MODFLOW-6 model to update and extend the Los Angeles Coastal Plain Groundwater Model

The Los Angeles Coastal Plain (LACP) covers about 580 square miles and is the largest coastal plain of semiarid southern California. The LACP is heavily developed with mostly residential, commercial, and industrial land uses that rely heavily on groundwater for water supply. In 2010, the LACP was home to about 14 percent of California?s population and is also a major commercial and industrial hub. There has been a heavy reliance on groundwater from the LACP for many years. Managed aquifer recharge from the spreading grounds and barrier wells is now a substantial component of the LACP?s groundwater supply. The U.S. Geological Survey (USGS) conducted a study in cooperation with the Water Replenishment District of Southern California (WRD) assessing the historical and present status of groundwater resources in the LACP and the development of tools to better understand the groundwater system. The cornerstone of these tools is the development and application of the Los Angeles Coastal Plain Groundwater-flow Model (LACPGM-USG) to simulate past groundwater conditions, estimate groundwater-budget components and flow paths, and approximate future groundwater conditions under different scenarios (https://doi.org/10.3133/sir20215088).

洛杉矶沿海平原（Los Angeles Coastal Plain, LACP）占地约580平方英里，是半干旱南加州规模最大的沿海平原。该区域开发程度极高，土地利用以住宅、商业及工业为主，供水高度依赖地下水。2010年，洛杉矶沿海平原承载了加州约14%的人口，同时也是重要的商业与工业枢纽。长期以来，该区域高度依赖本地地下水供给。如今，通过铺展渗滤场与防渗井开展的含水层补给管理，已成为洛杉矶沿海平原地下水供应的重要组成部分。美国地质调查局（U.S. Geological Survey, USGS）与南加州补水区（Water Replenishment District of Southern California, WRD）合作开展了一项研究，旨在评估洛杉矶沿海平原地下水资源的历史与现状，并开发工具以更深入地解析该地下水系统。此类工具的核心是开发并应用洛杉矶沿海平原地下水流模型（Los Angeles Coastal Plain Groundwater-flow Model, LACPGM-USG），以模拟历史地下水状况、估算地下水收支组分与径流路径，并预估不同情景下的未来地下水状况（https://doi.org/10.3133/sir20215088）。