|EERC Waffle plan could have reduced 1997 flooding|
The Energy & Environmental Research Center has announced that soon-to-be-published results regarding the EERC’s Waffle storage plan indicate that had Waffle storage been in place during the 1997 flood, the peak flows in the Red River could have been reduced by up to 5 feet in Grand Forks and East Grand Forks, enough to prevent the dikes from being overtopped. The decrease in peak flows could be further enhanced with minor changes to roads and other infrastructure.
Other points along the Red River would also have experienced significant reductions in peak flood crests as a result of Waffle storage. EERC results indicate that up to a 4.5-foot drop in peak flows could have occurred in Fargo. Waffle modeling results predict as high as a 59 percent reduction in peak flows within various tributaries of the Red River.
“This would have saved many homes and businesses in Grand Forks and East Grand Forks and averted much of the $2 billion in flood-related damages accrued in 1997,” said EERC Senior Research Manager Bethany Kurz. “Overall, the utilization of Waffle-type storage would have significantly reduced flood levels throughout the entire basin,” Kurz said.
The Waffle project, which the EERC launched in 2002, is the largest, most comprehensive evaluation of an innovative, basinwide flood mitigation strategy ever conducted for the Red River Basin. The main goal of the project, initially funded by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), was to determine the feasibility of utilizing a basinwide system for temporary storage of floodwater in the basin to help mitigate large, springtime floods.
Described as “the blinding flash of the obvious,” by EERC Director Gerald Groenewold, champion of the Waffle concept and the person who coined the term “Waffle,” the strategy provides basinwide flood protection for farmsteads, small towns, and urban areas.
“The Waffle concept was developed in the wake of the most devastating climatic event to hit our valley in recent history,” Groenewold said. “The Waffle received its name because, just as squares on a waffle hold syrup, the grid work of existing roads in the region can be used to store water.”
The storage areas, roads, and drainage structures would act as a network of channels and control structures to temporarily store water until the flood crest passes. The Waffle could also benefit landowners and farmers during dry periods to provide soil moisture needed during the early part of the growing season. Results demonstrated a higher rate of frost removal from soils in areas of water storage. As a result, moisture levels in the soils were higher and lasted longer into the growing season compared to nonflooded areas. This could provide a means of replenishing groundwater supplies during periods of drought.
“Because water, mainly in the form of snowmelt, is stored where it falls and drainage is controlled, the Waffle not only slows springtime runoff rates, but also reduces the total runoff volume by allowing some of the stored water either to evaporate or soak into the soil,” said EERC Associate Director for Research John Harju.
This controlled drainage would also save many county roads. Following major flood events, some counties spend upwards of $1 million to repair damaged roads from washouts. By helping control springtime runoff and reducing total runoff volumes, the Waffle could help prevent widespread infrastructure damage. One landowner witnessed this benefit downstream of the Waffle’s Lake Bronson field trial site, one of four demonstrations conducted during the course of the study. “This was the first time I can remember that the road going to my house was not flooded,” he said.
According to an extensive landowner survey, about 46 percent of landowners/farmers in the Red River Basin would be interested in participating in the Waffle storage program. Another 30 percent were undecided.
“The Waffle plan, if implemented, could offer long-term security from floods like the one in 1997 and provide necessary augmentation to conventional flood mitigation measures to combat even larger floods,” said EERC Senior Research Advisor, Ed Steadman. “This added protection is critical for the region, since most areas are largely unprepared to deal with floods like those that have occurred historically.”
Accounts from the spring of 1826 indicate a flood occurred with flows 30 percent larger than 1997 in Grand Forks/East Grand Forks and 42 percent larger in Winnipeg. A flood with flows 50 percent greater than the 1997 flood would overtop the current Grand Forks levees; however, with the augment provided by Waffle storage, the water level would be reduced to 56 feet, well below the 59-foot level of the current dikes.
“The Waffle project results facilitate overall understanding of basinwide flood protection and provide the framework for a flood prevention model that could be implemented globally,” Groenewold said. “It is the key to the long-term economic vitality of our region.”
The final results from the Waffle study will be published and released by mid-July. -- Energy & Environmental Research Center.