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ND Risk Assessment Mapservice offers flood risk data

New map tool makes data available to all

Submitted Photo A sample of the North Dakota Risk Assessment Mapservice shows a portion of southwest Minot, with a 1% annual flood risk identified in blue.

A new online mapping tool means convenient and free access to flood risk information for North Dakota residents and communities.

North Dakota Risk Assessment Mapservice and Base Level Engineering is the result of two years of work conducted through the State Water Commission. The online tool launched this past October.

Communities can benefit from the map when making decisions about construction of public projects, route planning or flood risk reduction, said Aaron Carranza, director of the regulatory division at the State Water Commission.

“The NDRAM platform provides information that, in some areas, never existed on a large scale, as far as risk assessment or an understanding of what the level of risk was,” Carranza said. “So I think it really is a new world we’re entering in with these community leaders – to have information at their fingertips to drive a lot of these conversations and come in very well prepared and able to attack the risk, eyes wide open.”

Having the assessment information is valuable to residents, too, particularly property owners looking to develop their land, said Laura Horner, state RiskMAP coordinator.

“We frequently hear from homeowners that come to us and say, ‘Had I known, I would have done this differently, I would have built differently, I would have picked a different lot’ – whatever the situation may be in their case,” she said.

NDRAM offers a user-friendly interface for the general public interested in learning the flood risk in their areas. Residents can find their properties using zip codes and house numbers based on their 911 addresses.

The website address is https://ndram.swc.nd.gov.

Horner said the project developed after the Federal Emergency Management Agency’s Region 8 office in Denver approached the state in early 2017 to ask about partnering on a pilot project.

North Dakota had statewide geographic information obtained using LIDAR, a remote sensing method using pulsed laser light. FEMA was interested in using the existing data to establish a floodplain assessment of the entire state and better identify risk in areas that, historically, don’t warrant a full-fledged FEMA risk map project, Horner said.

FEMA sought to use a base-level engineering approach, employing existing LIDAR data in a software program capable of automating a large rainfall event. The map tool displays multiple-sized flood events, showing how flooding might occur during a 500-year event (0.2% annual risk) or an event as frequent as every 10 years (10% annual risk).

The project required extensive research and public outreach, engaging more than 500 community stakeholders in 86 in-person meetings to help verify data. It involved a $33 million public investment.

Prior to the map development, residents not in the National Flood Insurance Program would have to hire a private consulting firm to conduct a hydrology and hydraulics analysis to obtain base engineering information for their properties, Carranza said. Without that, information would be limited to word-of-mouth, historic reference, he said.

“It’s really meant to help inform and to allow an individual to go into a situation with the information needed to understand their risk,” Horner said. For example, she said, someone who buys a lot might discover on the NDRAM system that the lot will incur nuisance ponding in a heavy rainfall event. That owner then would want to bring in extra fill before building.

By helping residents understand their flood risk, the hope is the map tool will alert homeowners who aren’t required to carry flood insurance to the flood potential and the possible need to purchase that insurance, she said.

More than 17% of the state has been identified through base level engineering as being at high risk, considered to be a 1% chance of an annual flood event, or once in 100 years. The National Flood Insurance Program identifies 2.5% of the state as having a high flood risk.

The advantage of NDRAM is it captures areas that FEMA does not, such smaller ponding areas that might only affect a few lots, Horner said. It captures rural areas and communities that FEMA hasn’t been mapping.

“Right now, we have all of our ponds are very full within North Dakota, just due to the fact the ground is so saturated and we have an abundance of water. Those small, little nuisance-type flooding hazards aren’t normally captured on a FEMA risk map product. That’s beyond the scope of what FEMA looks for, but if you look at the NDRAM system, you will see those depressions. You will find very, very small areas that tend to be more of a large puddle or some of that localized nuisance flooding,” Horner said.

Ward County is included in the map tool, but there also is an ongoing FEMA mapping project along the Souris River and its tributaries in Minot, Burlington and Sawyer to establish flood risk in greater detail. Those revised, preliminary flood maps are available through the FEMA maps service center at https://msc.fema/gov.

“Those are still your best available products, and the products that you should work with the local flood plain administrator on as far as options and some of your future plans. If you happen to be impacted by that floodplain, it also might be a good opportunity to have a good conversation with your insurance agent if that (flood insurance) is something that you choose to have on hand prior to those maps moving forward,” Horner said.

One benefit of NDRAM for Ward County is the application to areas outside of the FEMA map area. In those cases, NDRAM might be the only assessment tool available to gauge risk and help in decision making, Horner said.

“Our state is very wet, putting a lot of stress on the potential flood conditions that we could see this spring. This last snowstorm did not help much of the state of North Dakota,” she added, “and it’s why we are continuing to amp up and try to communicate that aspect of risk and preparedness as we get through the rest of our winter and into our spring months.”

Response to NDRAM has been positive, especially given the interest in the state’s current moisture situation, she added.

“All in all, I think the the information, and the fact that we have hosted it, is being very, very well received. I think the biggest question that we’re kind of getting right now is, ‘Now, what do we do with the data?’ What kind of decisions, what kind of next steps, do we need to make from a homeowner’s point of view, right up to the community’s point of view?” she said. “Now that we have the data, how do we utilize it in helping inform our decision making?”

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