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The Chamber of Couunerce has devoted several hours of study time to the various floodway regulations that are currently being considered. Through our study we have developed a position that we would like to take on the subject. First of all. we support the efforts to regulate use in the floodplain for the protection of life and property. Secondly, we do not advocate residential use of floodplains. We do support the concept of providing a large area within the floodplain for the passage I of the significant flows during a hundred year flood. However. where wide. flat floodplains occur on the outskirts of cities where the tra- ditional land use has been for industrial development. we urge that the designation of the floodway be such that unnecessarily large amounts of land not be removed from economic use. Only where industrial develop- ment would be subject to severe damage or damage others along the stream. only that land should be designated as a floodway. Unnecessarily restrictive floodway designations in the industrial areas could cause severe economic impact on communities. Industrial expansion most assur- edly would continue. but it would be done so in the places other than the floodplain. In other words. utilities, roads. everything else, would have to necessarily move to accommodate industrial growth. In some areas. very critical land use decisions can be made based on the interpretation of aerial mapping. which in itself is very far from precise. While aerial mapping of the large areas is probably the only economic tool available to municipalities and counties. its accuracy or lack of accuracy must be recognized. OUr recommendations are first in the floodway designations. We have seen designations of the 3 by 2 formula, the 1 foot plus the product of 3. the 2 foot plus the product of 7, 1.75 and 2 foot per second. 1 foot rise. the 6 ~nch rise. the 15 to 20% of the perimeter effect on the surface downstream. and several combinations of these. plus others that I p~obably failed to list. All of these designations have been deter- mined by responsible people in the field. Now out of this maze about the only one that we feel makes consistent sense is the one that is advocated by the Urban Drainage District. which is the 6 inch rise criteria. where equal encroachment on both sides of the stream or both sides of the floodplain don't increase the water surface elevation more than 6 inches. .This criteria we feel recognizes the responsibility of the developer to protect what he is constructing and also to protect others or not cause damage to others in the floodplain. It doesn't unduly increase velocities of flood flow and it doesn't take vast amounts of land out of economic use. It does provide adequate room for the passage of the major floods. And also it is probably one of the easiest to administer that we have. I would like to further recommend that a mechanism be included in your I regulation that recognizes the inherent inaccuracies of aerial mapping and provides a way for individuals to challenge floodplain or floodway lines on maps based on better field surveys. better engineering informa- tion. And that changes be made where justified based on the better data. Thank you. Mr. Stapleton: Thank you. very much. The next speaker is Mills Bunger. Mills. -57-