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In the past two decades, major flood events have occurred on the lower Colorado River, a dramatic shift from the low flows and moderate floods associated with prior decades of river regulation. This study uses repeat aerial photography and Geographic Information System analysis to examine the planform channel response of the upper Colorado River delta (limitrophe reach) to this recently altered hydrology. Results indicate that channel contraction has been the dominant planform process in recent decades, but periodic floods resulted in channel expansion (1981–1988; 1997–2000) or likely reduced the channel contraction measured between successive aerial photographs (1976–1981; 1988–1994). Sinuosity adjustments...
Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk (Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood (Populus spp.) and willow (Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately...
Floodplain plant-herbivore-hydroperiod interactions have received little attention despite their potential as determinants of floodplain structure and functioning. We used five types of exclosures to differentially exclude small-, medium-, and large-sized mammals from accessing Fremont cottonwood (Populus deltoides Marshall subsp. wizlizenii (Watson) Eckenwalder) seedlings and saplings growing naturally on four landform types at an alluvial reach on each of two rivers, the Green and Yampa, in Colorado and Utah. The two study reaches differed primarily as a result of flow regulation on the Green River, which began in 1962. Landforms were a rarely flooded portion of the alluvial plain, geomorphically active slow-...
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These data were compiled from pitfall traps deployed at three sites, along a 25 kilometers (km) stretch of the Colorado River, immediately downstream of Glen Canyon Dam, in Glen Canyon National Recreation Area. Each site had both pre and post-dam riparian habitats present. The purpose of the sampling was to determine if arthropod abundance, diversity and feeding guilds differed between habitats. Sampling for ground-dwelling arthropods using pitfall traps occurred continuously between June 17 and September 9, 2009. The site numbering proceeds from Glen Canyon Dam to Lees Ferry. Transects were composed of 10 pitfall traps approximately 10 meters apart in a line parallel with the river in both zones (Upper riparian...
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This data is a compilation of fishery monitoring data collected by state agencies over several decades in tailwaters downriver of dams in Colorado, Utah, Montana, Wyoming, Idaho, New Mexico, Arizona, California, and Oregon. Specifically, the data contained herein is summary data used in four generalized linear mixed models that were developed to assess the biological and hydrologic factors that influence rainbow and brown trout recruitment and adult size in tailwaters across the western United States.
Categories: Data; Types: Citation; Tags: Anderson Ranch dam, Beaverhead River, Bighorn River, Blue River, Boysen dam, All tags...
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* 1 The structure and functioning of riverine ecosystems is dependent upon regional setting and the interplay of hydrologic regime and geomorphologic processes. We used a retrospective analysis to study recruitment along broad, alluvial valley segments (parks) and canyon segments of the unregulated Yampa River and the regulated Green River in the upper Colorado River basin, USA. We precisely aged 811 individuals of Populus deltoides ssp. wislizenii (native) and Tamarix ramosissima (exotic) from 182 wooded patches and determined the elevation and character of the germination surface for each. We used logistic regression to relate recruitment events (presence or absence of cohort) to five flow and two weather parameters....
Growth and survival of Colorado squawfish, Ptychocheilus lucius, larvae under fluctuating 18, 22, and 26 degrees C (5 degrees C diel fluctuations) and constant 18, 22, 26 degrees C, and 30 degrees C temperature conditions and ration size corresponding to 12.5, 28, 64,142, 320 brine shrimp nauplii fish(-1) day(-1) was determined from laboratory experiments. Growth was optimal at 31 degrees C and high at temperatures of 26 degrees C to 30 degrees C, at the highest food abundance. Lowest growth was under lowest food rations and highest temperatures. Growth of Colorado squawfish larvae declined substantially at temperatures < 22 degrees C. Neither growth nor survival was significantly different between fluctuating or...


    map background search result map search result map Multiple pathways for woody plant establishment on floodplains at local to regional scales Flow management and fish density regulate salmonid recruitment and adult size in tailwaters across western North America—Data Ground-dwelling arthropod composition, Colorado River, Grand Canyon, 2009—Data Ground-dwelling arthropod composition, Colorado River, Grand Canyon, 2009—Data Multiple pathways for woody plant establishment on floodplains at local to regional scales Flow management and fish density regulate salmonid recruitment and adult size in tailwaters across western North America—Data