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51.
随着城市工业与居民生活污水排放量的增加,城市河道水质普遍恶化,部分河道与湖泊水体的污染已达到危害居民健康的程度.我国城市水环境面临着巨大的问题.而呼和浩特作为自治区首府,经过几十年发展,城市建设和经济发展都取得了骄人的成绩,但终究没有逃脱"先污染,后治理"的老路,水污染问题日趋严重,西河水体乌黑发臭,原本是城市灵魂的涓涓清流,变成了我们美丽城市脸上的一道伤疤. 相似文献
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不同植被类型对风沙灾害的响应研究有助于风沙灾害的遥感监测评估和防灾减灾工作。采用传统统计学和空间自相关方法,利用MODIS的每日反射率和土地类型产品,分析了风沙灾害后南疆西部不同植被类型NDVI的变化规律及其空间分布特征。结果表明:风沙灾害后,研究区不同植被类型NDVI的差异在增大,NDVI变化值在一0.3865~0.4148之间,NDVI减小的面积占整个研究区面积的54.98%,变异系数增大值在2.44%~36.75%之间;受到风沙灾害的影响,研究区植被NDVI全局Moran’SI系数从0.7982减小到0.6786,但在空间上仍存在显著的正相关性,具有显著的空间集聚特征;由NDVI差值的局部空间自相关指标集聚图以及不同植被类型NDVI差值的空间关联区域面积百分比,可以发现落叶针叶林和裸地或低植被覆盖地受风沙灾害的影响较小,郁闭灌丛和作物受风沙灾害的影响较大。上述关于风沙灾害后南疆西部不同植被类型的变化及其空间格局的研究结果,不仅证明了防护林的风沙阻挡作用,也可以为风沙灾害的防治工作提供参考依据。 相似文献
54.
Abdul Rahim Hj. Nik Richard Lee J. D. Helvey 《Journal of the American Water Resources Association》1983,19(1):47-50
ABSTRACT: This study tests the hypothesis that climatic data can be used to develop a watershed model so that stream flow changes following forest harvest can be determined. Measured independent variables were precipitation, daily maximum and minimum temperature, and concurrent relative humidity. Computed variables were humidity deficit, saturated vapor pressure, and ambient vapor pressure. These climatic variables were combined to compute a monthly evaporation index. Finally, the evaporation index and monthly precipitation were regressed with measured monthly stream flow and the monthly estimates of stream flow were combined for the hydrologic year. A regression of predicted versus measured annual stream flow had a standard error of 1.5 inches (within 6.1 percent of the measured value). When 10, 15, and 20 years of data were used to develop the regression equations, predicted minus measured stream flow for the last 7 years of record (1972–1978) were within 16.8, 11.5, and 9.7 percent of the measured mean, respectively. Although single watershed calibration can be used in special conditions, the paired watershed approach is expected to remain the preferred method for determining the effects of forest management on the water resource. 相似文献
55.
竞合模式:粤西与海南旅游发展的新思路 总被引:4,自引:0,他引:4
以湛江、茂名、阳江三市为一级核心的粤西沿海旅游区与海南旅游区的主导旅游资源相似且地域临近,存在竞争关系。分析了粤西、海南实施竞合模式所具有的条件,并利用“竞合模式”探讨了粤西沿海旅游区和海南旅游区的竞争与合作关系,以建立粤西—海南旅游体系为目标,提出了合作战略,以期增强整体的竞争实力,促进旅游业的发展。 相似文献
56.
Analysis of a rural water supply project in three communities in Mali: Participation and sustainability 总被引:1,自引:0,他引:1
This paper presents a qualitative assessment of the participatory water management strategies implemented at the community level in rural Mali through a water supply project — The West Africa Water Initiative (WAWI) — coordinated by World Vision International, a non‐governmental and humanitarian organization. Data for the study were generated through a combination of primary and secondary sources in three villages. Results of the study indicate that while community‐based rural water supply is a positive step in responding to the needs of rural Malians, the installation of boreholes with hand pumps informed merely by consultative participatory approaches and limited extension involvement will not necessarily proffer sustainable rural water supply in the region. A “platform” approach to rural water supply management that can mobilize the assets and insights of different social actors to influence decision making at all stages, including the design and choice‐of‐technology stages, in water supply interventions is instead advocated. 相似文献
57.
西部大开发中的四川猕猴桃资源优势 总被引:4,自引:0,他引:4
通过对四川省猕猴桃资源现状的分析,阐述了四川猕猴桃的资源优势及其人工栽培现状,提出了在西部大开发中发展四川猕猴桃产业化的道路。 相似文献
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59.
Oluyede Clifford Ajayi Festus K. Akinnifesi Gudeta Sileshi Adeola O. Ajayi 《Natural resources forum》2009,33(2):111-122
In most of sub‐Saharan Africa, where the agricultural sector experiences dismal performance and is characterized by a gloomy picture, the cotton sub‐sector in Côte d’Ivoire is often mentioned as a “success story” given the spectacular rise in the quantity of cotton production and the profile of the crop within the farming system. What are the historical and political antecedents of the development of cotton and the factors responsible for the feat accomplished in the midst of general failures in the same continent? To what extent can cotton be regarded as a “success story” and, what lessons can be drawn for agricultural development strategies based on the Ivorian case study? This paper traces the historical and socio‐political background of cotton development in Côte d’Ivoire and identifies key policy and institutional interventions that have influenced the rise of cotton production and its emergence as the dominant crop in the farming systems of the country. Four stages in Ivorian cotton development are identified: planning, take off, crisis and the renaissance phases. The study demonstrates how a combination of good planning, technological advancement and appropriate policy and institutional conditions have contributed significantly to the rise of cotton production and its influence on the agricultural economy of northern Côte d’Ivoire. The study also highlights how the sustainability of agricultural development has been impacted by domestic and international policies and political events over which smallholder farm families have little control, and can at best only respond to. Important questions about cotton development in Côte d'Ivoire are raised that need to be answered before the program can be categorized conclusively as a success story. The study shows that there are no quick fixes to agricultural development in the sub‐region. Rather, good planning and putting the necessary building blocks in place are important prerequisites. It is recommended that agricultural development efforts in the continent take cognizance of the complexity of the sector and address the inter‐relationships that exist among the technical, policy, market and institutional factors that combine individually and collectively to influence African agriculture. 相似文献
60.
可持续发展:西部大开发的基本理念 总被引:8,自引:0,他引:8
陈德敏 《中国人口.资源与环境》2000,10(2):46-48
本文从西部大开发的深远意义出发 ,探讨西部大开发的约束条件 ,进而讨论可持续发展是西部大开发的基本理念 ,并以可持续发展为指导原则提出建议。 相似文献