Iowa has been the site of some very significant floods throughout the years. Two floods recently caused major damage and disaster…1993, 2008.
The Great Flood of 1993 was among the most costly and devastating ever to occur in the United States, with $15 billion in damages. The 1993 flood even surpassed the 1927 flood, at the time the largest flood ever recorded on the Mississippi.
Then the most recent Flood of 2008…called the 500-year Flood. This flood impacted nearly the entire state especially hit hard was the Eastern part of the state. While the Great Flood of 1993 was greater in continental terms, in local Iowa terms, the June, 2008 Midwest floods were considerably worse. Lessons learned in 1993, however, helped prevent or otherwise ameliorate damage, extensive as it was; one example is how the city of Des Moines raised its levee around its domestic water and sewage treatment plants.
A great website to watch the levels of rivers and lakes during these events is www.rivergages.com This website can provide vital information on current levels of water and helps communities prepare. Iowa is located in the Rock Island District.
The coordinates will take you to the Beaver Creek Gage located in Polk County, IA on the left bank, 10ft upstream from the NW 70th Ave bridge, 0.5 miles downstream of Little Beaver Creek, 2.5 miles east of Grimes, 6miles above the mouth of the Beaver Creek. This particular gage is considered to be in the Des Moines River Basin. Flood stage for this Beaver Creek Gage is 12.0ft. The highest level recorded at this gage was during the Great Flood of 1993. This gage reached 16.58ft on July 10, 1993.
LOCAL GEOLOGY: The area surrounding the Beaver Creek is mostly farm land. This area floods very easily because of the topography. This site is approximately 826 ft elevation. The river itself has very small banking therefore once the water comes out of is banks the flooding begins to the immediate East. The elevation begins to drop and thus causing the fields and roads to begin to flood. The area immediately to the west and the next 2 miles of the river the elevation to the west rises over 100ft. This causes a ramping effect of the river to go into the low lying fields.
In times of heavy flooding these gaging stations along the creeks and rivers surrounding the city are vital in the early warning of potential flooding of low lying areas along the Beaver Creek and the other rivers of Polk County and further downstream
To get credit for this cache you must do the following:
1. Post a picture with your log on the south bridge with your GPS
EMAIL THE FOLLOWING ANSWERS TO ME, DO NOT POST IN YOUR LOG:
2. While on the bridge calculate the current width of the creek. You can do this by making a way point at one edge of the creek and walking across the bike path until you get to the next edge of creek.
3. Remembering the website I mentioned and the District and Basin this gage is located. What is the current depth stage of this gage while you were doing this Earthcache?
4. Remembering the website I mentioned and the District and Basin this gage is located. During the 500-Year Floods of 2008, the highest recorded level was almost broken. How high (in hundredths) and what day in 2008 was the peak of this Beaver Creek Gage?
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