Research

ASSESSING HYDRAULICS and FISH BEHAVIOR and SWIMMING PERFORMANCE NEAR UNSCREENED DIVERSIONS on the SACRAMENTO RIVER: LARGE FLUME SIMULATIONS

The study addresses critical questions regarding unscreened diversions and assesses their threats to juvenile Chinook salmon. The work found that both the designed louver-array box and perforated cylinder fish-guidance devices reduced fish entrainment risk during pipe passage by roughly 99%. Under control conditions, 50% of out-migrating salmon are estimated to be entrained after encountering 5 to 7 unscreened water diversions under the conditions tested in these experiments. With the louver array box or the perforated cylinder attached to the pipe, it would take well over 350 encounters with water diversions before we expect to lose 50% of fish to entrainment mortality. These devices offer a promising, low-cost method of reducing fish entrainment without reducing water-intake rates, which may provide an alternative to positive barrier screens at small-sized water diversions.

SEDIMENT TRANSPORT and DEPOSITION TESTS

Laboratory experiments were performed in order to understand the sediment transport and deposition processes in the Cache Creek Settling Basin (CCSB). Sediment, brought from the (CCSB) was used in two sets of tests, planned and performed in order to understand the sediment transport and deposition processes. The first set of tests were performed to mimic the combined sediment transport and deposition processes. The second set of tests were performed to understand the settling process and the ensemble behavior of settling velocities. The experimental data were later utilized to evaluate the performance of computer simulations.

2-D UNSTEADY FLOW and SEDIMENT TRANSPORT MODELING

Evaluation of settling basin trap efficiency with respect to current and future settling basin design, through 2-dimentional unsteady flow and sediment transport modeling.  Calibration and validation utilizing: field measurements of flow, velocity, water depth and suspended sediment in Cache Creek and the CCSB; high-resolution digital elevation data of the Basin; and experimental laboratory study results.

STUDY of the ROUGHNESS CHARACTERISTICS of NATIVE PLANT SPECIES in CALIFORNIA FLOODPLAIN WETLANDS

Major objectives of this study are to: determine the hydraulic roughness (Manning’s n) associated with sandbar willow, mule fat, blackberry and wild rose riparian plant species under various flow conditions (from low to high flows) in comparison with bare soil roughness conditions that may be present on the floodplains in river reaches where these plants occur; determine soil erosion/deposition under the plant canopy/bare soil riverbed; quantify the response of stems of the selected plant species under various flow conditions (from low to high flows). The purpose of this study is to provide floodplain managers and engineers with information on the impact of native vegetation on flood flow hydraulics, and information necessary to incorporate habitat concerns and benefits into the design and management of floodways and vegetated wetland habitats within the state of California. The study involved point velocity raw data measurements, hydraulic head measurements, soil erosion measurements, roughness coefficient estimations and characterization of plant canopy response to various flow regimes.

THROUGH-DELTA FACILITY WHITE STURGEON PASSAGE LADDER STUDY

The University of California, Davis (UCD) and the California Department of Water Resources (DWR), including biologists and engineers from both institutions, completed a research study to determine the feasibility of a sturgeon ladder passage and to evaluate its use with the Delta Cross Channel, or a Through-Delta Facility. Swimming performance tests to quantify the swimming capabilities of adult wild-caught white sturgeon (Acipenser transmontanus), and to identify physiological and behavioral parameters that may be used to design fish passage structures were completed. In addition to the performance, physiological and behavioral parameters, the hydraulic requirements of a passage structure were evaluated to determine the necessary energy dissipation essential to support sturgeon passage.

FISH TREADMILL STUDIES

Engineers and biologists from UCD, working with the California Department of Water Resources, designed and built a large fish treadmill to investigate swimming performance, behavior and physiology of fish in a two-vector flow field. The treadmill was used to study species and size specific behavioral response to a large fish screen. Also studied were velocity and screen exposure duration for various fish species. The study aimed to identify which factors influence successful fish protection and passage, and to provide information needed to design and operate effective fish screens.