We assessed methylmercury (MeHg) concentrations across multiple ecological scales in the Edisto (South Carolina) and Upper Hudson (New York) River basins. Out-of-channel wetland/floodplain environments were primary sources of filtered MeHg (F-MeHg) to the stream habitat in both systems. Shallow, open-water areas in both basins exhibited low F-MeHg concentrations and decreasing F-MeHg mass flux....

We use hedonic property models to estimate the changes in implicit flood risk premium following a large flood event. Previous studies have used flood hazard maps to proxy flood risk. In addition to knowing whether a property lies in the floodplain, we use a unique data set with the flood inundation map. We find that the price discount for properties in the inundated area is substantially larger...

Integrating FEMAs Enhanced DFIRMDB Model With ESRI's Arc Hydro Data Model Track: Water Resources Author(s): Mark Aurit, Chas Crandel, Howard Davis Advancements in technology, such as the release of ArcGIS 8, the geodatabase model, and the introduction of the Arc Hydro data model will allow for the integration of GIS technology and floodplain management. The Arc Hydro data model was designed to ...

Cyclopid copepods from samples of fauna associated with aquatic macrophytes and plancton obtained in lotic and lentic environments were obtained from the upper Paraná River floodplain (in the states of Paraná and Mato Grosso do Sul, Brazil). Macrophytes were collected in homogeneous stands and washed. Plankton samples, taken from the water column surface and bottom, were obtained using a motor ...

We evaluate experimentally the effect of a sequential disturbance-desiccation-on the structure and dynamics of a periphytic algal community in a semilotic environment of the Upper Paraná River floodplain. We tested the hypothesis that the presence of recurrent disturbances have a direct negative effect on the attributes of the periphyton community. The sequential effect of desiccation on the pe...

Spatial and temporal patterns of plankton ciliates species composition in the Paraná River floodplain were investigated. Samplings were carried out in twelve environments in two distinct hydrological periods (limnophase and potamophase). A total of 61 species of ciliates were recorded, and among them 21 are classified as pelagic while 40 are considered preferentially as littoral species. The re...

To meet the increasing demand for wood and wood products, the Southern Hardwoods Laboratory is investigating silvicultural techniques such as fertilization. Sweetgum, water oak, and willow oak have responded to N and NPK on clay soils of the Mississippi River floodplain. Yellow-poplar growth has been improved by NPK fertilizers on eroded sites in the Silty Uplands, and in the greenhouse sycamor...

Active and semi-active anastomosing Holocene channels upstream of the delta in the lower valley of the meandering Neches River in southeast Texas represent several morphologically distinct and hydrologically independent channel systems. These appear to have a common origin as multi-thread crevasse channels strongly influenced by antecedent morphology. Levee breaching leads to steeper cross-vall...

This study presents an advanced remote sensing-based steady-state flood model to improve flood management strategies. The REFIX (Regression and Elevation based Flood Information eXtraction) model is based on regression analysis and uses a remotely sensed flood extent and a high-resolution floodplain DEM (Digital Elevation Model) to estimate water heights for a given flood event. In some cases, ...