With the mighty Red River flowing through the heart of two cities, planning for flood protection after what is now known as “The Flood of ’97,” has not been an easy task.
Grand Forks, ND, and East Grand Forks, MN, are separated only by the mighty Red River. Together the two cities have a population of approximately 60,000, more than 50,000 of which is in Grand Forks.
Flooding is not an uncommon occurrence in the two communities, as two major floods have occurred in recent years, where the Red River reached a height of approximately 50 ft. (15 m). As a result, city officials have experience handling that much water. Flooding, though, has been common along the Mighty Red for more than 100 years. However, in 1997, floodwaters reached a level of 64.5 ft. (20 m).
This flood was more than the cities bargained for.
More than 100 in. (254 cm) of snow fell during the winter of 1996-97 and a late, sudden spring thaw, contributed to the horrendous flood. Also attributing to the flood were drainage projects throughout the Red River Valley, causing runoff to flow into the Red or into other rivers that flow into the Red.
The two cities are located on the northern edge of the Red River Valley. Since the Red flows north and all the cities along the Red had built up dikes to keep the water out of their communities, a huge influx of water, with nowhere else to go, raced toward the cities. Floodwaters rushed over and washed out dikes, dikes that had been built up that spring to withstand the “normal” 50-ft. (15 m) flooding. Both cities were evacuated, homes and businesses were inundated and covered with water.
Only seven of the East Grand Forks’ approximate 2,400 homes were not damaged in the flood. Of the damaged homes, 690 had to be demolished, causing many residents to move away, creating a population drop of approximately 1,800. East Grand Forks’ previous population was approximately 8,500. “Some people have chosen to build new homes elsewhere or simply move away,” said Gary Sanders, consulting engineer of the diking project, of Floan-Sanders Inc. The city’s main business district lies downtown and was heavily damaged.
So, to give the remaining population and business owners some security and peace of mind that devastation of this magnitude wouldn’t happen again, East Grand Forks constructed an invisible flood wall. The flood wall protects the city’s downtown area, much of which has since been reconstructed or relocated, and allows excess flood water to flow into lands where homes were removed. Those areas have been turned into 1,200 acres (486 ha) of parks and recreation area.
Now, five years later and with much study and planning by the U.S. Army Corps of Engineers and debate within Grand Forks, ND, construction of a permanent dike system, which will protect both communities, is under way. Grand Forks, the larger of the two cities, debated at length on what type of flood control plan would be best, to where flood water should be diverted (around the city had been considered), and where should the dike be located. Residents stated they didn’t wanted their homes to be located on the wet side of the dike.
A $390-million joint project between the two cities and two states, was decided on that will incorporate the existing floodwall in East Grand Forks. It requires building an earthen levee and additional floodwall to protect both communities from high water, and an internal drainage system to collect water in a hole that would be drained periodically. Diverting water from other waterways within each community is another major part of the overall project.
The project is expected to take up to nine years to complete, even on its escalated schedule, said Mark Walker, assistant city engineer for the city of Grand Forks. “The acquisition of federal funds may slow the completion. The President’s budget, at this time, doesn’t include the amount that had been appropriated by the Senate, so the funding won’t come as quickly.” In this case, it is necessary to spread the project over several years, easing the annual costs. State funding is in place.
Dike System
The dike system consisting of several miles, 12 in Grand Forks and 18 in East Grand Forks, is being constructed simultaneously on both sides of the river, in order to cover each community without leaving one in danger while the other is protected, Walker noted.
Sanders added that since the most common flood level is approximately 50 ft. (15 m) the diking system is being constructed to handle that level.
“The city has realized from other floods that they can add height [to the dikes] with sandbags,” Walker said. The clay dike has varying widths at the base but is 10-ft. (3 m) wide at the top.
The majority of the dike will be constructed of clay, but in some areas a floodwall will be built. For example, the floodwall is planned for an historic neighborhood with finer older homes, Walker said. “To build an earth levee would mean wiping out some of those homes. There are also some unstable areas of riverbank where floodwall will be used. The wall is lighter weight and narrower than an earthen dike and so less of the neighborhood will have to be purchased and moved or destroyed.”
Floodwall technology has changed since a previous flood protection plan from the 1960s was constructed, which included a floodwall that is plain in appearance, Walker explained. “On this project we’re using some new technology. The Corps has designed form liners that produce a number of different patterns and make the concrete wall look like stone; or stains can be used to make the wall look like limestone, so it doesn’t look like an ugly gray wall.”
The height of the earthen dike varies in different locations, reaching heights of 16 to 18 ft. (4.8 to 5.5 m). “The dike level varies because of the varying levels of the river bank, but the protection is comparable,” Sanders said. “One reason the dike is so tall is that the Corps has determined that they are trying to design for a certain flood event and the levees have an added safety factor, or free board area. The levees are being built up to 5 ft. higher than the 50-ft. level the water generally reaches, so there is some additional protection.
“The levee system follows the river and for a ways on the north and south ends of town there is a tieback levee that ties into high ground, so flood waters can’t come around and flood you from behind,” Walker added.
Water Diversion
But a dike system alone won’t cure the two cities’ flood problems. Each community has additional water systems that cause ongoing flood problems. In Grand Forks, the English Coulee overflows, increasing the devastation within the community.
Part of the overall flood control project consists of diverting some of the water that would normally flow through Grand Forks into the English Coulee. The English Coulee diversion project was awarded to Gowen Construction of Oslo, MN. “They are building a channel that is 8 or 9 mi. long, consisting of new channel and widened channel,” Walker said. “Our problem is the Coulee is tied into the Red River and when it came up in ’97 the water backed up into town through that Coulee. … So half the flood fight was against the river and the other half was against the Coulee.”
The purpose of the diversion is to divert water through the Coulee so a smaller pump station can be built. Walker explained that during a flood event, if the river accepts all the water an enormous flood station is needed. So, though the project seems much larger and more costly when adding the Coulee portion, it is actually less costly, he said.
In East Grand Forks, the Red Lake River causes similar problems as the English Coulee. During a flood situation East Grand Forks becomes two islands, one on the north and one on the south side of the Red Lake River, Walker noted. The 18 mi. (29 km) of diking on the Minnesota side will ring both ends of the city so an island won’t be created. “In the flood of 1979, the south end of town became an island. In the flood of 1997, the south end became part of the river,” Sanders said.
Phase Work
So far, home purchases and relocation of infrastructure have been completed, along with placing rip rap around a dam to prevent further erosion, and converting a low-head dam to a rock rapids. The first phase, which includes construction of half the diking, is to be completed by October. Strata Corporation of Grand Forks, is the general contractor of the phase one work.
Currently bids for the second phase are being awarded. Walters said that during the second phase the cities hope to build the majority of the floodwalls.
The third phase will include bidding the pump station and closure of the English Coulee, Walter added. Phase four focuses on the Hartsville Coulee in Grand Forks. If the river gets high enough it starts flowing through this little Coulee.
The target is to finish the flood control features by the end of 2004 so they can be used for possible flooding during the spring of 2005, Walker noted.
In each phase there are unique situations to deal with. Walker explained that on the north end, which has a lower elevation and older homes, there is an elderly housing development to protect that at one time was a hospital and now has historical significance. The southern end of the city has newer homes that are on a higher elevation.
Both cities are basically trying to keep their communities in tact. In East Grand Forks, the majority of the businesses are located close to the river, many of which have been refurbished or relocated, and many homes were lost.
The population loss in East Grand Forks, however, didn’t necessarily mean a decrease in tax base. “Since then we have lost a lot of younger people and older retired people. When their homes were gone they chose to make lifestyle changes. We lost lower priced housing but new homes are being built with a higher value, which created a significantly higher actual tax base, Sanders said. “Our hope is that in the next 20 years the population will increase to where it was, or higher. We have a new City Hall, a new restaurant, a Cabela’s store, a refurbished mall and a significant amount of housing programs to rehab housing and a program for someone building a new home.”
In Grand Forks, a much larger community, businesses are spread throughout the community, as well as the downtown area, so the effect on the tax base wasn’t as great.
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