Scale issues in soil moisture modelling: problems and prospects

Soil moisture storage is an important component of the hydrological cycle and plays a key role in land-surface-atmosphere interaction. The soil-moisture storage equation in this study considers precipitation as an input and soil moisture as a residual term for runoff and evapotranspiration. A number of models have been developed to estimate soil moisture storage and the components of the soil-moisture storage equation. A detailed discussion of the impli cation of the scale of application of these models reports that it is not possible to extrapolate processes and their estimates from the small to the large scale. It is also noted that physically based models for small-scale applications are sufficiently detailed to reproduce land-surface- atmosphere interactions. On the other hand, models for large-scale applications oversimplify the processes. Recently developed physically based models for large-scale applications can only be applied to limited uses because of data restrictions and the problems associated with land surface characterization. It is reported that remote sensing can play an important role in over coming the problems related to the unavailability of data and the land surface characterization of large-scale applications of these physically based models when estimating soil moisture storage.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Annual report of the Environmental Restoration Monitoring and Assessment Program at Oak Ridge National Laboratory for FY 1992

This report summarizes the salient features of the annual efforts of the investigations and monitoring, conducted to support the Environmental Restoration (ER) Program at Oak Ridge National Laboratory (ORNL). The results presented can be used to develop a conceptual understanding of the key contaminants and the sources, fluxes, and processes affecting their distribution and movement. This information forms a basis for prioritizing sites and for selecting, implementing, and evaluating remedial actions. Groundwater, soils, sediments, and surface water monitoring results are described

Oak Ridge greater confinement disposal demonstrations

Demonstrations are being conducted in association with the disposal of a high activity low-level waste (LLW) stream. The waste stream in question will result from the cement solidification of decanted liquids from the Melton Valley Storage Tanks (MVST). The solid waste will be produced beginning in mid summer 1988. It is anticipated to have significant concentrations of Cs-137 and Sr-90, with smaller amounts of other radionuclides and <100 nCi/gm of TRU. The solid waste forms are expected to have surface dose rates in the 1 to 2 r/hr range. The solid waste will also contain several chemical species at concentrations which are below those of concern, but which may present enhanced corrosion potential for the disposal units. 2 refs., 5 figs

Tumulus Disposal Demonstration Facility for the Oak Ridge Reservation

This disposal concept is based on the Tumulus design developed by the French at the La Manche facility. Waste units are stacked above-grade on a concrete pad. The facility currently under development at the Oak Ridge National Laboratory (ORNL) involves sealing waste in concrete vaults, placing the vaults on a grade level concrete pad, and covering the pad and vaults with a soil cover after vault emplacement is complete. Emplacement is expected to continue until the facility exhausts its approximate 800 m/sup 3/ (28,000 ft/sup 3/) capacity. The facility incorporates engineered barriers to radionuclide migration; a monitoring system to ensure barrier performance; and a newly developed set of Demonstration Waste Acceptance Criteria to reduce the likelihood of groundwater contamination

Simulation of contaminated sediment transport in White Oak Creek basin

This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ({sup 137}Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of {sup 137}Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies

Annual hydrologic data summary for the White Oak Creek Watershed: Water Year 1990 (October 1989--September 1990)

This report summarizes, for the Water Year 1990 (October 1989-- September 1990), the dynamic hydrologic data collected on the Whiteoak Creek (WOC) Watershed's surface and subsurface flow systems. These systems affect the quality or quantity of surface water and groundwater. The collection of hydrologic data is one component of numerous, ongoing Oak Ridge National Laboratory (ORNL) environmental studies and monitoring programs and is intended to 1. characterize the quantity and quality of water in the flow system, 2. plan and assess remedial action activities, and 3. provide long-term availability of data and assure quality. Characterizing the hydrology of the WOC watershed provides a better understanding of the processes which drive contaminant transport in the watershed. Identifying of spatial and temporal trends in hydrologic parameters and mechanisms that affect the movement of contaminants supports the development of interim corrective measures and remedial restoration alternatives. Hydrologic monitoring supports long-term assessment of the effectiveness of remedial actions in limiting the transport of contaminants across Waste Area Grouping boundaries and ultimately to the off-site environment. The majority of the data summarized in this report are available from the Remedial Action Programs Data and Information Management System data base. Surface water data available within the WOC flow system include discharge and runoff, surface water quality, radiological and chemical contamination of sediments, and descriptions of the outfalls to the WOC flow system. Climatological data available for the Oak Ridge area include precipitation, temperature, humidity, wind speed, and wind direction. Information on groundwater levels, aquifer characteristics, and groundwater quality are presented. Anomalies in the data and problems with monitoring and accuracy are discussed. 58 refs., 54 figs., 15 tabs

Use of electromagnetic borehole flowmeter to delineate groundwater producing fractures

Ground water flow on the Oak Ridge Reservation (ORR) is dominated by permeable fractures within the relatively impermeable rocks. It is possible to detect the fractures which intersect a borehole using conventional logging tools (electrical, sonic, acoustic televiewer, caliper, temperature), but not with any certainty which of these fractures are permeable and are part of a connected network. This poses a problem for the groundwater modeler. Should all known fractures be included in the model Only major fracture