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Hydrology in the Bill Williams Basin

Groundwater Hydrology

The Upper Colorado River Planning Area is characterized by semi-arid to arid alluvial basins with few perennial streams.  Anderson, Freethey and Tucci (1992) divided the alluvial basins in south-central Arizona into categories based on similar hydrologic and geologic characteristics.  These categories are useful in describing general hydrologic characteristics. The Bill Williams Basin is in two of these four categories, West and Highland basins.

West Basins

The West basins include the Detrital Valley, Hualapai Valley, and Meadview basins, most of the Sacramento Valley Basin and part of the Bill Williams Basin. Groundwater inflow and outflow are small and there is almost no stream baseflow.  These basins contain extensive areas of basin fill deposits that comprise the primary groundwater bearing unit (aquifer).

Bill Williams Basin (western portion)

Anderson, Freethey and Tucci (1992) categorized most of the western portion of the Bill Williams Basin as a “West” basin, which generally corresponds to the Alamo Reservoir and Clara Peak sub-basins (see Figure 4.2-6).   The area in the vicinity of the Colorado River is influenced by infiltration of river water. Groundwater in the western part of the basin occurs primarily in recent stream alluvium and basin fill.  The water-bearing ability of these units varies within the basin.  The stream alluvium consists of gravel, sand and silt along the Bill Williams River and its major tributaries.  The main water-bearing unit is the basin fill, which is more than 5,000 feet thick in the Bullard Wash-Date Creek Area southeast of Alamo Lake State Park.  Groundwater flow is toward the Bill Williams drainage.

Groundwater recharge is from streamflow and mountain front precipitation and is estimated at 32,000 AFA for the entire basin.  From 10 to 23 maf of groundwater is estimated in storage. There is little groundwater development in the western portion of the basin and relatively little groundwater level data (see Figure 4.2-6).  Available water level data show stable water levels.  Well yields may exceed 2,000 gpm along the Bill Williams River. Arsenic and fluoride concentrations that exceed drinking water standards have been reported from this portion of the basin as well as elevated levels of cadmium near the mouth of the Bill Williams River. 

Highland Basins

The aquifers of the Highland Basins, which generally encompass the northeastern portions of the Big Sandy and Bill Williams, consist of hydraulically connected basin fill and younger stream alluvium.   These aquifers tend to be discontinuous and limited in extent.  Groundwater inflow is from stream channels, mountain front recharge and adjacent consolidated rock aquifers.  Groundwater outflow is due to evapotranspiration and baseflow to streams (Anderson, Freethey and Tucci, 1992).


Click to view Table 4.2-6

Click to view Table 4.2-6 Groundwater Data for the Bill Williams Basin

Click to view Figure 4.2-6

Click to view Figure 4.2-6 Bill Williams Basin Groundwater Conditions

Click to view Figure 4.2-7

Click to view Figure 4.2-7 Bill Williams Basin Hydrographs Showing Depth to Water in Selected Wells

Click to view Figure 4.2-8

Click to view Figure 4.2-8 Bill Williams

Basin Well Yields

Bill Williams (eastern portion)

Groundwater in the eastern portion of the Bill Williams Basin, generally the Burro Creek, Santa Maria and Skull Valley sub-basins (see Figure 4.2-6), is found in basin fill, in fractured and porous volcanic rocks and in younger stream alluvium.  In the Peeples Valley area, the stream alluvium is the main water-bearing unit.  An important water-bearing unit in the Copper Basin area east of Skull Valley is a 1,000-foot thick layer of volcanic rocks with reportedly high well yields in the upper 350 to 400 feet.  Other sources of groundwater are from faults in granite and metamorphic rocks.  Groundwater flow in the Skull Valley Sub-basin is to the southwest in the northern part, and to the northwest south of Kirkland (Figure 4.2-6). 

Groundwater recharge occurs from streamflow and mountain front precipitation. Most groundwater development is in the Skull Valley Sub-basin and at Bagdad although most of the water used at Bagdad for mining operations is transported from the Big Sandy Basin near Wikieup. Well yields in this portion of the basin are generally less than those in the western portion with a number of wells yielding less than 100 gpm (Figure 4.2-8). Median well yield for the entire basin, reported from large diameter (>10 inch) wells, is 280 gpm.  Water level measurements are available primarily for wells located in the Skull Valley Sub-basin. These show relatively shallow water levels in most measured wells (<100 feet bls). Water level change data was not available for most wells in the sub-basin for the period 1990-91 to 2003-04, but was relatively stable for the few wells measured during this period (Figure 4.2-6).  Drinking water standard exceedences in this area are generally due to elevated concentrations of fluoride, arsenic and radionuclides.

Click to view Figure 4.0-5

Figure 4.0-5 Upper Colorado River USGS Watersheds

Surface Water Hydrology

The U.S. Geological Survey (USGS) divides and subdivides the United States into successively smaller hydrologic units based on hydrologic features.  These units are classified into four levels. From largest to smallest these are: regions, subregions, accounting units and cataloging units.  A hydrologic unit code (HUC) consisting of two digits for each level in the system is used to identify any hydrologic area (Seaber et al., 1987). A 6-digit unit code corresponds to accounting units, which are used by the USGS for designing and managing the National Water Data Network.  (See Figure 4.0-5)


Bill Williams Watershed

The Bill Williams watershed has a drainage area of about 5,393 sq. miles (NEMO, 2005).  The watershed drains into Lake Havasu just upstream of Parker Dam near the southern boundary of the planning area.  The greatest elevational range in the planning area, from 8,417 feet at Hualapai Peak to 450 feet north of Parker Dam, is found in the watershed.  The watershed includes the Bill Williams Basin, most of the Big Sandy Basin and the southern portion of the Sacramento Valley Basin.  The watershed is drained by the Bill Williams River and its major tributaries, the Big Sandy and the Santa Maria Rivers and by Burro Creek.  A number of perennial streams exist in the watershed including segments of the Big Sandy River, the Bill Williams River, Burro Creek, Kirkland Creek, Date Creek, the Santa Maria River, and Trout Creek.  Numerous intermittent streams are also present (Figures 4.1-5 and 4.2-5)

Construction of Alamo Dam on the Bill Williams River in 1968 significantly impacted streamflow below the dam. Built as a flood-control structure, the dam is now operated in a manner to benefit downriver wildlife refuges and vegetation along the river.  According to NEMO (2005), 185 miles of perennial streamflow exist in the watershed, mostly restricted to the main stem of the Bill Williams River. Water levels in the Bill Williams River below Alamo Dam are affected by the water levels in Lake Havasu.  Alamo Lake is the largest lake in the watershed with about 13,400 acres of open water surface.  Prior to dam construction the Bill Williams River produced some of the largest floods in Arizona history, with a peak discharge (200,000 ft3/s) comparable to the largest known Colorado River floods (Webb and others, 2007).

Bill Williams River

Bill Williams River near the confluence with the Colorado River, Bill Williams Basin.  Construction of Alamo Dam in 1968 significantly impacted streamflow below the dam.  The dam is now operated in a manner to benefit downriver wildlife refuges and vegetation along the river.

Median annual streamflow in the Bill Williams River below Alamo Dam is about 34,000 acre-feet, but a maximum annual flow of almost 702,000 acre-feet was recorded in 1993.  By comparison, the median annual flow at a gage on the Santa Maria River upstream of the dam is about 10,000 af.  The median annual flow recorded at a gage south of Wikieup on the other major tributary to the Bill Williams River, the Big Sandy River, is about 27,000 af.

Within the watershed, perennial streams originate from spring discharges from crystalline rocks.  Most of the public water supply for the town of Bagdad comes from spring flow that discharges to Francis Creek, a tributary to Burro Creek.  Twelve large springs have been identified in the watershed; the largest is located in the Big Sandy Basin where discharge from an unnamed spring south of Cane Springs measured 1,600 gpm.  The largest spring in the Bill Williams Basin was measured at 228 gpm.  There are no large springs reported in the Sacramento Valley Basin portion of the watershed.  Most springs are located in the vicinity of Valentine, along the Big Sandy River, and near the eastern boundary of the Bill Williams Basin.  All measurements were taken prior to 1980 and some measurements are as old as 1943; therefore, the reported discharges may no longer be representative of current conditions.



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