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USGS2020

Not all fuel‐reduction treatments degrade biocrusts: Herbicides cause mostly neutral to positive effects on cover of biocrusts

In response to increasing fire, fuel‐reduction treatments are being used to minimize large fire risk. Although biocrusts are associated with reduced cover of fire‐promoting, invasive grasses, the impact of fuel‐reduction treatments on biocrusts is poorly understood. We use data from a long‐term experiment, the Sagebrush Steppe Treatment Evaluation Project, testing the following fuel‐reduction treatments: mowing, prescribed fire, and the use of two herbicides: one commonly used to reduce shrub cover, tebuthiuron, and one commonly used to combat cheatgrass, imazapic. Looking at sites with high cover of biocrusts prior to treatments, we demonstrate positive effects of the herbicide, tebuthiuron on lichens with an increase in cover of 10% and trending towards slightly negative effects on moss cover. Across plots, imazapic trended towards a decrease in lichen and moss cover without being statistically significant. Mowing and prescribed fire reduced cover of mosses, with the latter leading to greater declines across sites (declines of 18% vs. 32%). Reductions in moss cover mirrored gains in cover of bare soil, which is associated with increased risk of invasion by grasses responsible for increasing fire risk. We demonstrate that the use of herbicides simultaneously reduces fuels and maintains greater cover of lichens and mosses compared with other fuel‐reduction treatments, possibly reducing risk of invasion by annual grasses that are responsible for increasing fire risk.

Land Degradation & Development↗

USGS2011

Multilevel regression models describing regional patterns of invertebrate and algal responses to urbanization across the USA

Multilevel hierarchical regression was used to examine regional patterns in the responses of benthic macroinvertebrates and algae to urbanization across 9 metropolitan areas of the conterminous USA. Linear regressions established that responses (intercepts and slopes) to urbanization of invertebrates and algae varied among metropolitan areas. Multilevel hierarchical regression models were able to explain these differences on the basis of region-scale predictors. Regional differences in the type of land cover (agriculture or forest) being converted to urban and climatic factors (precipitation and air temperature) accounted for the differences in the response of macroinvertebrates to urbanization based on ordination scores, total richness, Ephemeroptera, Plecoptera, Trichoptera richness, and average tolerance. Regional differences in climate and antecedent agriculture also accounted for differences in the responses of salt-tolerant diatoms, but differences in the responses of other diatom metrics (% eutraphenic, % sensitive, and % silt tolerant) were best explained by regional differences in soils (mean % clay soils). The effects of urbanization were most readily detected in regions where forest lands were being converted to urban land because agricultural development significantly degraded assemblages before urbanization and made detection of urban effects difficult. The effects of climatic factors (temperature, precipitation) on background conditions (biogeographic differences) and rates of response to urbanization were most apparent after accounting for the effects of agricultural development. The effects of climate and land cover on responses to urbanization provide strong evidence that monitoring, mitigation, and restoration efforts must be tailored for specific regions and that attainment goals (background conditions) may not be possible in regions with high levels of prior disturbance (e.g., agricultural development).

Journal of the North American Benthological Societ↗

USGS2023

Time, climate, and soil settings set the course for reclamation outcomes following dryland energy development

Soil attributes, climate, and time since reclamation have important implications for oil and gas reclamation success on drylands. It is uncertain if reclaimed well pads, on highly degraded drylands, can successfully regain ecological function or meet indicator benchmarks for reclamation. Here, our goals were to assess patterns in reclamation outcomes relative to (1) soil attributes, climate, and time since reclamation; and (2) plant and soil reference benchmarks. We collected a suite of plant, soil, and landscape characteristics from 134 reclaimed well pads on the Colorado Plateau that spanned climate and soil gradients and ranged from 2 to 20 years post-reclamation, then compared characteristics to those from 583 reference plots. On the reclaimed pads, less saline soils, more mesic climates, and longer time since reclamation were associated with favorable reclamation outcomes based on metrics of plant species richness and diversity, plant structure, and cover of important plant functional groups. However, most pads had major departures in 1/4 indicators, suggesting unsuccessful reclamation. Arid warm locations with shallow soils had the greatest percentage of major departures, and noxious plant richness had the greatest departures across soil and climate settings. Our assessment indicates reclamation is failing in key metrics for most pads, and the results highlight the role of environmental conditions in driving reclamation outcomes. These new insights are valuable for ascertaining possible reclamation outcomes and success rates following energy related disturbance, including orphaned wells and renewable energy development. Importantly, the approach used here has applicability for setting benchmarks and outcome standards.

Land Degradation and Development↗

USGS2004

Rehabilitation of a lignite mine-disturbed area in the Indian Desert

Extensive lignite mining in the Indian (Thar) Desert commenced within the past decade. Accompanying extraction of this valuable resource there have been visible, important environmental impacts. The resultant land degradation has prompted concern from both public and regulatory bodies. This research assesses the success of rehabilitation plans implemented to revegetate a lignite mine-disturbed area, near the village of Giral in western Rajasthan State. Rehabilitation success was achieved within the environmental constraints of this northwest Indian hot-desert ecosystem using a combination of: (1) backfilling (abandoned pits) with minespoil and of covering the backfilled-surfaces with fresh topsoil to a thickness of about 0??30 m; (2) use of micro-catchment rainwater harvesting (MCWH) technique; (3) soil profile modification approaches; (4) plant establishment methodologies; and (5) the selection of appropriate germplasm material (trees, shrubs and grasses). Preliminary results indicate that the resulting vegetative cover will be capable of self-perpetuation under natural conditions while at the same time meeting the land-use requirements of the local people. The minespoil is alkaline in nature and has high electrical conductance. The average content of organic carbon, N, P and K is lower than in the regional topsoil. However, the concentration of Ca, Mg, Na and total S in the minespoil is much higher than in the topsoil. Further, the spoil material has no biological activity. Enhanced plant growth was achieved in MCWH plots, compared to control plots, where minespoil moisture storage was improved by 18-43 per cent. The rehabilitation protocol used at the site appears to have been successful because, in addition to the planted species, desirable native invasive species have become established. This study developed methods for the rehabilitation of lignite mine-disturbed areas and has also resulted in an understanding of rehabilitation processes in arid regions with an emphasis on the long-term monitoring of rehabilitation success. ?? 2004 John Wiley and Sons, Ltd.

Land Degradation and Development↗

USGS2000

Rehabilitation of lands mined for limestone in the Indian desert

In the Indian desert, the economics of mining is second only to agriculture in importance. However, research on the rehabilitation of land disturbed by mining has only recently received serious attention. An attempt has been made to determine both the qualitative and quantitative success of rehabilitation plans used to revegetate limestone mine spoils in an area near Barna, northwest arid India. Rehabilitation success was achieved using a combination of rainwater harvesting techniques, soil amendment application approaches, plant establishment methods and the selection of appropriate germplasm material (trees, shrubs and grasses). It is expected that the resulting vegetative cover will be capable of self-perpetuation under natural conditions while at the same time meeting the land-use needs of the local people. The minespoils have adequate levels of the major nutrients (except P, Mo and Se) for proper plant and grazing animal health. Levels of organic matter are low whereas total B concentrations are exceptionally high. Also, the population of soil fungi, Azotobactor, and nitrifying bacteria is negligible. Enhanced plant growth was achieved in treated plots, compared to control plots, where spoil moisture storage was improved by 5-45 per cent. Due to the decomposition of farmyard manure and nitrogen fixation by planted leguminous plant species, the electrical conductance of treated mine spoils increased threefold, CaCO3 content decreased from 20??0 to 5??2 per cent, and organic carbon, P, K, and biological activity increased significantly. The rehabilitation protocol used at the site appears to have been successful because plant self-regeneration is occurring. The increased diversity of woody perennials resulted in 'dominance' being better shared among species and 'evenness' being increased within the plant community elements. The early to mid-successional trends are continuing for six years following initial rehabilitation. This study developed methods for the rehabilitation of lands mined for limestone and has also resulted in an understanding of rehabilitation processes in arid regions with an emphasis on the long-term monitoring of rehabilitation success. Copyright ?? 2000 John Wiley & Sons, Ltd.

Land Degradation and Development↗

USGS2022

Geologic, geomorphic, and edaphic underpinnings of dryland ecosystems: Colorado Plateau landscapes in a changing world

Drylands represent more than 41% of the global land surface and are at degradation risk due to land use and climate change. Developing strategies to mitigate degradation and restore drylands in the face of these threats requires an understanding of how drylands are shaped by not only soils and climate, but also geology and geomorphology. However, few studies have completed such a comprehensive analysis that relates spatial variation in plant communities to all aspects of the geologic–geomorphic–edaphic–plant–climate system. The focus of this study is the Colorado Plateau, a high-elevation dryland in the southwestern United States, which is particularly sensitive to future change due to climate vulnerability and increasing land-use pressure. Here, we examined 135 long-term vegetation-monitoring sites in three national parks and characterized connections between geology, geomorphology, soils, climate, and dryland plant communities. To first understand the geologic and geomorphic influences on soil formation and characteristics, we explore associations between soil pedons, bedrock geology, and geomorphology. Then, we characterize principal axes of variation in plant communities and ascertain controls and linkages between components of the edaphic–geomorphic system and plant community ordinations. Geologic and geomorphic substrate exerted controls on important properties of the soil profile, particularly depth, water-holding capacity, rockiness, salinity, and fine sands. Ordination identified five distinct plant communities and three primary axes of variation, representing gradients of woody- to herbaceous-dominated communities (Axis 1), saline scrublands to C 3 grasslands (Axis 2), and annual to perennial communities (Axis 3). Geology, geomorphology, and soil explained a large proportion of variation in Axis 1 (74%), while climate variables largely explained Axis 2 (68%), and Axis 3 was not well explained by the random forest models. The variables identified as most influential to each axis were, respectively: (1) soil depth; (2) aridity, lithology, and soil salinity; and (3) temperature and precipitation. We posit that Axis 3 represents a land degradation gradient due to historic grazing, likely exacerbated by dry conditions. Results provide a novel framework that links the geologic and geomorphic evolution of landscapes, with the distribution of soils and plant communities that can guide ecosystem management, exemplifying an approach applicable to drylands globally.

Arizona, Colorado, New Mexico, Utah↗

USGS2015

Mapping extent and change in surface mines within the United States for 2001 to 2006

A complete, spatially explicit dataset illustrating the 21st century mining footprint for the conterminous United States does not exist. To address this need, we developed a semi-automated procedure to map the country's mining footprint (30-m pixel) and establish a baseline to monitor changes in mine extent over time. The process uses mine seed points derived from the U.S. Energy Information Administration (EIA), U.S. Geological Survey (USGS) Mineral Resources Data System (MRDS), and USGS National Land Cover Dataset (NLCD) and recodes patches of barren land that meet a “distance to seed” requirement and a patch area requirement before mapping a pixel as mining. Seed points derived from EIA coal points, an edited MRDS point file, and 1992 NLCD mine points were used in three separate efforts using different distance and patch area parameters for each. The three products were then merged to create a 2001 map of moderate-to-large mines in the United States, which was subsequently manually edited to reduce omission and commission errors. This process was replicated using NLCD 2006 barren pixels as a base layer to create a 2006 mine map and a 2001–2006 mine change map focusing on areas with surface mine expansion. In 2001, 8,324 km 2 of surface mines were mapped. The footprint increased to 9,181 km 2 in 2006, representing a 10·3% increase over 5 years. These methods exhibit merit as a timely approach to generate wall-to-wall, spatially explicit maps representing the recent extent of a wide range of surface mining activities across the country.

Land Degradation and Development↗

USGS2014

Modelling landscape-scale erosion potential related to vehicle disturbances along the U.S.-Mexico border

Decades of intensive off-road vehicle use for border security, immigration, smuggling, recreation, and military training along the USA–Mexico border have prompted concerns about long-term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from anthropogenic activities, we developed a series of erosion potential models based on factors from the Universal Soil Loss Equation (USLE). To better express the vulnerability of soils to human disturbances, we refined two factors whose categorical and spatial representations limit the application of the USLE for non-agricultural landscapes: the C -factor (vegetation cover) and the P -factor (support practice/management). A soil compaction index ( P -factor) was calculated as the difference in saturated hydrologic conductivity ( K s ) between disturbed and undisturbed soils, which was then scaled up to maps of vehicle disturbances digitized from aerial photography. The C -factor was improved using a satellite-based vegetation index, which was better correlated with estimated ground cover ( r 2  = 0·77) than data derived from land cover ( r 2  = 0·06). We identified 9,780 km of unauthorized off-road tracks in the 2,800-km 2 study area. Maps of these disturbances, when integrated with soil compaction data using the USLE, provided landscape-scale information on areas vulnerable to erosion from both natural processes and human activities and are detailed enough for adaptive management and restoration planning. The models revealed erosion potential hotspots adjacent to the border and within areas managed as critical habitat for the threatened flat-tailed horned lizard and endangered Sonoran pronghorn.

Land Degradation and Development↗

USGS1997

Disturbance of biological soil crusts: Impacts on potential wind erodibility of sandy desert soils in southeastern Utah

Friction threshold velocities (FTVs) were determined for biological soil crusts in different stages of recovery. Particles on the surface of crusts that had been relatively undisturbed for at least 20 years were found to have significantly higher FTVs than those that had been disturbed 5, 10 or 1 years previously (376, 87, and 46 cm sec -1 , respectively). FTV's for crust breakage was also much higher for undisturbed crusts when compared to the previously disturbed crusts (573, 148, and 88 cm sec -1 , respectively). All crusted surfaces were more stable than bare sand, which had an FTV of 16 cm sec -1 . Disturbance treatments were then applied to the three crustal classes. Disturbance significantly reduced the FTVs of all classes by 73±92 per cent. Comparing crustal FTVs with mean and high monthly wind speeds found in this region, it was observed that only crusts that had been undisturbed for approximately 20 years or more were able to protect soil surfaces from wind gusts expected on the average of once a month. Other crustal classes, as well as all disturbance treatments, had FTVs lower or equal to that of commonly occurring winds in this region. Because most of the crustal biomass occurs in the top 0-3 mm of soils, even slight soil loss can negatively influence stability and nutrient inputs to this ecosystem.

Utah↗

USGS2007

Soil properties and perceived disturbance of grasslands subjected to mechanized military training: Evaluation of an index

Mechanized maneuver training impacts the landscape by creating depressions, compacting soils, producing bare ground areas, transporting seeds of invasive plants, and crushing vegetation. We measured 3 physical, 13 chemical, and 2 biological soil properties and used a disturbance index (DI) based on perceptions of soil conditions on a military installation to assess the condition of 100 ?? 100 m plots (1 ha): 10 in 2002 and 10 in 2004. Potential DI scores range from 0 (no appreciable evidence of disturbance) to 1 (>95 per cent of the plot disturbed). Bulk density, porosity (%), and water content (%) - all at 5-1-10-0cm depth, and nematode family richness (NFR) were significantly, negatively correlated (Spearman coefficients, rs) with the DI of both years. The strong negative correlation (rs., = -0.69 in 2002, -0.79 in 2004) of NFR with the DI appears to reflect the status of nematode diversity and, therefore, may serve as a useful, inexpensive approach to rapidly assessing grasslands subjected to mechanized military training. Copyright ?? 2007 John Wiley & Sons, Ltd.

Land Degradation and Development↗

USGS2009

Effects of fire temperature on the physical and chemical characteristics of the ash from two plots of Cork oak (Quercus Suber)

Cork oak, (Quercus suber) is widely distributed in the Mediterranean region, an area subject to frequent fires. The ash produced by burning can have impacts on the soil status and water resources that can differ according to the temperature reached during fire and the characteristics of the litter, defined as the dead organic matter accumulated on the soil surface prior to the fire. The aim of this work is to determine the physical and chemical characteristics of ash produced in laboratory experiments to approximate conditions typical of fires in this region. The litter of Quercus suber collected from two different plots on the Iberian Peninsula, Mas Bassets (Catalonia) and Albufeira (Portugal), was combusted at different temperatures for 2h. We measured Mass Loss (ML per cent), ash colour and CaCO 3 content, pH, Electrical Conductivity (EC) and the major cations (Ca 2+ , Mg 2+ , K + and Na + ) released from ash slurries created by mixing ash with deionized water. The results showed that ML per cent is higher at all temperatures in Albufeira samples compared to Mas Bassets samples, except at 550??C, and the rate of loss increases faster with temperature than the Mas Bassets samples. At 150??C the ash colour is yellowish, becoming reddish at 200- 250??C and black at 300??C. Above 400??C the ash is grey/white. This thermal degradation is mostly observed in Albufeira litter. The formation of CaCO 3 was identified at a lower temperature in Albufeira litter. At temperatures <300??C, pH and EC values are lower, rising at higher temperatures, especially in Albufeira slurries. The concentration of cations at lower temperatures does not differ substantially from the unburned sample except for Mg 2+ . The cation concentration increases at medium temperatures and decrease at higher temperatures, especially the concentration of divalent cations. The monovalent cations showed a larger concentration at moderate temperatures, mainly in Albufeira ash slurries. The analysis of the Ca:Mg ratio also showed that for the same temperature, a higher severity results for Albufeira litter. Potential negative effects on soil properties are observed at medium and higher temperatures. These negative effects include a higher percentage of mass loss, meaning more soil may be exposed to erosion, higher pH values and greater cation release from ash, especially monovalalent cations (K + ,Na + ) in higher proportions than the divalent ions (Ca 2+ , Mg 2+ ), that can lead to impacts on soil physical properties like aggregate stability. Furthermore, the ions in ash may alter soil chemistry which may be detrimental to some plants thus altering the recovery of these ecosystems after fire. Low intensity prescribed fire can be a useful tool to land management in these sites, due to the reduced effects of fire temperatures on the physical and chemical properties of surface litter, and can reduce the risk of high temperature wildland fires by reducing fuel loadings. From the perspective of water resources, lower fire temperatures produce fewer impacts on the chemistry of overland flow and there is less probability that the soil surface will be eroded. Copyright ?? 2009 John Wiley & Sons, Ltd.

Land Degradation and Development↗

USGS2024

Adaptive capacities of inland fisheries facing anthropogenic pressures

Inland fisheries face multiple, intensifying threats (i.e., proximate human pressures causing degraded ecological attributes) from land development, climate change, resource extraction, and competing demands for water resources. Planning for resiliency amidst these pressures requires understanding the factors that influence an inland fishery’s capacity to adapt to system changes under multiple threats. Incorporating expert knowledge can illuminate priority fisheries and provide important insights where data are otherwise limited. Using data from a global survey of 536 fishery professionals, this study examines perceptions of threats and adaptive capacity (i.e., ability to mitigate or respond to change) in major inland fisheries. We assessed associations across 29 different perceived threats and their ranked influence scores, tested agreement among five adaptive capacity domains (i.e., agency, assets, flexibility, learning, organization), and examined relationships between threats and adaptive capacity domains. Results provide quantitative evidence that the greatest threats to inland fisheries come from outside the fishing sector and that most inland fisheries face multiple threats. Results also support the five domains as a collective measure of adaptive capacity and illuminate a negative association between the threats to a fishery and a fishery’s adaptive capacity. These findings highlight the need for fishery managers to engage in decision making with non-fishery sectors (e.g., multi-sectoral management) and the prioritization of habitat and watershed-scale conservation and rehabilitation efforts for improved adaptability amidst ecological transformation.

Global Environmental Change↗

USGS2000

Water quality and macroinvertebrate communities of Emigration and Red Butte Creeks, Salt Lake County, Utah

Residential development in the canyons and foothills surrounding Salt Lake City, Utah, is growing at a rapid pace. Urban development typically degrades the water quality when formerly natural lands are developed. In Emigration Canyon, however, residential development is replacing land formerly used for grazing and recreation. It is not clear how this land use change has affected the water quality and biotic communities in this watershed. The water quality and macroinvertebrate communities of Emigration Creek and neighboring Red Butte Creek were examined by the U.S. Geological Survey (USGS) as part of the National Water-Quality Assessment Program (NAWQA) during summer 1999.

Utah↗

USGS2024

Pesticides in surface water downstream of and near agricultural and developed land in Hawai‘i, 2015–19

Pesticides and pesticide degradates (herein referred to as pesticides) in surface water were assessed at 78 sites on 4 Hawaiian Islands (Kauaʻi, Oʻahu, Maui, and Island of Hawaiʻi) during 2015–19. Each site was downstream of or near agricultural land, developed land, or both. Most (58) sites were streams; the remaining sites were canals, ditches, anchialine pools, coastal ponds, and the nearshore ocean. Pesticides in water at each site were assessed by collection of one to four water samples, by a weeks-long deployment of a passive sampler, or both. Passive-sampler extracts and water samples, which consisted of fair-weather samples and storm samples, were analyzed for as many as 253 pesticides that consisted of 129 herbicides, 101 insecticides, and 23 fungicides. A total of 117 pesticides were detected in water. Of these, 30 pesticides were detected at more than 20 percent of their assessment sites and thus were considered “common” pesticides. The common pesticides included 17 herbicides (ametryn, atrazine, bentazon, bromacil, diuron, hexazinone, metolachlor, propazine, simazine, triclopyr, prometryn, and degradates of atrazine [4], diuron, hexazinone, and prometryn); 8 insecticides (carbaryl, dinotefuran, fipronil, flubendiamide, imidacloprid, methoxyfenozide and 2 degradates of fipronil); and 5 fungicides (azoxystrobin, metalaxyl, propiconazole, a degradate of chlorothalonil, and a degradate of thiophanate-methyl and benomyl). Common pesticides typically were present more frequently in storm samples than in fair-weather samples. A mixture of two or more pesticides was detected in 86 percent of the water samples and in water during every passive-sampler deployment. About 92 percent of all pesticide detections had concentrations less than 100 nanograms per liter. Pesticide concentrations were less than Federal aquatic-life benchmarks (ALBs) for vertebrates and typically were less than ALBs for invertebrates, nonvascular plants, and vascular plants. Acute ALBs were exceeded by acetochlor, atrazine, carbaryl, chlorpyrifos, cis-permethrin, diazinon, diuron, halosulfuron methyl, and imidacloprid in storm samples at one to four sites. ALBs for invertebrates were exceeded by clothianidin, diazinon, fipronil, and imidacloprid in fair-weather samples, during passive-sampler deployments, or both at 1 to 17 sites. Federal drinking water standards were available for only five pesticides detected in water, and the standard for atrazine was exceeded in one storm sample. Pesticide concentrations did not exceed any Federal human-health benchmarks, but many of the detected pesticides did not have a benchmark.

Hawaii↗

USGS2019

A comparison of hydrocarbon-related landscape disturbance patterns along the New York-Pennsylvania border, 2004–2013

Executive Summary The New York-Pennsylvania area has a long history of hydrocarbon extraction, and the addition of shale gas extraction methods contributes to landscape disturbance borne by previously developed oil and non-shale gas resources. The main unconventional extraction method used to extract shale gas from the Marcellus Shale located in New York and Pennsylvania is hydraulic fracturing, or “fracking,” although other conventional methods are used extensively. All forms of hydrocarbon extraction disturb the surrounding landscape to some extent, primarily in the form of land clearance and degradation, road construction, and pipeline development, although the effects of these disturbances are not fully understood. In this study, landscape-change metrics and indicators are used to analyze change in a 10-county region along the New York-Pennsylvania border—the New York counties of Allegany, Steuben, Chemung, Tioga, and Broome, and the Pennsylvania counties of McKean, Potter, Tioga, Bradford, and Susquehanna. This 10-county region was selected due to the differences in policies between the States of New York and Pennsylvania. While fracking occurred extensively in Pennsylvania over the past 10 years or more, the State of New York issued a temporary moratorium against hydraulic fracturing in 2010—citing repercussions that might affect air quality, water quality, and public health—and officially banned hydraulic fracturing in June 2015. The quantification of landscape disturbance due to hydrocarbon extraction activities is presented in this report as land-use and land-cover (LULC) change between 2004 and 2013 and defined using specific disturbance categories (including well sites, roads, and pipelines) to compare the disturbances and changes, by county, on both sides of the New York-Pennsylvania border. The quantification was accomplished by gathering the signatures of disturbance from high-resolution aerial images, comparing the derived totals of disturbance, and then computing landscape metrics in a geographic information system (GIS) environment. The collected data represent a summation of landscape disturbance from oil and gas development, as some of the data represented were established decades earlier. The Analytical Tools Interface for Landscape Assessments (ATtILA) software was used to calculate land-cover area and landscape metrics for each shale gas, non-shale gas, oil, and other infrastructure types associated with hydrocarbons across each county and both five-county regions in the study area. The three primary metrics used to describe changes in forest structure were (1)forest area, (2) interior forest area, and (3) forest edge area. The changes in metrics were subsequently evaluated using the Pearson correlation coefficient. Overall, the disturbed-area footprint in the Pennsylvania region is considerably larger than the disturbed-area footprint in the New York region (13,687.9 hectares [ha] in Pennsylvania; 3,840.5 ha in New York). Disturbance per site is similar, with 1.2 disturbed ha per site in New York and 1.6 disturbed ha per site in Pennsylvania. In the New York-Pennsylvania 10-county region, hydrocarbon-development and extraction disturbance strongly correlate with a reduction in the percentage of forest for the entire region. This observation also appears to be true in the New York five-county region for forest area. This form of disturbance in the New York five-county region shows significantly correlated changes in forest metrics (–0.4 percent total forest area), particularly in the percentage of interior forest (–1.2 percent total area) and forest edge (+0.7 percent total area). On the other hand, gas and hydrocarbon-development and extraction disturbance (1.0 percent total area) in the Pennsylvania five-county region strongly correlates with a total decline in forest area and agricultural land area (–0.8 percent combined total area) but not with either land-cover class separately.

New York, Pennsylvania↗

USGS2011

Application of a watershed model (HSPF) for evaluating sources and transport of pathogen indicators in the Chino Basin drainage area, San Bernardino County, California

A watershed model using Hydrologic Simulation Program-FORTRAN (HSPF) was developed for the urbanized Chino Basin in southern California to simulate the transport of pathogen indicator bacteria, evaluate the flow-component and land-use contributions to bacteria contamination and water-quality degradation throughout the basin, and develop a better understanding of the potential effects of climate and land-use change on water quality. The calibration of the model for indicator bacteria was supported by historical data collected before this study and by samples collected by the U.S. Geological Survey from targeted land-use areas during storms in water-year 2004. The model was successfully calibrated for streamflow at 5 gage locations representing the Chino Creek and Mill Creek drainages. Although representing pathogens as dissolved constituents limits the model's ability to simulate the transport of pathogen indicator bacteria, the bacteria concentrations measured over the period 1998-2004 were well represented by the simulated concentrations for most locations. Hourly concentrations were more difficult to predict because of high variability in measured bacteria concentrations. In general, model simulations indicated that the residential and commercial land uses were the dominant sources for most of the pathogen indicator bacteria during low streamflows. However, simulations indicated that land used for intensive livestock (dairies and feedlots) and mixed agriculture contributed the most bacteria during storms. The calibrated model was used to evaluate how various land use, air temperature, and precipitation scenarios would affect flow and transport of bacteria. Results indicated that snow pack formation and melt were sensitive to changes in air temperature in the northern, mountainous part of the Chino Basin, causing the timing and magnitude of streamflow to shift in the natural drainages and impact the urbanized areas of the central Chino Basin. The relation between bacteria concentrations and air temperature was more complicated, and did not substantially affect the quality of water discharging from the Chino Basin into the Santa Ana River. Changes in precipitation had a greater basin-wide affect on bacteria concentrations than changes in air temperature, and varied according to location. Drainages representing natural conditions had a decrease in bacteria concentrations in correlation with an increase in precipitation, whereas drainages in the central and southern part of the Chino Basin had an increase in bacteria concentrations. Drier climate conditions tended to result in higher sensitivity of simulated bacteria concentrations to changes in precipitation. Simulated bacteria concentrations in wetter climates were usually less sensitive to changes in precipitation because bacteria transport becomes more dependent on the land-use specified bacteria loading rates and the storage limits. Bacteria contamination from impervious-area runoff is affected to a greater degree by drier climates, whereas contamination from pervious-area runoff is affected to a greater degree by wetter climates. Model results indicated that the relation between precipitation, runoff, and bacteria contamination is complicated because after the initial bacteria washoff and transport from the land surfaces during the beginning of a storm period, subsequent runoff has fewer bacteria available for washoff, which then dilutes the concentrations of bacteria in the downstream reach. It was illustrated that pathogen indicator bacteria transport depends most significantly on the relation of imperviousness to runoff, which controls the frequency, and often the magnitude, of transport, and on the contribution of higher bacteria loading rates used for pervious land areas, especially intensive feedlots, to the infrequent, but very high, peaks of bacteria contamination. The indicator bacteria transport model for the Chino Basin was based on the assumption that no

California↗

USGS2010

Land Disturbance Associated with Oil and Gas Development and Effects of Development-Related Land Disturbance on Dissolved-Solids Loads in Streams in the Upper Colorado River Basin, 1991, 2007, and 2025

Oil and gas resource development in the Upper Colorado River Basin (UCRB) has increased substantially since the year 2000. The UCRB encompasses several significant oil and gas producing areas that have the potential for continued oil and gas resource development. Land disturbance associated with oil and gas resource development is caused by activities related to constructing drill pads to contain drilling and well maintenance equipment and roads to access the drill pad. Land disturbed by oil and gas development has the potential to cause increased erosion, stream degradation, habitat fragmentation and alteration, and increase public use of areas that may be environmentally sensitive. Land disturbance resulting from oil and gas resource development has not been monitored and mapped on a regional scale in the UCRB. However, information on the location and age of oil and gas wells in the UCRB is available. These data combined with geographic data analysis and modeling techniques were used to estimate the total area of disturbed land associated with oil and gas resource development in 1991 and in 2007 in the UCRB. Additional information about anticipated oil and gas development in the UCRB was used to project land disturbance to the year 2025. Results of the analysis indicate that approximately 117,500 acres (183 mi2) of total land disturbance was associated with drill pads and related roads in the UCRB in 1991. The estimated area of disturbed land associated with oil and gas development increased 53 percent to 179,400 acres (280 mi2) in 2007. Projecting oil and gas development through 2025 results in a potential near doubling of the land surface disturbance to approximately 319,300 acres (500 mi2). Estimated land disturbance for 1991 and 2007 were input to a contaminant transport model developed for the UCRB to assess the statistical significance of energy-related land disturbance to contributing dissolved solids to basin streams. The statistical assessment was an observational study based on an existing model and available water-quality monitoring data for the basin. No new data were collected for the analysis. The source coefficient calibrated for the disturbed lands associated with oil and gas development in 2007 was zero, which indicated that estimated land disturbance from oil and gas development is not statistically significant in explaining dissolved solids in UCRB streams. The lack of significance in the contaminant transport modeling framework may be due to the amount of available monitoring data, the spatial distribution of monitoring sites with respect to land disturbance, or the overall quantity of land disturbance associated with oil and gas development basin wide. Finally, dissolved-solids loads derived from natural landscapes may be similar to loads derived from lands disturbed by oil and gas resource development. The model recalibration done for this study confirms calibration results from Kenney and others (2009): the most significant contributor to dissolved solids in the UCRB is irrigated agricultural land, which covers an area substantially larger than the estimated area disturbed by oil and gas development and is subjected to artificially applied water.

Scientific Investigations Report↗

USGS2001

Environmental geochemistry at the global scale

Land degradation and pollution caused by population pressure and economic development pose a threat to the sustainability of the earth's surface, especially in tropical regions where a long history of chemical weathering has made the surface environment particularly fragile. Systematic baseline geochemical data provide a means of monitoring the state of the environment and identifying problem areas. Regional surveys have already been carried out in some countries, and with increased national and international funding they can be extended to cover the rest of the land surface of the globe. Preparations have been made, under the auspices of the International Union of Geological Surveys (IUGS) and the International Association of Geochemistry and Cosmochemistry (IAGC) for the establishment of just such an integrated global database. ?? 2001 NERC. Published by Elsevier Science Ltd.

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