USGS initiated the Water, Energy, and Biogeochemical Budgets (WEBB) program to understand the processes controlling water, energy, and biogeochemical fluxes over a range of temporal and spatial scales, and the effects of atmospheric and climatic variables. Trout Lake is one of five small, geographically and ecologically diverse watersheds representing a range of hydrologic and climatic conditions.
SITE DESCRIPTION
The Trout Lake WEBB site is in the Northern Highland area of north-central Wisconsin. The site includes five open lakes and two bog lakes. It is also the site of the NSF-sponsored North Temperate Lakes Long-Term Ecological Research (NTL/LTER) project, which has been ongoing since 1980 under the direction of the Center for Limnology, University of Wisconsin-Madison. The WEBB hydrologic and biogeochemical research in the LTER lake watersheds complements the ecological research conducted at the NTL/LTER, which is focused on in-lake processes. In this sparsely populated area, many lakes have totally forested watersheds and no private frontage.
Geologic features of the area are dominated by a sandy outwash plain consisting of 30 to 50 meters of unconsolidated sand and coarser till overlying Precambrian igneous bedrock. The predominant soils are thin forest soils with high organic content in the uppermost horizon. The site is representative of the glacial lake districts common to the upper Midwest and Canada, but certain individual characteristics distinguish it from other nearby lake areas. Among the most important of these characteristics is glacial drift that is virtually carbonate free; as a result, the ground-water chemistry is almost entirely controlled by silicate hydrolysis.
Most of the lakes in the Northern Highland area are seepage lakes--they have no surface-water inlets or outlets. Water budgets are thus dominated by direct precipitation, ground-water flow, and evapotranspiration. The seven study lakes, four of which are seepage lakes, are all in the same ground-water-flow system. Lakes in topographic highs, such as the two bog lakes and Crystal Lake, receive little ground-water flow and no streamflow and have water with low ionic concentrations (10 to 20 microSiemens per centimeter, mS/cm). Lakes in topographic lows, such as Trout Lake, are dominated by ground-water and stream inputs and have water with higher ionic concentrations (70 to 90 mS/cm). Although linked by a common ground-water-flow system and similar climate, the lakes represent a broad range of size, morphometry, habitat, thermal features, chemistry, biological productivity, and species composition.
RESEARCH AREAS
Rainfall, Streamflow, and Recharge Processes
Objectives:
- Investigate the processes controlling streamflow generation in response to rainfall for low-relief hydrologic settings.
- Investigate the processes that lead to ground-water recharge in the TL basin.
- Develop appropriate predictive capabilities for the identified streamflow-generation and ground-water-recharge processes.
- Investigate the implications of increases in spatial and temporal scale on the predictive capabilities.
Approach:
- Use stable isotopes of water (oxygen-18 and deuterium) to identify streamflow-generation mechanisms by examining the isotopic evolution of water as in moves through the hydrologic system. Three detailed hillslope sites along Allequash Creek are instrumented with nested piezometers, lysimeters and bulk rainfall and throughfall collectors.
Groundwater/Surface Water Interactions
Objectives:
- Determine the water and solute yields for the Trout Lake Basin and determine the relative importance of streamflow to the water and solute budgets for Trout Lake.
- Identify the geochemical processes that control the flux of major chemical species (such as nitrogen and sulfur species) at the aquifer-lake and aquifer-stream interfaces, and the temporal and spatial variability of these processes.
Approach:
- Streams tributary to Trout Lake are sampled periodically to allow the computation of solute fluxes from streams into and out of Trout Lake. The samples are analyzed for nutrients and major ions. The importance of surface-water sources to the complete hydrologic and chemical budget of Trout Lake is being determined from the estimated surface-water fluxes and the existing NTL/LTER data base.
- Processes that control the mass flux of chemical species across the stream interface are being identified by means of fine-scale sampling (that is, less than 1 centimeter, cm). The samples are collected at various times of the year at two locations along Allequash Creek. Samples are also collected periodically from a detailed transect along Allequash Creek to determine larger-scale variations.
Carbon Flux Processes
Objectives:
- Identify the processes that control the flux of major carbon species (such as dissolved inorganic carbon, dissolved organic carbon, carbon dioxide and methane) within the Allequash Creek watershed, and the temporal and spatial variability of these processes.
Approach:
- Carbon fluxes are being estimated through periodoc sampling of various system components (see carbon flux schematic for details), and measured directly for soil effux using soil chambers. A variety of land cover and slope/aspect combinations are being sampled to help pinpoint the spatial variability.
Below are publications associated with this project.
Estimating groundwater exchange with lakes: 1. The stable isotope mass balance method
Estimating groundwater exchange with lakes: 2. Calibration of a three-dimensional, solute transport model to a stable isotope plume
Simulating the effect of climate change on stream temperature in the Trout Lake Watershed, Wisconsin
MODFLOW-style parameters in underdetermined parameter estimation
Characterizing climate-change impacts on the 1.5-yr flood flow in selected basins across the United States: a probabilistic approach
Integrated watershed-scale response to climate change for selected basins across the United States
Approaches to highly parameterized inversion: A guide to using PEST for model-parameter and predictive-uncertainty analysis
Approaches to highly parameterized inversion: Pilot-point theory, guidelines, and research directions
Using a cloud to replenish parched groundwater modeling efforts
Approaches to highly parameterized inversion-A guide to using PEST for groundwater-model calibration
Importance of unsaturated zone flow for simulating recharge in a humid climate
Using high hydraulic conductivity nodes to simulate seepage lakes
Below are news stories associated with this project.
Below are partners associated with this project.
- Overview
USGS initiated the Water, Energy, and Biogeochemical Budgets (WEBB) program to understand the processes controlling water, energy, and biogeochemical fluxes over a range of temporal and spatial scales, and the effects of atmospheric and climatic variables. Trout Lake is one of five small, geographically and ecologically diverse watersheds representing a range of hydrologic and climatic conditions.
SITE DESCRIPTION
The Trout Lake WEBB site is in the Northern Highland area of north-central Wisconsin. The site includes five open lakes and two bog lakes. It is also the site of the NSF-sponsored North Temperate Lakes Long-Term Ecological Research (NTL/LTER) project, which has been ongoing since 1980 under the direction of the Center for Limnology, University of Wisconsin-Madison. The WEBB hydrologic and biogeochemical research in the LTER lake watersheds complements the ecological research conducted at the NTL/LTER, which is focused on in-lake processes. In this sparsely populated area, many lakes have totally forested watersheds and no private frontage.
Geologic features of the area are dominated by a sandy outwash plain consisting of 30 to 50 meters of unconsolidated sand and coarser till overlying Precambrian igneous bedrock. The predominant soils are thin forest soils with high organic content in the uppermost horizon. The site is representative of the glacial lake districts common to the upper Midwest and Canada, but certain individual characteristics distinguish it from other nearby lake areas. Among the most important of these characteristics is glacial drift that is virtually carbonate free; as a result, the ground-water chemistry is almost entirely controlled by silicate hydrolysis.
Most of the lakes in the Northern Highland area are seepage lakes--they have no surface-water inlets or outlets. Water budgets are thus dominated by direct precipitation, ground-water flow, and evapotranspiration. The seven study lakes, four of which are seepage lakes, are all in the same ground-water-flow system. Lakes in topographic highs, such as the two bog lakes and Crystal Lake, receive little ground-water flow and no streamflow and have water with low ionic concentrations (10 to 20 microSiemens per centimeter, mS/cm). Lakes in topographic lows, such as Trout Lake, are dominated by ground-water and stream inputs and have water with higher ionic concentrations (70 to 90 mS/cm). Although linked by a common ground-water-flow system and similar climate, the lakes represent a broad range of size, morphometry, habitat, thermal features, chemistry, biological productivity, and species composition.
RESEARCH AREAS
Middle Allequash stream site in winter, 2003 Rainfall, Streamflow, and Recharge Processes
Objectives:
- Investigate the processes controlling streamflow generation in response to rainfall for low-relief hydrologic settings.
- Investigate the processes that lead to ground-water recharge in the TL basin.
- Develop appropriate predictive capabilities for the identified streamflow-generation and ground-water-recharge processes.
- Investigate the implications of increases in spatial and temporal scale on the predictive capabilities.
Approach:
- Use stable isotopes of water (oxygen-18 and deuterium) to identify streamflow-generation mechanisms by examining the isotopic evolution of water as in moves through the hydrologic system. Three detailed hillslope sites along Allequash Creek are instrumented with nested piezometers, lysimeters and bulk rainfall and throughfall collectors.
Groundwater/Surface Water Interactions
Objectives:
- Determine the water and solute yields for the Trout Lake Basin and determine the relative importance of streamflow to the water and solute budgets for Trout Lake.
- Identify the geochemical processes that control the flux of major chemical species (such as nitrogen and sulfur species) at the aquifer-lake and aquifer-stream interfaces, and the temporal and spatial variability of these processes.
Approach:
- Streams tributary to Trout Lake are sampled periodically to allow the computation of solute fluxes from streams into and out of Trout Lake. The samples are analyzed for nutrients and major ions. The importance of surface-water sources to the complete hydrologic and chemical budget of Trout Lake is being determined from the estimated surface-water fluxes and the existing NTL/LTER data base.
- Processes that control the mass flux of chemical species across the stream interface are being identified by means of fine-scale sampling (that is, less than 1 centimeter, cm). The samples are collected at various times of the year at two locations along Allequash Creek. Samples are also collected periodically from a detailed transect along Allequash Creek to determine larger-scale variations.
Carbon Flux Processes
Objectives:
- Identify the processes that control the flux of major carbon species (such as dissolved inorganic carbon, dissolved organic carbon, carbon dioxide and methane) within the Allequash Creek watershed, and the temporal and spatial variability of these processes.
Approach:
- Carbon fluxes are being estimated through periodoc sampling of various system components (see carbon flux schematic for details), and measured directly for soil effux using soil chambers. A variety of land cover and slope/aspect combinations are being sampled to help pinpoint the spatial variability.
- Publications
Below are publications associated with this project.
Filter Total Items: 32Estimating groundwater exchange with lakes: 1. The stable isotope mass balance method
Groundwater inflow and outflow contributions to the hydrologic budget of lakes can be determined using a stable isotope (18O/16O) mass balance method. The stable isotope method provides a way of integrating the spatial and temporal complexities of the flow field around a lake, thereby offering an appealing alternative to the traditional time and labor intensive methods using seepage meters and anEstimating groundwater exchange with lakes: 2. Calibration of a three-dimensional, solute transport model to a stable isotope plume
A three-dimensional groundwater flow and solute transport model was calibrated to a plume of water described by measurements of δ18O and used to calculate groundwater inflow and outflow rates at a lake in northern Wisconsin. The flow model was calibrated to observed hydraulic gradients and estimated recharge rates. Calibration of the solute transport submodel to the configuration of a stable isotoSimulating the effect of climate change on stream temperature in the Trout Lake Watershed, Wisconsin
The potential for increases in stream temperature across many spatial and temporal scales as a result of climate change can pose a difficult challenge for environmental managers, especially when addressing thermal requirements for sensitive aquatic species. This study evaluates simulated changes to the thermal regime of three northern Wisconsin streams in response to a projected changing climate uMODFLOW-style parameters in underdetermined parameter estimation
In this article, we discuss the use of MODFLOW-Style parameters in the numerical codes MODFLOW_2005 and MODFLOW_2005-Adjoint for the definition of variables in the Layer Property Flow package. Parameters are a useful tool to represent aquifer properties in both codes and are the only option available in the adjoint version. Moreover, for overdetermined parameter estimation problems, the parameterCharacterizing climate-change impacts on the 1.5-yr flood flow in selected basins across the United States: a probabilistic approach
The U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) model was applied to basins in 14 different hydroclimatic regions to determine the sensitivity and variability of the freshwater resources of the United States in the face of current climate-change projections. Rather than attempting to choose a most likely scenario from the results of the Intergovernmental Panel on Climate ChaIntegrated watershed-scale response to climate change for selected basins across the United States
A study by the U.S. Geological Survey (USGS) evaluated the hydrologic response to different projected carbon emission scenarios of the 21st century using a hydrologic simulation model. This study involved five major steps: (1) setup, calibrate and evaluated the Precipitation Runoff Modeling System (PRMS) model in 14 basins across the United States by local USGS personnel; (2) acquire selected simuApproaches to highly parameterized inversion: A guide to using PEST for model-parameter and predictive-uncertainty analysis
Analysis of the uncertainty associated with parameters used by a numerical model, and with predictions that depend on those parameters, is fundamental to the use of modeling in support of decisionmaking. Unfortunately, predictive uncertainty analysis with regard to models can be very computationally demanding, due in part to complex constraints on parameters that arise from expert knowledge of sysApproaches to highly parameterized inversion: Pilot-point theory, guidelines, and research directions
Pilot points have been used in geophysics and hydrogeology for at least 30 years as a means to bridge the gap between estimating a parameter value in every cell of a model and subdividing models into a small number of homogeneous zones. Pilot points serve as surrogate parameters at which values are estimated in the inverse-modeling process, and their values are interpolated onto the modeling domaiUsing a cloud to replenish parched groundwater modeling efforts
Groundwater models can be improved by introduction of additional parameter flexibility and simultaneous use of soft-knowledge. However, these sophisticated approaches have high computational requirements. Cloud computing provides unprecedented access to computing power via the Internet to facilitate the use of these techniques. A modeler can create, launch, and terminate “virtual” computers as neeApproaches to highly parameterized inversion-A guide to using PEST for groundwater-model calibration
Highly parameterized groundwater models can create calibration difficulties. Regularized inversion-the combined use of large numbers of parameters with mathematical approaches for stable parameter estimation-is becoming a common approach to address these difficulties and enhance the transfer of information contained in field measurements to parameters used to model that system. Though commonly useImportance of unsaturated zone flow for simulating recharge in a humid climate
Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing the same volume of water through an unsaturated zone column to the waterUsing high hydraulic conductivity nodes to simulate seepage lakes
In a typical ground water flow model, lakes are represented by specified head nodes requiring that lake levels be known a priori. To remove this limitation, previous researchers assigned high hydraulic conductivity (K) values to nodes that represent a lake, under the assumption that the simulated head at the nodes in the high-K zone accurately reflects lake level. The solution should also produce - News
Below are news stories associated with this project.
- Partners
Below are partners associated with this project.