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Securing Arizona's Water Future

Water Supply of the Upper Colorado River Planning Area - Groundwater

Water supplies in the Upper Colorado River Planning Area include Colorado River water, other surface water, groundwater, and effluent.  Colorado River water is the primary water supply in the Lake Havasu and Lake Mohave basins.  It is also used to meet environmental water demands for the Havasu National Wildlife Refuge in the Sacramento Valley Basin.  Elsewhere, groundwater is the primary water supply.  A discussion of Colorado River water entitlements and accounting can be found here.  However, for the purpose of the Atlas, the subsequent individual basin and water supply and demand discussions report the use of Colorado River water as either groundwater, if it is pumped from a well within the hydraulically connected aquifer, or as surface water when it is directly diverted from the river.

Figure 4.0-14 Water Supplies in the Upper Colorado River Planning Area Water Supply Pie

Groundwater

Groundwater is a major water supply in the planning area, meeting 59% of the water demand during the period 2001-2005. (Some of this water was pumped pursuant to a Colorado River entitlement). The location of registered exempt and non-exempt wells is shown in Figure 4.0-15. Groundwater met 92% of the municipal demand, 83% of the industrial demand and 35% of the agricultural demand during this time period and averaged about 101,000 AFA. Groundwater is found at varying depths in the planning area, generally in the 200 to 600-foot range although water levels of more than 1,000 feet bls are found in the Hualapai Valley, Peach Springs and northern Sacramento Valley basins.  Groundwater is pumped from basin fill in most basins with the exception of the Meadview and Lake Mohave basins. Recent stream alluvium is a potentially important aquifer in the Big Sandy, Bill Williams, Detrital Valley and Lake Mohave basins. Sedimentary rocks are principal aquifers in five north and northeastern basins including the Big Sandy, Detrital Valley, Hualapai Valley, Peach Springs and Meadview basins. In the Bill Williams and Sacramento Valley basins, aquifers in volcanic rock are also utilized. Groundwater is limited due to water quality and quantity problems at the town of Chloride, north of Kingman.  Groundwater is the primary or only water supply in most basins with the exception of the Lake Mohave Basin where large volumes of surface water are diverted for agricultural and industrial use.

Well yields appear to be sufficient for most uses in the planning area. Median well yields from large (>10-inch) diameter wells ranged from approximately 35 gpm in Detrital Valley and Meadview basins to more than 1,000 gpm in Lake Havasu and Lake Mohave basins where most wells are in proximity to the Colorado River.  Yields from large wells in the Hualapai Valley Basin were also relatively high, with a median of 900 gpm. In other basins median well yields range from 100 gpm in the Sacramento Valley Basin to 300 gpm in the Bill Williams Basin. Estimated volumes of groundwater in storage may be relatively limited to meet future demands in some areas especially given low groundwater recharge rates. 

The USGS, in conjunction with the Department, in light of proposed land developments, recently conducted investigations of groundwater conditions in the Detrital Valley, Hualapai Valley and Sacramento Valley basins.  As a result, the Department released revised estimates of the volume of groundwater in storage in the Detrital Valley and Sacramento Valley basins.  Groundwater storage estimates to a depth of 1,200 feet bls in these basins are: 1.4 to 3.7 maf in the Detrital Valley, 5 to 5.3 maf in the Hualapai Valley, and 7 to 8.3 maf in the Sacramento Valley.

The Department’s Groundwater Site Inventory (GWSI) database, the main repository for statewide groundwater well data, is available here.  The GWSI database contains of over 42,000 records of wells and over 210,000 groundwater level records statewide. GWSI contains spatial and geographical data, owner information, well construction and well log data, and historic groundwater data including water level, water quality, well lift and pumpage records. Included are hydrographs for statewide Index Wells and Automated Groundwater Monitoring Sites (Automated Wells), which can be searched and downloaded to access local information for planning, drought mitigation and other purposes. 

Approximately 1,700 wells are designated as Index Wells statewide out of over 43,700 GWSI sites (GWSI sites are primarily wells but include other types of sites such as springs and drains). Typically, Index Wells are visited once each year by the Department’s field staff to obtain a long-term record of groundwater level fluctuations. Approximately 200 of the GWSI sites are designated as Automated Wells. These systems measure water levels 4 times daily and store the data electronically. Automated wells are established to better understand the water supply situation in areas of the state where data are lacking.  These devices are located based on areas of growth, subsidence, type of land use, proximity to river/stream channels, proximity to water contamination sites or areas affected by drought.

Detrital Valley Automated Well

Automated Groundwater Monitoring Site, Detrital Valley Basin.  Hydrographs for statewide index wells and automated groundwater monitoring sites can be searched and downloaded through the Department's GWSI webpage.

Volume 1 of the Atlas shows the location of Index Wells and Automated Wells as of January 2009.  At that time there were a total of 93 Index Wells and nine Automated Wells in the Planning Area.  The Automated Wells are located in the Hualapai Valley, Sacramento Valley, Detrital Valley, Bill Williams and Meadview basins. The most updated maps of Index and Automated wells may be viewed at the Department’s website.

Information on major aquifers, well yields, estimated natural recharge, estimated water in storage, aquifer flow direction, and water level changes are found in groundwater data tables, groundwater conditions maps, hydrographs and well yield maps for each basin in the basin sections.

 

water drop Click here to continue to Section: 4.0.6 Water Supply - Effluent and Contamination Sites  

 

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Bill Williams River Detrital Valley Basin