O-2014-1296 - 4/10/2014ORDINANCE NO. 0-2014-1296
AN ORDINANCE AMENDING THE "CITY OF ROUND ROCK DESIGN
AND CONSTRUCTION STANDARDS - UTILITIES CRITERIA MANUAL"
ADOPTED BY ORDINANCE NO. G -04-12-16-13A1 BY AMENDING
SECTION 1 "WATER, REUSE WATER, AND WASTEWATER"; AND
PROVIDING FOR A SAVINGS CLAUSE AND REPEALING
CONFLICTING ORDINANCES AND RESOLUTIONS.
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF ROUND ROCK,
TEXAS:
The "City of Round Rock Design and Construction Standards - Utilities Criteria
Manual," Section 1 entitled "Water, Reuse Water, and Wastewater" is hereby amended
and same is attached hereto as Exhibit "A," and made a part hereof as if fully set out in
this ordinance.
II.
A. All ordinances, parts of ordinances, or resolutions in conflict herewith are
expressly repealed.
B. The invalidity of any section or provision of this ordinance shall not
invalidate other sections or provisions thereof.
C. The City Council hereby finds and declares that written notice of the date,
hour, place and subject of the meeting at which this Ordinance was adopted was posted
and that such meeting was open to the public as required by law at all times during
which this Ordinance and the subject matter hereof were discussed, considered and
formally acted upon, all as required by the Open Meetings Act, Chapter 551, Texas
Government Code, as amended.
0112.1404;00295729
Alternative 1.
By motion duly made, seconded and passed with an affirmative vote of all the
Council members present, the requirement for reading this ordinance on two separate
days was dispensed with.
READ, PASSED, and ADOPTED on first reading this (OM' day of
N7r/ L. ,2014.
Alternative 2.
READ and APPROVED on first reading this the day of
2014.
READ, APPROVED and ADOPTED on second reading this the day of
, 2014.
ATTEST:
PI
ALAN MCGRAW, Mayor
City of Round Rock, Texas
SARA L. WHITE, City Clerk
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Utility Criteria Manual
EXHIBIT
«A»
SECTION 1 — WATER, REUSE WATER, AND WASTEWATER
Table Of Contents
SECTION I — WATER, REUSE WATER AND WASTEWATER TABLE OF CONTENTS
1.1.0. GENERAL 2
1.2.0 PRIVATE PLUMBING 2
1.2.1. Plumbing Inspections 2
1.3.0. CONSTRUCTION PLAN INFORMATION AND SUBMITTAL REQUIREMENTS 2
1.3.1 General Information 2
1.3.2. Water System Plans 4
1.3.3. Wastewater System Plans 5
1.3.4 Reuse System Plans 7
1.4.0. CONSTRUCTION INSPECTION AND CITY ACCEPTANCE 8
1.4.1. Construction Inspection Procedure 8
1.5.0. LIFT STATION REVIEW, APPROVAL, AND ACCEPTANCE 8
1.5.1 Engineering Report, Plans, and Specifications Review and Acceptance 8
1.5.2. Submittal and Shop Drawing Review 9
1.5.3. City Operation and Maintenance Acceptance 9
1.6.0. ABANDONMENT OF FACILITIES 10
1.6.1. Mains 10
1.6.2. Manholes 11
1.6.3. Lift Stations 11
1.6.4. Service Lines 11
1.7.0. DESIGN REQUIREMENTS FOR WATER, WASTEWATER, AND REUSE WATER
SYSTEMS 11
1.7.1. Introduction 11
1.7.2 Water Systems 12
1.7.3 Wastewater Systems 18
1.7.4. Reuse Water Systems 38
9f4812e9-3a2f-4696-9a56-377b1 a4Obbe1.doc
Utility Criteria Manual
SECTION 1 — WATER, REUSE WATER, AND WASTEWATER
1.1.0. GENERAL
The following information is intended to assist engineers and the general public in the
design and construction of water, reuse water and wastewater facilities. Information
herein is to provide minimum standards for the City of Round Rock (City) requirements
only. Sound engineering judgment shall be exercised to determine if these minimum
requirements must be exceeded for a particular engineering design. All water, reuse
water and wastewater design and construction must comply with the requirements of
the State of Texas, when there is a conflict between State requirements and those
contained herein, the more restrictive shall govern.
1.2.0 PRIVATE PLUMBING
1.2.1. Plumbing Inspections
All private plumbing installations connecting to the City's water, wastewater, and/or
reuse water systems shall be inspected by the Building Inspection Division to insure
compliance with all applicable City ordinances and the latest edition of the International
Plumbing Code adopted by the City Council.
Plumbing installations shall not commence until a permit has been obtained from the
Building Inspections Division and any applicable fee has been paid.
1.3.0. CONSTRUCTION PLAN INFORMATION AND SUBMITTAL REQUIREMENTS
1.3.1. General Information
A. Construction plans for water, reuse water, and/or wastewater installation shall be
submitted to the appropriate City office for acceptance. Acceptance of
construction plans will expire if construction does not commence within two years
from the date of acceptance. Resubmitted plans must include and comply with all
design and construction criteria in effect at the time they are resubmitted.
B. Where appropriate, prior approval of a Municipal Utility District (MUD), Water
Control and Improvement District (WCID) or private utility corporation may be
required.
C. Plans submitted must show approved easements and/or permits on highway
and/or railroad crossings.
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D. A signature on the plans by the appropriate City official constitutes acceptance of
the plans.
E. Plans associated with a site development or subdivision improvement must have
approval from the City Fire Department and the DSO. Plan submittal
requirements must meet the Development Application Packet appropriate to the
submittal type...
F. All water, reuse water and/or wastewater plans will include the following items:
1. Engineer's dated signature and seal of a Professional Engineer licensed in
the State of Texas on each plan sheet.
2. Date of plans and revisions.
3. North arrow and scale shall be shown. The standard horizontal scale shall
be 1" = 50', 40', 20', or 10' (plan view) with respective vertical scale 1" = 5',
4' or 2', or 1' (profiles). Scales used on each plan and profile sheet shall
be the same. For sheets other than plan and profile, a horizontal scale of
1" = 50', 40', 20', or 10' may be used as appropriate. The City may require
a larger-scale be used for plan and profile sheets, or a large-scale blowup
of a particular area.
4. A general location map.
5. Standard City Water and Wastewater construction notes can be found in
the City's Design and Construction Standards (DACS) - General
Guidelines.
6. Indicate on cover sheet all required permit numbers such as development
permit, Texas Department of Transportation (TxDOT) permit, railroad
crossing permit, etc. The project name shall be along the top right hand
border, reading from the bottom of the sheet to the top of the sheet.
7. Volume and page number of recorded easements and any temporary
working space/easements.
8. Size, pipe material and location of main with respect to easements, rights-
of way, and property lines.
9. Property lines and dimensions, legal description, lot and block numbers,
right-of-way dimensions, curbs, sidewalks, pavements, power poles, trees,
and other plan metric features, locations, and street names.
10. Location, vertical and horizontal, size and material of all existing water,
reuse water and wastewater mains, lines and services. The direction of
flow in the wastewater mains shall be indicated.
11. Location, vertical and horizontal, size and description of other utilities
where they may conflict with water, reuse water or wastewater mains or
other service lines shall be shown in both the plan and profile.
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12. Curve data for roads, property lines, water, reuse water and wastewater
lines.
13. Final plat recording or land status report.
14. Street address for all existing structures shall be shown on the lot(s)
where the structures are located.
15. Pressure zone designation for subject tract and zone boundaries where
applicable.
G. The following items may be required prior to plan acceptance:
1. TxDOT permit;
2. Railroad permit;
3. Gas Company permit;
4. Easement acquisition, with volume and page or document number shown
on plans;
5. County approval;
6. Water District approval;
7. MUD approval;
8. Texas Department of Health (TDH) approval;
9. Texas Commission on Environmental Quality (TCEQ) approval;
10. Non -occupancy letter;
11. Service Extension approval; and
12. DSO approvals.
1.3.2. Water System Plans
A. All plan view drawings shall include all applicable items listed in Section 1.3.1.G.
above plus the following:
1. Stations of all proposed connections to existing or proposed water mains.
2. For proposed connections to water mains or facilities to be constructed by
others, identify the project by name and the design engineer.
3. Station numbers for mains shall be identified for beginning points, ending
points, points of curvature, points of tangency, points of reverse curve,
points of intersection, valves, fire hydrants, other appurtenances and
grade breaks.
4. Station numbers shall be identified for the water and reuse water mains
where they cross any other utility.
5. Details of appurtenances shall be shown.
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6. The location of all existing and proposed water services, water mains,
reuse water mains, valves and fire hydrants shall be identified.
7. Ultimate 1% annual chance flood plain limits shall be shown.
8. Design velocity at maximum day plus fire flow and at peak hour.
9. Calculated design pressure at highest and lowest lot served shall be
shown. These pressures shall be a minimum of thirty five (35) pounds per
square inch (psi) at peak hour demand and a maximum of one hundred
ten (110) psi static pressure.
10. Thrust restraint, when required, shall be noted on the plan.
11. Retaining walls, including geogrid, straps, tiebacks and all other
components.
12. Culverts, bridges and other drainage structures.
B. A profile view shall be provided for all water mains twelve (12) inches in diameter
and larger, unless the water main is to be built as a part of a site or subdivision
plan, in which case a profile view shall be provided for all water mains eight (8)
inches in diameter and larger. The profile must show all applicable items listed in
the Design and Construction Standards General Guidelines plus the following:
1. The existing ground profile, proposed finish grade, and subgrade, if under
pavement.
2. Station numbers and elevations of all utility crossings.
3. Station numbers and soil geology information at stream crossings to
evaluate the need for special surface restoration.
4. Identify pipe size, percent grade and pipe material to be used including
American Society for Testing and Materials (ASTM) and/or AWWA
designation. If an alternate material is to be allowed, both should be listed
(example "D.I., Class 150 or PVC, Class 150").
5. Station numbers and elevations for starting points, ending points, point of
intersection, grade breaks, valves, fire hydrants, air release valves,
pressure/flow regulating valves and at intermediate points not exceeding
fifty (50) feet.
6. Retaining walls, including geogrid, straps, tiebacks and all other
components.
7. Culverts, bridges and other drainage structures.
1.3.3. Wastewater System Plans
A. All plan view drawings shall include all applicable items listed in Section 1.3.1.G.
above plus the following items:
1. Station numbers at all proposed connections to existing or proposed
wastewater mains.
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2. For proposed connections to wastewater mains or facilities to be
constructed by others, identify the project name and the design engineer.
3. The location, alignment and structural features of the wastewater main,
including manholes and concrete retards, if applicable.
4. Station numbers for beginning points, ending points, manholes, clean-outs
and other appurtenances.
5. Details of all required appurtenances.
6. Location of all existing and proposed wastewater services, mains and
manholes.
7. Ultimate 1% annual chance flood plain limits.
8. Retaining walls, including geogrid, straps, tiebacks and all other
components.
9. Culverts, bridges and other drainage structures.
B. A profile view shall be provided for all wastewater mains and shall include all
applicable items listed in Section 1.3.1.G. above, plus the following:
1. The existing ground profile, proposed street finish grade and subgrade, or
finished grade if not under pavement.
2. Station numbers and elevations of all utility crossings.
3. Station numbers and soil geology information at stream crossings to
evaluate the need for special surface restoration.
4. Identify the pipe size, percent grade and pipe material to be used including
ASTM and/or AWWA designation. If an alternate material is to be
allowed, both should be listed (example "DI Class 150 or PVC DR 150").
5. Station numbers and elevations for starting points, ending points,
manholes, clean-outs and at intermediate points not exceeding fifty (50)
feet.
6. Elevations shall be indicated on the profile showing the finish floor
elevations of all existing structures. If the structure has an active septic
tank or other disposal system, the flow line elevation of the plumbing
where it exits from the structure is to be indicated. If a lot or tract is
vacant, side shots may be required from the middle of each lot to ensure
gravity service is possible from the lot to the main.
7. Design flows, minimum and maximum, and flow velocities at minimum and
maximum dry weather flows.
8. Retaining walls, including geogrid, straps, tiebacks and all other
components.
9. Culverts, bridges and other drainage structures.
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1.3.4 Reuse System Plans
A. All plan view drawings shall include all applicable items listed in Section 1.3.1.G.
above plus the following:
1. Stations numbers at all proposed connections to existing or proposed
reuse water mains.
2. For proposed connections to reuse water mains or facilities to be
constructed by others, identify the project by name and the design
engineer.
3. Station number for mains shall be identified for beginning points, ending
points, points of curvature, points of tangency, points of reverse curve,
points of intersection, valves, other appurtenances and grade breaks.
4. Station numbers shall be identified for the reuse water mains where they
cross any other utility.
5. Details of appurtenances shall be shown.
6. The location of all existing and proposed reuse water services, water
services, reuse water mains, water mains, valves, and fire hydrants shall
be identified.
7. Ultimatel % annual chance flood plain limits shall be shown.
8. Design capacities and velocities shall be shown.
9. Calculated pressure at highest and lowest possible service connections
shall be shown. These pressures shall be a minimum of thirty five (35)
pounds per square inch (psi) and a maximum of one hundred ten (110) psi
static pressure.
10. Thrust restraint, when required, shall be noted on the plans.
11. Retaining walls, including geogrids, straps, tiebacks and all other
components.
12. Culverts, bridges and other drainage structures.
B. A profile view shall be provided for all water mains twelve (12) inches in diameter
and larger, unless the water main is to be built as a part of a site or subdivision
plan, in which case a profile view shall be provided for all reuse water mains
eight (8) inches in diameter and larger. The profile must show all applicable items
listed in the Design and Construction Standards General Guidelines plus the
following:
1. The existing ground profile, finish grade and subgrade, if under pavement.
2. Station numbers and elevations of all utility crossings.
3. Station numbers and soil geology information at stream crossings to
evaluate the need for special surface restoration.
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4. Identify pipe size, percent grade and pipe material to be used including
American Society for Testing and Materials (ASTM) and/or AWWA
designation. If an alternate material is to be allowed, both should be listed.
5. Station numbers and elevations for starting points, ending points, points of
intersection, grade breaks, valves, fire hydrants, air release valves,
pressure/flow regulating valves and intermediate points not exceeding fifty
(50) feet.
6. Retaining walls, including geogrids, straps, tiebacks and all other
components.
7. Culverts, bridges and other drainage structures.
8. Identify "purple pipe" for PVC piping or "purple wrapped" for DI and Steel
piping.
1.4.0. CONSTRUCTION INSPECTION AND CITY ACCEPTANCE
1.4.1. Construction Inspection Procedure
A. Prior to commencement of any construction, the developer or his/her design engineer
shall attend a Pre -Construction Conference between the City, himself, the Contractor,
other utility companies, any affected parties and any other entity the City may require.
To schedule a Pre -Construction Conference, the developer or his/her design engineer
should contact the appropriate City department.
1.5.0. LIFT STATION REVIEW, APPROVAL, AND ACCEPTANCE
1.5.1. Engineering Report, Plans, and Specifications Review and Acceptance
Acceptance of plans shall expire two (2) years from the date of acceptance. If
construction has not commenced on the facility within two (2) years of the acceptance
date, plans must be resubmitted for acceptance and must include and comply with all
design and construction criteria in effect at the time resubmitted.
A. Prior to design, three (3) copies of a detailed engineering report shall be
submitted to the City for review and approval of the lift station and all related line
work. The engineering report shall include the following:
1. Justification for the proposed lift station. The report must clearly show that
gravity lines are not available or are not economically feasible and that the
number of lift stations has been minimized. This justification must include
a cost benefit analysis of gravity versus lift station project including thirty
(30) years of operation and maintenance of the proposed system.
2. A master development plan for the service area of the proposed lift station
shall be prepared. This plan shall include a map showing the location of
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the lift station, the service area topographic information with two feet
contours, the boundaries of the drainage basin, and the location of the
nearest existing wastewater interceptor within that basin.
3. Engineering calculations and data described in Sections 1.7.3.A. and
1.7.3.H. shall be contained in the engineering report.
4. The City must approve the Engineering Report prior to the developer
beginning preparation of the plans and specifications.
5. TCEQ approval of the lift station is required prior to City approval.
B. All plans and specifications for lift stations within the City's ETJ, submitted for
review and acceptance, must demonstrate compliance with current City Water
and Wastewater Utility Design Criteria and standard lift station specifications.
Acceptance of the lift station plans and specification does not imply the City will
accept the lift station for operation and maintenance (Refer to 1.5.3.).
1. Within the Water and Wastewater Impact Fee Service Area as defined in
Section 1.2.1 of this Manual, the following type of lift stations may be
submitted for review and acceptance:
a. Submersible or grinder pump facilities with rated horsepower no
greater than twenty-five (25) Brake Horse Power (BHP) for the largest
pump.
b. For installation with a required rated horsepower motor greater than
twenty- five (25) BHP the City prefers wet/dry well type installation.
However, submersible non -clog pump facilities with a rated
horsepower of between twenty-five (25) BHP and fifty (50) BHP may
be considered on a case-by-case basis. The Engineer must submit
cost comparisons for submersible versus wet/dry well installations. The
cost comparison should include initial station costs, pump replacement
costs, installation costs and all operational and maintenance cost
including energy costs over the life of the station. The comparison
should assume a typical service life for submersible pumps.
1.5.2. Submittal and Shop Drawing Review
Once the engineering report, plans and specifications have been accepted, at least
three (3) complete sets of submittals and construction plans shall be provided to the
City. These submittals shall contain complete detailed information and drawings for all
lift station equipment and components.
1.5.3. City Operation and Maintenance Acceptance
The City may accept a lift station with a firm pumping capacity greater than twenty-five
(25) gallons per minute (gpm) for operation and maintenance provided the following
conditions are met:
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A. The station is located within the City's approved wastewater service area and
wastewater impact fees are collected for the area served by the lift station area.
B. The lift station has been inspected and determined to be constructed in
conformance with the City and TECQ requirements. Any lift station not
conforming to City standards shall be upgraded to City standards before the City
will accept the lift station for operation and maintenance.
C. The owner or his representative has provided all information requested in
Sections 1.5.1. and 1.5.2. above, including five (5) complete sets of all final
Operations and maintenance (O&M) Manuals for all equipment installed with the
lift station, and has received City acceptance. The O&M Manuals should describe
the general operations of the equipment and provide information on the proper
maintenance procedures to be performed on the equipment.
D. The owner has granted the City a wastewater easement for the lift station and all-
weather access road. A copy of the recorded easement plat, legal description
and any other legal documents granting the easement shall be delivered to the
City. The easement shall extend to at least five feet outside the lift station fence
and shall include an all-weather access road with turn -around areas that extend
back to paved public right-of-way. This easement shall be separate and in
addition to any necessary pipeline easement.
If the lift station is to become a permanent installation, transfer of ownership and
title to the land may be required by the City prior to acceptance of the station for
operation and maintenance.
E. Additionally, a letter of assignment shall be written to the City from the owner
transferring title of the lift station and related equipment to the City. This letter
shall be delivered to the City before acceptance of the lift station for operation
and maintenance. The original owner may regain title to a temporary lift station
that was designed and constructed entirely at his expense and for which no
refund was made by the City. After written notification by the City that the lift
station has been abandoned, the original owner has one (1) month to notify the
City in writing of his intent to regain title to the lift station.
F One (1) complete set of reproducible Mylar of the as -built drawings and a copy of
the file in electronic format as specified by the City shall also be provided to the
City prior to acceptance of the lift station for operation and maintenance.
1.6.0. ABANDONMENT OF FACILITIES
If a new project will result in the abandonment of existing facilities, the plans shall
provide for the appropriate abandonment of these facilities.
1.6.1. Mains
Abandonment of wastewater mains in private easements shall include the filling in the
main with a flowable fill or slurry and meeting requirements of the current
specifications. Plans should include method of abandoning all other wastewater mains.
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1.6.2. Manholes
The abandoned manholes shall be removed to a level not less than two (2) feet below
grade, including the entire cone section. Inlets and outlets shall be securely plugged,
with grout for a minimum of 12" beyond the outside wall of the manhole and the
structure filled with stabilized sand or granular material that is no greater than 1-1/2"
maximum size.
1.6.3. Lift Stations
Abandonment of lift stations shall the removal of all pumps, motors, couplings, valves,
and controls from the dry well and all appurtenances above finished grade. Both the
wet well and dry well shall be cut down four (4) feet below grade, filled with cement
stabilized sand, and covered with top soil to grade. The associated force main shall be
properly abandoned (see 1.6.1 above). This includes cutting and plugging both ends
and/or grouting main as appropriate.
All disturbed areas shall be re -vegetated. The City shall be notified prior to
abandonment.
1.6.4. Service Lines
All water service lines, including fire lines that are being abandoned and not transferred
to a new distribution line shall be disconnected at the corporation stop or valve. Valve or
corporation stop shall be closed, plugged, and covered with concrete thrust blocking.
All other valves and appurtenances should be removed.
1.7.0. DESIGN REQUIREMENTS FOR WATER, WASTEWATER, AND REUSE
WATER SYSTEMS
1.7.1. Introduction
These guidelines are intended to establish the minimum basic design requirements for
water, reuse water and wastewater systems within the City and its ETJ, but do not
include water, reuse water, and wastewater treatment plants.
The following information is provided to assist engineers and the general public in the
design and construction of water and wastewater facilities within the City's ETJ. All
plans for such facilities shall be prepared by or under the supervision of a Professional
Engineer, licensed in the State of Texas. It will be the responsibility of the engineer to
ensure that the plans are in compliance with the latest versions of all applicable federal,
state and local ordinances, rules and regulations.
These include, but are not limited to, the following:
A. Design Criteria for Sewage Systems - TCEQ.
B. Rules and Regulations for Public Water Systems - TCEQ.
C. Edwards Aquifer Rules - TCEQ
D. The Subdivision Ordinance and Utility Ordinances of the City.
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E. City DACS - Standard Specifications Manual.
F. City DACS - Water and Wastewater Utility Design Criteria.
G. State of Texas Board of Professional Engineers
The design engineer shall prepare construction drawings in conformance with City
requirements and accepted engineering practice, but also with consideration of future
maintenance and operational concerns.
The following are specific criteria the design engineer shall use in his/her design.
Where conflict exists between State or Federal codes and City criteria, the more
restrictive shall govern. The criteria below are intended as a guide for the design
engineer and are not intended to be an exhaustive list. All items may not apply in all
cases.
1.7.2 Water Systems
Plans shall be submitted and sealed by a Professional Engineer licensed by the State of
Texas which will certify that the system has been designed in accordance with the
requirements set forth below and conform to the rules, regulations, and requirements
established by the TCEQ Design Criteria in Chapter 290 of the Texas Administrative
Code, as amended.
A. Size/Capacity Determination
1. General
a. Hazen Williams Friction Coefficient C = 110, higher C coefficient may
be used for new mains only upon approval by the City with sufficient
documentation to show effects of long-term use.
b. Average day demand = two hundred three (203) gal/person/day
c. Peak day demand = four hundred six (406) gal/person/day
d. Peak hour demand = eight hundred ninety three (893) gal/person/day
e. Maximum static pressure — one -hundred (100) psi unless otherwise
approved by the City (fire hydrants will have attached a pressure -
reducing valve (PRV) where pressure exceeds one -hundred ten (110)
psi)
f. If the maximum static pressure exceeds eighty (80) psi, a PRV will be
required on the property owner's side of the water meter and should be
shown on the plan view.
g. Minimum operating pressure is fifty (50) psi at the highest elevation
meter location using average day demand.
2. Peak Hour Demand Requirements
a. The maximum allowable velocity shall not exceed eight (8) feet per
second (fps).
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b. The minimum pressure at any point in the affected pressure zone must
not be Tess than thirty-five (35) psi.
3. Emergency Demand (Fire Flow) Requirements
a. The maximum allowable velocity shall not exceed ten (10) fps.
b. Fire flow (reference International Fire Code 2012, as amended)
requirements will be determined in accordance with the City Fire Code
and associated rules.
c. The minimum residual pressure at any point in the affected pressure
zone at peak day plus fire flow must not be less than twenty (20) psi.
4. Sizing of Water Mains
All water mains shall be installed in accordance with the Water Master
Plan adopted by the City. Computer modeling is preferred for sizing water
mains. However other engineering calculation methods may be used to
size water mains that are less than sixteen (16) inches in diameter.
(However, no water main and/or fire main shall be sized smaller than the
diameter shown in the City's Water Distribution System Master Plan or as
determined utilizing the City's Water Distribution System Computer
Model.) The largest size, as determined by comparing the service area's
peak hour demand and peak day plus fire flow demand, shall be used. All
water mains shall be sized to provide necessary service to the tract being
developed. The City may require oversizing of certain mains in
accordance with City ordinances.
5. Storage Requirements
If it is determined by the City that additional storage is required, the
following criteria shall be used:
Effective Storage = 100 gal/person
Emergency Storage = 100 gal/person
TOTAL STORAGE = 200 gal/person
Effective Storage is defined as storage that will provide a minimum of fifty
(50) psi of pressure at the highest service elevation in pressure zone.
The Engineer may be required to provide computer simulations as
determined on a case-by-case basis.
B. Mains
1. Minimum main size shall be eight (8) inches unless the City approves a
smaller size. Provision must be made for a flush valve at the end of dead
end mains. The minimum size for any street type, however, will be
governed by various factors which include fire protection requirements,
high density land usage, and the designer's consideration of general
system gridding, future transmission mains, neighboring developments
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and area configuration. Looped systems with more than one feed are
required for service reliability wherever possible. Intervening valve
placement is required for looped systems, unless otherwise approved by
the City. Transmission line sizes will be determined on a case-by-case
basis, if not already identified in the City's Water Distribution System
Master Plan.
2. Three (3) inch, ten (10) inch, fourteen (14) inch, and other non-standard
pipe sizes shall not be allowed for use as typical water mains.
3. All water mains, eight (8) inches in diameter and larger, shall be profiled
unless it can be shown that conflicts with other utilities do not exist.
4. Water mains shall be located where maintenance can be accomplished
with the least interference with traffic, structures, and utilities.
5. The separation between water and wastewater mains must comply with
TCEQ rules or have a variance approved by the TCEQ before submittal to
the City. Water mains shall be installed with a minimum of eighteen (18)
inches clearance from other utility and drainage lines.
6. Standard assignment for water mains shall be one (1) foot inside the right-
of-way line or in an easement) and on the high side of the street according
to natural topography unless otherwise accepted by the City. The latter
requirement may be relaxed if it is demonstrated and the City agrees there
is one or more compelling reasons to assign a main on the low side of a
street (i.e. numerous crossings are avoidable, maintenance is facilitated,
onerous costs to construct, etc.)
Unless otherwise approved by the City, mains shall be located within a
public right-of-way or within a recorded easement. Main assignments in
City streets must be approved by the City. Mains in county roads must
also be approved by the County.
7. Piping materials and appurtenances shall conform to the City's DACS and
the Standard Specifications Manual.
8. Minimum depth of cover over the pipe and all appurtenances shall comply
with City's Standard Details; maximum depth will be as approved by the
City for the specific materials, application and conditions. Water mains
shall be kept at reasonable depths (three and one half foot to four foot (3
1/2' to 4') cover in unpaved areas and a minimum of thirty (30) inch cover
below sub -grade in paved areas). Where possible, water crossings under
other utilities shall be prohibited, except where express consent is granted
by the City. Such acceptance shall be based on detailed plans and
exhibits that adequately explain and demonstrate the crossing.
Encasement pipe shall be provided under permanent structures, such as
storm water boxes, culverts, and any pipe forty-two (42) inches in
diameter and larger. Concrete encasement of pipe shall be avoided.
14
Concrete trench caps above bedding are generally acceptable for creek or
stream crossings.
9. For mains twelve (12) inches and larger, drain valves shall be placed at
low points, (i.e. fire hydrant or flush valves).
10. All fire sprinkler supply lines shall have a gate valve on the line at the
connection to the main line and a backflow preventer inside the property
line, but accessible for inspection by City personnel. All un -metered fire
lines shall have a City approved flow detection device. Sprinkler supply
lines exceeding 65 feet in length must have an approved backflow
prevention device located as close to the beginning of the line as possible.
11. The design engineer is responsible for determining when air/vacuum
release valves are required and the size required. On water mains 12
inches in diameter and larger, automatic air release valves will be placed
at all high points and at the down-slope side of all valve locations.
Automatic air/vacuum and vacuum release valves shall be approved on a
case-by-case basis.
12. All pipe and accessories shall be of new materials only. Water mains shall
be Ductile Iron (AWWA C-110, C-104 and ANSI/AWWA C -153/A21.53-84,
min. pressure Class 150) or PVC (AWWA C -900/C-905, ASTM F477 and
D3139, min. pressure Class 150), or HDPE (AWWA C-906, ASTM F714,
NSF 61 and PE 3408 by ASTM 3350) with a minimum 11 dimension ratio
(DR). Service piping shall be copper or polyethylene as accepted by the
City. Minimum size of service lines shall be as follows:
Dwelling Units
Minimum Line Size
1
1"
2
1.5"
3-6
2"
7-11
4"
12-75
6"
More Than 75
8"
13. Double services shall be provided as often as possible to minimize the
number of service lines to be maintained in the future and reduce time
required for future meter reading. Service lines under pavement shall be
placed, according to the most current City detail.
14. Water mains between residential lots, crossing blocks, shall be avoided.
Water mains between residential lots may be allowed if the purpose is to
prevent the creation of a Dead End Main and approved by the Director
of Utilities. Water mains along the rear of residential lots, through back
15
yards, shall be prohibited. Utility or easement Tots may be appropriate in
some cases.
15. Placing water mains within state right-of-ways shall be prohibited unless
such is specifically approved by the City. Water lines in easements
abutting the state right-of-way are allowed, provided easements are
unobstructed and accessible.
16. Water mains and fire hydrant leads will be allowed in easements, if it can
be demonstrated that the easement will be unobstructed and accessible,
and that the water main or fire hydrant leads will be a minimum of fifteen
(15) feet from any structure. Minimum easement width shall be fifteen
(15) feet and an additional two (2) feet of easement width provided for
every one foot of depth of cover greater than seven (7) feet. Minimum
easement between residential lots shall be thirty (30) feet.
17. Meter boxes/vaults shall be reviewed and approved by the City.
18. Under no circumstances shall more than thirty (30) Living Unit
Equivalents (LUEs) be served by a single water main feed.
19. Wherever possible, a looped water system shall be provided and dead-
end mains will be minimized. Dead-end mains must be approved by the
City. All dead-end mains exceeding 65 linear feet in length will require
an approved backflow prevention device located as close to the
beginning of the dead-end main as possible.
C. Valves
1. There shall be a valve restrained to the main tee of each fire hydrant.
These and all valves shall be resilient wedge gate valves, unless the City
approves the use of butterfly valves at specific locations. In lines thirty six
(36) inches and larger, butterfly valves may be used except in areas
described below where resilient wedge gate valves are specifically
required.
2. Valves shall be located at the intersection of two (2) or more mains and
shall be spaced so that no more than thirty (30) customers will be without
water during a shutdown. For lines smaller than twenty-four (24) inches,
typical spacing should be five hundred (500) linear feet in high-density
areas and twelve hundred (1,200) linear feet in a residential area, with a
maximum spacing of one thousand five hundred (1,500) linear feet. For
mains twenty four (24) inches to thirty (30) inches a valve shall be installed
at intervals not to exceed two thousand (2,000) linear feet. For lines thirty-
six (36) inches and larger, valve spacing shall not exceed two thousand
five hundred (2,500) linear feet.
3. At dead end water mains that will be extended in the future, gate valves
shall be located one (1) pipe length, with a twenty (20) foot minimum, from
16
the end points (restrained plug) of the main. In lines larger than sixteen
(16) inches, gate valves shall be resilient wedge gate valves. The
Engineer shall provide and show drawings for complete restraint for all
such valves, pipe extensions and end plug.
4. Branch piping, both new and future branches shall be separated from the
main with gate valves. In branches larger than sixteen (16) inches these
shall be resilient wedge gate valves.
5. For mains twelve (12) inches and smaller, valves at street intersections
shall be located at opposite point of curvature (p.c.) of the curb line.
6. All valves from six (6) inches to thirty (30) inches shall be gate valves.
Gate valves shall be located on each side of a tee or cross (i.e. each tee
will require three (3) gate valves and each cross will require four (4) gate
valves to be installed). Variations from these requirements require
approval by the Director of Utilities.
7. The operating nut of any valve shall be between eighteen (18) inches and
30 twenty four (24) inches below finished grade. Extensions of valve nuts
shall be provided as necessary to meet the depth requirement. Extensions
shall not be fixed to operating nut.
8. Valves with valve extensions and those at pressure zone boundaries shall
be equipped with a locking type debris cap.
9. All gate valves and butterfly valves shall be installed in accordance with
the City's Standard Details. Horizontal installation of gate valves is strictly
prohibited.
10. Valves having "push on" joints are not permitted for fire hydrant leads and
laterals.
11. Valve stem riser cans shall be raised above natural grade in unpaved
areas and the City may require a metal sign to indicate the valve's
location.
D. Fire Hydrants
1. Fire hydrants shall be placed at a maximum of five hundred (500) foot
intervals along residential streets and a maximum of three hundred (300)
foot intervals along mercantile streets. Specific fire hydrant locations
within a commercial, industrial, or multi -family site shall be coordinated
with the City Fire Department. Consideration shall be given to
accessibility and functionality of position when locating fire hydrants and
such consideration could shorten the above stated spacing as required by
the City. Fire hydrants shall be in conformance with AWWA specifications
with National Standard Threaded (NST) outlets suitable for use with City
fire protection equipment.
2. If required by the City, fire hydrants shall be installed on both sides of all
divided road/highways. Roads/highways where opposing lanes of traffic
17
are separated by a vertical obstruction shall be considered a divided
road/highway.
3. For dead-end mains with no fire hydrant, an acceptable flushing device is
required.
4. No private fire hydrants shall be allowed.
5. The entire fire hydrant assembly shall conform to the City's Standard
Details.
E. Services
1. Water services shall be constructed in accordance with the City's
Standard Details. More than two meters on a single service line will be
considered on a case-by-case basis.
2. Individual meter services will not be taken from transmission lines.
Transmission lines are generally considered to be twenty-four (24) inches
in diameter or larger. Exceptions must be approved by the City at the time
of plan submittal. The design Professional Engineer shall submit a letter
with this request.
F Water Meters for Multi -Family and Commercial Customers
Master meters are prohibited for multi -family, manufactured home, rental
community, commercial property, or any other multiple -use facility, unless
otherwise approved by the City in the original development process. Each
individual building must be individually metered and located in an appropriate
easement to allow the City to access and work on the meter assembly. The
measurement of the quantity of water, if any, consumed by the occupants of
individual units shall be provided by the following:
1. Sub -meters, owned by the property owner or manager, for each dwelling
unit or rental unit.
2. An alternative method approved by the City.
1.7.3 Wastewater Systems
Connection with a TCEQ approved sanitary sewer system shall be required except
where the City determines that such connection would require unreasonable
expenditure of funds when compared with alternate methods of sewage disposal.
Where alternate sewage disposal is permitted, the plans for such system must meet the
requirements of the City, the TCEQ, and be approved by the Williamson or Travis
County Health Department, whichever is appropriate, prior to approval of the final plat
by the Planning and Zoning Commission.
Developers shall install all wastewater mains and lines necessary to serve each lot in an
entire subdivision, addition, or site development project. The Developer shall install
necessary on-site and off-site sanitary sewer mains and shall extend service to all lots,
terminating each service with a cap. For the orderly extension of wastewater lines as
established in the City's Water and Wastewater Master Plan, maintained by the City.
18
Developers shall install wastewater mains to the boundaries of their development for
future connection by the development of the abutting land. Services from multi -family
and non-residential lots shall connect at manholes.
Any wastewater collection system connecting to the City's wastewater collection
system, whether public or private, shall be designed and constructed in accordance with
the standards and specifications, herein.
The design engineer shall include a statement with the wastewater system plans that
the wastewater system meets the requirements set forth herein and complies with the
rules and regulations established by the TCEQ in Chapter 217 (Design Criteria for
Sewage Systems) and Chapter 213 (Edwards Aquifer Rules) of the Texas
Administrative Code, as amended.
A. Determination of Wastewater Flow
1. Residential single-family units (one LUE equals one (1) single family unit)
shall be assumed to produce an average wastewater flow of two hundred
and eighty (280) gallons/day.
2. Industrial/commercial wastewater flows will be determined by the City on a
case-by-case basis in conjunction with information supplied by the design
engineer.
3. Inflow and Infiltration (I/1)
In sizing wastewater mains, external contributions are accounted for by
including seven hundred fifty (750) gallons per acre per day served for
inflow and infiltration. For wastewater mains in the Edwards Aquifer
Recharge Zone, refer to the TCEQ requirements. Strict attention shall be
given to minimizing inflow and infiltration.
4. Peak Dry Weather Flow (PDWF)
PDWF is the peak wastewater flow from the LUEs that are contributing to
the sewer system, excluding inflow from surface water or infiltration of
ground water. The PDWF is derived from the formula:
Qpdwf = ([18+(0.018 x F)0•5]/4+(0.018 x F)0.5) x F
Where: F = 80 gal./person/day x No. of LUEs x 3.5/1440 = average dry -
weather flow in gpm
5. Peak Wet Weather Flow (PWWF)
The Peak Wet Weather Flow is obtained by adding inflow and infiltration to
the PDWF. In designing for an existing facility, flow measurement shall be
used in lieu of calculations for the pre-existing developed area.
6. Minimum Flow.
The minimum flow is derived from the formula:
Qmin. = [0.2 (0.0144 x F)0.198] x F
19
B. Determination of Pipe Size
1. Minimum Size.
All wastewater mains shall be installed in accordance with the City's
Wastewater Master Plan. All wastewater mains shall be sized to provide
necessary service to the tract to be developed. The minimum diameter of
all gravity sewer mains shall be eight (8) inches. For service line sizes,
refer to the City's Standard Details. The City may require oversizing of
certain mains in accordance with City ordinances.
2. Design Requirements.
For sewer mains, fifteen (15) inches in diameter or smaller, use the larger
size as determined below:
a. The main shall be designed such that the PDWF shall not exceed
sixty-five (65) percent of the capacity of the pipe flowing full.
b. The main shall be designed such that the PWWF shall not exceed
eighty-five (85) percent of the capacity of the pipe flowing full.
c. For sewer mains, eighteen (18) inches in diameter or larger, the main
shall be designed such that the PWWF shall not exceed eighty (80)
percent of the capacity of the pipe flowing full. Full flow shall mean the
capacity of a pipe that has a depth of flow equal to the pipe diameter,
and the hydraulic grade is at the inside top of the pipe.
3. Design Velocities
The minimum design velocity calculated using the PDWF shall not be less
than two (2) feet per second (fps). The maximum design velocity
calculated using the PWWF should not exceed ten (10) fps. Velocities in
excess of ten (10) fps may be considered under special conditions where
no other options are available. In such cases, proper consideration shall
be given to pipe material, abrasive characteristics of the wastewater flows,
turbulence and displacement by erosion or shock.
4. Minimum Slope
The minimum slope for mains within the service area of the City shall be
as shown on the following table. Flatter grades may be approved on a
case-by-case basis by the City for mains in excess of eight (8) inches in
diameter.
City of Round Rock Minimum and Maximum Pipe Slopes
Size of Pipe Minimum Slope Maximum Slope
(inches) (%) (%)
6 0.50 12.35
8
0.40 8.40
20
10 0.30 6.23
12 0.25 4.88
15 0.20 3.62
18 0.11 2.83
21 0.09 2.30
24 0.08 1.93
27 0.06 1.65
30 0.055 1.43
33 0.05 1.26
36 0.045 1.12
39 0.04 1.01
>39 * *
*For pipes larger than 39 inches in diameter, the slope is
determined by Manning's formula to maintain a velocity
greater than 2.0 feet per second and less than 10.0 feet
per second when flowing full.
Manning's Formula
1.49
V = x R.167xVs
?Z
Where:
V = velocity (ft. /sec)
n = Manning's roughness coefficient (0.013)
Rh = hydraulic radius (ft.)
S = Slope (ft. /ft.)
C. Design Considerations
1. Materials and Standards
All materials and appurtenances shall conform to the City standards.
Gravity wastewater mains shall be eight inch (8) minimum and constructed
of PVC (ASTM D 3034, SDR -26 or less), HDPE (AWWA C-906, ASTM
F714, NSF 61 and PE 3408, 3608, or4710 by ASTM 3350, or as
amended) with a minimum 13.5 dimension ratio (DR), Ductile iron pipe
size (AWWA C-110), Fiberglass (ASTM D3262), or PVC (ASTM D3212
and A2026) "double wall" or other equivalent as approved by the City.
21
Gravity wastewater services shall be six (6) inches minimum and
constructed of PVC (ASTM D 3034, SDR-26 or less) unless otherwise
accepted by the City. All wastewater mains shall be profiled.
2. Protecting Public Water Supply
No physical connection shall be made between a drinking water supply
and a sewer or any appurtenance thereof. An air gap of a minimum of two
inlet pipe diameters between the potable water supply and the overflow
level connected to the sewer shall be provided.
3. Location
The location of the wastewater main shall be in conformance with the
City's Standard Details. The City must approve alternative assignments.
Outside the city limits, the design engineer shall coordinate utility
assignments with the City and other appropriate authority.
Standard assignment for wastewater mains shall be five (5) feet off the
street centerline opposite from water, unless the City determines that an
alternate location is acceptable.
4. Separation Distance
The separation between wastewater mains and other utilities shall be in
accordance with the rules and regulations adopted by the TCEQ.
Wastewater mains and services shall be installed with a minimum
clearance of eighteen (18) inches from other utility or drainage lines.
5. Steep grades
Where the pipe grade exceeds twelve (12) percent, concrete retards
conforming to the City standards will be required at intervals of no more
than twenty-five (25) feet (preferably at joint locations) around the exterior
of the pipe within the bedding envelope.
6. Depth of Cover
The minimum depth of cover over the upper-most projection of the main
shall comply with the City's Standard Details; the maximum depth shall be
as approved by the City for the specific material, application and
conditions. The design Engineer should strive to keep wastewater mains
in streets at reasonable depths, eight (8) feet from the top of the pavement
to the flow line. Excessively deep wastewater mains, greater than twelve
12 feet, shall be avoided, unless otherwise accepted by the City. When
wastewater mains will be more than twelve (12) feet deep from the flow
line to the top of the finished surface and services to the main are
required, an alternate method of intercepting services or alternate service
design shall be provided. For example, a parallel line that is laid at a
shallower depth might be designed to pick up services and the line tied to
the deep main at one (1) or more practical locations. Encasement pipe
22
shall be provided under permanent structures. Concrete encasement
shall be avoided.
7 Easements
Wastewater mains along the rear of residential lots, continually through
back yards, between residential Tots and crossing blocks shall be
prohibited, except when determined by the City to be unavoidable. .
When determined to be unavoidable, such mains shall be laid along a
straight alignment, absent of curves, jogs, and manholes when traversing
between lots, with manholes provided at every intersecting street.
Excessive depths of mains in easements shall be avoided. Easements
shall be a minimum of fifteen (15) feet in width with an additional two (2)
feet of easement width for every one (1) foot of depth over eight (8) feet.
Utility or easement lots may be appropriate in some cases.
8. Turbulence
Wastewater lines and manholes shall be designed to minimize turbulence
to prevent release of sulfide gases.
D. Manholes
1. Manholes shall be located and spaced so as to facilitate inspection and
maintenance of the wastewater main. Manholes shall be placed at the
following locations:
a. Intersections of mains.
b. Horizontal alignment changes.
c. Vertical grade changes.
d. Change of pipe size.
e. Change of pipe material.
f. The point of discharge of a force main into a gravity wastewater main.
g. Intersection of service lines to main lines twenty-four (24) inches and
larger.
h. At the point of connection of a building service line to the public
wastewater service stub for multi -family projects exceeding fifteen (15)
dwelling units and for commercial developments (containing more than
four thousand (4,000) square feet) requiring a water meter greater than
two (2) inches.
2. Manholes shall be reinforced concrete and conform to the City's Standard
Details.
3. Connections to existing manholes shall be made by coring and conform to
the City's Standard Details.
23
4. Manhole spacing for lines smaller than twenty-four (24) inches shall not
exceed four hundred (400) feet; for larger mains, spacing may be
increased, subject to approval by the City.
5. All manholes not located in paved areas shall have watertight covers
bolted in place.
6. Manholes shall be constructed of or lined with a corrosion resistant
material. Where new construction ties into an existing manhole, the
existing manholes must be lined, coated, or replaced with a corrosion
resistant material. If the existing manhole is in poor condition, the
manhole must be repaired or replaced prior to lining or coating.
7 All lines into manholes, including drop connections, shall match crown -to -
crown where feasible. Any deviation must be approved in advance by the
City.
8. Drop manholes will have a maximum of eight (8) foot of drop and require
City approval where the main size exceeds fifteen (15) inches.
9. Manholes shall have the following minimum sizing:
a. Forty-eight (48) inches for mains eighteen (18 inches in diameter or
smaller.
b. Sixty (60) inches for mains larger than eighteen (18) inches and
smaller than thirty (30) inches in diameter.
c. Seventy-two (72) inches for thirty (30) inches in diameter to smaller
than forty-eight (48) inches in diameter.
d. Eighty-four (84) inches diameter for mains forty-eight (48) inches and
larger.
E. Ventilation
Ventilation shall be provided as required by TCEQ rules and regulations.
F. Inverted Siphons
Siphons shall have a minimum of two barrels. The minimum pipe size shall be
six (6) inches with a minimum flow velocity of three (3) fps at peak dry weather
flow. The minimum dry weather flow shall be used to size the smallest barrel.
Three -barrel siphons shall be designed to carry the capacity of the incoming
gravity wastewater mains(s) with one barrel out of service.
An additional corrosion resistant pipe shall be designed to allow for the free flow
of air between the inlet and outlet siphon boxes. The diameter of this air jumper
shall not be smaller than one-half the diameter of the upstream sewer. Air
jumper pipe design shall provide for removal of condensate water that will collect
in the pipe.
24
Siphon inlet and outlet structures shall be manufactured with approved corrosion
resistant material and shall provide for siphon cleaning and maintenance
requirements.
G. Service Lines
Wastewater service lines, between the main and property line, shall have an
inside diameter not Tess than six (6) inches. The minimum grade allowed for
service lines is zero point five (0.5) percent. Service connections made to mains
larger than fifteen (15) inches in diameter shall be considered on a case-by-case
basis. Services into the top of mains, stack -type, shall be prohibited. Services
shall be laid on straight grade from main to point of termination, without
horizontal or vertical bends, unless otherwise approved by the City.
Wastewater services are generally placed along the common property line
between two lots where there is no conflict with other utilities' services or curb
inlets. Domestic water service is generally located at the other lot corner.
Wastewater service should be placed two (2) feet on the right of the common lot
line. Dry utilities are placed two (2) feet left of the common lot line. Services to
lots without a water/wastewater easement may terminate at the property line with
a clean-out; service to lots having a five foot by five foot (5' x 5')
water/wastewater easement may terminate within the easement. For details, see
the City's Standard Details.
Single-family and duplex service connections shall be made with sanitary tees at
a ninety (90) degree intersection with mains. Commercial, multi -family, and
industrial services shall intersect the City system at a manhole.
H. Lift Stations Design Criteria (Excluding Low Pressure Systems)
Lift stations will be allowed only where conventional gravity service is not
feasible. The City may impose additional requirements for individual lift stations
as conditions warrant. Wastewater service facilities within a site or subdivision
shall be designed so as to minimize the number of lift stations needed to serve
the lots.
In addition to these criteria, all lift stations must meet the TCEQ Chapter 217
rules as amended and the provisions of this Manual.
1. Flow Development
Calculation of wastewater flow shall be done in accordance with Section
1.7.3.A. The following calculations shall be included:
a. Maximum Wet Weather Flow (Design Flow)
This flow is used to determine the lift station design capacity. All lift
stations shall be designed to handle the maximum wet weather flow for
its service area.
25
Equation: (Population of service area x 80 gallons per capita per day
(gpcd) x maximum flow peaking factor) + (1000 gallons per acre
served)
b. Maximum Dry Weather Flow
This flow is used to determine pipe size in the collection system.
Equation: (Population of service area) x (80 gpcd) x (maximum
flow peaking factor)
c. Average Dry Weather Flow
This is the flow developed without the maximum flow peaking factor.
This flow is used to determine the average detention time in the wet
well.
Equation: (Population of service area) x (80 gpcd)
d. Minimum Dry Weather Flow
This is used to determine the maximum detention time in the wet well.
Equation: (Population of service area) x (80 gpcd) x (minimum flow
peaking factor)
e. A minimum of two (2) pumps shall be required for all lift station. The
capacity of the pumps shall be such that the maximum wet weather
flow can be handled with the largest pump out of service.
2. Wet Well Design
a. The bottom of the wet well shall have a minimum slope to the intake of
two (2) vertical to one (1) horizontal. There shall be no projections in
the wet well, which would allow deposition of solids.
b. The wet well volume shall be sized to provide adequate storage
volume at peak design flows and a pump cycle time of sufficient
duration to prevent pump short cycling and consequential motor
damage. Pump cycle time, defined as the sum of "pump off' time plus
"pump on" time, shall be as follows:
Motor Horse Power
Minimum Cycle Time In Minutes (0)
2to50
10
51 to 75
15
76 to 250
30
251 to 1500
45
26
Volume between "pump on" and "pump off' elevation (of the pump
cycle) shall be determined by the following criteria:
V = 6q/4
where q = pump capacity in gpm and 6 is the minimum cycle time in
minutes.
c. All "pump on" levels shall have a minimum separation of one (1) foot
between levels. All "pump off' levels shall be at least six (6) inches
above the top of the pump casing. For more than two (2) pumps, the
"pump off' levels shall be staged with a minimum separation of one (1)
foot between levels.
d. An example of a two (2) pump staging sequence follows:
High-level alarm
Lag pump on
Lead pump on
Lag pump off
Lead pump off
Low-level alarm
The high level alarm shall be at least one foot above the last
(highest) "pump on" level in the wet well and also at least one (1)
foot below the flow line of the lowest influent line into the wet well.
For lift stations with three (3) pumps or more, the following method
for calculating the wet well volume may be used:
V=2xg1/4 and K=(q,—q2)+q,
V2 = V'xNxV1
Where: V1 = working volume for the first pump in gallons
6 = minimum cycle time in minutes
co = capacity of the first pump in gpm
q2 = capacity of the second pump in gpm
K = the ratio of the discharge increment to the discharge of
the first pump, without dimensions
V2 = working volume for the second pump in gallons
V' = the ratio of additional draw down volume to the volume
for one pump without dimensions
N = number of pumps
27
1) Calculate V1 and K.
2) Locate K on Table 1 and read the corresponding value for V'.
3) Calculate V2.
f. An example of a three (3) pump starting sequence is as follows:
High-level alarm
Third pump on
Second pump on
First pump on
Third pump off
Second pump off
First pump off
Low Level alarm
For the location of the high level alarm, refer to the example of a two
pump starting sequence.
g. Adequate space should be provided between the bottom of the wet
well at the intake of the pumps.
TABLE 1: V' Values Corresponding To Various Values
K
V'
K
V'
K
V'
0.00
0.00
2.10
1.36
3.49
2.63
0.33
0.00
2.13
1.39
3.53
2.67
0.44
0.01
2.17
1.42
3.57
1.70
0.53
0.04
2.20
1.45
3.61
2.74
0.62
0.08
2.23
1.49
3.65
2.77
0.70
0.12
2.27
1.52
3.69
2.81
0.77
0.16
2.30
1.55
3.73
2.85
0.84
0.21
2.34
1.58
3.77
2.88
0.90
0.25
2.37
1.62
3.81
2.92
0.96
0.29
2.41
1.65
3.85
2.96
1.02
0.34
2.45
1.68
3.89
3.00
1.07
0.38
2.48
1.71
3.93
3.03
28
1.12
0.42
2.52
1.75
3.97
3.07
1.17
0.46
2.55
1.78
4.01
3.11
1.22
0.51
2.59
1.81
4.05
3.15
1.26
0.55
2.62
1.84
4.09
3.18
1.30
0.59
2.66
1.88
4.13
3.22
1.34
0.63
2.70
1.91
4.17
3.26
1.38
0.66
2.73
1.94
4.21
3.30
1.42
0.70
2.77
1.97
4.25
3.34
1.46
0.74
2.81
2.01
4.29
3.38
1.50
0.78
2.84
2.04
4.33
3.42
1.54
0.81
2.88
2.07
4.38
3.45
1.57
0.85
2.92
2.11
4.42
3.49
1.61
0.89
2.95
2.14
4.46
3.53
1.65
0.92
2.99
2.18
4.50
3.57
1.68
0.96
3.03
2.21
4.54
3.61
1.72
0.99
3.07
2.24
4.58
3.65
1.75
1.03
3.10
2.28
4.63
3.69
1.79
1.06
3.14
2.31
4.67
3.73
1.82
1.09
3.18
2.35
4.71
3.77
1.86
1.13
3.22
2.38
4.75
3.81
1.89
1.16
3.26
2.42
4.79
3.85
1.92
1.19
3.29
2.45
4.84
3.89
1.96
1.23
3.33
2.49
4.88
3.93
1.99
1.26
3.37
2.52
4.92
3.97
2.03
1.29
3.41
2.56
4.96
4.01
2.06
1.33
3.45
2.59
5.01
4.05
K = Pump discharge (Dimensionless) V' = Volume (Dimensionless)
Source: ALBERT PINCINE
3. Wet Well Detention Time
a. Calculate the detention time (Td) in the wet well for the maximum wet
29
weather flow, maximum dry weather flow and average dry weather flow
using the following equation:
Td= tf+ te
Where:
tf = (v) _ (i) = time to fill the wet well in minutes
te = (v) _ (q - i) = time to empty the wet well in minutes
V = Volume of wet well between "pump on" and "pump off'
elevations in gallons
q = Pump capacity in gpm
i = flow into the station corresponding to the maximum wet
weather flow maximum dry weather flow or average dry
weather flow in gpm
b. Maximum detention time shall be calculated with i = minimum dry
weather flow.
c. Odor control shall be provided for the wet well, if the total detention
time in the wet well and force main system exceeds 180 minutes.
4. Static Head
The static head shall be calculated for "pump on" and "pump off'
elevations in the wet well.
5. Net Positive Suction Head
The Net Positive Suction Head (NPSH) required by the pump selected
shall be compared with the NPSH available in the system at the eye of the
impeller. The engineer shall consult the pump manufacturer for the NPSH
required values for that pump and compare them with calculated values
for the NPSH available. The NPSH available should be greater than the
NPSH required for a flooded suction pump. The following equation may
be used for calculating the NPSH available:
NPSHA= Pg+ Hs- Pv- Hfs
Where:
Pg = barometric pressure in feet absolute,
Hs = minimum static suction head in feet,
Pv = vapor pressure of liquid in feet absolute,
Hfs = friction loss in suction in feet.
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For lift stations in Round Rock's service area a barometric pressure of
thirty-three and four tenths (33.4) feet may be used and a vapor pressure
of one and four -tenths (1.4) feet may be used. These values are based on
the following assumptions: an altitude of five hundred (500) feet above sea
level, a water temperature of 85°F and a specific gravity of water of 0.996
at 85°F.
6. Suction Piping Design
a. All suction piping shall be flanged ductile iron and have a minimum
diameter of four (4) inches. Each pump shall have a separate suction
pipe.
b. Suction piping shall have a velocity of three (3) to five (5) fps.
c. All suction pipes inside the wet well shall be equipped with a flare type,
down -turned intake. The distance between the bottom of the flare and
the floor of the wet well shall be between D/3 and D/2 where D is the
diameter of the flare inlet.
7. Force Main Design
a. All force mains shall be Ductile Iron, Class 150 with non -corrosive PVC
C-900 lining, an approved HDPE, or PVC C-900, Class 150 with a
minimum diameter of four inches. Force main pipe within the station
shall be flanged. Flexible fittings shall be provided at the exit wall.
b. Force mains shall be sized so that the flow velocity is between three
(3) and six (6) feet per second at ultimate development. During initial
development phases, flow velocities may be as low as two and one
half (2.5) feet per second.
c. The maximum time required to flush the force main shall be calculated
on the basis of average dry weather flow. Flush time shall be
calculated for average dry weather flow using the following equations:
*See Section 1.8.3.H.3.a, "Wet Well Detention Time", for an
explanation of V and q.
d. Odor and corrosion control shall be provided for the force main if the
force main detention time exceeds thirty (30) minutes.
e. The design engineer shall evaluate location and size of all air release
valves for odor or nuisance potential to adjacent property. The use of
air release valves shall be restricted to installations where there are no
possible alternatives.
f. Lift station/force main systems shall be evaluated for their sulfide
generation potential and their ability to achieve scouring velocities
during average dry weather flow periods. If the evaluation indicates
that sulfide concentration of greater than two (2) ppm and solids
deposition are likely, the design shall:
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g.
1) define a workable sulfide control technique that will minimize sulfide
formation in the force main;
2) include "pig" launching stations and recovery points to allow
cleaning of the force main; and
3) protect the gravity main and manholes downstream of the force
main from corrosion. The length of pipe to be protected shall be
determined on a case-by-case basis.
The force main shall discharge into its own distinct manhole. (i.e.
multiple force mains shall not discharge into a single manhole.)
h. Thrust restraint when required shall be shown on the plan view.
8. Head Loss Curves
a. Data points for the system capacity curve shall be provided in tabular
form and graphed with pump head capacity curve on the same graph.
Two (2) system capacity curves shall be plotted using the Hazen
Williams coefficient values of C = 100 and C= 120.
b. Pump output in gpm at maximum and minimum head shall be clearly
shown on the system curve for each pump and combination of pumps.
c. For stations with two (2) or more pumps operating in parallel, multiple
and single operation points shall be plotted on the system curve.
d. Pumps with the highest efficiencies at all operating points shall be
used.
e. If pumps are equipped with smaller impellers during start up to handle
lower than design flows, impellers sized to handle the design flow shall
also be provided.
9. Buoyancy Calculations
The lift station design shall include a complete analysis of buoyant forces
on the entire lift station structure.
10. Water Hammer
a. Calculations for water hammer showing maximum pressures, which
would occur upon total power failure while pumping, shall be provided
using the following equations:
p = (a)(V) / (2.31)(g) + operating pressure of pipe (psi)
a = 12 _ { (w/g) [(1/k) + (d/Et)] } 0.5
Where:
p = water hammer pressure (psi)
a = pressure wave velocity (ft/s)
w = specific weight of water (62.4 Ib/ft3)
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g = acceleration of gravity (32.2 ft/s2)
k = bulk modulus of water (300,000 psi)
d = inside diameter of pipe (in)
E = Young's modulus of pipe (psi)
t = pipe wall thickness (in)
v = flow velocity in pipe (ft/s)
Surge control measures shall be provided when pressures, including
those due to water hammer, exceed the pressure rating of the pipe.
11. Suction Specific Speed
Suction specific speed of the pumps shall be calculated using the
following formula:
SSS = E(Q)5 / (H)75
Where: SSS = Suction specific speed (rpm)
Q = flow at best efficiency point, gallons per minute (gpm)
H = net positive suction head required at maximum impeller speed,
in feet
E = speed of pump and motor, in revolutions per minute (rpm)
Suction specific speed should be below 9,000 rpm to ensure that the
pump would not cavitate because of internal recirculation.
12. Stiffness Ratio
In order to ensure that the pump shaft does not bend an excessive
amount, the engineer shall calculate the stiffness ratio of the shaft using
the following equation:
Stiffness Ratio = L3/D4
Where:
L = distance from impeller centerline to the centerline of the
inboard bearing, in inches
bearing, in inches
D = diameter of shaft (inches)
The stiffness ratio shall not exceed sixty (60).
13. Energy Calculations
For lift stations with flows exceeding seventy five (75) gpm but less than
one thousand (1,000) gpm, and if the engineer is considering a
submersible type lift station as an option then the engineer shall submit
33
cost comparisons for submersible stations versus wet well/dry well
stations. These cost comparisons should include the initial station costs,
installation costs and power costs for the life of the station.
Energy costs for each type station shall be calculated using the following
equations:
a. Calculate the water horsepower required.
WP = (Q)(h)(8.34 lbs./gal) / 33,000 ft -Ib min/hp
Where:
WP = water horsepower (hp)
Q = flow, gallons per minute (gpm)
h = head, feet (ft)
b. Calculate the brake horsepower required.
BHP = WP / pump efficiency*
Where:
BHP = brake horsepower (hp)
WP = water horsepower (hp)
* Use the most efficient pumps for the application.
c. Calculate the electrical horsepower required
EHP = BHP / motor efficiency
Where:
EHP = electrical horsepower (hp)
BHP = brake horsepower (hp)
*Use the most efficient motors for the application.
d. Calculate the power required in kilowatts.
EKW = (EHP)(0.746 Kw/hp)
e. Calculate daily power consumption in kilowatt-hours.
E = [(EKW1)(t1) + (EKW2)(t2) + (E KW3)(t3)...]
Where:
E = total power consumption, kilowatt hours (kWh) per day
EKWn = power required, kilowatts for pumps 1,2,...,n
to = estimated pump run time in hours per day for
pumps 1, 2, ..., n
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f. Calculate the estimated cost for power consumption over the life of the
station.
C = (E)($0.012/kWh)(T)
Where:
C = cost of power over the life of the station (dollars)
E = power consumption (kilowatt-hour per day - kWh/day)
T = time the station is expected to be in service (days)
g. Stress and thrust calculations for internal station piping and bends
shall be provided for stations with flows over one thousand (1,000)
gpm.
14. Sump Design
The following items apply for lift station dry well sump pumps:
a. Dual submersible sump pumps, each with a minimum capacity of one
thousand (1,000) gallons per hour (gph), shall be provided.
b. The design head of the sump pumps should be the static head from
the sump to one (1) foot above the one hundred (100) year flood level
plus allowances for pipe friction both inside and outside the pump
chamber.
c. Sump piping shall be galvanized steel with a minimum diameter of two
(2) inches.
d. Sump discharge from the dry well shall be installed through the wall of
the wet well at a point not less than twelve (12) inches above the top of
the influent pipe and grouted in place with a water tight seal.
e. The dry well floor shall slope toward the sump pit.
15. Specific Station Requirements
a. All stations will be required to have an equipment -lifting device.
b. Engineering calculations are required showing that temperatures inside
the dry well do not exceed 85°F, while the pumps are operating.
c. Stations with motors greater than one hundred (100) hp shall use a
horizontal pump/motor configuration.
d. Stations with motors that are seventy-five (75) hp and larger shall have
reduced voltage starters of the autotransformer or solid-state soft start
type. Part winding starters and motors are not acceptable. Motors
larger than seventy-five (75) hp shall be designed with a maximum
temperature rise not to exceed 80°C over a 40°C ambient
temperature. Motors larger than three hundred (300) hp may require a
higher temperature rise and may be specifically approved with such.
35
e. Motors seventy-five (75) hp and smaller shall be provided with high
efficiency frames. Maximum temperature rise shall not exceed 90°C
over a 40°C ambient temperature.
f. Stations deeper than thirty (30) feet, measured from the finished floor
to the top of the entrance tube, shall require an electrically powered
personnel lift.
Entrance hatches larger than forty (40) inches in diameter shall be
spring- loaded.
h. Valves higher than six (6) feet above the floor shall have chain
operators.
i. Any potable water supply below the overflow elevation of the wet well
shall be protected by an air gap.
All lift stations must have a back-up power source. Looped service
from two (2) different substations is adequate backup power. If a back-
up electric system is not feasible, a diesel generator may be located on
the lift station site instead. Generator shall be equipped with noise and
air pollution control devices.
k. Flow monitoring will be provided for all lift stations.
16. Wastewater Lift Station Specifications
In addition to the design criteria presented in this document, the City has
the "Wastewater Lift Station General Specifications and Drawings". These
documents delineate minimum City requirements as they relate to the
construction and installation of wastewater lift stations. Copies of these
documents are available and can be obtained from the City.
17. Exceptions
Exceptions to these design criteria must be requested in writing. Written
approval from the City must be obtained before any exceptions will be
allowed.
g.
I. Alternate Wastewater Systems
1. General
Low-pressure wastewater systems are discouraged and will be allowed
only where conventional gravity service is not possible. For the purpose
of these criteria, low-pressure sewer service is defined as private grinder
pump facilities or private septic tank effluent pump facilities that do not
convert to gravity flow at or prior to the property line. There shall be no
more than one grinder pump facility per single family or duplex residential
lot. Each grinder pump shall discharge to a gravity flow system. Grinder
pump facilities for commercial establishments, Public Utility Districts
(PUD) or condominiums will be considered on a case-by-case basis.
36
The distance for each grinder pump from the property line to the gravity main
shall not exceed two hundred (200) feet.
Flows may be calculated using the Lift Stations Design Criteria provided in
Section 1.8.3.H. above disregarding the Infiltration/Inflow flow component.
If the above criteria are applicable and a low-pressure wastewater service is
necessary, The City will be responsible for maintaining the portion within the
right-of-way only.
Design and installation of the property owner's pumping system, as well as all
associated plumbing shall be reviewed, approved and inspected by the City.
The system shall be designed as a complete system including all
connections, pumps, etc. for Tots being served by the system. If the above
criteria are not applicable, refer to Lift Stations Design Criteria, Section
1.8.3.H.
2. Connection to Gravity Main
Each grinder pump facility shall be individually tied into a manhole on an
existing gravity main. If a manhole does not exist, one shall be constructed.
Construction costs and all other associated costs shall be the responsibility
of the property owner.
The connection to the gravity main shall be designed to minimize turbulence
and the release of hydrogen sulfide. The discharge point shall be at or
below the spring line of the gravity main.
3. Clean-out and Valve Assemblies
A clean-out and corrosion resistant eccentric plug valve shall be placed
just inside of the right-of-way where City maintenance begins and private
maintenance ends. This clean-out will allow the property owner's system
to be isolated and the City's portion of the system to be pressurized,
flushed or rodded.
Clean -outs and corrosion resistant eccentric plug valves shall also be
installed at bends of 45° degrees and greater. Refer to applicable City
Standard Detail(s).
4. Separation Requirements
The separation between low-pressure sewer lines and waterlines shall
comply with the TCEQ rules and regulations, City's DACS - Standard
Specifications Manual and all other applicable rules and regulations.
5. Grinder Pump System General Specifications and Drawings
In addition to the design criteria presented in this Manual, the City maintains
the "Grinder Pump System General Specifications and Drawings". [NOTE:
why aren't these in the DACS?] These documents delineate minimum
City requirements as they relate to the construction and installation of
37
grinder pump systems. Copies of these documents are available and can be
obtained from the City.
1.7.4. Reuse Water Systems
Any reuse water distribution system connecting to the City's reuse water distribution
system, whether public or private, shall be designed and constructed in accordance to
the standards and specifications, herein.
If determined by the City that the development is suitable for reuse water then, the
developer shall provide all reuse water lines necessary to properly serve the project,
and insure that existing and/or new reuse water facilities can supply the required
demand. The developer shall install all necessary on-site and off-site mains and shall
extend service to all Tots terminating with a meter stop and meter box. For the orderly
extension of reuse water lines as established in the Reuse Water Master Plan, the
developer shall install reuse water mains to the boundaries of his development of the
abutting land. The developer shall submit a letter certifying and sealed by a Professional
Engineer licensed by the State of Texas that the system has been designed in
accordance with the requirements of this section and conform to the rules, regulations,
and requirements established by the TCEQ Design Criteria in the Texas Administrative
Code, as amended.
A. Size/Capacity Determination
1. General
a. Hazen Williams Friction Coefficient C = 120, higher C coefficient may
be used for new mains only upon approval by the City with sufficient
documentation to show effects of long-term use.
b. Average day demand = two hundred and three (203) gal/person/day
c. Peak day demand = four hundred and six (406) gal/person/day
d. Peak hour demand = eight hundred and ninety-three (893)
gal/person/day
e. Maximum static pressure — one -hundred (100) psi unless otherwise
approved by the City.
f. If the maximum static pressure exceeds eighty (80) psi, a PRV will be
required on the property owner's side of the reuse water meter and
should be shown on the plan view.
g. Minimum operating pressure is forty (40) psi at the highest elevation
meter location using average day demands.
2. Peak Hour Demand Requirements
a. The maximum allowable velocity shall not exceed six and one half
(6.5) feet per second (fps).
38
b. The minimum pressure at any point in the affected pressure zone must
not be less than thirty-five (35) psi.
3. Sizing of Reuse Water Mains
All reuse water mains shall be installed in accordance with the Reuse
Water Master Plan maintained by the City. Computer modeling is
preferred for sizing reuse water mains. However, for reuse water mains
less than sixteen (16) inches in diameter other engineering calculation
methods may be accepted. The largest size, as determined by comparing
the service area's peak hour demand and peak day plus fire flow demand,
shall be used. All reuse water mains shall be sized to provide necessary
service to the tract being developed. The City may require oversizing of
certain mains in accordance with City ordinances.
B. Mains
1. Minimum main size shall be eight (8) inches unless the City approves a
smaller size because of unique circumstances. Provisions for a flush valve
at the end of dead end mains may be required. The minimum size for any
street type, however, will be governed by various factors which include
high density land usage, and the designer's consideration of general
system gridding, future mains, neighboring developments and area
configuration. Looped systems are not required at this time. Main sizes will
be as shown in the Reuse Water System Master Plan or determined on a
case-by-case basis and approved by the City.
2. Three (3) inch, ten (10) inch, fourteen (14) inch, and other non-standard
pipe sizes shall not be allowed in typical construction.
3. Reuse water mains in excess of eight (8) inch diameter shall be profiled in
the construction drawings. All reuse water mains shall be profiled in areas
of possible conflicts.
4. Reuse water mains shall be located where maintenance can be
accomplished with the least interference with traffic, structures, and
utilities.
5. The separation between reuse water, water and wastewater mains must
comply with TCEQ rules or have a variance approved by the TCEQ before
submittal to the City. Reuse water mains shall be installed with a
minimum of eighteen (18) inches clearance from other utility and drainage
lines.
6. The standard assignment for reuse water mains shall be on a case-by-
case basis being a minimum of four (4') feet horizontally and two (2') feet
vertically from the potable water line. Reuse water mains shall be on
public property or within a dictated easement generally toward the high
side of the street according to natural topography unless otherwise
accepted by the City. The latter requirement may be relaxed if it is
demonstrated there is one or more compelling reasons to assign a main
39
on the low side of a street (i.e. numerous crossings are avoidable,
maintenance is facilitated, etc.)
When reuse water mains are located outside of the right-of-way, they shall
be within a recorded utility easement. Main assignments in City streets
must be approved by the City. Mains in county roads must also be
approved by the County Engineer.
7. Piping materials and appurtenances shall conform to the City's DACS -
Standard Specifications Manual.
8. Minimum depth of cover over the uppermost projection of the pipe and all
appurtenances shall comply with City's Standard Details; maximum depth
will be as approved by the City for the specific materials, application and
conditions. Reuse water mains shall be kept at reasonable depths three
and one half foot (3.5) to four foot (4) in diameter and larger, automatic air
release valves will be placed at all high points and at the down-slope side
of all valve locations. Automatic air/vacuum and vacuum release valves
shall be approved on a case-by-case basis.
9. For mains sixteen (16) inches and larger, drain valves may be required at
low points.
10. All reuse water service lines shall have a gate valve on the line at the
connection to the main line and a backflow preventer inside the property
line, but accessible for inspection by the City. All un -metered reuse water
service shall have a City approved flow detection device.
11. The design engineer is responsible for determining when air/vacuum
release valves are required. On reuse water mains sixteen (16) inches in
diameter and larger, automatic air release valves will be placed at all high
points and at the down-slope side of all valve locations. Automatic
air/vacuum and vacuum release valves shall be approved on a case-by-
case basis.
12. All pipe and accessories shall be of new materials only. Reuse water
mains shall be Ductile Iron (AWWA C-110, C-104 ANSI/AWWA C -
153/A21.53 -84, min. pressure Class 150) or PVC (AWWA C-900, ASTM
F477 and D3139, min. pressure Class 150), or HDPE (AWWA C-906,
ASTM F714, NSF 61 and PE 3408 by ASTM 3350) with a minimum 11
dimension ratio (DR). Service piping shall be polyethylene as accepted by
the City. All reuse water piping shall be purple or purple wrapped.
Minimum size of service lines shall be as follows:
Parcel Acreage Minimum Line Size
1/3-1 1"
1-2 1.5"
3-6 2"
40
7-11 4"
12-75 6"
More Than 75 8"
13. Service lines under pavement shall be placed in an encasement pipe.
14. Reuse water mains between residential Tots, crossing blocks, shall be
avoided. Reuse water mains along the rear of residential Tots, through
back yards, shall be prohibited. Utility or easement Tots may be
appropriate in some cases.
15. Constructing reuse water mains within state right-of-way shall be
prohibited unless approval is obtained from the City. Reuse water lines in
easements abutting the state right-of-way are allowed provided
easements are unobstructed and accessible.
16. Reuse water mains in easements will be allowed, if it can be
demonstrated that the easement will be unobstructed and accessible, and
that the reuse water main will be a minimum of fifteen (15) feet from any
structure. Minimum easement width shall be fifteen (15) feet and an
additional two (2) feet of easement width provided for every one (1) foot of
depth of cover greater than seven (7) feet. Minimum easement between
residential Tots shall be thirty (30) feet.
17. Meter boxes and vaults shall be reviewed and approved by the City.
C. Valves
1. All valves shall be resilient wedge gate valves. In lines thirty six (36)
inches and larger, butterfly valves may be used except in areas described
below where resilient wedge gate valves are specifically required.
2. Valves shall be located at the intersection of two (2) or more mains and
shall be spaced so that no more than 1,000 feet of reuse water line in
commercial, industrial, or multi -family residential is without water during a
shutout. Valves shall be located at the intersection of two (2) or more
mains and shall be spaced so that no more than 2,000 feet of reuse water
line in off-site transmission mains, and in residential subdivisions is
without water during a shutout.
3. At dead ends, gate valves shall be located one (1) pipe length, with an
eighteen (18) to twenty (20) foot minimum, from the end point of the main.
In lines larger than sixteen (16) inches, these shall be double disc gate
valves. The Engineer shall provide and show drawings for complete
restraint for all such valves, pipe extensions and end caps.
4. Branch piping, both new and future branches shall be separated from the
main with gate valves. In branches larger than sixteen (16) inches these
shall be resilient wedge valves.
41
5. For mains twelve (12) inches and smaller, valves at street intersections
shall be located at opposite point of curvature (p.c.) of the curb line.
6. All valves from six6 inches to twenty four (24) inches shall be gate valves.
Gate valves shall be located on each side of a tee or cross (i.e. each tee
will require three (3) gate valves and each cross will require four (4) gate
valves to be installed). Variations from these requirements require
approval by the City.
8. The operating nut of any valve shall be between eighteen (18) inches and
thirty (30 inches below finished grade. Extensions of valve nuts shall be
provided as necessary to meet the depth requirement. Extensions shall
not be fixed to operating nut.
9. Valves with valve extensions and those at pressure zone boundaries shall
be equipped with a locking type debris cap.
10. All gate valves and butterfly valves shall be installed in accordance with
the City's Standard Details.
D. Services
1. Reuse water services shall be constructed in accordance with the City's
Standard Details. More than two meters on a single service line will be
considered on a case-by-case basis.
2. Individual meter services will not be taken from transmission lines.
Transmission lines are generally considered to be twenty-four (24) inches
in diameter or larger. Exceptions must be approved by City at the time of
plan submittal. The Professional Engineer shall submit a letter with this
request.
E. Reuse Water Meters for Multi -Family and Commercial Customers
A reuse master meter may be required for building permits issued by the City for
multi -family, manufactured home rental community, commercial property, or any
other multiple -use facility, if recommended by the City. The measurement of the
quantity of water, if any, consumed by the occupants of each individual unit shall be
provided by the following:
1. Sub -meters, owned by the property owner or manager, for each dwelling
unit or rental unit.
2. An alternative method approved by the City.
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