Bathymetric and Velocimetric Survey and Assessment of Habitat for Pallid Sturgeon on the Mississippi River in the Vicinity of the Proposed Interstate 70 Bridge at St. Louis, Missouri (original) (raw)
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Habitat assessment, Missouri River at Hermann, Missouri
Open File Report, 2002
This report documents methods and results of aquatic habitat assessment in the Missouri River near Hermann, Missouri. The assessment is intended to improve understanding of spatial and temporal variability of aquatic habitat, including habitats thought to be critical for the endangered pallid sturgeon (Scaphirhynchus albus). Physical aquatic habitat-depth, velocity, and substrate-was assessed around 9 wing dikes and adjacent to the U.S. Route 19 bridge, at discharges varying from 44,000 cubic feet per second (cfs) to 146, 000 cfs during August 2000-May, 2001. For the river as a whole, velocities are bi-modally distributed with distinct peaks relating to navigation channel and wing-dike environments. Velocities predictably showed an increasing trend with increasing discharge. Substrate within wing dikes was dominated by mud at low discharges, whereas the navigation channel had patches of transporting sand, rippled sand, and coarse sand. Discharges that overtopped the wing dikes (about 93,000 cfs, March 2001) were associated with increases of patchy sand, rippled sand, and coarse sand within the wing dikes. When flows were substantially over the wing dikes (146,000 cfs, May 2001) substrates within most wing dikes showed substantial reorganization and coarsening. The habitat assessment provides a geospatial database that can be used to query wing dikes for distributions of depth, velocity, and substrate for comparison with fish samples collected by US Fish and Wildlife Service biologists (Grady and others, 2001). In addition, the assessment documented spatial and temporal variation in habitat within the Hermann reach and over a range of discharges. Measurable geomorphic change-alteration of substrate conditions plus substantial erosion and deposition-was associated with flows equaled or exceeded 12-40% of the time (40-140 days per year). Documented geomorphic change associated with high-frequency flows underscores the natural temporal variability of physical habitat in the Lower Missouri River.
Transactions of the American Fisheries Society, 1995
We conducted a gill-net survey and used sonic tracking to document the distribution and movements of adult shortnose sturgeons Acipenser brevirostrum and juvenile Atlantic sturgeons Acipenser oxyrhynchus in the lower Cape Fear River, North Carolina. Shortnose sturgeons were rare; only eight fish were captured from 1990 to 1993. The five fish we tracked occupied river kilometer 16-96 from early January to May. The presence of gravid females and the rapid (11.5-27.0 km/d), directed upstream migrations we observed provided evidence that shortnose sturgeons may attempt to reproduce in this drainage. We also documented the disruption of spawning migrations by dams and incidental gill-net capture, which may prevent these fish from ever reaching their spawning grounds. Atlantic sturgeon juveniles were relatively common and preferred deep areas (>IO m) in the vicinity of the salt water-fresh water interface (km 46). In summer they held position for extended periods and apparently fasted, but were more active (1.3 km/d) and ranged over a greater area during cooler water temperatures in fall, winter, and spring. Both species occupied regularly dredged areas and were present during dredging operations in the Wilmington Harbor. 49 is dredged to an average depth of 4 m, but there are numerous deep holes (>10 m) throughout. Lock and Dam 1, one of three navigational locks and dams built between 1915 and 1934, defines the upper limit of our study area (km 96). The maximum height of this dam is 4 m. Methods Gill-net survey.-We conducted a gill-net survey from May 1990 to May 1992. All sinking gill nets were 50 m long and 3.5 m deep. We used two sizes of monofilament mesh gill nets: 14-cm stretched mesh (year-round) and 5.1-cm stretched mesh (April-November). One trammel net (inside panel, 7.6-cm stretched mesh; outside panels, 20.3-cm stretched mesh) was also operated yearround. The gill nets were set perpendicular to the current, from 2 to 20 m deep. The trammel net
Evaluation of the Missouri River shallow water habitat using a 2D‐hydrodynamic model
River Research and Applications, 2011
Many of the Upper Missouri River dikes have been notched to create additional shallow water habitat (SWH, operationally defined as areas in the stream with depth < 1.5 m, and velocity < 0.75 m s−1) for fish populations. The goal of this study was to quantify the additional SWH gained from notching these dikes and to evaluate their performance under different flow conditions. A coupled field and numerical study was performed on a reach of the Missouri River, near Nebraska City, NE, which contains a number of dikes notched in 2004. The numerical simulations showed that the SWH criterion for depth was more difficult to satisfy in the study reach than the SWH criterion for velocity. Notching the dikes resulted in a slight shift of the bankline due to local erosion in the vicinity of the dikes and the formation of scour holes downstream of the notches. Results from the study suggested that notching the dikes had limited impact on the SWH because the area gained from the bankline sh...
Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2012
Scientific Investigations Report, 2015
Streambed scour potential was evaluated at 18 riverand stream-spanning bridges in Alaska that have unknown foundation details or a lack of existing scour analysis. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 17 bridges, and pier scour was calculated for 7 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites with overtopping floods (where the modeled water surface was higher than the superstructure of the bridge). In most cases, hydraulic models of the 1-and 0.2-percent annual exceedance probability floods (also known as the 100-and 500-year floods, respectively) were used to derive hydraulic variables for the scour calculations. Alternate flood values were used in scour calculations for sites where smaller floods overtopped a bridge or where standard floodfrequency estimation techniques did not apply. Scour was also calculated for large recorded floods at several sites. Equations for scour in cohesive soils were used for sites where streambed sediment was silt-sized or smaller. Channel instability at four sites was related to human activities (in-channel mining, dredging, and channel relocation). Three of the dredged sites are located on active unstable alluvial fans and were graded to inhibit aggradation. The trend toward aggradation during major floods at these sites greatly reduces confidence in scour estimates. Vertical contraction and pressure flow occurred during 1 percent or smaller annual exceedance probability floods at five sites, including three aggradation sites. Contraction scour exceeded 5 feet at two sites, and total scour at piers (pier scour plus contraction scour) exceeded 5 feet at two sites. Debris accumulation increased calculated pier scour at six sites by an average of 1.2 feet. Total scour at abutments including contraction scour exceeded 5 feet at seven sites. Scour estimates seemed excessive at aggradation sites where upstream sediment supply controls scour and deposition processes, at cohesive soil sites where conservative assumptions were made for soil strength and flood duration, and for abutment scour at sites where failure of the embankment and attendant channel widening would reduce scour.
Persistence of a scour hole on the East Channel of the Mackenzie Delta, N.W.T
Canadian Journal of Civil Engineering, 2000
Anomalies in the bathymetry of river channels are of great practical concern for designing sub-bed pipeline crossings. Of particular interest is the long-term stability of deep holes. Bathymetric evidence indicates that one unusually deep hole in the East Channel of the Mackenzie River, referred to as a scour hole, has existed as early as 1956. Detailed hydraulic and morphologic data were first collected in 1985, and again in 1992 to assess the spatial and temporal stability of the feature. Even with a record flood on the Mackenzie River in 1988, the hole, with a maximum depth approaching 30 m, was vertically stable over the 7-year period. However, lateral erosion and sedimentation have resulted in a shift in the horizontal position of the scour hole, with a maximum horizontal erosion of approximately 2 m/a. The average rate of lateral outward movement was observed to be 0.8 m/a.Key words: Mackenzie Delta, rivers, fluvial sediment, channel stability, scour, scour hole.
Journal of Hydrology, 2013
The large Mississippi River flood in 2011 was notable in the lowermost Louisiana, USA reach for requiring operation of several flood control structures to reduce stress on artificial levees: the largest diversion went through the gated Bonnet Carré Spillway, which was opened for 42 days in May and June. The removal of approximately 20% of the total flood discharge from the river provided an opportunity to examine the impact of large water diversion on the sediment transport capacity of large rivers. Boat-based, acoustic and water and bed sampling surveys were conducted in the Mississippi River channel adjacent to the Spillway immediately prior to the opening of the structure, at full capacity, and immediately following (June 2011) and 1 year after (June 2012) closure. The surveys were designed to examine (1) elevation change of the channel bed due to scour or aggradation of sediment, and (2) suspended and bedload transport variability upriver and downriver of the Spillway. The results indicate that approximately 9.1 million tons of sand were deposited on the channel bed immediately downriver of the water exit pathway and extending at least 13 km downriver at a rapidly and progressively reducing magnitude per river kilometer. The surficial deposit was of finer grain size than the lateral sand bars in the channel upriver of the structure. We argue the deposit was largely delivered from suspension derived from the observed deflation of lateral bars upstream of the diversion point, rather than from sand arriving from the drainage basin. Approximately 69% of the 2011 flood deposit was removed from the 13 km downstream reach between June 2011 and June 2012. We conclude that the source of the channel deposit was the reduction in stream power, and, thus, in the sediment transport capacity of the Mississippi, associated with the water withdrawal. The re-entrainment of this material in the following flood year indicates the system rapidly re-establishes an equilibrium to pre-opening conditions. Future diversions in the river for coastal restoration will have to address this issue to maintain a deep draft navigation channel in the Mississippi River.
Bedform transport rates for the lowermost Mississippi River
Journal of Geophysical Research, 2008
New methods of data collection and processing are developed to provide quantitative, reach-scale measurements of bedform transport mass within the tidally influenced Mississippi River. A multibeam swath profiler was used to collect daily bathymetry over a range of water discharges, and bed elevation changes induced by dune migration are measured. These values are coupled with bulk physical properties of the bed sediment to constrain mass flux, and annual bedform transport is estimated at 2.2 × 106 metric tons (MT). The total annual sand flux from the Mississippi River, calculated by combining measured bedform transport rates and suspended sediment flux, is estimated to be 20 × 106 MT. Survey data also provide information about the spatial distribution of dunes across the channel bottom. Straight reach segments are commonly mantled by dunes for the entire cross section, while bends are typically areas of focused scour devoid of bedforms. Presumably, any sediments associated with migrating dunes are propelled into suspension within bends before redepositing in the subsequent straight reach. Movement via suspension is therefore an important component for the downriver transport of bed materials in the lower Mississippi River.