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Research about Virginia
Source-linked reports with geographic coverage including Virginia.
Water resources data, Virginia, water year 1994. Volume 1. Surface-water discharge and surface-water quality records
No abstract available.
Water resources data, Virginia, water year 1994. Volume 2: Ground-water level and ground-water quality records
No abstract available.
Methods for estimating the magnitude and frequency of peak discharges of rural, unregulated streams in Virginia
Methods are presented for estimating the peak discharges of rural, unregulated streams in Virginia. A Pearson Type III distribution is fitted to the logarithms of the unregulated annual peak-discharge records from 363 stream-gaging stations in Virginia to estimate the peak discharge at these stations for recurrence intervals of 2 to 500 years. Peak-discharge characteristics for 284 unregulated stations are divided into eight regions based on physiographic province, and regressed on basin characteristics, including drainage area, main channel length, main channel slope, mean basin elevation, percentage of forest cover, mean annual precipitation, and maximum rainfall intensity. Regression equations for each region are computed by use of the generalized least-squares method, which accounts for spatial and temporal correlation between nearby gaging stations. This regression technique weights the significance of each station to the regional equation based on the length of records collected at each cation, the correlation between annual peak discharges among the stations, and the standard deviation of the annual peak discharge for each station. Drainage area proved to be the only significant explanatory variable in four regions, while other regions have as many as three significant variables. Standard errors of the regression equations range from 30 to 80 percent. Alternate equations using drainage area only are provided for the five regions with more than one significant explanatory variable. Methods and sample computations are provided to estimate peak discharges at gaged and engaged sites in Virginia for recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, and to adjust the regression estimates for sites on gaged streams where nearby gaging-station records are available.
Water-quality characteristics of five tributaries to the Chesapeake Bay at the Fall Line, Virginia, July 1988 through June 1993
Development in the Chesapeake Bay region has adversely affected the water quality of the Bay. The general degradation in the Bay has resulted in the decline of commercial fishing industries and has reduced the area of aquatic vegetation that provides food and habitat for fish and shellfish. In order to assess the effectiveness of programs aimed at reducing the effects of excess nutrients and suspended solids on Chesapeake Bay, it is necessary to quantify the loads of these constituents into the Bay, and to evaluate the trends in water quality. This report presents the results of a study funded by the Virginia Department of Environmental Quality Chesapeake Bay and Coastal Programs and the U.S. Geological Survey, to monitor and estimate loads of selected nutrients and suspended solids discharged to Chesapeake Bay from five major tributaries in Virginia. The water-quality data and load estimates provided in this report also will be used to calibrate computer models of Chesapeake Bay. Water-quality constituents were monitored in the James and Rappahannock Rivers over a 5-year period, and in the Pamunkey, Appomattox, and Mattaponi Rivers over a 4-year period. Water-quality samples were collected from July 1, 1988 through June 30, 1993, for the James and Rappahannock Rivers; from July 1, 1989 through June 30, 1993, for the Pamunkey and Appomattox Rivers; and from September 1,1989 through June 30, 1993, for the Mattaponi River. Water-quality samples were collected on a scheduled basis and during stormflow to cover a range in discharge conditions. Monitore water-quality constituents, for which loads were estimated include total suspended solids (residue, total at 105° Celsius), dissolved nitrite-plus-nitrate nitrogen, dissolved ammonia nitrogen, total Kjeldahl nitrogen, total nitrogen, total phosphorus, dissolved orthophosphorus, total organic carbon, and dissolved silica. Organic nitrogen concentrations were calculated from measurements of ammonia and total Kjeldahl nitrogen, and organic nitrogen loads were estimated using these calculations. Other selected water-quality constituents were monitored for which loads were not calculated. Daily mean load estimates of each constituent were computed by use of a seven-parameter log-linear regression model that uses variables of time, discharge, and seasonality. Concentration of total nitrogen ranged from less than 0.14 to 3.41 mg/L (milligrams per liter), with both extreme values occurring at the Rappahannock River. Concentration of total Kjeldahl nitrogen ranged from less than 0.1 mg/L in the James, Rappahannock, and Appomattox Rivers to 3.0 mg/L in the James River. Organic nitrogen was the predominant form of nitrogen at all stations except the Rappahannock River, where nitrite plus-nitrate nitrogen was predominant, and organic nitrogen comprised the majority of the measured total Kjeldahl nitrogen at all stations, ranging from 0.01 mg/L in the Appomattox River to 2.86 mg/L in the James River. Concentration of dissolved ammonia nitrogen ranged from 0.01 mg/L in the Pamunkey River to 0.54 mg/L at the James River. Concentration of nitrite-plusnitrate nitrogen ranged from 0.02 to 1.05 mg/L in the James River. Concentrations of total phosphorus ranged from less than 0.01 mg/L in the Rappahannock and the Mattaponi Rivers to 1.4 mg/L in the James River. Dissolved orthophosphorus ranged from less than 0.01 mg/L in all five rivers to 0.51 mg/L in the James River. Total suspended solids ranged from a concentration of less than 1 mg/L in all five rivers to 844 mg/L in the Rappahannock River. Total organic carbon ranged from 1.1 mg/L in the Appomattox River to 110 mg/L in the Rappahannock River. Dissolved silica ranged from 2.4 mg/L in the James River to 18 mg/L in the Appomattox River. The James and Rappahannock Rivers had high median concentrations and large ranges in concentrations for most constituents, probably because of a greater number of point and nonpoint sources of nutrients and suspended solids, and differences in land use when compared with the other basins. A significantly higher median concentration and greater range of dissolved orthophosphorus generally occurred at the James River than in all other rivers, which primarily is due to the greater number of point sources, such as municipal waste-water treatment plants. The Rappahannock River had significantly higher median concentrations and greater ranges of dissolved nitrite-plus-nitrate nitrogen and total nitrogen than other rivers, probably derived from agricultural sources. Total organic carbon was highest in the Mattaponi and Pamunkey River Basins that contain expanses of wetlands. The Appomattox River had the highest concentration of dissolved silica. The median monthly load of total nitrogen ranged from 16,500 kg (kilogram) in the Mattaponi River to 371,000 kg in the James River. Total Kjeldahl nitrogen ranged from a median monthly load of 12,500 kg in the Mattaponi River to 205,500 kg, also in the James River. Organic nitrogen comprised the majority of the total Kjeldahl nitrogen load in all five rivers, ranging from a median monthly load of 11,251 kg in the Mattaponi River to 3,299,500 kg in the James River. The median monthly load of dissolved ammonia nitrogen was 1,130 kg in the Mattaponi River and was as much as 21,050 kg in the James River, whereas nitrite-plus-nitrate nitrogen ranged from a median monthly load of 4,065 kg in the Mattaponi River to 156,500 kg in the James River. The median monthly load of total phosphorus ranged from 1,670 kg in the Mattaponi River to 61,600 kg in the James River, whereas the median monthly load of dissolved orthophosphorus ranged from 350 kg in the Mattaponi River to 25,900 kg in the James River. Total suspended solids ranged from a median monthly load of 241,500 kg in the Mattaponi River to 20,050,000 kg in the James River. Total organic carbon ranged from a median monthly load of 167,000 kg in the Mattaponi River to 2,100,000 kg in the James River. The median monthly load of dissolved silica ranged from 209,500 kg in the Mattaponi River to 3,625,000 kg in the James River. In general, annual loads for complete years of data collection were greatest at the James River for all constituents, probably because of the much higher discharge, greater basin size, and higher rates of runoff. Yields, or computations of loads per square mile of basin area, were generally highest at the Rappahannock River for total suspended solids, total Kjeldahl nitrogen, nitrite-plusnitrate nitrogen, and total nitrogen. Dissolved orthophosphorus was the only constituent with a yield consistently greater at the James River. Yields of total phosphorus were highest for the James and Rappahannock River basins, whereas yields of dissolved ammonia nitrogen, total organic carbon, and dissolved silica were similar for all five river basins. Quality-assurance analyses that compare the results of the Virginia Division of Consolidated Laboratory Services and the U.S. Geological Survey Laboratory indicate that there are statistically significant differences between the laboratories for several constituents. Differences between laboratories were found to be caused by differences in analytical reporting limits, differences in analytical technique, or a slight bias at both laboratories. Quality-assurance data were used to address analytical technique problems, and to qualify final concentrations and loads.
Low cost limestone treatment of acid sensitive trout streams in the Appalachian Mountains of Virginia
The method of single point, single application liming has been studied as a means of mitigating anthropogenic acid in trout streams in Virginia. Three critically acid sensitive streams were dosed with a total of five applications of limestone sand and monitored before, during and after the treatments to assess changes in water chemistry and biota. Limestone treatments of 8 to 50 tons (particle sizes 150–1000 μ m), with the amounts based on sulfate deposition loading and existent stream water chemistry, were used to restore ‘lost’ acid neutralizing capacity (ANC). Contact time between the limestone bed in the stream bottom and the water was the limiting factor affecting the degree of treatment with bed length primarily controlled by the gradient of the stream at the dosing site. A single site application was able to restore approximately 2/3 of the ANC. Exponential fits of limestone consumption data were used to predict that treaments of similar streams would last from two five years before reliming was necessary. Both total and monomeric aluminum levels were reduced up to 50%, and aquatic biota increased below the treatment sites. Post-liming average values for the three streams were pH 6.66, 82.7 μ eq L −1 ANC and 2.63 mg L −1 Ca. The average ANC improvement suggests that some 88% of the native trout streams in Virginia, which average 29 μ eq L −1 ANC reduction from acid deposition, could be temporarily restored using single application liming.
Potentiometric surface of the Brightseat-upper Potomac Aquifer in Virginia, 1993
Ground-water level measurements from 30 wells in the Brightseat-upper Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the Brightseat-upper Potomac aquifer indicating a regional trend toward the Chesapeake Bay and Atlantic Ocean. The potentiometric-surface data indicate that cones of depression are apparent around West Point and in southeastern Isle of Wight County near Franklin, Virginia. The highest ground-water-level measurement was 4 feet above sea level in northern Accomack County, and the lowest ground-water-level measurement was 117 feet below sea level in Franklin, Virginia.
Potentiometric surface of the middle Potomac Aquifer in Virginia, 1993
Ground-water level measurements from 50 wells in the middle Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the middle Potomac aquifer sharply declining eastward from nearly 100 feet above sear level near the western boundary of the aquifer to 20 feet below sea level, and continues declining gradually toward the Chesapeake Bay and Atlantic Ocean. A cone of depression is apparent around well fields in Franklin, Virginia. The potentiometric surface also appears to be affected by pumping in the area of Henrico County and Hanover County, Virginia. The highest ground-water-level measurement was 89 feet above sea level in Chesterfield County near Richmond, and the lowest ground-water-level measurement was 179 feet below sea level in southeastern Isle of Wight County, Virginia.
Potentiometric surface of the lower Potomac Aquifer in Virginia, 1993
Ground-water level measurements from 17 wells in the lower Potomac aquifer in the Coastal Plain Physiographic Province of Virginia in 1993 were used to prepare a map of the potentiometric surface of the aquifer. The map shows the potentiometric surface of the lower Potomac aquifer indicating a regional trend toward the Chesapeake Bay and Atlantic Ocean. The potentiometric-surface data indicate that there are two cones of depression, one around well fields in Henrico County and the other around large well fields in Isle of Wight County and Franklin, Virginia. The highest ground-water-level measurement was 47 feet above sea level in southeast Southampton County, and the lowest ground-water-level measurement was 161 feet below sea level in the southeast area of Isle of Wight County near Franklin, Virginia.
Early Paleozoic alkalic and calc-alkalic plutonism and associated contact metamorphism, central Virginia Piedmont
Early Paleozoic plutonism in the central Virginia Piedmont consists of the igneous Lahore Complex and Ellisville Pluton. The Lahore Complex consists of a small altered mafic pluton intruded by the shoshonitic, alkalic monzonites of the Lahore Pluton (-450 Ma) that, in turn, is intruded by the calc-alkaline, granodioritic Ellisville Pluton (-440 Ma). These plutons were emplaced at about 760aC at a depth of 12 to 18 km within greenschist-facies rocks and are enclosed by contact-metamorphosed rocks.
Water resources data, Virginia, water year 1993; Volume 1: Surface-water discharge and surface-water quality records
The Water Resources Division of the U.S. Geological Survey, in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of Virginia each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Virginia."
Water resources data, Virginia, water year 1993; Volume 2: Ground-water level and ground-water quality records
The Water Resources Division of the U.S. Geological Survey, in cooperation with State agencies, obtains a large amount of data pertaining to the water resources of Virginia each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Virginia."
Erysipelothrix rhusiopathiae infection in a captive bald eagle (Haliaeetus leucocephalus)
An adult bald eagle (Haliaeetus leucocephalus) kept in captivity for nearly 7 yr at the Patuxent Wildlife Research Center, Laurel, Maryland, died suddenly with gross and microscopic lesions characteristic of septicemia. Erysipelothrix rhusiopathiae was isolated from the liver. Fish comprised part of the bird's diet and may have been the source of the organism.
Relative effects of nutrient enrichment and grazing on epiphyte-macrophyte (Zostera marina L.) dynamics
The independent and interactive effects of nutrient concentration and epiphyte grazers on epiphyte biomass and macrophyte growth and production were examined in Zostera marina L. (eelgrass) microcosms. Experiments were conducted during early summer, late summer, fall, and spring in a greenhouse on the York River estuary of Chesapeake Bay. Nutrient treatments consisted of ambient or enriched (3× ambient) concentrations of inorganic nitrogen (ammonium nitrate) and phosphate. Grazer treatments consisted of the presence or absence of field densities of isopods, amphipods, and gastropods. epiphyte biomass increased with both grazer removal and nutrient enrichment during summer and spring experiments. The effect of grazers was stronger than that of nutrients. There was little epiphyte response to treatment during the fall, a result possibly of high ambient nutrient concentrations and low grazing pressure. Under low grazer densities of early summer, macrophyte production (g m −2 d −1 ) was reduced by grazer removal and nutrient enrichment independently. Under high grazer densities of late summer, macrophyte production was reduced by enrichment only with grazers absent. During spring and fall there were no macrophyte responses to treatment. The relative influence of epiphytes on macrophyte production may have been related to seasonally changing water temperature and macrophyte requirements for light and inorganic carbon.
Planning and acquiring a national center for the United States Geological Survey
In August 1973, the U.S. Geological Survey moved its first group of employees into the John Wesley Powell Federal Building of its newly constructed National Center at Reston, Virginia. The move signaled the fruition of more than 20 years of dedicated planning and work following World War II, to consolidate the agency's widespread activities into one location, which could truly serve as a national center. Architecture of distinction and quality, in the words of its principal architect, Walter A. Netsch , ''was considered to be quite radical at the time." The John Wesley Powell Federal Building provides requisite and adequate facilities in an architectural style and form which reflect the dignity, enterprise, vigor, and stability of the United States Government. It symbolizes the dedication to the public service that must continue to motivate and guide the Geological Survey. This history of building a National Center for the U.S. Geological Survey is a "nuts and bolts" account of the planning, design and construction, forgotten happenings, and frustrations in the planning and authorization process, and the political and other considerations which played a significant role in the culmination of a dream about a National Center for the Geological Survey. This documented data of unique procedures in the acquisition and financing of Federal buildings, the choice and development of the building site, and its location as a contribution to the enhancement of the "new town" concept of the 1960's in the planning and development of the National Capital Area, may well provide guidance in the future to those who have to decide whether a building of true worth should be preserved.
Landslides triggered by the storm of November 3-5, 1985, Wills Mountain Anticline, West Virginia and Virginia
More than 3,000 landslides were triggered by heavy rainfall in the central Appalachian Mountains of West Virginia and Virginia, November 3-5, 1985. These landslides provided the opportunity to study spatial controls on landslides, magnitude and frequency of triggering events, and the effects of landslides on flood-induced geomorphic change. The study area consists of parts of the Wills Mountain anticline, a major NE-trending structure in the central Appalachians, and a portion of the adjacent Appalachian Plateau. Across the anticline and adjacent plateau, bedrock lithologies vary markedly and include pure marine limestone, marine shale, deltaic mudstone/sandstone sequences, and orthoquartzites. Because of the geologic structure, bedrock lithology varies little along strike. The spatial distribution of landslides triggered by the storm was controlled primarily by rainfall, bedrock lithology, surficial lithology, land cover, and slope morphology. The triggering rainfall was of moderate intensity and long duration. Two-day storm totals varied from 170 mm to more than 240 mm in the study area. Most landslides occurred at the northeast end of the study area, where 48-h rainfall totals were in excess of 200 mm. Different rainfall thresholds are apparent for triggering landslides on different bedrock lithologies. The highest density of landslides occurred in shallow colluvium and residuum of the Reedsville Shale (Ordovician), followed by regolith of the Greenbriar and Mauch Chunk Groups (Mississippian). Most of the landslides in these fine-grained regoliths were shallow slides and slumps, many of which transformed to mudflows and delivered sediment directly to streams; a smaller number of debris avalanches were triggered high on quartzite ridges. Instability of colluvium and residuum derived from the Reedsville Shale, compared with regolith from four other fine-grained bedrock lithologies, is attributable to its low strength combined with moderate infiltration rates that allowed soil moisture to accumulate under the moderate intensities of the rainfall. Slopes covered by coarse, cobbly debris flow and alluvial deposits, mostly of Pleistocene age, were very stable due to their low slope angles and high frictional strength. For a particular bedrock lithology, the spatial distribution of landslides appears controlled by interdependent influences of slope morphology and land cover. On the Reedsville Shale, most landslides occurred on north- to northeast-facing slopes, which might have had higher antecedent levels of soil moisture; these slopes have also been preferentially cleared because they produce better pasture forage for livestock. A secondary concentration of landslides on south- to southwest-facing slopes cannot be explained by conventional soil-moisture models. Landslide density was 100--200 percent higher on cleared land than on forested land. On pastured land, most landslides occurred on laterally planar slopes, but on forested land, most landslides occurred in slope positions that were laterally concave (hillslope hollows). Compared with other documented Appalachian storms that have triggered landslides, the November 1985 storm had lower rainfall intensities over longer durations. Comparison with these other storms suggests that the anomalously high degree of slope instability in 1985 is due to the long duration of low-intensity rainfall on fine-grained regolith derived from shale; the triggering rainfall can be approximated by the 48-h storm total. Landslide density in Reedsville Shale regolith is linearly related to the varying 48-h rainfall along the anticline. These data define a probabilistic model that estimates return intervals of 43 to 300 yr for landslide densities ranging from 1 to 70 landslides/km 2 . Analysis of flood-induced geomorphic changes in 79 small drainage basins that received 210-240 mm of rainfall showed a clear local association between landslides and channel erosion or deposition adjacent to where the landslides delivered sediment to the stream. When channel change was quantified using an index evaluated at each basin mouth, most of the channel change was attributable to the influence of basin morphology on flood discharge. Landslide density in the basins was of secondary, although measurable, importance in explaining flood-induced channel changes at the basin scale.