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Eliminate the Sediment and Erosion; Bring Back the Fish |  |
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The Bigalk Creek, a springfed, coldwater tributary of the Upper Iowa River in northeast Iowa, has a unique limestone bedrock that provides some of the most spectacular and fragile surface waters in the state. The Howard County watershed is six miles long and encompasses 11,600 acres within the Upper Iowa Watershed, which contains 14 lakes and 1,429 miles of river.
Landowners Take the InitiativeIn 1992, landowners in the watershed joined with federal, state and local agencies to create the Bigalk Creek Water Quality Project. The project has five goals: to create awareness of fertilizer and pesticide use impacts, to demonstrate the feasibility of several innovative resource management systems, to reduce streambank erosion, to reduce sedimentation and to reduce the amount of livestock manure reaching the stream. Landowners’ restoration efforts near the trout stream have included tree plantings, implementation of streambank stabilization measures, construction of a cattle crossing, installation of fish habitat structures and utilization of innovative nose pumps for livestock watering. Farmers have also erected permanent fencing, including a solar-powered electric fence, to limit cattle access to the stream system. Upland management practices to control runoff have included construction of sediment basins, imple-mentation of no-till and strip-cropping farming systems and establish ment of contours and grassed waterways. Governmental agencies have supported local actions with their own initiatives to restore the stream corridor. The USDA Conservation Reserve Program has worked with landowners to install riparian buffers and filter strips along the stream. The Iowa Department of Natural Resources (DNR) and the Department of Agriculture and Land Stewardship Division of Soil Conservation have contributed technical expertise and funding to reshape the streambanks, construct fish hides, re-seed vegetation in the area and install rock riprap, a combination of various materials, such as concrete blocks and rubble, intended to prevent flooding and erosion. The Trout Return
The Bigalk Creek Water Quality Project has surpassed many of its original goals. Sediment delivered to the stream has been reduced by 50 percent. The creek’s annual sediment load from erosion has deceased by 5,000 tons -- a 60 percent reduction. Livestock manure reaching the stream has been reduced by 50 percent. These reductions have brought about a noticeable improvement in water quality and slowed algal growth. More Progress to Come
http://water.usgs.gov/owq/cleanwater/success/bigalk.html |
Land located above the trout
stream in the Bigalk Creek
Watershed is used predominantly
for agriculture. In recent years,
uncontrolled livestock access to the
creek has significantly diminished
the fish population. Livestock overgrazing,
sedimentation and stream-bank
erosion have degraded pool
habitat and reduced instream vegetation.
Also, the creek’s geological
composition, fractured limestone
bedrock covered by a thin layer of
soil, potentially allows agricultural
inputs such as fertilizers, pesticides
and manure to leach through the
soil and contaminate groundwater.
The USDA Natural Resources
Conservation Service classifies all
of the cropland near the fishable
section of the stream corridor as
highly erodible, with a high potential
for sediment to reach the
stream channel.
The extensive effort made in Bigalk
Creek has enjoyed tremendous success.
A July 1999 DNR creek survey
counted 80 rainbow trout, representing
a 600 percent increase
from an identical 1992 survey. The
same survey noted that 20 percent
of the fish were naturalized -- they
had been in the stream long enough
to acquire their natural coloring or
were naturally reproduced. The
results make the Bigalk Creek only
the third stream in Iowa with documented
natural rainbow trout
reproduction. A follow-up survey
in October 1999 documented 150
naturalized rainbow trout per mile
of stream, the highest number of
wild rainbow trout ever documented
in an Iowa trout stream. The
surveys also detected the presence
of invertebrates, another key indicator
of stream health.
Landowners have found best man-agement
practices to be both ecologically
and economically reward
ing, and future use of BMPs should
continue improvement of Bigalk
Creek’s water quality and fish habitat.
A 1998 effort, the Bigalk to
Bohemian Water Quality Project,
will use integrated crop management
techniques to further reduce
the potential for agricultural contaminants
to leach into water
resources. Targeting 83,000 acres in
Howard County, the project has
shifted the emphasis of restoration
efforts from surface water to
groundwater concerns.