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

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

The Accuracy of Owner-Provided House Values: The 1978-1991 American Housing Survey

The American Housing Survey (AHS) includes the owner's valuation of the house as a measure of the house's value. If owner-stated values are accurate, the AHS (as well as other survey instruments) can be used by researchers studying a variety of topics. In this study we use the metropolitan version of the AHS for three cities over fourteen years to compare owners' valuations with sales prices of houses that sold in the twelve months prior to an interview. We find that, on average, recent buyers report house values that are 8.4% higher than the stated sales prices. Further analysis indicates that these recent buyers, when compared with owners with longer tenure, overvalue their houses by 3.3%, on average. Thus, we find that the average owner overvalues his house by 5.1%. Also, differences between sales prices and owners' valuations are not related to particular characteristics of the house, occupants (other than length of tenure), or neighborhood. Thus, the use of the owners' valuations will result in accurate estimates of house price indexes and will provide reliable estimates of the prices of house and neighborhood characteristics. Copyright American Real Estate and Urban Economics Association.

Chicago's Office Market: Price Indices, Location and Time

Conventional wisdom holds that overbuilding and high vacancy, coupled with curtailed tax benefits, have led to reduced office property values since the late 1980s. Yet assertions that office real estate values fell between the mid-1980s and mid-1990s are not supported everywhere by convincing evidence. This study offers a hedonic analysis of Chicago area office properties that sold from 1986 through 1993. Whereas earlier office market studies generally have been based on rents, this study focuses on variation in actual sale prices (although the prices were not adjusted for financing differences). The transaction-based index estimated here does not support the existence of a nominal office property price level decline beginning in the mid-to-late 1980s. In fact, the results show an upward trend in office property values after 1986, with nominal declines in office market price levels occurring only in the latter portion of the study period. Copyright American Real Estate and Urban Economics Association.