While many regions of the U.S. are experiencing extreme flooding this season, Dayton will be largely unaffected by these spring floods.
Natural and man-made flood preventions around the Dayton area will keep the city safe from extreme flood waters.
The Miami Conservancy District (M.C.D.) has been protecting Dayton and keeping its groundwater supply safe since the Great Dayton Flood of 1913. The M.C.D. has built levees and dams throughout the area to divert and restrict water flow, respectively, and prevent specific places from flooding.
“[The MCD is] greatly reducing flood risk for 48,000 people,” said Angela Manuszak, the special projects coordinator at the M.C.D.
While these systems work well in preventing floods from hitting populated areas, the water that falls and runs into rivers and streams still overflows the beds when flooding is extreme. This is when the natural flood preventers come in to play.
When any sort of rain or snowfall occurs, that water eventually gets absorbed into the ground. The Great Miami Buried Valley Aquifer beneath Dayton can absorb enough water to keep the floods under control while man-made systems are helping at the same time.
This aquifer is an underground system of fresh groundwater that when pumped through wells is used as a water source for Dayton and surrounding areas. Aquifers do not dry up because they are replenished by rain and snowfall.
Dr. Allen McGrew, professor of geology at the University of Dayton, said that an increase in the intensity of rain, and therefore storms, is occurring globally.
High intensity rain causes more runoff, which causes flooding on the surface. When the ground is too saturated to take any more water in, the water bounces off and creates runoff.
Massive amounts of rainfall and snowfall at one time raise the water table, the highest point, of the aquifer. The heavy rains experienced this spring will slightly raise the water table.
The constant water pumped from it supplies 2.3 million people with clean water in southwest Ohio, according to the M.C.D. This means that there is room for extra water to flow in when we have torrential storms.
“[The aquifer level] basically increases from about the end of November, or December, through May,” said University of Dayton professor Dr. Zelalem Bedaso.
The water table of the aquifer fluctuates throughout the year according to the seasons due to the snow from the winter slowly and continuously melting into the ground. Heavy storms in the spring continue to add to the heighted water supply.
Aquifer levels fall during the other half of the year due to temperature changes. However, global warming could disrupt this equilibrium more than it already has.
“We expect [the aquifer] to increase in the future if precipitation increases without temperature increase,” Bedaso said.
This means that if rain increases without temperature increase, the surface water will take longer to evaporate and more of it will sink into the aquifer.
The precipitation increase happening now is leveled out by temperature increasing at the same time. Water evaporates faster in warm weather, so the relationship between rainfall and heat is projected to keep the aquifer level steady.
The preventative measures that Dayton has taken to protect against flooding due to its history will help us get through this wet spring with the city and water supply intact.