Nebraska is allocated 1.1 million acre-feet of water from the North Platte River each year to meet irrigation needs. Located at the Wyoming-Nebraska border, a U.S. Geological Survey (USGS) weir measures the amount of water leaving Wyoming and entering Nebraska to make sure the correct amount is delivered. This is one of the most accurate and precise USGS measurement stations.
However, diversions upstream have caused the river to cut new paths and alter water movement downstream. In recent years, the river has formed an S-shaped route a short distance upstream from the measurement weir and has caused the riverbanks near the gauging station to erode, threatening to bypass the weir itself.
Bendway weirs were installed along the north and south riverbanks to slow down flows, reducing bank erosion and protecting the measurement weir.
The bendway weirs consist of large rock piles and bags filled with sand from the river. The rocks are placed next to the riverbanks, which act as interference and slow down the water. The sand bags protrude further out into the river channel and anchor into the riverbed.
Over time, they become part of the natural system by establishing vegetation and acting as part of the riverbank.
The bendway weirs were installed in February and March of 2013, and have already started to anchor to the riverbed and encourage native vegetation.
Over time, the bendway weirs are expected to become more vegetated. Deposited sediment will fill in between the bendway weirs, further directing the stream flow over the gauging station and weir.
Sierra Harris was a PBT intern and staff member from 2011 through 2014 while she was a student in the University of Nebraska-Lincoln’s School of Natural Resources.