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1.
20世纪90年代以来,河流生态环境需水成为生态水文学研究的重要内容。阐述了基于国际上新兴发展的生态水文学理论的生态环境需水量的概念和内涵。并以毗河为例,用能反映时间尺度的河流流量来表达生态环境需水量,而不是传统意义上的水量。为了与水资源配置的时间单元协调起来,对3个代表年〖WTBX〗P〖WTBZ〗=50%(1968年),〖WTBX〗P〖WTBZ〗=75%(1986年),〖WTBX〗P〖WTBZ〗=90%(1987年)分别进行生态环境需水量的计算。根据毗河的自然条件,利用Montana法计算了河道维护水生生境最小需水量和最适宜需水量;蒸发需水量由水面宽度、河道两断面间平均长度、河道蒸发深度三者确定;结合河道功能区划和水质目标,计算了污染物稀释需水量。最终确定毗河下游河道的最小生态环境需水量为20.64 m3/s,最适宜生态环境需水量为25.84 m3/s。  相似文献   

2.
In the first multipurpose river valley planning of India, the vast resources of Damodar River Basin (DRB) (eastern India) are not only to be envisioned in their entirety but also to be developed in a unified manner where the water, land, and people are simultaneously bounded in a seamless web. Four large dams (Konar, Tilaiya, Maithon, and Panchet), Durgapur barrage, and Tenughat reservoir are built to tamp the flood-prone Damodar River using water resource in an integrated method. The functionality of Damodar fluvial system is controlled by dams, barrage, weirs, sluices, embankments, and canals, maintaining a dynamic equilibrium between fluvial processes and anthropogenic processes. Carrying more than 50 years of legacy, the existing drainage and flood control system of Damodar Valley Corporation has aggravated a number of hydrogeomorphic problems especially in lower DRB, viz. siltation of river bed and reservoirs, uncontrolled monsoonal stream flow, declining carrying capacity of lower course, drainage congestion, low-magnitude annual floods, channel shifting, de-functioned canals, decay of paleochannels, decline of ground water level, and less replenishing of soils with fresh silts. The present paper is mainly tried to investigate the pre-dam and post-dam hydrogeomorphic variability in relation to flood risk and drawbacks of Damodar Valley Multipurpose Project. Specifically, the annual peak flow of Damodar shifts from August to September due to dam construction and reservoir storage. Applying the annual flood series of log Pearson type III distribution, we have estimated post-dam 5-year peak discharge of above 5,300 m3 s?1 and 100-year flood of above 11,000 m3 s?1. Due to siltation, the bankfull discharges of sample segments are gradually declined up to 4,011 m3 s?1, 2,366 m3 s?1, and 1,542 m3 s?1, respectively, having recurrence interval of 1.18–3.18 years only. With the regulation of monsoon flow, the standard sinuosity index is gradually increased downstream, having high dominance of hydraulic factors in respect of topographic factors. The upstream section of study area (Rhondia to Paikpara) now shows the dominance of aggradational landforms, braiding, avulsion, high width–depth ratio, breaching of right bank, and valley widening, but downstream of Barsul the phenomena of bank erosion, confined sinuosity, low width–depth ratio, and narrowness are more pronounced.  相似文献   

3.
In view of no generally accepted ecological compensation standards and methods at present,this paper discusses the introduction of the negotiation system to the process of ecological compensation for water source areas.That is,the government in water source areas and the downstream regions of river basins should confirm their respective rights and obligations and then establish their compensation standards through negotiations according to the different purposes of water use.The amount of compensation should be determined in the comprehensive consideration of the quality,quantity and compensation price of water.Through open and fair negotiations,an institutional arrangement will be set up,which can make the water source areas and the downstream regions of river basins fully express their true preferences and their independent choices on the ecological environment.  相似文献   

4.
The use of cuprous fungicides in cocoa production in the southern part of the state of Bahia (Brazil) for decades has caused an accumulation of copper in various components of the cocoa plantations, and a contamination of regional freshwater ecosystems is suspected. Urban and industrial sources are supposed to contribute to water pollution and eutrophication of the Rio Cachoeira, the main river in this region. In order to study the metal contamination and nutritional status of this freshwater ecosystem, samples of the aquatic macrophytes Eichhornia crassipes and Pistia stratiotes were collected at seven sites along the river course. The samples were analysed for their copper, aluminium, chromium, nitrogen and phosphorus concentrations. The levels of heavy metals increased in the downstream direction, particularly in the roots of water hyacinth. A dramatic increase of nitrogen and phosphorus concentrations in water as well as in plant tissues was found in samples collected downstream from the city of Itabuna. Metal input and eutrophication were attributed to agricultural, industrial and urban sources in the region. Biomonitoring of the water quality using aquatic macrophytes as accumulative indicator plants is recommended in addition to chemical water analyses.  相似文献   

5.
着生藻类在水质监测与水生态健康评价中发挥着重要作用。以江西最大的河流赣江为研究对象,对赣江丰水期着生藻类群落结构及其与环境因子的关系进行研究。选取53个点位对赣江全流域进行着生藻类群落结构的调查研究,共鉴定着生藻3门42属175种,其中硅藻门有23属151种,绿藻门有9属12种,蓝藻门有10属12种。硅藻门舟形藻属为丰水期赣江流域着生藻类优势属,该属生物密度百分比为14.080%。下游着生藻类以硅藻门桥弯藻属和舟形藻属为优势属,该属生物密度百分比分别为13.088%和12.935%;中游着生藻类以硅藻门桥弯藻属为优势属,该属生物密度百分比为12.849%;上游着生藻类以硅藻门异极藻属为优势属,该属生物密度百分比达10.150%。通过蒙特卡罗显著性检验发现,赣江流域下游总氮、溶氧、叶绿素a和电导率对着生藻类有显著影响,中游主要海拔、流速、河宽和总磷对着生藻类有显著影响,上游总氮、河宽、浊度和流速对着生藻类有显著影响。将其与着生藻类群落结构进行冗余分析(RDA),结果发现影响下游着生藻类群落结构的主要水环境因子为叶绿素a和电导率,影响中游、上游着生藻类群落结构的主导水环境因子分别是海拔和总氮。可见赣江流域丰水期下游和上游的着生藻类群落可在一定程度上反映水质状况,中游着生藻类群落结构主要反映的是流域地貌因子。  相似文献   

6.
按照流域尺度从小到大,分别选择新安江流域、珠江流域和长江流域作为研究对象,通过实证分析发现上下游水环境库兹涅茨曲线遵从一定的演递规律,即上游地区往往会重复下游地区的曲线过程,但其发展阶段落后于下游地区。上下游的发展差异越大,这种规律表现得越明显。产生这一规律的主要原因是我国多数流域下游地区的经济发展水平一般高于上游地区,下游比上游更早地到达了环境库兹涅茨曲线的峰值,并具有了更强的环境保护能力。这一规律有助于深化对上游水资源保护的重要性的认识。国家和下游地区需要加强对上游欠缺的生态环境保护能力的支持和援助,降低上游水环境库兹涅茨曲线的峰值和曲率,从长远意义上减轻上游发展过程中对全流域生态环境产生的不利影响和生态保护代价。  相似文献   

7.
采用Morlet小波分解重构和频谱分析等方法,对宜昌、枝城、沙市、监利和城陵矶1997~2014年水位和流量及三峡水库2003~2014年入库、出库流量和库水位数据进行了统计分析,探究了各水文站在三峡建坝前后水情的变化特征及原因。结果表明:各观测站的水位和流量沿程递减,水位的年内波动处同一水平,研究河段内上游河段流量年内和年际变化比下游河段剧烈;各水文站水位和流量变化的显著周期为6.05、11.78、21.2、30.29和53个月,各水文站水位1 a周期变化幅度均在2 m以上,其他周期上的变化幅度为0.08~0.82 m;三峡水库蓄水活动对下游水文站水位和流量等水情的影响有限,主要反映在对水情趋势项的影响上,三峡大坝蓄水后,各水文站水位和流量受到一定程度影响,呈波动性递减变化。  相似文献   

8.
The effects of changing climatic and socioeconomic conditions on the water quality of the Elbe River were investigated using the deterministic model QSim. Since the impact of global change on river water quality marks the endpoint of various processes in the catchment and in the atmosphere, this study was performed within a network of interacting models that determined input parameters for water quality simulations. The development of phytoplankton and nutrient concentrations under conditions of global change was modeled along a 700 km stretch of the river. The simulations revealed a strong, scale-dependent effect of climate change on phytoplankton biomass, leading to a longitudinal shift of the dominating processes (primary productivity vs. respiration) along the river continuum. Under reduced flow, combined with increasing temperature and global radiation, phytoplankton biomass increased and phytoplankton maxima shifted in upstream direction, followed by higher system respiration rates in the adjacent downstream sections. In contrast, higher flow shifted the phytoplankton maximum toward the downstream sections. Even a drastic reduction of phosphorus inputs from anthropogenic sources had only limited influence on algal biomass, due to the ability of algal cells to store phosphorus. A strong reduction in P-inputs especially in the headwaters would be necessary to counterbalance the possible climate-induced effects on algal biomass.  相似文献   

9.
Studies on the Komarovka River, flowing in the zone of mixed conifer-broadleaf forests in the southwestern Sikhote-Alin Mountains (Primorye, Russia), have shown that the formation of river flow and multispecific phytobenthos communities takes place mainly within 60–70 km2 of its catchment area. The summer-autumn runoff rate and taxonomic composition of algae in this river segment are closely correlated with the catchment area. The relative water content of the river decreases downstream because of decrease in the number of tributaries, while changes in the taxonomic diversity of algae depend on river flow velocity and water temperature.  相似文献   

10.
赣江是鄱阳湖流域最大水系,赣江水沙变化对鄱阳湖入湖径流、泥沙等水文特征有重要影响。目前对赣江水沙研究主要集中在下游外洲站河段,不足以反映全流域水沙变化规律。选取赣江上游4站、吉安和外洲水文站分别代表上、中、下游河段,基于近60 a的实测流量、悬移质泥沙资料,采用水文学和数理统计相结合的方法,分析赣江水沙年际变化特征以及可能影响因素,以期为流域水沙资源管理提供参考。结果表明:(1)赣江径流年际变化大,1970s、1990s水量较丰,其它年代径流偏少,年径流序列无显著变化趋势和突变点;(2)输沙量年际变化剧烈,呈显著降低趋势,上游4站、吉安站、外洲站输沙序列突变点分别为2002年、1995年、1995年,突变后年输沙量较突变前减少52%、71%、67%;(3)赣江上游水土保持建设是上游4站输沙量减小的主要原因;1993年后万安水库拦沙是吉安、外洲站输沙量显著减少的主要原因,水土保持、河道采砂也是引起吉安、外洲站输沙量减少的直接因素。(4)水土保持减沙的作用是缓慢和滞后的,而万安水库对下游河道的减沙作用是迅速而显著的。可见,赣江入鄱阳湖的年径流无明显减少趋势,入湖输沙量显著减少,有利于减少鄱阳湖的泥沙淤积、促进湖泊生态的良性发展。  相似文献   

11.
We evaluated the health condition of a temperate river during June-November 1999 through applications of the index of biological integrity (IBI) using fish assemblages and qualitative habitat evaluation index (QHEI) as well as chemical analyses. Overall IBI values ranged from 13 to 37 and averaged 23 (n = 25, standard error = 1.16), indicating a "poor" or "very poor" condition according to the criteria of modified Karr [Fisheries 6 (1981) 21]. The values of mean IBI declined at a rate of 0.22 km(-1) (R2 = 0.91, p < 0.05) along the longitudinal distance from the headwaters to the downstream sites. Reduced IBI values at downstream sites reflected low forest cover, high population density and high nutrient enrichments. Ecotoxicity tests using the river water also showed that toxic impacts were evident in the downriver sites. These factors resulted in decreases of riffle benthic species and insectivores and increases of tolerant species, anormalies and exotic species in the river. Spatial pattern in IBI agreed with QHEI values, which showed a linear relation (R2 = 0.998, p < 0.001) with species richness. Field measurements of conductivity and pH, an indicators for variation of conservative ions, showed that the river water was diluted by 40% fold by summer monsoon rain and surface run-off from the watershed, resulting in a physical and chemical instability during the monsoon. For these reasons, average IBI values during the monsoon and postmonsoon decreased >20% compared to the premonsoon, indicating that IBI values were also affected by flow regime. Based on the overall physico-chemical data and IBI values, the river health is rapidly degrading due to the combined effect of chemical contaminations and habitat modifications.  相似文献   

12.
Major modifications regulating the Tigris River, originated in the 1940s and continuing to the present, have resulted in changes in salinity in the system over time and in different portions of the river course. The increase in salinity is due to decreases in stream discharge due to dams, water management structures such as the Lake Tharthar system, irrigation return flow, and soluble minerals in the basin. This research documents the increase and evaluates the causes of the salinity increase of the river from predevelopment to present using published and previously unavailable data. The predevelopment salinity was under 600 ppm, since 1984 has exceeded the 1000 ppm threshold recommended for drinking water downstream of Amara. A minimum instream flow for the river is calculated at Baghdad and Kut at 185 cubic meters per second (cms), approximately 15% of the mean historical flow of the river, but above the lowest minimum flow recorded at 140 cms. Recommended salinity management options discussed include (1) eliminating Lake Tharthar as a water storage facility, (2) managing saline inflows from tributaries, and (3) employing a minimum instream flow for the river.  相似文献   

13.
绿水资源表示水循环通过降水渗透入土壤非饱和层并由植物蒸腾或土壤蒸发返回大气层的水汽,是农业作物生产的重要基础,但是通常被传统流域水资源管理所忽视。基于流域水量平衡和蓝水绿水综合思维,将绿水资源纳入流域水资源管理体系。在绿水信贷理念和博弈建模分析框架下,结合SWAT分布式水文模型、多目标优化及情景比较分析,利用绿水管理措施合理优化配置流域蓝水绿水资源,采用绿水生态补偿协调处理上下游利益冲突的博弈问题,探索性地提出了流域绿水管理博弈框架。该框架通过博弈建模可以识别分析流域绿水管理问题的博弈空间、博弈结构和纳什均衡等博弈特征;通过合作博弈约束条件改进的多目标优化,可以计算流域绿水管理情景的绿水补偿标准和帕累托最优收益。将建立的绿水管理博弈框架应用于涟水流域实例研究,NSE、R2、PBIAS、p-factor与r-factor等模拟效果评价和不确定性分析结果表明,涟水流域SWAT分布式水文模型的蓝水绿水模拟均达到可信程度。上下游收益变化、绿水补偿标准与帕累托最优解集等博弈分析结果显示,涟水流域整体社会经济与生态环境收益明显改善,其帕累托最优收益平均增长2.72亿元/a,年均绿水补偿标准折合1.94、1 253.7元/hm2。实例分析表明提出的绿水管理博弈框架在涟水流域具有较好的适用性和可行性。因此,该方法可以为流域蓝水绿水管理试点研究及其绿水补偿标准核定提供相关理论依据和技术参考,具有一定程度的的应用价值和现实意义。  相似文献   

14.
乌东德水库为季调节水库,采用宽度平均的立面二维水温数学模型对水库水温结构进行预测,结果表明:乌东德水库水温结构呈季节性分层特征,电站运行对下游水温过程有一定程度的春季低温水和冬季高温水影响。如果采用单层取水方案,在2~8月的下泄水温低于坝址现状水温,最大降幅为2.0℃,下泄低温水将对坝下鱼类产卵繁殖产生不利影响。乌东德水电站拟采取分层取水的措施,对低温水较为敏感的鱼类产卵期3~6月采用叠梁门取水。相比于单层取水,叠梁门方案对低温水的改善效果较明显,下泄水温提高了0.8~1.1℃,能一定程度地减缓升温期水温延迟效应。  相似文献   

15.
Health risks from large-scale water pollution: trends in Central Asia   总被引:3,自引:0,他引:3  
Limited data on the pollution status of spatially extensive water systems constrain health-risk assessments at basin-scales. Using a recipient measurement approach in a terminal water body, we show that agricultural and industrial pollutants in groundwater-surface water systems of the Aral Sea Drainage Basin (covering the main part of Central Asia) yield cumulative health hazards above guideline values in downstream surface waters, due to high concentrations of copper, arsenic, nitrite, and to certain extent dichlorodiphenyltrichloroethane (DDT). Considering these high-impact contaminants, we furthermore perform trend analyses of their upstream spatial-temporal distribution, investigating dominant large-scale spreading mechanisms. The ratio between parent DDT and its degradation products showed that discharges into or depositions onto surface waters are likely to be recent or ongoing. In river water, copper concentrations peak during the spring season, after thawing and snow melt. High spatial variability of arsenic concentrations in river water could reflect its local presence in the top soil of nearby agricultural fields. Overall, groundwaters were associated with much higher health risks than surface waters. Health risks can therefore increase considerably, if the downstream population must switch to groundwater-based drinking water supplies during surface water shortage. Arid regions are generally vulnerable to this problem due to ongoing irrigation expansion and climate changes.  相似文献   

16.
A reconnaissance study has been made on the distribution of 238U, 234U, 232Th and 230Th in soils, water, suspended particulate matter (SPM) and bottom sediments in the Kali river basin around Kaiga, its estuarine region and the adjacent Arabian Sea to obtain the baseline data of U-Th series nuclides in view of the commissioning of nuclear power reactors at Kaiga, near Karwar, on the southwest coast of India. Drainage basin soils developed over greywackes (the dominant litho-unit upstream) are lower in 238U/Al and 232Th/Al ratios by factors of 3-5 in comparison with those developed over tonalitic gneisses (the dominant litho-unit downstream). The dominance of the former type of soils is reflected in the composition of river-bottom sediments derived from the upstream drainage basin during the monsoon. The 232Th in bottom sediments tends to increase towards the estuarine and coastal areas, presumably due to deposition of heavy minerals and onshore transport of coastal sediments into the estuary. The dissolved U in the Kali river is low (0.001-0.02 microg/l) when compared to the major Indian rivers as the Kali river flows through U-poor greywackes. Thus, the input of dissolved U to the Kali estuary is dominated by sea water. Although there is some evidence for the removal of dissolved U at low salinity during estuarine mixing, its behaviour is conservative in the lower estuary (at higher salinities). The removal rate of dissolved U from the Kali river basin is similar to that reported from other tropical river basins. The U flux from all the west-flowing rivers of Peninsular India is estimated at 26.3 x 10(6) g/yr to the Arabian Sea which is about 2% of the flux from the Himalayan rivers to the Bay of Bengal.  相似文献   

17.
葛洲坝下游近坝区水域鱼类资源声学调查与评估   总被引:2,自引:0,他引:2  
于2013年4月及6月,针对DIDSON的特点设计了携带声呐的船舶走航式及定点式两种方法,对葛洲坝下游近坝区水域(大江、三江至下游镇江阁处江段)进行水声学调查,观察鱼类资源的时空分布特点。观测数据经去噪处理,获得鱼类资源结果。结果表明:葛洲坝下游近坝区鱼类资源分布呈明显的空间差异,大江水域鱼类密度显著高于三江水域,且近坝区高于下游江段,最大值为6924 ind./1 000 m3,位于大江电站下游约1 km处,最小值为153 ind./1 000 m3,位于宜化大楼江段。鱼类资源在时间上没有显著的统计学差异,6月份鱼类活动昼夜差别比4月份更明显,主要集中在上层水域,傍晚至凌晨鱼类活动较少。进一步分析发现,船闸的运行方式、水体中食物可获取程度、各鱼类种群生活习性差异等,均对鱼类资源时空分布产生影响。此外,开展适逢葛洲坝禁渔期,禁渔措施维持了近坝区水域春、夏季鱼类资源量的稳定性,是保护鱼类资源的有效而直接的方法  相似文献   

18.
Drying of an inland river’s terminal lake in arid regions is an important signal of environmental degradation in downstream regions. A long-term, high-resolution understanding of the lake’s retreat and expansion and the driving mechanisms will inform future adaptive water management strategies, ecosystem restoration, and government decision-making in the context of a growing water scarcity in the inland river basin. The shrubs that grow along the shore of a lake often provide evidence of lake retreat or expansion. The chronological results showed that the earliest germination dates of the lakeshore shrubs, tamarisk, were in 1901, 1943, 1966, 2009, and 1990 from the higher terrace to the lower terrace of East Juyan Lake, a terminal lake of China’s Heihe River. Coupled with river and lake hydrological data, six obvious lake’s fluctuations were identified: shrinkage from 1900 to 1940s and during the early 1990s, expansion and retreat in the late 1950s and early 1970s, continued expansion from 2002 to 2008, and stabilization at a water area of around 40 km2 from 2009 to the present. The water elevation in the 1900s was below 905 m a.s.l., resulting in a water area <80 km2, but decreased to 40 km2 after 1960 and dried up completely by the 1990s. By analysing climatic and hydrological records since 1950, tree-ring climate proxy data, river runoff outside the observation period, and water resource consumption in the middle and lower reaches of the Heihe River, we found that the periodic expansion and retreat of East Juyan Lake was influenced by both climate change and human activities, but especially by human activities. The lake’s recent recovery and stability was achieved by government policy designed to provide environmental flows to the lake.  相似文献   

19.
The integration of water quality monitoring variables is essential in environmental decision making. Nowadays, advanced techniques to manage subjectivity, imprecision, uncertainty, vagueness, and variability are required in such complex evaluation process. We here propose a probabilistic fuzzy hybrid model to assess river water quality. Fuzzy logic reasoning has been used to compute a water quality integrative index. By applying a Monte Carlo technique, based on non-parametric probability distributions, the randomness of model inputs was estimated. Annual histograms of nine water quality variables were built with monitoring data systematically collected in the Colombian Cauca River, and probability density estimations using the kernel smoothing method were applied to fit data. Several years were assessed, and river sectors upstream and downstream the city of Santiago de Cali, a big city with basic wastewater treatment and high industrial activity, were analyzed. The probabilistic fuzzy water quality index was able to explain the reduction in water quality, as the river receives a larger number of agriculture, domestic, and industrial effluents. The results of the hybrid model were compared to traditional water quality indexes. The main advantage of the proposed method is that it considers flexible boundaries between the linguistic qualifiers used to define the water status, being the belongingness of water quality to the diverse output fuzzy sets or classes provided with percentiles and histograms, which allows classify better the real water condition. The results of this study show that fuzzy inference systems integrated to stochastic non-parametric techniques may be used as complementary tools in water quality indexing methodologies.  相似文献   

20.
中国流域水资源生态补偿的法律问题与对策   总被引:2,自引:0,他引:2  
随着我国经济社会的不断发展,水资源不足和水质污染引起的水危机已经成为许多地区可持续发展中的重要制约因素.在这种背景下,为了平衡环境、社会和经济多元利益,寻求先进的法律机制来调节平衡、保护流域生态环境、促进流域的可持续发展已成为一种共识.开展流域水资源生态补偿是实现流域上下游之间等相关方利益公平的关键所在.但由于我国缺乏生态补偿立法和相应的制度安排,流域水资源生态补偿目前仍面临许多问题:我国流域水资源生态补偿进展缓慢、法律制度滞后、部分法律法规彼此之间矛盾和相互冲突、流域水资源生态补偿的法律制度缺位、立法模式不适合当今流域生态环境问题解决等.本文通过对我国有关涉水法律中存在问题的分析,提出一些有关流域水资源生态补偿法律制度建设和完善的对策,以期对中国流域水资源生态补偿的推进和进一步实现水资源的可持续利用有所帮助.  相似文献   

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