The Wild Rice River, a tributary of the Red River of the North,
begins in southeast North Dakota and flows for 250 miles to its end
in the Red about 1.5 miles northeast of here. Even though it drains
an area of 2,233 square miles, it starts as an intermittent stream
and is still fairly small (most of the time) even here near its
end, flowing at an average of 100 cubic feet per second (cfs). Once
its waters join with the Red River, they flow north into Lake
Winnipeg, and then into the Hudson Bay.
The Red River Valley is the ancient lake bed of Glacial Lake
Agassiz. After the retreat of the glaciers 13,000 years ago, the
flat area created by the ice as it retreated north filled with melt
water. At one point, the lake covered up to 177,000 square miles in
much of Manitoba, western Ontario, northern Minnesota, eastern
North Dakota, and Saskatchewan. It actually drained and refilled a
number of times until around 8,400 years ago, when it drained one
last time, contributing up to 10 feet to the global post-glacial
sea level rise. The landscape left behind by the lake is
exceptionally flat and very fertile due to the silt deposited at
the bottom of the lake.
For about half its length, the Wild Rice flows parallel to the
larger Red River, around 3-7 miles west of it. Normally, this is
not a problem. The trouble begins when the Red River Valley starts
to flood during the annual spring thaw. Because of its proximity to
the Red, people living in between the two rivers can find
themselves being threatened from both sides. The flat terrain of
the Valley means that once the river jumps its banks, it can spread
out for miles on either side. During especially high floods, the
two rivers can actually meet and become one large linear lake miles
across, causing a lot of problems for the towns and farms along the
way. During the record flood of 2009, the Wild Rice was
approximately 26 feet deeper than average and had a flow rate of
over 10,000 cfs.
The effects of these floods can be seen along the banks of the
river here. Higher flow rates cause erosion along the banks to
happen faster, as well as making permanent alterations to the river
channel. High water deposits river-borne debris on the banks above
the channel, and scours the landscape clean. If the flood was
recent enough, there will be little to no vegetation on the
banks.
To receive credit for this Earthcache, you must email me
the answers to the following questions. Please include the
name of the cache at the beginning of your email.
1. Estimate the width of the river south of the bridge.
2. Go to the
National Weather Service page for the river gauge near
Abercrombie, ND and report what the current flow rate is in
thousands of cubic feet per second (kcfs), as seen on the right
side of the graph.
3. Look for and describe one feature along the river due to
higher flow rates during higher water.
4. What is the significance of the bridge? When was it built,
and when was it replaced?
Be careful in the area if the river is high. Don't go on the
bridge itself for any reason. The area may be inaccessible during
the spring flood season.
Congrats to Former Hawkeye for the FTF!