RELATIONSHIP BETWEEN ANNUAL RUNOFF AND WATERSHED AREA FOR THE EASTERN UNITED STATES1

ABSTRACT: As part of the U.S. Environmental Protection Agency's effort to determine the long-term effects of acidic deposition on surface water chemistry, annual runoff was estimated for about 1000 ungaged sites in the eastern U.S. using runoff contour maps. One concern in using contour maps was that a bias may be introduced in the runoff estimates due to the size of the 1000 ungaged sites relative to the size of the watersheds used in developing the maps. To determine if a bias was present the relationship between the annual runoff (expressed as depth) and the watershed area for the Northeast (NE) and Southern Blue Ridge Province (SBRP) was tested using five regional data bases. One short-term data base (1984 Water Year, n = 531) and two long-term data bases (1940–57, n = 134 and 1951–80, n = 342) were used in the NE. In the SBRP one short-term database (1984 Water Year, n = 531) and one long-term data base (1951–80, n = 60) were used. For the NE and the SBRP, runoff was not directly correlated with watershed area using the five regional databases. Also, runoff normalized by precipitation was not related to watershed area.     

Increasing seat belt use through PI&E and enforcement: The Thumbs Up campaign

Campaigns to increase seat belt use have been effective in controlled environments, in small geographic areas, in primary enforcement states, and when conducted in conjunction with the enactment of seat belt legislation. The Thumbs Up project was undertaken to determine if belt use could be facilitated in less advantageous conditions. A 3-month campaign to increase seat belt use was conducted in two sites, each consisting of two Florida counties. At its conclusion, the Thumbs Up project did not yield an overall increase in seat belt use across the two sites. However, observed seat belt use and the number of seat belt citations issued increased significantly in one site. The results are discussed in terms of the two components necessary for a successful campaign: public information and education, and enforcement. Further, recommendations for conducting successful community-based seat belt interventions are offered.     

Grass carp status in the United States: A review

Grass carp (Ctenopharyngodon idella Val.) were introduced into the United States in 1963 as potential biological control agents for nuisance aquatic weeds. Since that time an oftentimes bitter controversy has raged over its effects on sportfishing, and its possible natural reproduction and naturalization in North America. This review considers the history, ecology, and present status of grass carp in the United States in light of the voluminous scientific research conducted since its importation. Particular attention is given to the role of grass carp in the fisheries management plans of Arkansas. Recent development of a sterile, triploid grass carp hybrid may lead to widespread use of grass carp to control nuisance aquatic weeds in culturally eutrophicated waters of the United States.     

MULTISCALE RIVER ENVIRONMENT CLASSIFICATION FOR WATER RESOURCES MANAGEMENT1

ABSTRACT: River Environment Classification (REC) is a new system for classifying river environments that is based on climate, topography, geology, and land cover factors that control spatial patterns in river ecosystems. REC builds on existing principles for environmental regionalization and introduces three specific additions to the “ecoregion” approach. First, the REC assumes that ecological patterns are dependent on a range of factors and associated landscape scale processes, some of which may show significant variation within an ecoregion. REC arranges the controlling factors in a hierarchy with each level defining the cause of ecological variation at a given characteristic scale. Second, REC assumes that ecological characteristics of rivers are responses to fluvial (i.e., hydrological and hydraulic) processes. Thus, REC uses a network of channels and associated watersheds to classify specific sections of river. When mapped, REC has the form of a linear mosaic in which classes change in the downstream direction as the integrated characteristics of the watershed change, producing longitudinal spatial patterns that are typical of river ecosystems. Third, REC assigns individual river sections to a class independently and objectively according to criteria that result in a geographically independent framework in which classes may show wide geographic dispersion rather than the geographically dependent schemes that result from the ecoregion approach. REC has been developed to provide a multiscale spatial framework for river management and has been used to map the rivers of New Zealand at a 1:50,000 mapping scale.     

US Government Natural Disaster Assistance: Historical Analysis and a Proposal for the Future

Governments often provide grants or low-interest loans to disaster victims. Yet these programmes have proven to be quite costly. In addition, questions have been raised about associated behavioural incentives. Conceptually, government disaster insurance programmes should be more efficient, consistent and equitable than ex post facto disaster relief in the form of grants and loans. Yet the performance of government disaster insurance programmes has been mixed, at best. This article reviews the history of US federal natural disaster assistance to individuals and concludes with a recommendation for a new government role in the provision of disaster insurance.     

Field trial of a new aeration system for enhancing biodegradation in a biopile

The influence of a new aeration system on the biopile performance was investigated. The purpose was to increase biodegradation efficiency by optimising airflow through the pile. During a 1-month field trial, the performance of a new system using two perforated vertical pipes with wind-driven turbines was compared with that of a standard pile configuration with two horizontal perforated pipes. Both piles were composed of a similar mix of diesel-contaminated soils, woodchips, compost and NPK fertiliser. Hydrocarbons were recovered using solvent extraction, and determined both gravimetrically and by gas chromatography. Total heterotrophs, pH and moisture content were also assessed. Air pressure measurements were made to compare the efficiency of suction in the pipes. Results at the end of the experiment showed that there was no significant difference between the two piles in the total amount of hydrocarbon biodegradation. The normalised degradation rate was, however, considerably higher in the new system than in the standard one, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile. The pressure measurements showed a significant improvement in the suction produced by the new aeration system. However, many factors other than the airflow (oxygen supply) may influence and limit the biodegradation rates, including moisture content, age of contaminants and the climatic conditions. Additional experiments and modelling need to be carried out to explore further the new aeration method and to develop criteria and guidelines for engineering design of optimal aeration schemes in order to achieve maximum biodegradation in biopiles.     

An approach to tree thinning to structure southern African savannas for long-term restoration from bush encroachment

Due to bush encroachment the grazing capacity of large areas of the southern African savanna has declined, often to such an extent that many previously economic livestock properties are now no longer economically viable. Attempts at restoring encroached areas by the removal of some or all of the woody plants will normally result in an increase of grass production and thus also the grazing capacity. However, the results of woody plant removal may differ between vegetation types, with the outcome determined by both negative and positive responses to tree removal. The rapid establishment of tree seedlings after the removal of some or all of the mature woody plants may reduce the effective time span of restoration measures. In many cases the resultant re-establishment of new woody seedlings may in time develop into a state that is worse than the original state. This paper is an attempt to summarize existing knowledge on the importance of woody plants in savanna and explore measures, based on ecosystem dynamics, which can be utilized to restore encroached areas more successfully. It is hypothesized that a more stable environment can be created by maintaining or restoring savanna structure (large trees). In a structured savanna, large trees are able to suppress the establishment of new seedlings, while maintaining the other benefits of woody plants like soil enrichment and the provision of food to browsing herbivore species. Effective restoration of encroached areas should not be considered a once-off event, but rather a long-term commitment.