Promote watershed-based flood management

By William A. Ehm

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Iowans have recognized the value of comprehensive flood plain management policy since the devastating floods of the 1950s. A flood plain management symposium in 1968 included public servants, educators, economists and engineers. The strategies that emerged there are still in use today.

Iowa at all levels of government has invested in three strategies to reduce risks of flooding: modify flooding through structural approaches, modify susceptibility to flooding and modify impacts of flooding.

l Our structural levees, dikes and dams are aging. This infrastructure must be maintained and improved if we expect it to protect us into the future.

l We must recognize that regardless of the infrastructure in place, floods will occur. The flood plain must be allowed to convey water; the more development in flood plains, the greater the risk for damages and loss of life.

l When development occurs in the flood plain and structural strategies fail to protect us, we must rely on flood insurance, federal disaster assistance and buyouts of flood-damaged properties to mitigate the losses that occur.

Like a three-legged stool, if one strategy weakens, such as a lack of funding to repair levees, flooding risks increase unless the other two strategies' capacity is increased.

After the 2008 floods, the Iowa Water Resources Coordinating Council (WRCC) was charged with making recommendations that promote “a watershed management approach to reduce the adverse impact of future flooding on this state's residents, businesses, communities, and soil and water quality.” The Council solicited information from hydrological and land-use experts, representatives of cities, counties, drainage and levee districts, agricultural interests, soil and water conservation districts, and other urban and regional planning experts.

The Council's recommendations and progress so far:

l Iowa's critical infrastructure should garner additional flood protection. Facilities that are critical to the health and safety of the public, such as emergency operation centers, communication centers and hospitals, should be located and designed to maintain their function during major flood - one with a 1 in 500 chance of occurring in any given year - whenever practical.

l Opportunities should be explored to implement minimum statewide stormwater laws and regulations to reduce water runoff.

l Where feasible, channeled streams should be returned to their natural meander.

l Soil health in agricultural fields and at construction sites should be improved to more readily infiltrate rainwater and snowmelt in order to reduce runoff.

l Water retention strategies, such as rain gardens, swales, rain barrels and permeable paving, should be promoted to reduce runoff.

l The Iowa Flood Center's research and engineering needs and the Department of Natural Resource's (DNR) flood plain management section should be financially supported.

Based upon the Water Resources Council recommendations, Iowa has formed a chapter of the Association of State Flood Plain Managers to provide local managers and planners a vehicle to discuss flood plain issues and learn from each other. Iowa State University Extension will provide flood plain management information to the public

Iowa should promote watershed-wide flood management to provide a holistic approach to reducing flood damage. Water retention opportunities, such as allowing water to flow onto re-established wetlands or less valued lands, could save high-value lands downstream. Already the Iowa DNR is assisting the establishment of watershed management authorities and the Iowa Flood Center is analyzing and predicting watershed changes that can reduce the impacts of flooding.

Many factors must be considered and strategies researched for watershed-based flood management to be beneficial and cost effective. Experience has taught us this: When the environment is altered, there are risks and consequences not easily foreseen. Comprehensive thinking can improve the success of flood management strategies.

The risk is in what we fail to understand and make decisions nonetheless.

William A. Ehm is Environmental Services Division Administrator, Iowa Department of Natural Resources. Comments: William.Ehm@dnr.iowa.gov

Flood symposium

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l What: “Five years out: Ongoing impacts and challenges of the 2008 floods”

l When: 8:30 a.m. to 3:30 p.m., May 31

l Where: National Czech & Slovak Museum & Library, Cedar Rapids

l Get Involved: The public is encouraged to attend. More information at http://ppc.uiowa.edu/forkenbrock/five-years-out.

l Related event: “Trouble the Water” art exhibit and reception, CSPS Hall, Cedar Rapids, 7-9 p.m., May 30 (no registration required)