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APPENDIX E EFIT.~a ~f ~E~ and Fi~®~PLA~tV ~'dAP~ A statewide high-resolution digital elevation model (DEM) would provide critical information to create current and accurate floodplain maps that would benefit Minnesota, but would also benefit other activities of government and the private sector. This appendix is intended to document the extent of those two beneflts.I The State of North Carolina has suffered from flooding, mostly due to hurricanes, and conducted an intensive benefit/cost study to estimate the value of having good floodplain maps. They concluded that "for every dollar spent on mapping, the payback is $3.50?" Part of the reason for this high ratio of benefit to cost is the relatively low cost of new LIDAR technology. Compared to traditional methods of collecting elevation data, LIDAR is 30-50 percent cheaper. North Carolina experiences annual flood damages of $56 million. Minnesota averaged a whopping $90 million annually in expenses reimbursed by state and federal agencies in the 1990's. Flooding in Minnesota during 1997 alone caused an estimated $1.5 billion in damages. The damages would have been worse were it not for the permanent flood control structures in place, the measures taken in advance of the floods and the emergency measures taken during the floods. Significant flood damages were inflicted on the Cities of East Grand Forks, Ada and Breckenridge, but over 40 communities were spared by preventive actions. Better floodplain maps would have reduced that damage even further by helping communities manage their floodplains before the floods and by directing mitigation efforts during the events. Local governments currently are trying to make decisions about flood events, decisions that could be much easier with current and accurate floodplain maps. These decisions could save lives and money, but officials are flying blind. For example, the City of East Grand Forks gets roughly 300 building permit applications per year and is struggling with old floodplain maps and less than optimal elevation data as it tries to make decisions about whether or not to approve them. Meanwhile, the city gets over 500 calls a year from banks and others about whether buildings are in or out of the floodplain. In the Roseau County, which recently suffered flood damage to some 1500 homes, local officials are trying to reduce future damage by planning projects that include levees, bypass channels, and upstream divisions -projects that can be planned well only with better floodplain and DEM data. ' A number of people provided key information reported in this appendix. They include: Ann Banitt, Hydraulic Engineer, US Army Corps of Engineers; Jay Bell, Professor of Soil, Water and Climate, University of Minnesota; Jeff Grosso, Surveyor, City of Saint Paul; Tom Lutgen, Floodplain Program Hydrologist, Waters Division, Minnesota Department of Natural Resources; Larry Nybeck, Deputy Director/County Surveyor, Survey and Land Management Division, Washington County; and Lisa Sayler, Hydraulics Automation Engineer, Minnesota Department of Transportation. - Smith, Brandon R. 2002. Floodplain Fliers: North Carolina's Massive LIDAR Project, GeoSpatial Solcctions, February, 28-33.