Storm Water
University of Texas Waller Creek Erosion Improvements, Austin, Texas
The University of Texas at Austin (UT) selected Klotz Associates to prepare a Letter Report, Design Documents, Permitting and Engineer’s Opinion of Probable Cost for Construction to improve the proposed erosion conditions along Waller Creek, near the pedestrian bridge, in the immediate vicinity west of Simkins Hall Dormitory.
This location was exhibiting signs of increasing erosion problems along the east bank, especially south of the pedestrian bridge. The report identified potential utility conflicts, permitting requirements, constructability issues, and the potential of two improvement scenarios.
- Erosion improvement Scenario 1 included construction of a Mechanically Stabilized Earth retaining wall limited to the immediate vicinity of the pedestrian bridge (approximately 20 feet on either side).
- Erosion improvement Scenario 2 included a Mechanically Stabilized Earth retaining wall as well of the entire area that was experiencing significant erosion (approximately 20 feet on the north side and 130 feet in south side).
Design documents were prepared for Scenario 2, and the project was permitted and constructed in 2009. Base flows in the creek were bypassed during construction using 2-24” PVC pipes.
Harris County Flood Control District County-Wide Master Plan and On-Call Services, Houston, TX
HCFCD is preparing new Master Plans for the county’s 22 watersheds to determine flood reduction needs and to provide a guidance document to regulate development. Additionally, we have provided On-Call Drainage Services to the County for over 15 years as they implement targeted projects. The plans are being developed in the GIS environment and will be “living documents,” which can be electronically updated as necessary. Klotz Associates is preparing plans for four watersheds – Buffalo Bayou, Clear Creek, Luce Bayou, and White Oak Bayou, totaling 306 square miles. To accomplish HCFCD project objectives, Klotz Associates is providing highly technical hydrologic and hydraulic analyses for major watersheds.
- Utilized state-of-the-art computer software (HEC-GeoRAS, HEC-GeoHMS, ArcMap, Spatial Analyst, and 3-D Analyst) to prepare all technical analysis in the GIS environment
- Developed sub-basins and catchments (200 acre + / -) using the LiDAR-based DEM and GIS software
- Developed catchment flow paths and defined preliminary future channel alignments and right-of-way requirements in undeveloped areas
- Determined level-of-service for existing channels using the new TSARP HEC-RAS models. Mapped floodplains for each frequency, determined flood-prone areas, and developed strategies for solutions
Liberty-Chambers Navigation District Spillway Improvements
Klotz Associates has been selected by the Chambers Liberty Counties Navigation District to provide professional services for planning, design and construction phase services associated with reconstruction of a 150-foot wide overflow spillway for Lake Anahuac in Chambers County. The low flow spillway passes stormwater from Lake Anahuac (freshwater) to Trinity Bay (saltwater).
Lake Anahuac is a source of freshwater for municipal, industrial and irrigation water users in Chambers and Liberty Counties. The lake supplies water to a canal system with over 100 miles of main canal and over 300 miles of laterals. Located at the upper end of Trinity Bay, flood surges of over 20 feet in height from Hurricane Ike destroyed about 4.5 miles of the earthen embankment and the low flow spillway. The top of dam elevation is approximately 8 feet above mean sea level (msl) and the crest of the low flow spillway is at elevation 4 feet msl.
The District is in the process of reconstructing the earthen embankment and is moving forward with reinstallation of the low flow spillway. The current conceptual design for the spillway includes a reinforced concrete cap supported by rows of sheet pile driven to depths of 40 to 60 feet below sea level. Challenges identified for the project include the spillway foundation materials (reported by the District as “sugar sand”), energy dissipation as water flows over the spillway, toe scour at the upstream and downstream ends of spillway, the saltwater environment, water management during construction, use of the spillway as a roadway to travel along the dam and hardening of the spillway to improve survivability in future hurricane events.
Klotz Associates plans to use the services of Chambers County Land Surveying for surveying services and Terracon Consultants for geotechnical services. The current project schedule calls for six months to complete design and six months for construction.
