directly owned by the
developer, an executed contract or recorded deed between the parties agreeing
to the said conveyance must be presented to the City and the appropriate
drainage district entity.
C. This procedure is approved by both the City and the corresponding drainage
district entity (GCCDD or HCFD) during preliminary plan review.
1.05 RESERVED
1.06 SUBMITTALS
A. Preliminary Submittals- Submit for Review and Comment
1. One line drawings are required as part of the platting process. One line drawings
shall include:
a. Approximate definition of lots and street patterns.
b. The approximate drainage areas for each system.
C. A definition of the proposed drainage system by single line.
d. The proposed pipe diameters.
e. Any proposed drainage easements.
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f. Floodplain and floodway boundaries, if any.
B. Final Design - Submit the following for approval:
1. Copies of any documents which show approval of exceptions to the City design
criteria.
2. Design calculations for storm line sizes and grades, and for detention facilities, if
any.
3. Design calculations for the hydraulic grade line of each line or ditch, and for
detention facilities, if any.
4. Contour map and drainage area map of the project.
5. Plan and profile sheets showing storm sewer or open -ditch design (public facilities
only).
6. Projects located within a flood plain boundary or within a flood plain management
area shall:
a. Show the flood plain boundary or flood plain area, as appropriate, on the one -
line drawing or drainage area map.
7. Soil boring logs.
8. All drainage plans shall have a current FEMA flood zone determination statement.
C. Signature State - Submit the Following for Approval.
1. Review prints.
2. Original drawings.
3. Storm water detention maintenance agreement letters.
1.07 QUALITY ASSURANCE
A. Prepare calculations and construction drawings under the supervision of a Professional
Engineer licensed by the State of Texas and trained in the disciplines required by the
drawings. The final construction drawings and all design calculations shall be sealed,
signed, and dated by the Professional Engineer licensed by the State of Texas responsible
for the development of the drawings.
PART 2 EXECUTION
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2.01 RESEARCH REQUIREMENTS — Reserved
2.02 DESIGN ANALYSIS
A. All projects shall be tied to National Geodetic Survey (NGS) Datum adjustment which
matches the Federal Emergency Management Agency (FEMA) rate maps or the most
current NGVD which matches the FEMA rate maps. In the event GPS surveying is used to
establish benchmarks, at least two references to benchmarks relating to the FEMA rate
maps must be identified. Equations may be used to translate other datum adjustments to
the required adjustment.
B. Plan sets shall include a drainage area map, which shall contain all storm sewer drainage
calculations.
C. All drainage systems for curb -and -gutter pavements shall be underground closed conduits;
individual residential lot drainage is exempt. Drainage systems for pavements without
curb -and -gutter shall be roadside open -ditch sections.
D. Soil boring with logs shall be made along the alignment of all storm sewers having a cross
section equal to or greater than 72 inches in diameter or equivalent cross section area.
Boring should be taken at intervals not to exceed 500 linear feet and to a depth not less than
3 feet below the flow line of the sewer. The required bedding will be determined from the
soil boring.
E. Plan sets shall include the 5-year Hydraulic Grade Line for storm sewers and roadside
ditches on the plan and profile sheets.
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Community Development Department
SECTION VI
SITE DEVELOPMENT
Design Criteria Manual
SITE DEVELOPMENT
1.0 GENERAL
Should any portion of this Section conflict with the Subdivision Ordinance (Appendix B) or the
Zoning Ordinance (Appendix C), the latter two (2) shall govern.
The Director of Community Development shall have the final interpretation of any provisions in
this manual.
The Director of Community Development has the right to issue administrative orders or design
criteria modifications for just cause related to any provisions or conditions in this manual.
Sanitary sewers located on private property that are not in a dedicated easement, are
under the jurisdiction of the Plumbing Code, and will be addressed/reviewed by the
Building Official.
1.01 CHAPTER INCLUDES:
Site Development
1.02 REFERENCES
A. City of Friendswood Zoning Ordinance.
B. City of Friendswood Subdivision Ordinance.
C. City of Friendswood Standard Details, latest version. These details can be purchased from
Community Development or downloaded from www.ci.friendswood.tx.us
D. Texas Department of Transportation -Traffic Control Plan
1.03 DEFINITIONS
A. Commission — Planning and Zoning Commission
1.04 DESIGN REQUIREMENTS
A. Site Development Requirements
1. General Requirements
a. Site development plans for all site developments within the City of
Friendswood shall be approved by the City prior to construction.
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b. Site developments, not including single family residential, shall include any
project that affects public water, wastewater, storm drainage, sidewalks or
paving facilities.
C. All site developments shall conform to the requirements of these Standards, the
2003 International Code Series, and all applicable rules and regulations of the
City of Friendswood.
d. All wastewater, drainage and paving site development improvements, up to and
including the connection to the public system, shall be privately owned,
operated and maintained. All water site development improvements, up to, but
not including, the meter and meter vault, shall be privately owned, operated
and maintained
e. Restore the City of Friendswood rights -of -way or easements to existing or
better condition than that prior to start of work.
f. Private utilities and service lines shall be placed in an easement on the property
being served.
Design Review Requirements for Site Development Plans.
a. All site development plans for proposed developments shall be submitted to the
Community Development Department for approval prior to construction. Site
development plans shall show all proposed water, wastewater, paving, parking,
drainage, street signage, streetlight locations, flood protection facilities, and
sidewalks with approved ADA ramps locations and a traffic control plan
b. A traffic impact study shall be required for any development proposal expected
to generate traffic volumes that will significantly impact the capacity and/or
safety of the street system. All proposed developments generating volumes of
5,000 trips per day or greater shall abide by this criteria. The trip estimate shall
be based on the latest version of the Institute of Transportation Engineers' Trip
Generation Manual.
c. The developer should first schedule a Development Review Committee meeting
with Community Development Department staff. At this meeting, infrastructure
issues and the feasibility of developing the site will be discussed.
d. Based on the DRC, the developer shall prepare a site plan for submittal to be
reviewed by staff. The developer shall consult with staff until all significant
issues surrounding the proposed site plan and development are resolved prior to
proceeding to the Commission for review and possible approval.
e. The final site plan is prepared after all comments on staff review have been
addressed. Any applicant may submit a site plan for consideration by the
Commission at any time after the staff review is completed. The Commission
reviews the final document for completeness and public awareness. The
submittal for the final site plan requires that nine (9) copies of:
1. Site Plan
2. Landscaping Plan
3. Elevation Plan
and three (3) copies o£
1. Drainage Plan
2. Utility Plan
3. Grading Plan
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4. Photometric Plan
5. Storm Water Pollution Prevention Plan
to be provided to Community Development Department staff at least three (3)
days prior to the next regularly scheduled Commission meeting.
f. Approval from the appropriate drainage entity is required prior to Commission
approval. Once the site plan is approved, the developer may begin the building
permitting process.
g. Three (3) copies of the site development plans shall be submitted to the Building
Official for review. The City will typically respond within two (2) to four (4)
weeks of the initial submittal.
h. When plan changes are requested, two (2) copies of the revised site development
plans shall be resubmitted to the City for final review, which will ultimately
result in the issuance of the building permit(s).
Building Slab Elevations - Minimum building slab elevations shall conform to the
requirements of the City of Friendswood Flood Damage Prevention Ordinance and
adopted flood zone maps.
4. Water Service - Water service lines and meters shall be sized in accordance with
requirements set out in the Waterline Distribution System Design Requirements.
Sanitary Sewer Service - Sanitary sewer service leads are normally installed during
construction of the public sanitary sewer. When a sanitary sewer service lead is to be
installed for a site development, refer to the Wastewater Collection System Design
Requirements. All lots, tracts, or reserves shall be connected directly to a public
sanitary sewer by a single lead, except as specifically approved by the City. The City
shall be contacted for all sanitary sewer connections for commercial projects within
the City.
Site Drainage Requirements - All commercial, industrial, office, recreational, and
multi -family tracts shall have an internal drainage system. The internal drainage
system shall collect all site runoff and direct it into a private storm sewer system that
shall connect to the public drainage facilities in the area. Any exceptions require
specific approval from the City.
a. The internal site storm sewer shall be connected to a public storm sewer at a
manhole or at an inlet adjoining the site. The site drainage outfall shall be
connected to the nearest existing drainage system with adequate capacity to
serve the drainage area. Where extension of the existing drainage system is
required, all costs for extension shall be the responsibility of the development.
b. All internal facilities shall be designed by a Professional Engineer licensed by
the State of Texas and shall be sized to drain the site in accordance with these
standards.
C. Drainage calculations shall be submitted with all site development plans.
Other supporting data may be required by the City.
d. When the site drains directly into a Galveston County or Harris County facility
and/or into a TxDOT or county right-of-way, the appropriate governmental
entity(s) shall approve the site development connection to the public facilities.
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7. Driveways
a. It is desirable to minimize the number of non-residential driveways on all
streets in order to reduce the number of conflict points and facilitate traffic
flow. It is recognized, however, that certain existing tracts may not be able to
fully comply with the following standards due to limited frontage or other
constraints.
b. When compliance with these criteria is precluded for any reasons, attempts
should be made to obtain alternative access where feasible, including joint
access driveways, access easements to adjoining properties or access to
intersecting streets.
C. If it can be demonstrated to the City Engineer that sufficient attempts to secure
alternative access have been made and that such access is still not possible, the
City Engineer may accept a Traffic Impact Analysis performed by a
Professional Engineer licensed by the State of Texas to permit a deviation to
the driveway spacing requirements indicated herein.
d. Residential driveways shall be a minimum of 12 feet wide and a maximum of
18 feet wide at the right-of-way line and should be placed at least 25 feet away
from the property line at the intersection of two (2) streets and at least five (5)
feet from a property line between two (2) properties.
e. Residential lots must have a minimum of 100 feet of frontage in order to be
eligible for a circular driveway on the lot, and the two (2) driveways shall have
at least 45 feet of separation between them.
f. Non-residential driveways shall be a minimum of 25 feet wide and a maximum
of 35 feet wide. Non-residential driveways shall be spaced with a minimum of
50-foot separation.
g. Non-residential driveways on major thoroughfares/boulevard streets shall be
placed no closer than 125 feet from the ultimate curb line of the intersecting
major thoroughfare or boulevard street. Non-residential driveways on
collector/ minor streets are to be placed no closer than 75 feet from the
ultimate curb line of the intersecting major thoroughfare/boulevard street.
Non-residential driveways on major thoroughfares/boulevard streets are to be
placed no closer than 75 feet from the ultimate curb line of the intersecting
collector commercial/minor street.
h. For purposes of determining the separation distance, the back of curb or edge
of street shall be used in conjunction with the edge of driveway which is
closest and parallel to the street from which the measurement is to be taken.
i. Non-residential tracts with less than 150 feet of frontage on a public street shall
have no more than one (1) driveway. Commercial tracts with between 150 and
320 feet of frontage on a public street shall have no more than two (2)
driveways. Commercial tracts with between 321 feet and 600 feet of frontage
on a public street shall have no more than three (3) driveways. Commercial
tracts with over 600 feet of frontage on a public street shall have the number of
driveways specially designated and specifically approved by the City.
j. Non-residential driveway connections to the public street shall be approved and
inspected by the City, TxDOT or county representatives or appropriate entity.
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k. Driveway radii shall not extend beyond the projection of a property line
perpendicular to the back of the curb.
1. Driveways shall be installed according to the City of Friendswood Standard
Details.
in. Driveways shall be evaluated with respect to location of existing or proposed
signage, landscaping and structures for adequate sight distance.
n. A note stating, "Access to adjacent property and common driveways may be
required," shall be placed on the site plan.
o. Curb returns for driveways shall be, at a minimum:
i. For residential driveways:
a. 5 feet on local streets less than 28 feet in width
b. 10 feet on collector streets, major thoroughfares and boulevards,
and local streets greater than 28 feet in width
ii. For non-residential driveways:
a. 25 feet on local streets less that 28 feet in width
b. 35 feet on collector streets, major thoroughfares, boulevards, and
local streets greater than 28 feet in width
8. Fire Lanes
a. Fire lane easements shall be required on all multi -family and non-residential
tracts if any part of a building is greater than 150 feet from either a fire lane or
a public street right-of-way.
b. Fire lanes shall be either 20 feet wide with a 25-foot radius or 25-feet wide
with 20 feet radius.
C. Fire lanes shall be constructed using the same pavement structural
requirements as a public pavement. Alternate materials may be used with
specific approval from the City.
d. Fire lanes shall be designed to drain in compliance with the Site Development
Requirement.
e. Fire lane markings shall be provided as specified in the Friendswood Code of
Ordinances.
f. An emergency vehicle turn -around, whether a cul-de-sac of a radius required
by the Fire marshal or a T-head at least 120 feet in length, shall be required
under certain conditions.
9. Controlled Access Gate Requirements
a. Plans for access control systems shall be submitted to the Fire Marshal's
Office and approved prior to construction.
b. All access control gates shall have emergency means of operation in the
event of power loss.
C. Access control gates shall provide a clear, passable width of at least 20 feet.
d. A Knox® key switch shall be provided for all controlled access gates. The key
switch shall operate all gates.
e. A Knox® pad lock shall be provided for all non -motorized gates.
f. The location of the key switch shall be approved by the Fire Marshal's Office.
g. The owner or owners association shall maintain all parts of the access
system and keep them in good working order.
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h. The Fire Marshal's Office and Police Dispatch shall be notified
immediately of any damage to the access system that hinders access
including, but not limited to, damage to the key box, lock, or gates.
10. Pollution Prevention
A pollution prevention plan shall be provided for all site development projects.
a. Filter fabric fence shall be installed at the perimeter of the site before
construction begins.
b. Once construction is completed, either filter fabric fence, 5 feet of hydro -mulch
or sod shall be installed at the back of all curbs, or other Best Management
Practices shall be implemented.
C. Refer to the Storm Water Ordinance for additional requirements.
11. Parking Lot Guidelines
A parking lot layout is required to ensure that adequate off-street parking is provided
with the construction, alteration, remodeling or change of use of any building or
change in use of land.
a. Off-street parking spaces shall be located on the same lot, tract, parcel, or
premises as the use being served or on other property of the same or less
restrictive zoning classification that the owner of the premises being served has a
continuing right to use for parking. When the off-street parking spaces are not
located on the same lot, tract, parcel, or premises being served, the distance from
the center of the parking lot to an entrance to the building or use shall not exceed
500 feet in distance, measured along the shortest available pedestrian route with
public access.
b. Any existing building or use that is enlarged, structurally altered, or remodeled to
the extent of increasing or changing the use by more that 50 percent as it existed
shall be accompanied by off-street parking for the entire building or use. When
the enlargement, structural alteration, or remodeling is to the extent that the use is
not increased or changed by more than 50 percent, additional off-street parking
shall only be required for the increased or changed floor area or use.
c. Existing parking spaces may not be used to satisfy additional off-street parking
requirements unless the existing spaces exceed the number recommended for the
building or use for which the existing spaces are associated.
d. The number of off-street parking spaces recommended for each building or use
shall be determined by reference to the Parking Group Table in Appendix C-
Zoning of the Code of Ordinances. Where several different property uses will
share a joint parking area, the parking should be computed based upon the overall
development. Shopping centers containing not more than 200,000 square feet of
gross leasable floor area should have a minimum of six spaces per 1,000 square
feet of gross leasable floor area. Shopping centers containing more than 200,000
square feet of gross floor area should have a minimum of 5.5 spaces per 1,000
square feet of gross leasable floor area.
e. The design and dimensions of off-street parking areas shall be in accordance with
the following table of minimum dimensions. Minimum stall width shall be nine
feet, except for residential and all -day office parking which may utilize stalls 8'/2
feet in width, provided that minimum aisle widths are increased by one foot. In
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addition, the dimensions of up to 20 percent of the total number of off-street
parking spaces may be reduced to eight feet in width and 16 feet in depth to
accommodate compact automobiles, and such spaces must be so marked. All
dimensions below are in feet:
Angle
(degrees)
00 350 450 600 900
Stall, parallel to aisle
23.0
18.0
12.7
10.4
9.0
Stall, perpendicular to aisle
9.0
16.5
19.0
20.0
18.0
Aisle width, one-way
12.0
12.0
12.0
16.0
24.0
Aisle width, two-way
22.0
22.0
22.0
24.0
24.0
Cross aisle, one-way
11.0
11.0
11.0
11.0
11.0
Cross aisle, two-way
22.0
22.0
22.0
22.0
22.0
Refer to Appendix B-Figure 8 of this Design Criteria Manual for Off-street
Parking Diagram
f. Off-street parking spaces shall be clearly marked. Parking spaces abutting an
adjoining property line or street right-of-way shall be provided with wheel guards
or bumper guards located such that no part of a normally parked vehicle will
extend beyond the property line. When wheel guards are used, they shall be
centered 2.5 feet from the property line for 90-degree parking, 2.3 feet for 60-
degree parking, and 2.0 feet for 45-degree and 30-degree parking.
g. Approval of the parking layout and design of all off-street parking areas shall be
given by the Director of Community Development. The Director of Community
Development shall determine that spaces provided are usable, and that the
circulation pattern within the area is adequate.
h. One ADA-compatible space is required for every 25 regular spaces (full-sized or
compact -sized) or for any increment thereof.
2.0 EXECUTION
2.01 RESEARCH REQUIREMENTS
A. Discuss project concepts outlining proposed features and usage with the City.
B. Research existing utility and right-of-way information.
C. Verify that no restrictions exist that could result in denial of the project concept.
2.02 DESIGN ANALYSIS - Reserved
2.03 DRAWINGS
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A. The site development plan shall include layout sheet(s) providing a photometric layout of
the site complete with location of proposed lights, information on light heights and type of
light standard proposed.
B. The site development plan shall include an overall drainage layout showing:
Total area (in acres) of site to be drained.
2. Area (in acres) drained to each inlet.
3. Contours or an adequate number of spot elevations to indicate area drained to each
inlet.
4. Top elevation and flowline elevation at each inlet.
5. Gradient and size on each private storm sewer.
6. Computations to support pipe sizes and grades shown (minimum private storm size
shall be 10 inches.)
7. Design velocity for storm sewers shall be 3 feet per second.
8. A TxDOT or a county permit shall be required for drainage affecting a state or
county owned/maintained facility. Submit permit with site plan.
9. The drawings shall be prepared and sealed by a Professional Engineer licensed by the
State of Texas.
10. The size and location of any required detention facility shall be indicated on the
plans, along with the size and location of the outfall structure.
C. All site development plans shall be approved by the appropriate drainage entity prior to
City approval being granted.
E. The site plan shall show all water and sewer service lines with sizes, grades and alignments,
and showing appropriate ties into existing public lines.
E. The site development plan shall show all parking areas.
F. The site development plan shall indicate the types and location of all existing and proposed
landscaping. Landscaping shall meet the minimum requirements of Appendix C-Zoning
Ordinance. A tree survey is required for first 20 feet of depth adjacent to all proposed
streets. If no trees exist, a note to that effect shall be placed on the site development plan.
The qualified tree list can be found in Appendix C of this Design Criteria manual.
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SITE DEVELOPMENT
G. The site development plan shall show the location, height and area of all proposed
buildings. All setback lines as required by the Zoning Ordinance shall also be shown, with
a dimension called out on the site plan between the building and the site boundary.
H. The land use for all adjacent property shall be shown on the site development plan.
I. All parking lot pavement for site development plans shall be engineered to provide for
operation and by vehicles normally expected to utilize the parking area, and the thickness
of paving shall be based upon the soil conditions underlying the parking area. A
Professional Engineer licensed in the State of Texas shall certify the design submitted for
approval.
J. Concrete sidewalks (a minimum of 4 feet wide and 4 inches thick with steel reinforcement)
shall be required along all street frontages. The design and installation of such sidewalks
shall comply with Texas Accessibility Standards Architectural Barriers requirements and
the City of Friendswood Standard Details. The location of all proposed and existing
sidewalks shall be shown on the site development plan.
K. Show location of signs, screening walls or fences (indicate height, maximum 8 feet) and
dumpsters (with appropriate screening).
L. If the site is located within the Community Overlay Development District, a plan note shall
be made on the site development plan indicating such; and that the site development will
conform the Zoning Ordinance requirements.
M. No improvements in or to public right-of-way shall be made without prior City approval.
This includes planting trees in a public right-of-way of residential and non-residential areas
or in any utility or drainage easement. Only Class 2 and Class 3 trees listed in Appendix C
of this Design Criteria Manual may be planted in a public right -of way if such planting is
approved by the City. No trees of any class may be planted in utility or drainage
easements.
Revised 9/2008 Section VI Page 9 of 9
City of Friendswood Design Criteria Manual
Community Development and Public Works Department MODIFICATION PROCEDURES
SECTION VII
MODIFICATION PROCEDURES
The City of Friendswood's Director of Community Development may grant a modification to the Design
Criteria Manual, if the applicant can prove that the listed circumstances apply. A written application by
the applicant must be filed with the Director of Community Development along with sealed engineering
reports, drawings, etc. The following is a list of circumstances to apply for a modification:
I . There is no available alternative or option that would allow compliance with the
Design Criteria Manual in lieu of a modification; and
2. There are special circumstances or conditions affecting the applicant's land
involved such that the strict application of the provisions of this chapter would deprive the
applicant of all reasonable use of his land; and
3. The granting of the modification will not be detrimental to the public health, safety, or
welfare; or injurious to other property in the area; and
4. The granting of the modification will not increase the 100-year flood plain base flood
elevation on the upstream or downstream side of the applicant's property; and
5. The granting of the modification will not have the affect of preventing the orderly
development of other land in the area in accordance with the provisions of the Design Criteria
Manual.
The Director of Community Development may grant a modification to the Design Criteria Manual if it is
determined, based upon the evidence presented, that an undue hardship or deprivation of reasonable use
of land may result from strict compliance with the Design Criteria Manual. A monetary hardship to the
applicant, standing alone, shall not be deemed to constitute undue hardship.
A modification may be granted so that substantial justice is done and the public interest secured, provided
that such modification shall not have the effect of nullifying the intent and purpose of the Design Criteria
Manual.
A Design Criteria Modification Form is included as Attachment 3.
Revised 9/2008 Section VII Page I of I
CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
Design Criteria Manual
Appendix A
Attachments
ATTACHMENTS
Lift Station Start-up Log
2. ANSI/NSF Standard 60 and 61 Certification
3. Design Criteria Modification Form
4. GCCDD Form DR-001
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Attachment 2
TEXAS NATURAL RESOURCE CONSERVATION COMMISSION
PDW PROGRAM STAFF GUIDANCE
GuidanceTitle: ANSI/NSF STANDARD 60 AND 61 CERTIFICATION
Rules Affected: 30, TAC, §290.42(I), §290.43(c)(8), §290.44(a)(1) and §290.44(I)(2)(B)
PAGE 1/1
Sections §290.42(I), §290.43(c)(8), §290.44(a)(1) and §290.44(I)(2)(B)in our current Rules and Regulations for
Public Water Systems concern ANSI/NSF product certification for all direct and indirect additives used in the
production, treatment, storage and distribution of public drinking water. All such products must conform to
ANSI/NSF Standard 60 for direct additives and ANSI/NSF Standard 61 for indirect additives as of January 1,
1993. Since these requirements went into effect wee have been contacted by a number of water system officials
and consulting engineers concerning the limited availability of materials which meet these standards. In addition,
manufacturers and distributors have informed us of lengthy delays in the certification process. We feel that these
concerns are valid and that an interim guidance is necessary until more materials have made their way through
the certification process.
• The following guidance has been established:
All materials which come in direct or indirect contact with public drinking water in any stage
of treatment must conform to ANSI/NSF Standard 60 for direct additives and ANSI/NSF
Standard 61 for indirect additives. Should no certified material for the intended purpose exist
or if there are no such certified materials currently marketed in the State of Texas, a material
may be conditionally accepted for use if:
The material was previously approved by a nationally recognized authority such as EPA,
NSF, USDA or USFDA for direct, indirect or incidental contact with water and/or food,
and
Proof of submission of the material to an organization accredited by ANSI for
certification under ANSI/NSF Standards 60 and 61 is provided. Such proof shall consist
of either a dated receipt from NSF, UL or other ANSI accredited organization or a letter
from the accredited organization acknowledging that the material has been submitted
for evaluation and certification.
The conditional acceptance of any single product shall expire when the conditionally accepted product or an
alternate competing product receives certification and is marketed within the State of Texas, or the conditiona
accepted product is denied certification by an ANSI accredited organization.
January 1, 1996
Effective Date
N/A
Expiration Date
END
�leeen f: �Ymlc%ry
Steven E. Walden, R.S., Manager
Public Drinking Water Section
Water Utilities Division
Attachment 3
CITY OF FRIENDSWOOD
DESIGN CRITERIA MODIFICATION FORM
Section VII.
Modifications to standards identified in the Design Criteria Manual may be permitted by the City of Friendswood's
Director of Community Development. The modification proposal must be submitted by a Professional Engineer
licensed by the State of Texas and shall follow generally accepted engineering standards for traffic, sidewalk and
other infrastructure as applicable, and such proposal contains the following information and substantiates the
findings in Paragraph 4 below. If an appeal to the City of Friendswood City Engineer decision is requested, The
Construction Board of Adjustment (hereinafter referred to as "the City") will review that appeal.
PROJECT NAME:
This entire form must be completed in its entirety. If form is submitted
incomplete, it will be administratively rejected.
PROJECT ENGINEER:
SUBMITTAL DATE:
SUBDIVISION NAME:
MODIFICATION
LOCATION:
1. Set forth the proposed deviation to the technical standard.
SPECIFIC PROPOSED DEVIATION FROM TECHNICAL STANDARD:
2. Set forth the impact such deviation has on speed differential and street capacity, the likelihood of accidents, the
long term maintenance and operation effect, the degree of functionality and efficiency, the technological
advancements involved, and other relevant matters.
IMPACT OF DEVIATION:
3. Show a comparison of the technical standard to the proposed deviation with respect to overall safety and quality,
speed differential, street capacity, existing and projected accidents, long-term maintenance and operation, degree
of functionality, degree of efficiency, technological advancements, and other relevant matters.
COMPARISON OF TECHNICAL STANDARD TO PROPOSED DEVIATION:
Describe all mitigating improvements that reduce the negative impact of the proposed deviation on overall safety
and quality, speed differential, street capacity, accident occurrences, long-term maintenance and operation,
degree of functionality, degree of efficiency and demonstrating the degree to which the proposed deviation
detrimentally affects the foregoing. Other relevant factors, including technological advances, should be
explained by describing how they will affect the proposed development. Mitigating improvements can include
but are not limited to, traffic control devices, pavement improvements, added acceleration or deceleration lanes
or reservoirs, and other on -site improvements.
MITIGATING IMPROVEMENTS THAT REDUCE NEGATIVE IMPACT:
SUMMARY & CONCLUSION/RECOMMENDATION FOR MODIFICATION:
List of Supporting Documentation Attached? Yes No
Seal of Professional Engineer:
Community Development Use ONLY
Reviewed By:
Date
Modification Request Approved / Denied By:
Copies of Backup Information/Notes Attached
Director of Date
Community Development
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CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
Design Criteria Manual
Appendix B
Figures
Figure
1.
Geometric Street Design Standards
2.
Divided Roadway Cross Sections — Urban
3.
Roadway Tapers For Subdivision Streets
4.
Undivided Roadway Cross Sections — Urban
5.
Typical Length of Median and Median Opening
6.
Median Nose and Left Turn Bay Design
7.
Offstreet Parking
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18
MIN
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a` I 22' �
Wheel
Gu ord {� 24'}}
NOTE: 2 5' 18'
Minimum stall widths shall be nine I M N. feel, except for residential and
oll-day office parking which may
ulilize stolls M feet in width, provided
that the minimum aisle widths are
increased by one foot. In addition,
the dimensions of up to 20 percent
of the total number of offset parking
spaces may be reduced to eight feet a
in widths and 16 feet in depth to
accommodate compact automobiles.
Parking spaces abutting an adjoining I WANGLE
property line or street right of way
shot[ be provided with wheel guards
or bumper guards so located that no
part of a normally parked vehicle will 16' 24'
extend beyond properly line. 0 Q 0 O Q
Wheel
Guard
2.3'
60" ANGLE
I
165
24'
l
lQ
.< <I 19
300 ANGLE ly y I 45°ANGLE
m 'I
a l0
a o_
OFFSTREET PARKING
STALL PERPENDICULAR TO AISLE
)COMMUNITY DEVELOPMENT DRAWN: os/oa N.T.S.
DETAIL offstreetparking
10.4
MIN.
CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
Design Criteria Manual
Appendix C
Parking Group Table
Parking Use Category Recommended Parking Spaces
Accommodation
Accommodation & Food Services
Adult establishment
Agricultural, Forestry, Fishing And
Hunting Uses
Arts, Entertainment & Recreations
Broadcast & Telecommunications;
Telecommunication Resellers: Information
& Data Processing Services
Car wash
Civic, Social and Fraternal Associations
Educational Services
(based on maximum design capacity)
Daycare center or pre -elementary
Elementary school
Jr. High School
High School or Vocational School
College or University
Finance & Insurance
Gas Station
Health Care & Social Assistance
Hospitals, Nursing & Residential Care
facilities
Information Services
Mining, Utilities, Construction,
Manufacturing, Transportation &
Warehousing
Mobile home
Non -store retailers
1 '/2 spaces for each room/dwelling unit
1 space for every 4 seats or 1 space for every 50 sq. ft. of
customer service area, whichever is greater
1 space for every 4 seats or 1 space for every 50 sq. ft. of
customer service area, whichever is greater
2 per site + 1 per 1,000 sq. ft. enclosed floor area
1 space for each 250 sq. ft. gross floor area
1 space for each 300 sq. ft. of gross floor area
2 per wash bay, 3 stacking spaces per bay
1 space for each 300 sq. ft. of gross floor area
1 space per 300 sq. ft. of gross floor area
1 space per 20 students and 1 space per staff faculty member
1 space per 15 students and 1 space per staff faculty member
1 space per 3 students and 1 space per staff faculty member
1 space per commuter student and 1 space per staff faculty
member
1 space for each 300 sq. ft. of gross floor area
1 space for each bay, plus 1 space for each pump island,
minimum 6 spaces
1 space for each 250 sq. ft. gross floor area
1 space for each 1 '/z beds
3 spaces for each 5 employees on largest shift, or 1 space per
600 sq. ft. of gross floor area
3 spaces for each 5 employees on largest shift, or 1 space per
600 sq. ft. of gross floor area
2 '/2 spaces per trailer unit
1 space for each 2,000 sq. ft. of gross floor area
Amusement and Recreation Industries
Arcade
1 space per 200 sq. ft. of gross floor area
Driving/archery/shooting range
1 space per 200 sq. ft. of gross floor area of indoor facilities,
plus 1 space per tee or target
Fairground, exhibition, carnival
1 space per 500 sq. ft. of outdoor site area, plus 1 space per
4 fixed spectator seats
Go-carts and all -terrain vehicles
1 space per 2 vehicles, plus 1 space per 4 spectator seats
Golf Course
I space per 150 sq. ft. of gross floor area of indoor facilities,
plus 5 spaces per green
Miniature Golf
1 space per 200 sq. ft. of gross floor area of indoor facilities,
plus 1.5 spaces per hole
Rodeo, circus, auto/motorcycle
1 space per 3 spectator seats
racing
Skateboarding, water slide
1 space per 200 sq. ft. of gross floor area of indoor facilities,
plus 1 space per 2 persons design capacity of outdoor
facilities
Sport fields, swimming pools,
1 space per 100 sq. ft. of gross floor area of indoor facilities
private parks and playgrounds
plus 1 space per 4 persons design capacity of outdoor
facilities, including both participants and spectators as
applicable
Tennis and other sport courts
2 spaces per court
Other Services
1 space for each 250 sq. ft. gross floor area
Professional, Scientific & Technical
I space for each 300 sq. ft. of gross floor area
Services: Management of Companies &
Enterprises; Administration/Support
Services
Public Administration 1 space for each 300 sq. ft. of gross floor area
Real Estate, Rental & Leasing 1 space for each 300 sq. ft. of gross floor area
Religious Organizations 1 space for each 4 seats in the largest auditorium, or 1 space for
each 800 square feet of gross floor area, which ever is larger
Residential Uses 2 spaces per household
Retail Trade 4 spaces for each 1,000 sq. ft. gross floor area
Transit & Ground Passenger 1 space per 100 sq. ft. of gross floor area
Transportation; Scenic & Sightseeing
Transportation
Truck Transportation; Warehousing & 1 space for each 1,000 sq. ft. non -office floor area plus 1 space
Storage for each 300 sq. ft. office area
Vehicle Dealers 1 space for each 5,000 sq. ft. of lot area
Whole Sale Trade 1 space per 2,000 sq. ft. of gross floor storage/sales area
CITY OF FRIENDSWOOD
COMMUNITY DEVELOPMENT DEPARTMENT
Design Criteria Manual
Appendix C
Qualified Tree List
Qualified Tree list by class of tree
Common name
Botanical name
Class
N/1
Site
Light
Size
E/D
Bald Cypress
Taxodium distichum
I
N
2,3
2
1
D
Bur Oak
Quercus macrocarpa
I
N
2
1
l
D
Cedar Elm
Ulmus crassifolia
1
N
2
1
2
D
Drummond Red Maple
Acer rubrum var. drummondii
1
N
2
1
2
D
Eastern Redbud
Cercis canadensis
I
N
2
2
2
D
Live Oak
Quercus virginiana
1
N
2
l
1
SE
Overcup Oak
Quercus lyrata
1
N
2,3
1
1
D
Pecan
Carya illinoensis
1
N
2
1
1
D
Possumhaw Holly
Ilex decidua
1
N
2
1,2
3
D
Shumard Red Oak
Quercus shumardii
1
N
2
1
1
D
Southern Magnolia
Magnolia grandiflora
l
N
2
1
1
E
Swamp Chestnut Oak
Quercus michhauxii
I
N
2,3
1
1
D
Sweet -Bay Magnolia
Magnolia virginiana
1
N
2
2
2
E
Wax Myrtle
Myrica cerifera
1
N
2/3
1
3
E
American Elm
Ulmus americana
2
N
2
l
1
D
American Sycamore
Platanus occidentalis
2
N
2
1
1
D
Anacua/Sandpaper Tree
Ehretia anacua
2
N
2
1
2
E
Arrow -wood Viburnum
Viburnum dentatum
2
N
2
2
3
D
Black Hickory
Carya texana
2
N
2
1,2
2
D
Black Walnut
Juglans nigra
2
N
2
1,2
1
D
Blackgum
Nyssa sylvatica
2
N
2,3
1,2
3
D
Callery Pear/Braford
Pyrus calleryana
2
I
2
l
3
D
Carolina buckthorn
Rhamnus caroliniana
2
N
2
1,2
3
D
Chalk Maple
Acer leucoderme
2
N
2
2
2
D
Cherry Laurel
Prunus caroliniana
2
N
2
2
2
E
Chinese Elm
Ulmus parvifolia
2
I
2
l
2
D
Chinquapin Oak
Quercus muhlenbergii
2
N
2
1
1
D
Common Crapemyrtle
Common Fig
Common Persimmon
Eastern Red Cedar
Eve's Necklace
Green Ash
Huisache
Loblolly Pine
Mexican Plum
Nuttail Oak
Ornamental Holly
Paloverde
Parsley Hawthorn
Post Oak
Red Bay
River Birch
Rough -leaf Dogwood
Rusty Blackhaw Viburnum
Sassafras
Scarlet (Red) Buckeye
Shagbark Hickory
Slash Pine
Snowbell
Southern Red Oak
Sweetgum
Texas Mountain -Laurel
Texas Persimmon
Texas Pistache
Texas Redbud
Water Hickory
Water Oak
Western Soapberry
White Ash
White Oak
Willow Oak
Winged Elm
Woollybucket Bumelia
Wright Acacia
Yaupon Holly
American Elderberry
American Holly
American Hornbean
Black Locust
Lagerstroemia indica
2
I
2
1
3
D
Ficus carica
2
I
2
1
3
D
Diospyros virginiana
2
N
2
1
2
D
Juniperus virginiana
2
N
2
1,2
2
E
Sophora affinnis
2
N
1
1
3
D
Fraxinus pennsylvanica
2
N
2,3
1,2
1
D
Acacia famesiana
2
N
1
1
3
D
Pinus taeda
2
N
2
1
1
E
Prunus mexicana
2
N
1
1
3
D
Quercus nuttallii
2
N
2/3
1
1
D
Ilex spp.
2
I
2
1,2
3
E
Parkinsonnia aculeata
2
N
1
1
2
D
Crataegus marshallii
2
N
2
2
3
D
Quercus stellata
2
N
2
2
1
D
Persea borbonia
2
N
2
2
2
E
Betula nigra
2
N
2,3
2
2
D
Corpus drummondii
2
N
1,2
3
3
D
Viburnum rufidulum
2
N
2
2
3
D
Sassafras albidum
2
N
2
2
2
D
Aesculus pavia
2
N
2
2
3
D
Carya ovata
2
N
2
1
1
D
Pinus elloittii
2
1
2
1
1
E
Styrax americana
2
N
2
1,2
3
D
Qurcus falcata var. pagoda
2
N
2
1
1
D
Liquidambar styraciflua
2
N
2
1
1
D
Sophora secundiflora
2
N
1
1
3
E
Diospyros virginiana(male)
2
N
1
1
3
D
Pistacia texana
2
N
1
1
3
D
Cercis canadensis texensis
2
N
1,2
2
3
D
Carya aquatica
2
N
2,3
1
2
D
Quercus nigra
2
N
2/3
1
1
D
Sapindus drummondii
2
N
2
1
2
D
Fraxinus americana
2
N
2
1
1
D
Quercus alba
2
N
2
1
1
D
Quercus phellos
2
N
2/3
1
1
D
Ulmus alata
2
N
2
1
2
D
Bumelia lanuginosa
2
N
2
2
2
D
Acacua wrightii
2
N
1
1
3
D
Ilex vomitoria
2
N
2
1 /2
3
E
Sambucus canadensis
3
N
2
2
3
D
Ilex opaca
3
N
2
2
2
E
Carpinus caroliniana
3
N
2
2
2
D
Robinia pseudoacacia
3
N
2,3
1
2
D
Black Willow
Box -Elder Maple
Camphor -Tree
Catalpa
Common Pear
Eastern Cottonwood
Flowering Crabapple
Hercules -Club Prickly -Ash
Honey -Locust
Japanese Yew
Japanese Maple
Loquat
Mesquite
Mexican Buckeye
Red Mulberry
Sugar Hackberry
Vitex
Water Tupelo
Weeping Willow
Arborvitae
Arizona Ash
Berlandier Ash
Chinaberry
Chinese Pistache
Chinese Tallow
Eucalyptus
Golden-Raintree
Japanese Black Pine
Mimosa(Silktree)
Mulberry
Siberian Elm
Silver Maple
Tulip -Tree
Salix nigra
3
N
3
1
2 D
Acer negundo
3
N
2
2
2 D
Cinnamomum camphora
3
I
2
1
2 E
Catalpa bignonioides
3
N
2
1
2 D
Pyrus communis
3
N
2
1
2 D
Populus deltoides (male)
3
N
2
1
1 D
Malus spp.
3
1
2
1
3 D
Zanthoxylum clava-herculis
3
N
1
1
3 D
Gleditsia triacanthos
3
N
2,3
1
2 D
Podocarpus macrophyllus
3
1
2
1
2 E
Acer palmatum
3
1
2
2
3 D
Eriobotryajaponica
3
1
2
2
3 E
Prosopis glandulosa
3
N
1
1
2 D
Ungnadiaspeciosa
3
N
1
1
3 D
Morus rubra
3
N
2
1
2 D
Celtis laevigata
3
N
2
1,2
2 D
Vitex agnus-castus
3
I
1
1
3 D
Nyssa aquatica
3
N
3
2
1 D
Salix babylonica
3
1
3
1
2 D
Thuja spp.
4
1
Fraxinus velutina
4
1
Fraxinus berlandieriana
4
1
Melia azedarach
4
1
Pistacia chinensis
4
1
2
1
2 D
Sapium sebiferum
4
1
Eucalyptus spp.
4
1
1,2
1
3 E
Koelreuteria paniculata
4
1
2
1
2 D
Pinus thunbergi
4
1
2
1
2 E
Albizia julibrissin
4
1
Morus alba
4
I
2
1
2 D
Ulmus pumila
4
I
Acer saccharinum
4
1
Liriodendron tulipifera
4
I
2
1
1 D
Trees are divided into four classes. Class 1 and 2 trees are considered the most valuable in enhancing the environment and
are the most likely to prosper in the Friendswood area. Therefore, only Class 1 and 2 trees shall be approved as new
plantings for a) city parks and property, and parking lots and b) for streets or other public right-of-ways, respectively,
unless otherwise approved by the Director of Community Development on the advice of an Urban Forester. Species that
are classified as shade trees will reach a height and size that will conflict with overhead powerlines, permanent structures,
or the canopy will exceed the limits of a confined space. Species that are classified as small trees will not provide the
protection or aesthetic impact of a large shade tree, yet they are suitable for planting beneath powerlines and are good
alternatives for areas of limited space.
Class 1: for the most part this class is for trees that are native, will do relatively well in the Friendswood area, have few
diseases or pest problems, are easy to find in local nurseries and with few exceptions (redbud, possomhaw and waxmyrtle)
are larger in size.
Class 2: this class is for trees that are mostly native, will still do well in the Friendswood area, have little disease or pest
problems, sometimes not quite as easy to find in nurseries, are more varied in size and in many cases are more suitable for
wildlife. These trees tend to have either larger and messier fruit and/or are thornier than trees in Class 1. Some of these
trees are also more prone to some decay at maturity and might not do as well in urbanized areas.
Class 3: this class starts to pick up more introduced species, the trees might or might not do as well in the Friendswood
area, require a little more maintenance and care, the natives might be harder to find in a nursery while the introduced
species may be more readily available and in some cases these trees are more prone to decay, disease and pest problems.
Class 4: this class is exclusively introduced species. They may or may not do well in Friendswood. If they do grow well
they have the potential to become invasive species and cause problems for local ecosystems and are more prone to decay,
disease and pest problems. NOT RECOMMENDED FOR PLANTINGS.
Classifications
N--Native
I —Introduced
Site
1--Xerophytic (requires little water)
2--Mesic (requires moderate water with good drainage)
3--Aquatic (tolerates poor drainage once established 3 years)
Once Established
Size
1--60 feet and greater ultimate height (large shade tree)
2--30 to 60 feet in ultimate height (medium tree)
3--30 feet and less in ultimate height (small tree)
Foliage.
D--Deciduous (sheds leaves annually) If placed on the south and west walls will reduce indoor temperatures in summer
by shading the roof and walls. In winter, these trees allow sunlight through to help heat the house.
E--Evergreen (having green leaves/needles through out the year) Can create a wind break if placed on the Northwest
side of a building.
SE --Semi evergreen
For example, the code for Live Oak is 1/N/2/l/l, which indicates that the Live Oak is a Class 1 species that is native to
Texas, requires moderate water with good drainage, demands or tolerates full sun, and will exceed 60 feet in ultimate
height. As a shade tree, the Live Oak will provide protection and has aesthetic impact but the tree is not suitable for
planting beneath powerlines or within confined spaces, or in streets or other public rights -of -way.