Storm Water

City of Austin Fort Branch Channel Improvements
The Klotz Associates team surveyed portions of the channel and updated the hydrologic and hydraulic models for the watershed.  The team also conducted several field reconnaissance visits to the channel and photo documented it. Additionally, we performed a GIS evaluation of drainage area development conditions and extended the current hydraulic model upstream past US 290 to an approximately 64-acre drainage area.  More than 260 structures were surveyed to update City database information for the Fort Branch Channel.  Klotz Associates utilized updated information, hydrology, hydraulics, and slab data along with some high water marks calibrate the models to historical recent storm event.  The drainage area, parent development, location of houses in the floodplain, and the floodplain boundaries were prepared in our GIS ArcView computer system.  The team prepared several analyses to utilize available construction plans and reduce the structural flooding of homes and businesses.  Klotz Associates then prepared six alternative analyses and cost estimates to provide the best reduction in structural flooding for the least cost.  Options included structural improvements to the channel, culvert or bridge replacements, natural channel sections, and combinations of these options.  Klotz Associates also prepared a hydraulic analysis of storm sewers along a portion of Westminster Drive to evaluate system capacities and to make recommendations to provide more storm sewer capacity in this area.  Recommendations were submitted to the City of Austin in a report which documented the analyses, alternatives, and recommendations. 

City of San Antonio River Loop Water Quality

Klotz Associates is under contract with the City of San Antonio to prepare a water quality model and sedimentation study for the River Loop on San Antonio River in San Antonio, Texas.  The project will identify water quality improvements needed and target Best Management Practices and remedial measures to improve water quality.

City of Houston Storm Drainage Plan
The scope of this project required development of a comprehensive drainage plan for the City of Houston. To accomplish this, Klotz Associates re-evaluated existing drainage design criteria and all storm sewer systems with the city. The firm developed information in a format compatible with an Arc / Info Geographic Information System (GIS) for all watersheds in the area. Klotz Associates provided digital drawings of all watersheds and input details of available storm sewer systems into the GIS. The firm also developed updated drainage area information and development conditions within each watershed.

Klotz Associates used a mail survey to city residents to determine flood-prone areas. The firm obtained repetitive flood loss data from the city and from the Federal Emergency Management Agency (FEMA). All data was merged into the GIS. Subsequently, each drainage system was evaluated within the GIS environment and a Capital Improvement Plan (CIP) was developed for each watershed. The City used this system to evaluate individual systems quickly and effectively.

Brazoria County Master Drainage Plan
Klotz Associates conducted a countywide drainage study, then provided recommended improvements to meet anticipated future growth needs. The project scope included working with seven drainage districts and the county, assembling data, surveying on a selective basis, establishing a uniform datum, defining drainage areas, defining land use, completing a criteria manual, performing hydrologic and hydraulic modeling, analyzing capacities, performing an alternatives analysis, developing recommendations, and coordinating with the Texas Water Development Board and County staff during plan development.

Harris County Flood Control District (HCFCD) Tropical Storm Allison Recovery Project (TSARP)
After Tropical Storm Allison, HCFCD and the Federal Emergency Management Agency (FEMA) remapped Harris County floodplains with all new hydrologic and hydraulic studies using state-of-the-practice computer software in the Geographic Information System (GIS) environment.  These models are based on the new Harris County LIDAR-based DEM acquired in 2001.  Klotz Associates provided the hydrologic analysis of 872 square miles (approximately 1/3 of the county), covering four watersheds – Cypress Creek, Spring Creek, White Oak Bayou, and Willow Creek.

For this project, Klotz Associates developed hydrographs using the Clark unit hydrograph and modified Puhls routing technique; used HEC-HMS, HEC-RAS, HEC-GeoHMS, HEC-GeoRAS, and ESRI software (ArcMap, Spatial Analyst, and 3-D Analyst) to develop the hydrologic parameters and establish peak flow rates; coordinated closely with the program managers for FEMA and HCFCD to monitor progress and technical issues; worked with the hydraulic consultant on our watersheds to jointly develop compatible HEC-HMS and HEC-RAS models and to extract hydrologic parameters from the HEC-RAS models; calibrated the HEC-HMS models to existing U.S.  Geological Survey stream flow data; and developed HEC-RAS models to evaluate major overflows out of two of the watersheds.

This project demonstrated and reinforced Klotz Associates’ ability to prepare thorough, high-quality, highly technical hydrologic analyses for large watersheds to FEMA standards and to deliver on schedule.  The project also required coordination with two program managers and multiple firms on the team.  Our storm water professionals identified unusual hydrologic conditions and initiated investigations and analyses in coordination with the client.

City of Pflugerville, Wilbarger Creek, Public / Private Regional Detention Pond, Pflugerville, Texas

Klotz Associates, Inc. provided professional engineering services for the design, bid and construction of a regional detention pond located in the City of Pflugerville.   Improvements included 1.2 mile channel realignment, one mile of roadway improvements, 4,500 linear feet of water line, 3,500 linear feet of wastewater lines, three roadway bridge crossings, one pedestrian bridge crossing, and a 30-acre pond.