Plates 1,2, and 3 - Revision of the Accounting Surface Along the Lower Colorado River Scientific Investigations Report 2008-5113, version 1.1 By Stephen M. Wiele, Stanley A. Leake, Sandra J. Owen-Joyce, and Emmet H. McGuire DESCRIPTION OF DATA FILES by Jim Monical INTRODUCTION The accounting-surface method was developed in the 1990s by the U.S. Geological Survey (USGS), in cooperation with Bureau of Reclamation, to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. This method was needed to identify which wells require an entitlement for diversion of water from the Colorado River and need to be included in accounting for consumptive use of Colorado River water as outlined in the Consolidated Decree of the United States Supreme Court in Arizona vs. California. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The study area includes the valley adjacent to the lower Colorado River and parts of some adjacent valleys in Arizona, California, Nevada, and Utah extends from the east end of Lake Mead south to the southerly international boundary with Mexico. Contours for the original accounting surface were hand drawn based on the shape of the aquifer, water-surface elevations in the Colorado River and drainage ditches, and hydrologic judgment. This report documents an update of the original accounting surface based on updated water-surface elevations in the Colorado River and drainage ditches and the use of simple, physically based ground-water flow models to calculate the accounting surface in four areas adjacent to the free-flowing river. Version 1.1 revisions This report documents an update of the original accounting surface based on updated water-surface elevations in the Colorado River and drainage ditches and the use of simple, physically based ground- water flow models to calculate the accounting surface in four areas adjacent to the free-flowing river. The accounting surfaces are displayed on three plates added to USGS Science Investigation Report 2008-5113, version 1.1. This document describes the types and contents of files that form the associated digital database and includes ARC/INFO (Environmental Systems Research Institute, http://www.esri.com) version 9.3 data files in the form of a personal geodatabase as well as shapefiles. Metadata associated with each dataset is also available. ACCOUNTING SURFACE UPDATE (version 1.1) DATABASE FILES Arc/Info Personal Geodatabase format Subject SIR_2008_5113.mdb Cibola_Staff_Gages Staff gage locations in Cibola Valley Colorado_River Lower Colorado River Gila_River Portion of Gila River in study area Havasu_Island Havasu Island in Lake Havasu LCR_AccountingSurface Updated accounting surface LCR_Asurf_Contours Accounting surface contours LCR_AZTR Arizona Township & Range boundaries in study area LCR_AZTRS Arizona Township, Range, & Section boundaries in study area LCR_CATR California Township & Range boundaries in study area LCR_CATRS California Township, Range, & Section boundaries in study area LCR_Cities Cities in study area LCR_FloodPlain Flood plain of the Lower Colorado River LCR_Gages Selected streamgages along the Lower Colorado River LCR_Measpts Selected elevation measuring points along the Lower Colorado River LCR_NEVTR Nevada Township & Range boundaries in study area LCR_NEVTRS Nevada Township, Range, & Section boundaries in study area LCR_Rivermiles Points depicting river miles for the Lower Colorado River LCR_Roads Major roads and highways in the study area LCR_Streams Streams and rivers in the study area LCR_UTAHTR Utah Township & Range boundaries in study area LCR_UTAHTRS Utah Township, Range, & Section boundaries in study area PaloVerde_Staff_Gages Staff gage locations in Palo Verde Valley Parker_Valley_Staff_Gages Staff gage locations in Parker Valley PPV_Drains Groundwater drains in Parker Valley Western_States Boundaries of Western States The geodatabase, SIR_2008_5113.mdb, is in a compressed .zip file, SIR_2008_5113_mdb.zip Arc/Info Shapefile format The shapefiles were exported from the project geodatabase and are named the same as the layers listed above. Each shapefile is compressed in its own .zip file. All compressed shapefiles have been collected in a tar (tape archive format) file, and then compressed using gzip in the file sir5113_shapefiles.tar.gz. Arc/Info Raster format LCR_hill_n.e00 Hillshade for the northern half of the study area LCR_hill_s.e00 Hillshade for the southern half of the study area Because of the file size of the original hillshade, it is been broken down into two separate datasets and then exported, using the Arc/Info EXPORT command, into two export format files. These export files have been compressed into zip files. These two zip files have been collected into a single tar file, sir5113_hillshade.tar.gz. Metadata Metadata for each of the 26 datasets used to create these plates, were exported to FGDC .txt format files which were bundled in a zip format file, LCR_Accounting_Surface_metadata.zip. Each of the individual datasets also contains FGDC complaint metadata.