Date of Award

8-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Environmental Engineering and Science

Advisor

Moysey, Stephen

Committee Member

Murdoch , Larry

Committee Member

Miller , Shelie

Abstract

Reliable sources of fresh water are a finite resource across the world. Many countries, including India, face water scarcity due to temporal and spatial variations in precipitation, surface water pollution, and depletion of groundwater resources. In order to combat against water scarcity, the government, non-governmental organizations, researchers, and individuals have attempted to create solutions to the water scarcity problem. One solution, which has become popular throughout India is the construction of water harvestings structures (WHS), small earthen dams built to capture monsoonal runoff on ephemeral streams. Villagers believe these structures have a positive effect on groundwater levels and water availability throughout the year, although the direct effect on the local watershed is poorly understood. To better understand the impact of these structures, this thesis investigates the local geology, the watershed and surface water balance, and the monsoonal response of a WHS reservoir in a small watershed in Madhya Pradesh, India.
Field work for this study was completed from May 2009 through April 2010. The accomplishments from the work are three fold. First an improved understanding of the local geology was obtained using electromagnetic induction surveys. Second, major components of the hydrologic cycle were monitored to calculate the flows for the overall water balance and the surface water balance. Finally, water levels in a WHS reservoir were monitored to allow for the reevaluation of a volume balance model proposed for management of these structures for artificially recharging groundwater. The main goal of the project is to determine the impact of water harvesting for artificial recharge and increasing water availability within the watershed.
Information gathered during the geological surveys was used to develop the water balance for the watershed. From the water balance it was determined that streamflow out of the watershed is approximately 15% of the total yearly rainfall. The net transfer of surface water to the subsurface is approximately 80% of precipitation or as a flux normalized to the watershed area is 0.59m/year. The yearly change in groundwater storage is positive and wells are able to recover after two months of pumping for irrigation, indicating current groundwater practices are sustainable and not over drawing the local aquifer.
After consideration of the volume balance for the WHS, it was found that from two to six times the maximum reservoir volume (6.5x104m3) is lost as groundwater recharge from the structure. If the structure is assumed to infiltrate 1.3x105m3/year, without the presence of the structure the yearly streamflow would increase by 48% if the volume of water infiltrated was assumed to be discharged as streamflow. In addition to decreasing streamflow, the upstream reservoir provides a surface water body which is present for ten months of the year, helping to decrease water scarcity in the early dry season.

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