01-24-2000 Council Work Session - Laserfiche WebLink

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I I I i'. r i. p» i • I »>* i I i« p*\ M >♦ i K M II I! b & SIIORELAND. FLOOD PLAIN ANH STORM WATER CONSIDERATION S SURFACE WATER MANAGEMENT Orono’s many miles of shoreline are especially sensitive to misuse or overdevelopment. As the interface between land and water, the shoreline is ever changing. Shorelines are subject to continual erosion by wave action, ice buildup or unstable soil conditions. Droughts dry out vegetation and heavy rains or snow melt cause land slippage. On top of these natural pressures, man is drawn to the lake and the shoreline often becomes his battleground with nature. Lake access often means active use and construction of buildings and structures causing unnatural soil loadings, vegetation removal, and land alteration. Exposed soil becomes more subject to erosion and man-made hardcover increases direct runoff quantity and speed. Power boats increase wave action and, more damaging, stir up the lake bottom causing release of nutrients and increased turbidity. The impact, of course, is a degradation of water quality, impaired lake access and a change in the natural aesthetics which drew people to the shore in the first place. Legal considerations become entangled when lot descriptions conflict or become inconsistent due to changing water levels or shoreline locations. Therefore, planning considerations must recognize the desirability of human interaction with the lake while at the same time providing for protection of nature’s sensitively balanced shoreline ecology. Flood protection and floodplain management arc extremely important to a community' as closely associated with water resources as is Orono. Orono has no river system and therefore has no potential for swift, destructive floods in the typical sense. But general highwater conditions have the potential of affecting many properties by slowly rising water levels, shoreline destruction and high water tables. Most critical are those residences built on low-lying peninsulas such as Baldur Park, where a combination of high water levels and wave action caused by powerboats or high winds mav cause severe shoreline erosion. In addition. Hooding of upstream marshes may tend to cause localized backups or drainageway overloads. Orono has participated in the National Flood Insurance Program and has therein undertaken detailed studies of fiood-prone areas. Very few structures are actually affected but care is necessaiy to ensure no luture flood plain encroachment and no future loss of natural ponding areas which would result in higher water levels elsewhere. The general trend seems to be potential for increasing high water problems as urbanization spreads in other areas of the watershed thereby reducing natural ground water assimilative capacity, eliminating ponding areas and increasing CMP3A- 12 I