Agenda No. 14.
CITY COUNCIL MEMORANDUM
| City Council Meeting: | November 12, 2024 |
| Department: | Engineering |
| Subject: | Ordinance 24-S-163 - Conduct a Public Hearing and Consider Amendments to the Public Works Specification Manual. First Reading (B.James/K.Woodlee) |
BACKGROUND
The Unified Development Code (UDC) adopts by reference the City's Specifications Manual. The Specifications Manual is made up of several documents: Public Works Design Guide, Technical Specifications, and Standard Construction Details. The Public Works Design Guide establishes standard principles, criteria, and practices for the design of infrastructure and to protect and preserve the public welfare. The Technical Specifications identify the specific material, execution, and workmanship requirements of public infrastructure construction projects. The Standard Construction Details detail (typically graphically) particular installation elements of construction of the infrastructure. An update of the Design Guide is proposed for a number of reasons and is subject to approval of the City Council in accordance with recent legislative changes to the Texas Local Government Code (LGC).
As stated in the UDC, City Council from time to time, on its own motion, or at the recommendation of City staff amend, change, or modify text in any portion of the UDC to establish and maintain stable and desirable development. It is generally considered good practice to periodically review and update the development regulations due to changing conditions, community goals, and/or State and Federal regulations. The same practice is applicable to design standards adopted by reference in the UDC. This proposed update to the Design Guide includes a cleanup of typographical errors, and inconsistencies, clarification of vague guidance, coordination with other City documents (such as the Master Thoroughfare Plan), and establishment of increased standards for higher quality, more sustainable infrastructure.
Proposed amendments
As stated in the UDC, City Council from time to time, on its own motion, or at the recommendation of City staff amend, change, or modify text in any portion of the UDC to establish and maintain stable and desirable development. It is generally considered good practice to periodically review and update the development regulations due to changing conditions, community goals, and/or State and Federal regulations. The same practice is applicable to design standards adopted by reference in the UDC. This proposed update to the Design Guide includes a cleanup of typographical errors, and inconsistencies, clarification of vague guidance, coordination with other City documents (such as the Master Thoroughfare Plan), and establishment of increased standards for higher quality, more sustainable infrastructure.
Proposed amendments
| Section 1 - General | |
| Section 1.1 | Clarified applicability of design standards to public and private development. |
| Section 2 - Required Submission of Plans | |
| Section 2.1.A) | Updated requirements to reflect digital submittals |
| Section 2.1.B)7) | Added requirement of submittal of engineered plans for retaining walls (relocated from another section) |
| Section 2.1.B)8) | Added requirement of profiles of 12" water mains (previously only required for 16" and greater mains) |
| Section 3 - Street Requirements | |
| Section 3.2 |
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| Section 3.3 |
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| Tables 3.3A, B, C, D, and E | Increased minimum allowable pavement slopes |
| Section 3.3.C)4) | Added limitation of responsibility of roadway dedication and pavement construction based on limitation of current state statute |
| Section 3.3.G)2)a) | Added reference to multiuse path (per Master Thoroughfare Plan) |
| Section 3.3.G)2)c) and 3.3.H)1) | Increased strength of concrete for sidewalks and alleys |
| Section 3.4.D) and Table 3.4.A | Removed reference to geogrid for use as a mitigation technique for soils with high plasticity |
| Section 4 - Storm Drainage Requirements | |
| Section 4 | Removed reference to City-maintained hydrologic and hydraulic models |
| Section 4.1.A) | Clarified design frequency requirements |
| Section 4.1.F) | Added explicit requirement for stormwater discharge to mimic existing or predevelopment flow characteristics so as to not cause adverse impact to downstream property |
| Section 4.4.A) | Added stronger encouragement of provision for post construction water quality BMPs and requirement of consideration for future retrofit of facility to meet future water quality standards |
| Section 4.5.A)1) | Added statement disallowing use of Modified Rational Method for computing stormwater runoff |
| Section 4.5.A)2) | Reduced size of drainage area considered "small" from 200 actes to 50 acres and disallowed use of Rational Method for peak flow calculation if time of concentration is greater than 20 minutes |
| Section 4.5.B)1) | Specified minimum total time of concentration as 5 minutes |
| Section 4.5.B)1)a) | Reduced maximum distance allowable for time of sheet flow in time of concentration calculations from 300 feet to 100 feet |
| Section 4.5.D) | Adopted NOAA Atlas 14 precipitation data for stormwater runoff calculations |
| Section 4.5.G)5)b) | Increased design loading of crossings, culverts, and bridges to HS-25 |
| Section 4.5.E) | Increased freeboard depth requred for channels between 5- and 10-foot depth |
| Section 4.5.H)9)b) | Decreased allowable earthen channel side slopes from 3:1 to 4:1 |
| Section 4.5.H)8)e) | Decreased channel side slope allowance for railing to be required from 2:1 to 3:1 (for channel depths greater than 2 feet) |
| Section 4.5.I)2) | Added requirement of access manholes at all storm sewer junctions |
| Section 4.5.K)1) | Added control of 2-year frequency event to detention facility design |
| Section 4.5.K)9) | Added additional criteria that must be met in order for the consideration of a detention facility with a permanent wet pool |
| Section 4.5.L) | Added requirement for the provision of adequate space for the transition of flow from a drainage outfall to predevelopment conditions prior to leaving property |
| Section 5 - Sanitary Sewer Requirements | |
| Section 5.2.A) | Increased design loading of manholes to HS-25 |
| Section 5.2.G)7) | Added requriement of property line cleanout on all laterals (aligning with previously updated Standard Construction Detail) and removed reference to cleanouts otherwise on public mains |
| Section 5.2.G)8) | Added requirement for sampling port on all non-residential laterals |
| Section 5.2.G)13) | Updated requirement for flowable fill to encapsulate all manholes (aliging with previously updated Standard Construction Detail) |
| Section 5.3.B)4) | Clarified waiting period prior to deflection testing after final backfill and/or pavement construction |
| Section 6 - Water Requirements | |
| Section 6.2.A)1)a) | Corrected distance required between fire hydrant and structure from 500 to 400 feet or as required by the Fire Marshal |
| Section 6.2.A)4) | Added section related to private fire lines limiting length of single connection to public main to 1000 feet and citing references for design criteria and construction specifications |
| Section 6.2.B)2) | Clarified requirement for construction of cross-connecting supply and distribution mains including those on the water master plans and where distance to nearest mains exceeds minimum |
| Seciton 6.2.B)5) | Added prohibition of combined domestic and fire service lines for private facilities |
| Section 6.3.B)1) | Added default requrement for encasement of pipe beneath commercial driveways with provision for exception based on certain considerations |
| Section 6.3.B)2) | Added requirement for encasement of mains crossing thoroughfare roadways |
| Section 6.3.D)2) | Added prohibition of domestic connection to dead end mains and clarified looping requirement |
| Section 6.3.F) | Added storz connection to fire hydrant specification (in alignment with previously updated Standard Construction Detail |
| Section 6.3.J) | Added requirements and standards for replacement of asbestos cement (AC) pipe when new connection is being made or whaere cover is decreased over an existing AC main |
| Section 7 - Inspections and Testing | |
| Sections 7.1.F)1) and 2) | Increased testing frequency for street subgrade and base |
| Section 7.1.G) | Updated infrastructure acceptance submittal requirements to specify only digital formats and specified that asset locations must be surveyed |
| Section 7.1.H) | Brought into alignment with UDC by citing two-year warranty period for public improvements |
GOAL
The goal of Ordinance 24-S-163 is to amend the Public Works Design Guide which is part of the Public Works Specification Manual adopted by reference in the Unified Development Code.
COMMUNITY BENEFIT
The community of Schertz benefits from the facilitation of adequate and efficient provision of well designed, well built public infrastructure.
SUMMARY OF RECOMMENDED ACTION
Staff suggests use of the same evaluation criteria in UDC Section 21.4.7.D. typically used for the evaluation of UDC text amendments.
1. The proposed amendment promotes the health, safety, or general welfare of the City.
In order to promote orderly, efficient, and sustainable development, construction design standards should be reviewed and updated from time to time based on improved industry standards, technologic advances, the City's maintenance capabilities and growing body of experience. Also, to promote health and general welfare, the establishment of clear guidelines and standards for well-designed and constructed infrastructure systems is essential.
2. The proposed amendment is consistent with the goals, objectives, and policies of the UDC and the City.
The City's recently adopted Strategic Plan also highlights the city's goals and objectives. Among these are Sustainable Government, Safe and Livable Community, and Infrastructure Investment. Maintaining an up-to-date Public Works Design Guide with clear, appropriate standards established to promote high quality, sustainable infrastructure is critical to the health, safety, and welfare of the community. These amendments would achieve these goals and policy values in the Strategic Plan.
3. The proposed amendment corrects an error, meets the challenge of changing conditions, or is in response to changes in state law.
The proposed amendments to the Public Works Design Guide specifically address changing conditions of the fast-developing City and better align requirements considering limitations of state statutes.
4. Other factors which are deemed relevant and important in the consideration of the amendment.
The scheduled public hearing provides the opportunity for the Council to determine other relevant factors.
Thj Planning and Zoning Commission met on October 2, 2024, held a public hearing, and made a recommendation of approval to City Council with a 7-0 vote.
1. The proposed amendment promotes the health, safety, or general welfare of the City.
In order to promote orderly, efficient, and sustainable development, construction design standards should be reviewed and updated from time to time based on improved industry standards, technologic advances, the City's maintenance capabilities and growing body of experience. Also, to promote health and general welfare, the establishment of clear guidelines and standards for well-designed and constructed infrastructure systems is essential.
2. The proposed amendment is consistent with the goals, objectives, and policies of the UDC and the City.
The City's recently adopted Strategic Plan also highlights the city's goals and objectives. Among these are Sustainable Government, Safe and Livable Community, and Infrastructure Investment. Maintaining an up-to-date Public Works Design Guide with clear, appropriate standards established to promote high quality, sustainable infrastructure is critical to the health, safety, and welfare of the community. These amendments would achieve these goals and policy values in the Strategic Plan.
3. The proposed amendment corrects an error, meets the challenge of changing conditions, or is in response to changes in state law.
The proposed amendments to the Public Works Design Guide specifically address changing conditions of the fast-developing City and better align requirements considering limitations of state statutes.
4. Other factors which are deemed relevant and important in the consideration of the amendment.
The scheduled public hearing provides the opportunity for the Council to determine other relevant factors.
Thj Planning and Zoning Commission met on October 2, 2024, held a public hearing, and made a recommendation of approval to City Council with a 7-0 vote.
RECOMMENDATION
Approve Ordinance 24-S-163.