Implications of Future Urban Ecosystem Management Alternatives for the Water Balance of the Los Angeles Basin

Project Summary

Understanding the connections between urban ecosystems and water use is critical for developing sustainable plans for managing growth in the Los Angeles Basin (LAB). Apparent contradictions exist between the positive benefits of increasing urban vegetation (e.g., the “Million Trees Initiative”) and efforts to reduce the region’s water use. This project reconstructs historical changes in urban ecosystems in the LAB and estimates their effects on the LAB water balance. In turn, researchers apply this knowledge to evaluate the water use implications of future land cover scenarios. The first goal is to combine high spatial resolution remote sensing data with an urban land surface model to estimate how land cover changes have impacted water use and runoff within the LAB over the past several decades. The second goal is to develop alternative future land cover scenarios for the next 20-50 years, including increased tree canopy coverage and a transition of urban landscaping to drought-tolerant vegetation. The alternative scenarios can be quantified to show implications on the LAB water balance, with particular emphasis on evapotranspiration. The integration of remote sensing and land and water use models aims to identify sustainable urban ecosystem management plans for Los Angeles with implications for growing urban areas around the world.

Research Team

Dennis Lettenmaier
Geography, Social Sciences

Ruth Endel 
Geography

Progress and Results

This project so far has examined the impact of historical urban ecosystem changes observed from satellite imagery on the water balance of the LAB over the last several decades. The researchers are examining the effects of past land cover change at fine spatial scales, including construction, vegetation growth and death due to climate conditions, and shifts from irrigated grass to turf.  

Project photo of a lawn sprinkler

Category

Award Year

2017