Continuing Authorities Program: Aquatic Ecosystem Restoration – Section 1135, Sand Hill River

U.S. Army Corps of Engineers, St. Paul District
Published Feb. 26, 2015
A major reach of the Sand Hill River downstream of Fertile, Minn., was the subject of a flood control project constructed by the Corps of Engineers from 1955 to 1958. It involved straightening the river and constructing four drop structures and served as a drainage improvement to local agriculture. Overall, more than 18 miles of the Sand Hill River was straightened or abandoned. The straightened channel decreased channel length, increased channel grade, increased channel conveyance, and reduced the flood profiles in the lower Sand Hill River watershed. A series of four concrete drop structures were installed in the new Sand Hill River alignment to provide grade control. These grade control structures created six to eight-foot changes in bed grade, but left the river itself impassable for spawning fish.  

A preliminary restoration plan completed in 2003 recommended several measures to improve fish passage in the river including construction of rock structures at each of the Corps drop structures in the river as well as installation of several riffles and pools to decrease the slope of the river and create areas for refuge and rest for migrating fish.

Drop structure on the Sand Hill River

 

Location/Description

The study area is located in a rural setting in Polk County, MN, 275 miles northwest of Minneapolis, MN.  The Sand Hill River basin is centrally located in the Red River Valley Watershed.

A major reach of the river downstream of Fertile, MN, was the subject of a flood control project constructed by the U.S. Army Corps of Engineers from 1955 to 1958.  It involved straightening the river and constructing four drop structures and served as drainage improvement to local agriculture.  Overall, more than 18 miles of the Sand Hill River was straightened or abandoned.  The straightened channel decreased channel length, increased channel grade, increased channel conveyance and reduced the flood profiles in the lower Sand Hill River Watershed.  A series of four concrete drop structures were installed in the new Sand Hill River alignment to provide grade control.

These grade control structures created six- to eight-foot changes in bed grade but left the river itself impassable for spawning fish. 

A preliminary restoration plan, completed in 2003, recommended several measures to improve fish passage.  These included construction of rock structures at each of the Corps drop structures in the river as well as installation of several riffles and pools to decrease the slope of the river and create areas for refuge and rest for migrating fish. 

Background

A feasibility report was approved in January 2014, and a project partnership agreement was executed in October 2014 with the Sand Hill River Watershed District.  A grant from the Lessard-Sams Outdoor Heritage Council helped the Sand Hill River Watershed District fund their portion of the project.  A contract (covering three of the four concrete drop structures) was awarded in fall 2015, and construction was initiated in summer 2016.  The fourth and final concrete drop structure contract was awarded in August 2016. 

Status

The construction was completed in late 2017, and the project will be transitioned to the sponsor in spring 2018. 

Authority

The study is being conducted under the authority of Section 1135 of the Water Resources Development Act of 1986, as amended.  The Sand Hill River Watershed District requested the project by letter dated April 2, 2002.

Fiscal

The 25 percent non-federal share includes lands, easements, rights-of-way, relocations and disposal sites.  

Estimated federal costs                             $3,300,000
Estimated non-federal costs                      $1,100,000

Estimated total project costs                     $4,400,000