| OCR Text |
Show Alternative B: Collect baseline information on springs, seeps, and waterpockets ( preferred alternative) The baseline chemistry and hydrology of springs and seeps would be further documented through research and monitoring by NPS or other organizations and scientists. Study objectives would include chemical profiles to document aquifer origins and the current condition of spring water, and flow measurement to generate a basis for comparison against possible future disturbances. Spring flow along the Colorado River below Glen Canyon Dam would be measured periodically to detect any potentially significant changes in flow rate. This objective could be achieved cooperatively with the Bureau of Reclamation. The biology of springs, seeps, and waterpockets would be systematically studied to identify significant communities and the water resource features necessary to support them. Such studies would also improve impact evaluation efforts and the interpretation of park resources for the visitor. III. G. 3. Recommended course of action. Alternative B would result in additional information about significant park resources subject to diminution by developments involving minerals or range cattle. Without the background data base, improper assessment of adverse impacts to these backcountry water resources could occur. III. H. Water Resources of Riparian Ecosystems III. H. 1. Statement of the problem. Riparian ecosystems are water- dependent biotic communities that develop along the banks of rivers, streams, and lakes. They are of major significance as wildlife habitat, recreational sites, and sources of productivity. Riparian ecosystems in Glen Canyon National Recreation Area consist of 1) riverbank biotic communities in the numerous canyon tributaries to the lake and along the major rivers entering the area, 2) lakeshore plant communities, and 3) vegetation around springs and seeps. They support a diversity of fish, wildlife, and plants and provide cool, scenic recreational sites for the recreation area visitor. The riparian communities along the Colorado River below Glen Canyon Dam are the best known, having been studied extensively for nearly 20 years. These studies document the progress of ecosystem changes resulting from curtailed flooding. Changes include an expansion of tamarisk ( Tamarix ramosissima, an exotic species) and an accompanying increase in bird and insect abundance ( Carothers and Aitchison 1976). An intensive interagency study of this river reach is in progress to evaluate the potential effects of alternate water release schedules from the dam. 39 |
