Comprehensive Plan to Reduce Flooding in Turkey

The Turkey River Watershed Management Authority has released its comprehensive plan to reduce flooding in the 1.1 million-acre Turkey River watershed

Witold Krajewski worries about that last 10 percent.

The Turkey River Watershed Management Authority has released its comprehensive plan to reduce flooding in the 1.1 million-acre Turkey River watershed. The 20-year, $32.8 million plan — the first of its kind for a watershed of such scale — has a goal of knocking the top 10 percent off flood crests, substantially reducing the cost of major floods.

“Absolutely, the last 10 percent is the most destructive. That’s where the money is,” said Krajewski, director of the Iowa Flood Center, which performed the much of the computer modeling upon which the plan is based.

Krajewski said the two main ways to reduce the flooding effects of heavy rains are to increase infiltration of water into the soil and to construct a system of ponds and detention basins to store water for a more controlled release.

The plan’s water storage component calls for building 300 water and sediment control basins, creating or restoring 50 wetlands and establishing 10 linear miles of riparian buffers.

Methods to increase rainfall infiltration include many of the same conservation practices recommended in the state’s nutrient-reduction strategy — reduced tillage or no-till, cover crops, contour buffer strips, grassed waterways, strip cropping, tree and shrub planting, prairie strips, rotational grazing and the Conservation Reserve Program.

“It’s the same flowing water that causes floods and nutrient pollution,” Krajewski said.

The watershed group hopes the many benefits will make the plan “more sellable” to the Legislature and other potential funding sources, said Rod Marlatt, chairman of the group’s board of directors.

Citing statistics from the Federal Emergency Management Agency, Lora Friest said every dollar invested in flood prevention saves the government $5.10 in recovery expenses. She is executive director of Northeast Iowa Resource Conservation and Development (RC&D), the agency that spearheaded development of the plan.

Ross Evelsizer, watershed planner for the RC&D, said plan developers have not yet established a complete accounting of Turkey River flood losses.

Responding to a recent survey, six communities and one county — out of 23 communities and five counties represented on the watershed management authority’s board — reported flood losses since 1995 totaling $20.7 million. They reported 105 homes lost, 79 businesses damaged or lost and 1,518 road segments, bridges or culverts damaged or destroyed.

That figure, Evelsizer said, does not include losses suffered in other cities and counties within the watershed, extensive agricultural losses or the millions of dollars in federal FEMA funds spent on property buyouts or recovery.

The Turkey River plan stands in marked contrast both in terms of cost and approach to Cedar Rapids’s $600 million flood defense system, which will consist primarily of walls and levees designed to channel floodwaters downstream.

Friest said the board members wanted to treat the underlying issue rather than its symptoms.

Source: Gazette

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• Flood Management
• Governance & Planning
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