115 research outputs found
Ecología social de la zona de San Juan.
Resumen en español.Resumen en inglés
Tracer study of mixing and transport in the Upper Hudson River with multiple dams
Abstract In October 2001, ca. 0.2 mol of SF 6 was injected into the upper Hudson River, a modified natural channel with multiple dams, at Ft. Edward, NY. The tracer was monitored for 7 days as it moved ca. 50 km downriver. The longitudinal evolution of the tracer distribution was used to estimate 1-D advection (9.0 ± 0.2 km d -1 ) and dispersion (17.3 ± 4.0 m 2 s -1 ) along the river axis. Comparison of these results to tracer studies on channels without dams suggests that dams reduce longitudinal dispersion below the value expected in a natural channel with the same discharge. SF 6 loss through air-water gas exchange along the river and at two dams (10.7 m combined height) was estimated by observing decay in peak concentration. Losses at dams (approximately 50% per dam) were dominant. The estimated gas exchange at dams was compared to a simple model adapted from those available in the literature. Small amounts of tracer were trapped in a canal segment (ca. 5 km long) that parallels the river, where advection and dispersion were sharply reduced. Caplow, Schlosser, and Ho
- …