Findings

1
Is the City of Oberlin a source or a sink for
pollutants? Water quality in Plum Creek as a
function of urban land cover Jonathan Cummings,
Tami Reed, and Kate Weinberger Systems Ecology
(ENVS316) 04 Oberlin College, OH
Findings, continued
Findings
Introduction
Method

• Background
• Plum Creek receives most of the water draining
  from the city of Oberlin, and eventually drains
  into the Black River and then Lake Erie
• Oberlins impermeable surface and utilization of
  storm drains may cause increased run-off into
  Plum Creek.
• Storm events are important determinants of
  short-term nutrient delivery in streams because
  they wash debris, sediments and nutrients into
  the water.
• The Plum Creeks pollutant level is of interest
  to the town of Oberlin, the Black River Watershed
  Project and Lake Erie due to potential
  eutrophication effects
• A 1992-1994 EPA study concluded that the Plum
  Creek is an impaired water due to agricultural
  inputs and siltation1
• Previous studies have not evaluated the role of
  storms on water quality in Plum Creek 2.

• Sampling Sites
• We collected water samples from two sites to
  determine Oberlins effect on Plum Creek. The
  first site is located on Pyle Road, upstream of
  all of Oberlins storm drains. The second site is
  located on Route 511, downstream of all of the
  drains.

• Results
• We used our depth readings to plot a hydrograph
  of the storm event

• Conclusions and Take-Home Points
• 1. Turbidity and nutrient concentrations rise
  with increasing water flow rate
• 2. Oberlin tends to dilute Plum Creek during
  storm events. However, it tends to add nutrients
  and turbidity during low flow after storms. This
  is particularly true for turbidity and PO4.
  Although the graph shows that Oberlin adds Cl
  under both conditions, it adds more during low
  flow. Along the same lines while Oberlin always
  dilutes NO2,3 it dilutes more during high flow.
• It is possible that the reason Oberlin dilutes
  Plum Creek during high flow is because other land
  cover/use farther upstream is adding more to the
  creek than Oberlin does. Two possible land uses
  are A) a construction site immediately above the
  upstream site and B) agricultural land cover even
  farther upstream.

References
1 United States Environmental Protection Agency.
1998. Total Maximum Daily Load Listed Water
Information. 2 Fessenden, R.B. and Timberlake,
R.T. 2000. Plum Creek Water Quality Report for
Oberlin College ENVS 316.