Crystal Brook Flood Control Project - Austin, Texas

This project is one of the largest drainage improvement projects undertaken by the City of Austin. Over 175 homes located in the Crystal Brook neighborhood are currently threatened by frequent flooding and have building floor elevations below the 100-year storm water surface elevations. The objective of this project is to perform hydrologic and hydraulic analyses to study the existing conditions, to develop proposed improvement alternatives to alleviate the flooding problems and to prepare construction documents for the construction of the selected alternative.  Extensive hydrologic and hydraulic investigations and modeling were performed to identify the drainage conditions for the Walnut Creek adjacent to the neighborhood. The computer models and equations used to simulate the watershed conditions included the U.S. Army Corp of Engineers HEC-1, IFH, HEC-2 and HEC-RAS programs, Soil Conservation Service TR-20 program, FHWA HY-8 program, and U.S.G.S. Regression Equations. The proposed improvements consisted of approximately 16,600 lineal feet (ranges from 18” RCP to 12’ x 7’ concrete box) of storm sewer lines, 7,000 lineal feet (ranges from 6’ wide to 100’ wide bottom) of channel improvements and 5,700 feet of flood barrier system. This project also included over 2,000 lineal feet of creek bank stabilization and restoration.

Greenwood Avenue Channel Improvements - Austin, Texas

The project site is located in Tannehill Branch of Boggy Creek in the Central Austin area. The existing homes in the project area experienced severe channel erosion and frequent flooding problems. Raymond Chan & Associates (RC&A) was retained by the City of Austin to develop improvement alternatives to mitigate the erosion and flooding problems for an approximately 500-foot reach of the meandering creek.  RC&A prepared construction plans to add two 4’ x 4’ box culverts to the existing three 5’ x 4’ culverts and enlarge the existing channel section to improve flood flow conveyance and stabilize creek banks in this narrow corridor. By adding culverts, the project cost was less than entirely replacing the existing drainage structure. The existing channel was also enlarged from an approximately 15-foot to a 25-foot bottom width.

City of Georgetown Watershed Master Plan & Drainage Criteria Manual - Georgetown, Texas

Develop regional watershed master plan and floodplain delineation for eleven (11) watersheds.  Project encompasses the City limits and ETJ and includes field inventory of all stream crossings. Utilizing the BOSS RMS (River Modeling System) model, delineated the floodplain for over 70 stream miles of channel within the study area. Based upon the hydrologic and hydraulic models and resulting floodplain delineation, developed a master plan for watersheds that includes channel modifications, culvert expansions, regional detention ponds, acquisition of property, flood warning systems, and drainage ordinances. Additionally, Raymond Chan & Associates, Inc. staff developed a new Drainage Criteria Manual (DCM) for the City of Georgetown. A review of current City of Georgetown Subdivision Regulations and Construction Standards, as wells as the Austin DCM, was performed during the development of the new DCM. Concurrent with the development of the DCM, the City of Georgetown also began developing a new Unified Development Code (UDC).

City of Smithville Stormwater Master Plan - Smithville, Texas

(Individual experience of Mr. Tom Curran)

The project was designed to demonstrate how small cities can manage their storm water through developing partnerships and implementing cost effective controls to provide safe conveyance of stormwater and enhancing the quality of the stormwater prior to discharge. As the project manager and design engineer, Mr. Curran wrote the grant application to EPA under Section 319 of the Clean Water Program and implemented the project to satisfy grant requirements (included acquisition of digital ortho-photography and one-foot topography for the entire city, as the city of Smithville did not have topographic mapping).   He worked with the Texas A&M Capstone Engineering Program to provide civil engineering students the opportunity to work on a real-world situation and served as an adjunct professor for the class teaching hydraulics, hydrology, and about non-point source pollution.  Mr. Curran designed a best management practice to remedy a severely eroded area and to provide permanent stormwater quality enhancement and implemented a stormwater monitoring program utilizing automated sampling equipment. The BMP demonstrated a high capability of removing NPS pollutants from the receiving water. He also developed a regional master plan, authored the master plan report, and presented it to the City Council for adoption. The city adopted the plan and issued bonds to fund the proposed city-wide drainage improvements.