Skip to main content
Advanced Search

Filters: Tags: flow regulation (X)

4 results (6ms)   

View Results as: JSON ATOM CSV
We compared beaver (Castor canadensis) foraging patterns on Fremont cottonwood (Populus deltoides subsp. wislizenii) saplings and the probability of saplings being cut on a 10 km reach of the flow-regulated Green River and a 8.6 km reach of the free-flowing Yampa River in northwestern Colorado. We measured the abundance and density of cottonwood on each reach and followed the fates of individually marked saplings in three patches of cottonwood on the Yampa River and two patches on the Green River. Two natural floods on the Yampa River and one controlled flood on the Green River between May 1998 and November 1999 allowed us to assess the effect of flooding on beaver herbivory. Independent of beaver herbivory, flow...
Tributaries may either ameliorate or exacerbate the geomorphic and ecologic impacts of flow regulation by altering the flux of water and sediment into the flow-regulated mainstem. To capture the effects of tributary influences on a flow regulated river, long-term discharge and cross-sectional data are used to assess the geomorphic and hydrologic impacts of impoundment. In addition, the use of the short-lived cosmogenic radioisotope 7Be (half-life 53·4 days) to link sediment transport dynamics to benthic macroinvertebrate community structure is evaluated. It is found that the 7Be activity of transitional bed load sediment is highly seasonal and reflects both variations in activity of sediment sources and limited...
thumbnail
The Gunnison River in the Black Canyon of the Gunnison National Park (BCNP) near Montrose, Colorado is a mixed gravel and bedrock river with ephemeral side tributaries. Flow rates are controlled immediately upstream by a diversion tunnel and three reservoirs. The management of the hydraulic control structures has decreased low-frequency, high-stage flows, which are the dominant geomorphic force in bedrock channel systems. We developed a simple model to estimate the extent of sediment mobilization at a given flow in the BCNP and to evaluate changes in the extent and frequency of sediment mobilization for flow regimes before and after flow regulation in 1966. Our methodology provides a screening process for identifying...
Riparian plant communities are shaped by gradients of disturbance intensity and frequency and resource availability. Reservoir operation can alter the composition and abundance of riparian vegetation by changing the flood regime and by trapping fine sediments and associated nutrients within the reservoir system. We examined differences in herbaceous species richness, abundance and composition in Populus-Salix stands along an unregulated and regulated reach of a river in semi-arid Arizona, contrasted flood inundation frequency and edaphic conditions (soil moisture, nutrients and texture) between the reaches, and interpreted the vegetation differences in light of observed differences in environmental conditions. Flooding...
    map background search result map search result map Assessment of coarse sediment mobility in the Black Canyon of the Gunnison River, Colorado. Assessment of coarse sediment mobility in the Black Canyon of the Gunnison River, Colorado.