Date of Award

12-2003

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Ecology and Environmental Sciences

Advisor

Katherine E. Webster

Second Committee Member

J. Steve Kahl

Third Committee Member

John M. Peckenham

Abstract

Maine lakes and streams serve as significant sources of public water supply, serving 40% of the population. Drought affects surface water resources by reducing water quantity and altering water quality, for example by reducing inputs of materials from the watershed and increasing water residence times. The 2001-2002 drought was the worst in Maine in over thirty years, and it exposed deficiencies in current water resources planning and management. In this study, I evaluated the effects of the 2001-2002 drought on Maine public water systems in order to identify characteristics of systems vulnerable to drought and determine appropriate indicators of drought sensitivity. I also evaluated the future of Maine's water supply industry in a potentially changing climate. In addition to reviewing drought problems reported to the Drinking Water Program and Public Utilities Commission, I surveyed all public surface water systems to identify systems affected by the drought. Historical hydrological and chemical data from a subset of seven public water supply lakes provided a more intensive analysis of the effects of drought on water quantity and quality. Monthly hydrologic conditions antecedent to the drought were assessed to determine the most robust triggers for future use in public water system drought planning and management. Data on lake morphometry, geology, landscape position, land use, and demographics from a second subset of 28 public water supply lakes were assessed to identify the best indicators of drought sensitivity. Manager responses to the drought were documented to establish a record of institutional knowledge for dealing with drought. Forty-five of approximately 400 community groundwater systems and eight of 68 surface water systems were affected by the drought, although most systems experienced below-average water levels. No consistent changes in water quality variables related to water clarity were noted, although comparisons were limited by a lack of consistent source water monitoring data. Environmental factors such as morphometry or geology were not useful predictors of the sensitivity of a particular system to drought. A key finding was that affected systems were withdrawing volumes of water in excess of their safe yield. These stressed systems are located in the populated coastal region and in areas where an increase in water demand is caused by seasonal tourism and development. An essential management conclusion was that drought conditions or low lake levels alone were not enough to drive a system to implement water conservation; increased demand had to occur simultaneously. The best management tool is monthly monitoring of water withdrawals and demand in addition to local climatic parameters. While the scope and direction of future climate change is uncertain, the effects of the 2001-2002 drought indicate that public surface water systems that already operate close to capacity and that experience seasonal increases in demand are most likely to encounter difficulties in a variable and uncertain climate.

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