Public Works - Design Manual Update

On February 26, 2007 the City Council of North Richland Hills unanimously approved a resolution adopting an updated Public Works Design Manual. This final approval was the culmination of months of work by City staff. During the process, efforts were made to poll other metroplex communities and input was sought from local developers and engineers. The City Council, Planning and Zoning Commission, and other City departments also had the opportunity to make comments. The new design standards not only improve the functionality and structural integrity of public improvements, but also consider aesthetics and minimize environmental impacts. The final result is a document which embodies the City of North Richland Hills' current higher design and construction standards and ensures that all new public infrastructure will have a longer, lower-maintenance life.

The previous version of the Design Manual was enacted on February 13, 1995. In the years following this update, City staff became aware of changes that needed to be made to the manual to reflect current City policies and applicable federal and state guidelines. The changes to the manual fall within five areas of justification:

1. New design criteria (or changes to existing)
   • Increase thickness of concrete on residential streets from 5" to 6"
   • Require horizontal curb cuts for residential driveways on existing streets
   • Increase the amount of lime required in the subgrade
   • Increase minimum street grades from 0.5% to 0.65%
   • Increase minimum lot grades from 1.0% to 1.5%
   • Decrease maximum lot grades from 33% to 25%
   • Increase sewer design criteria from 100 to 120 gpcd for flow calculations
   • Discontinue use of Corrugated Metal Pipe for culverts
   • Provide more options for Curb Ramps
   • Lengthen Detector Check Vault to allow for required fittings
   • Revise Blow-Off Hydrant detail
2. Conform to federal and state laws
   • Remove concrete-line channel requirements (Corps of Engineers)
   • Expand Earthen Channel requirements (Corps of Engineers)
   • Storm Water Pollution Prevention Plan requirements (State of Texas)
3. Establish existing staff policies as formal written guidelines
   • Establish Fire Lane geometry
   • Stipulate maximum length of hydrant lead lines
   • Establish requirements for dead-end water mains
   • Clarify vacuum testing requirements for sanitary sewer manholes
   • Establish 15'x70' sight / visibility triangle requirements at certain classifications of intersections
   • Require 5' wide sidewalks when sidewalk is directly behind the curb
   • Update street lighting standards
   • Prohibit "hand poured and formed" concrete for public roadways
   • Increase cul-de-sac radius from 40' to 48' face-to-face
4. Refine specific sections to include more detail
   • Provide additional guidance on construction plan requirements
   • Clarify minimum spacing for curb cuts
   • Expand explanation of floodplain development requirements
   • Clarify "recognized watercourse" definition
5. Cross-reference existing ordinances related to design
   • Traffic Study criteria is outlined in the Traffic Impact Analysis Ordinance
   • Traffic Control Devices as outlined in the Texas Manual on Uniform Traffic Control Devices
   • Curb cuts on TxDOT right-of-way cross-referenced with current TxDOT Access Management Policy
   • Little Bear Creek Corridor Ordinance
   • Detention Pond Ordinance
   • Expand the description of Elevation Certificate requirements per FEMA's website
   • Broaden tree protection section to comply with the Tree Preservation Ordinance

The new Public Works Design Manual and Public Works Construction Details can be viewed online, or a bound version can be purchased at the Public Works Department for $15.00. An electronic version in PDF can also be obtained on CD-ROM from the Public Works Department for $10.00

NRH Public Works Design Manual