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Research about Iowa, Kansas, Missouri, Nebraska

Source-linked reports with geographic coverage including Iowa, Kansas, Missouri, Nebraska.

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Spatial and temporal variation in length-weight relationships of age-0 Scaphirhynchus sturgeon in the lower Missouri River

Length-weight relationships can be useful tools for assessing fish condition. We developed these equations (W = a L b ) for wild-caught age-0 (4.1–12.0 cm) Scaphirhynchus sturgeon from eight reaches spanning over 750 river km of the lower Missouri River from 2014 to 2017. We used nonlinear modeling to estimate the constant ( a ) and exponent ( b ) of the LW equation for each reach to assess potential spatial differences. We also assessed long-term temporal effects by estimating these parameters by year at Lexington reach, which is located in the middle of our sampling area and was the only reach sampled all 4 y. Constant and exponent estimates from linearized regressions varied by reach and were inversely related during the spatial analyses. Similarly, parameter estimates were also inversely related and varied among years during the temporal analysis at Lexington. To account for the relationship between constant and exponent values, we used predicted weights at 2 cm increments (4.1–12.0 cm) for the spatial analysis (by reach) and for the temporal analysis (by year). During the 2014 and 2015 spatial analyses, weights varied by size but were usually higher in Lexington and Glasgow, which were the furthest upstream reaches sampled during those years. During 2016 and 2017, Lexington was the furthest downstream reach sampled but did not consistently yield relatively high predicted weights. Temporal analysis at Lexington yielded higher predicted weights for 2014–2015 compared to 2016–2017 for higher size categories (10- and 12-cm). In general our results suggest differences in body condition among reaches and years in the lower Missouri River. Further research is needed to identify the specific mechanisms driving spatial and temporal L-W relationship differences observed and to determine if differences in predicted body conditions affect long-term survival and recruitment of age-0 Scaphirhynchus sturgeon. Currently, factors influencing age-0 Scaphirhynchus sturgeon condition and growth are unknown and this work serves to highlight knowledge gaps regarding factors influencing Scaphirhynchus sturgeon recruitment.

Iowa, Kansas, Missouri, Nebraska

Occurrence and transport of nutrients in the Missouri River Basin, April through September 2011

Heavy snow and early spring rainfall generated substantial amounts of runoff and flooding in the upper part of the Missouri River Basin in 2011. Spring runoff in the upper and middle parts of the basin exceeded the storage capacity of the Missouri River reservoirs and unprecedented amounts of water were released into the lower parts of the basin resulting in record floods from June through September on the Missouri River in Iowa and Nebraska and extending into Kansas and Missouri. Runoff from the Missouri River Basin in April through September 2011 was 8,440,000 hectare meters (68,400,000 acre feet) and was only exceeded during flooding in 1993 when runoff was 11,200,000 hectare meters (90,700,000 acre feet). Nitrate and total phosphorus concentrations in the Missouri River and selected tributaries in April through September, 2011 generally were within the expected range of concentrations measured during the last 30 years. Substantial discharge from the upper and middle parts of the Missouri River Basin resulted in nitrate concentrations decreasing in the lower Missouri River beginning in June. Concentrations of nitrate in water entering the Mississippi River from the Missouri River were less in 2011 than in 1993, but total phosphorus concentrations entering the Mississippi River were substantially greater in 2011 than in 1993. The Missouri River transported an estimated 79,600 megagrams of nitrate and 38,000 megagrams of total phosphorus to the Mississippi River from April through September 2011. The nitrate flux in 2011 was less than 20 percent of the combined total from the Upper Mississippi and Missouri River Basins. In contrast, the total phosphorus flux of 38,000 megagrams from the Missouri River constituted about 39 percent of the combined total from the Upper Mississippi and Missouri River Basins during April through September 2011. Substantially more nitrate but less total phosphorus was transported from the Missouri River Basin during the historic 1993 than during the 2011 flood. Greater runoff from the lower part of the basin contributed to the greater nitrate transport in 1993. In addition to the differing amounts of runoff and the source of flood waters, changes in land use, and management practices are additional factors that may have contributed to the difference in nitrate and total phosphorus flux between the 1993 and 2011 floods.

Iowa, Kansas, Missouri, Nebraska

Physical habitat dynamics in four side-channel chutes, lower Missouri River

Construction of the side-channel chutes has become a popular means to rehabilitate habitate of the Lower Missouri River. We studied various aspects of hydrology, hydraulics, and geomorphology of four side-channel chutes to document a range of existing conditions in the Lower Missouri River. The Cranberry Bend side-channel chute has existed for at least 40 years and is an example of a persistent, minimally engineered chute. The Lisbon Bottom side-channel chute is a young chute, created by extreme floods during 1993 – 1996, and allowed to evolve with minimum engineering of inlet and outlet structures. The Hamburg Bend and North Overton Bottom side-channel chutes were constructed in 1996 and 2000, respectively, as part of the Missouri River Bank Stabilization and navigation Fish and Wildlife Mitigation Project. These side-channel chutes provide increased areas of sandbars and shallow, slow water – habitats thought to be substantially diminished in the modern Missouri River. Depths and velocities measured in side-channel chutes are also present in the main channel, but the chutes provide more areas of slow, shallow water and they increase the range of discharges over which shallow, slow water is present. The 3.6 km long Lisbon Bottom chute provides as much as 50% of the entire shallow water habitat that exists in the encompassing 15 km reach of the river. At Cranberry Bend and Lisbon Bottom, the side-channel chutes provided 10 – 40% of the availabile sandbar area in the reach, depending on discharge. Each of the side-channel chutes shows evidence of continuing erosion and deposition. The longevity and the Cranberry Bend chute attests to dynamic stability – that is, a chute that maintains form and processes while shifting in position. The Hamburg chute similarly shows evidence of lateral movement and construction of flood plain to compensate for erosion. The Lisbon Bottom chute – the most intensively studied chute – appears to have achieved an equilibrium width and continues to migrate slowly; however, evidence of aggradation indicates that the chute has not reached an ultimate form, and may be continuing to adjust to altered hydrology and sediment availability. The North Overton Bottoms chute is the newest in the study. In its originally constructed form, the North Overton Bottoms pilot chute was extremely stable, even while being subjected to two floods in excess of 2-year recurrence interval and after accumulating large, potentially destabilizing large woody debris jams. Ongoing adaptive re-engineering of the North Overton Bottoms chute has prevented assessment of how the chute might have adjusted its form in the absence of intervention.

Iowa, Kansas, Missouri, Nebraska