Hydrological Studies

Understanding the hydrology of this region is critical in evaluating the potential hydrological impacts of groundwater development. The following provides an overview of existing research and planned analyses.

Previous Hydrological Studies

The U.S. Geological Survey (USGS), Desert Research Institute (DRI), Nevada Bureau of Mines and Geology, Southern Nevada Water Authority (SNWA) and the Las Vegas Valley Water District have been analyzing many of Nevada’s hydrographic basins for decades. Combined, they have collected a tremendous amount of data that serves as the foundation for current water resource investigations. Among the major studies undertaken to characterize groundwater movement and interbasin dynamics were the regional Aquifer System Analysis and the Cooperative Carbonate Terrain Project.

Ongoing Investigations

Since its formation in 1991, SNWA has participated in or funded studies related to the region’s hydrology. Several collaborative efforts with USGS and DRI have yielded important hydrogeological information with significant relevance to the SNWA Clark, Lincoln and White Pine Counties Groundwater Development Project.

Monitoring and Management

Ultimately, the most accurate method of quantifying natural recharge and generating an accurate model of a hydrographic basin or flow system involves careful extraction of groundwater and a comprehensive monitoring program. As part of its proposed work, the SNWA intends to identify and evaluate alternatives for hydrologic management and monitoring. In analyzing the alternatives, it will also consider a variety of measures designed to reduce impacts on phreatophytes and springs.

Hydrologic Effects Analysis

Although data collected during the past six decades has greatly increased the body of knowledge available related to eastern and southern Nevada’s groundwater basin, SNWA is committed to further research that will more specifically define the region’s hydrodynamics. SNWA is conducting an analysis of potential hydrologic effects that includes the compilation of existing data, characterization of hydrogeologic conditions at potential well sites and existing springs, biological characterization of spring-dependent habitats, phreatophyte condition evaluation, regional- and local-scale hydrogeologic characterization and the development of a groundwater flow model.

Below is a brief description of activities currently under way:

Assemble databases
Assemble and maintain map, relational and other databases. These include engineering, hydrologic and environmental components and includes digital map library, hydrologic database, physical/document library and image repository.

Current groundwater conditions
Currently developing maps, graphs and supporting databases to document groundwater levels and chemistry within the study area and characterize hydrogeologic conditions. Depths to groundwater will be further characterized in phreatophyte and irrigated areas. Water rights also will be described.

Characterize current spring hydrologic conditions
Document and analyze current conditions of select springs within the project area, including physical setting, local hydrogeology and spring flow sources and dynamics.

Characterize biological conditions at spring-dependent aquatic, riparian and wetland habitats
Document current conditions of the spring-dependent habitats, including spring pools and brooks, and riparian, wetland and open-water habitats.

Characterize current phreatophyte conditions
This includes distribution of phreatophytes and irrigated vegetation estimated consumptive use and vegetation dynamics.

Characterize hydrogeologic setting
This includes a regional-scale hydrogeologic map, regional-scale hydrogeologic sections, local-scale hydrogeologic maps of spring areas and structural maps.

Develop groundwater flow model
Develop a groundwater flow model to simulate the groundwater effects of the project. The model will be based upon an updated version of the USGS computer program MODFLOW.

Identify and evaluate hydrologic management and monitoring alternatives
Identify and evaluate alternative hydrologic management and monitoring programs for the project.

List of studies

The preliminary list of studies conducted or contracted by SNWA, which may change as the process moves forward, is as follows:

• Annual Report of Well Pumpage, Water Levels, and Recharge at Jean, Ivanpah Valley, Clark County, Nevada: Permit Nos. 17691, 21997, 51133, 51543, 51544, 52732, 52733, 52734, 52735, 53736, and 54983 from 1997 through present (2007)
• Analysis of Potential Water-Related Effects of Southern Nevada Water Authority's Proposed Groundwater Development Project in Three Lakes Valley South, Clark County, Nevada (Asset# 1804)
• Baseline Characterization Report for Clark, Lincoln, and White Pine Counties Groundwater Development Project, 2008.
  • Summary Report
    • Volume1: Geology of White Pine and Lincoln Counties and Adjacent Areas, Nevada and Utah: The Geologic Framework of Regional Groundwater Flow Systems
    • Volume 2: Physical Settings of Selected Streams in Clark, Lincoln, and White Pine Counties Groundwater Development Project
    • Volume 3: Physical Settings of Selected Springs in Clark, Lincoln, and White Pine Counties Groundwater Development Project
    • Volume 4: Water-Level Data Compilation and Evaluation for Clark, Lincoln, and White Pine Counties Groundwater Development Project
• Delamar, Dry Lake, and Cave Valley Stipulation Agreement Hydrologic Monitoring Plan Status and Data Report; Doc No. WRD-ED-0002
• Geologic Data Analysis Report for Monitor Well 180W902M in Cave Valley – October 2007, RDS-ED-0003
• Geologic Data Analysis Report for Monitor Well 181M-1 in Dry Lake Valley – October 2007, RDS-ED-0005
• Geologic Data Analysis Report for Monitor Well 181W909M in Dry Lake Valley – October 2007, RDS-ED-0007
• Geologic Data Analysis Report for Monitor Well 182M-1 in Delamar Valley – October 2007, RDS-ED-0002
• Geologic Data Analysis Report for Monitor Well 182W501M in Cave Valley – October 2007, RDS-ED-0004
• Geologic Data Analysis Report for Monitor Well 182W906M in Delamar Valley – October 2007, RDS-ED-0001
• Geologic Data Analysis Report for Monitor Well 209M-1 in Pahranagat Valley – October 2007, RDS-ED-0006
• Geology of White Pine and Lincoln Counties and Adjacent Areas, Nevada and Utah: The Geologic Framework of Regional Groundwater Flow Systems HAM-ED-0001 (Asset#2432)
• Hydrogeology of Tikaboo Valley and Three Lakes Valleys Clark and Lincoln Counties, Nevada (Asset# 860)
• Las Vegas Valley Water District Artificial Recharge Annual Reports from 1993 through present (2007)
• Spring Valley Stipulation Agreement Hydrologic Monitoring Plan Status and Data Report; Doc No. WRD-ED-0001
• Water Resources Assessment and Hydrogeologic Report for Cave, Dry Lake, and Delamar Valleys, 2007. DDC Exhibit #236
• Water Resources Assessment for Spring Valley, 2006. Spring Valley Exhibit #509