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Hills RC&D 712 South
Highway 6
P.O. Box 189
Oakland, IA 51560-0189
Map to our location in Oakland
Phone: 712.482.3029
Fax: 712.482.5590 |
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Photo Gallery
This map shows the 22 counties in western Iowa that are eligible to receive funds from the Hungry Canyons Alliance to prevent streambed degradation. It takes a joint effort between landowners, counties, and state and federal government to protect degrading streams. You can see that the headcut of a large gully is moving upstream. This is a closer view of what the gully looks like. As the streams downcut, the banks will continue to erode back. Because of the fine texture of loess, loess soils hold moisture and may not drain quickly. As streams downcut and the banks erode back, bridge pilings are exposed. If bridge pilings are exposed, the bridge will not be able to hold as much weight. The road leading up to this bridge has collapsed because the stream eroded the bank away underneath it.
This bridge's pilings fell away causing the bridge deck to collapse. This bridge has been completely destroyed.
The federal government provides funding and technical assistance. The state government provides funding and sets regulations. The counties and landowners pay their share and carry out the engineering and construction of each structure. A nickpoint beginning downstream in a watershed may affect the entire watershed as it erodes its way upstream. Thus, it is helpful to think of the placement of streambed stabilization structures on a watershed scale. This way planning of site locations and anticipation of infrastructure endangerment or protection can be dealt with across county lines. This is a nickpoint. It will continue to erode and advance upstream until the streambed becomes stabilized.
At right is a structure in Pottawattamie County which is an excellent example of a completed structure in the Hungry Canyons Alliance Program that protects a bridge on a heavily used county highway. It has two weirs that take out five feet of grade each. The structure is located in the left central portion of the left picture. This photo shows the benefits of a Hungry Canyons Alliance streambed stabilization structure. Downstream of the structure, the streambed contains nickpoints and the banks are unstable and slumping. Upstream of the structure, the streambed and the banks appear to be stable. You can see that the headcut of a large gully is moving upstream and more of the field is in great danger of being lost. To give you an idea of the growth of the gully, the farmer did not farm up to the edge, but rather the gully has eroded back. Note the volume of soil that has been eroded away. Tons of soil are eroded from fields each year by gullies.
This is a closer view of what the gully looks like. We are looking over the headcut, (in the foreground of the photo) or waterfall, out into the gully. The gully is about 25-30 feet deep and has actively eroding banks which are slumping into the gully.
As the streams downcut, the banks will continue to erode back. Once the streambed has become stabilized, the banks will erode back to a stable slope. Bank erosion is caused by groundwater seeping through the banks and by streams scouring the banks
Because of the fine texture of loess, loess soils hold moisture and may not drain quickly. When vertical banks become saturated, the banks are unable to bear the weight of the water and may topple or slump. Here, a tree has toppled over into a gully after a heavy rain.
As streams downcut and the banks erode back, bridge pilings are exposed. New extensions and pilings may be added to the bridge to keep it in use. However, in this case, both sets of bridge pilings have become exposed.
If bridge pilings are exposed, the bridge will not be able to hold as much weight. Weight limit signs will then have to be posted, causing detours for heavy farm equipment
The road leading up to this bridge has collapsed because the stream eroded the bank away underneath it.
This bridge's pilings fell away causing the bridge deck to collapse. This bridge collapse could result in the loss of life if approached before warning signs could be established.
This bridge has been completely destroyed. If the county funds are low, this bridge may not be replaced. This causes long detours for those living in the area and public services, such as school buses.
This map shows the 22 counties in western Iowa that are eligible to receive funds from the Hungry Canyons Alliance to prevent streambed degradation.
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Status of
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(MS Powerpoint presentation)
For information about the Lewis & Clark Passport Education
Program...Read
here.
Updated schedule and listing of Western
Iowa Grape Growers Association educational sessions can be found
here.
"Cartography:
A Lost Art" presentation given at 2004 SLUG-Fest in Sioux City
can be downloaded by following the link. |
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Upcoming
Events |
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January 31st, 2005 |
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RC&D Board Meeting
Oakland, IA |
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February 5th, 2005 |
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Local Foods Conference
Atlantic, IA |
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February 8th -10th,
2005 |
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Prescribed Fire
Conference
Ames, IA |
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February 21st, 2005
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President's Day
RC&D Office Closed |
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March 4th, 2005 |
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Hungry Canyons
Quarterly Mtg
Location: TBD |
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April 3rd - 5th, 2005 |
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North Central Regional
RC&D Meeting
Dubuque, IA |
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