Executive Summary

This storm water study and report was authorized by the Upper Kirby Redevelopment Authority (Authority) under Work Authorization Number 1, dated March 20, 2003. Under this contract, J.F. Thompson, Inc. (Thompson) has conducted a drainage study that identifies the area's drainage problems and compiled this report of recommended improvements. The project is located in southwest Houston, within the Upper Kirby Tax Increment Reinvestment Zone I (TIRZ), in Harris County, Texas. The TIRZ is roughly bound by Westheimer Road to the north, Bissonnet to the south, Shepherd Drive to the east and Buffalo Speedway to the west.

To model this project effectively, a proprietary version of the EPA's Storm Water Management Model (XP-SWMM) was used. Existing (or in situ) and proposed condition models were developed. The existing conditions model serves to establish a hydraulic baseline for comparison with the proposed conditions for the recommended drainage improvements.

The TIRZ is hydraulically divided into three separate drainage systems along three of the major north-south arterials: Kirby, Grecnbriar, and Shepherd.

Three viable alternatives were identified that help alleviate flooding within the TIRZ:

1. Removal/replacement or additional inlets throughout the project area.
2. Storm sewer trunk improvements along Kirby from Bissonnet to US 59 (utilizing a parallel 11-foot x 7.5-foot reinforced concrete box [RCB]), in conjunction with spot improvements north of US 59.
3. Storm sewer trunk improvements along Kirby and Richmond (utilizing parallel 72-inch reinforced concrete pipes [RCPs]), in conjunction with spot improvements north of US 59.

Thompson recommends that the Authority implement Alternative 3. With an estimated construction cost of $14.9 million. Alternative 3 yields the best overall reduction in storm sewer trunk head losses while keeping the overall cost to a minimum. Alternative 3 will relieve the existing ponding within the roadway sections that occur as a result of the inefficient main trunk storm sewers. For the Kirby Drainage System, this relief is accomplished by utilizing a parallel 72-inch RCP storm sewer along Kirby Drive from Richmond Avenue to Westheimer Road as well as a parallel 72-inch RCP along Richmond Avenue from Buffalo Speedway to Kirby Drive. In addition to the parallel storm sewers, improvements are necessary in several locations to improve the efficiency of the lateral lines contributing to the main trunks, as well as area-wide inlet and inlet lead improvements. For the Greenbriar and Shepherd Drainage Systems, larger conduits ranging in size from 24 to 78 inches in diameter are required. Spot side street improvements were also necessary in order to bring these systems into compliance with the City of Houston's 2-year frequency Design Criteria. Once the preliminary engineering phase commences, different design options should be investigated including the use of additional parallel storm sewers that would aid in minimizing construction cost.

The other alternatives were considered but are not recommended due to their cost or inability to provide sufficient relief. Table 1 - Cost Comparison is included below.

Cost Comparison
Alternative	Cost	Advantages	Disadvantages
1	$1.7M	Cheapest	Provides the least Hydraulic Benefit
2	$15.6M	Meets 2-year Design Criteria; Potential Coordination with the SWMP Kirby Drive Project	Most Expensive
3	$14.9M	Meets 2-year Desing Criteria	Traffic Delays while Parallel Storm Sewers are Constructed along Richmond and Kirby