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At least 1,495 records · Page 83Linked to original sources
USGS1981

Land application of domestic wastewater in Florida--statewide assessment of impact on ground-water quality

In Florida domestic waste water is being applied to the land for disposal and reuse. State and Federal regulations favor land-application methods over other advanced waste water treatment practices. Despite the increasing use of this alternative technology, little is known about localized effects on groundwater quality. This report documents the extent of land-application practices in Florida and summarizes case study information on some of the more adequately monitored site throughout the State. More than 2,500 sites in Florida are permitted by the Department of Environmental Regulation for applying domestic waste water to the land. The majority (more than 1,700 sites), classified as infiltration ponds, are concentrated in central and southern Florida. More than 560 sites classified as drainfields, and more than 250 sites classified as irrigation sites, are located primarily in central Florida. An estimated 150 million gallons per day of domestic waste water, after required secondary treatment, are applied to Florida soils. Despite the large numbers of sites and the considerable volume of waste water utilized, little is known about potential impact on groundwater quality. At the few sites where observation wells have been drilled and local groundwater quality monitored, no significant deterioration of water quality has been detected. (USGS)

Water-Resources Investigations Report↗
USGS1983

Effects of specific land uses on nonpoint sources of suspended sediment, nutrients, and herbicides, Pequea Creek basin, Pennsylvania, 1979-80

The Susquehanna River Basin Commission and the U.S. Environmental Protection Agency cooperated with the U.S. Geological Survey in a study to quantify nonpoint-source loadings from an agricultural area in Pennsylvania. Pequea Creek, a tributary to the Susquehanna River, drains a 154-square mile agricultural area in Lancaster County, Pennsylvania. Previous studies defined the Pequea Creek basin as a contributor of sediment, nutrients, and pesticides from nonpoint sources to the Susquehanna River. The purpose of this intensive watershed investigation was to determine the effects of various land uses on water quality of receiving streams. Streamflow was measured and monthly base-flow samples and water-weighted composite storm samples were analyzed for suspended sediment, nutrients, organic carbon, and triazine herbicides. Constituent loadings were calculated to quantify their discharge from the entire Pequea Creek basin and from four specific subbasins: forest, cornfield, rural residential, and pasture. Soil samples were analyzed for nutrients and selected herbicides, and land use and application data were collected to determine the source of loadings. Precipitation amounts and chemistry were also measured. Precipitation and streamflow were below average for much of the investigation period, May 1979 to December 1980. The annual precipitation for 1980 was 10 inches below normal, with drought conditions the last half of the year. During base flow, the highest concentrations of individual constituents generally observed were: 4.0 milligrams per liter total organic nitrogen and 1.4 milligrams per liter total phosphorus from the downstream pasture site; 24 milligrams per liter total nitrate nitrogen and 3.9 micrograms per liter total atrazine from the cornfield site; and 0.5 micrograms per liter total prometone, and 2.3 micrograms per liter total simazine from the residential site. Nearly all total nitrate nitrogen concentrations from the cornfield site during base flow were about double the U.S. Environmental Protection Agency (1977) criterion of 10 milligrams per liter. The highest constituent concentrations found in composite storm samples were nearly all in samples from the cornfield site. The highest concentrations found were: 16,000 milligrams per liter suspended sediment, 54 milligrams per liter total organic nitrogen, 41 milligrams per liter total nitrate nitrogen, 19 milligrams per liter total phosphorus, and 200 micrograms per liter total atrazine. The highest concentrations found in composite storm samples for total prometone was 6.4 micrograms per liter at the residential site and for total simazine was 4.8 micrograms per liter at the downstream pasture site. Generally, concentrations of all the constituents, except nitrate, were higher during storms than during base flow at all sites. Total concentrations of the constituents increase during storms predominantly due to increases in suspended concentrations. The highest storm concentrations of most constituents occurred at the cornfield site. Fertilizer and herbicide applications increase the available sources of nutrients and herbicides for transport to the stream. The highest phosphorus, atrazine, and suspended-sediment concentrations at the cornfield site occurred during intense storms soon after application and planting. Constituent yields (tons per square mile) from storms, about evenly distributed throughout the basin, were compared from the other specific land-use sites to the forest site, which represents a relatively undisturbed land use. During storms, yields for suspended sediment, total organic nitrogen, and total phosphorus were highest for the pasture and lowest for the forest site. Total nitrate-nitrogen yields were highest for the cornfield and about the same for the forest and residential sites. Yields of total organic carbon were about the same for the cornfield and residential sites, which were both slightly higher than the forest

Water-Resources Investigations Report↗
USGS1986

Geologic, hydrologic, and cultural factors in the selection of sites for the land disposal of wastes in Washington

As part of a program to deal with the problems of waste disposal in Washington, the Department of Ecology (WDOE), in cooperation with the U.S. Geological Survey, completed a study designed to provide the geologic, hydrologic, and cultural data needed to evaluate the suitability of State land areas for the disposal of wastes. Data portraying the distribution of factors that could affect the suitability of areas in Washington for waste disposal were presented in a series of 18 maps (overlays). The factors selected include major geologic units; natural hazards from earthquakes, faulting, and volcanoes; climate; locations of major surface-water and groundwater bodies; population density; and land and water uses. Within each factor (map) the data were grouped into class intervals and the intervals for most factors ranked according to their relative suitability/unsuitability for land disposal of wastes following criteria supplied by WDOE. Areas of the State considered completely unsuitable (as determined by WDOE personnel) for waste disposal because of current or proposed land uses were excluded from ranking. (USGS)

Water-Resources Investigations Report↗
USGS1987

Hydrologic and geologic factors affecting land subsidence near Eloy, Arizona

At an extensometer site near Eloy, Arizona, 1.09 m of land subsidence caused by groundwater withdrawal were measured by leveling in 1965-83. The extensometer, which partially penetrates the compressible sediments, recorded 0.82 m of compaction during the same period. By use of a one-dimensional model, cumulative daily compaction values were simulated to within an average of 0.0038 m of the actual values. Land subsidence was simulated to within an average of 0.011 m using the same model in conjunction with geohydrologic data of the sediments below the extensometer. A highly compressible clay layer that is 24.38 m thick was partially penetrated by the extensometer. The simulation indicated that the layer was driving compaction and land subsidence linearly with respect to time, despite the presence of other compacting layers. Because of its thickness and compressibility, this layer can be expected to continue to compact after applied vertical stresses have stopped increasing and other layers have stopped compacting. Sensitivity analysis indicated that the compressibility of fine-grained sediments (expressed as specific storage) is one of the factors to which compact is most sensitive. Preconsolidation stress and hydraulic conductivity also affect land subsidence near Eloy, Arizona. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1994

Hydrogeology, herbicides and nutrients in ground water and springs, and relation of water quality to land use and agricultural practices near Carlisle, Pennsylvania

Discharge and water-quality data collected in two adjacent karst-spring basins in Cumberland County, Pa., from May 1990 through April 1991 were used to (1) describe the hydrogeology of the area; (2) determine the concentrations of selected herbicides, herbicide-soil metabolites, and nutrients in water from wells and discharges from springs, (3) determine herbicide and nutrient discharges from springs; and (4) determine the relation of ground-water quality to land use and agricultural practices in the spring basins. The study area is underlain by a regolith-mantled carbonate-rock aquifer system. Agricultural land, forest, and residential land are the principal land uses. Herbicides are applied primarily to cornfields. Cyanazine, atrazine, metolachlor, and alachlor account for about 90 percent of the documented herbicide use on cropland. Daily mean discharge of Alexanders and Mount Rock Springs was 3.8 and 3.7 cubic feet per second, and total discharge was 1,390 and 1,370 cubic feet per second-days. Increases in discharge were related to individual periods of precipitation, but maximum flow rates lagged precipitation periods by 2 to 5 days. The recharge area to each spring is estimated to be 2.8 square miles. Atrazine was the only herbicide in common use that was detected in discharges from springs. Atrazine and the atrazine soil-metabolite deethylatrazine (DEA) were detected in spring discharges for the duration of the study. Changes in atrazine and DEA concentrations in the discharges from springs were minimal, and no flush of herbicides from the springs followed application. Temporal variation in constituent discharges was related mostly to changes in spring flow; the largest daily constituent discharges coincided with periods of increased spring flow during the winter and early spring. Atrazine and DEA discharged from Alexanders Spring and Mount Rock Spring were about 0.5 and 0.6 percent of the estimated annual atrazine use on row crops in their respective recharge areas.

Water-Resources Investigations Report↗
USGS1995

Relation of land use to nitrogen concentration in ground water in the Patuxent River basin, Maryland

A decrease in nitrogen inputs could improve water quality in the Chesapeake Bay. In order to provide information about nitrogen transport to the bay, the U.S. Geological Survey examined historical land use associated with nonpoint sources of nitrogen and nitrogen concentrations in ground water in the Patuxent River Basin, Maryland; The Patuxent River is a major tributary to the bay. Most nitrogen in ground water was present as nitrate. In the Piedmont Physiographic Province part of the Patuxent River basin, nitrate concentrations in ground water were higher in agricultural areas than in forested and urban areas. Nitrate concentrations were related to land use at well sites because wells yielded water that infiltrated within the same contributing area where the wells are located. Agricultural activities possibly were a source for the transport of large amounts of nitrogen to ground water and probably also to base flow in nearby streams. The high nitrate concentrations were not attributed to sampling bias. In the Coastal Plain Physiographic Province, most nitrate concentrations were low and were unrelated to land use at the well site because the wells were screened in deep, regional aquifers. Ground water in a few shallow wells had high nitrate concentrations, possibly related to nearby agricultural and urban land use. Increased nitrate concentrations in shallow ground water could increase concentrations in stream base flow and eventually could increase concentrations in regional aquifers and ground water that discharges directly to the Chesapeake Bay.

Water-Resources Investigations Report↗
USGS1995

Relation of nitrate concentrations in ground water to well depth, well use, and land use in Franklin Township, Gloucester County, New Jersey, 1970-85

A water-quality data base was developed to permit the investigation of the relation of concentrations of nitrate (as nitrogen) in ground water to well depth, well use, and land use (agricultural, residential, urban nonresidential, and undeveloped) in Franklin Township. Nitrate concentrations in water from 868 wells tended to decrease with depth. A rank-order regression model of nitrate concen- trations and land-use percentages was fitted to data from 98 shallow domestic wells. The model, which explains about 25 percent of the variance in the data, indicated that nitrate concentration increased with the percentage of developed land in a well's buffer zone. Further stratification of the data based on well use (commercial, domestic, or agricultural/irrigation) indicated that elevated nitrate concentrations were more common in water from agricultural/irrigation wells than in water from domestic or commercial wells. Concentrations of nitrate were indicative of human activities in water from about one-third of the wells sampled but exceeded the U.S. Environmental Protection Agency's maximum contaminant level of 10 milligrams per liter in water from only 1 percent of the wells. A sampling strategy in which water from wells of different depths located within areas in each of the four land-use categories is sampled yearly and analyzed for nitrate and other constituents would facilitate determination of the effects of human activities on ground-water quality.

New Jersey↗
USGS1995

Land use and water use in the Antelope Valley, California

Urban land use and water use in the Antelope Valley, California, have increased significantly since development of the valley began in the late 1800's.. Ground water has been a major source of water in this area because of limited local surface-water resources. Ground-water pumpage is reported to have increased from about 29,000 acre-feet in 1919 to about 400,000 acre-feet in the 1950's. Completion of the California Aqueduct to this area in the early 1970's conveyed water from the Sacramento-San Joaquin Delta, about 400 miles to the north. Declines in groundwater levels and increased costs of electrical power in the 1970's resulted in a reduction in the quantity of ground water that was pumped annually for irrigation uses. Total annual reported ground-water pumpage decreased to a low of about 53,200 acre-feet in 1983 and increased to about 91,700 acre-feet in 1991 as a result of rapid urban development and the 1987-92 drought. This increased urban development, in combination with several years of drought, renewed concern about a possible return to extensive depletion of ground-water storage and increased land subsidence. Increased water demands are expected to continue as a result of increased urban development. Water-demand forecasts in 1980 for the Antelope Valley indicated that total annual water demand by 2020 was expected to be about 250,000 acre-feet, with agricultural demand being about 65 percent of this total. In 1990, total water demand was projected to be about 175,000 acre-feet by 2010; however, agricultural water demand was expected to account for only 37 percent of the total demand. New and existing land- and water-use data were collected and compiled during 1992-93 to identify present and historical land and water uses. In 1993, preliminary forecasts for total water demand by 2010 ranged from about 127,500 to 329,000 acre-feet. These wide-ranging estimates indicate that forecasts can change with time as factors that affect water demand change and different forecasting methods are used. The forecasts using the MWD_MAIN (Metropolitan Water District of Southern California Municipal and Industrial Needs) water-demand forecasting system yielded the largest estimates of water demand. These forecasts were based on projections of population growth and other socioeconomic variables. Initial forecasts using the MWD_MAIN forecasting system commonly are considered "interim" or preliminary. Available historical and future socioeconomic data required for the forecasting system are limited for this area. Decisions on local water-resources demand management may be made by members of the Antelope Valley Water Group and other interested parties based on this report, other studies, their best judgement, and cumulative knowledge of local conditions. Potential water-resource management actions in the Antelope Valley include (1) increasing artificial ground-water recharge when excess local runoff (or imported water supplies) are available; (2) implementing water-conservation best-management practices; and (3) optimizing ground-water pumpage throughout the basin.

Water-Resources Investigations Report↗
USGS1996

Variations in land use and nonpoint-source contamination on the Fort Berthold Indian Reservation, west-central North Dakota, 1990-93

The effects of land-use activities on the water quality of five streams on the Fort Berthold Indian Reservation were evaluated. The five basinsevaluated were East Fork Shell Creek, Deepwater Creek, Bear Den Creek, Moccasin Creek, and Squaw Creek. East Fork Shell Creek and DeepwaterCreek Basins are located east of Lake Sakakawea and Bear Den Creek, Moccasin Creek, and Squaw Creek Basins are located west of the lake. Land-use data for the five selected basins on and adjacent to the Fort Berthold Indian Reservation were obtained for 1990-92. Discharge measurements were made and water-quality samples were collected at stations and sites on each of the five streams during October 1991 through September 1993. Analysis of land-use data indicated that prairie was the largest land-use category in the study area. More prairie acreage was found in the basins located west of Lake Sakakawea than in the basins located east of the lake. Wheat was the predominant crop in the study area. More wheat acreage was found in the basins located east of Lake Sakakawea than in the basins located west of the lake. Discharge data for the five selected streams indicated that all of thestreams were ephemeral and had many days of no flow during the study period. High flows were usually the result of spring runoff or intense storms over the basins. East Fork Shell Creek and Deepwater Creek with larger basins and flatter stream slopes had high flows characterized by rapidly rising flows and gradually receding flows. In contrast, Bear DenCreek, Moccasin Creek, and Squaw Creek with smaller basins and steeper stream slopes had high flows characterized by rapidly rising flows and receding flows of shorter duration. Analysis of water-quality samples indicated concentrations of nitrogen, phosphorus, and total organic carbon varied throughout the study area. Nitrogen concentrations were larger in the streams located east of LakeSakakawea than in the streams located west of the lake. The largest nitrogen concentrations in all of the streams occurred during the nongrowing periods.Phosphorus (orthophosphate and total phosphorus)concentrations were larger in the streams located east of Lake Sakakawea than in the streams located west of the lake. The larger orthophosphateconcentrations in the eastern streams may be indicative of insecticide application in the eastern streams' basins. Total organic carbon concentrations were fairly consistent in all five streams. Water-quality samples were analyzed for the pesticides atrazine, carbofuran, cyanazine, and 2,4-D by using immunoassay testing. Pesticide concentrations above the minimum reporting levels were more prevalent insamples from streams located east of Lake Sakakawea than in the streams located west of the lake. The eastern streams drain areas where herbicides were applied to crops. Fecal-bacteria concentrations were larger in the streams located west of Lake Sakakawea, where prairie is more dominant, than in the streams located east of the lake. The larger concentrations and loads were associated with intense storm events and the presence of livestock.

Water-Resources Investigations Report↗
USGS1997

Ground-water age dating and other tools used to assess land-use effects on water quality

A relatively new method for age dating recent ground water along with other investigative tools improve our understanding of land-use effects on the water quality in a surficial aquifer and adjacent streams in the Red River of the North Basin: Ground water commonly takes more than 20 years to reach depths in the surficial aquifer where it is withdrawn for use. Water withdrawn from most drinking-water wells was recharged through land areas greater than 1 mile upgradient. Because of these long travel times and distances, land-management practices on the land and aquifer-protection strategies may take as much as 50 years to produce measurable improvement in water quality. The amount of fertilizer and some herbicides used to enhance crop growth in this study area can be related to the distribution and trends of nitrate and herbicides found in the surficial aquifer.

Red River of the North Basin↗
USGS2000

Effects of land use and hydrogeology on the water quality of alluvial aquifers in eastern Iowa and southern Minnesota, 1997

Ground-water samples were collected from monitoring wells at 31 agricultural and 30 urban sites in the Eastern Iowa Basins study unit during June–August 1997 to evaluate the effects of land use and hydrogeology on the water quality of alluvial aquifers. Ground-water samples were analyzed for common ions, nutrients, dissolved organic carbon, tritium, radon-222, pesticides and pesticide metabolites, volatile organic compounds, and environmental isotopes. Calcium, magnesium, and bicarbonate were the dominant ions in most samples and were likely derived from solution of carbonate minerals (calcite and dolomite) present in alluvial detrital deposits. Chloride and nitrate were dominant anions in samples from several wells. Sodium and chloride concentrations were significantly higher in samples from urban areas, where roads are more numerous and road salts may be more frequently applied, than in agricultural areas. Nitrate was detected in 94 percent of samples from agricultural areas and 77 percent of samples from urban areas. Nitrate concentrations were significantly higher in agricultural areas than in urban areas and exceeded the U.S. Environmental Protection Agency maximum ontaminant level for drinking water (10 milligrams per liter as N) in 39 percent of samples from agricultural areas. Nitrate concentrations in samples from urban areas did not exceed the maximum contaminant level. Greater use of fertilizers in agricultural areas most likely contributes to higher nitrate concentrations in samples from those areas. Tritium-based ages indicate ground water was most likely recharged after the 1950’s at all but one sampling site. Agricultural and urban land-use areas have remained relatively stable in the study area since the 1950’s; therefore, the effects of current land use should be reflected in ground water sampled during this study. Radon-222 was detected in all samples and exceeded the U.S. Environmental Protection Agency’s previously proposed maximum contaminant level for drinking water (300 picocuries per liter) in 71 percent of samples. Pesticides were detected in 84 percent of samples from agricultural areas and 70 percent from urban areas. Atrazine and metolachlor were the most frequently detected pesticides in samples from agricultural areas; atrazine and prometon were the most frequently detected pesticides in samples from urban areas. None of the pesticide oncentrations exceeded U.S. Environmental Protection Agency maximum contaminant levels or lifetime health advisories for drinking water. Pesticide metabolites were detected in 94 percent of samples from agricultural areas and 53 percent from urban areas. Metolachlor ethane sulfonic acid and deethylatrazine were the most frequently detected metabolites in samples from agricultural areas; metolachlor ethane sulfonic acid and alachlor ethane sulfonic acid were the most frequently detected metabolites in samples from urban areas. Total metabolite concentrations were significantly higher in samples from agricultural areas than in samples from urban areas. Total pesticide concentrations (parent compounds) tended to be higher in samples from agricultural areas; however, this difference was not statistically significant. Metabolites constituted the major portion of the total residue concentration in the alluvial aquifer. Volatile organic compounds were detected in 40 percent of samples from urban areas and 10 percent from agricultural areas. Methyl tertbutyl ether was the most commonly detected volatile organic compound and was present in 23 percent of samples from urban areas. Elevated concentrations (greater than 30 micrograms per liter) of methyl tert-butyl ether and BTEX compounds (benzene, toluene, ethylbenzene, and xylene) in two samples from urban areas suggest the possible presence of point-source gasoline leaks or spills. Factors other than land use may contribute to observed differences in water quality between and within agricultural and urban areas. Nitrate, atrazine, deethylatrazine, and deisopropylatrazine concentrations were significantly higher in shallow wells with sample intervals nearer the water table and in wells with thinner cumulative clay thickness above the sample intervals. These relations suggest that longer flow paths allow for greater residence time and increase opportunities for sorption, degradation, and dispersion, which may contribute to decreases in nutrient and pesticide concentrations with depth. Nitrogen speciation was influenced by redox conditions. Nitrate concentrations were significantly higher in ground water with dissolved-oxygen concentrations in excess of 0.5 milligram per liter. Ammonia concentrations were higher in ground water with dissolved-oxygen concentrations of 0.5 milligram per liter or less; however, this relation was not statistically significant. The amount of available organic matter may limit denitrification rates. Elevated nitrate concentrations (greater than 2.0 mg/L) were significantly related to lower dissolved organic carbon concentrations in water samples from both agricultural and urban areas. A similar relation between nitrate concentrations (in water) and organic carbon concentrations (in aquifer material) also was observed but was not statistically significant.

Iowa, Minnesota↗
USGS1966

Hydrology of Cornfield Wash area and effects of land-treatment practices, Sandoval County, New Mexico, 1951-60

The collection of runoff and sediment data was the primary objective of the 10-year (1951-60) study in the Cornfield Wash basin, which has an area of 21.3 square miles. However, reconnaissance investigations also were made of (1) precipitation; (2) the effects of reservoirs on runoff, erosion, and sediment yield; (3) the effects of range pitting on runoff, sediment, and vegetation yields; and (4) the effects of wire sediment barriers on sediment accumulations. Precipitation averaged 6.07 inches for the warm season (May 1 through October 31). From 1951 to 1955 much of the precipitation came in short torrential downpours. Since 1955, precipitation usually has been of lower intensity, resulting in a low runoff-precipitation ratio. The total composite inflow to the 19 reservoirs in the Cornfield Wash basin--12 constructed in 1950 and 7 constructed from 1953 to 1956--was 5,720 acre-feet. The reservoirs permanently retained 1,370 acre-feet of water, 43 percent of which was apparently lost by evaporation. The average seasonal runoff (1951-59) from the ephemeral streams of the Cornfield Wash basin and nearby watersheds can be expressed, with a high coefficient of correlation, by the equation: runoff = 29.4 (area) 0.82 acre-feet. This relation suggests that there is a good correlation between the size of the drainage basin and the basin characteristics that most influence travel time of runoff. Comparisons of readily measurable basin characteristics that influence travel time indicate: 1. Land slope is proportional to (area) .0.035; 2. Length of longest watercourse is proportional to (area) 0.52; 3. Distance along the longest watercourse from gaging station to a point opposite the center of drainage basin is proportional to (area)0.52; and 4. Equivalent channel slope is proportional to (area)- 0.027. Except for land slope, the coefficients of correlation for each of the basin characteristics-area relations were relatively high. The correlation between seasonal runoff (1951-60) from the small watersheds of the Cornfield Wash basin and the size of the drainage basin was improved after correcting for the influence of land slope. The original total storage capacity of the 19 reservoirs was reduced from 845 to 455 acre-feet as a result of the impoundment of 390 acre-feet of sediment. Backwater from the reservoirs influenced the deposition of an additional 20 acre-feet of sediment. The average annual accretion of sediment (1951-60) in the reservoirs of the Cornfield Wash basin can be expressed by the equation: sediment - 0.0119 (seasonal runoff) 1.3 (incised channel density) 0.71. By removing seasonal runoff as a variable, the average annual sediment accretion is proportional to (area) 1.19 (incised channel density) 1.3. Conservation and rehabilitation of damaged land were successful in some instances and only partly successful in others. The reservoirs are effective in inducing sediment accretion upstream; also, they stop the advance of abrupt headcuts below the reservoirs, but only as long as the spillage is not great and the spillway stays intact. In addition, the reservoirs are effective in reducing flood peaks. A longer period of study is necessary to define adequately the effectiveness of the wire sediment barriers. The data collected on range-pitting effects were not complete enough to. define the magnitude of the changes, if any, in runoff, sediment, and vegetation yields.

New Mexico↗
USGS2017

Forest harvest patterns on private lands in the Cascade Mountains, Washington, USA

Forests in Washington State generate substantial economic revenue from commercial timber harvesting on private lands. To investigate the rates, causes, and spatial and temporal patterns of forest harvest on private tracts throughout the Cascade Mountains, we relied on a new generation of annual land-use/land-cover (LULC) products created from the application of the Continuous Change Detection and Classification (CCDC) algorithm to Landsat satellite imagery collected from 1985 to 2014. We calculated metrics of landscape pattern using patches of intact and harvested forest in each annual layer to identify changes throughout the time series. Patch dynamics revealed four distinct eras of logging trends that align with prevailing regulations and economic conditions. We used multiple logistic regression to determine the biophysical and anthropogenic factors that influence fine-scale selection of harvest stands in each time period. Results show that private lands forest cover became significantly reduced and more fragmented from 1985 to 2014. Variables linked to parameters of site conditions, location, climate, and vegetation greenness consistently distinguished harvest selection for each distinct era. This study demonstrates the utility of annual LULC data for investigating the underlying factors that influence land cover change.

Washington↗
USGS2023

Random forest classification of multitemporal Landsat 8 spectral data and phenology metrics for land cover mapping in the Sonoran and Mojave Deserts

Geospatial data and tools evolve as new technologies are developed and landscape change occurs over time. As a result, these data may become outdated and inadequate for supporting critical habitat-related work across the international boundary in the Sonoran and Mojave Deserts Bird Conservation Region (BCR 33) due to the area’s complex vegetation communities and the discontinuity in data availability across the United States (US) and Mexico (MX) border. This research aimed to produce the first 30 m continuous land cover map of BCR 33 by prototyping new methods for desert vegetation classification using the Random Forest (RF) machine learning (ML) method. The developed RF classification model utilized multitemporal Landsat 8 Operational Land Imager spectral and vegetation index data from the period of 2013–2020, and phenology metrics tailored to capture the unique growing seasons of desert vegetation. Our RF model achieved an overall classification F-score of 0.80 and an overall accuracy of 91.68%. Our results portrayed the vegetation cover at a much finer resolution than existing land cover maps from the US and MX portions of the study area, allowing for the separation and identification of smaller habitat pockets, including riparian communities, which are critically important for desert wildlife and are often misclassified or nonexistent in current maps. This early prototyping effort serves as a proof of concept for the ML and data fusion methods that will be used to generate the final high-resolution land cover map of the entire BCR 33 region.

Remote Sensing↗
USGS2025

RUSH: Rapid remote sensing Updates of land cover for Storm and Hurricane forecast models

Coastal vegetated ecosystems, including tidal marshes, vegetated dunes, and shrub- and forest-dominated wetlands, can mitigate hurricane impacts such as coastal flooding and erosion by increasing surface roughness and reducing wave energy. Land cover maps can be used as input to improve simulations of surface roughness in advanced hydro-morphological models. Consequently, there is a need for efficient tools to develop up-to-date land cover maps that include the accurate distribution of vegetation types prior to an extreme storm. In response, we developed the RUSH tool (Rapid remote sensing Updates of land cover for Storm and Hurricane forecast models). RUSH delivers high-resolution maps of coastal vegetation for near-real-time or historical conditions via a Jupyter Notebook application and a graphical user interface (GUI). The application generates 3 m spatial resolution land cover maps with classes relevant to coastal settings, especially along mainland beaches, headlands, and barrier islands, as follows: (1) open water; (2) emergent wetlands; (3) dune grass; (4) woody wetlands; and (5) bare ground. These maps are developed by applying one of two seasonal random-forest machine learning models to Planet Labs SuperDove multispectral imagery. Cool Season and Warm Season Models were trained on 665 and 594 reference points, respectively, located across study regions in the North Carolina Outer Banks, the Mississippi Delta in Louisiana, and a portion of the Florida Gulf Coast near Apalachicola. Cool Season and Warm Season Models were tested with 666 and 595 independent points, with an overall accuracy of 93% and 94%, respectively. The Jupyter Notebook application provides users with a flexible platform for customization for advanced users, whereas the GUI, designed with user-experience feedback, provides non-experts access to remote sensing capabilities. This application can also be used for long-term coastal geomorphic and ecosystem change assessments.

Florida, Louisiana, North Carolina↗
USGS2010

Detecting Ecosystem Performance Anomalies for Land Management in the Upper Colorado River Basin Using Satellite Observations, Climate Data, and Ecosystem Models

This study identifies areas with ecosystem performance anomalies (EPA) within the Upper Colorado River Basin (UCRB) during 2005–2007 using satellite observations, climate data, and ecosystem models. The final EPA maps with 250-m spatial resolution were categorized as normal performance, underperformance, and overperformance (observed performance relative to weather-based predictions) at the 90% level of confidence. The EPA maps were validated using “percentage of bare soil” ground observations. The validation results at locations with comparable site potential showed that regions identified as persistently underperforming (overperforming) tended to have a higher (lower) percentage of bare soil, suggesting that our preliminary EPA maps are reliable and agree with ground-based observations. The 3-year (2005–2007) persistent EPA map from this study provides the first quantitative evaluation of ecosystem performance anomalies within the UCRB and will help the Bureau of Land Management (BLM) identify potentially degraded lands. Results from this study can be used as a prototype by BLM and other land managers for making optimal land management decisions.

Remote Sensing↗
USGS2023

National Land Cover Database 2019: A new strategy for creating clean leaf-on and leaf-off Landsat composite images

National Land Cover Database (NLCD) 2019 is a new epoch of national land cover products for the conterminous United States. Image quality is fundamental to the quality of any land cover product. Image preprocessing has often taken a considerable proportion of overall time and effort for this kind of national project. An approach to prepare image inputs for NLCD 2019 production was developed to ensure efficiency and quality of operational production. Here, we introduce a new and comprehensive strategy to produce clear Landsat composite images for NLCD 2019 production. First, we developed a new median-value compositing method. Second, we designed parameter settings for selecting images and pixels to generate 4 composite images (leaf-on, leaf-off, primary reference, and complementary reference) for a target year based on the US Landsat Analysis Ready Data surface reflectance dataset. Third, we developed a method, referred to as Detection and Filling with Simulated Image, to detect and replace clouds and cloud shadow pixels to produce the final clean leaf-on and leaf-off image composites. This image compositing and processing strategy was implemented for the entire conterminous United States to produce images for NLCD 2019. Our image results and NLCD 2019 change detection and land cover products, which were released in July 2021, showed this new strategy to be effective and efficient.

ISPRS Journal of Photogrammetry and Remote Sensing↗
USGS2015

Assessment of model estimates of land-atmosphere CO 2 exchange across northern Eurasia

A warming climate is altering land-atmosphere exchanges of carbon, with a potential for increased vegetation productivity as well as the mobilization of permafrost soil carbon stores. Here we investigate land-atmosphere carbon dioxide (CO 2 ) cycling through analysis of net ecosystem productivity (NEP) and its component fluxes of gross primary productivity (GPP) and ecosystem respiration (ER) and soil carbon residence time, simulated by a set of land surface models (LSMs) over a region spanning the drainage basin of Northern Eurasia. The retrospective simulations cover the period 1960–2009 at 0.5° resolution, which is a scale common among many global carbon and climate model simulations. Model performance benchmarks were drawn from comparisons against both observed CO 2 fluxes derived from site-based eddy covariance measurements as well as regional-scale GPP estimates based on satellite remote-sensing data. The site-based comparisons depict a tendency for overestimates in GPP and ER for several of the models, particularly at the two sites to the south. For several models the spatial pattern in GPP explains less than half the variance in the MODIS MOD17 GPP product. Across the models NEP increases by as little as 0.01 to as much as 0.79 g C m −2 yr −2 , equivalent to 3 to 340 % of the respective model means, over the analysis period. For the multimodel average the increase is 135 % of the mean from the first to last 10 years of record (1960–1969 vs. 2000–2009), with a weakening CO 2 sink over the latter decades. Vegetation net primary productivity increased by 8 to 30 % from the first to last 10 years, contributing to soil carbon storage gains. The range in regional mean NEP among the group is twice the multimodel mean, indicative of the uncertainty in CO 2 sink strength. The models simulate that inputs to the soil carbon pool exceeded losses, resulting in a net soil carbon gain amid a decrease in residence time. Our analysis points to improvements in model elements controlling vegetation productivity and soil respiration as being needed for reducing uncertainty in land-atmosphere CO 2 exchange. These advances will require collection of new field data on vegetation and soil dynamics, the development of benchmarking data sets from measurements and remote-sensing observations, and investments in future model development and intercomparison studies.

Biogeosciences↗