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I I I I I I I I I I I I I I I I I I I Mr. Ben Urbonas. P.E. Page Two Mr. Ben Urbonas. P.E. Page Three A-2 3. This large basin includes property lying within Jefferson and Adams Counties and the cities of Golden. Wheatridge and Arvada. The potential impact of actions. or lack of actions. by one com- munity or another is significant. Each community has its own flood- plain regulation. How it chooses to administer that regulation can impact its own people and industries, as well as those people and industries downstream. And, I would add. direct or channel flood waters where they would not otherwise have gone in such to a location a quantity. 4. Because of the 1-76 development. a lOO-year flood chan- nelization program has been designed by the Colorado State Highway Department. The Report by Wright-McLaughlin points out very well the potential problem that such channelization may bring about if ~reater than 100-year floods occur (e.g.. a Big Thompson). Although it is undoubtedly too late to stop the 1-76 within-the-floodplain alignment, the District may wish to bring this problem as set forth in the Report (IV-17) to the attention of whoever at the State level is involved in flood hazard identification and designation. Although the State Highway Department has the right to condemn land wherever it chooses. just as local water and sanitation districts may place treatment plants wherever they wish, including floodplains this subject is worthy of some further legislative consideratio~. It . is one thing for local government to identify the flood hazard area and try to re~ulate that area; it appears to be something else when i~ ~omes to keeping another goyernment out of the floodplain (par- t1.cu1arly when that government 8 "improvement" attracts people and industries to the very ~dge of the lOO-year channel). There are three Colorado cases, City and County of Denver v. Talarico, 99 Colo. 178, 61 P.2d I (1936); City and County of Denver v. Strafacia, llO Colo. 114, 129 P.2d 674 (1942); and City and County of Denver v. Pilo, l02 Colo. 326, 79 P.2d 270 (l938), de~ling with a defect in a dike constructed by the City and County of Denver along the South Platte River pursuant to the City's authority under statute to maintain the channel of the river. A large flood occurred on a weekend when the City had been replacing a drainpipe and left the work uncompleted at the close of one week which caused damage to several different claimants. The basic holding of the Court in all three cases was that liability did not attach merely because t~e dike along the river was washed out. The principal considera- tion was whether the land would have suffered flood damage if the river had been left in its natural channel (i.e., if the dike had not been constructed). The Court said that the plaintiffs' vested right was to have their floodplain burden remain as nature had fixed it. However where it could be shown that the dike created a greater flood burden than would have existed had the stream been left without the dike, liability would attach to the builder of the dike. It should also be borne in mind that state law provides strict liability for defective dams, and in any instance where a dike could be likened to a dam, that liability would attach. PROBLEMS , To my knowledge, .the 1-76 plan is the first instance in which a berm has been used as a ~jor f10od~ontro1 device in the District (the Cherry Creek improvements incorporate a small berm at Monaco Parkway along Goldsmith Gulch. but that berm is insignificant in terms of total flood control). The District may desire to adopt criteria related to the use of major berms. The engineer at IV-l7 and subsequently points out Planning Problems (alluded to above). General Problems (such as channelization characteristics and berming characteristics), and then focuses in on Specific Problems. Before going to the Specific Problem areas and the proposed alternatives, a comment on berming is in order. The engineer points out at 1V-l9 that berming along a channel like Clear Creek has a major drawback. Twenty-seven Specific Problems, by Reaches I through IIIB, are outlined by the engineer from 1V-22 through 1V-26. The recommended alternatives are set forth in Section X. "Should a failure occur at any place along the berm during a large flood event. the conse- quences could be catastrophic. Flooding could be much worse than had the berm not been there. since a large volume of water may suddenly be released in a short period of time through a break in the berm." Reach I (from the South Platte to Huron Street) has been recommended for strict floodplain regulation so that the lOO-year flood hazard area is left open and free from development. If Adams County will administer its "Flood Control - Overlay Zone District" so as to preserve the identified floodplain. this Clear Creek out- let to the river will be preserved and this recommendation raises no legal problem.