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Bathymetry of the Quarry Pond

Alan Lee and Neil Fitzharris
Aquatic Ecology class, BIO 390, Biology Department, DePauw University
Spring semester 2010

Introduction
Bathymetry is used to estimate the volume of a lake or pond.  It is important to estimate the volume of a body of water prior to stocking with fish to prevent overcrowding.  Food chain lengths are also estimated based on the volume of a water body.

Methods
We established transects across the Quarry Pond and used a GPS unit to keep track of latitude and longitude.  We first attempted to complete our measurements with a raft, but encountered many difficulties.  The raft had a hole in it, and the sonar flashlight was unreliable for estimating depth.  We drifted so much that we were sometimes outside of the range of error for the GPS unit. We then tried to drag the raft across the pond.  This heavily disturbed the bottom of the pond, leaving a long cloud of black sediment.  We tied a lanyard to a fishing weight and a tape measure to measure water depth.  

Results
We found that the surface area of the Quarry Pond was 68,537 square meters (equivalent to 6.85 hectares).  The volume of the Quarry Pond was 69,887 cubic meters. The maximum depth was 2 meters and the average depth was 0.87 meters.

Discussion
We suggest caution if this study is repeated in the future.  We stirred up a lot of black silt while wading through the pond and the silt stayed suspended in the water column.  Our trampling on aquatic plants and almost trampling on fish nests also had potentially adverse effects on the pond ecosystem.