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Geology topics

Thomas C. Winter

Publications and source records attributed to Thomas C. Winter.

At least 19 recordsLinked to original sources
USGS2013

Physical, chemical, and isotopic data from groundwater in the watershed of Mirror Lake, and in the vicinity of Hubbard Brook, near West Thornton, New Hampshire, 1983 to 1997

Research on the hydrogeologic setting of Mirror Lake near West Thornton, New Hampshire (43° 56.5’ N, 71° 41.5’ W), includes the study of the physical, chemical, and isotopic characteristics of groundwater in the vicinity of the lake and nearby Hubbard Brook. Presented here are those physical, chemical, and isotopic data for the period 1983 to 1997. Data were collected from observation wells installed in glacial drift and bedrock, as well as from one domestic well in the general area of the lake and Hubbard Brook. Also presented are data for Mirror Lake for August 1, 1993, to place groundwater data in context with chemical and isotopic characteristics of the lake.

New Hampshire↗
USGS2012

Recent advances in understanding the interaction of groundwater and surface water

The most common image of the interaction of groundwater and surface water is that of the interaction of streams with a contiguous alluvial aquifer. This type of system has been the focus of study for more than 100 years, from the work of Boussinesq (1877) to the present, and stream-aquifer interaction continues to be the most common topic of papers discussing the interaction of groundwater and surface water. However, groundwater and surface water interact in a wide variety of landscapes from alpine to coastal. Within these landscapes, ground-water systems range in scale from local to regional, and the types of surface water include streams, lakes, wetlands, and oceans. Given the broad spectrum of the topic of groundwater and surface water interaction, an overview of studies of this topic could be organized according to surface water type, landscape type, scale of hydrologic systems, or field and analytical methods. All these factors are discussed, but this paper is organized according to landscape type because of the great increase in studies of the interaction of groundwater and surface water in landscapes other than riverine systems in the last 15 years. Furthermore, discussing studies by landscape type facilitates comparison of methods and results from different geologic and climatic settings. The general landscapes discussed are mountain terrane, riverine systems, coastal terrane, hummocky terrane, and karst terrane.

Reviews of Geophysics↗
USGS2011

Paleohydrologic phenomena recorded by lake sediments

Hydrologic phenomena are dynamic, so their understanding and prediction are difficult and challenging. Many are cyclic, ranging from diurnal, seasonal, and annual cycles to climatic fluctuations of many hundreds or thousands of years. Predicting the magnitude and recurrence intervals of long-term fluctuations of these phenomena is a primary concern of hydrologists. The best data upon which to base predictions are those that directly measure a hydrologic phenomenon, such as stream discharge, lake level, and precipitation. Programs for collection of these data over a large area on a scientific basis, however, are less than 100 years old-not a very sound statistical base for predicting events that have recurrence intervals of at least that long.

Earth and Space Science↗
USGS2010

Evaluation of 11 equations for determining evaporation for a small lake in the North Central United States

Eleven equations for calculating evaporation were compared with evaporation determined by the energy budget method for Williams Lake, Minnesota. Data were obtained from instruments on a raft, on land near the lake, and at a weather station 60 km south of the lake. The comparisons were based on monthly values for the open-water periods of 5 years, a total of 22 months. A modified DeBruin-Keijman, Priestley-Taylor, and a modified Penman equation resulted in monthly evaporation values that agreed most closely with energy budget values. To use these equations, net radiation, air temperature, wind speed, and relative humidity need to be measured near the lake. In addition, thermal surveys need to be made to determine change in heat stored in the lake. If data from distant climate stations are the only data available, and they include solar radiation, the Jensen-Haise and Makkink equations resulted in monthly evaporation values that agreed reasonably well with energy budget values.

Minnesota↗
USGS2010

An approach to the design of statewide or regional ground water information systems

The design of water information or basic data systems must be flexible enough to provide information and data for a broad range of interests from national to local. The system must satisfy the need for information for accounting, surveillance, and areal synthesis purposes. The network is designed by identifying specific needs in terms of maps, analyses, and studies that will provide the basic knowledge for understanding each particular phase of the groundwater system. Each specific need is then analyzed with respect to whether it will provide information on accounting, surveillance, or areal synthesis. If a particular type of map, analysis, or observation can serve any of these three functions, a network of data collection or a program of studies is outlined in detail that will provide the information needed. The method of design necessitates the establishment of accuracy levels for maps, the density of data points, confidence limits, and so forth. The information system should be under the general guidance of a single agency, but much of the work and responsibility to carry out the details of the system must be shared by a number of agencies.

Water Resources Research↗
USGS2010

Classification of the hydrologic settings of lakes in the north central United States

The hydrologic settings of 150 lakes in the north central United States were investigated by principal component analysis as a first attempt to develop a general classification of the hydrologic settings of lakes. Precipitation-evaporation balance and the water quality variables have high loadings on the first principal component. Highest loadings on component 2 are for streamflow in and out of the lakes. Components 3 and 4 are characterized by geologic and groundwater flow variables. The drainage basin area/lake area ratio, the overland runoff variable, has the highest loading on component 5. The stability of the principal components was tested by randomly splitting the data and comparing a principal component analysis of each subsample. This showed the first two principal components to be the most stable. The components described by the groundwater variables are less stable, but there is justification for using them with caution. Of the variables examined in this study the distribution of dissolved solids of groundwater is most closely related to the distribution of lake types as determined by other limnological typologies in the north central United States. The study indicates that the following are the most important variables to be considered in classifying the hydrologic settings of lakes: dissolved solids concentration of groundwater, precipitation-evaporation balance, streamflow inlet and outlet, the ratio of drainage basin area to lake area, and lake depth. Of the groundwater variables, local relief and regional slope are more important than is regional position. Texture of the drift and bedrock, which is related to hydraulic conductivity of the rocks, is very important.

Water Resources Research↗
USGS2010

Numerical simulation of steady state three-dimensional groundwater flow near lakes

Numerical simulation of three-dimensional groundwater flow near lakes shows that the continuity of the boundary encompassing the local groundwater flow system associated with a lake is the key to understanding the interaction of a lake with the groundwater system. The continuity of the boundary can be determined by the presence of a stagnation zone coinciding with the side of the lake nearest the downgradient side of the groundwater system. For most settings modeled in this study the stagnation zone underlies the lakeshore, and it generally follows its curvature. The length of the stagnation zone is controlled by the geometry of the lake's drainage basin divide on the side of the lake nearest the downgradient side of the groundwater system. In the case of lakes that lose water to the groundwater system, three-dimensional modeling also allows for estimating the area of lake bed through which outseepage takes place. Analysis of the effects of size and lateral and vertical distribution of aquifers within the groundwater system on the outseepage from lakes shows that the position of the center point of the aquifer relative to the littoral zone on the side of the lake nearest the downgradient side of the groundwater system is a critical factor. If the center point is downslope from this part of the littoral zone, the local flow system boundary tends to be weak or outseepage occurs. If the center point is upslope from this littoral zone, the stagnation zone tends to be stronger (to have a higher head in relation to lake level), and outseepage is unlikely to occur.

Water Resources Research↗
USGS2010

Quantification of surface water and groundwater flows to open‐ and closed‐basin lakes in a headwaters watershed using a descriptive oxygen stable isotope model

Accurate quantification of hydrologic fluxes in lakes is important to resource management and for placing hydrologic solute flux in an appropriate biogeochemical context. Water stable isotopes can be used to describe water movements, but they are typically only effective in lakes with long water residence times. We developed a descriptive time series model of lake surface water oxygen‐18 stable isotope signature ( δL ) that was equally useful in open‐ and closed‐basin lakes with very different hydrologic residence times. The model was applied to six lakes, including two closed‐basin lakes and four lakes arranged in a chain connected by a river, located in a headwaters watershed. Groundwater discharge was calculated by manual optimization, and other hydrologic flows were constrained by measured values including precipitation, evaporation, and streamflow at several stream gages. Modeled and observed δL were highly correlated in all lakes ( r = 0.84–0.98), suggesting that the model adequately described δL in these lakes. Average modeled stream discharge at two points along the river, 16,000 and 11,800 m 3 d −1 , compares favorably with synoptic measurement of stream discharge at these sites, 17,600 and 13,700 m 3 d −1 , respectively. Water yields in this watershed were much higher, 0.23–0.45 m, than water yields calculated from gaged streamflow in regional rivers, approximately 0.10 m, suggesting that regional groundwater discharge supports water flux through these headwaters lakes. Sensitivity and robustness analyses also emphasized the importance of considering hydrologic residence time when designing a sampling protocol for stable isotope use in lake hydrology studies.

Water Resources Research↗
USGS2009

Hydrologic processes and the water budget: Chapter 2

This chapter focuses on the hydrological setting of Mirror Lake and its water budget. It first describes the glacial deposits and bedrock topography in the Mirror Lake area. It then provides an overview of the hydrologic processes associated with Mirror Lake and examines the field and analytical methods used to determine its water budget. It presents results from the hydrologic studies, which are based on monthly and annual water budgets for the calendar years 1981 through 2000.

New Hampshire↗
USGS2009

Evaluation of methods and uncertainties in the water budget

Water budget studies of Mirror Lake aim to measure hydrologic components interacting with the lake as accurately as possible. However, measurements of water budget components are subject to some degree of uncertainty. This chapter describes the methods used to quantify water budget components of Mirror Lake in detail. It examines uncertainties in precipitation values, monthly evaporation, water flows, and exchange with groundwater. It shows how those values were derived, including the assumptions that went into the calculations and the uncertainties inherent in the values.

New Hampshire↗
USGS2007

Comparison of 15 evaporation methods applied to a small mountain lake in the northeastern USA

Few detailed evaporation studies exist for small lakes or reservoirs in mountainous settings. A detailed evaporation study was conducted at Mirror Lake, a 0.15 km2 lake in New Hampshire, northeastern USA, as part of a long-term investigation of lake hydrology. Evaporation was determined using 14 alternate evaporation methods during six open-water seasons and compared with values from the Bowen-ratio energy-budget (BREB) method, considered the standard. Values from the Priestley-Taylor, deBruin-Keijman, and Penman methods compared most favorably with BREB-determined values. Differences from BREB values averaged 0.19, 0.27, and 0.20 mm d-1, respectively, and results were within 20% of BREB values during more than 90% of the 37 monthly comparison periods. All three methods require measurement of net radiation, air temperature, change in heat stored in the lake, and vapor pressure, making them relatively data intensive. Several of the methods had substantial bias when compared with BREB values and were subsequently modified to eliminate bias. Methods that rely only on measurement of air temperature, or air temperature and solar radiation, were relatively cost-effective options for measuring evaporation at this small New England lake, outperforming some methods that require measurement of a greater number of variables. It is likely that the atmosphere above Mirror Lake was affected by occasional formation of separation eddies on the lee side of nearby high terrain, although those influences do not appear to be significant to measured evaporation from the lake when averaged over monthly periods.

New Hampshire↗
USGS2007

Water Budgets: Foundations for Effective Water-Resources and Environmental Management

INTRODUCTION Water budgets provide a means for evaluating availability and sustainability of a water supply. A water budget simply states that the rate of change in water stored in an area, such as a watershed, is balanced by the rate at which water flows into and out of the area. An understanding of water budgets and underlying hydrologic processes provides a foundation for effective water-resource and environmental planning and management. Observed changes in water budgets of an area over time can be used to assess the effects of climate variability and human activities on water resources. Comparison of water budgets from different areas allows the effects of factors such as geology, soils, vegetation, and land use on the hydrologic cycle to be quantified. Human activities affect the natural hydrologic cycle in many ways. Modifications of the land to accommodate agriculture, such as installation of drainage and irrigation systems, alter infiltration, runoff, evaporation, and plant transpiration rates. Buildings, roads, and parking lots in urban areas tend to increase runoff and decrease infiltration. Dams reduce flooding in many areas. Water budgets provide a basis for assessing how a natural or human-induced change in one part of the hydrologic cycle may affect other aspects of the cycle. This report provides an overview and qualitative description of water budgets as foundations for effective water-resources and environmental management of freshwater hydrologic systems. Perhaps of most interest to the hydrologic community, the concepts presented are also relevant to the fields of agriculture, atmospheric studies, meteorology, climatology, ecology, limnology, mining, water supply, flood control, reservoir management, wetland studies, pollution control, and other areas of science, society, and industry. The first part of the report describes water storage and movement in the atmosphere, on land surface, and in the subsurface, as well as water exchange among these compartments. Our ability to measure these phenomena and inherent uncertainties in measurement techniques also are discussed. The latter part of the report presents a number of case studies that illustrate how water-budget studies are conducted, documents how human activities affect water budgets, and describes how water budgets are used to address water and environmental issues.

Circular↗
USGS2006

The significance of ground water to the accumulation of iron and manganese in the sediments of two hydrologically distinct lakes in north‐central Minnesota: A geological perspective

Williams and Shingobee lakes are at opposite ends of the local ground water flow system in the Shingobee River Headwaters Area (SRHA) in north‐central Minnesota. Williams Lake, situated near the highest point in the flow system, has no surface inlet or outlet, and ground water and precipitation are the only sources of water. Shingobee Lake, situated at the lowest point in the flow system, has the Shingobee River as an inlet and outlet. Ground water directly contributes an estimated one‐fourth of the water input to Shingobee Lake. The Shingobee River also receives large amounts of ground water discharge along its reach to Shingobee Lake providing a large, indirect source of ground water to the lake. Differences in nutrient concentrations reflect the residence times and nutrient supplies of these two lakes. The average phosphorus content of Shingobee Lake is about twice that of Williams Lake. Consequently, phy‐toplankton productivity in Shingobee Lake is much higher than in Williams Lake, leading to an oxygen‐deficient (<1 ppm dissolved oxygen) hypolimnion within a month after overturn in both the spring and fall. Because of the extreme reducing conditions in the hypolimnion of Shingobee Lake, high concentrations of dissolved iron and manganese are present there during summer stratification. In some years, the manganese concentration in the hypolimnion of Shingobee Lake remains high throughout the year. Precipitation of iron and manganese minerals, presumed to be X‐ray amorphous oxyhydroxides, at periods of fall and spring overturn result in concentrations of iron and manganese in surface sediments of Shingobee Lake that are seven times and 27 times higher, respectively, than can be explained by contributions of iron and manganese from detrital aluminosilicates. These findings indicate that the source and amounts of this excess iron and manganese found in the sediments are correlated to the amount of iron‐ and manganese‐rich ground water discharging to Shingobee Lake. Because iron and manganese oxyhydroxides are efficient adsorbers of phosphorus, concentrations of phosphorus are also high in the sediments of Shingobee Lake. Without this sequestration of phosphorus, the productivity of Shingobee Lake would probably be much higher.

North-central Minnestoa↗
USGS2005

Estimating ground-water recharge from streamflow hydrographs for a small mountain watershed in a temperate humid climate, New Hampshire, USA

Hydrographs of stream discharge were analyzed to determine ground-water recharge for two small basins draining into Mirror Lake, New Hampshire. Two methods of hydrograph analysis developed for determining ground-water recharge were evaluated, the instantaneous recharge method and the constant recharge method. For the instantaneous recharge method, recharge is assumed to be instantaneous and uniform over the basin. For the constant recharge method, recharge is assumed to be constant and uniform over the basin for a period of weeks to months. Both methods require that a ground-water recession slope be determined. The recession slope is used directly in the calculation for the instantaneous recharge method, and it is used as a base of reference for fitting a type curve in the constant recharge method. Results of the study indicated that the estimates of ground-water recharge for both methods agree to within about 10 percent. Two approaches to the instantaneous recharge method, manual and automated, were also evaluated, and the results were statistically similar. The baseflow component of streamflow commonly is assumed to be equivalent to ground-water recharge; therefore, two methods developed for determining the baseflow component of streamflow, graphical partitioning and digital filtering, were evaluated also. Baseflow values determined by graphical partitioning of hydrographs were about 25 percent less than the ground-water recharge values. Baseflow values determined by two different approaches to the mathematical digital filtering method were generally less than baseflow determined by graphical partitioning. However, one of the approaches to digital filtering agreed reasonably well with graphical partitioning if an appropriate filter constant was used. The other approach to digital filtering resulted in baseflow values that were much less than the other baseflow values and was therefore deemed inappropriate for use on these small mountain watersheds.

Groundwater↗
USGS2004

Delineation and evaluation of hydrologic-landscape regions in the United States using geographic information system tools and multivariate statistical analyses.

Hydrologic-landscape regions in the United States were delineated by using geographic information system (GIS) tools combined with principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting of 43,931 small (approximately 200 km 2 ) watersheds in the United States. (The term “watersheds” is defined in this paper as the drainage areas of tributary streams, headwater streams, and stream segments lying between two confluences.) The analyses grouped the watersheds into 20 noncontiguous regions based on similarities in land-surface form, geologic texture, and climate characteristics. The percentage of explained variance (R-squared value) in an analysis of variance was used to compare the hydrologic-landscape regions to 19 square geometric regions and the 21 U.S. Environmental Protection Agency level-II ecoregions. Hydrologic-landscape regions generally were better than ecoregions at delineating regions of distinct land-surface form and geologic texture. Hydrologic-landscape regions and ecoregions were equally effective at defining regions in terms of climate, land cover, and water-quality characteristics. For about half of the landscape, climate, and water-quality characteristics, the R-squared values of square geometric regions were as high as hydrologic-landscape regions or ecoregions.

Environmental Management↗
USGS2004

Estimates of fetch-induced errors in Bowen-ratio energy-budget measurements of evapotranspiration from a prairie wetland, Cottonwood Lake Area, North Dakota, USA

Micrometeorological measurements of evapotranspiration ( ET ) often are affected to some degree by errors arising from limited fetch. A recently developed model was used to estimate fetch-induced errors in Bowen-ratio energy-budget measurements of ET made at a small wetland with fetch-to-height ratios ranging from 34 to 49. Estimated errors were small, averaging −1.90%±0.59%. The small errors are attributed primarily to the near-zero lower sensor height, and the negative bias reflects the greater Bowen ratios of the drier surrounding upland. Some of the variables and parameters affecting the error were not measured, but instead are estimated. A sensitivity analysis indicates that the uncertainty arising from these estimates is small. In general, fetch-induced error in measured wetland ET increases with decreasing fetch-to-height ratio, with increasing aridity and with increasing atmospheric stability over the wetland. Occurrence of standing water at a site is likely to increase the appropriate time step of data integration, for a given level of accuracy. Occurrence of extensive open water can increase accuracy or decrease the required fetch by allowing the lower sensor to be placed at the water surface. If fetch is highly variable and fetch-induced errors are significant, the variables affecting fetch (e.g., wind direction, water level) need to be measured. Fetch-induced error during the non-growing season may be greater or smaller than during the growing season, depending on how seasonal changes affect both the wetland and upland at a site.

North Dakota↗
USGS2003

The design and use of a hydraulic potentiomanometer for direct measurement of differences in hydraulic head between groundwater and surface water

The hydraulic potentiomanometer described herein consists of a potentiometer connected to a manometer by a flexible tube. The device is used to directly measure the direction of seepage as well as the hydraulic-head difference between groundwater and surface water. The device works most effectively in sandy materials. For accurate measurements the device must be free of air leaks.

Limnology and Oceanography↗