Evaluating the effectiveness of air quality management within the class I area of great smoky mountains national park

The Clean Air Act Amendments of 1977 designated national parks and wilderness areas larger than 1894 ha to be class I areas for air quality management, setting more restrictive criteria than the National Ambient Air Quality Standards. Class I areas are afforded the greatest degree of air quality protection under the Clear Air Act of 1970. In recent years, several studies have documented air pollution effects in the Great Smoky Mountains National Park (GSMNP), the second-largest class I area in the eastern United States. Air pollution problems of greatest concern in the GSMNP are effects of acid deposition, visibility impairment, and tropospheric ozone. Several recent events have increased concerns about air quality management in the class I area of the GSMNP. A forum, sponsored by the Southern Appalachian Man and the Biosphere Cooperative (SAMAB), was held in March 1992, which involved representative. parties-at-interest and began to address strategies for better management of air resources in the Southern Appalachians. This paper summarizes those discussions and recommendations and reports actions occurring as a result of the forum. Another objective of this paper is to present a conceptual framework for more effective management of the class I area of the GSMNP.     

DESIGN BASIS FOR EVERGLADES STORMWATER TREATMENT AREAS1

ABSTRACT: The State of Florida (1994) has adopted a plan for addressing Everglades eutrophication problems by reducing anthropogenic phosphorus loads. The plan involves implementation of Best Management Practices in agricultural watersheds and construction of regional treatment marshes (Stormwater Treatment Areas or STA's). This paper describes the development, testing, and application of a mass-balance model for sizing STA's to achieve treatment objectives. The model is calibrated and tested against peat and water-column data collected in Water Conservation Area-2A (WCA-2A), where phosphorus dynamics and eutrophication impacts have been intensively studied. The 26-year-average rate of phosphorus accretion in peat is shown to be proportional to average water-column phosphorus concentration, with a proportionality constant of 10.2 m/yr (90 percent Confidence Interval = 8.9 to 11.6 m/yr). Spatial and temporal variations in marsh water-column data suggest that drought-induced recycling of phosphorus was important during periods of low stage in WCA-2A. Maintaining wet conditions will be important to promote phosphorus removal in STA's. Sensitivity analysis of STA performance is conducted over the range of uncertainty in model parameter estimates to assess the adequacy of the model as a basis for STA design.     

NUMERICAL MODELING OF SALTWATER INTRUSION IN THE NORTHERN GUAM LENS1

ABSTRACT This paper deals with the application of a two-dimensional, saltwater intrusion model to the aquifer in Northern Guam. The model used finite element theory and the Galerkin, weighted-residual technique as its basis. The Northern Guam lens was discretized into 299 linear, triangular elements and 189 nodes. The model was calibrated using 1978 hydrologic data. The output of the model was compared with measured water levels in six observation wells. The calibrated values of permeability and porosity were then used to verify the model using 1979 data. A calibrated and verified model can be used to make an infinite variety of management and planning studies. In this study, three applications are provided that would be considered typical management runs. Steady state runs were made to compare the four conditions of no pumping, 1978 pumping levels, twice 1978 pumping levels, and five times 1978 pumping levels. The water levels due to these conditions are shown in plan and in cross sections of the aquifer. The effect of zero recharge to the aquifer is next demonstrated for the pumping levels existing during 1978. The final run shows how long the aquifer takes to reach steady state when the pumping rate is increased from the 1978 pumping level to twice that value. The program can be used for numerous other studies for management and planning purposes.     

VELOCITY EQUATION FOR WATER QUALITY MODELING IN GEORGIA1

ABSTRACT: Tabletop water quality modeling still plays an important role in the water pollution control activities of the Georgia Environmental Protection Division. Tabletop models are those developed with out the aid of extensive field data. One important component of GEORGIA DOSAG, our basic water quality model, is the equation used to predict flow through velocity. However, Georgia is characterized by wide physiographic diversity which reduces the effectiveness of uncalibrated velocity equations. Using 15 years of accumulated time-of-travel studies, a series of empirical velocity equations were developed and calibrated to various physiographic conditions in Georgia. Equations are available for each major soil province and for three stream flow ranges within each province - Q<100 cfs, 100<Q<1000 cfs, and Q>1000 cfs. Now, in the absence of extensive field data, we have data based velocity equations which can be tailored to each site under study.     

A dynamic model for intertemporal allocation of old-growth forests in the Pacific Northwest

Across the globe, continued policy debates regarding the management of old-growth forests center around the difficult task of balancing economic and ecological considerations. Though the forests of the Pacific Northwest United States are among the most studied old-growth ecosystems, ecological and economic analyses have yielded public land management directives that remain controversial. Specifically, the recently adopted Northwest Forest Plan lacks explicit goals for maintaining intergenerational equity for the use of forest resources and the diversity of old-growth ecosystems. Unlike previous studies which rely on monetary quantification of costs and benefits, this study develops and applies a conceptual framework for evaluating socially optimal Pacific Northwest old-growth forest utilization strategies. Conditions for the optimal management of old-growth forests are derived using dynamic programming. The objective function synthesizes relevant biological and economic attributes of the old-growth allocation problem. Results in the form of extraction paths are compared given social pressure for consumptive and non-consumptive benefits, as well as different planning horizons, rates of social time preference, and environmental variance. Lengthening the planning horizon results in a vast divergence of optimal policies in the absence of discounting. Extraction rates appear to approach zero as the planning horizon approaches infinity. While higher rates of social time preference increase the rate of extraction, forest stocks remaining at the terminal time period equal levels remaining with a lower discount rate. Increasing environmental variance results in a higher level of stock remaining at the terminal time period. This analysis, while specific to the old-growth controversy of the Pacific Northwest, does provide general guidelines for addressing similar problems of multiple uses of natural areas, particularly where such uses are mutually incompatible, or where one use may be irreversibly destructive to another.     

ARCGIS‐SWAT: A GEODATA MODEL AND GIS INTERFACE FOR SWAT1

This paper presents ArcGIS‐SWAT, a geodata model and geographic information system (GIS) interface for the Soil and Water Assessment Tool (SWAT). The ArcGIS‐SWAT data model is a system of geodatabases that store SWAT geographic, numeric, and text input data and results in an organized fashion. Thus, it is proposed that a single and comprehensive geodatabase be used as the repository of a SWAT simulation. The ArcGIS‐SWAT interface uses programming objects that conform to the Component Object Model (COM) design standard, which facilitate the use of functionality of other Windows‐based applications within ArcGIS‐SWAT. In particular, the use of MS Excel and MATLAB functionality for data analysis and visualization of results is demonstrated. Likewise, it is proposed to conduct hydrologic model integration through the sharing of information with a not‐model‐specific hub data model where information common to different models can be stored and from which it can be retrieved. As an example, it is demonstrated how the Hydrologic Modeling System (HMS) ‐ a computer application for flood analysis ‐ can use information originally developed by ArcGIS‐SWAT for SWAT. The application of ArcGIS‐SWAT to the Seco Creek watershed in Texas is presented.     

AN INTEGRATED ONE‐DIMENSIONAL AND TWO‐DIMENSIONAL URBAN STORMWATER FLOOD SIMULATION MODEL1

ABSTRACT: Flash flooding is the rapid flooding of low lying areas caused by the stormwater of intense rainfall associated with thunderstorms. Flash flooding occurs in many urban areas with relatively flat terrain and can result in severe property damage as well as the loss of lives. In this paper, an integrated one‐dimensional (1‐D) and two‐dimensional (2‐D) hydraulic simulation model has been established to simulate stormwater flooding processes in urban areas. With rainfall input, the model simulates 2‐D overland flow and 1‐D flow in underground stormwater pipes and drainage channels. Drainage channels are treated as special flow paths and arranged along one or more sides of a 2‐D computational grid. By using irregular computation grids, the model simulates unsteady flooding and drying processes over urban areas with complex drainage systems. The model results can provide spatial flood risk information (e.g., water depth, inundation time and flow velocity during flooding). The model was applied to the City of Beaumont, Texas, and validated with the recorded rainfall and runoff data from Tropical Storm Allison with good agreement.     

INVESTIGATION OF TURBIDITY MAXIMUM IN A MESOTIDAL ESTUARY,TAIWAN1

ABSTRACT: To comprehend the distributions of salinity, temperature, and suspended sediment in the Danshuei River estuary in Taiwan, monthly field surveys were conducted in 2003. These included several high and low slackwater surveys and intensive surveys. The results show that the Danshuei River estuary is predominately a partially mixed estuary. The highest concentration of suspended sediment is typically observed at the Chung‐Hsin Bridge, the most upstream sampling station. The suspended sediment concentration exhibits a general decreasing trend in the downstream direction. It may be concluded that the sediments mostly come from the upstream reach. A locally high concentration of suspended sediment is found at the Kuan‐Du station because of the local deep channel bathymetry and two‐layered estuarine circulation. A vertical two‐dimensional hydrodynamic and sediment transport model is applied to investigate the tidally averaged salinity distribution, residual circulation, and suspended sediment concentration. The modeling results reveal that, under the Q₇₅ flow condition (i.e., low flow), a turbidity maximum occurs at the Kuan‐Du station due to the strong estuarine circulation. The model simulation with a much higher river flow condition results in a weaker residual circulation and weaker turbidity maximum.     

WEST AFRICA: VOLTA DISCHARGE DATA QUALITY ASSESSMENT AND USE1

ABSTRACT: Water resource management in West Africa is often a complicated process due to inadequate resources, climatic extremes, and insufficient hydrological information. Insufficient data hinder sustainable watershed management practices, one of the top priorities in the Volta River Basin. This research properly fills in missing data by modeling the hydrological distribution in the Volta River Basin. On average, discharge gages across the basin are missing 20 percent of their monthly data over 20 years. Two methods were used to supplement missing data: a statistically linear model and a conceptual hydrological model. A linear equation, developed from the regression of precipitation and runoff, was used to evaluate the quality of existing data. The hydrological model separates the system into root and groundwater zones. Measured values were used to calibrate the hydrological model and to validate the statistical model. The quality of existing data was analyzed and organized for usability. Accuracy of the hydrological model was also evaluated for its effectiveness using R² and standard error. It was found that the hydrological model was an improvement from the linear model on a monthly basis; R² values improved by as much as 0.5 and monthly error decreased. Monthly predictions of the hydrological model were used to fill gaps of measured data sets.