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Water Control Structures <br /> Permanent water control structures allow precise manipulation of water levels. The type of <br /> water control structure used will be determined during the wetland restoration survey and <br /> planning phase. It is anticipated that a flash-board riser structure will be used to regulate <br /> water behind two dike placements. A designed spillway might also be required on both <br /> dikes to insure positive water flow during flooding events. <br /> Seasonal Marsh Management <br /> The eastern section of Tracy Lake (Resource Map) will be intensively managed, at least in <br /> part. These areas will require controlled, seasonal flooding, and careful drawdown to <br /> foster wetland plant and invertebrate communities. Existing pumps will be utilized to <br /> deliver water during critical times of the year, such as early fall,during periods of drought <br /> to maintain or create wetland habitats,or at critical times for mosquito control. <br /> The proportion of open water to vegetation influences waterfowl species use (Fredrickson <br /> and Reid 1988). For example, northern pintails (Arras acuta) and snow geese prefer <br /> seasonal marshes with less than 35% plant cover, whereas mallards and gadwalls (Anas <br /> strerpera)prefer seasonal marshes with 40-60% plant cover. After 3-5 years, seasonal <br /> marshes are expected to exceed the 50% ratio of vegetation to open water. A combination <br /> of disking and/or burning may be required to maintain plant cover at the appropriate level <br /> of plant succession. <br /> Shorebirds prefer open early successional mud flat habitats. Shorebird habitat may be <br /> created by selected disking of shallow water areas prior to fall flood-up. Woody vegetation <br /> may become established in certain seasonal marsh habitats which may be detrimental to the <br /> Buckeye Ranch Resource Plan (November, 1993) <br /> 188 <br />