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USGS1997

Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency lakes, Oregon

Upper Klamath Lake and the connecting Agency Lake constitute a large, shallow lake in south-central Oregon that the historical record indicates has likely been eutrophic since its discovery by non-Native Americans. In recent decades, however, the lake has had annual occurrences of near-monoculture blooms of the blue-green alga Aphanizomenon flos-aquae that are thought to be a result of accelerated eutrophication. In 1988, two sucker species endemic to the lake, the Lost River sucker ( Deltistes luxatus ) and the shortnose sucker ( Chasmistes brevirostris ), were listed as endangered by the U.S. Fish and Wildlife Service, and it has been proposed that their decline is due to the poor water quality associated with extremely long and productive algal blooms. It has also been proposed that the effluent drained from wetlands has contributed to accelerated eutrophication. Since the turn of century, most of the wetlands adjacent to Upper Klamath Lake have been drained for agriculture--cultivation of crops and grazing of cattle. Wetland areas were reclaimed from the lake by building dikes to isolate them from the lake, constructing a series of drainage ditches, and installing pumps to drain the water and maintain a lowered water table. A consequence of lowering the water table is the increased ability of air and oxygenated water to move through the subsurface and facilitate the rapid aerobic decomposition of the peat soils. Nutrients, nitrogen and phosphorus, are then liberated, leach into adjacent ditches, and are subsequently pumped to the lake or its tributaries. The rate of peat decomposition may be related to the time since drainage and the type of agricultural land use. On lands cultivated for crops, farming practices, such as disking and furrowing, could enhance the movement of air and oxygenated water, resulting in a rapid rate of decomposition. In contrast, on grazed lands, the compaction of soils by cattle probably inhibits the movement of air and oxygenated water and results in a slower rate of decomposition relative to drained wetlands used for the cultivation of crops. This report presents the results of a cooperative study between the U.S. Geological Survey and the Bureau of Reclamation whose overall objective was to determine the nutrient loading to Upper Klamath Lake from adjacent drained wetlands. Nutrient loading from drained wetlands was estimated using two independent techniques. The first method involved the measurement of the quantity and quality of water discharged by pumps draining the wetlands. The second method was used to estimate the initial (before drainage) and present-day nutrient mass of the organic soils within the drained wetlands and to calculate the change (or loss) in nutrient mass. In an effort to estimate the nutrient contributions from the water pumped off selected drained wetlands adjacent to Upper Klamath Lake, annual loads and yields of total nitrogen and total phosphorus were estimated from concentration data and the volume of water pumped during the water year. In general, there was little variation among sites or among years in the annual total nitrogen (median load of about 18 tons per year and median yield of about 8 pounds per acre per year) or the annual total phosphorus (median load of about 3 tons per year and median yield of about 2 pounds per acre per year) contributions. The sum of the annual loads of nitrogen and phosphorus calculated for each of the pumping stations in 1995 was 80 tons per year and 15 tons per year, respectively. In 1995, soil-coring activities were undertaken to ascertain the nature and extent of the organic soils in the drained and undrained wetlands. The present-day nutrient mass was calculated for each drained wetland using the nutrient content (concentration) and the present-day peat mass. The initial nutrient mass prior to drainage was estimated for each drained wetland by using the initial nutrient content (assumed to be equal to the nutrient content of the undrained wetlands) and the initial peat mass as determined using the amount of accumulated decomposition residue. The cumulative loss of nutrient mass since drainage was calculated as the change between initial and present-day nutrient mass for each drained area. The cumulative yield of total nitrogen and total phosphorus loss from the organic soils of individual wetlands since drainage ranged from 3,000 to 70,000 pounds per acre and from 0 to 1,300 pounds per acre, respectively. For all the drained wetlands sampled, the cumulative nitrogen and phosphorus loss since drainage totaled 250,000 tons and 4,300 tons, respectively. This represents about 30 percent and 22 percent of the mass of nitrogen and phosphorus, respectively, that initially existed in the organic soils. The loss of nutrients from the drained wetlands is considered to be a maximum estimate of the possible contribution of nutrients to Upper Klamath Lake from the peat soils of the drained wetlands sampled. However, not all the nutrients released by the soils are discharged to the lake. Nutrients lost from the peat soils of the drained wetlands may have been taken up by crops and harvested or consumed by grazing cattle. In addition, nitrogen can be lost to the atmosphere by denitrification and the volatilization of ammonia; phosphorus may be bound to adjacent soil layers by adsorption. The annual nutrient loss for the period 1994–95 was calculated using a first-order rate law to describe nutrient loss since drainage began. For individual drained wetlands, the yield of nitrogen and phosphorus lost from the organic soils for the period 1994–95 ranged from 27 to 540 pounds per acre per year and from 0 to 15 pounds per acre per year, respectively. The total mass of nitrogen and phosphorus loss during this period was 3,000 tons per year and 60 tons per year, respectively, for all drained wetlands that were sampled. The yield and mass of nutrient loss determined in this fashion reflect what might be expected on the basis of time-averaged or longterm contributions of nutrients to the lake and do not reflect the specific conditions existing during the period 1994–95. The results of this study could be useful in helping to prioritize which drained wetlands may provide the greatest benefits with regard to reducing nutrient loads to the lake if restoration or land-use modifications are instituted. Recent acquisition and planned restoration of drained wetland areas at the Wood River and Williamson River North properties may produce significant reduction in the quantity of nutrients released by the decomposition of peat soils of these areas. If the water table rises to predrainage levels, the peats soils may become inundated most of the year, resulting in the continued long-term storage of nutrients within the peat soils by reducing aerobic decomposition. The maximum benefit, in terms of decreasing potential nutrient loss due to peat decomposition, could be the reduction of total nitrogen and total phosphorus loss to about one-half that of the 1994–95 annual loss estimated for all the drained wetlands sampled for this study.

Oregon↗

USGS2019

Demonstrating the value of Earth observations—methods, practical applications, and solutions—group on Earth observations side event proceedings

Executive Summary The U.S. Geological Survey, the National Oceanic and Atmospheric Administration, the European Association for Remote Sensing Companies, and the European Space Agency in coordination with the GEOValue Community hosted a side event to the Group on Earth Observations Plenary on October 23–24, 2017, in Washington, D.C. The workshop, entitled “Demonstrating the Value of Earth Observations: Methods, Practical Applications and Solutions,” brought together more than 60 international experts including economists, scientists, and engineers to consider the state of the science and applications of valuing Earth observations (EO). This 2-day workshop built upon previous activities developed under the GEOValue initiative. This workshop brought together expert analysts from multiple disciplines and backgrounds who are developing methods to identify and measure the value of information generated from the use of satellite and in-situ data. The mix of government agencies, international financial institutions, and independent consultants who participated in the workshop blended to develop a rich mix of views, approaches, and outcomes. During the first part of the workshop, the focus was on the latest science in valuing EO. A number of methodologies were described. Approaches generally assess the societal benefits of specific actions (for example, investments in EO). Some methods focus on broad measures of economic activity (for example, gross domestic product) or methods to assess total economic value such as contingent valuation surveys. Alternatively, use-case approaches (a use case is defined as an evaluation in which one or more decisions, applications, or other uses of data, information, and information products are specifically considered) start with the specific actions and how information is used to support decision making and affect outcomes. The second part of the meeting was focused on the use and development of value chains and decision trees. A value chain can be defined as the set of value-adding activities that one or more organizations perform in creating and distributing goods and services. In terms of EO, the value chain approach can be applied to consider societal benefits of the data and assess the value of data and data features. The EO value chain considers the geospatial data sources and the processing of the data into value added information to be incorporated into decision-support systems, leading to decision makers’ actions. To understand the value of EO, one would also need to recognize the demand side of the equation or how EO benefits users. Extending the value chain concept and incorporating tenets of Bayesian decision making, a decision tree would include one or more use cases. The value provided by the marginal increase in information could flow from one or several parts of the supply side of the value chain. The decision tree is based on the premise that information has no value if it is not used in at least one decision. By connecting the value chain and the decision tree, a framework is created that allows for conceptualizing the value of EO in its many uses. One can then apply economic techniques to monetize the marginal benefit of an outcome with information versus one without. A third part of the meeting applied the value chain and decision-tree frameworks to five specific thematic areas, each with the focus of using information for a decision point: Effect of increasing temperatures on human health; Flooding—Mitigating, managing, and avoiding impacts to safety and property damage; Harmful algal blooms—Effects on human health, recreation, and tourism; Energy and mineral supply—Mitigating, managing, and avoiding impacts of shortfalls on the economy; and Effects of natural hazards on transportation systems—Effects on mobility, safety, and the economy. During the working session, five separate groups worked to define and delineate the value chains and decision trees associated with each topic, discussing the related challenges and data needs. The outcomes were reported back to the full group. Because of the complexity of the topics, most groups first identified a network of value chains and then narrowed the scope to develop a single value chain to address their group’s topic. Although they worked separately and on different topics, the groups came to similar conclusions, concurring that the value chain and decision-tree frameworks are very effective for informing quantitative impact assessments and developing a relatable narrative to assist the public in understanding the link between EO and citizens.

Open-File Report↗

USGS2012

TracerLPM (Version 1): An Excel® workbook for interpreting groundwater age distributions from environmental tracer data

TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one point in time; however, prior knowledge of an appropriate LPM is required because the mean age is often non-unique. LPM output concentrations depend on model parameters and sample date. All of the LPMs have a parameter for mean age. The EPM, PEM, and DM have an additional parameter that characterizes the degree of age mixing in the sample. BMMs have a parameter for the fraction of the first component in the mixture. An LPM, together with its parameter values, provides a description of the age distribution or the fractional contribution of water for every age of recharge contained within a sample. For the PFM, the age distribution is a unit pulse at one distinct age. For the other LPMs, the age distribution can be much broader and span decades, centuries, millennia, or more. For a sample with a mixture of groundwater ages, the reported interpretation of tracer data includes the LPM name, the mean age, and the values of any other independent model parameters. TracerLPM also can be used for simulating the responses of wells, springs, streams, or other groundwater discharge receptors to nonpoint-source contaminants that are introduced in recharge, such as nitrate. This is done by combining an LPM or user-defined age distribution with information on contaminant loading at the water table. Information on historic contaminant loading can be used to help evaluate a model's ability to match real world conditions and understand observed contaminant trends, while information on future contaminant loading scenarios can be used to forecast potential contaminant trends.

Techniques and Methods↗

USGS2024

Volcanic gas monitoring

Introduction As magma rises through the crust, decreasing pressure conditions allow volatiles to exsolve from the magma. These volatiles then migrate upward through the crust, where they can be stored at shallower levels or escape to the atmosphere. Rising magma also heats rock masses beneath volcanic centers, causing water in shallow aquifers and hydrothermal systems to boil and release additional gases and steam (see chapter F , this volume; Ingebritsen and Hurwitz, 2024). The chemistry and quantity of gases that reach the surface during periods of quiescence or volcanic unrest can reveal that gas-rich magma is ascending, crystallizing, or alternatively stalling, with important implications for volcanic hazard (for example, Sutton and others, 1992; Aiuppa and others, 2007, 2021; Werner and others, 2009, 2011, 2012; Moretti and others, 2013; de Moor and others, 2016; Lewicki and others, 2019; Edmonds and others, 2022; Kern and others, 2022; Kunrat and others, 2022). Most volcanoes in Alaska and the western United States are characterized by weak degassing, with one or more low-temperature fumaroles (typically near the local boiling temperature of water) and connect to a deeper and sometimes extensive hydrothermal system (for example, McGee and others, 2001; Symonds and others, 2003a, b). Hydrothermal systems will affect the chemistry of rising gases exsolved from deeper magma (Symonds and others, 2001), including sulfur dioxide (SO 2 ), hydrogen chloride (HCl), and water vapor (for example, Doukas and Gerlach, 1995; Gerlach and others, 1998, 2008; Symonds and others, 2001; Werner and others, 2013). As an example, depending on factors such as temperature, pressure, and oxidation state, rising SO 2 will react with groundwater to form hydrogen sulfide (H 2 S) gas, dissolved sulfate (SO 4 2− ), or elemental sulfur (Christenson, 2000; Symonds and others, 2001; Werner and others, 2008). The reaction and dissolution of SO 2 into shallow groundwater is commonly referred to as scrubbing, and can reduce the likelihood that ascending, degassing magma can be detected. Carbon dioxide, however, in addition to exsolving from magma early in the ascent process, is not easily removed by hydrothermal fluids (Lowenstern, 2001). As scrubbing and other processes take place, the SO 2 /H 2 S, CO 2 /SO 2 , and CO 2 /H 2 S ratios may change. High rates of SO 2 emission indicate that magma has moved to relatively shallow levels in the volcano and that the system has heated up enough to establish dry pathways from depth to the surface. Monitoring multiple gas species and the total output of those species is thereby useful for volcano monitoring during both periods of quiescence, to establish background degassing conditions, and during unrest, when gas geochemistry and emission rates can provide information on changing conditions, such as magma ascent. To provide context for multidisciplinary volcano forecasts, we focus on the following two key required capabilities: (1) characterizing baseline geochemistry and gas discharge from volcanoes and volcanic regions and (2) monitoring changes in gas geochemistry and discharge to inform forecasts of volcanic eruptions and their effects. Sufficient baseline data must be collected to identify and interpret anomalous degassing associated with volcanic unrest (for example, Sorey and others, 1998; Rouwet and others, 2014). Differences in volcano type, baseline degassing rates, local hydrology, and geography (for example, high versus low latitude) will result in a different baseline for each volcano. Volcanoes of any threat level that exhibit one or more degassing phenomena would ideally be monitored by techniques needed to establish baseline degassing data, with the sampling frequency of baseline data dictated by the threat level (table E1). Additional monitoring techniques become necessary during periods of unrest. In general, three of the most important techniques for gas monitoring are (1) direct sampling of fumarole, spring, and soil gases for laboratory geochemical measurements, (2) measurements of the chemical composition of the volcanic plume and emission rates of major gas species (for example, H 2 O, CO 2 , SO 2 , and H 2 S) by satellite, airborne, or ground-based techniques, and (3) measurements of diffuse emissions of CO 2 and other gases through soils. Various methods and instruments may be useful both for baseline studies and during unrest.

Scientific Investigations Report↗

USGS1989

Results of hydrologic research at a low-level radioactive-waste disposal site near Sheffield, Illinois

Ten years of hydrologic research have been conducted by the U.S. Geological Survey at a commercial low-level radioactive-waste disposal site near Sheffield, Illinois. Research included studies of microclimate, evapotranspiration, and tritium release by plants; runoff and land modification; water movement through a trench cover; water and tritium movement in the unsaturated zone; gases in the unsaturated zone; water and tritium movement in the saturated zone; and water chemistry. Implications specific to each research topic and those based on overlapping research topics are summarized as to their potential effect on the selection, characterization, design, operation, and decommissioning processes of future low-level radioactive-waste disposal sites. Unconsolidated deposits at the site are diverse in lithologic character and are spatially and stratigraphically complex. Thickness of these Quaternary deposits ranges from 3 to 27 meters and averages 17 meters. The unconsolidated deposits overlay 140 meters of Pennsylvanian shale, mudstone, siltstone, and coal. Approximately 90,500 cubic meters of waste were buried from August 1967 through August 1978, in 21 trenches that were constructed in glacial materials by using a cut-and-fill process. Trenches generally were constructed below grade and ranged from 11 to 180 meters long, 2.4 to 21 meters wide, and 2.4 to about 7.9 meters deep. Research on microclimate and evapotranspiration at the site was conducted from July 1982 through June 1984. Continuous measurements were made of precipitation, incoming and reflected solar (shortwave) radiation, incoming and emitted terrestrial (longwave) radiation, horizontal windspeed and direction, wet- and dry-bulb air temperature, barometric pressure, soil-heat fluxes, and soil temperature. Soil-moisture content, for this research phase, was measured approximately biweekly. Evapotranspiration rates were estimated by using three techniques--energy budget, aerodynamic profile, and water budget. Although monthly totals for each method differed, estimated annual evapotranspiration averages ranged from 630 to 693 millimeters or about 70 percent of precipitation. Tritium concentrations in leaf water from on-site plants were determined for 125 vegetation samples collected during the summers of 1982 through 1986. Concentrations varied significantly among some locations and plant types. Tritium concentrations ranged from the detection limit of 0 .2 to 1,330 nanocuries per liter, with alfalfa (Medicago sativa) having the highest concentrations, followed by brome grass (Bromus inermis), and then red clover (Trifoleum pratense); these variations in concentration are most likely a result of root depth. Runoff and sediment transport were measured from July 1982 through December 1985 in four basins--three comprising almost two-thirds of the 8.1-hectare site and one comprising a 1.4-hectare undisturbed area. Volumes and equivalent weights of collapses were estimated from records of site surficial conditions from October 1978 through December 1985. Runoff showed a direct relation to degree of land modification; lowest mean yields were measured at the undisturbed area, and highest mean yields were measured from the basin composed wholly of trench and intertrench areas. Sediment yield measured onsite averaged 3.4 megagrams per hectare. A total of 315 collapse cavities, corresponding to a cumulative volume of about 500 cubic meters, were documented. Most collapses were recorded after periods of rainfall or snowmelt when soil moisture was near maximum. Almost two-thirds of the collapses, corresponding to 63 percent of the cumulative cavity volume, occurred during February through April. Data for the study of water movement through a trench cover were collected from July 1982 through June 1934. Pressure-head data were collected at four different clusters at depths ranging from 50 to 1,850 millimeters within a selected trench cover. Soil-moisture content for this research phase was measured weekly with a gamma-attenuation moisture probe. The amount of water stored within the trench cover fluctuated in an annual cycle. Moisture contents were greatest in late March or early April, decreased steadily from late spring through the summer, reached a minimum in late August or early September, and then increased gradually from midfall through the winter. Depths of wetting-front movements were a function of initial soil-moisture content and total storm precipitation. Seepage to the trench was estimated by use of four different methods: the Darcy method, the zero-flux phase method, the surface-based water-budget method, and the ground-water based water-budget method. Estimates by the different methods differed considerably. Investigation of the unsaturated zone at the site began in 1981 and is ongoing (1987). Water movement was measured along a generalized vertical section through four trenches. A 120-meter-long, 2-meter-diameter horizontal tunnel provided access below the trenches. The timing of water movement varied temporally and spatially. Vertical flow was inhibited at interfaces between lithologic units of contrasting hydraulic conductivities. Data also indicate that water movement through the sand of the Toulon Member of the Glasford Formation occurs along localized partially saturated to saturated flow paths. Average velocities of water movement through the extent of the unsaturated zone, as estimated by a saturation-tracking method, ranged from 0.04 to 0.34 meter per day. Tritium concentrations in the unsaturated zone varied spatially reflecting the heterogeneity of wastes in the overlying trenches and local hydrogeologic conditions. Tritium concentrations at all lysimeter locations increased with time; however, the increases usually were of small magnitude. Tritium concentrations increased abruptly, from five to nine times previous concentrations, at only 3 of 14 locations. Gas samples were collected from a network of soil-gas piezometers located in the undisturbed unsaturated zone near a waste trench at approximately 70-day intervals during 1984-86. Relative proportions of nitrogen, oxygen plus argon, carbon dioxide, methane, ethane, propane, butane, tritiated water vapor, carbon dioxide, and 222radon were converted to partial pressures, based on a mean atmospheric pressure of 98.6 kilopascals. Methane and 14 carbon dioxide were identified as originating in the waste and having mean partial pressures that generally decreased with horizontal distance from the trench and with vertical distance to the land surface. Partial-pressure gradients for other radioactive gases were not detected in the gas sampling network; definable gradients may occur much nearer to the waste source. Ground-water flow has been studied at the site since 1976. The spatial, stratigraphic, and lithologic complexity of the unconsolidated deposits that compose the shallow aquifer result in the free water surface intersecting nine different lithologic units at the site. Saturated hydraulic conductivities of these units range from about 4x10-12 to 8x10-6 centimeters per second. Three ground-water basins were defined within the shallow aquifer, with flow generally from west to east. Ground-water velocities are highly variable. A tracer test conducted in a pebbly-sand unit resulted in velocities in the range of 640 to 770 meters per year. Estimated velocities for the other units ranged from 2 to 490 meters per year. Tritium was detected in observation wells on-site in 1976 and off-site in 1982. Concentrations ranged from the analytical detection limit of 0.2 to over 300 nanocuries per liter. Seasonal variations in tritium concentrations were observed in most wells, and dilution caused by infiltrating rainfall was observed. Water-chemistry research included the collection and analysis of precipitation, geologic materials, and unsaturated- and saturated-zone water, both on-site and off-site, and in all geologic units, during 1978 to 1984. Precipitation was a calcium-zinc-sulfate type water. Calcium and bicarbonate were the most abundant cation and anion, respectively, in the geologic materials. Mean dissolved organic carbon and tritium concentrations (45 milligrams per liter and 290 nanocuries per liter, respectively) were greater in samples from six lysimeters located directly below waste trenches and one located within a trench, than in samples from all other lysimeters (8.4 milligrams per liter and 17 nanocuries per liter, respectively). Water in the saturated zone was generally a magnesium-bicarbonate type. Tritium was the only radionuclide detected in the saturated zone.

Illinois↗