Jessica L. Feeser, M. Elise Lauterbur

1
Nutrient concentrations along an
agricultural/urban stream during low flow and
post-storm periods as a function of varying land
use and biological processing
Jessica L. Feeser, M. Elise Lauterbur Jennifer
L. Soong Research Project for Systems Ecology
(ENVS 316), Fall 06 Oberlin College, Oberlin OH
Background
Findings Contd.
Methods
Findings

• The 19 sampling locations were selected to
• provide a comprehensive spatial resolution
• throughout the 5 mile section of the stream. The
• accessibility of the points was also taken into
• consideration. See fig. 1, below, for sampling
• locations.
• We collected water samples from the
• stream on two days during the fall, once 48 hours
  after a storm event, and once during a low flow
  period. We expected nutrient concentrations to be
  near their highest at 48 hours after the storm,
  as suggested by Cummings et al. (2004).

• The regression of NOx against Cl-
• concentrations reveals that NOx concentrations
  are
• being affected by biological processing during
  low
• flow, but not during the post-storm period.
• A similar regression of PO43- against Cl-
• indicated that in-stream processes were not
• having much of an affect on PO43-
  concentrations.

Plum Creek is classified as a grade-1 tributary
of the Black River, which is located in North
East Ohio and drains into Lake Erie. Plum Creeks
headwaters are located in agricultural land east
of the City of Oberlin, and the creek runs
through a golf course, a small forested area
(arboretum), and the City of Oberlin, before
receiving the effluent of the Oberlins waste
water treatment plant (WWTP) to the west of the
city. Eutrophication caused by high levels of
PO43- is a major problem in Lake Erie. In order
to understand how Plum Creeks nutrient
contributions to Lake Erie can be reduced, it is
necessary to determine how different types of
land use affect the input of nutrients into Plum
Creek, and how these nutrients are processed
within the stream. There is little knowledge
about how varying land use within Plum Creeks
watershed affects the nutrient dynamics of the
creek. While there have been previous studies
addressing this issue, we feel that none have
examined an adequate number of sample locations
to obtain a comprehensive understanding of the
creeks dynamics.

• NOx concentrations increase throughout the
  agricultural and golf course portions of the
  stream. This indicates that these areas are
  non-point sources of nitrogen. The peak in
  nitrogen concentration at the boundary between
  the golf course and the arboretum indicates a
  drastic difference in the effects of these two
  forms of land use on the creeks water quality.
• The nutrient concentrations in the arboretum
  are inconclusive. This could be a result of its
  small size or of the citys storm-drainage system
  draining into the stream as it flows through the
  arboretum.
• The highest fluctuation in nutrient
  concentrations occur as the stream flows through
  the city, though nutrient concentrations decrease
  overall.
• The peaks in the city are likely due to
  inputs from Oberlins storm-drainage system. The
  overall decrease in concentration suggests that
  urban runoff dilutes the nutrients.
• All ions reach their maximum concentrations
  at the sampling point immediately past the WWTP.
  The WWTP is a point-source of pollutants.

Future Studies

• Because fertilizers are generally applied in the
• spring, it will be necessary to do a full-year
  study in
• order to fully understand the effects of land use
  on the
• streams water quality.
• Studying the streams flow rate at the time of
• sampling will allow quantification of the net
  change in
• nutrient levels between two points.
• Future studies must identify major polluters of
• PO43- within Plum Creeks watershed before steps
  can
• be taken to minimize Oberlins contributions to
• eutrophication in Lake Erie.

Goals Hypotheses

• Goals
• To quantify water quality at multiple
  points along
• Plum Creek during typical autumn conditions
• To identify point and non-point sources of
• pollution within Plum Creeks watershed
• To determine how biological processing
  within
• the stream affects nutrient concentrations during
  low
• flow and post-storm periods
• Hypotheses
• We hypothesized that concentrations of
  nutrients would increase in the agricultural and
  golf course regions, and decrease throughout the
  arboretum and the city.
• We expected that, due to the constant flow
  of
• water, biological activity would have little
  effect on

References
Cummings, J., T. Reed, K. Weinberger. 2004. The
city of Oberlins effect on the Plum Creek
watershed during a storm event variation in
upstream and downstream water quality during
and after storm water run-off as a function of
urban land cover Report for Oberlin College
ENVS 316. Petersen, J. 2006. Methods for
Analyzing Aquatic Ecosystems