The Brownsville Public Utilities Board in conjunction with the City of Brownsville began a city-wide effort to dredge and restore the cities resaca system beginning in late 2012. Over the years, as a result of erosional processes and urban development, the resacas were subject to extreme levels of sedimentation, reduced water quality, and in some instances, fish kills due to eutrophication of the waterway. The initial phase of the project included the restoration of four resaca sites including Resaca Blvd., Cemetery Resaca, Dean Porter Park, and the Gladys Porter Zoo. In total, over 100,000 cubic yards of dredged material was removed and dewatered from the four sites.
Ambiotec assisted the Brownsville Public Utilities Board with scoping the feasibility of the project, evaluating site conditions, and selecting equipment to effectively dredge and dewater the resacas. Ambiotec then assisted in getting the project reviewed and permitted by the U.S. Army Corps of Engineers and Texas Commission on Environmental Quality and in developing dredging plans. Other tasks included collecting cross-section and bridge and culvert information throughout the sites including at the Gladys Porter Zoo, which presented additional challenges due to many pedestrian bridge crossings within the site, segmented (and narrow) resacas that intertwine between animal exhibits, and the need to keep the zoo fully functional during restoration activities. Within the zoo alone, approximately 2-6-ft of sediment was removed from the resaca increasing water depths from less than 1-ft in some areas to between 2-8-ft depth on average.