Geology topics
Research about Platte River
Source-linked reports with geographic coverage including Platte River.
Evaluation of models and data for assessing whooping crane habitat in the central Platte River, Nebraska
The primary objectives of this evaluation were to improve the performance of the Whooping Crane Habitat Suitability model (C4R) used by the U.S. Fish and Wildlife Service (Service) for defining the relationship between river discharge and habitat availability, and to assist the Service in implementing improved model(s) with existing hydraulic files. The C4R habitat model is applied at the scale of individual river cross-sections, but the model outputs are scaledup to larger reaches of the river using a decision support “model” comprised of other data and procedures. Hence, the validity of the habitat model depends at least partially on how its outputs are incorporated into this larger context. For that reason, we also evaluated other procedures including the PHABSIM data files, the FORTRAN computer programs used to implement the model, and other parameters used to simulate the relationship between river flows and the availability of Whooping Crane roosting habitat along more than 100 miles of heterogeneous river channels. An equally important objective of this report was to fully document these related procedures as well as the model and evaluation results so that interested parties could readily understand the technical basis for the Service’s recommendations.
Polycyclic aromatic hydrocarbons, aliphatic hydrocarbons, trace elements and monooxygenase activity in birds nesting on the North Platte River, Casper, Wyoming, USA
Tree swallow (Tachycineta bicolor) and house wren (Troglodytes aedon) eggs and chicks were collected near a refinery site on the North Platte River, Casper, Wyoming, USA and at a reference site 10 km upstream. Total polycylic aromatic hydrocarbon (PAH) concentrations in swallow and wren chicks were higher at the refinery site than at the reference site. Polycylic aromatic hydrocarbon concentrations in sediment and chick dietary samples were consistent with these findings. The general lack of methylated PAHs in sediment, diet, and bird carcasses suggested that the PAHs were derived from combustion and not from petroleum. The predominance of odd numbered aliphatic hydrocarbons and the low ratios (≤ 0.25) of pristane: n -C 17 and phytane: n -C 18 in chick and diet samples also suggested that swallow and wren chicks were not being chronically exposed to petroleum. Mean ethoxyresorufin- O -dealkylase and benzyloxyresorufin- O -dealkylase activities in tree swallow livers averaged nine times higher at the refinery site than at the reference site and were probably induced by exposure to PAHs. Trace element concentrations in eggs and livers of swallows and wrens were similar or greater at the reference site than at the refinery site. Selenium, strontium, and boron concentrations were elevated in eggs and livers of swallows and wrens at both the refinery and reference sites.
Areas of gain and loss along the Platte River, central Nebraska, spring 1999
In an effort to protect endangered and other wildlife species, the governors of Nebraska, Colorado, and Wyoming, and the Secretary of the U.S. Department of the Interior signed an agreement in 1997 (Platte River Endangered Species Partnership, 1997) to initiate the development of a basin-wide habitat recovery program for the central reaches of the Platte River in Nebraska. This agreement recognizes the need to maintain minimal flows in the central reaches of the Platte River. An understanding of the surface-water and ground-water interaction along the central reaches of the Platte River is critical to deliver water to the targeted habitat areas. Therefore, a study by the U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation and the U.S. Fish and Wildlife Service, was conducted to determine qualitatively the areas of gain and loss along the central Platte River between Gothenburg and Silver Creek, Nebraska (fig. 1). The purpose of this report is to present the results of the study.
Habitat selection and productivity of least terns on the lower Platte River, Nebraska
Least terns ( Sterna antillarum ) were studied on the lower Platte River, Nebraska, where this endangered population nests on natural sandbar habitat and on sandpit sites created by gravel dredging adjacent to the river. Theoretically terns should select habitats according to habitat suitability. However, the introduction of sandpits and conversion of tallgrass prairies along the river banks to agriculture, residential, and wooded areas may have affected terns' abilities to distinguish suitable habitat or the suitability of nesting habitats in general. I examined habitat selection and productivity of least terns to determine if terns selected habitat according to suitability (as indicated by productivity), what factors affected habitat selection and productivity, and if estimated productivity could support this population. Available habitats of both types were characterized and quantified using aerial videography (1989-90), and habitat use was assessed from census data (1987-90). Productivity of adults and causes and correlates of egg and chick mortality were estimated (1987-90). Population trend was assessed with a deterministic model using my estimates of productivity and a range of survival estimates for Laridae reported in the literature. Terns tended to use river sites with large midstream sandbars and a wide channel, and large sandpit sites with large surface areas of water relative to unused sites on both habitats. Number of sites and area of sand available were estimated using discriminant function analysis of variables quantified from video scenes of both habitats. Terns apparently did not use all potentially available sandbar and sandpit sites because discriminant function factor scores for used and unused sites overlapped broadly for both habitats. Terns did not prefer 1 habitat over the other. Although proportions of available sites used were greater on sandpits than on the river, proportions of available sand used did not differ between habitats. Proportion of terns using each habitat was similar to proportion of available sand on each habitat. The distribution of nest initiation dates and rates of colony-site turnover also were similar on both habitats. Productivity did not differ between habitats but varied significantly among sites. Nest success, fledging success, and fledglings per pair averaged 0.54, 0.28, and 0.47, respectively. Key factor analysis revealed that chick survival had a greater influence on production of fledglings (on both sandbars and sandpits) than did failure to produce a maximum clutch size or egg mortality. Most egg mortality was caused by predation on sandpits and by flooding on sandbars. Predation was suspected as the major cause of loss for chicks on both habitats. Path analysis revealed no strong or consistent correlations among mortality, numbers of nests and chicks, track trails of intruders into colonies, and habitat variables at colonies on either habitat. Theoretically, terns should not prefer a habitat when habitats are equally suitable if terns have had time to respond to habitat changes. Although sandbars and sandpits appeared equally suitable and terns did not prefer either habitat, local productivity will not support this population unless annual postfledging survival is higher than current estimates for the species. Population trend estimated with fledglings per pair = 0.50 was negative for all but the highest (ca 0.90) rates of annual postfledging survival. Furthermore, deterministic models like the one used in this study overstimate trend. Productivity insufficient to support the local population, in spite of habitat use that reflects habitat suitability, could be due to increased predation caused by habitat alteration adjacent to the river that may have changed the predator community. Alternatively, terns in this area could persist in spite of prevailing low productivity because they are relatively long-lived birds, if highly productive years occasionally occur or if this population is augmented by immigrants from elsewhere.
Prey availability for foraging Piping Plovers along the Platte River in Nebraska
No abstract available.
Platte River Forum for the Future: workshop model documentation
The Platte River Forum for the Future (PRFF) is an effort by the Nebraska Natural Resources Commission (NNRC) to bring together representatives of interests and agencies concerned with management of the Platte River and, assisted by various computer technologies, to reach some degree of agreement on the “best uses” of the remaining waters of the Platte. Simulation modeling is being used in this effort as a focal point for developing a common understanding of the behavior of the Platte River system, synthesizing existing information, identifying additional needed information, and analyzing the potential consequences of various management alternatives. The NNRC initiated the project in August 1982 by convening a workshop for interested parties in Grand Island, Nebraska. This workshop was devoted to construction of a preliminary simulation model describing the Platte River system. A group of facilitators/modelers from the U.S. Fish and Wildlife Service (FWS) assisted participants in translating their understanding of the Platte River into the framework of the model. In October 1982, FWS personnel began a process of training several people from Nebraska in the use of the model. At that time, minor revisions and corrections were made in the model and various development scenarios were prepared for discussion with participants at a second workshop, which was held in early November 1982. The purpose of this report is to document the status of the PRFF simulation model as of the end of the November 1982 meeting. We emphasize that the intent is not to describe a final product. Except for minor revisions and correction of obvious errors, the model described herein is that which existed at the end of the August workshop. The model contains the foundation for a comprehensive aid to decisionmakers, but at this time it is preliminary in nature, needing refinement and verification before it can be truly useful in analyzing management alternatives. The purpose of this report is to provide a solid foundation for that important future work. The report is divided into three basic parts. The first is a brief overview of the various components of the model and how they fit together. It is intended for those who are not particularly interested in the details of model formulation. The second is a detailed discussion of the logic, assumptions, equations, and data used in constructing the model. This detailed description is also referenced to specific sections of the third part, which is a set of appendices containing listings of the computer code as it presently exists.
Simulated hydrologic effects of possible ground-water and surface-water management alternatives in and near the Platte River, south-central Nebraska
Digital computer models were developed and used to simulate the hydrologic effects of hypothetical water-management alternatives on the wetland habitat area near Grand Island, Nebr. Areally distributed recharge to and discharge from the aquifer system adjacent to the Platte River between Overton and Grand Island were computed for four hypothetical water-management alternatives. Using stream-aquifer response functions, the stream depletions resulting from the different alternatives ranged from 53,000 acre-feet per year for increased surface-water irrigation to 177,000 acre-feet per year for increased ground-water pumpage. Current conditions would result in stream depletions of 125,000 acre-feet per year. Using the relationship between discharge and river stage, frequency curves of the stage in the river near the wildlife habitat area were computed using a 50-year sequence of historical streamflow at Overton, minus the stream depletions resulting from various management practices. For the management alternatives previously discussed, differences in the stage-frequency curves were minimal. For comparative purposes, three additional water-management alternatives whose application would change the incoming streamflow at Overton were simulated. Although in these alternatives the amounts of water that were diverted or imported were similar to the amounts in the previous alternatives, their effects on the stage-frequency curves were much more dramatic. (USGS)
Sediment investigations of the Platte River near Overton, Nebraska
This report contains results of sediment-transport investigations on the Platte River near Overton,. Nebr. from January 1950 to September 1953. The basic data of suspended-sediment studies, results of bed-material analyses, and determinations of water-surface slopes from staff readings are given. The data indicate that a reliable determination of suspended sediment, hence total load, is difficult. Because of the nature of the river at the station and the limited scope of the investigations, the suspended-sediment data may not be representative. The Platte River is characterized by a wide braided channel, a small hydraulic radius, low banks, and a wide flood plain. (See figs. 1 and 2.,) The river bed is composed of coarse to fine sands. Near Overton, natural flow of the river is controlled or modified by diversions, storage reservoirs, power development, return flow from irrigation, and withdrawals of ground water. A temporary jetty was extended into the river below the bridge during the summer of 1952 as part of commercial sand pumping operations. Beavers carry on active construction in the narrows and shallows, particularly upstream from the sampling section. Daily fluctuations in water discharge at the gaging station at the bridge are caused by regulation of the flow, mainly from the generation of power by release of water from a reservoir The water discharge at the station begins increasing about 9:30 a.m., reaches a crest about 2:00 p.m and then immediately recede. Weekly water-discharge measurements of alternate high and low stages indicate a daily variation from 200 to more than 1,000 cfs. During spring summer, and fall increases in water dis charge are also caused by thunderstorm activity in the area.