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Hydrologic budgets for depressional wetlands require estimates of runoff from watersheds. In the Southern High Plains, where there is little elevation relief, ground surveys provide accurate watershed estimates but are time-consuming and costly. Estimates can be derived at lower cost from DEMs (Digital Elevation Models) and topographical maps, but data resolution and interpretation introduces errors. Other computational methods provide alternatives for estimating watershed area. Two computational methods based on longitudinal distances and elevations are described; minimal distance method and weighted minimal distance method. Twenty playas were ground surveyed to obtain baseline estimates of watershed area. Watershed...
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More than 25,000 playa wetlands are embedded in the Southern High Plains (SHP), USA. The SHP is one of the most intensively cultivated areas in the world and, as a result, the function of playas has been altered by deposition of eroded sediments. We monitored water levels in 33 playas in summer 2003 to examine the influence of land use (cropland vs. native grassland) and playa characteristics (playa area, watershed size, starting water level, volume loss, sediment depth, percent playa vegetation cover, and soil texture zone) on water loss rate and hydroperiod (consecutive days a playa held measurable surface water). Multiple regression models (selected using Akaike’s Information Criterion) indicated that land use,...
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1. Hydroperiod, wetland size and land use of watersheds surrounding wetlands have important individual influences on plant communities in wetlands. Our objectives were to determine the effect and relative importance of local and landscape factors on plant species richness, diversity and composition of different functional groups (i.e. total, wetland-dependent, perennial, annual and exotic species) in recently inundated playa wetlands.2. We surveyed plant communities in 80 wet playas in the Southern High Plains, USA, and measured local factors: water depth, playa volume loss, sediment depth and playa area. We included landscape variables within 3 km: number of playas, edge density, percentage urban area and percentage...
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Playa wetlands in the Southern High Plains provide services such as stormwater storage, groundwater recharge, and biodiversity provisioning. However, watershed erosion has negatively impacted these services. Previously, we demonstrated that water loss rate was influenced by land use variables such as watershed cultivation (tilled index) and playa volume loss (hydric soil defined wetland volume). Because non-anthropogenic water loss in playas is limited to evaporation, transpiration, and infiltration processes, our objective was to determine the impact of wetland vegetation characteristics and land use variables on water loss rate in playa wetlands. We recorded water levels of 70 playas through the summers of 2003...
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