Project Completion Report, OWRT Project No. A-056-ARIZ / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - June 1975 / Acknowledgement: The work upon which this report is based was supported by funds provided by the State of Arizona and the United States Department of the Interior, Office of Water Research and Technology as authorized under the Water Resources Research Act of 1964. / Specific objectives of the project included (1) examining the effect of pit recharge, using industrial blowdown effluent, on local ground-water levels and quality in the Tucson basin; and (2) evaluating the applicability of two digital models for modelling the hydraulic response of the aquifer to pumping and recharge. Fourteen pit trials ranging from 1 day to 185 days duration were implemented during a two year period. The total volume of effluent recharged was 157 ac-ft. Pit recharge on a limited basis did not appear to offset the general decline in local ground -water levels. However, recharge deteriorated the quality of ground water in shallow (150 ft) wells but not in a deeper (300 ft) well. A finite difference (FD) model and a finite element model (FEM) were used to simulate hydraulic conditions in a 2000. ft by 2000 ft aquifer region near the pit. An attempt was made to calibrate the models using water level data from a two-week aquifer test on a shallow well. Results were depicted using a three-dimensional graphics technique (SYMVU). Better results were obtained with the FD model than with the FEM, primarily because a finer mesh was used to discretize the region with the FD model than with the FEM. Results of the FEM were also biased by the rectangular configuration of the aquifer boundary. The finite element model was used to simulate aquifer response during a pit recharge test. Again, results were limited by the injudicious selection of elements and boundary configurations.

No description available.

<p>This study focuses on the development of a Direct Aqueous Injection Gas Chromatographic method with Flame Ionization Detection (DAI-GC/FID) for the analysis of MTBE and TBA. The analytical method was then applied in a site specific study where MTBE contamination was evident. The method achieved detection limits of 1 ppm for MTBE and 0.1 ppm for TBA. The method showed good precision, accuracy and selectivity. The method was selected primarily for its ability to simultaneously analyze MTBE and TBA. The result of the site specific study showed the persistence of high concentrations of MTBE and TBA at the source of contamination, whilst concentrations at the adjacent primary school dropped to below detection limits as a result of rapid natural attenuation. It was found that an overall decrease in MTBE concentrations was met with an increase in TBA concentrations / which is a direct indication of MTBE degradation. Despite the fact that problematic MTBE concentrations persist at the source of contamination, limited evidence of the persistence of MTBE contamination was identified at the adjacent primary school. As such, MTBE health risks from existing pathways were found to be irrelevant for receptors at the adjacent school.</p>

The impacts of aspen clear-cutting on upland groundwater recharge are presented based on two years (2007-2008) of the five year (2005-2009) HEAD2 NSERC-CRD paired-catchment experiment. Research was conducted at the Utikuma Region Study Area (URSA), 370 km north of Edmonton, Alberta, Canada, in the Boreal Plain ecozone. Results show greater soil water content in the root zone and potential for recharge into the deeper unsaturated zone during the first year of regeneration. Sites with shallow water table levels (<600 cm) increased more than sites under uncut conditions. Sites with deeper water table levels (>600 cm) responded minimally, if at all, to spring-melt and summer storms suggesting that water exchanges with the atmosphere occurred to and from the unsaturated zone only during the first-year regeneration. Upland groundwater gradients to adjacent pond-peatland complexes persisted at least ten times longer under clear-cut than under uncut conditions. Water table trends recovered to uncut conditions by the second year of regeneration. / Ecology

The focus of this study was on recharge mechanisms and recharge estimation within the Table Mountain Group area. The study evaluated recharge processes and recharge estimation methods in the Table Mountain Group aquifer systems.

Doctor of Philosophy(PhD) / In many areas of India, increasing groundwater use has led to depleted aquifers. Rainwater harvesting (RWH), the small scale collection and storage of runoff to augment groundwater stores, is seen as a solution to the deepening groundwater crisis in India. However while the social and economic gains of RWH have been highlighted, there has not yet been a thorough attempt to evaluate the impacts of RWH on larger catchment hydrological balances. The thesis here will endeavour to address this research gap through a case study of the 476 km2 ungauged semi-arid Arvari River catchment in the state of Rajasthan. Over 366 RWH structures have been built in this catchment since 1985 by the community and the local non-government organisation (NGO), Tarun Bharat Sangh (TBS). The local effects of RWH structures and general catchment characteristics were determined through field investigations during the monsoon seasons of 2007 and 2008. The analysis described large variability in both climatic patterns and recharge estimates. Potential recharge estimates from seven RWH storages, of three different sizes and in six landscape positions, were calculated using the water balance method, which were compared with recharge estimates from water level rises in twenty-nine dug wells using the water table fluctuation method. The average daily potential recharge from RWH structures is between 12 – 52 mm/day, while recharge reaching the groundwater was between 3 – 7 mm/day. The large difference between recharge estimates could be explained through soil storage, and a large lateral transmissivity in the aquifer. Approximately 7% of rainfall is recharged by RWH in the catchment, which is similar in both the comparatively wet and dry years of the field analysis. This is because the capacity of an individual structure to induce recharge is related to structure size and capacity, catchment runoff characteristics and underlying geology. Due to the large annual fluctuations in groundwater levels, the field study results suggest that RWH has a large impact on the groundwater supply, and that there is a large lateral flow of groundwater in the area. The results inferred from the field analysis were then applied to a conceptual water balance model to study catchment-scale impacts of RWH. An existing model was not used because of the paucity of data, and the need to incorporate an effective representation of RWH function and impact. The model works on a daily time step and is divided into subbasins. Within the subbasin hydrological response units (HRUs) describe the different land use/soil combinations associated with the Arvari River catchment, including irrigated agriculture. Sustainability indices, related to water from groundwater and rainfall for irrigated agriculture demand, were used to compare scenarios of management simulated in the conceptual model. The analysis shows that as RWH area increases, it reaches a limiting capacity from where developing additional RWH area does not increase the benefit to groundwater stores, but substantially reduces streamflow. This limiting capacity was also seen at the local-scale, where cumulative potential recharge from an individual RWH structure reaches a maximum daily recharge rate. These results could have important implications for RWH development, but require further research. The analysis highlighted the important link between irrigation area and RWH area. If the irrigation area is increased at the optimal level of RWH, where the sustainability indices were greatest, the resilience of the system actually decreased. Nevertheless RWH in a system increased the overall sustainability of the water demand for irrigated agriculture, compared to a system without RWH. Also RWH provided a slight buffer in the groundwater store when drought occurred. While RWH addresses the supply-side issues of groundwater operation, the institutions that form rules for groundwater use must also be considered, because of the link between irrigation area and RWH. The Arvari River Parliament, the community-based group in the case study area, was examined according to Ostrom’s factors for collective action. It was found that the major limitation for the effectiveness of this group was the minimal information available about the aquifer characteristics.

Doctor of Philosophy(PhD) / In many areas of India, increasing groundwater use has led to depleted aquifers. Rainwater harvesting (RWH), the small scale collection and storage of runoff to augment groundwater stores, is seen as a solution to the deepening groundwater crisis in India. However while the social and economic gains of RWH have been highlighted, there has not yet been a thorough attempt to evaluate the impacts of RWH on larger catchment hydrological balances. The thesis here will endeavour to address this research gap through a case study of the 476 km2 ungauged semi-arid Arvari River catchment in the state of Rajasthan. Over 366 RWH structures have been built in this catchment since 1985 by the community and the local non-government organisation (NGO), Tarun Bharat Sangh (TBS). The local effects of RWH structures and general catchment characteristics were determined through field investigations during the monsoon seasons of 2007 and 2008. The analysis described large variability in both climatic patterns and recharge estimates. Potential recharge estimates from seven RWH storages, of three different sizes and in six landscape positions, were calculated using the water balance method, which were compared with recharge estimates from water level rises in twenty-nine dug wells using the water table fluctuation method. The average daily potential recharge from RWH structures is between 12 – 52 mm/day, while recharge reaching the groundwater was between 3 – 7 mm/day. The large difference between recharge estimates could be explained through soil storage, and a large lateral transmissivity in the aquifer. Approximately 7% of rainfall is recharged by RWH in the catchment, which is similar in both the comparatively wet and dry years of the field analysis. This is because the capacity of an individual structure to induce recharge is related to structure size and capacity, catchment runoff characteristics and underlying geology. Due to the large annual fluctuations in groundwater levels, the field study results suggest that RWH has a large impact on the groundwater supply, and that there is a large lateral flow of groundwater in the area. The results inferred from the field analysis were then applied to a conceptual water balance model to study catchment-scale impacts of RWH. An existing model was not used because of the paucity of data, and the need to incorporate an effective representation of RWH function and impact. The model works on a daily time step and is divided into subbasins. Within the subbasin hydrological response units (HRUs) describe the different land use/soil combinations associated with the Arvari River catchment, including irrigated agriculture. Sustainability indices, related to water from groundwater and rainfall for irrigated agriculture demand, were used to compare scenarios of management simulated in the conceptual model. The analysis shows that as RWH area increases, it reaches a limiting capacity from where developing additional RWH area does not increase the benefit to groundwater stores, but substantially reduces streamflow. This limiting capacity was also seen at the local-scale, where cumulative potential recharge from an individual RWH structure reaches a maximum daily recharge rate. These results could have important implications for RWH development, but require further research. The analysis highlighted the important link between irrigation area and RWH area. If the irrigation area is increased at the optimal level of RWH, where the sustainability indices were greatest, the resilience of the system actually decreased. Nevertheless RWH in a system increased the overall sustainability of the water demand for irrigated agriculture, compared to a system without RWH. Also RWH provided a slight buffer in the groundwater store when drought occurred. While RWH addresses the supply-side issues of groundwater operation, the institutions that form rules for groundwater use must also be considered, because of the link between irrigation area and RWH. The Arvari River Parliament, the community-based group in the case study area, was examined according to Ostrom’s factors for collective action. It was found that the major limitation for the effectiveness of this group was the minimal information available about the aquifer characteristics.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1982. / Includes bibliographical references (leaves 159-162).

Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 1988. / Includes bibliographical references (leaves 153-166).

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1988. / Includes bibliographical references (leaves 115-117).