Geology topics

Research about Montana, Nebraska, North Dakota, South Dakota

Source-linked reports with geographic coverage including Montana, Nebraska, North Dakota, South Dakota.

3 recordsLinked to original sources

USGS2012

Extending a prototype knowledge and object based image analysis model to coarser spatial resolution imagery: An example from the Missouri River

A prototype knowledge- and object-based image analysis model was developed to inventory and map least tern and piping plover habitat on the Missouri River, USA. The model has been used to inventory the state of sandbars annually for 4 segments of the Missouri River since 2006 using QuickBird imagery. Interpretation of the state of sandbars is difficult when images for the segment are acquired at different river stages and different states of vegetation phenology and canopy cover. Concurrent QuickBird and RapidEye images were classified using the model and the spatial correspondence of classes in the land cover and sandbar maps were analysed for the spatial extent of the images and at nest locations for both bird species. Omission and commission errors were low for unvegetated land cover classes used for nesting by both bird species and for land cover types with continuous vegetation cover and water. Errors were larger for land cover classes characterized by a mixture of sand and vegetation. Sandbar classification decisions are made using information on land cover class proportions and disagreement between sandbar classes was resolved using fuzzy membership possibilities. Regression analysis of area for a paired sample of 47 sandbars indicated an average positive bias, 1.15 ha, for RapidEye that did not vary with sandbar size. RapidEye has potential to reduce temporal uncertainty about least tern and piping plover habitat but would not be suitable for mapping sandbar erosion, and characterization of sandbar shapes or vegetation patches at fine spatial resolution.

Montana, Nebraska, North Dakota, South Dakota↗

USGS1982

Some observations on the ecology and fish management of reservoirs in the United States

By 1980 there were 1,608 reservoirs (over 202 ha each) with a surface area of 4 million ha in the United States. Construction of new reservoirs has decreased in recent years because of the lack of suitable sites and the opposition of environmental interests. Reservoirs have characteristics of both lacustrine and riverine ecosystems. Reservoirs have been segmented into riverine, transitional and lacustrine zones for simulation modelling.Fish and plankton production increases rapidly after initial impoundment and then decreases and stabilizes at lower levels. Decreases in the number of fish species and in fish biomass following impoundment are caused by reduced quantity and quality of spawning and nursery habitat and decreased detrital input. Plankton populations can be followed downstream in a series of reservoirs and increases in abundance were associated with the inundation of vegetation or the introduction of nutrients.In addition to water level management, the most effective fish management programs have included introducing new fishes, developing vegetation or building structures on the reservoir bottom. Considerable progress has been made in predicting the effects of environmental parameters on fish production.

Montana, Nebraska, North Dakota, South Dakota↗

USGS1980

Effects of post-impoundment shore modifications on fish populations in Missouri River reservoirs

In the Missouri River main stem reservoirs in Montana, North Dakota, and South Dakota, hydrodynamic processes have decreased the lengths of shorelines and changed their configuration during the first 20 to 25 years of impoundment. Shale shores of Lakes Fort Peck, Oahe, Sharpe, and Francis Case were rapidly eroded by wave action and water level fluctuation. Banks slumped, embayments filled, and stumps and debris were covered by sediment. Shale shores developed mean slopes of 5-7% in sections of reservoirs with 10- to 25-km fetches and more than 10% in sections with 3- to 7-km fetches. Glacial till tended to armor the shorelines and deter their degradation in all reservoirs. Bank-cutting was particularly severe up to 1973 in the readily erodible Fort Union sediments along Lake Sakakawea. Water level fluctuation retarded the development of stable shores. Some aquatic vegetation developed along shorelines and in shallow sections of reservoirs in which water levels fluctuated little. Substrate suitable for terrestrial vegetation did not develop along the shores of fluctuating reservoirs, except where alluvial deposits were present. Physical changes of the shore probably influenced fish abundance and species composition primarily by changing the quality and quantity of spawning and nursery habitat. Species that appeared to be adversely affected by shore changes required protected embayments or flooded vegetation for reporduction: white crappie, Pomoxis annularis : black crappie, P. nigromaculatus : yellow perch, Perca flavescens : northern pike, Esox lucius : bigmouth buffalo, Ictiobus cyprinellus : small mouth buffalo, I. bubalus : and carp, Cyprinus carpio . Fish that spawn in tributaries or on rocky shores were not greatly influenced by shore changes (although the growth rate of several species were slowed): sauger, Sander canadensis : channel catfish, Ictalurus punctatus : white bass, Morone chrysops : goldeye, Hiodon alosoides : and river carpsucker, Carpiodes carpio . One species, the walleye, Stizostedion v. vitreum , appeared to be benefited from the shore changes. Physical changes along shores have not been adequately addressed in reservoir ecological planning. Fish population data collected before reservoir shores have reached a reasonable degree of stability do not provide a reliable estimate of the ultimate species composition in a reservoir.

Montana, Nebraska, North Dakota, South Dakota↗