NONPOINT SOURCE SUCCESS STORY
Implementing Stormwater Management Practices Reduces
Phosphorus and Sediment Loads to Arcadia Creek
A/ t h H I H Nutrients transported in urban runoff from the Arcadia Creek
VVaterDOay I IprOVeO and Qther upstream tributaries led to the eutrophication of
Lake Allegan. Implementing best management practices (BMPs) to reduce nutrient loading led
to dramatically decreased nutrient loads and runoff from the Arcadia Creek subwatershed. Over
time, with continued support and BMP implementation in the larger Lake Allegan drainage area,
these load reductions are expected to contribute to improved conditions in Lake Allegan.
Problem
Arcadia Creek, a small tributary to the Kalamazoo
River in the city of Kalamazoo, Michigan (assessment
unit 040500030606-04), flows into Lake Allegan, a
1,375-acre impoundment on the Kalamazoo River
(Figure 1). Lake Allegan was added to Michigan's
Clean Water Act (CWA) section 303(d) list of impaired
waterbodies in 1996 because excess algal growth
fueled by high phosphorus loads caused the lake to
fail to support its aquatic life designated use. Arcadia
Creek (drainage area of 17 square miles) is not listed
as impaired for phosphorus; however, an assessment
showed that it ranked 5th out of 75 subwatersheds
for the highest total phosphorus loading per unit area,
and is a significant contributor of phosphorus to Lake
Allegan (drainage area of 1,550 square miles). Arcadia
Creekflows through an urban area and is listed as
impaired for bacteria, mercury, polychlorinated biphe-
nyls and dioxin.
The Michigan Department of Environmental Quality
developed a total maximum daily load (TMDL) for
phosphorus for Lake Allegan/Kalamazoo River in
2001. The TMDL called for a 50 percent reduction of
total phosphorus Stormwater loads within the Lake
Allegan/Kalamazoo River watershed.
Project Highlights
Two watershed management plans were developed
that helped guide efforts to reduce nutrients and
other nonpoint source pollutants. In 2006 stake-
holders developed an EPA-approved, nine-element
subwatershed plan for Portage and Arcadia creeks. In
2011 a plan was developed for the larger Kalamazoo
River watershed above Lake Allegan, which also
encompasses Arcadia Creek.
Michigan
Kalamazoo River
Watershed
Arcadia Creek
Watershed
Figure 1. Arcadia Creek is in the Kalamazoo
River watershed in southern Michigan.
Multiple Stormwater best management prac-
tices have been implemented in the Arcadia Creek
subwatershed since the mid-2000s, especially on the
campus of Western Michigan University. Two Clean
Michigan Initiative grants and a Clean Water Act
(CWA) section 319 grant funded the following BMPs
between 2007 and 2011:
• Three Stormwater detention basins, totaling
141 acres in size
• A 395-foot grassed waterway
• A 6.5-acre infiltration/retention basin
• A 0.8-acre infiltration trench
• 3,115 feet of stream bank stabilization (Figure 2)
• 6 acres of vegetated buffers
• 1.6 acres of reconnected floodplain
• 5,900 native vegetation plugs
Additional Stormwater BMPs were installed in the
subwatershed using other grants and local funds.
-------
Table 1. Pre- and post-stormwater BMP total
phosphorus and total suspended solids annual
loadings and event mean concentrations
Figure 2. Project partners reshaped the streambank and added
rock to stabilize this eroding area of Arcadia Creek along Stadium
Drive on the Western Michigan University campus.
Results
To assess BMP performance, post-BMP wet weather
and dry weather water sampling for total phospho-
rus and total suspended solids was conducted in
2013-2014 and compared to pre-BMP data collected
in 2002-2003.
Post-BMP monitoring results demonstrated substan-
tial improvements in phosphorus and suspended
solids loadings, and stream hydrology:
• Average wet weather event mean concentrations
(EMCs) for total phosphorus declined from 0.414 mil-
ligrams per liter (mg/L) in 2002-2003 to 0.254 mg/L
in 2013-2014 (39 percent decline; Table 1).
• Annual loadings of total phosphorus declined from
2,023 pounds in 2002 to 1,234 pounds in 2013-
2014 (39 percent decline; Table 1).
• Average wet weather EMCs for total suspended
solids declined from 137.7 mg/L in 2002-2003
to 89.6 mg/L in 2013-2014 (35 percent decline;
Table 1).
• Annual loadings of total suspended solids declined
from 403 tons in 2002-2003 to 262 tons in 2013-
2014 (35 percent decline; Table 1).
• Average wet weather flows and peak flows were
substantially reduced after BMPs were installed,
despite larger rain events in 2013 and 2014.
• BMP performance studies of two stormwater
detention BMPs demonstrated 85 percent to
99 percent removals of total phosphorus and total
suspended solids.
• Anecdotal reports indicted reduced flooding
throughout the Arcadia Creek watershed after the
BMPs were installed.
Years
2002-2003
(Pre)
2013-2014
(Post)
Annual Loading
Total
phosphorus
(tons/year)
2,023
1,234
Total suspended
solids (tons/
year)
403
262
Event Mean Concentration
Total
phosphorus
(W5/L)1
414
254
Total
suspended
solids (mg/L)
138
90
1 /jg/L = micrograms per liter
In addition, Western Michigan University reduced
its annual total phosphorus load to Arcadia Creek
by 50 percent, and has committed to infiltrating
100 percent of the stormwater from any redevelop-
ment or new development.
Overall, total phosphorus loadings in Arcadia Creek
declined significantly after BMPs were implemented,
indicating that headway is being made toward water
quality improvements. Phosphorus concentrations in
Lake Allegan have also decreased, although interan-
nual variability is significant. More work remains, and
will need to focus on sources in other areas of the
larger Kalamazoo River watershed upstream of Lake
Allegan.
Partners and Funding
The improvement in water quality in Arcadia Creek
was supported by two Clean Michigan Initiative
implementation grants to The FORUM of Greater
Kalamazoo, as well as a CWA section 319 implemen-
tation grant to Western Michigan University (these
three funding sources totaled $1,737,363, including
$536,958 in matching funds). Post-BMP monitor-
ing was funded by a Clean Michigan Initiative grant
to Western Michigan University totaling $73,554
(including $19,154 in matching funds). Partners
in the implementation grants were Kalamazoo
Christian High School, Western Michigan University,
Wildtype Nursery, Geum Services, WildOnes Natural
Landscapers, Kalamazoo River Watershed Council,
the Gun Lake Tribe, Quantum Construction, and the
city of Kalamazoo. Partners in the post-BMP moni-
toring project were the Portage/Arcadia Watershed
Steering Committee, the Kalamazoo Water
Reclamation Plant, the city of Allegan's Wastewater
Treatment Plant, and Kieser & Associates.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001CCC
November 2015
For additional information contact:
Joe Rathbun
Michigan Department of Environmental Quality
517-284-5517
rathbunj@michigan.gov
------- |