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CAST EST'IMA`TE To arrive at a detailed cost estimate, appropriate data for streams/rivers were collected and some broad assumptions were made. It is assumed that the project would be completed over a period of six years. To determine the DEM cost, a state map with the major watersheds, labeled by priority, was prepared (see page 7). The area of each major drainage basin was tabulated and the DEM cost was calculated. The task would also include building digital terrain models (DTM) from the DEM, which would require 120 ground elevation control points per county. The cost to develop a DEM and DTM would be $41 million. Information and technology (IT) needs, along with staffing, are projected to cost $5 million and $7 million respectively. The floodplain mapping cost assumed the cost to complete hydrologic studies (determination of flow frequencies) ofsub-watersheds for major tributaries, and the cost for hydraulic analyses. These costs were determined county- by-county from FEMA flood insurance studies and from USGS quadrangle maps. The total cost to conduct hydrologic and hydraulic studies and to produce digital flood insurance rate maps (DFIRMs) is approximately $27 million. Funding Scenario (millions of dollars: Minnesota Fiscal year 2004 2005 2006 2007 200$ - ---- Minnesota Legislature $13 $14 $23 (Appropriation to DNR) FEMA $10 $7 $10 MnDOT $0.5 $0.5 $0.5 $0.5 $1 (Ground elevation quality control*) Total by year $23.5 $7.5 $24.5 $0.5 $24 T'atal ...............................................................................................$80 rniiiion * in-kind services The benefits would be significant for investing in a statewide high-resolution DEM and floodplain mapping program. We have good quantitative data, based on work in North Carolina, indicating abenefit-cost ratio of 3.5:1 on flooding alone. Details of flood experiences in Minnesota illustrate how these benefits could be realized at home.