Geosyntec earns ASCE award for Brawley waste site and river stabilization

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Brawley landfill
Brawley Landfill 2013

Geosyntec earned a 2014 Award of Excellence from the San Diego Section of the American Society of Civil Engineers (ASCE) for the Brawley Solid Waste Site Final Closure and New River Stabilization project in California.

The project team received the distinction at the ASCE’s 2014 Civil Engineering Project Awards Banquet, held in May at SeaWorld in San Diego.

The Imperial County Department of Public Works (ICDPW) in El Centro, California, contracted Geosyntec in 2010 to design innovative and beneficial ecosystem solutions that could protect its Brawley Solid Waste Storage Facility from the 100-year floodplain of the nearby New River. With the facility’s closure, ICDPW officials needed to mitigate stability issues resulting from the river’s encroachment into the landfill and cost-effectively and sustainably isolate waste from the surrounding ecosystem.

Due to the nature of the project and its location along the environmentally impacted river, the facility closure design required the input and approval of multiple regulatory agencies, including the US Army Corps of Engineers (USACE), the US Department of Fish and Game, and the California Department of Fish and Wildlife, among others. The large number of agencies involved required a strategic process of building regulatory consensus on each key project element.

The closure and river stabilization project was completed in 2013. Geosyntec’s design included both a re-evaluation of the flood plain and river training methods. The final designs for riverbank stabilization minimized the New River’s erosional threat to the waste facility’s footprint and further reduced the potential for additional impairment of this already impacted waterway.

By installing bendway weirs — submerged rock dikes that are angled upstream to the river’s flow — Geosyntec’s designs allowed the client to gradually enlarge the riverbank area with natural sediment deposition. This deposition of sediment provides the dual benefit of enlarging an area for vegetation growth and the use of wildlife. It also re-directs the river away from the waste storage area using all-natural processes and materials.

“I was impressed with Geosyntec’s willingness to use new and different techniques to get the job done,” said Michelle Mattson, Senior Project Manager at the USACE’s Carlsbad Field Office and the Brawley Solid Waste Site Regulator Supervisor for the Corps.

In addition, a major design goal of the ICDPW was for the final cover system of the closed waste facility to protect the local ecosystem while remaining free of long-term maintenance needs. To accomplish these goals, Geosyntec designed a three-foot evapotranspirative (ET) final cover system using only natural soil and stone.

The firm performed detailed engineering studies to evaluate various material sources that satisfied specific engineering properties. The final ET design incorporated locally available materials found in the Imperial Valley, which reduced the cost and environmental impacts of the project. The final ET design significantly reduces airborne particulates and local erosion. The project also included design of an active landfill gas system to manage emissions.