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USGS2023

New maps of conductive heat flow in the Great Basin, USA: Separating conductive and convective influences

Geothermal well data from Southern Methodist University and the U.S. Geological Survey (USGS) were used to create maps of estimated background conductive heat flow across the Great Basin region of the western United States. These heat flow maps were generated as part of the USGS hydrothermal and Enhanced Geothermal Systems resource assessment process, and the creation process seeks to remove the influence of hydrothermal convection from the predictions of the background conductive heat flow. The heat flow maps were constructed using a custom-developed iterative process using weighted regression, in which convectively influenced outliers were de-emphasized by assigning lower weights to measurements with heat flow values further from the estimated local trend (e.g., local convective influence). The local linear weighted regression algorithm is two-dimensional locally estimated scatterplot smoothing where smoothness was controlled by varying the number of nearby wells used for each local interpolation. Three maps resulting from conductive heat flow models are detailed in this paper, highlighting the influence of measurement confidence. The three maps use either: measurements from all wells with equal weight (no confidence weights), or one of two different published categorization methods to de-emphasize low-quality measurements; one categorization method graded thermal gradient quality, the other categorization method graded thermal conductivity quality. Each map is an estimate of background conductive heat flow as a function of reported data quality, and a point coverage is also provided for all wells in the compiled dataset. The point coverage includes an important new attribute for geothermal wells: the residual, which can be interpreted as the departure of a well from the estimated background heat flow conditions, and the value of the residual may be useful in identifying the influence of fluids (hydrothermal or groundwater) on conductive heat flow. Of the three maps presented, the map that de-emphasized the impact of wells with low-quality thermal gradient measurements appears to perform best because it did not incorporate many of the wells in the Snake River Plain that do not penetrate the aquifer and are therefore very unlikely to reflect true conductive conditions.

Great Basin↗

USGS2020

Estimating the drivers of species distributions with opportunistic data using mediation analysis

Ecological occupancy modeling has historically relied on high-quality, low-quantity designed-survey data for estimation and prediction. In recent years, there has been a large increase in the amount of high-quantity, unknown-quality opportunistic data. This has motivated research on how best to combine these two data sources in order to optimize inference. Existing methods can be infeasible for large datasets or require opportunistic data to be located where designed-survey data exist. These methods map species occupancies, motivating a need to properly evaluate covariate effects (e.g., land cover proportion) on their distributions. We describe a spatial estimation method for supplementarily including additional opportunistic data using mediation analysis concepts. The opportunistic data mediate the effect of the covariate on the designed-survey data response, decomposing it into a direct and indirect effect. A component of the indirect effect can then be quickly estimated via regressing the mediator on the covariate, while the other components are estimated through a spatial occupancy model. The regression step allows for use of large quantities of opportunistic data that can be collected in locations with no designed-survey data available. Simulation results suggest that the mediated method produces an improvement in relative MSE when the data are of reasonable quality. However, when the simulated opportunistic data are poorly correlated with the true spatial process, the standard, unmediated method is still preferable. A spatiotemporal extension of the method is also developed for analyzing the effect of deciduous forest land cover on red-eyed vireo distribution in the southeastern United States and find that including the opportunistic data do not lead to a substantial improvement. Opportunistic data quality remains an important consideration when employing this method, as with other data integration methods.

eastern United States↗

USGS1985

Updating range surveys using a geographic information system

A spatial database was developed for the Fort Berthold Indian Reservation in North Dakota to demonstrate the use of a geographic information system for natural resource management. A key component of the digital database was a detailed soil survey. Range site boundaries were derived by aggregating soil mapping units on the basis on interpretations from the published soil surveys. The problem was that no range survey data including stocking rates and condition class were available for the soil-survey-derived range sites. The only available range survey was a survey that was based on range site delineations from a Missouri River Basin Inventory (MRBI) program conducted in 1961, prior to the availability of soil survey data. The MRBI survey information was correlated with the revised range sites derived from the soil surveys to device stocking rates and condition classes. A 1:24,000-scale map which included revised range site boundaries and management boundaries was produced for each township within the reservation. All polygons on the maps were uniquely labeled to permit discrimination of the potential differences in range site stocking rates due to grazing management practices. The maps and the associated polygon attribute data were merged with maps of the MRBI transect information to derive the stocking rate and condition class for each revised range site within a management unit. The resulting database components were a map of revised range site boundaries within management units and an associated tabular file containing attribute information including stocking rate and condition class.

North Dakota↗

USGS1993

Publications of the Branch of Atlantic Marine Geology for Calendar Year 1992

This U.S. Geological Survey Open-File Report contains a listing of publications authored or co-authored by members of the Branch of Atlantic Marine Geology and published in calendar year 1992. The Branch conducts a broad geologic and geophysical research and mapping program, primarily along the U.S. Atlantic Margin, in the Great Lakes, the Gulf of Mexico, the Caribbean and polar regions. A long range objective of this program is to develop a comprehensive understanding of the geology of the continental margin and a predictive capability to guide and assess the consequences of its use. Headquarters of the Branch of Atlantic Marine Geology are located in Woods Hole, MA., and personnel are located in Woods Hole, MA., St Petersburg, FL., Reston, VA., Denver, CO., and San Juan, Puerto Rico. A brochure describing the Branch of Atlantic Marine Geology may be obtained by writing to Chief, Branch of Atlantic Marine Geology, Quissett Campus, Woods Hole, MA 02543. Results of Branch investigations are distributed in a variety of ways, including maps, journal articles, abstracts and U.S.G.S. publications. Copies of U.S.G.S. Open File Reports may be obtained from the author. Book publications can be obtained from U.S. Geological Survey, Books and Reports Sales, Federal Center, Box 25425, Denver, CO 80225. Copies of U.S.G.S. Maps may be obtained from the U.S. Geological Survey, Map Sales, Federal Center, Box 25286, Denver, CO 80225.

Open-File Report↗

USGS1988

Drainage areas in the Vermillion River basin in eastern South Dakota

Above-normal precipitation in the northern portion of the Vermillion River basin from 1982 through 1987 caused substantial rises in lake levels in the Lake Thompson chain of lakes, resulting in discharge from Lake Thompson to the East Fork Vermillion River. Prior to 1986, the Lake Thompson chain of lakes was thought to be a noncontributing portion of the Vermillion River basin. To better understand surface drainage, the map delineates all named stream basins, and all unnamed basins larger than approximately 10 sq mi within the Vermillion River basin in South Dakota and lists by stream name the area of each basin. Stream drainage basins were delineated by visual interpretation of contour information of U.S. Geological Survey 7 1/2 minute topographic maps. Two tables list areas of drainage basins and reaches, as well as drainage areas above gaging stations. (USGS)

Open-File Report↗

USGS1984

Publications of the Geological Survey, 1983

This catalog is a list of (1) books and maps that were published during 1983, and (2) articles by Geological Survey personnel in non-Geological Survey journals and books that came to our attention in 1983; it supplements the permanent catalogs "Publications of the Geological Survey, 1879-1961" and "Publications of the Geological Survey, 1962-1970."