Date of Graduation

Fall 2003

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology and Planning

Committee Chair

Robert Pavlowsky

Subject Categories

Hydrology | Sedimentology | Water Resource Management

Abstract

The Valley Mill Reservoir (VMR) was constructed between 1851 and 1871 and drains an important recharge area of the drinking water watershed for Springfield, Missouri. Presently, management efforts to protect downstream water quality are aimed at using VMR as a non-point pollution and sedimentation basin since its watershed is planned for continued urban development. The morphometry of VMR is typical of most reservoirs with an elongated basin and the deepest point being near the dam. Sedimentation within the reservoir has created a delta formation with upstream wetlands and floodplains acting as part of the delta especially during the past. Little evidence is found to indicate that resuspension and sediment focusing is occurring after initial deposition. Sedimentation rates ranged from 0.4 to 1.6 cm/yr from 1871 to 1954, while from 1954 to 1964 sedimentation rates increased dramatically ranging from 2.0 to 5.5 cm/yr. Then from 1964/69 to 1978, rates decreased to 0.7 to 1.9 cm/yr. From 1978 to 2000, sedimentation rates ranged from 0.3 to 2.1 cm/yr. During 2000, a large storm event left a 2 to 5 cm thick sediment deposit. Post-2000 sedimentation rates stayed high with a range of 2 to 4.5 cm/yr. Core sediments within VMR indicate that land use changes within the watershed have increased P and Zn concentrations in the upper 5 to 65 cm. Lead also increased over background levels but since the late 1970’s began decreasing due to the banning of Pb in the environment. Around 1970, after the construction of major highways and increased urban land uses, P, Pb and Zn became enriched over background levels. Initial enrichment of Cu and Hg began much earlier than 1970.

Copyright

© Susan S. Licher

Open Access

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