Data tables of well locations, perforated intervals, and time series of hydraulic-head observations for the Central Valley Hydrologic Model (CVHM)

This digital dataset defines the well locations, perforated intervals, and time series of hydraulic-head observations used in the calibration 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 U.S. Geological Survey (USGS) numerical modeling code MODFLOW-FMP (Schmid and others, 2006b). 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 USGS and CA-DWR maintain databases of key wells in the Central Valley that are web-accessible (http://waterdata.usgs.gov and http://www.water.ca.gov/waterdatalibrary/, respectively). These data were combined to form a database of available water levels throughout the Central Valley from 1961 to 2003. More than 850,000 water-level altitude measurements from more than 21,400 wells have been compiled by the USGS or CA-DWR and have been entered into their respective databases. However, only a small portion of these wells have both sufficient construction information to determine the well-perforation interval and water-level measurements for the simulation period. For model calibration, water-level altitude data were needed that were (1) distributed spatially (both geographically and vertically) throughout the Central Valley; (2) distributed temporally throughout the simulation period (years 1961-2003); and (3) available during both wet and dry climatic regimes. From the available wells records, a subset of comparison wells was selected on the basis of perforation depths, completeness of record, climatic intervals, and locations throughout the Central Valley. Water-level altitude observations (19,725) for 206 wells were used as calibration targets during parameter estimation. 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).

本数字化数据集明确了用于中央谷地水流系统瞬态水文模型（transient hydrologic model）率定的井位、射孔段与水头（hydraulic head）观测时间序列。中央谷地涵盖美国加利福尼亚州约5万平方千米的区域。美国地质调查局（U.S. Geological Survey，简称USGS）的数值模拟代码MODFLOW-FMP（Schmid等，2006年b版）可对中央谷地复杂的水文系统进行模拟。本模拟即为本文所称的中央谷地水文模型（Central Valley Hydrologic Model，简称CVHM）（Faunt，2009年）。借助MODFLOW-FMP，CVHM可在1961年至2003年间以月为时间步长，模拟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。美国地质调查局（USGS）与加州水资源部（California Department of Water Resources，简称CA-DWR）分别维护着中央谷地重点井的可公开访问数据库，网址分别为http://waterdata.usgs.gov 与 http://www.water.ca.gov/waterdatalibrary/。研究人员将两类数据库的数据整合，构建了1961年至2003年中央谷地全域可用水位数据库。美国地质调查局与加州水资源部已从逾21400口井中整理出超85万条水位高程观测数据，并录入各自的数据库。但其中仅有少量井同时具备足够的结构信息以确定射孔段，且拥有模拟期内的水位观测数据。研究人员基于射孔深度、记录完整性、气候区间以及中央谷地区域分布，从现有井位记录中筛选出一组对比井。在参数率定过程中，选取了206口井的19725条水位高程观测数据作为率定目标。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。CVHM作为美国地质调查局地下水资​​源计划的一部分开发完成（详细信息参见前言A章第iii页）。