SEPTEMBER 2013 Arizona Department FACT SHEET of Environmental Quality Janice K. Brewer, Governor • Henry R. Darwin, Director Publication Number: FS 13-11 Ambient Groundwater Quality of the Upper Hassayampa Basin: A 2003-2009 Baseline Study – June 2013 Introduction A baseline groundwater quality study of the Upper Hassayampa basin was con- ducted from 2003 to 2009 by the Arizona Department of Environmental Quality (ADEQ) Ambient Groundwater Monitor- ing Program. ADEQ carried out this task pursuant to Arizona Revised Statutes §49-225 that mandates ongoing moni- toring of waters of the state including its aquifers. This fact sheet is a synopsis of the ADEQ Open File Report 13-03.1 The Upper Hassayampa groundwater basin covers approximately 787 square miles within Maricopa and Yavapai counties and is located about 60 miles Map 1 – Sample sites in the northwest of Phoenix (Map 1). The basin Upper Hassayampa basin is characterized by mid-elevation moun- are color-coded according to their water quality status: No tains and had an estimated population Water Quality Exceedences, 2 of 10,479 in 2000. The largest popula- Secondary MCLs Exceedences, Primary MCL Exceedances, and Primary and Secondary MCL Exceedances. (Map by Jean Ann Rodine) tion center is the Town of Wickenburg. tions range from approximately 7,000 Other communities include Congress feet above mean sea level (amsl) in the and Groom Creek. Low-intensity livestock Bradshaw Mountains to 1,900 feet amsl grazing is the predominant land use and along the Hassayampa River about five most ranches have limited acreages of ir- miles south of Wickenburg. The basin is rigated pasture to raise additional animal comprised of federal land managed by feed. There are no surface water diver- the U.S. Forest Service (25 percent) and sions or impoundments besides small Bureau of Land Management (BLM) (21 stock ponds within the basin.2 Ground- percent), State Trust lands (38 percent) water is the only source for public water and private land (16 percent).2 supply, domestic, irrigation and industrial purposes. Public water supply uses the Hydrology 2 most groundwater in the basin. The basin is drained by the Hassayampa The basin is bounded on the north by the River which flows from north to south. Weaver Mountains, on the northwest by The river is intermittent over much of its the Date Creek Mountains, on the south course but has perennial flow in its upper reaches in the Bradshaw Mountains and Figure 1 – The storage tank of the “ML Windmill” also by the Vulture Mountains, and on the serves as a sign post along the rugged Wagoner Road. east by the Bradshaw Mountains. Eleva- where bedrock brings groundwater to OUR MISSION To protect and enhance public health and the environment in Arizona. OUR VISION To lead Arizona and the nation in protecting the environment and improving the quality of life for the people of our FACT SHEET state. Arizona Department of Environmental Quality the surface a few miles south of Wicken- Methods of Investigation enforceable standards are based on a burg. Some of its tributaries, – including daily lifetime (70 years) consumption of To characterize regional groundwater 3 Antelope Creek, Ash Creek, Minnehaha PRINCIPLEStwo liters. AND VALUES Primary MCLs were exceeded quality, samples were collected from 34 Creek, and Weaver Creek – have limited We atadvocate nine for Arizona of the’s envi 34ronment. sites (27 percent). 2 sites (27 wells and seven springs). Of the We adhere to the highest standards of stretches of perennial flow. technicalConstituents professionalism. exceeding Primary MCLs 27 wells, 20 had submersible pumps, six We includecommit to the highestarsenic standards (one site), gross alpha Groundwater is found primarily in the of ethical behavior. were windmills, and one was a monitor- We (fiveare committed sites), to openness, and honesty nitrate (four sites). basin-fill sediments found in the south- ing well. and transparency. We foster relationships built on respect, east portion of the basin. The aquifer courtesyPublic and service. drinking water systems are Samples for inorganic constituents and We value creativity, innovation consists of gravel, sand, silt and clay and andencouraged performance. by the SDWA to meet is capable of yielding several hundred isotopes (oxygen and deuterium) were Weunenforceable, turn challenges into opportunities. aesthetics-based water collected from each site while radon We value our employees gallons per minute. Smaller alluvial de- andquality work as a team. guidelines, called Secondary posits are found along the Hassayampa (17 sites) and radionuclide (12 sites) MCLs, when supplying water to their River in the northern part of the basin. samples were collected at selected sites. customers. Water exceeding Second- Groundwater is also found in limited Sampling protocol followed the ADEQ ary MCLs may be unpleasant to drink amounts in the consolidated crystalline Quality Assurance Project Plan (see and/or create unwanted cosmetic or and sedimentary rocks that constitute www.azdeq.gov/function/programs/lab/). laundry effects but is not considered most of the basin.2 The effects of sampling equipment and a health concern.3 Secondary MCLs procedures were not significant based were exceeded at 13 of the 34 sites Groundwater movement mirrors surface on quality assurance/quality control (38 percent). Constituents exceeding flow, going from north to south. Depth evaluations. Secondary MCLs include chloride (one to groundwater varies across the basin, Water Quality Sampling Results site), fluoride (four sites), iron (two sites), ranging from just a few feet below land manganese (four sites), sulfate (one surface along some stretches of the Has- Groundwater sample results were site), and TDS (eight sites). sayampa River to more than 1,000 feet compared with the Safe Drinking Water below land surface in the center of the Radon is a naturally occurring, inter- Act (SDWA) health and aesthetics-based basin. Natural recharge for the basin is mediate breakdown product from the water quality standards. estimated to be 8,000 acre-feet per year radioactive decay of uranium-238 to Public drinking water systems must while groundwater use is estimated to lead-206. Of the 17 sites sampled for 2 meet health-based, water quality be 3,900 acre-feet per year. radon, none exceeded the proposed standards, called Primary Maximum 4,000 picocuries per liter (pCi/L) stan- Contaminant Levels (MCLs), when sup- dard that would apply if Arizona estab- plying water to their customers. These lishes a multimedia program to address the health risks from radon in indoor air.3 Eight sites (47 percent) exceeded the proposed 300 pCi/L standard that would apply if Arizona does not develop a multimedia program.3 Groundwater Composition Groundwater composition varied throughout the basin in the following ways: • Groundwater chemistry in the basin is most commonly calcium-bicarbonate or mixed-bicarbonate. • Levels of pH measured in the field were slightly alkaline (above seven standard units) except for five sample sites that were slightly acidic (below seven standard units). • Total dissolved solids (TDS) concentra- tions were considered fresh (below Figure 2 – Intermittent flow in the Hassayampa River Figure 3 – An unused aqueduct, the Leppe Wash 999 mg/L) at 32 sites and slightly sa- at the Wagoner Road Bridge. The stream is perennial flume, is located on the historic TK Bar Ranch along at higher and lower elevations in the basin. the Hassayampa River near Kirkland, Arizona. line (1,000 – 3,000 mg/L) at two sites. OUR MISSION To protect and enhance public health and the environment in Arizona. OUR VISION To lead Arizona and the nation in protecting the environment and improving the quality of life for the people of our FACT SHEET state. Arizona Department of Environmental Quality • Hardness concentrations were moder- probably result from human activities commonly impacted the acceptability ately hard (75 - 150 mg/L) at two sites, (four sites > 10 mg/L).4 of water for drinking purposes were hard (151 - 300 mg/L) at 22 sites, very gross alpha and nitrate. • Most trace elements such as alumi- PRINCIPLES AND VALUES hard (301 – 600 mg/L) at eight sites, We advocate for Arizona’s environment. num, antimony, arsenic, beryllium, Gross alpha exceeded health-based, and extremely hard (above 600 mg/L) We adhere to the highest standards of boron, cadmium, chromium, iron, technicalwater professionalism. quality standards in radionuclide at two sites. We commit to the highest standards lead, manganese, mercury, nickel, of ethsamplesical behavior. collected from five sites. Radio- We are committed to openness, honesty • Nitrate (as nitrogen) concentrations at selenium, silver, and thallium were andnuclide transparency. samples were collected how- most sites may have been influenced rarely detected. Only barium, fluo- We foster relationships built on respect, courtesyever, and atservice. only 12 of the 34 sites, so gross by human activities and were divided ride, and zinc were detected at more We value creativity, innovation andalpha performance. had a 42 percent water quality into natural background (eight sites than one-third of the sites. Westandard turn challenges into exceedance opportunities. rate. This finding is at <0.2 mg/L) may or may not indicate We value our employees andnot work asunexpected a team. as large portions of the human influence (20 sites at 0.2 – 3.0 Oxygen and deuterium isotope values at most sites appear to be a product of basin consist of granitic geology and a mg/L) ), may result from human activi- few sites were in the vicinity of historic ties (two sites at 3.0 – 10 mg/L), and the elevation at which the sample sites were located. The five samples that mining activity, both of which are as- sociated with elevated radionuclide Recharge Group experienced little evaporation were 6 characterized as depleted and were concentrations in groundwater. Based collected from sites located high in the on these results, future basin studies Bradshaw Mountains.