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. . . the 1993 flood. No flow measurements were made in any of these floods, so no frequeney estimates ean be made. Previous Studies and Proieets Two floodplain information doeuments have been mentioned in this report. In May 1986 Engineering Professionals, Ine. prepared a report entitled Town of Otis Master Drainage and Flood Study. The report determined flood flows in Otis, delineated lO-year and 100-year floodplain boundaries based on those flows, and proposed eoneeptual flood eontrol elements to address the problems that were identified. In January 1988 Norton, Underwood & Lamb designed flood eontrol and storm drainage improvements, as shown on a map entitled Project Layout, Drainage and Floodplain Improvements. Those improvements were subsequently eonstrueted to improve eonditions north of the erossing of the Southwest Drainage under the Burlington Northern Railroad. While additional improvements were designed for the south side of Otis at the same time, those improvements were not eonstrueted. The preparation of the Master Drainage and Flood Study in 1986 began the town's efforts to address some of its flooding and storm drainage problems through eonstruetion of struetural improvements. In the northeastern portion of Otis a flood eontrol projeet, shown in detail on the Norton, Underwood & Lamb map, was eompleted in 1988. That project provided 100-year flood eapaeity for the Southwest Drainage immediately downstream of the railroad erossing all the way to the northeastern eorporate limit of Otis. The projeet included channelization and the replaeement of eulverts under Highway 34. In addition, storm drainage improvements whieh tie into the flood eontrol ehannel greatly redueed some localized ponding problems in the northern part of Otis and in the northwestern part of Otis, near the high sehool. A swale was eonstrueted along a portion of the Northern Drainage to reduee the flood risk along the northern edge of Otis as a part of this projeet. No ehanges were made at the railroad erossing exeept for some minor ehanges at the outlet. The town has eontinued to attempt to reduee flooding and drainage problems in the area upstream of the railroad erossing. Beeause the railroad erossing struetures are sueh a severe eonstraint to large flows, any improvements that do not inerease the capaeity under the railroad can only improve eonditions up to approximately a 7 -year frequeney. At the time of this report the town and its engineer, MeLaughlin Water Engineers, was working on such a project, with a design frequency of approximately a 7-year flow. A channel with some conerete street crossing structures will be eonstrueted between two north-south streets, Washington and Vine. The projeet will not alter the drainageway downstream of Vine, toward the railroad erossing, and it will not alter the drainageway upstream of Washington, to the southwest. It will eontrol floods up to a 7 -year magnitude, and it will greatly aeeelerate the time for draining the "lake" that forms on the south side during bigger floods. No measurable ehanges to the 100-year floodplain are expeeted as a result of this projeet. The project should be eomplete in time for the flood season of2000. 4