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171.
Qiu Z 《Environmental management》2003,32(3):299-311
Conservation buffers have the potential to reduce agricultural nonpoint source pollution and improve terrestrial wildlife habitat, landscape biodiversity, flood control, recreation, and aesthetics. Conservation buffers, streamside areas and riparian wetlands are being used or have been proposed to control agricultural nonpoint source pollution. This paper proposes an innovative strategy for placing conservation buffers based on the variable source area (VSA) hydrology. VSAs are small, variable but predictable portion of a watershed that regularly contributes to runoff generation. The VSA-based strategy involves the following three steps: first, identifying VSAs in landscapes based on natural characteristics such as hydrology, land use/cover, topography and soils; second, targeting areas within VSAs for conservation buffers; third, refining the size and location of conservation buffers based on other factors such as weather, environmental objectives, available funding and other best management practices. Building conservation buffers in VSAs allows agricultural runoff to more uniformly enter buffers and stay there longer, which increases the buffers capacity to remove sediments and nutrients. A field-scale example is presented to demonstrate the effectiveness and cost-effectiveness of the within-VSA conservation buffer scenario relative to a typical edge-of-field buffer scenario. The results enhance the understanding of hydrological processes and interactions between agricultural lands and conservation buffers in agricultural landscapes, and provide practical guidance for land resource managers and conservationists who use conservation buffers to improve water quality and amenity values of agricultural landscape. 相似文献
172.
Bennett EM 《Environmental management》2003,32(4):476-487
Understanding the magnitude and location of soil phosphorus (P) accumulation in watersheds is a critical step toward managing runoff of this pollutant to aquatic ecosystems. Here, I examine the usefulness of urban–rural gradients, an emerging experimental design in urban ecology, for predicting extractable soil P concentrations across a rapidly urbanizing agricultural watershed in southern Wisconsin. I compare several measures of an urban–rural gradient to predictors of soil P such as soil type, slope, topography, land use, land cover, and fertilizer and manure use. Most of the factors that were expected to drive differences in soil P concentrations were found to be poor predictors of Bray-1 (extractable) soil P, which ranged from 4 to 660 ppm; while there were several significant relationships, most explained only a small proportion of the variation. A multiple linear regression model captured approximately 37% of the variation in the data using the urban–rural gradient, topography, land use, land cover, manure use, and soil type as predictors. There was a significant relationship between Bray-1 P concentration and each of the urban–rural gradients, but these relationships explained only between 2.6% and 3.3% of the variation in P concentrations. Extractable P concentration in soils, unlike some other ecosystem properties, is not well predicted by urban–rural gradients. 相似文献
173.
174.
Simon M. Munthali 《Natural resources forum》2007,31(1):51-60
Sub‐Saharan Africa continues to face the daunting challenge of alleviating poverty due to slow economic growth. In southern Africa, most countries are adopting policies that promote the integration of biodiversity conservation and rural development to contribute to rural poverty alleviation. Numerous approaches have been undertaken in this endeavour, including Transfrontier Parks (TFPs) and Transfrontier Conservation Areas (TFCAs). This paper discusses some of the limitations of the TFPs. In conclusion I posit that unlike TFPs, which are state controlled and managed, TFCAs, which promote multi‐land use and multi‐stakeholder participation are attainable and have a higher probability of sustaining biodiversity conservation and contributing to the alleviation of rural poverty, if: (i) areas of high biodiversity conservation within communal areas can be identified, zoned and leveraged to biodiversity conservation and managed in partnership between the communities and the private sector; (ii) local communities can secure legal rights to their customary land being devoted to biodiversity conservation and use such pieces of land as collateral in negotiating partnerships with the private sector in developing conservation‐based enterprises; (iii) functional community natural resource governance institutions can be established and empowered to represent their constituencies in securing fair equity from profits made from sustainable use of the conserved biodiversity assets and tourism businesses; (iv) concerted effort can be invested in developing and implementing family planning and fertility reduction strategies that would slow down human population growth to levels that can be sustained by the available natural resources; and (v) if sustainable financing mechanisms can be developed, and the governance of protected areas occurring in the TFCAs can be broadened to include other stakeholders. 相似文献
175.
Gladys Mutangadura 《Natural resources forum》2007,31(3):176-187
The study presented in this article used a combination of key informant interviews and a review and synthesis of existing country level literature to identify the major sources of land tenure insecurity in six Southern African countries: Botswana, Lesotho, Malawi, Mozambique, South Africa, and Zambia. Findings reveal that the main causes of land tenure insecurity experienced in Southern Africa include lack of land rights of minority groups, unclear or overlapping land rights, overcrowding, land alienation into leasehold, insecurity of farm workers and farm labour tenants, inappropriate and exploitative administrative practices, land encroachment and illegal settlers and limited women's land rights. The article presents a summary of land tenure security related initiatives that the study countries have or are in the process of adopting. Analysis of these initiatives shows that tenure reforms have focused on changing the law and rules but little has been done to translate new laws into implementable programs; capacity building; prioritization of resources to support tenure reform; provision of complementary policies and incentives; addressing HIV/AIDS‐land tenure related problems; and monitoring and evaluation. The paper contends that these policy issues should be addressed in order to ensure realization of land tenure security for all. 相似文献
176.
177.
E. Earl Whitlatch Peggy L. Asplund 《Journal of the American Water Resources Association》1981,17(2):310-314
ABSTRACT: The cost of water service to rural residents is very high compared to urban areas. This is true even after subsidization by Farmers Home Administration (FmHA) loans and grants. Capital cost data on 44 projects financed by the Ohio office of the FmHA during the period August 1968 to January 1977 are used to derive cost equations for 26 components of rural water distribution systems. These components represent 92 percent of the capital cost of the pipeline distribution systems studied. The data can be used to economically design rural water supply systems from a capital cost viewpoint. More data are needed on operation and maintenance costs as well as central and cluster well costs before totally economic system designs can be undertaken. 相似文献
178.
Timothy R. Lazaro 《Journal of the American Water Resources Association》1977,13(1):149-151
ABSTRACT: Small, rural communities (less than 2500 population) in general do not have governmental staffs with the breadth required to satisfactorily implement and enforce a drainage ordinance. This fact has serious implications in rural Planning. Within a six-country rural area of Southwest Virginia, the circuit riding town manager program has been successfully conducted. The circuit riding town manager is a planning staff member who acts in the capacity of a town manager (assistant to the mayor) for five small towns, any one of which alone could not afford to support the services of such a professional. This note recommends that a circuit riding technical ordiance administrator program could be developed along the same lines. In this manner, the technical ordinance program for serveral small communities could be successfully implemented. 相似文献
179.
Albert Rango Arthur T. Anderson 《Journal of the American Water Resources Association》1974,10(5):1060-1081
ABSTRACT. The Spring 1973 Mississippi River flood was investigated using remotely sensed data from ERTS-1. Both manual and automatic analyses of the data indicate that ERTS-I is extremely useful as a regional tool for flood management. Quantitative estimates of area flooded were made in St. Charles County, Missouri and Arkansas. Flood hazard mapping was conducted in three study areas along the Mississippi River using pre-flood ERTS-1 imagery enlarged to 1:250,000 and 1:100,000 scale. The flood prone areas delineated on these maps correspond to areas that would be inundated by significant flooding (approximately the 100 year flood). The flood prone area boundaries were generally in agreement with flood hazard maps produced by the U. S. Army Corps of Engineers and U. S. Geological Survey although the latter are somewhat more detailed because of their larger scale. Initial results indicate that ERTS-1 digital mapping of flood prone areas can be performed at 1:62,500 which is comparable to some conventional flood hazard map scales. 相似文献
180.
李志刚 《城市环境与城市生态》1998,11(4):27-30
酒泉地区城镇类型较多,城镇体系中的许多关系需要统筹协调,本文侧重从城镇的规模和空间关系分析,城乡一体化和区一发展,基础产业和环境建设等三个角度,探讨了区域城市可持续发展问题。 相似文献