Reitan: Spring melt preparations begin as snow fades
West Fargo city crews have begun spring melt preparations as temperatures warm and snow begins to melt. Crews have been inspecting and testing storm sewer lift pumps, emergency generators and portable pumps to ensure proper operations. Inlets to catch basins and culverts are being cleared to allow proper drainage. The city will install gauges to monitor river levels as river flows increase. They will also contract for and stage excavators near box culverts and bridges south of Interstate 94 to clear ice and debris from the upstream side of river crossings.
The Army Corps of Engineers set preparation for flooding along the Sheyenne River Basin into motion with releases from Lake Ashtabula north of Valley City beginning the first part of March. The releases are meant to allow for additional storage capacity above Bald Hill Dam. The released water also assists in breaking up ice in the river channel from below the dam to where the Sheyenne joins the Red River. The Army Corps of Engineers attempts to time the draw down so the releases are halted before the normal run off conditions start.
As snow melt and run off increases city crews will begin with the operation of the Horace- West Fargo Diversion. The diversion actually consists of five control structures and two separate channels. The longest channel begins just southwest of Horace. At the mouth of the Horace diversion channel is the first control structure, a small dam meant to keep normal river flows within the existing river channel. As flood waters rise the dam is overtopped and water enters the diversion.
The second control structure at this location is a set of box culverts which controls the amount of flood waters that can remain within the Sheyenne River channel. Once flood waters rise to the maximum allowable flow within the river channel the additional water is forced into the diversion. Flood water entering the Horace branch of the diversion travels north to Interstate 94.
Flood waters remaining within the Sheyenne River channel flow north through Horace and into West Fargo. Just south of Interstate 94 the third control structure is located west of Sheyenne Street and in the mouth of the West Fargo branch of the diversion. The structure is a small dam meant to keep normal river flows within the Sheyenne River channel. Once river flows rise to flood stage water begins to overtop the small dam and enter the West Fargo branch of the diversion. Flood water in the diversion flows to the northwest where it joins the waters of the Horace diversion. The combined flows continue to the north until they re-enter the Sheyenne River channel north of West Fargo.
A fourth control structure is located in the Sheyenne River channel just before the river crosses under Interstate 94. The control structure consists of gates located at the inlets of the box culverts crossing under the interstate. Under an operations agreement with the Army Corps of Engineers and the Diversion Authority the gates are closed during periods of high water and all flows are directed into the West Fargo branch of the diversion. Once the gates are closed the only water able to enter the river system north of the interstate is the runoff occurring within the city of West Fargo.
The final control structure is located in the river channel north of 12th Avenue North and at a point where the diversion reenters the river. Here a dam prevents water from flowing back into West Fargo. In addition, large pumps lift water from the city side of the dam and discharge it back into the river channel. Without the pumps the city would be flooded by runoff from the melting snow or from rain falling within the city.
The other components of the flood control system include a series of dikes along the river and diversion channels; storm water pumps to move water from the protected areas; and gates on culverts to prevent water from flowing back into the protected areas. The combination of all the components of the diversion system and the proper orchestration of operation in accordance with the Army Corps of Engineers Operating Plan protects the communities of Horace and West Fargo from a flood event.
A number of years ago a group of people came together with an idea to do flood fighting differently within West Fargo. Their decision to mitigate the flood threat through a diversion system met with resistance at the time. The group fought through the resistance to show the value of their plan and won the election to put the plan into motion. Time has proven the decision to be the right one and one that dramatically changed the future of Horace, West Fargo and the area in between.
Reitan is West Fargo assistant police chief.