Spring 1961 hydraulic head in the lower pumped zone of California's Central Valley (from Williamson and others, 1989)

This digital dataset defines the spring 1961 hydraulic head in the lower pumped zone of California's Central Valley. It was used to initiate the water-level altitudes for the lower zones of the transient hydrologic model of the Central Valley flow system. The Central Valley encompasses an approximate 50,000 square-kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the USGS numerical modeling code, MODFLOW-FMP (Schmid and others, 2006). This simulation is referred to here as the Central Valley Hydrologic Model (CVHM) (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The starting heads are based on the water-table and potentiometric surface developed by Williamson and others (1989). Maps of the spring 1961 water-table and hydraulic head in the lower pumped zone are shown in Figure 31 of Williamson and others (1989). The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS). The CVHM was developed as part of the USGS Groundwater Resources Program (Faunt, 2009. See "Foreword", Chapter A, page iii, for details).

本数字化数据集给出了加利福尼亚州中央谷地下部抽水含水层带1961年春季的水力水头。该数据集被用于初始化中央谷地水流系统瞬态水文模型下部带的水位高程。中央谷地覆盖加利福尼亚州约50000平方千米的区域，其复杂的水文系统采用美国地质调查局（U.S. Geological Survey, USGS）的数值模拟代码MODFLOW-FMP（Schmid等，2006）开展模拟。本模拟方案在此被称为中央谷地水文模型（Central Valley Hydrologic Model, CVHM）（Faunt，2009）。借助MODFLOW-FMP，CVHM以月为时间步长，模拟了1961年至2003年间中央谷地的地下水与地表水径流、灌溉农业、地面沉降及其他关键水文过程。初始水头基于Williamson等（1989）构建的地下水位与测压水面。1961年春季下部抽水含水层带的地下水位与水力水头分布图详见Williamson等（1989）的图31。CVHM是美国地质调查局（USGS）迄今发布的最新中央谷地区域尺度水文模型。CVHM是作为美国地质调查局地下水资项目（USGS Groundwater Resources Program）的一部分开发的（Faunt，2009；详细信息参见前言A章节第iii页）。