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321.
322.
Walter H. Bumgardner Lawrence R. Klar Aldo Glirin 《Journal of the American Water Resources Association》1980,16(2):279-284
ABSTRACT: There is considerable controversy inthe Northeast surrounding the extent to whcih public drinking water reservoirs should be used for recreational purposes. This paper reports the results of two integrated studies of (1) recreation users of Quabbin Reservation, the largest inland water source in New England and (2) the general public of Massachusetts. Data were obtained by conducting on-site interviews of Quabbin users and through state-wide telephone interviews of the general public; both studies focused on assessing attitudes toward the recreational use of drinking water reservoirs in Massachusetts. Unlike the findings of a 1969 study conducted by Baumann, results showed that the majority of Massachusetts residents do not favor recreation-prohibiting laws for most activities. Most favored at least moderate use of reservoirs for recreational purposes. In addition, over all views were not as restrictive as present legislation would suggest. Finally, these findings suggest that current recreation-prohibiting laws should be reassessed in light of pugblic opinion which favors the use of these valuable resources. 相似文献
323.
324.
David A. Rickert Walter G. Hines Stuart W. McKenzie 《Journal of the American Water Resources Association》1975,11(5):1013-1039
ABSTRACT: The U.S. Geological Survey is now (1975) conducting an intensive river-quality assessment of the Willamette River basin, Oregon. The objectives are to (1) define a practical framework for conducting comprehensive river-quality assessments, (2) develop and document methods for evaluating basin-development alternatives in terms of potential impacts on river quality, (3) determine the kinds and amounts of data required to adequately assess various types of river-quality problems, and (4) apply the framework, data, and methods to assess the existing or potential river-quality problems of the Willamette River basin. This paper covers objectives 2, 3, and 4 by examining the rationales behind the selection and application of methods and the design of data programs for assessing specific river-quality problems. The rationales are those developed for assessing (1) the effect of population and industrial growth and resulting waste discharges on river-dissolved oxygen, (2) the potentially harmful effects on land and river quality of accelerated erosion resulting from intensive land-use development, and (3) the potential for nuisance algal growth. The goal of the assessment program and, thus, the context of the rationales is to provide technically sound information that is appropriate and adequate for resource planning and management. 相似文献
325.
Transport of lead and diesel fuel through a peat soil near Juneau, AK: a pilot study 总被引:3,自引:0,他引:3
Deiss J Byers C Clover D D'Amore D Love A Menzies MA Powell J Walter MT 《Journal of contaminant hydrology》2004,74(1-4):1-18
A set of peat column experiments was used to determine the transport potential of lead (Pb) and diesel range organics (DRO) in palustrine slope wetlands near Juneau, AK. This project is important to southeast Alaskan communities because limited land resources are forcing development of regional wetlands. This study was instigated by concerns that proposed modifications to a nearby rifle range using DRO-contaminated soil posed a potential risk to an anadromous fish-bearing stream 250 m from the site. Three pairs of peat columns were extracted from the rifle range for analysis, one pair along and two pairs across the natural bedding planes of the soil. One column in each pair was spiked with Pb and DRO and the other was used as a control. Approximately 1-year worth of water (171 cm) was passed through each column and leachate was collected at regular intervals. The results showed that substantial DRO transport only occurred along the bedding planes. Leads was surprisingly mobile, both along and across the bedding planes with estimated soil-water partition coefficients several orders of magnitude lower than commonly published values, probably because the peat was heavily Pb-loaded by lead from bullets and because the peat's acidic, organic-rich environment enhanced Pb mobility. The chemical outflow behavior agreed with a simple macropore transport model. These results underscore the need for caution when developing regional wetlands. 相似文献
326.
Gerald T. Ankley Nelson A. Thomas Dominic M. Di Toro David J. Hansen John D. Mahony Walter J. Berry Richard C. Swartz Robert A. Hoke A. Wayne Garrison Herbert E. Allen Christopher S. Zarba 《Environmental management》1994,18(3):331-337
Due to anthropogenic inputs, elevated concentrations of metals frequently occur in aquatic sediments. In order to make defensible
estimates of the potential risk of metals in sediments and/or develop sediment quality criteria for metals, it is essential
to identify that fraction of the total metal in the sediments that is bioavailable. Studies with a variety of benthic invertebrates
indicate that interstitial (pore) water concentrations of metals correspond very well with the bioavailability of metals in
test sediments. Many factors may influence pore water concentrations of metals; however, in anaerobic sediments a key phase
controlling partitioning of several cationic metals (cadmium, nickel, lead, zinc, copper) into pore water is acid volatile
sulfide (AVS). In this paper, we present an overview of the technical basis for predicting bioavailability of cationic metals
to benthic organisms based on pore water metal concentrations and metal-AVS relationships. Included are discussions of the
advantages and limitations of metal bioavailability predictions based on these parameters, relative both to site-specific
assessments and the development of sediment quality criteria. 相似文献
327.
Most nonpoint source pollution problems on forest lands can be controlled by careful planning and management of specific critical areas. Critical areas include sites with high mass and surface erosion hazards, overland flow areas, and the riparian zone. Some guides for identifying critical areas are presented along with examples of land-use constraints that might be applied. 相似文献
328.
Summary Thermal preferences of well-fed and food-limited fire ant colonies (Solenopsis invicta) were studied in relation to colony growth and metabolic costs. The growth curve for well-fed colonies was strongly skewed toward warmer temperatures with maximal growth occurring near 32° C (Fig. 2A). The growth curve for food-limited colonies was skewed toward cooler temperatures with maximal colony size occurring around 25° C (Fig. 2B). Food-limited colonies apparently grew larger at cooler temperatures because metabolic costs of workers were reduced. A series of binary choice tests confirmed three predictions concerning fire ant thermal preferences (Figs. 3–4). First, well-fed colonies preferred brood temperatures very near the optimum for colony growth (31° C versus 32° C). Colonies were also able to select appropriate suboptimal growth temperatures when the optimal range was unavailable. Secondly, as predicted, a large percentage of colony workers ( 30% in well-fed colonies) consistently chose cooler temperatures than those selected for the brood. This strategy probably increases longevity of workers not directly associated with brood care. Thirdly, food-limited colonies preferred cooler temperatures than well-fed colonies. Metabolic costs of food-limited colonies were reduced by approximately 7% because of (1) slightly cooler brood temperatures (30° C versus 31° C) and because (2) an additional 20–30% of the workers selected cooler temperatures. The addition of excess food reversed food-limited thermal preferences within 12 h for the brood (Fig. 5) and several days for the workers. Contrary to expectations, thermal preferences for brood in food-limited colonies did not match the food-limited growth curve, perhaps because fire ant colonies can choose to rear brood at warm temperatures while maintaining accumulated colony biomass at cooler temperatures.
Correspondence to: S.D. Porter 相似文献
329.
Jochem F. M. van der Waals Walter J. V. Vermeulen 《Journal of Environmental Planning and Management》2002,45(4):549-569
This paper investigates the potential of a method for participatory policy making in the field of carbon dioxide (CO 2 ) reduction in housing: the CO 2 reduction workshop. This innovative method aims to involve relevant actors at an early stage of urban development and to formulate common ambitions for CO 2 reduction. Special attention is paid to the inputting of information about options for CO 2 reduction. The workshop was organized and evaluated in two planning processes for new housing estates in the Netherlands. The evaluation addresses the design of the workshop, the utilization of knowledge in the process, the effects of the workshop on the commitment and knowledge of the participants and the effects on the wider planning process. 相似文献
330.
JoAnn M. Hanowski Peter T. Walter Gerald J. Niemi 《Journal of the American Water Resources Association》2002,38(3):633-639
ABSTRACT: Forest buffers adjacent to water bodies are widely prescribed in forest management to protect ecological functions of riparian systems. To date, buffers have been applied on the landscape uniformly without quantifying their effectiveness or the effects they have on landscape characteristics. Our objective was to quantify landscape characteristics (amount of edge and interior forest) when buffers were applied to water bodies in a 100 by 100 km area of northern Minnesota. We used a Landsat classified image in a geographic information system platform to apply two buffer widths ?28.5 m and 57 m — to water bodies, including nonforested wetlands, intermittent or perennial streams, and lakes. A total of 107,141 ha (18.3 percent) of the forest area was adjacent to and within 28.5 m of these water bodies, while 201,457 ha of forest was within 57 m, representing 34.4 percent of the total forest area. Imposing a 28.5 m buffer on water bodies increased the amount of edge and interior forest in the study area. When water bodies were buffered with a 57 m forest strip, we found a slight increase in forest edge from the current condition, and this buffer width resulted in the largest amount of interior forest. Interior forest increased with the 57 m buffer due to the density of water bodies in this region; adjacent water bodies coalesced when buffers were applied and formed isolated forest islands that contained forest interior habitat. Instead of wholesale application of set width riparian buffers, we suggest that ecological conditions of riparian areas be evaluated on a site level and that areas that currently provide important riparian conditions be maintained on the landscape with appropriate management practices. 相似文献