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Chun S.N.,3310 El Camino Avenue | Cocherell S.A.,University of California at Davis | Cocherell D.E.,University of California at Davis | Miranda J.B.,University of California at Davis | And 5 more authors.
Environmental Biology of Fishes

We studied whether juvenile fishes were able to maintain swimming speed and position during simulated river pulsed flows in a laboratory flume. We used a glass flume (15.24 × 0.6 m) with river-rock substrate to determine the longitudinal displacement, movement distances and frequencies, velocity selection, and substrate use of juvenile (SL range: 6.1 ± 0.2 cm) hardhead Mylopharodon conocephalus (n = 13), rainbow trout Oncorhynchus mykiss (n = 11), and Sacramento sucker Catostomus occidentalis (n = 12) during a 100-min flow pulse, as velocity changed from slow to medium, fast, medium, and slow. Fish were capable of maintaining swimming speed and position up to the maximum flume velocity of 0.46 m·s-1, except for one hardhead that impinged on the rear fish screen. Fish swam faster in the flume during the medium and fast intervals than the slow intervals, but fish speeds were similar among the medium and faster intervals, when some fish took cover behind the rock substrate. In comparison with a Brett-type swim-tunnel, fish showed less increase in mean swimming speed as the flume velocity increased. Fish in the flume were able to use the rock substrate as hydraulic cover, decreasing the encountered water velocity, and, presumably, conserving energy. © 2010 The Author(s). Source

Ohara N.,University of Wyoming | Kavvas M.L.,University of California at Davis | Chen Z.Q.,3310 El Camino Avenue | Liang L.,3310 El Camino Avenue | And 3 more authors.
Hydrological Processes

The restoration of meadowland using the pond and plug technique of gully elimination was performed in a 9-mile segment along Last Chance Creek, Feather River Basin, California, in order to rehabilitate floodplain functions such as mitigating floods, retaining groundwater, and reducing sediment yield associated with bank erosion and to significantly alter the hydrologic regime. However, because the atmospheric and hydrological conditions have evolved over the restoration period, it was difficult to obtain a comprehensible evaluation of the impact of restoration activities by means of field measurements. In this paper, a new use of physically based models for environmental assessment is described. The atmospheric conditions over the sparsely gauged Last Chance Creek watershed (which does not have any precipitation or weather stations) during the combined historical critical dry and wet period (1982-1993) were reconstructed over the whole watershed using the atmospheric fifth-generation mesoscale model driven with the US National Center for Atmospheric Research and US National Center for Environmental Prediction reanalysis data. Using the downscaled atmospheric data as its input, the watershed environmental hydrology (WEHY) model was applied to this watershed. All physical parameters of the WEHY model were derived from the existing geographic information system and satellite-driven data sets. By comparing the prerestoration and postrestoration simulation results under the identical atmospheric conditions, a more complete environmental assessment of the restoration project was made. Model results indicate that the flood peak may be reduced by 10-20% during the wet year and the baseflow may be enhanced by 10-20% during the following dry seasons (summer to fall) in the postrestoration condition. The model results also showed that the hydrologic impact of the land management associated with the restoration mitigates bank erosion and sediment discharge during winter storm events. © 2013 John Wiley & Sons, Ltd. Source

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