Laserfiche WebLink
rin u r 1 5 TALK a 11 <br />i i ' i <br />ii <br />Leo tsfrie , <br />rea yrl ist <br />During the late fall of 1994, Decoria <br />Township in Blue Earth County undertook an <br />innovative project to combat streambank <br />erosion along the LeSueur River that <br />once again was threatening a township <br />road. <br />Traditional stabilization methods <br />such as the use of riprap were deemed <br />cost prohibitive due to the substantial <br />(50=60' + or -) height and steepness of the <br />bank at this site. Consequently, during a <br />discussion of other possible alternatives, <br />the subject of river training evolved. <br />Despite the lack of precedent for use of <br />this method (we were aware of only one <br />other project). the comparatively law cost <br />and likelihood of success seemed to merit <br />serious consideration. <br />With the support of Blue Earth <br />County SWCD an application was made for <br />cost-share assistance from the state's <br />Streambank, Lakeshore and Roadside Erosion <br />(SLR) grant program. 'This resulted in a grant <br />providing approximately one-half of the project's <br />total cost of $52,000. <br />A Division of Waters' permit was issued <br />authorizing the construction of flriger dikes <br />along 3 sites. Each dike was to measure <br />approximately 60' in length, 5' in height and <br />with a 12' bottom width. The dikes were to be <br />set at a 20' skew from the channel bank to <br />deflect the current away from those areas of <br />severely eroding slopes. <br />concrete chunks and capped off with quarry <br />rock. The average size of the aggregate material <br />measured 24"-36" in diameter to withstand the <br />anticipated high water flows. <br />The project's contractor, Southern - <br />Minnesota Construction of Mankato, faced <br />several hurdles to getting the materials <br />in place. Not least among these was the <br />persistent high flows within the river <br />during 1994 that delayed construction <br />until mid November. The next obstacle <br />was how to get the required heavy <br />equipment down into the channel. <br />Locations for temporary cuts in the bank <br />to `provide access were .eventually <br />selected. A large tracked. backhoe was <br />then able to "walk" up and down the <br />channel bed constructing the dikes after <br />retrieving the aggregate from along the <br />slopes where it was dumped from above. <br />Fortunately, I was able to be present <br />during the installation of the spur dikes. <br />It was a rather remarkable sight to <br />witness the large backhce working in the <br />channel. <br />., . <br />The materials used included salvaged <br />concrete "J" barriers donated by MNDOTs <br />District 7. The barriers were then covered with <br />