河道采砂管理问题及其研究进展

从河砂权属界定、采砂规划编制与许可选择、采砂交易方式探索、非法采砂行为应对,以及采砂管理信息化建设等方面对采砂管理研究进行梳理和综述.综合分析表明:所有权行使主体代表的不明确使得采砂管理责任主体缺位;采砂影响与采砂规划编制间内在作用机理的缺失制约着采砂规划方案决策的科学性;现有研究对不同采砂交易方式适用条件的认识不足;...     

长江口采砂方案评价指标体系初探——以东风西沙水库工程采砂方案为例

近年来,为改善投资环境,长江口沿江两岸堤内外吹填造地对河道砂石的需求量逐渐增大。大规模无序、盲目的采砂活动已引起局部河势的不利变化,危及长江口防洪及通航安全。为规范长江口采砂行为,维护长江河口的健康,迫切需要建立一套科学的评价指标体系,为评价采砂活动提供方法。结合近年来编制采砂可行性论证报告的实际工作经验,对长江口采砂方案评价指标体系进行了初步探索,提出了评价指标的评价方法与评价标准,供业内同行及采砂管理部门参考。     

A review of regulation mechanisms of metazoan plankton in riverine ecosystems: aquatic habitat versus biota

This review summarizes the key factors of a series of articles about animal plankton in rivers, a topic that remains poorly investigated. Running water, in which sampling processes are variable and often difficult, acts as a constraint as well as a resource for plankton. Assessment of the potamoplankton reveals that good swimmers of the true plankton are mixed with numerous poor swimmers among littoral and epibenthic forms. Small taxa dominate communities in most of rivers all over the world and, in comparison with crustaceans; the successful development of rotifers rests on their shorter development times. According to hydraulic and geomorphological features, the diversity of the habitats and the ability of individuals to avoid washout was examined, decrease in flow creating standing zones favourable to zooplankton development. Many species can find suitable conditions for the development of dense populations in stream habitats and examples of taxa‐specific response, regardless of the habitat structure, are observed. While the challenge for riverine plankton remains ‘eat to be fruitful and multiply’, their activities have been poorly investigated in turbulent conditions, those able to continue growing in a current of 20 cm s^?1, such as brachionid species, being usually dominant in rivers. Examination of the distribution of plankton populations, in the Middle Loire and in other rivers, showed that the flow regime, which plays a central role in organizing river habitats, explains the presence/absence of these fast‐growing organisms. While reservoirs are major sources of crustaceans, lateral exchanges as well as downstream transport are important in determining the plankton. These ecosystems are primarily governed by abiotic factors, biological control taking place after physical control has happened. Because animals arrive by chance in any habitat during dispersion, zooplankton in rivers remains primarily governed by unpredictable physical processes and depends on the age of the water and the availability of habitats. In this way, the hydro‐dynamics of river habitats need to be more documented with regard to their key role in the planktonic life. Preservation of the lentic areas remaining at the heart of the matter, the contrasting ecology of the rotifers should be a reliable tool with which to estimate the changes in habitats diversity of main channels, particularly during droughts, while crustacean's diversity would be more representative of flood plain annexes, particularly during flood events. Copyright © 2006 John Wiley & Sons, Ltd.     

河道采砂交易合同计价模型研究

河道采砂交易主要有采砂权交易和采砂作业交易两种基本模式。针对河道采砂交易中超采现象严重,危及堤防工程安全的实际,分析了河道采砂权交易计量的特点,提出了以超采率为控制参数,激励约束相结合的采砂权交易合同计价模型。而且,分析了采砂作业交易中作业成本的特点,将作业成本分为固定成本和可变成本,提出了分段计价采砂作业交易合同计价模型。通过合同计价方式创新,借助经济手段,可有效地压缩超采的利润空间,减弱超采的驱动力。     

江西省河道采砂生态保护践行分析与探索

河砂既有矿产资源属性,又具有生态环境属性,河道采砂对河流环境及周边环境均存在一定影响,加强生态保护是河道采砂管理在水生态文明建设新时期应当遵循的总原则之一。本文立足江西省河道采砂生态保护创新,从河道采砂采区规划、许可、监管三大环节提出践行落实生态保护的具体措施,对生态保护控制与管理工作的发展作出展望。     

河湖采砂协同感知与智慧管控技术研究及应用

针对传统河湖采砂管理存在的人力投入大、无序采砂行为“看不到”“逮不着”、执法难、智能化程度低等难点,面向河湖采砂管理中的船只管理、行为识别、采砂量管理、网络传输等需求,开展了采砂船行为识别、采砂量实时监测、复杂水域网络传输、智慧管控等采砂管理关键技术研究,并研发了河湖采砂信息管理平台,实现了采砂过程智能化管控。成果在江西省鄱阳湖区和赣江部分河段得到较好应用,成效显著,为河湖采砂管理提供了强有力的技术支撑。     

长江镇江段河道采砂的影响及其控制利用的试验研究

运用微尺度模型和基于普通相机的近景摄影测量三维图像解析技术针对河道采砂对长江镇江段河床演变的影响进行了试验研究。分析了镇江段河床演变的趋势，指出在征润洲北滩和五峰山附近科学台理地采砂有利于镇江段河床稳定。考虑到镇江段较长时期的河势稳定除改善征润洲，焦山一带态势还应遏制和畅洲南北汊逆转的趋势，必须采用包括河道采砂在内的综合治理措施，结果还表明微尺度模型可以用于河工动床模型研究，特别适用于多方案的定性分析与比较，近景摄影测量三维图像解析技术在数字化试验研究中可有良好的应用前景。     

长江河道采砂管理实践与展望

"十五"期间,国务院颁布实施了《长江河道采砂管理条例》,长江河道采砂管理进入了法制化轨道,水行政主管部门肩负起长江河道采砂管理的重任.几年来,通过水行政主管部门的艰苦努力,非法采砂活动得到了有效遏制,长江河道采砂由无序逐步向依法、科学、有序转变,长江河道采砂管理工作取得了显著成效.长江河道采砂管理在新的形势下又出现一些新的问题,针对出现的新问题,提出了解决的措施.对"十一五"期间长江河道采砂管理进行展望.     

基于GPRS的采砂船舶监控系统设计

为了有效监控和规范采砂船的作业行为,基于GPRS技术,运用北斗导航定位技术设计了采砂船舶位置跟踪和航行线路的实时监控系统。系统可根据采砂船的位置和时间来判断采砂船采砂作业是否合法。系统设备的电源采用自供电,运用清洁的太阳能为设备供电,而GIS服务器接收到北斗卫星信号后,结合AIS电子海图,可实时在电子海图上显示采砂船的位置并对是否违规进行分析。由于主控芯片使用了Atmegal28单片机芯片,设计的采砂船监控系统具有成本低、体积小、能耗低、绿色无污染和系统性能可靠等特点。     

坚持依法行政原则 提高采砂监管水平

长江河道采砂管理工作具有重要性、长期性、艰巨性、复杂性、敏感性和高风险性等六大特征,采砂管理工作是水行政主管部门最难做、最富有挑战性的工作之一。相关主管部门必须始终坚持依法行政,始终坚持依法监管。结合新一轮机构改革后长江流域河道采砂管理的职能定位,就流域有关采砂管理的法律问题进行探讨,阐明坚持依法行政、依法监管原则对长江流域河道采砂管理工作的极端重要性。     

长江中下游干流河道采砂规划研究与探索

长江中下游干流河道内的砂石是较好的建筑和填筑材料.为防止采砂对长江河势稳定、防洪安全、通航安全、水生态环境保护以及沿江工农业设施的正常运行带来较大的不利影响,长江河道采砂必须进行统一规划.长江中下游河道采砂规划研究工作自20世纪90年代初逐步展开,到国务院颁布《长江河道采砂管理条例》后,开始按水利部的部署对长江中下游河道进行统一规划,规划研究与探索工作取得了丰硕的成果.较系统地阐述了长江中下游干流河道采砂规划研究过程、取得的主要成果以及成效,提出了进一步做好长江中下游干流河道采砂规划工作的建议.     

关于长江中下游干流河道采砂管理决策的思考

运用公共管理决策的理论分析了决策在长江中下游干流河道采砂管理中所发挥的作用,并就决策中领导因素、决策程序、利益驱动和风俗习惯等方面因素所起到的影响作了进一步阐述.长江中下游干流河道采砂管理的发展历程,也就是国家及各级政府有关河道采砂问题决策不断更新、调整的一个过程.长江中下游干流河道采砂管理的好坏,关键就在于国家的有关决策是否科学、合理,各级人民政府的政策择取是否正确.     

鄱阳湖入江水道总磷时空分布规律及采砂影响简析

为了探讨鄱阳湖入江水道的总磷时空分布规律,区分水文自然节律与采砂影响的主次关系,结合区间纳污情况,对老爷庙、星子及蛤蟆石断面的总磷监测数据进行了时空变化的数理统计分析.结果表明:由于入湖水量差异导致水体自净能力与纳污能力的变化,鄱阳湖入江水道主要断面的总磷指标存在"丰水期优于枯水期"的周期性波动规律;老爷庙-星子段总磷浓度总体呈现优化趋势;星子-蛤蟆石段则呈劣化趋势;鄱阳湖采砂相关作业对断面水质存在一定的影响,但其本质是底泥扰动带来的内源性污染迁移,其影响较入湖排污带来的外源性污染要小.研究结果有助于更加理性地分析采砂对水质的影响.     

浦东机场跑道工程江砂开采及对河道的影响

为满足浦东国际机场工程建设需要,从有利于河势和航运等角度出发,选择了长江口南槽江亚南沙南侧、九段沙保护区外侧的砂源区作为工程采砂区,并拟定采砂方案。采用delft 3D模型分析采砂前后工程区附近的流场变化。并从河势、防洪、水环境、通航、航道和生态等方面分析了采砂对长江口南槽河段的综合影响,论证采砂的可行性。通过分析得出采砂对长江口河道基本无影响。     

Experimental evidence for density‐dependent effects and the importance of algal production in determining population growth rates of riverine zooplankton

Food limitation effects on life history traits of lake zooplankton have been well documented but few studies have examined linkages between population growth rates and food resources in riverine environments. In rivers, allochthonous inputs of particulate organic matter may mitigate food limitation effects allowing density‐independent mechanisms associated with washout (discharge) and feeding interference (turbidity) to assume greater importance. We experimentally manipulated densities of commonly occurring riverine zooplankton (Bosmina longirostris and cyclopoid copepods) within 2000 l mesocosms containing ambient or algal‐enriched food resources. The experiment was repeated through time (July, August, September) to represent the range of zooplankton densities and food resource levels observed in the Ohio River during warm‐water, low‐flow conditions. High growth rates and low sensitivity to density‐dependent effects were observed during July when particulate organic carbon (POC) and chlorophyll concentrations were highest. Lower growth rates and stronger response to density‐dependent effects were observed during August and September experiments when POC and chlorophyll concentrations were lower. Direct manipulations of algal abundance resulted in higher growth rates when gains in chlorophyll were accompanied by increases in the edible size fraction (September experiment). Algal C concentrations were found to be a significant predictor of variation in population growth rates for Bosmina but not cyclopoids. Algal C concentrations in the Ohio River rarely fell below experimentally derived minimum food thresholds but were often below saturation thresholds suggesting that population growth rates were constrained by autochthonous food resources despite the prevalence of allochthonous carbon. Copyright © 2005 John Wiley & Sons, Ltd.     

Large freshwater lakes in arid Australia: A review of their limnology and threats to their future

Large freshwater lakes in Australia’s arid zone are episodic due to highly variable inflows from allogenic rivers. A few receive enough inflow almost yearly to be permanent, despite large losses from high evaporation. Biodiversity is high, with most taxonomic groups represented, and is largely endemic at the continental scale. There is almost no regional endemism, which is at variance with other major aquatic habitat types in Australia. Abundance fluctuates greatly, with invertebrates and fish booming and busting with floodwater input, but birds generally reach greatest numbers later in the cycle as they gather on the more persistent waters. Invertebrate assemblages are influenced by the degree of lake permanence, turbidity and salinity, providing a temporally variable mosiac of environments throughout a lake system and between systems and with time. Unlike other groups, fish are not speciose, but are important predators in most systems with breeding coinciding with flooding. This favours native species against exotics in the Coongie Lakes but, in the Paroo, exotics are common in permanent waters. Waterbirds are the very obvious components in these variable systems, using their resources for feeding and breeding. Most are extremely nomadic to take advantage of the variable habitat. Two of the most important lake systems, the Coongie Lakes on Cooper Creek and the Paroo lakes in the northwestern Murray Darling catchment, are threatened by water abstraction upstream for irrigation, so that important habitat may be lost. In addition, the lakes will become less variable and, so, possibly compromise their character with cascading effects through the ecosystem. Some smaller lakes are adversely impacted by accelerated sedimentation.     

A review of the effects of pollution and water scarcity on the stream biota of an intermittent Mediterranean basin

This review presents the main results of a 10‐year research study conducted in a Mediterranean intermittent basin (Evrotas River). By assembling the main outcomes of past and ongoing research projects, this study provides an overview of multiple stressor effects, with emphasis on water scarcity, focusing on hydro‐biogeochemical processes, as well as on spatial and temporal variations in benthic macroinvertebrates and fish fauna. The major impact in the basin has been the over‐exploitation of surface and groundwater resources, which, in combination with droughts, has resulted in the recurrent artificial desiccation of large parts of the hydrological network. The response to intermittency of the macroinvertebrate fauna is characterized by high resilience through various drought‐resistant evolutionary mechanisms, with assemblages recovering successfully after recurrent droughts. However, when pollution is evident in combination with drought, effects on benthic species richness, abundance, and assemblage structure can be severe. Similarly, pollution and water stress may result in massive fish mortalities due to hypoxic conditions, with fish populations requiring long periods to recover. However, the fish fauna appears to be relatively resilient to drought‐driven reach‐scale desiccation, and ultimately recovers, provided that aquatic refugia are available to supply colonists and that there are no physical barriers impeding recolonisation. Appropriate conservation measures are urgently required to address the effects of recurrent bouts of water stress, as well as of other stressors on the freshwater communities of the Evrotas River, both at the level of water management and of water policy and at the local and the national level.     

Impacts of climate change on groundwater in the Great Lakes Basin: A review

Climate change has the potential to alter the physical and chemical properties of water in the Great Lakes Basin, in turn impacting ecological function. This study synthesizes existing research associated with the potential effects of a changing climate on the quality and quantity of groundwater in the Great Lakes Basin. It includes analyses of impacts on (1) recharge, (2) groundwater storage, (3) discharge and groundwater-surface water (GW-SW) interactions, (4) exacerbating future urban development impacts on groundwater, (5) groundwater quality, and (6) ecohydrology.Large spatial and temporal (i.e., seasonal) variability in groundwater response to climate change between regions is anticipated. Most studies combine field observations with modelling, but many have focused only on small/medium basins. At these small scales, groundwater systems are generally projected to be fairly resilient to climate change impacts. However, modelling studies of larger basins (e.g., Grand River, Saginaw Bay, Maumee River) predict an increase in groundwater storage. Uncertainty in model simulations, particularly from climate models that are used to force hydrological models, is a major challenge. There have been too few studies to date that investigate the interplay of climate change and groundwater quality in the Great Lakes Basin to draw conclusions about future groundwater quality and ecohydrology.A summary of methods, models, and technology is provided. Model uncertainty has become an increasingly important topic and is also discussed. The study concludes with a synthesis of the main science needs to understand groundwater impacts in order to adapt to a changing climate in the Great Lakes Basin.     

滴灌用砂过滤器的过滤与反冲洗性能试验研究

通过试验和分析，本文对节水灌溉工程中使用的砂过滤器的过滤与反冲洗性能进行了研究，提出了新的过滤阻力与雷诺数的关系式，给出了计算初始水头损失计算公式，分析了过滤与堵塞规律，提出了最佳反冲洗强度和膨胀率，并对反冲洗效果进行了实际验证，为正确设计和使用这类过滤器提供了理论依据。