From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona / Some groundwater monitor wells produce water quality samples with anomalously high pH measurements. In some of these wells it is obvious that these water quality samples are affected by the bleed-water from the cement used to seal the annuli. To gain an understanding as to why cement bleed -water occurs and how it can be controlled, literature from both the cement and petroleum industries are reviewed. Cement is a very alkaline material. When too much water is used to prepare the slurry, alkaline bleed -water can drain through or along the cement sheath surrounding the casing. This results in an increase in the pH measurements of groundwater samples. This bleed-water can separate from the cement in-three ways: it can move into the formation during cementing, it can accumulate within the cement forming pockets and channels behind the casing, and it can remain within the interconnected capillaries that exist throughout the cement sheath. The drainage of alkaline bleed -water from the cement can be greatly reduced by controlling the amount of water used in the preparation of the slurry. The amount of water added can be monitored during well construction by measuring the slurry density. By implementing this quality control procedure during well construction along with specifying the correct amount of mix-water for the slurry, the elevated pH levels in groundwater samples should be greatly reduced if not completely eliminated.

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, Arizona / Potential groundwater contaminant sources in the upper Santa Cruz basin include copper mines, irrigated agriculture, and urban wastewater. Risks to human health are posed by groundwater contaminants. Analysis of these risks provides useful information to decision makers for comparing groundwater quality management alternatives. Alternatives include preventing the input of contaminants at their sources, preventing migration of contaminants in groundwater to withdrawal points, removal of contaminants at the points of groundwater withdrawal, relocation of withdrawal points, importation of water, and compensation for those who suffer damages. The framework for risk analysis is composed of hazard identification, hazard estimation, risk estimation, and identification and evaluation of risk response alternatives. Potential contaminants identified range from inorganic ions to complex organic molecules. Hazards have been estimated in terms of fate of potential contaminants in the environment and their toxicity. Risks to groundwater quality and human health in time and space are described with the use of a groundwater contaminant transport model. Because information for the analysis is incomplete, the estimation of risks is not without uncertainties. Major uncertainties remain in data on contaminant concentrations and toxicology of contaminants. The results of the risk estimation, including the uncertainties, may be used to evaluate the groundwater management alternatives.

Complete issue of the Proceedings of the 1985 Meetings of the Arizona Section - American Water Resources Association and the Hydrology Section - Arizona-Nevada Academy of Science - April 27, 1985, Las Vegas, Nevada

Complete issue of the Proceedings of the 1986 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 19, 1986, Glendale Community College, Glendale, Arizona