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271.
Pamela J. Edwards James N. Kochenderfer Donald W. Seegrist 《Journal of the American Water Resources Association》1991,27(2):265-274
ABSTRACT: Stream water chemistry was monitored on two watersheds on the Fernow Experimental Forest in north-central West Virginia to determine the effects of forest fertilization on annual nutrient exports. Ammonium nitrate and triple superphosphate were applied simultaneously at rates of 336 kg ha?1 N and 224 kg ha?1 P2O5, respectively, which are similar to rates used in commercial forest operations. The treatment significantly increased outputs of several ions. Annual outputs of nitrate N increased as much as 18 times over pretreatment levels, and calcium and magnesium increased as much as three times over pretreatment levels the first year after fertilization. Outputs for these nutrients were elevated for all three post-treatment years. Although nitrate N increased significantly, only about 20 percent of the applied fertilizer was accounted for in stream water exports. Outputs of phosphate P declined following fertilization, probably because the watersheds are phosphorus deficient, but by the third year, they slightly exceeded predicted values. Estimated nutrient losses to deep seepage were substantial, especially on the leakier south-facing catchmeat, on which some nutrient losses were equal to or greater than those in stream water. When the nutrient exports associated with both stream discharge and ground water recharge were combined, the percentages of applied N that were lost were similar on the two watersheds, averaging 27.5 percent. Less than 1 percent of the applied P was lost from either watershed in the combination of streamflow and deep seepage. 相似文献
272.
J. R. Crabtree N. A. Chalmers Z. E. D. Appleton 《Journal of Environmental Planning and Management》1994,37(4):415-429
This paper considers the external costs of public access on privately‐owned farm and estate land in Scotland. The increased costs and reductions in income associated with public access are found to be highly variable and site‐specific, with the main effects on land in areas of high population density or high scenic quality, or with recreational attributes. Although costs were on average higher for estates, reflecting their larger area and recreational potential, on a per‐hectare basis the costs of access were greater for the farm sector. Whilst much of the public access exists through de facto rights on open‐access land, there was evidence for an increasing commercialization of open‐air recreation, particularly with respect to more specialized activities. The discussion considers the extent to which the costs of access for land managers are reflected in policies determining the public provision of countryside access. 相似文献
273.
274.
Peter Wathern Stephen N. Young Ian W. Brown Dawn A. Roberts 《Environmental management》1987,11(1):7-12
The EEC Shellfish Directive is a policy designed to protect and, where necessary, improve the quality of designated shellfish waters. Its implementation within the UK, however, has had no effect upon water quality for two reasons. First, the policy has important defects, having ambiguities concerning public health provisions and lacking designation criteria. Second, UK government has sought to achieve formal compliance, while at the same time ensuring that its full financial impact on public expenditure has been contained. Consequently, only those fisheries which already comply with water quality standards have been designated. Within Wales, one fishery has been designated, while other, commercially more important, but grossly contaminated shellfisheries have not. 相似文献
275.
Summary In the present paper efforts have been made to identify an environmentally sustainable and economically gainful strategy for agricultural development in the Himalayan region in Uttar Pradesh State, India. In the underdeveloped rural habitat that exists, a strategy, where the economics of environmentally sustainable development can be studied, is urgently required. The findings have been based on an empirical investigation of 150 sampled households spread over fifteen villages. It was found that the state of Himalayan agriculture and allied activities was in a critical condition, requiring urgent attention in order to improve the human environment. Suggested viable improvements in Himalayan agricultural development may be grouped into four categories, viz., an expansion of the cultivated area, where the land use pattern and other factors are discussed; full utilisation of irrigation potentialities, in which water management is discussed; improvement in the cropping pattern, where the whole system of cropping is analysed; and modifications in the use of agricultural appliances, specially in hoeing, ploughing and inter-culturing implements. Based on a critical analysis of these four identified aspects, economically viable, ecologically sound and socially justified environmental planning may be effectively framed.Dr H.C. Pokhriyal is Head of the Department of Economics at Garhwal University Campus, Tehri, and Dr N.S. Bist is Professor and Head of the Department of Economics at Garhwal University, Srinagar Garhwal, Himalaya, U.P., India. 相似文献
276.
Paul N. Wilson Teddy J. Goldammer James C. Wade 《Journal of the American Water Resources Association》1988,24(1):1-9
ABSTRACT: Urban wastewater can be a valuable source of water and plant nutrients for agricultural producers, particularly in arid regions. The scientific literature reveals cautious optimism concerning the biological, institutional, and economic viability of irrigating crops with secondary-treated effluent. A derived effluent demand function for agricultural producers near Tucson, Arizona, reveals a potential annual demand of 11,000 acre-feet under present price and proposed delivery system conditions. In this case, wastewater could be exchanged for ground water and both the urban and rural areas would gain. 相似文献
277.
In many locations, regulatory agencies do not permit tree planting above landfills that are sealed with a capping clay, because
roots might penetrate the clay barrier and expose landfill contents to leaching. We find, however, no empirical or theoretical
basis for this restriction, and instead hypothesize that plant roots of any kind are incapable of penetrating the dense clays
used to seal landfills. As a test, we excavated 30 trees and shrubs, of 12 species, growing over a clay-lined municipal sanitary
landfill on Staten Island, New York. The landfill had been closed for seven years, and featured a very shallow (10 to 30-cm)
soil layer over a 45-cm layer of compacted grey marl (Woodbury series) clay. The test plants had invaded naturally from nearby
forests. All plants examined—including trees as tall as 6 m—had extremely shallow root plates, with deformed tap roots that
grew entirely above and parallel to the clay layer. Only occasional stubby feeder roots were found in the top 1 cm of clay,
and in clay cracks at depths to 6 cm, indicating that the primary impediment to root growth was physical, although both clay
and the overlying soil were highly acidic. These results, if confirmed by experimental research should lead to increased options
for the end use of many closed sanitary landfills. 相似文献
278.
279.
N. Foroud R. S. Broughton G. L. Austin 《Journal of the American Water Resources Association》1984,20(1):87-91
ABSTRACT: The effects of a moving rainstorm on flood runoff characteristics were investigated. A flood hydrograph simulation model called “FH-Model” and a natural watershed were used. A hypothetical rainstorm of 50 years recurrence interval, 75 mm depth, and 4 hours duration was used to show the effects of velocity and direction of the moving rainstorm on the runoff characteristics. Compared with an equivalent stationary rainstorm (ESRS), the peak flow caused by a rainstorm moving in a downstream direction with a speed equal to channel velocity, V, was 27.5 percent higher and the peak flow caused by the same rainstorm moving in an upstream direction was 21.7 percent smaller. These percentages reduced to 10.5 percent and 8.6 percent for storms moving downstream and upstream, respectively, at three times the channel velocity, 3V. There were negligible differences in the time of peak, Tp between runoff caused by storms moving downstream and runoff produced by ESRS. However, Tp for a storm moving upstream at V velocity was 82 percent higher than that produced by ESRS, but was reduced to 27 percent higher when the storm velocity was 3V. 相似文献
280.
This paper describes the primary energy resources of New Zealand and their relative importance. It describes the principal legislation that provides environmental protection and public participation with which State and private agencies are bound to comply. The paper then discusses air pollution in further detail and cites three examples where there is cause for concern. By international standards, air pollution is not a serious problem in New Zealand and so the economic consequences have received little attention Two simple examples are cited. A map showing the main centers and the location of facilities referred to in the text is included 相似文献