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This project is focused on developing objective methods for evaluating USGS hydrologic-data-collection activities; such methods are needed so that activities can be modified when necessary and the efficiency of USGS operations maximized.
Categories: Project; Tags: Statistical Hydrology
1) Improve predictions of streamflow at ungaged basins, and 2) understanding the causes of streamflow changes due to human changes to the environment, and 3) establish biological-flow relations.
Using long-term data records, this project is focused on two problems of importance to water resources managers. First, long-term streamflow records are being used to a) identify broad regional to national trends in floods and low-flows and relate them to possible causes (climate change, water management changes, land-cover changes, and ground-water level change) and b) determine whether there are patterns that relate to watershed size or climate characteristics. It is often stated in the popular press and in official publications on global climate change that we can expect increased variability, including larger and/or more frequent floods, and deeper and longer droughts, as a result of greenhouse warming. This...
The NRP had its beginnings in the late 1950's. Since that time, the program has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, ecology, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation's water resources. Results of NRP's long-term research investigations often lead to the development of new concepts, techniques, and approaches that are applicable not only to the solution of current water problems, but also to future issues that may affect the Nation's water resources. Basic tools of hydrology that have been developed by the...
Categories: Project; Types: ScienceBase Project; Tags: Acid Mine Drainage, Aquatic Habitat, Arid Land Hydrology, Carbon Cycle, Contaminant Reactions and Transport, All tags...
Uncertainty in application of physically based surface-water hydrologic models is a function of adequacy of the conceptualization of the processes involved and of the quantity and quality of data available to use as input to the model. In any type of modeling exercise, even if the physical processes are well understood, spatial heterogeneities make application of the model on a basin-wide scale problematic, and it is almost always necessary to use some form of spatial averaging to obtain 'effective' input variables. The over-all goal of our research is to investigate: (1) Model output errors as a function of model complexity and uncertainty in model input, (2) Derivation of simplified yet physically based models...
There are a variety of ground-water resource and contamination problems that involve determining the state of ground water and detecting or predicting changes in the ground-water environment. Most approaches to ground-water monitoring network design avoid a rigorous formulation of the monitoring objectives and fail to consider the important processes controlling the movement of ground water and migration of ground-water contaminants. It is unlikely that such approaches to network design will be able to effectively and efficiently monitor the subsurface environment in the face of limited resources. This research aims to develop statistically sound and simulation based methods for ground-water monitoring network design....
Managing water use in riverine and estuarine systems requires an understanding of the governing supply, circulation, mixing, and flushing processes. Qualitative and quantitative evaluation of the hydrodynamic and transport properties of such water bodies can be computed via mathematical/numerical simulation models. To accurately simulate both the temporal and spatial variations of the flow, which significantly define the transport processes, the simulation model must be capable of accounting for hydraulic and tide-induced fluctuations, water withdrawals, discharges, winds, nonuniform geometric configurations, and other manmade or natural factors. Objectives of this project are to investigate and develop various...
The Lake-Atmosphere Interactions project (LAIP) develops and applies regional and global climate models and surface process models in the context of broadly interdisciplinary research aimed at addressing past, present and future climate hypotheses, questions and issues and at providing climate data for applied research. The project research is conducted across a wide range of temporal (the past 106 years and into the future) and spatial (global to local) scales. Project objectives are achieved by developing and applying a variety of numerical models, visualization techniques, web-based applications and statistical methods to quantify and explain interactions between the atmosphere, lakes, aquatic and terrestrial...
Advance the utility of environmental models by improving how models are tested against data and how they are used to understand simulated processes, predictions and prediction uncertainty. This includes ways of making models more transparent and refutable. Making a model transparent means that tests of model adequacy are clearly defined and conducted and the importance of different aspects of the model to predictions of interest are readily apparent. Thus, in more transparent models it is easier to determine what data and simulated processes dominate model development, predictions, and measures of prediction uncertainty. I consider sensitivity analysis to be a primary way of making models more transparent. Making...
My research can be broadly characterized as the use of statistics to simplify, understand and address complex, cross-disciplinary water resource problems. I have a particular interest in using statistics to arrive at parsimonious characterizations of natural systems and I am employing this philosophy to advance understanding in the areas of ecohydrology, sustainable water management at unmonitored locations, and trends in long-term environmental time series. By pioneering original insights into the statistical properties of streamflow time series, I am opening new pathways to determine surface-water availability at unmonitored locations and to classify streamgauges into ecologically-relevant management groups. My...
The regional nature of hydrologic processes is generally defined in terms of shared meteorological and basin characteristics. Inferences have been attempted by regressing the parameters of hydrologic interest against these characteristics. Such analyses have not been able to fully explain the variations, extremes or persistence of discharge patterns observed within a geographic area. An accounting of anthropogenic effects on basin characteristics needs to be made. Longer term influences such as decadal to centennial, and millennial climatic fluctuations need to be considered, and the stochastic structure of the hydrologic process itself needs to be studied. The objectives of this project are (1.) to develop secular...
Many aspects of ground-water flow and transport resist standard, deterministic modeling techniques: either there exist elements which are overly complex or which are simply unpredictable. These elements may have either a spatial character, as heterogeneity in porous media, or a temporal character, as recharge events to an aquifer. Provided that an adequate representation can be found, then these aspects of flow and transport frequently are better modeled by taking the complex or unpredictable element to be a stochastic process. Given an adequate representation, then the following questions may be addressed: (1) What is the implication of these elements for flow and transport in porous media? (2) Given observations...
Categories: Project; Tags: Statistical Hydrology