Dakota County gets updated look at flood risk

A decade-long national response to catastrophic flooding in the mid-1990s finally reaches the south metro area tonight when federal officials unveil for Dakota County residents the results of new and more sophisticated mapping they've done to determine who's most at risk.

The billion-dollar effort to update flood-risk maps -- many of which dated from the '70s or '80s -- is gradually spreading across the country. It is expected to reach Scott County within a month or two, with new maps being made public there, said Ceil Strauss, floodplain hydrologist for the Minnesota Department of Natural Resources.

The results will give homeowners a clearer sense of their susceptibility to flooding, but the federal effort is also aimed at local governments, helping them understand the consequences of allowing development in flood plains.

"There still are big levee projects being done," Strauss said, "but the emphasis has shifted toward keeping people out of the floodplains in the first place -- or if they do build in a fringe area, building in such a way that the lower levels are high enough to prevent damage if there is a flood."

Dakota County has reached the stage in which property owners can examine and potentially challenge the maps, based on their own knowledge of the terrain, before the maps are finalized and start affecting zoning and the need for flood insurance.

Folks attending tonight's open house in Dakota County, Strauss said, will find that the effect of the new maps is not as dramatic as it was in Washington County, for instance, where maps unveiled last winter revealed high flood danger for many homes that had not been previously mapped at all.

In parts of Dakota County, new and more fine-grained elevation maps actually shrunk the area considered most at risk.

Dakota County cities tend to have "pretty well-developed flood maps already," said Jim Skelly, spokesman for the city of Burnsville, "but townships do not -- and now will have that. It's a necessary and beneficial thing for property owners and insurance companies, to make sure they have accurate information."

Even in cities, he added, the information is often old and not nearly as user-friendly as the new maps, which can be viewed online and which show flood danger superimposed upon aerial photos so that people can see whether their homes are considered at risk.

Generally speaking, experts say, Scott County is more at risk of flooding than Dakota. On Tuesday, in fact, the Scott County board approved a $48,000 expenditure to help study flood risks in Jordan, where much of the original town site is constantly threatened by flooding.

The maps aren't the final word on flood risk, Strauss cautioned. "One thing we do try to remind people is that just because you're not shown as 'high risk' doesn't mean you're not in area that could get flooded," she said. "This effort doesn't map smaller streams or stormwater ponds."

David Peterson • 952-882-9023