Estimating Urban-Induced Groundwater Recharge Through Coupled Hydrologic Modeling in Ballona Creek Watershed, Los Angeles, CA
Abstract
The current research focuses on the modeling and prediction of urban-induced groundwater recharge in highly developed, semi-arid regions. The groundwater component of the hydrologic cycle goes through significant changes during urbanization and has historically been understudied. The changes brought on by urbanization not only include physical alterations (increased surface imperviousness, channelized flow, increased sub-surface infrastructure etc.) but also changes to the water cycle due to human interactions (increased use of imported water, variable landscape irrigation, industrial water use, etc.). We undertake our initial analysis in Ballona Creek watershed, which contains highly urbanized and diverse portions of the cities of Santa Monica and Los Angeles, California along with more natural land surfaces in the northern portions of the watershed in the Santa Monica Mountains. The primary focus of this research is the development of a fully distributed and coupled surface-groundwater model of the Ballona Creek watershed. We use the three-dimensional finite-difference surface and groundwater flow model, ParFlow, fully-coupled to a land surface model, CLM, at a 30-meter by 30-meter resolution forced by observed meteorological data from 2000 to 2010. Previous work in Ballona includes a detailed historical water budget analysis from the early 1900s to the present. This extensive in situ data set will be used to estimate model parameters as well as provide upper and lower boundaries for groundwater recharge values across the system. Preliminary results focus on annual and seasonal (wet/dry periods) surface and groundwater fluxes, including the influence of natural spring flow and dry weather runoff in the watershed. Los Angeles and the surrounding metropolitan area rely on some of the most extensive and oldest centralized water redistribution projects in the United States where water is transported hundreds of kilometers to support agricultural and urban activities in the Los Angeles area. Increasingly, local governments and water districts are committed to increased reliance on local water sources within the southern California coastal areas including local groundwater, rainwater capture, conservation measures, and recycled water sources. Our ultimate goal is to use the validated model to evaluate the influence of altered landscapes and future climate in developing sustainable groundwater supplies across the southern California region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.H31D1152R
- Keywords:
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- 1829 HYDROLOGY / Groundwater hydrology;
- 1834 HYDROLOGY / Human impacts;
- 1843 HYDROLOGY / Land/atmosphere interactions;
- 1847 HYDROLOGY / Modeling