Modeling hydrology and eutrophication in a Louisiana swamp forest ecosystem

The EPA Storm Water Management Model (1971) was used to model hydrodynamics, nutrient dynamics, and eutrophication in a Louisiana swamp forest ecosystem. The present system of canals and spoil banks in the swamp causes impoundment of swamp areas and does not optimize discharge from the swamp forest. Simulations showed that hydraulics could be managed to increase discharge rates to the lower estuary (22 percent), to increase productivity of the swamp forest (100 percent), and to decrease lake eutrophication (43 percent). This could be done by removing spoil banks in the swamp and allowing upland runoff to pass through the backswamp.     

INERTIA AND RECOVERY: AN APPROACH TO STREAM CLASSIFICATION AND STRESS EVALUATION1

ABSTRACT: The concepts of inertia and elasticity were applied to existing fish data from Conowingo Creek. It was determined that these two concepts could form the foundation for a stream classification system based on the structure and function of fish communities. Inertia appears to be more useful for predicting the effects of potential stress than elasticity (a stress must first occur before elasticity can be fully evaluated). The relationship between structural and functional redundancy and their influences on the inertia index is discussed.     

GIS-ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS1

ABSTRACT: Using a geographic information system, a regression model has been developed to identify and to assess potential sources of selenium in the Kendrick Reclamation Project Area, Wyoming. A variety of spatially distributed factors was examined to determine which factors are most likely to affect selenium discharge in tributaries to the North Platte River. Areas of Upper Cretaceous Cody Shale and Quaternary alluvial deposits and irrigated land, length of irrigation canals, and boundaries of hydrologic subbasins of the major tributaries to the North Platte River were digitized and stored in a geographic information system. Selenium concentrations in samples of soil, plant material, ground water, and surface water were determined and evaluated. The location of all sampling sites was digitized and stored in the geographic information system, together with the selenium concentrations in samples. A regression model was developed using stepwise multiple regression of median selenium discharges on the physical and chemical characteristics of hydrologic subbasins. Results indicate that the intensity of irrigation in a hydrologic subbasin, as determined by area of irrigated land and length of irrigation delivery canals, accounts for the largest variation in median selenium discharges among subbasins. Tributaries draining hydrologic subbasins with greater intensity of irrigation result in greater selenium discharges to the North Platte River than do tributaries draining subbasins with lesser intensity of irrigation.     

Market and nonmarket values of the Georgia landscape

Natural landscapes produce goods and services, such as fish, wildlife, recreation, climate control, that are not adequately incorporated in their market values. Contingent Valuation (CV) and Energy Analysis (EA) approaches were used to estimate the nonmarket value of forests in Georgia. Both methods yielded similar estimates of approximately $200 ha^–1, which was 31% of the total market and nonmarket value of forests. Energy analysis was also used to estimate the nonmarket value of the major land uses in Georgia. Relative contributions of nonmarket value to total value ranged from 0.1% for urban areas to approximately 100% for wetlands. For the state as a whole, nonmarket production of natural and developed ecosystems was estimated at $2.6 billion. This value is comparable to annual marketed agricultural ($2.8 billion) and timber ($4.5 billion) production, both very important industries in Georgia. Changing land use patterns in Georgia and elsewhere are likely to be accompanied by shifts in the relative importances of market and non-market values.     

STREAM CHEMISTRY IN THE SOUTHERN BLUE RIDGE: FEASIBILITY OF A REGIONAL SYNOPTIC SAMPLING APPROACH1

ABSTRACT: A pilot study, which was conducted in the Southern Blue Ridge geographical province of the Southeastern U.S., demonstrated the feasibility of a probability-based regional synoptic design for the National Stream Survey, which is a project aimed at estimating the number and percentage of streams in various regions of the U.S. that are acidic or at risk from acid deposition. Estimated population distributions for key chemical variables were not appreciably affected by week-to-week variability in stream chemistry during the spring index period chosen for the study. Differences were observed in estimated acid neutralizing capacity (ANC), nitrate, and pH frequency distributions between spring and summer. Observations made at the downstream node did not represent the chemistry of the entire reach for some variables (ANC and nitrate) as indicated by differences in chemical concentrations between upstream and downstream sampling locations. Coefficients of variation in chemical species were low enough to provide a reasonably stable classification of streams based on ANC. Although median ANC, sulfate, and nitrate concentrations were quite low in the region, the probability of finding streams with ph < 6.3 is less than 1.3 percent at the α= 0.05 confidence level.     

Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments

The destruction of the buildings at the World Trade Center (WTC) complex dispersed dust and debris into the surrounding area. Pulverized building material made up most of the fallout and was intermixed with combustion byproducts of the aircraft and building contents. A study was conducted to confirm the effectiveness of several cleaning procedures in removing WTC-related contamination from lower Manhattan residences. The contaminants included asbestos, lead, dioxin/furans, synthetic vitreous fibers (fibrous glass), and crystalline silica. All cleaning procedures included the common elements of vacuuming and wet wiping with soap and water. This cleaning procedure combination is effective in reducing WTC-related contamination to below health-based benchmarks. Post-cleaning environmental test results suggested that airborne asbestos measurements can be used as a surrogate parameter in clearance determinations.     

Development and applications of a mass spectrometry/mass spectrometry method for the quantification of polychlorinated dibenzo-p-dioxins and dibenzofurans

Mass spectrometry/mass spectrometry (MS/MS) has been demonstrated to be a valuable technique in the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs, PCDFs). In this study, we demonstrate both the value and limitations of high-resolution mass spectrometry (HRMS) and MS/MS in the analysis of PCDDs and PCDFs. We have found that in certain cases, MS/MS can solve analytical problems that cannot be solved by high-resolution mass spectrometry and we demonstrate the reliability and reproducibility of MS/MS in the analysis of PCDDs and PCDFs in environmental matrices.     

Effects of SO2 and NOx emission reductions on PM2.5 mass concentrations in the southeastern United States

Measurements from sites of the Southeastern Aerosol Research and Characterization (SEARCH) program, made from 1998 to 2001, are used with a thermodynamic equilibrium model, Simulating Composition of Atmospheric Particles at Equilbrium (SCAPE2), to extend an earlier investigation of the responses of fine particulate nitrate (NO3-) and fine particulate matter (PM2.5) mass concentrations to changes in concentrations of nitric acid (HNO3) and sulfate (SO42-). The responses were determined for a projected range of variations of SO42- and HNO3 concentrations resulting from adopted and proposed regulatory initiatives. The predicted PM2.5 mass concentration decreases averaged 1.8-3.9 microg/m3 for SO42- decreases of 46-63% from current concentrations. Combining the S042- decrease with a 40% HNO3 decrease from current concentrations (approximating expected mobile-source oxides of nitrogen [NOx] reductions by 2020) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0.2 microg/m3 for three nonurban sites and 0.8-1 microg/m3 for one nonurban and two urban sites. Increasing the HNO3 reduction to 55% (an estimate of adding Clear Skies Phase II NOx reductions) yielded additional incremental reductions of mean predicted PM2.5 mass concentration of 0-0.4 microg/m3. Because of the well-documented losses of particulate NO3- from Federal Reference Method (FRM) filters, only a fraction of these incremental changes would be observed.     

Using satellite imagery to locate innovative forest management practices in Nepal

There is a critical need to locate innovative forest management institutions that significantly impact forest cover change. This research presents an initial "proof of concept" methodology which combines deforestation theory with satellite image change analysis to identify forested areas that, theoretically, should probably not be there. Ten such "forest anomalies" are identified using temporal analysis of Landsat TM imagery of the Chitwan district in Nepal, linked with a GIS database on roads and a visual estimation of topography. A rapid field reconnaissance is undertaken to determine which of these anomalies exhibit interesting forest management innovations. Based on this information, one case is selected for detailed field study: this turns out to be a major case of community forestry and a premier ecotourism initiative that we were not aware of until we undertook this analysis. The utility and limitations of the method are described for monitoring trends in forest cover change.