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1.
Desert riparian forest colonization in the lower reaches of Tarim River based on remote sensing analysis 总被引：1，自引：0，他引：1
Guilin Liu Alishir Kurban Huanming Duan Umut Halik Abdimijit Ablekim Luocheng Zhang 《Environmental Earth Sciences》2014,71(10):4579-4589
The ecological water conveyance project that pipes water from Daxihaizi reservoir to lower reaches of Tarim River has been implemented ten times since 2000. After ecological water conveyance, restoration has taken place for vegetation along the dried-up lower reaches of the Tarim River. The changes of vegetation fluctuated yearly due to ecological water conveyance. In order to reveal the detailed process of vegetation changes, remote sensing images from 1999 to 2010 were all classified individually into vegetated and non-vegetated areas using the soil-adjusted vegetation index threshold method. Then inter-annual changes of vegetation over a period of 12 years were obtained using a post-classification change detection technique. Finally, spatial–temporal changes distribution of vegetation cover and its response to ecological water conveyance were analyzed. The results indicate: (1) vegetation area increased by 8.52 % overall after ecological water conveyance. Vegetation between 2003 and 2004 increased dramatically with 45.87 % while vegetation between 2002 and 2003 decreased dramatically with 17.83 %. (2) Vegetation area gain is greater than vegetation loss during 1999–2000, 2001–2002, 2003–2004 and 2009–2010 periods. Although vegetation restoration is obvious from 1999 to 2010, vegetation loss also existed except for the periods above. It indicates that vegetation restoration fluctuated due to ecological water conveyance. (3) Spatial distribution of vegetation restoration presented “strip” distribution along the river and group shaper in the lower terrain area, while spatial distribution of vegetation loss mainly located in the upper reaches of river and area far away from the river. (4) Vegetation restoration area had a positive relative with total ecological water conveyance volume. The scheme and season of ecological water conveyance had also influenced the vegetation restoration. The vegetation change process monitoring, based on continuous remote sensing data, can provide the spatial–temporal distribution of vegetation cover in a large-scale area and scientific evidences for implementing ecological water conveyance in the lower Tarim River. 相似文献
2.
Assessment of ecological flow rate by flow duration and environmental management class in the Geum River, Korea 总被引：1，自引：1，他引：0
This study attempted to analyze flow duration in a basin using a method to estimate environmental flow developed by the International Water Management Institute, and simulate the effects of runoff characteristics unique to a river and flow variability due to basin developments on aquatic ecosystems. To do so, KModSim, a simulation model for basin-wide water distribution, was used to assess flow duration in the Geum River basin, one of the four major river basins in Korea, by environmental management class (EMC). Flow duration curves by EMC at Sutong and Gongju sites were derived on the basis of natural flow in the Geum River basin. As a result, they were found to be consistent with the results of previous studies. Time series of mean monthly flow data by EMC were plotted together with those of simulated flow data by reservoir operation scenario; Sutong and Gongju points both showed flow behaviors corresponding almost to “A” in EMC. In addition, the characteristics of habitats by species of fish were identified through monitoring fish habitat at the Sutong site, so that optimal ecological flow rate was estimated. For this purpose, relations between flow discharge and weighted usable area for Coreoleuciscus splendidus and Pseudopungtungia nigra were projected using physical habitat simulation system, and EMCs consistent with flow duration curves (estimated taking in-stream flow) were assessed. The results or findings reported in this study are expected to serve as basic data for making a plan to efficiently monitor and manage aquatic ecosystems in the Geum River basin. 相似文献
3.
公元前256年建立的四川都江堰水利枢纽工程是世界历史上至今仍在发挥巨大作用的最古老的水利工程之一.但是随着工程基础设施的老化,生态环境的恶化,周边地区工农业的过度开发,原有的传统水利发展模式已经不能适应都江堰灌区当前和未来的发展需求.因此,提出了一个以可持续发展思想为指导的、有明确发展目标、有总体发展构架的、又能对其进行实施评估的都江堰水利发展战略框架以及与之相适应的实施对策.用以推动都江堰灌区水利可持续发展的进程. 相似文献
4.
Maarten Wolsink 《Geoforum》2006,37(4):473-487
This article describes the turn to new integrative water management strategies in the Netherlands. It illustrates that some of the new and the general objectives and principles are not easily applied in practice. First, the article focuses on the development of integrative management of water and spatial development. A main policy line, the ‘Room for the River’ directive, was originally an ad hoc reaction to unexpected floods, but accompanied by other policy reforms it grew into an application of the river basin approach with an emphasis on its spatial consequences. The resulting Space-Water-Adjustment Management Principle (SWAMP) emphasizes the mutual adjustments in policy that must be made in both water policy and spatial development. Officially, water is proclaimed as an ordering element, yet actual spatial developments still follow lines of economic and social priorities as executed by institutional powers. Three case studies are presented to illustrate the emergence of new principles and governance issues linked to these management approaches. In practice, the paper concludes, spatial planning and land use decisions show a centralization tendency that is not in line with the proclaimed prevalence of local identity, resilience and open decentralized and deliberative governance in the SWAMP-based integrated river basin management. 相似文献
5.
Larry R. Brown William A. Bennett R. Wayne Wagner Tara Morgan-King Noah Knowles Frederick Feyrer David H. Schoellhamer Mark T. Stacey Michael Dettinger 《Estuaries and Coasts》2013,36(4):754-774
Changes in the position of the low salinity zone, a habitat suitability index, turbidity, and water temperature modeled from four 100-year scenarios of climate change were evaluated for possible effects on delta smelt Hypomesus transpacificus, which is endemic to the Sacramento–San Joaquin Delta. The persistence of delta smelt in much of its current habitat into the next century appears uncertain. By mid-century, the position of the low salinity zone in the fall and the habitat suitability index converged on values only observed during the worst droughts of the baseline period (1969–2000). Projected higher water temperatures would render waters historically inhabited by delta smelt near the confluence of the Sacramento and San Joaquin rivers largely uninhabitable. However, the scenarios of climate change are based on assumptions that require caution in the interpretation of the results. Projections like these provide managers with a useful tool for anticipating long-term challenges to managing fish populations and possibly adapting water management to ameliorate those challenges. 相似文献
6.
Riaz Hossain Khan Muhammad Qumrul Hassan Mohammad Saiful Islam 《Environmental Earth Sciences》2013,69(8):2499-2512
Water quality and hydrochemistry of Shariatpur district were evaluated in terms of hydrochemical composition and some important physico-chemical parameters. The groundwater of the study area is good for drinking, domestic as well as for irrigation purposes. Among the major ions, shallow tube well waters give higher concentration of Ca2+ which ranges from 24 to 260 mg/L. The deep tubewell waters show higher concentration of Na+ which varies from 74 to 582 mg/L during dry season. Among the trace elements most of the shallow aquifer samples show higher concentration of Fe2+, Mn2+ and As. Concentration of Fe2+ varies from 0.655 to 18.8 mg/L, and Mn2+ from trace to 0.868 mg/L during dry period. Hydrochemical analyses reveal significant seasonal variation in water quality of shallow aquifer. Both the shallow aquifer and the surface water of the study area are predominantly of Ca–Mg–HCO3 type, while the deep aquifer water is mainly of Na–K–Cl–SO4 type with slight inclination to Ca–Mg–HCO3 type. The study area is suitable for groundwater development if comprehensive and holistic approaches towards water resource management are taken into consideration. 相似文献
7.
地下水具有重要的生态价值,地下水生态系统中的地下水位、水质和包气带含水率与含盐量的变化驱动着表生生态格局的演变,但目前对各变量的生态阈值研究尚处于起步阶段,理论与方法体系还不完善。以保定平原区为例,采用地下水位及地下水生态环境的历史回归法、GIS法、差分网格计算法等方法,从时空角度分析了地下水位变化的驱动力以及生态效应,在此基础上确定不同水文地质单元的生态水位阈值。研究表明:（1）20世纪50—60年代,研究区依赖于地下水的生态格局基本维持着天然状态;1959—2000年,地下水位持续下降,局部地段出现降落漏斗;2000—2008年,地下水位骤降,降落漏斗迅速扩张,地下水与地表水补排关系发生变异;2008年至今,部分区域地下水位逐渐上升。（2）研究区内山前地带地下水生态水位埋深为10~15?m,拒马河冲洪积扇群与漕河—瀑河冲洪积扇群为5~10?m,唐河—大沙河冲洪积扇群为3~5?m,冲积平原中定州—望都范围为3~5?m,保定市为10~15?m,其余均为5~10?m,冲湖积平原环淀区域小于3?m。（3）以确定的地下水生态水位为标准,初步估算研究区现状地下水位恢复至生态水位的需水量为57.14×108?m3。研究成果对恢复当地地下水生态环境格局有重要意义,对华北平原地下水生态水位的确定也具有借鉴意义。 相似文献
8.
A change for the worse in water quality in Lake Biwa has led to musty odor of tap water, freshwater red tide and other water blooms by sudden propagations of nuisance planktonic algae since 1970. Further, some endemic and commercially important species of fish and molluscs decreased drastically in the last 10–30 years. These events seemed to be closely related to drainage of many small lakes channeled to Lake Biwa as part of an agricultural policy after World War 11, and to senseless exploitation of the littoral zone in the 1970s and 1980s as a link in the Comprehensive Development Project of Lake Biwa. Simplification of its littoral zone has led to a deterioration in its ecosystem through physical destruction of spawning habitats and increase in eutrophication. 相似文献
9.
10.
根据三峡工程坝区水域实测数据,分析了水库蓄水以后大坝上、下游断面溶解氧浓度和溶解氧饱和度的变化特性,探讨了水位、流量因素对大坝下游水体溶解氧量的影响。结果表明,坝身孔口过流水体大量掺气后进入下游河道导致下游水体溶解氧浓度和饱和度显著增加,甚至达到超饱和状态。由于电站过流基本不改变水体溶解氧量,在电站和坝身孔口同时过流时,两种水体掺混后,下游溶解氧量主要受流量比的影响。此外,下游溶解氧量随流量的增加和下游水位的升高而增大。过坝总流量超过35 000 m3/s,下游水位超过68 m以及坝身孔口过流流量占总流量的绝大部分时,需特别重视溶解氧超饱和现象对水生生物可能造成的影响。 相似文献
11.
Field experiments were conducted to study the short-time response in growth and sediment properties of Zizania latifolia to four levels of water depth: 10, 50, 90, and 130 cm. The results showed that Z. latifolia was sensitive to high water depth stress in terms of the significantly decreased basal stem diameter, leaf width, root length, total biomass, and root to shoot ratio with increasing water depth. It was found suitable to grow in shallow water less than 50 cm in depth. The growth of Z. latifolia significantly increased sediment moisture content and porosity, while reduced wet bulk density in sediment and NH4–N concentration in interstitial water. Along the water depth gradient, the growth of Z. latifolia significantly impacted sediment wet bulk weight and loss on ignition, both NH4–N and PO4–P concentrations in interstitial water. However, no obvious regularities were observed in the sediment vertical profiles. NH4–N and PO4–P concentrations in interstitial water were much higher than in overlying water, indicating that they could diffuse from sediment to overlying water. NH4–N concentration was also higher in deep sediment. Growth properties of Z. latifolia (except for leaf length) are significantly correlated to wet bulk density, loss on ignition, NH4–N concentration in sediment and NH4–N, PO4–P concentrations in interstitial water. The results indicate that water depth less than 50 cm is favorable for the growth of Z. latifolia, where it can exert its ecological function effectively. This research suggests a possibility to promote the growth of Z. latifolia and exert its ecological function by rational water depth management. 相似文献
12.
灌区水资源合理配置是提高灌区水资源利用效率及保障粮食安全的重要途径,也是实现灌区水资源可持续利用的有效调控措施。从灌区水资源管理政策、水资源循环转化规律、水资源优化配置模型与方法和水文生态4个方面,对国内外该领域的研究现状进行了对比分析。研究发现,国内灌区水资源配置主要存在4个方面的问题:水资源合理配置与保护政策落实不到位、水资源的统一管理机制不健全、水资源优化配置模型实用性不强和水资源优化配置基础条件较为薄弱。建议加强灌区水资源的统一管理政策与机制、变化环境下水资源循环转化规律、水资源承载力基础理论与评价新方法、水文生态调控技术、水资源实时风险调度与智能化管理技术以及水资源优化配置耦合技术研究。 相似文献
13.
Akhtar Husain Siddiqi 《GeoJournal》1992,26(3):395-411
This study assesses the condition of the fishing industry in Pakistan. It briefly reviews the ecological environment of Pakistan's
fisheries and describes recent developments in technology and their impact on the catch. The factors contributing to growth
include government efforts, fleet expansion and development of export markets. This study also points out the difficulties
in arriving at a satisfactory management policy for the regulation of the industry. Development strategies seek rational,
efficient exploitation of marine resources for the broad goals of national development. Consequently, policy makers' fisheries
management concepts and techniques are generally less effective in addressing the need of the coastal communities. The conclusion
is that fisheries development effort need balanced resource management, serving as an instrument for regional development
while taking into account the traditional resource use rights of small-scale fishermen. 相似文献
14.
Whilst ecological modernisation theory emphasizes the potential for modern societies to recognize and respond to their environmental impacts by finding new ways of governing environment-economy relations, concepts of policy learning focus on the scope for new forms of environmental policy to be generated within and transferred between different contexts. Within this paper we explore the conceptual and practical linkages between the two areas of debate - a hitherto neglected area in the literature - and we set this discussion in the context of environmental policy-making in Hong Kong. We suggest that the practical relevance of the concepts of ecological modernisation and policy learning depends upon the presence of a reflexive society with rational, responsive institutions. While many theorists assume that such institutions exist, our analysis of policies for water and air quality management in Hong Kong highlights the need for theories to consider the embeddedness of existing institutions and the significance of the capacities for, and the barriers to, change more fully. We find that capacities for some forms of ecological modernisation and policy learning do exist in Hong Kong. However, we argue that the nature of these capacities often limits the potential for change to those local environmental problems that can be addressed through more technically and economically viable forms of policy intervention and that can be easily accommodated within existing political and economic structures. We also conclude that the capacities for ecological modernisation and policy learning that are needed if Hong Kong is to tackle the effects of the trans-boundary environmental problems that it is increasingly encountering have yet to emerge. 相似文献
15.
Macroinvertebrates are a major food source for fish species and macrophyte beds are hypothesized to harbor a rich community of these organisms. Macroinvertebrates inhabiting the water column in two macrophyte beds and an adjacent open area were sampled in a small embayment of the tidal freshwater Potomac River. One macrophyte bed consisted of an almost complete monoculture ofHydrilla verticillata, while the second community was a more diverse mixture of plant species. In samples with substantial amounts of submersed aquatic vegetation (SAV), macroinvertebrate density was two orders of magnitude higher than and substantially more taxa were found than at the open water site. Total macroinvertebrate abundance was significantly greater at theH. verticillata site than at the mixed site in July, but no significant difference was observed in August. Taxa richness did not vary between the two vegetated sites in July but was higher in the mixed bed in August. While the two vegetated sites shared similar taxa, they differed in their abundance. TheH. verticillata site harbored more hydrobiid snails, and the mixed site was characterized by more chironomids and hydroptilid caddisflies. Differences between July and August collections were even greater than between sites. Numbers of hydroptilid caddisflies, baetid mayflies, and coenagrionid damselflies were substantially higher in August, while oligochaetes, hydrobiids, and chironomids were reduced. Results support the hypothesis that water-column macroinvertebrates are greatly enhanced in the presence of macrophytes. The ecological significance of the less substantial differences in macroinvertebrates between macrophyte beds requires further study. 相似文献
16.
根据水文观测和引水与水电开发资料,分析了大通河流域水能水资源开发利用现状及其对河流水文过程与生态环境的影响.结果表明：由于区域用水和跨流域引水,使大通河中下游河道的水量减少,水环境容量减小,其中,青石嘴、天堂、连城(二)站3-11月平均流量分别减少0.6%~9.6%、0.5%~3.8%、1.7%~52.9%. 自1994年引大入秦工程建成跨流域引水后,连城(二)站年径流量开始减少,1994-2010年平均径流量比1977-1993年减少了5.7%;引大济湟工程建成通水后,加上引大入秦和引硫济金工程,引水总量将达到12.33×108 m3,占大通河多年平均径流量28.16×108 m3的43.8%,对河川径流的影响十分显著. 至2011年,大通河上已建成梯级电站34座,洪水期电站同时泄水会瞬间加大河道流量,枯水期蓄引水又使减水河段水量减少. 梯级水电站群无序蓄放水使洪水过程由天然的平稳状态转变为人工干预的剧烈变化状态,上下游洪峰不对应,对下游地区的防洪安全产生极大威胁. 过度的水能水资源开发,使大通河中下游部分自然河段出现淹没、断流,水生物和两岸的植物萎缩,水环境污染加重,对生态环境产生负面影响. 建议实行流域水资源统一管理,对梯级电站下泄水量统一调度,在减水河段预留必须的生态基流,确保河道内外生态用水;加强河道水位、流量、泥沙、水环境、水生物监测,为流域防汛、水资源管理、生态环境保护等提供决策依据. 相似文献
17.
The Zhangye basin is in the middle reaches of the Heihe River, northwestern China. Heavy abstraction of groundwater since
the 1970s in the area is for agricultural, industrial and drinking water supplies and has led to a substantial decline in
the potentiometric surface. A three-dimensional regional numerical groundwater flow model, calibrated under transient conditions,
has been developed and used to predict the drawdown for the period from 2000 to 2030 under two different groundwater management
scenarios. 相似文献
18.
《Journal of African Earth Sciences》2007,47(2):73-87
Several quartz vein sets with varying orientation, geometry and internal structure were recognized in the Atalla area. The veins were associated with the deformation phases affecting the area. En echelon and extensional veins are the main geometrical types. Syn-kinematic veins associated with the major northeast-over-southwest thrust faults were later boudinaged, folded and re-folded. En echelon veins, fibrous veins, and extensional veins are associated with the NNW–SSE faults. Other veins are associated with the NW–SE, N–S, NE–SW and E–W faults. Veins are concentrated at the intersection zones between faults. The internal structure of the veins comprises syntaxial, antitaxial, and composite types and reflects a change from a compressive stress regime to an extensional one. Chocolate-tablet structures and synchronous and co-genetic vein networks indicate later multi-directional extension of the area. Interaction between cracking and sealing of fractures is a common feature in the study area indicating that it was easy for the pore pressure to open pre-existing fractures instead of creating new ones. The reopening of pre-existing fractures rather than creating new ones is also indicated by the scattering of vein data around σ3. There is an alteration and change in characteristics of the wall rock due to increase in fluid flow rate. Fault-valving probably is also a cause of the complex geometry of some veins. 相似文献
19.
The island of Korčula, which has an area of 271.47 km2 is located along the north-eastern coast of the Adriatic Sea. Due to the Mediterranean climate, size and karst geology its
water resources are very scarce. This paper describes the natural features of the island (air temperature, precipitation,
geology, hydrogeology and groundwater) which are important for the water appearance and its distribution in time and space.
The water supply of the island has been managed in the following ways: through a pipeline from the mainland, by drawing groundwater
and by rain harvesting. Tourism causes high seasonal water needs which are barely met by the existing water supply system.
Therefore, present water resource management on the island must be improved. The paper also presents mathematical programming
scheme to get optimal costs and benefits of water exploitation on the island. Besides economic aspect, linear programming
is applied to social and ecological objectives, as well. This study suggests that island’s water management should be primarily
based on wisely using its proper water resources. 相似文献
20.
将交易成本分析引入沙漠化地区生态建设政策分析过程, 确定交易成本由搜寻信息成本、签订合约成本、建设及营运成本、监督对方是否违约成本、违约后寻求赔偿成本共5部分构成. 每个部分根据研究区域生态政策实施的关键节点进行指标分解, 设计政策交易成本分析的21个指标. 为了将不同生态政策之间的绩效进行对比, 构造了交易成本结构指数, 它由内生交易成本占总交易成本的比重、农户投入占生态建设项目生产成本的比重、交易成本占生态建设项目交易成本与生产成本之和的比重共3个指标构成. 根据在宁夏盐池县的调研数据, 测算退耕还林政策和天然林保护政策的交易成本分别为640.87元·hm-2·a-1和41.49元·hm-2·a-1, 交易成本结构指数值分别为0.1242和0.2292, 实施效果分别是很好和较好;"三北"防护林政策的交易成本为806.08元·hm-2·a-1, 交易成本结构指数值为0.4149, 实施效果一般;草地禁牧政策的交易成本为530.45元·hm-2·a-1, 交易成本结构指数值为0.8575, 实施效果很差. 生态政策的交易成本及其结构分析, 将为不同生态建设政策的比较和绩效评价提供一个新的角度, 具有重要意义. 相似文献