SEARCH · Geology Reports

Results for “Four Seasons”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources

USGS2022

A novel regression method for harmonic analysis of time series

Harmonic analysis of time series is an important technique in remote sensing to reveal seasonal land surface dynamics. However, frequency selection in the harmonic analysis is often difficult because high-frequency components are useful for delineating seasonal dynamics but sensitive to noise and gaps in time series. On the other hand, it is challenging to obtain temporally continuous satellite data with high quality because of atmospheric contamination. We developed a novel regression method named Harmonic Adaptive Penalty Operator (HAPO) for harmonic analysis of unevenly distributed time series. We introduced a new penalty function to minimize unexpected fluctuations in the model, which can substantially reduce the overfitting issue of regression in time series with temporal gaps. Specifically, the new penalty function minimizes the length of the model curve and the value range difference between the model and the time series observations. We compared HAPO with three widely used regression methods (OLS: Ordinary Least Squares; LASSO: Least Absolute Shrinkage and Selection Operator; and Ridge) in different scenarios using Landsat time series data across the United States. First, we evaluated methods using the Landsat surface reflectance time series within a single year. HAPO showed low and consistent monthly Root Mean Square Deviation (RMSD) values, in which most of the time RMSD of predicted reflectance were less than 0.04. More importantly, HAPO showed consistent and less bias given varying density and irregularity of time series. Second, we evaluated methods using multi-year time series. HAPO was a better predictor of relatively short time series (< 4 years) with steady low RMSD values. When a longer time series ( 4 years) was used, all four methods showed similar RMSD values, but HAPO outperformed the other methods if there were temporal gaps. Therefore, for places with large seasonal observation gaps or for time series that are relatively short (less than 4 years), HAPO can provide more consistent and accurate results in harmonic analysis of time series.

ISPRS Journal of Photogrammetry and Remote Sensing↗

USGS2014

Hawaiian hoary bat occupancy at Kaloko-Honokōhau National Historical Park

Hawaiian hoary bat ( Lasiurus cinereus semotus ) vocalizations were recorded using Anabat SD1 and Song Meter SM2Bat ultrasonic recorders at four monitoring stations in Kaloko-Honokōhau National Historical Park on the island of Hawai‘i. We hypothesize that echolocation call events are more numerous during the reproductive season of this bat. Bat detectors recorded from 1700 to 0730 hrs on a total of 42 nights between October 2011 and September 2012. Peak activity occurred between 1800 and 2000 hrs, although in May a secondary peak occurred between 0100 and 0300 hrs. Detectability proportions (0 to 1.0) were calculated using the software program PRESENCE (v4.2) and reported for each seven day recording session which was repeated on a bimonthly schedule. Hawaiian hoary bats were present in four of the six bimonthly surveys: January, May, September, and October; however, no bat calls were detected in March or July. Detectability of bat calls was above 0.50 in January, May, and September. Foraging buzzes, indicating feeding activity, were recorded in all months that bats were present.

Hawai'i↗

USGS2002

Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA

We evaluated long-term trends in average maximum and minimum temperatures, threshold temperatures, and growing season in eastern Colorado, USA, to explore the potential shortcomings of many climate-change studies that either: (1) generalize regional patterns from single stations, single seasons, or a few parameters over short duration from averaging dissimilar stations: or (2) generalize an average regional pattern from coarse-scale general circulation models. Based on 11 weather stations, some trends were weakly regionally consistent with previous studies of night-time temperature warming. Long-term (80 + years) mean minimum temperatures increased significantly (P < 0.2) in about half the stations in winter, spring, and autumn and six stations had significant decreases in the number of days per year with temperatures ??? - 17.8 ??C (???0??F). However, spatial and temporal variation in the direction of change was enormous for all the other weather parameters tested, and, in the majority of tests, few stations showed significant trends (even at P < 0.2). In summer, four stations had significant increases and three stations had significant decreases in minimum temperatures, producing a strongly mixed regional signal. Trends in maximum temperature varied seasonally and geographically, as did trends in threshold temperature days ???32.2??C (???90??F) or days ???37.8??C (???100??F). There was evidence of a subregional cooling in autumn's maximum temperatures, with five stations showing significant decreasing trends. There were many geographic anomalies where neighbouring weather stations differed greatly in the magnitude of change or where they had significant and opposite trends. We conclude that sub-regional spatial and seasonal variation cannot be ignored when evaluating the direction and magnitude of climate change. It is unlikely that one or a few weather stations are representative of regional climate trends, and equally unlikely that regionally projected climate change from coarse-scale general circulation models will accurately portray trends at sub-regional scales. However, the assessment of a group of stations for consistent more qualitative trends (such as the number of days less than - 17.8??C, such as we found) provides a reasonably robust procedure to evaluate climate trends and variability. Copyright ?? 2002 Royal Meteorological Society.

International Journal of Climatology↗

USGS2017

Projected warming portends seasonal shifts of stream temperatures in the Crown of the Continent Ecosystem, USA and Canada

Climate warming is expected to increase stream temperatures in mountainous regions of western North America, yet the degree to which future climate change may influence seasonal patterns of stream temperature is uncertain. In this study, a spatially explicit statistical model framework was integrated with empirical stream temperature data (approximately four million bi-hourly recordings) and high-resolution climate and land surface data to estimate monthly stream temperatures and potential change under future climate scenarios in the Crown of the Continent Ecosystem, USA and Canada (72,000 km2). Moderate and extreme warming scenarios forecast increasing stream temperatures during spring, summer, and fall, with the largest increases predicted during summer (July, August, and September). Additionally, thermal regimes characteristic of current August temperatures, the warmest month of the year, may be exceeded during July and September, suggesting an earlier and extended duration of warm summer stream temperatures. Models estimate that the largest magnitude of temperature warming relative to current conditions may be observed during the shoulder months of winter (April and November). Summer stream temperature warming is likely to be most pronounced in glacial-fed streams where models predict the largest magnitude (> 50%) of change due to the loss of alpine glaciers. We provide the first broad-scale analysis of seasonal climate effects on spatiotemporal patterns of stream temperature in the Crown of the Continent Ecosystem for better understanding climate change impacts on freshwater habitats and guiding conservation and climate adaptation strategies.

Climatic Change↗

USGS2002

Fecal-indicator bacteria in the Yakima River Basin, Washington: An examination of 1999 and 2000 synoptic-sampling data and their relation to historical data

The Yakima Basin National Water-Quality Assessment Program collected fecal-coliform bacteria samples during three synoptic samplings to identify and quantify the cause, source, transport, and effects of fecal-indicator bacteria in Yakima River Basin streams. The August 1999 synoptic sampling targeted the Yakima River main-stem and tributary sites, while the July and October-November 2000 synoptic samplings targeted small- and intermediate-sized agricultural watersheds during irrigation and nonirrigation season, respectively. Quality-assurance results indicated that variability in fecal-coliform concentrations is large and, therefore, a difference of an order of magnitude or more between sites or between times is required for the values to be significantly different 90 percent of the time. The August 1999 synoptic sampling results indicated that (1) 44 percent of the sites visited, including all the main-stem Yakima River sites, met the Class A fecal-coliform 90th percentile standard of 200 colonies per deciliter, (2) tributaries were the likely source of fecal contamination to the main stem, and (3) tributaries with high fecal-coliform concentrations typically also had high suspended-sediment concentrations. Results of the July and October-November 2000 synoptic samplings indicated that (1) 36 and 81 percent of the sites sampled, respectively, met the standard, (2) during the nonirrigation synoptic sampling, four of the six sites not meeting the standard were from the Granger and Sulphur subbasins, and (3) fecal-coliform concentrations during the irrigation season were generally higher than during the nonirrigation season. Several levels of temporal variability were examined. The short-term variability observed during a synoptic sampling was found to be site specific, with some sites fairly consistent, while others were rather variable. Seasonally, most sites from the 2000 synoptic samplings showed higher concentrations during irrigation than during nonirrigation. Historically, 13 of the 22 sites sampled during both the July 1988 and August 1999 synoptic samplings had higher concentrations in 1999. The three sites with the highest concentrations in July 1988, however, all had decreases in August 1999. When compared against historical (1972-85) minimum and maximum summer-month medians, the August 1999 synoptic-sampling concentrations generally were between these values. Instantaneous fecal-coliform bacteria loads were calculated for the August 1999 synoptic sampling in an effort to study the dynamics of bacterial transport. Tributaries affected by agricultural, urban, and hobby farm activities were generally the major sources of bacteria to the main-stem Yakima River during this time. When these August 1999 synoptic-sampling loads in the lower basin reach from the Yakima River at river mile 72 to Kiona (river mile 29.9) were compared to those from the July 1988 synoptic sampling, most sites had higher loads in 1999. A nonparametric Spearman test was used to detect correlations between fecal-coliform concentrations and physical and chemical data collected during the synoptic samplings. Results for the August 1999 synoptic sampling, which included many mouths of tributaries, showed strong significant correlations with almost every variable. In contrast, only some of the nutrient concentrations showed strong significant correlations during the July and October-November 2000 synoptic samplings, which included small and intermediate- sized agricultural streams. Looking forward relative to future monitoring goals, research needs, and best management practice development, four hypotheses that deal with processes and sources of bacteria were identified: (1) overland runoff transports bacteria from land surfaces to streams, (2) bacteria in the water column tend to associate with suspended matter, (3) with increasing densities of warm-blooded animals, the likelihood of fecal-coliform contamination in streams also increases, and (4) identifi- cation of bacterial sources is difficult, but must be attempted for remediation to be possible.

Washington↗

USGS2016

Organic contaminants in Great Lakes tributaries: Prevalence and potential aquatic toxicity

Organic compounds used in agriculture, industry, and households make their way into surface waters through runoff, leaking septic-conveyance systems, regulated and unregulated discharges, and combined sewer overflows, among other sources. Concentrations of these organic waste compounds (OWCs) in some Great Lakes tributaries indicate a high potential for adverse impacts on aquatic organisms. During 2010–13, 709 water samples were collected at 57 tributaries, together representing approximately 41% of the total inflow to the lakes. Samples were collected during runoff and low-flow conditions and analyzed for 69 OWCs, including herbicides, insecticides, polycyclic aromatic hydrocarbons, plasticizers, antioxidants, detergent metabolites, fire retardants, non-prescription human drugs, flavors/fragrances, and dyes. Urban-related land cover characteristics were the most important explanatory variables of concentrations of many OWCs. Compared to samples from nonurban watersheds (< 15% urban land cover) samples from urban watersheds (> 15% urban land cover) had nearly four times the number of detected compounds and four times the total sample concentration, on average. Concentration differences between runoff and low-flow conditions were not observed, but seasonal differences were observed in atrazine, metolachlor, DEET, and HHCB concentrations. Water quality benchmarks for individual OWCs were exceeded at 20 sites, and at 7 sites benchmarks were exceeded by a factor of 10 or more. The compounds with the most frequent water quality benchmark exceedances were the PAHs benzo[ a ]pyrene, pyrene, fluoranthene, and anthracene, the detergent metabolite 4-nonylphenol, and the herbicide atrazine. Computed estradiol equivalency quotients (EEQs) using only nonsteroidal endocrine-active compounds indicated medium to high risk of estrogenic effects (intersex or vitellogenin induction) at 10 sites. EEQs at 3 sites were comparable to values reported in effluent. This multifaceted study is the largest, most comprehensive assessment of the occurrence and potential effects of OWCs in the Great Lakes Basin to date.

Great Lakes↗

USGS2017

Intra‐annual variability of Silver Carp populations in the Des Moines River, USA

Since their introduction in the 1970s, Silver Carp Hypophthalmichthys molitrix have spread throughout the Mississippi River basin. Management of any species relies on an accurate understanding of population characteristics and dynamics. However, Silver Carp seasonal sampling variation is unknown. Sampling during periods of peak catch rates would facilitate Silver Carp assessment and management, improving monitoring and removal techniques. The objective of this study was to evaluate adult Silver Carp seasonal sampling variation with boat electroshocking and trammel nets. Silver Carp were collected monthly (April–October) during 2014 and 2015 from four locations in the Des Moines River, Iowa. Trammel nets rarely captured Silver Carp (mean ± SE = 4.9 ± 1.6 fish/net; 60% of fish were captured in 6.3% of net sets) and therefore were not included in analyses. Electroshocking catch rates (CPUEs) exhibited a bimodal distribution, with peak CPUEs generally occurring in May, June, and September and lower catch rates observed during July and August. Catch rates were positively related to river discharge at upstream sites but not at downstream sites. Silver Carp size structure was similar among months and sites except at Cliffland, where fish were smaller during August and October compared to earlier in the year. Finally, Silver Carp condition peaked during April and May and decreased throughout the year except at Keokuk, where peaks were observed during both May and August. Although spatiotemporal variability was substantial, these results suggest that sampling of Silver Carp via electroshocking in May–June and September–October generally produces higher catch rates compared to July–August sampling and generates a more representative size structure. Using site‐specific knowledge, monitoring and surveillance programs could more effectively sample during these periods of high vulnerability and densities in order to manage the spread and impacts of Silver Carp at statewide and regionwide scales.

Iowa↗

USGS1999

Demography of the Yellowstone grizzly bears

We undertook a demographic analysis of the Yellowstone grizzly bears ( Ursus arctos ) to identify critical environmental factors controlling grizzly bear vital rates, and thereby to help evaluate the effectiveness of past management and to identify future conservation issues. We concluded that, within the limits of uncertainty implied by the available data and our methods of data analysis, the size of the Yellowstone grizzly bear population changed little from 1975 to 1995. We found that grizzly bear mortality rates are about double in years when the whitebark pine crop fails than in mast years, and that the population probably declines when the crop fails and increases in mast years. Our model suggests that natural variation in whitebark pine crop size over the last two decades explains more of the perceived fluctuations in Yellowstone grizzly population size than do other variables. Our analysis used demographic data from 202 radio-telemetered bears followed between 1975 and 1992 and accounted for whitebark pine ( Pinus albicaulis ) crop failures during 1993–1995. We used a maximum likelihood method to estimate demographic parameters and used the Akaike Information Criteria to judge the significance of various independent variables. We identified no independent variables correlated with grizzly bear fecundity. In order of importance, we found that grizzly bear mortality rates are correlated with season, whitebark pine crop size (mast vs. nonmast year), sex, management-trapping status (never management-trapped vs. mangement-trapped once or more), and age. The mortality rate of bears that were management-trapped at least once was almost double that of bears that were never management-trapped, implying a source/sink (i.e., never management-trapped/management-trapped) structure. The rate at which bears move between the source and sink, estimated as the management-trapping rate ( h ), is critical to estimating the finite rate of increase, λ͞ . We quantified h by estimating the rate at which bears that have never been management-trapped are management-trapped for the first time. It differed across seasons, was higher in nonmast than mast years, and varied with age. We calculate that λ͞ = 1.00 from 1975 to 1983 (four mast and five nonmast years) and 1.02 from 1984 to 1995 (seven mast and five nonmast years). Overall, we find that λ͞ = 1.01 ± 0.04 (mean ± 1 se ) from 1975 to 1995. Our models suggest that future management should concentrate on the threats to whitebark pine, such as those posed by white pine blister rust, global warming, and fire suppression. As is currently widely recognized by Yellowstone land managers, our model also suggests that future management must compensate for the increased grizzly bear mortality that is likely to be caused by an increasing number of humans in Yellowstone.

Idaho, Montana, Wyoming↗

USGS1986

Effect of discharge on the chlorophyll a distribution in the tidally-influenced Potomac River

In the tidal Potomac River, high river discharges during the spring are associated with high chlorophyll a concentrations in the following in the following summer, assuming that summertime light and temperature conditions are favorable. Spring floods deliver large loads of particulate N and P to the tidal river. This particulate N and P could be mineralized by bacteria to inorganic N and P and released to the water column where it is available for phytoplankton use during summertime. However, during the study period relatively low concentrations of chlorophyll a (less than 50 μg l −1 occurred in the tidal river if average monthly discharge during July or August exceeded 200 m 3 s −1 . Discharge and other conditions combined to produce conditions favorable for nuisance levels of chlorophyll a (greater than 100 μg l −1 approximately one year out of four. Chlorophyll a maxima occurred in the Potomac River transition zone and estuary during late winter (dinoflagellates) and spring (diatoms). Typical seasonal peak concentrations were achieved at discharges as high as 970 m 3 s −1 , but sustained discharges greater than 1,100 m 3 s −1 retarded development. Optimum growth conditions occurred following runoff events of 10 to 15 d duration which produced transit times to the transition zone of 7 to 10 d. Wet years with numerous moderate-sized runoff events, such as 1980, tend to produce greater biomass in the transition zone and estuary than do dry years such as 1981.

Potomac River↗

USGS2012

Dissolved oxygen analysis, TMDL model comparison, and particulate matter shunting—Preliminary results from three model scenarios for the Klamath River upstream of Keno Dam, Oregon

Efforts are underway to identify actions that would improve water quality in the Link River to Keno Dam reach of the Upper Klamath River in south-central Oregon. To provide further insight into water-quality improvement options, three scenarios were developed, run, and analyzed using previously calibrated CE-QUAL-W2 hydrodynamic and water-quality models. Additional scenarios are under development as part of this ongoing study. Most of these scenarios evaluate changes relative to a "current conditions" model, but in some cases a "natural conditions" model was used that simulated the reach without the effect of point and nonpoint sources and set Upper Klamath Lake at its Total Maximum Daily Load (TMDL) targets. These scenarios were simulated using a model developed by the U.S. Geological Survey (USGS) and Watercourse Engineering, Inc. for the years 2006–09, referred to here as the "USGS model." Another model of the reach was developed by Tetra Tech, Inc. for years 2000 and 2002 to support the Klamath River TMDL process; that model is referred to here as the "TMDL model." The three scenarios described in this report included (1) an analysis of whether this reach of the Upper Klamath River would be in compliance with dissolved oxygen standards if sources met TMDL allocations, (2) an application of more recent datasets to the TMDL model with comparison to results from the USGS model, and (3) an examination of the effect on dissolved oxygen in the Klamath River if particulate material were stopped from entering Klamath Project diversion canals. Updates and modifications to the USGS model are in progress, so in the future these scenarios will be reanalyzed with the updated model and the interim results presented here will be superseded. Significant findings from this phase of the investigation include: * The TMDL analysis used depth-averaged dissolved oxygen concentrations from model output for comparison with dissolved oxygen standards. The Oregon dissolved oxygen standards do not specify whether the numeric criteria are based on depth-averaged dissolved oxygen concentration; this was an interpretation of the standards rule by the Oregon Department of Environmental Quality (ODEQ). In this study, both depth-averaged and volume-averaged dissolved oxygen concentrations were calculated from model output. Results showed that modeled depth-averaged concentrations typically were lower than volume-averaged dissolved oxygen concentrations because depth-averaging gives a higher weight to small volume areas near the channel bottom that often have lower dissolved oxygen concentrations. Results from model scenarios in this study are reported using volume-averaged dissolved oxygen concentrations. * Under all scenarios analyzed, violations of the dissolved oxygen standard occurred most often in summer. Of the three dissolved oxygen criteria that must be met, the 30-day standard was violated most frequently. Under the base case (current conditions), fewer violations occurred in the upstream part of the reach. More violations occurred in the down-stream direction, due in part to oxygen demand from the decay of algae and organic matter from Link River and other inflows. * A condition in which Upper Klamath Lake and its Link River outflow achieved Upper Klamath Lake TMDL water-quality targets was most effective in reducing the number of violations of the dissolved oxygen standard in the Link River to Keno Dam reach of the Klamath River. The condition in which point and nonpoint sources within the Link River to Keno Dam reach met Klamath River TMDL allocations had no effect on dissolved oxygen compliance in some locations and a small effect in others under current conditions. On the other hand, meeting TMDL allocations for nonpoint and point sources was predicted to be important in meeting dissolved oxygen criteria when Upper Klamath Lake and Link River also met Upper Klamath TMDL water-quality targets. * The location of greatest dissolved oxygen improvement from nutrient and organic matter reductions was downstream from point and nonpoint source inflows because time and distance are required for decay to occur and for oxygen demand to be exerted. * After assessing compliance with dissolved oxygen standards at all 102 model segments in the Link River to Keno Dam reach, it was determined that the seven locations used by ODEQ appear to be a representative subset of the reach for dissolved oxygen analysis. * The USGS and TMDL models were qualitatively compared by running both models for the 2006–09 period but preserving the essential characteristics of each, such as organic matter partitioning, bathymetric representation, and parameter rates. The analysis revealed that some constituents were not greatly affected by the differing algorithms, rates, and assumptions in the two models. Conversely, other constituents, especially organic matter, were simulated differently by the two models. Organic matter in this river system is best represented by a mixture of relatively labile particulate material and a substantial concentration of refractory dissolved material. In addition, the use of a first-order sediment oxygen demand, as in the USGS model, helps to capture the seasonal and dynamic effect of settled organic and algal material. * Simulation of shunting (diverting) particulate material away from the intake of four Klamath Project diversion canals, so that the material stayed in the river and out of the Project area, caused higher concentrations of particulate material to occur in the river. In all cases modeled, the increase in in-river particulate material also produced decreased dissolved oxygen concentrations and an increase in the number of days when dissolved oxygen standards were violated. * If particulate material were shunted back into the river at the Klamath Project diversion canals, less organic matter and nutrients would be taken into the Klamath Project area and the Lost River basin, resulting in return flows to the Klamath River via Lost River Diversion Channel that may have reduced nutrient concentrations. Model scenarios bracketing potential end-member nutrient concentrations showed that the composition of the return flows had little to no effect on dissolved oxygen compliance under simulated conditions.

Oregon↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1992 through September 1994

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data are presented from January 1992 through September 1994. This report concentrates on data from July through September 1994, and references historic data from 1992 through June 1994. Total rainfall for the first nine months of 1994 was about 77 inches which is 72 percent of the mean annual rainfall of 106 inches. In comparison, total rainfall for the first nine months of 1992 and 1993 was 67 inches and 69 inches, respectively. Annual rainfall totals in 1992 and 1993 were 93 inches and 95 inches, respectively. Ground-water withdrawal during July through September 1994 has averaged 919,400 gallons per day, while annual withdrawals in 1992 and 1993 averaged 935,900 gallons per day and 953,800 gallons per day, respectively. At the end of September 1994, the chloride concentration of the composite water supply was 56 milligrams per liter, well below the 250 milligrams per liter secondary drinking-water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply from July through September 1994 ranged between 51 and 78 milligrams per liter. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations increased in July and August, but have leveled off or decreased in September. There has been a general trend of increasing chloride concentrations in the deeper monitoring wells since the 1992 dry season, which began in March 1992. A fuel leak at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water-supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration by recirculating 150,000 gallons of water each day.

Open-File Report↗

USGS1995

Status of ground-water resources at U.S. Navy Support Facility, Diego Garcia; summary of hydrologic and climatic data, January 1992 through December 1994

This report contains hydrologic and climatic data that describe the status of ground-water resources at U.S. Navy Support Facility, Diego Garcia. Data presented are from January 1992 through December 1994. This report concentrates on data from October through December 1994, and references previous data from 1992 through 1994. Cumulative rainfall for October through December 1994 was 55 inches which is higher than the mean cumulative rainfall of about 31 inches for the same 3 months. Total rainfall for 1994 was 131 inches which is 24 percent higher than the mean annual rainfall of 106 inches. In com- parison, total rainfall in 1992 and 1993 were 93 inches and 95 inches, respectively. Ground-water withdrawal during October through December 1994 averaged 903,000 gallons per day, while the annual withdrawal in 1994 was 942,700 gallons per day. Annual withdrawals in 1992 and 1993 averaged 935,900 gallons per day and 953,800 gallons per day, respectively. At the end of December 1994, the chloride concentration of the composite water supply was 28 milligrams per liter, well below the 250 milligrams per liter secondary drinking-water standard established by the U.S. Environmental Protection Agency. Chloride concentrations of the composite water supply from October through December 1994 ranged between 28 and 86 milligrams per liter. Chloride concentration of ground water in monitoring wells at Cantonment and Air Operations decreased in November and December, and seems to have leveled off by the end of the year. Although chloride concen- trations have decreased during the fourth quarter of 1994, there has been a general trend of increasing chloride concentrations in the deeper monitoring wells since the 1992 dry season, which began in March 1992. A fuel leak at Air Operations caused the shutdown of ten wells in May 1991. Four of the wells resumed pumping for water-supply purposes in April 1992. The remaining six wells are being used to hydraulically contain and divert fuel migration by recirculating 150,000 gallons of water each day.

Open-File Report↗

USGS1994

A technique for estimating ground-water levels at sites in Rhode Island from observation-well data

Estimates of future high, median, and low ground-water levels in Rhode Island are needed for engineering and architectural design decisions and for appropriate selection of land uses. For example, the failure of individual underground sewage-disposal systems due to high ground-water levels can be avoided if accurate water-level estimates are available. Estimates of extreme or average conditions are needed because short-duration re-construction observations are unlikely to be representative. The technique described in this report utilizes a single water-level measurement at a site of interest, in combination with a long-term water-level record at an observation well, to estimate the long-term high, median, and low water levels at the site of interest. The transfer of information to the site of interest depends on four fundamental assumptions: (1) Water levels will fluctuate in the future as they have in the past, (2) Water levels fluctuate seasonally, (3) Ground-water fluctuations depend on site geology, and (4) Water levels throughout Rhode Island are affected by similar precipitation and climate. The technique is based on the equivalent relation between the ratio of potential water-level change to maximum annual water-level range at the site and the ratio of potential water-level change to annual water-level range at the observation well. Equations for estimating high, median, and low water levels, and graphs of probable annual water-level range are given for selecting representative ranges of water levels for sand and gravel and till in Rhode Island. The accuracy of the technique is evaluated by use of the equations to estimate water levels at long-term observation wells where high, median, and low water levels are known from monthly measurements over many years. As a test of the estimating procedure, 6,697 estimates each of high, median, and low water levels (depth to water level exceeded 95, 50, and 5 percent of the time, respectively) were compared with measured water levels exceeded 95, 50, and 5 percent of the time at 14 sites unaffected by pumping or other known factors. Mean squared errors (average differences squared, between estimated and measured water levels) for the estimates ranged from 0.34 to 1.53 ft 2 for high water levels, 0.30 to 1.22 ft 2 for median water levels, and 0.32 to 2.55 ft 2 for low water levels. All mean squared errors are less than the State required 3-foot separation between the bottom of the stone underlying the seepage system and the maximum altitude of the water table. This degree of accuracy is acceptable for many design purposes.

Rhode Island↗

USGS2021

Exploring biophysical linkages between coastal forestry management practices and aquatic bivalve contaminant exposure

Terrestrial land use activities present cross-ecosystem threats to riverine and marine species and processes. Specifically, pesticide runoff can disrupt hormonal, reproductive, and developmental processes in aquatic organisms, yet non-point source pollution is difficult to trace and quantify. In Oregon, U.S.A., state and federal forestry pesticide regulations, designed to meet regulatory water quality requirements, differ in buffer size and pesticide applications. We deployed passive water samplers and collected riverine and estuarine bivalves Margaritifera falcata , Mya arenaria , and Crassostrea gigas from Oregon Coast watersheds to examine forestry-specific pesticide contamination. We used non-metric multidimensional scaling and regression to relate concentrations and types of pesticide contamination across watersheds to ownership and management metrics. In bivalve samples collected from eight coastal watersheds, we measured twelve unique pesticides (two herbicides; three fungicides; and seven insecticides). Pesticides were detected in 38% of bivalve samples; and frequency and maximum concentrations varied by season, species, and watershed with indaziflam (herbicide) the only current-use forestry pesticide detected. Using passive water samplers, we measured four current-use herbicides corresponding with planned herbicide applications; hexazinone and atrazine were most frequently detected. Details about types and levels of exposure provide insight into effectiveness of current forest management practices in controlling transport of forest-use pesticides. View Full-Text

Oregon↗

USGS2006

Direct seeding woody species for restoration of bottomlands

I direct seeded (broadcast) seeds of 39 species of trees and shrubs using an ATV-mounted rotary spreader to initiate restoration of bottomland forest on retired agricultural sites. Four sites were planted during February, 2000, and 13 additional sites were planted during April and May, 2001. After two growing seasons, stem density of direct-seeded species varied greatly among study plots (range = 0 to 888 stems/ha) but averaged only 110 stems/ha. I recommend that future efforts at direct seeding focus on seven shrub species (Amorpha fruticosa L., Cephalanthus occidentalis L., Cornus spp., Crataegus spp., Ilex decidua Walt., Morus rubra L., and Prunus spp.) and seven tree species (Celtis laevigata Willd., Diospyros virginiana L., Fraxinus spp., Gleditsia triacanthos L., Robinia pseudoacacia L., Taxodium distichum (L.) Rich, and Ulmus spp.) that successfully established in these trials.

Book chapter↗

USGS2009

Projected changes in atmospheric heating due to changes in fire disturbance and the snow season in the western Arctic, 2003–2100

In high latitudes, changes in climate impact fire regimes and snow cover duration, altering the surface albedo and the heating of the regional atmosphere. In the western Arctic, under four scenarios of future climate change and future fire regimes (2003–2100), we examined changes in surface albedo and the related changes in regional atmospheric heating due to: (1) vegetation changes following a changing fire regime, and (2) changes in snow cover duration. We used a spatially explicit dynamic vegetation model (Alaskan Frame-based Ecosystem Code) to simulate changes in successional dynamics associated with fire under the future climate scenarios, and the Terrestrial Ecosystem Model to simulate changes in snow cover. Changes in summer heating due to the changes in the forest stand age distributions under future fire regimes showed a slight cooling effect due to increases in summer albedo (mean across climates of −0.9 W m −2 decade −1 ). Over this same time period, decreases in snow cover (mean reduction in the snow season of 4.5 d decade −1 ) caused a reduction in albedo, and a heating effect (mean across climates of 4.3 W m −2 decade −1 ). Adding both the summer negative change in atmospheric heating due to changes in fire regimes to the positive changes in atmospheric heating due to changes in the length of the snow season resulted in a 3.4 W m −2 decade −1 increase in atmospheric heating. These findings highlight the importance of gaining a better understanding of the influences of changes in surface albedo on atmospheric heating due to both changes in the fire regime and changes in snow cover duration.

Journal of Geophysical Research: Biogeosciences↗

USGS2023

Why hibernate? Tests of four hypotheses to explain intraspecific variation in hibernation phenology

Hibernation is a remarkable behaviour deployed by a diverse array of endotherms within many clades that greatly reduces metabolic need, but also has somatic costs. Hibernation in modern endotherms is often assumed to be an adaptation allowing animals to avoid extreme thermal conditions or food shortages in seasonal environments. However, many animals hibernate when foraging conditions are energetically profitable, suggesting other causal factors influence hibernation behaviour. Understanding the selection pressures responsible for intraspecific variation in the timing and duration of hibernation can help elucidate the relative evolutionary influences of the ultimate ecological causes of hibernation. We tested four previously proposed mechanistic hypotheses to explain intraspecific variation in hibernation phenology in the federally threatened northern Idaho ground squirrel ( Urocitellus brunneus ): (1) thermal tolerance, (2) food limitation, (3) predation avoidance and (4) sexual selection. The predation avoidance and sexual selection hypotheses received the most support, although we also found some support for the thermal tolerance and food limitation hypotheses. Heavy squirrels increased hibernation duration regardless of environmental conditions, as predicted solely by the predation avoidance hypothesis. Reproductive males emerged from hibernation earlier in spring than other sex–age classes, a pattern predicted by the sexual selection hypothesis. Temperature and food availability explained a much smaller amount of the variation in hibernation behaviour, only partially supporting predictions of the thermal tolerance and food limitation hypotheses. Our results indicate that animals navigate life-history trade-offs between energetic allocation to survival and reproduction via state-dependent optimization of hibernation phenology. Consequently, any future environmental changes that influence body condition will have implications for population ecology and life-history evolution of hibernating animals due to stark differences in daily survival probability between hibernation and the active season.

Functional Ecology↗

USGS2007

The Quality of Water and Bottom Material in Lunga Reservoir, Virginia, September 2004 through August 2005

Lunga Reservoir is on the U.S. Marine Corps Base in Quantico, which is in the Potomac River basin and the Piedmont Physiographic Province of northern Virginia. Because of the potential use of the reservoir for scuba-diver training and public water supply in addition to current recreational activities, the U.S. Marine Corps wanted to know more about the water quality of Lunga Reservoir and how it compared to Virginia Department of Environmental Quality and Virginia State Water Control Board ambient water-quality standards. Water samples and physical properties were collected by the U.S. Geological Survey at 6 locations throughout Lunga Reservoir, and physical properties were collected at 11 additional locations in the reservoir from September 2004 through August 2005. Water samples for analysis of pesticides and bottom-material trace elements were collected once during the study at four of the sampling locations. Water temperature, dissolved-oxygen concentration, specific conductance, pH, and total chlorophyll concentration in Lunga Reservoir all had similar seasonal and spatial variations as in other lakes and reservoirs in this geographic region - thermal gradient in the summer and fall and isothermal conditions in the winter and early spring. Concentrations of water-quality indicators in Lunga Reservoir were within comparable levels of those in other reservoirs and did not violate the Virginia State Water Control Board standards for public water supplies. Water temperatures throughout Lunga Reservoir during the study period ranged from 4.4 to 30.1 degrees Celsius, well below the State Water Control Board maximum water temperature criteria of 32 degrees Celsius. Dissolved-oxygen concentrations ranged from 0.05 to 14.1 milligrams per liter throughout the reservoir during the study period, but never fell below the State Water Control Board minimum dissolved-oxygen criterion of 4.0 milligrams per liter at the surface of Lunga Reservoir. Specific conductance throughout Lunga Reservoir ranged from 29 to 173 microsiemens per centimeter at 25 degrees Celsius during the study period, with a mean specific conductance of 68 microsiemens per centimeter at 25 degrees Celsius. Measurements of pH throughout the reservoir ranged from 4.8 to 7.6 standard units. Concentrations of chemical constituents analyzed in Lunga Reservoir samples were below any State Water Control Board criteria and generally were similar in concentration to the same chemical constituents in other reservoirs in the State. Four water samples were analyzed for 54 pesticides, and none of these pesticides were above the laboratory minimum reporting level.

Open-File Report↗