The Ground Water Recharge and Pollution Potential of Dry Wells in Pima County, Arizona


  • L.G. Wilson,

    1. L. G. Wilson is a hydrologist in the Department of Hydrology and Water Resources, the University of Arizona (College of Engineering and Mines, Building 11, Tucson, AZ 85721). His educational background is as follows: B.S., agriculture, 1951, University of British Columbia; M.S. irrigation science, 1957, University of California at Davis; Ph.D. soil science, 1962, University of California at Davis. He came to the University of Arizona in 1982. Research interests include artificial ground water recharge and vadose zone monitoring.
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  • M.D. Osborn,

    1. M.D. Osborn is a hydrogeologist with Hargis and Associates (3385 N. Campbell Ave., Tucson, AZ 85719). He received his B.S. in biology in 1973 from the University of South Colorado and his M.S. in hydrology from the University of Arizona, 1987. From 1986–1989 he was a project manager with the Water Resources Research Center, the University of Arizona.
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  • K.L. Olson,

    1. Kevin L. Olson is a hydrogeologist with CH2M Hill's Milwaukee, Wisconsin, office. He received his M.S. in geology in 1983 from the University of Wisconsin and his M.S. in hydrology from the University of Arizona in 1987.
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  • S.M. Maida,

    1. Susan Maida is a hydrogeologist with HydroGeo-Chem (1430 N. Sixth Ave., Tucson, AZ 85705). She received her B.S. in earth sciences from the University of California at Santa Cruz in 1981 and her M.S. in hydrology from the University of Arizona in 1989. Her current work focuses on 36Cl in fractured tuff and tracer studies.
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  • L.T. Katz

    1. Leslie T. Katz is a hydrogeologist with Errol L. Montgomery and Associates (1075 East Fort Lowell Rd., Tucson, AZ 85719). Katz received her B.S. in geology from the University of Arizona in 1983 and her M.S. in hydrology from the same institution in 1987. She is currently involved in hydrogeological projects ranging from locating ground water supplies for a copper mine in Chile to investigating soil and ground water contamination by volatile organic compounds in the Phoenix area.
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This paper summarizes a study to estimate the potential for dry-well drainage of urban runoff to recharge and pollute ground water in Tucson, Arizona. We selected three candidate dry wells for study. At each site we collected samples of runoff, dry-well sediment, vadose-zone sediment, perched ground water, and ground water. Water content data from vadose-zone samples suggest that dry-well drainage has created a transmission zone for water movement at each site. Volatile organic compounds, while undetected in runoff samples, were present in dry-well sediment, perched ground water at one site, and ground water at two sites. The concentrations of volatile organics (toluene and ethylbenzene) in the water samples were less than the corresponding EPA human health criteria. Pesticides were detected only in runoff and dry-well sediment. Lead and chromium occurred in runoff samples at concentrations above drinking water standards. Nickel, chromium, and zinc concentrations were elevated in vadose-zone samples at the commercial site. Of the metals, only manganese, detected at the residential site, exceeded Secondary Drinking Water Standards in ground water. It is concluded that the three dry wells examined during this study are currently not a major source of ground water pollution.