Date of Graduation
Master of Science in Environmental Management (MSEM)
Gretchen Coffman, Ph. D.
Human development has altered many rivers around the world. In the past, urban rivers were condemned as flood hazards, and load-reducing treatments were the only treatments applied to protect the surrounding communities against flooding. These treatments aim to collect precipitation from the surrounding surfaces quickly and divert the water using the most direct and spatially conservative means as possible- most often using concrete. These treatments have left rivers in ecologically non-functioning states. The channelization of the Los Angeles River in 1938 is a prime example of load-reducing treatment application. This river is unique because it has many constraints of urbanization and is located in a Mediterranean climate, resulting in water availability complications. Completed river projects in Mediterranean climates are presented and the lessons learned from these treatments are applied to the Los Angeles River. Alternative urban river restoration treatments have been successful at using flow-regime management, to return many ecosystem services to riparian ecosystems. Additional objectives were to compare 1.) costs and 2.) ecosystem service restoration success between eight main on-site and eight off-site alternative treatments applicable to urban rivers. Restoration success was evaluated based on the likelihood of restoring ecosystem services (goods and services that benefit humans) related to water quality and hydrologic regime. Due to physical urbanization constraints, the Los Angeles River will never become completely restored. However, this study found that specific reaches within the watershed can be restored to provide natural hydrologic function, retention, infiltration, filtration of water, and natural habitat for the watershed.
Tracy, Nicole M., "Lessons learned from urban river restoration projects: application of restoration treatments on the Los Angeles River." (2014). Master's Projects. 23.