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OOO~10 WET MEADOWS Wet meadows are one type of wetland identified by Mitsch and GOsselink (1986). Wet meadows along the Platte River Valley are subirrigated by an unconfined, shallow, aquifer. Their dynamic, ecological complexity in combination with their juxtaposition and diversity contribute to the overall value of wetland complexes in the Platte River Valley (Figure C1). Ground water levels in the general area along the Platte River closely respond to changes in river stage (Hurr 1983), and the water table may occasionally or frequently be at or near the surface (Wesche et al. 1989). As a result, continua of organisms that occur along slight vertical (elevation) gradients attributable to the micro-topography of swales, terraces, and channel scrolls in the Valley. Changes in river hydrology likely have a direct influence on the extent and the type of wetlands, and in turn the functional biological values derived from them. Change in anyone of several variables of the hydro-period fluctuations including timing, magnitude, or duration of flow would likely result in change in aerial extent of wetlands and in wetland type and ecological function (Kusler 1987, Zimmerman 1987, Weller 1987, Winchester et al. 1987). Episodic, high flow events are probably the most important determinant of wetland type and function, and should be the primary consideration a flow regime targeted for the wet meadow resource. Frequency, duration, and seasonality of hydro-period peak flows are primary determinants of wetland structure and function (Mitch and Gosselink 1986, Hill et al. 1991). In addition, the dynamics (or stochasticity) of timing, frequency, and duration are essential to ecological functions and dynamics of wetlands (Currier 1988, Fredrickson 1991). Base flow during low flow seasons may also influence wetland productivity. organisms within the wet meadow communities have evolved ecologically, and adapted strategies and life-cycles that are suited to particular hydrologic conditions. Conceptually, the best management strategy for maintaining wet meadow as a biologically functional component of the Platte River ecosystem would be to protect existing peak flow pulses and to recover flow pulses of hydro-period fluctuations in some semblance of their natural pattern. Early discharge records would reveal the pattern toward which recovery should be directed. Gaging records at Duncan, 1929- 1938, were the earliest continuous records of spring flows immediately obtainable for this review (Figure C2). The limitations of this data should be noted. The 1929-1938 period 13