Drainage Area Improvements, WBS No. M-000282-001-3, SWMP, City of Houston

Scientech, as prime performed the PER for this 502 acre neighborhood with 10 asphalt roads and one major concrete roadway all within the Huntington Bayou Watershed (H100-00-00). The south half of project area was within the 100 year flood plain The objective was is to evaluate the existing drainage system and recommend a viable solution to substantially reduce the flooding problems for the project area. We reviewed the LIDAR, overland flow, and ponding maps and performed limited surveying with some slab elevations of previously reported flooded houses within an area bounded by Ley Rd. to the north, Kirkpatrick Blvd. on the east, Hunting Bayou on the south and Homestead Rd. on the west. The study required a comprehensive hydraulic model for existing and proposed conditions, supplemented by storm and street topography to develop a combined solution to address both overland and ponding issues. In preparing this report, SEI evaluated the effectiveness of three different design alternatives to solve flooding problems in the area, which were: 1). Installation of flap gates at outfalls 2). Ditch improvements throughout the project area, 3) Storm sewer and roadway improvements. After carefully evaluating each alternative, SEI determined that there was no cost effective solution to resolve the drainage problems in the project area. The water surface elevation from Hunting Bayou had a direct effect on the efficiency of Homestead Road, Darien Street and Kirkpatrick Blvd. drainage systems. Given the location of the project area relative to the floodplain and Hunting Bayou, the proposed alternatives proved to be ineffective in lowering the water surface elevation for a 100-year event. While alternative 3, which proposes adding storm sewers along Miley Street, Howton Street, St. Louis Street and Jay Street, lowers the water surface elevation for a 2-year event and improves the roadway conditions for the neighborhood, the alternative was costly and does not improve water surface elevations for a 100-year event. Based on extensive modeling/graphing, we recommended that storm sewers/street reconstruction was not a good engineering practice. This saved City $7.4 million in budgeted CIP that could be used for another viable CIP project.