FAYETTEVILLE -- Floodwaters don't respect municipal boundaries so planners say a regional approach to flooding is needed as Benton and Washington counties continue to grow and develop.
Jane Maginot, a water quality expert with the University of Arkansas System Division of Agriculture Cooperative Extension Service, said she and her peers usually look at water quality but decided someone needed look at water quantity which led to a committee being formed to look at a regional approach to flood prevention and management.
The changes in land use associated with urban development affect flooding in many ways. Here are a few from a U.S. Geological Survey fact sheet:
• Removing vegetation and soil, grading the land surface, and constructing drainage networks increase runoff to streams from rainfall and snowmelt. As a result, the peak discharge, volume, and frequency of floods increase in nearby streams.
• Changes to stream channels during urban development can limit their capacity to convey floodwaters. Roads and buildings constructed in flood-prone areas are exposed to increased flood hazards, including inundation and erosion, as new development continues.
• Streams are fed by runoff from rainfall and snowmelt moving as overland or subsurface flow. Floods occur when large volumes of runoff flow quickly into streams and rivers.
• The peak discharge of a flood is influenced by many factors, including the intensity and duration of storms and snowmelt, the topography and geology of stream basins, vegetation, and the hydrologic conditions preceding storm.
• Land use and other human activities influence the peak discharge of floods by modifying how rainfall and snowmelt are stored on and run off the land surface into streams.
• In undeveloped areas such as forests and grasslands, rainfall and snowmelt collect and are stored on vegetation, in the soil column or in surface depressions. When this storage capacity is filled, runoff flows slowly through soil as subsurface flow. In contrast, urban areas, where much of the land surface is covered by roads and buildings, have less capacity to store rainfall and snowmelt. Construction of roads and buildings often involves removing vegetation, soil, and depressions from the land surface. The permeable soil is replaced by impermeable surfaces such as roads, roofs, parking lots, and sidewalks that store little water, reduce infiltration of water into the ground, and accelerate runoff to ditches and streams.
• Dense networks of ditches and culverts in cities reduce the distance that runoff must travel overland or through subsurface flow paths to reach streams and rivers. Once water enters a drainage network, it flows faster than either overland or subsurface flow.
• With less storage capacity for water in urban basins and more rapid runoff, urban streams rise more quickly during storms and have higher peak discharge rates than do rural streams. In addition, the total volume of water discharged during a flood tends to be larger for urban streams than for rural streams.
• Sediment and debris carried by floodwaters can constrict a channel and increase flooding. This hazard is greatest upstream of culverts, bridges, or other places where debris collects.
• Common consequences of urban development are increased peak discharge and frequency of floods. Typically, the annual maximum discharge in a stream will increase as urban development occurs.
Source: U.S.G.S.
"It kind of came up to start talking about this idea of regional floods, not just as in flood control but flood help, how to help other communities that are having issues with flooding and how to help them try to not have as many flooding issues," Maginot said earlier this week. "We thought why don't we pull together some people and see what the interest is. Are there cities out there that need help with flood control? Are there communities out there can benefit from some kind of regional flood management program? That's really what today is, it's just a starting point to determine the interest and the feasibility and what that might start to look like."
Studies have shown that if it rains one inch over an acre of forest you get about 720 gallons of runoff, Maginot said. If it rains over an acre of parking lot, you get 27,000 gallons of runoff.
About 40 representatives from area towns, cities, the two counties and water-related organizations gathered Tuesday at the Northwest Arkansas Regional Planning Commission to discuss potential benefits and obstacles of a regional approach.
There have been a number of major floods in Northwest Arkansas since 2008 and planners expect things to only get worse as more people move to area towns and cities and more homes, commercial areas, roads and parking lots are built.
In recent storms, flooding has caused an estimated $500,000 damage to one golf courses at Bella Vista, flooded residential areas in Johnson, floated a mini van on the main drag in Lincoln and damaged bridges and roads in rural Washington and Benton counties, to name just a few. Two people, a little girl and an elderly man, recently drowned after being swept away. Residents also report flooding in areas that never used flood.
"We're seeing that more and more frequently. I've worked for Bella Vista for eight years and we've had just about as many floods," planning director Chris Suneson said.
Kevin Gambrill, with Benton County planning, said county issues relate to being downstream.
"We have some particular hotspots. The unincorporated county ends up getting the brunt of the runoff that comes from the cities because it runs down the Illinois particularly, there are a couple of other big ones but the bottom of the Illinois River watershed, those USGA stream gauge data history is getting bigger and bigger during each of these events. I have nine and ten foot high water marks in a particular neighborhood. It's not getting any better."
Gambrill said anything that can be done upstream to reduce flooding would be beneficial and at least maintain the status quo and not make things worse than they already are.
Nathan See, with the city of Pea Ridge, said his city has the same problems in reverse.
"A lot of that problem we have is coming from the rural areas carrying those trees and stuff that the farmers may have moved out of their fields or whatever from the banks," See said. "It's gonna grab all that stuff and bring it down to the Peck Road bridge and just closes it up. That debris is ridiculous. Of course it's going to go over the bridge and once if goes over the bridge, it just covers the whole bottom of the golf course. We've got to get into where this problem is actually coming from."
Gambrill said he has tallied flooding calls to emergency management.
"When I looked at it on a map, it's very random, it's very spread out. The water decides it's going to go to the lowest spot and it's gonna impact an old development. It's everywhere. There's absolutely no pattern to whether it's in a flood plain or not in a flood plain," Gambrill said. "It's truly random at least based on a sample."
To date, each local entity has tried to deal with flooding issues in it's own way without a coordinated effort.
"We need regional storm water detention," said Jerry Morrow, from the city of Johnson. "Creeks don't care about city limits, creeks are going to do what they do and if you keep increasing hard surface, you're gonna increase runoff. This is not a new problem, it's new to us because we're just now growing and all indications are we're going to keep growing. Now is the time to set measures in place to fix it so it doesn't happen."
Morrow said recent flooding in April was such an extreme event it's probably not financially feasible to try and build for a repeat but cities can plan and build for a more typical flooding events.
"Set up regional detention. Set up channelization. You can do various things," Morrow said. "Everybody's got to work together on this."
Morrow said engineers who design subdivisions typically design to the minimum city requirements for that specific development and don't look at the cumulative effect downstream.
"Many of the ordinances in place are creating the problem," Morrow said.
Fixing the problem promises to be expensive and with many other pressing issues, finding money for flooding fixes could be the biggest obstacle, said Don Marr, chief of staff at the city of Fayetteville. Northwest Arkansas doesn't have a regional storm water management utility or anything that could be established as a funding arm and there is no funding stream other than the general sales tax, Marr said.
"I think the challenge is the funding because no one's general fund can handle the kind of capital requirement needed to reduce it immediately," Marr said. "We have identified $13 to $15 million worth of drainage improvements that could be done, that's two years of our CIP, a hundred percent of it. There has to be a funding solution developed."
Marr said another obstacle is that residents don't take kindly to their city officials or mayors spending their tax dollars on projects outside the city limits.
"They're all going to get un-elected," Marr said. "It's come up, whether it's been an arts center, whether it's been a transportation solution, a drainage solution, they're fine spending the money in their city limits but how do they explain to their citizens, even though it might be a regional problem, why they should use their money outside their limits when they've got all these issues in their own city limits to deal with."
A regional approach may be the only way help smaller cities, with their equally smaller budgets to get on board.
"At the end of the day, if the money's not there, the smaller cities can't do it." said Al Videtto, with the city of Lincoln.
Gary Blackburn, Garfield mayor, said the reality is his town would need outside help to participate.
"Garfield's 502 and we've got a backhoe and tractor," Blackburn said. "We couldn't hardly get anything done if it weren't for intergovernmental work with Benton County."
Morrow suggested developers could be charged fee a or a surcharge could be added to water bills to help pay for drainage improvements.
Videtto said rural water is already expensive.
"West Washington County has some of the highest poverty rates in the state," Videtto said. "We've got to remember when we're doing this there are people who are barely feeding themselves and if we put a high fee on their water then we might create more problems in other areas for them."
Many rural residents use also wells rather than buying their water, Videtto said.
Whatever the group ultimately comes up with needs to be applied uniformly by every entity to be effective and to make sure no one is put at an economic disadvantage, several members said.
Videtto and others said there's stiff regional competition to attract new businesses and jobs. Stricter development requirements typically drive up the costs of locating a new business and if it's cheaper in the next town over, a business may choose to go there instead.
"I think there is a real economic development reality to that and people use it against you to say you're over-regulating, you're creating more fees, we're going to go to XY community and not develop in yours, it becomes very difficult politically," Marr said. "The reality of it is you have to balance that with knowing other places don't have that and you're competing with them."
Maginot said she was pleased with the turnout and the amount of interest shown by the representatives at the meeting.
"There's at least some will there, there's at least a problem, we all agree on that," Maginot said. "So there's gotta be some kind of way to go forward whether it's an idea we can shoot for the stars or try to find out some smaller ways and smaller avenues as starting points."
The group wants to look at what scope of work the U.S. Army Corps of Engineers will allow to be done in streams and what can be done when problems, such as blockages, arise on private property.
"It turns into a very complicated issue, you've opened up a can of worms there with who owns it and who regulates it," Morrow said.
Several other ideas thrown out Wednesday, included public education campaigns, model ordinances cities could adopt, a regional utility or authority to deal with the issue, a master plan for Benton and Washington counties and a simple memorandum of understanding each entity in the region could execute. The group is expected continue meeting regularly.
"It would become a binding agreement. It may just be we all agree to study certain things," Morrow said. "I mean it takes away the issue of who's the first person in the water, the first one to get shot."
General News on 07/05/2017