Location of diversions from the surface-water network of the Central Valley Hydrologic Model (CVHM)

This digital dataset contains the name and location for the diversions from the surface-water network for the Central Valley Hydrologic Model (CVHM). 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 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 total active modeled area is 20,334 square-miles. The CVHM includes complex surface-water management processes. The hydrology of the present-day Central Valley and the CVHM model are driven by surface-water deliveries and associated groundwater pumpage. The Streamflow Routing Package (SFR1) is linked to MODFLOW-FMP to facilitate the simulated conveyance of surface-water deliveries. If surface-water deliveries do not meet the farm-delivery requirement, the FMP invokes simulated groundwater pumping to meet the demand. The surface-water network represents a subset of the entire stream network in the valley. Even so, it covers about 3,000 kilometers of surface-water and is simulated using 208 stream segments that represent 2244 stream reaches, with 43 inflows and 66 diversion locations providing 64 routed and 41 non-routed deliveries. Most of these inflows are regulated by dams and most of the deliveries are conveyed through an extensive canal network. The routed deliveries are conveyed through the simulated surface-water network, while the non-routed delivery conveyance typically occurs through small canals or diversion ditches and are not directly simulated. Much of the surface-water diversion and delivery information was compiled by the California Department of Water Resources (DWR) for 21 water-balance subregions (WBSs) covering the valley floor (C. Brush, California Department of Water Resources, written commun., February 21, 2007). 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 (see "Foreword", Chapter A, page iii, for details).

本数字化数据集包含中央谷地水文模型（Central Valley Hydrologic Model, CVHM）地表水网络取水口的名称与位置信息。中央谷地覆盖加利福尼亚州约50000平方公里的区域，其复杂的水文系统采用美国地质调查局（United States Geological Survey, USGS）的数值模拟代码MODFLOW-FMP进行模拟（Schmid等人，2006），本模拟方案即为本数据集提及的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，模型有效模拟总面积达20334平方英里。

CVHM涵盖复杂的地表水管理流程，当前中央谷地的水文状况与CVHM模型均由地表水配水量及配套地下水抽采量驱动。河道流量演算包（Streamflow Routing Package, SFR1）与MODFLOW-FMP耦合，以实现地表水配水输送过程的模拟：若地表水配水量无法满足农田用水需求，FMP将启动模拟地下水抽采流程以补足需求。

本数据集的地表水网络为中央谷地完整河网的子集，尽管如此，其覆盖约3000公里的地表水河道，共划分为208个河段单元，对应2244个河道段；包含43个入流点与66个取水口，可提供64个演算配水点与41个非演算配水点。多数入流点由水坝调控，绝大多数配水通过大规模运河网络输送。其中，演算配水通过模拟的地表水网络输送，而非演算配水通常通过小型运河或引水渠输送，且未进行直接模拟。

本数据集大部分地表水取水与配水信息由加利福尼亚州水资源部（California Department of Water Resources, DWR）针对覆盖中央谷地谷底的21个水量平衡子区域（Water-balance Subregions, WBSs）整理汇编（C. Brush，加利福尼亚州水资源部，书面沟通，2007年2月21日）。CVHM是美国地质调查局（USGS）开发的最新中央谷地区域尺度水文模型，作为USGS地下水资源计划的一部分开发完成，详细信息参见"Foreword"，A章节第iii页。