Geology topics

Timothy Wyant

Publications and source records attributed to Timothy Wyant.

8 recordsLinked to original sources

USGS1982

Investigation of trends in flooding in the Tug Fork basin of Kentucky, Virginia, and West Virginia

Statistical analysis indicates that the average size of annual flood peaks of the Tug Fork (West Virginia and Kentucky) has been increasing. However, additional statistical analysis does not indicate that flood levels exceeded typically once or twice a year in the period 1947-1979 are any more likely to be exceeded now than in 1947. Possible trends in stream-channel size are also investigated at three locations. No discernable trends in channel size are noted. Further statistical analysis of the trend in the size of annual flood peaks shows that much of the annual variation is related to nearby rainfall and to the "natural" hydrologic response in a relatively undisturbed sub-basin. However, some statistical indication of trend persists after accounting for these natural factors, though the indication is of borderline statistical significance. This suggests the need for further study in the basin that may relate flood magnitudes to both rainfall and to land use.

Kentucky, Virginia, West Virginia↗

USGS1982

The oilspill risk analysis model of the U. S. Geological Survey

The U.S. Geological Survey has developed an oilspill risk analysis model to aid in estimating the environmental hazards of developing oil resources in Outer Continental Shelf (OCS) lease areas. The large, computerized model analyzes the probability of spill occurrence, as well as the likely paths or trajectories of spills in relation to the locations of recreational and biological resources which may be vulnerable. The analytical methodology can easily incorporate estimates of weathering rates , slick dispersion, and possible mitigating effects of cleanup. The probability of spill occurrence is estimated from information on the anticipated level of oil production and method of route of transport. Spill movement is modeled in Monte Carlo fashion with a sample of 500 spills per season, each transported by monthly surface current vectors and wind velocities sampled from 3-hour wind transition matrices. Transition matrices are based on historic wind records grouped in 41 wind velocity classes, and are constructed seasonally for up to six wind stations. Locations and monthly vulnerabilities of up to 31 categories of environmental resources are digitized within an 800,000 square kilometer study area. Model output includes tables of conditional impact probabilities (that is, the probability of hitting a target, given that a spill has occurred), as well as probability distributions for oilspills occurring and contacting environmental resources within preselected vulnerability time horizons. (USGS)

Professional Paper↗

USGS1982

Investigation of trends in flooding in the Tug Fork basin of Kentucky, Virginia, and West Virginia

Statistical analysis indicates that the average size of annual-flood peaks of the Tug Fork (Ky., Va., and W. Va.) has been increasing. However, additional statistical analysis does not indicate that the flood levels that were exceeded typically once or twice a year in the period 1947-79 are any more likely to be exceeded now than in 1947. Possible trends in streamchannel size also are investigated at three locations. No discernible trends in channel size are noted. Further statistical analysis of the trend in the size of annual-flood peaks shows that much of the annual variation is related to local rainfall and to the 'natural' hydrologic response in a relatively undisturbed subbasin. However, some statistical indication of trend persists after accounting for these natural factors, though it is of borderline statistical significance. Further study in the basin may relate flood magnitudes to both rainfall and to land use.

Water Supply Paper↗

USGS1978

An oilspill risk analysis for the eastern Gulf of Mexico (proposed sale 65) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Eastern Gulf of Mexico Outer Continental Shelf lease area. The study analyzed the probability of spill occurrence, likely paths of the spills, and locations in space and time of such objects as recreational and biological resources likely to be vulnerable. These results combined to yield estimates of the overall oilspill risk associated with development of the proposed lease area. This risk is compared to the existing oilspill risk from existing leases in the area. The analysis implicitly includes estimates of weathering rates and slick dispersion and an indication of the possible mitigating effects of cleanups.

Gulf Of Mexcio↗

USGS1978

Calibration of a simple oilspill trajectory model using the Argo Merchant spill

An oil spill risk analysis was conducted to determine the relative envionmental hazards of developing oil in different regions of the Eastern Gulf of Mexico Outer Continental Shelf lease area. The study analyzed the probability of spill occurrence, likely paths of the spills, and locations in space and time of such objects as recreational and biological resources likely to be vulnerable. These results combined to yield estimates of the overall oilspill risk associated with development of the proposed lease area. This risk is compared to the existing oilspill risk from existing leases in the area. The analysis implicityly includes estimates of weathering rates and slick dispersion and an indication of the possible mitigating effects of cleanups. (Woodard-USGS)

Open-File Report↗

USGS1978

An oilspill risk analysis of the Mid-Atlantic (Proposed Sale 49) outer continental shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the mid-Atlantic Outer Continental Shelf lease area. The study analyzed the probability of spill occurrence, likely paths of the spilled oil, and locations in space and time of recreational and biological resources that are likely to be vulnerable. These results are combined to yield estimates of the overall oilspill risk associated with development of the proposed lease area. The analysis implicitly includes estimates of weathering rates and slick dispersion and an indication of the possible mitigating effects of cleanups. Assuming that economically recoverable amounts of petroleum are found in the area, the leasing of the tracts proposed for sale 49 will increase the expected number of spills by about 20-25 percent over the number expected from the existing (sale 40) leases. The probability that an object such as land will be contacted by a spill is increased by at most five percentage points. (Woodard-USGS)

Water-Resources Investigations Report↗

USGS1978

An oilspill risk analysis for the southern California (proposed sale 48) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Southern California Outer Continental Shelf lease area. The study analyzed the probability of spill occurrences, likely paths of the spilled oil, and locations in space and time of such objects as recreational and biological resources likely to be vulnerable. These results combined yield estimates of the overall oilspill risks associated with development of the proposed lease area. The analysis implicitly includes estimates of weathering rates and slick dispersion and an indication of the p ossible mitigating effects of cleanups. The leasing of the tracts p roposed for Sale 48 will increase the expected number of spills by about 50-55% over the number expected from the existing Federal leases. The probability that an object, such as land, will be contacted by a spill is increased by less than 17 percentage points; however, this increase varies greatly for the different objects.

California↗

USGS1977

An oilspill risk analysis for the western Gulf of Alaska (Kodiak Island) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine relative environmental hazards of developing oil in different regions of the Western Gulf of Alaska Outer Continental Shelf lease area. The study analyzed probability of spill occurrence, likely path of pollutants from spills, and locations in space and time of recreational and biological resources likely to be vulnerable. These results are combined to yield estimates of the overall oilspill risk associated with development of the lease area. While the analysis includes estimates of weathering rates and slick dispersion, the methodology has not yet been developed to analyze the mitigating effects of cleanups which if taken into account would reduce the impact probabilities.

Alaska↗