首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
淮河(安徽段)南岸诸河流水质标识指数评价   总被引:1,自引:0,他引:1  
韩曦  王丽  周平  孙庆业 《湿地科学》2012,10(1):46-57
2010年夏季,对淮河(安徽段)南岸诸河流水质进行调查,共设置采样点160个,选取总氮、总磷、氨氮和化学需氧量4项水质指标,利用综合水质标识指数评价法(WQI)对淮河(安徽段)南岸诸河流水质进行评价。结果表明,淮河(安徽段)南岸诸河流水质达标率77%,超标的评价因子为氮营养盐和化学需氧量。污染物主要来自农业面源和生产、生活废水;水流流速、沉积物性质和周围环境对水质产生一定影响。  相似文献   

2.
Groundwater is the major source of drinking water in Nahavand city. However, the groundwater quality at the agricultural areas has been deteriorating in recent years. Ground water quality monitoring is a tool which provides important information for water management and sustainable development of the water resources in Nahavand. Hydrochemical investigations were carried out in an agricultural area in Nahavand, western Iran, to assess chemical composition of groundwater. In this study, 64 representative groundwater samples were collected from different irrigation wells and analyzed for pH, electrical conductivity, major ions, and nitrate. The results of the chemical analysis of the groundwater showed that concentrations of ions vary widely and the most prevalent water type is Ca–Mg–HCO3, followed by other water types: Ca–HCO3, Ca–Na–HCO3, and Na–Cl, which is in relation with their interactions with the geological formations of the basin, dissolution of feldspars and chloride and bicarbonate minerals, and anthropogenic activities. Thirty-seven percent of the water samples showed nitrate (NO3 ) concentrations above the human affected value (13 mg L−1). The phosphorous (P) concentration in groundwater was between 0.11 and 0.90 mg L−1, with an average value of 0.30 mg L−1, with all of the samples over 0.05 mg L−1. The most dominant class C2-S1 (76.5%) was found in the studied area, indicating that sodicity is very low and salinity is medium, and that these waters are suitable for irrigation in almost all soils. Agronomic practices, such as cultivation, cropping, and irrigation water management may decrease the average NO3 concentration in water draining from the soil zone.  相似文献   

3.
Diatoms consumed by Rio Grande silvery minnows (Hybognathus amarus) collected 104 years apart were used to deduce ecological requirements of this endangered species and to infer a possible cause of its decline based on environmental conditions in the Rio Grande. In 1874, foraged diatoms were largely motile, silt tolerant generalist and epipelic species (e.g. Navicula capitatoradiata, Navicula cryptotenella, Nitzschia palea, Sellaphora pupula) somewhat tolerant to pollution and indicative of eutrophic conditions, low dissolved oxygen, and high biological oxygen demand (BOD). In contrast, diatoms foraged in 1978 were mainly nonmotile epipsammic species (Fragilariaceae) sensitive to pollution and characteristic of low nutrient, oligotrophic conditions with high dissolved oxygen and low BOD. The large-scale difference in composition of the foraged diatom assemblages is consistent with a decline in nutrients and a shift in trophic state commonly associated with river regulation by dams. The results suggest that facilitating allochthonous input of detritus and nutrients into the Rio Grande ecosystem to meet foraging requirements for algivorous and detritivorous fish species such as H. amarus would be a good river restoration strategy.  相似文献   

4.
灌区渠系特征与灌溉水利用系数的Horton分维   总被引:1,自引:0,他引:1  
灌区渠系和自然河流水系存在着诸多相似之处,因此,对于灌区渠系体系是否存在及在何种程度下满足Horton 河系定律值得研究。以2010 年广东省53 宗样点灌区为研究对象,分类进行了适用性分析,发现只有四级渠系类灌区满足Horton 河系定律。在此基础上计算了各级渠系类灌区的渠系特征参数和分维值,并利用2007-2011 年实测数据,对其与灌溉水有效利用系数之间的作用关系进行了定性和定量分析,结果表明:渠系工程状况参数(0.1084) >下垫面参数(-0.3554) >渠系结构参数(-0.5189) >面积尺度参数(-0.5392) >渠系分维特征参数(-0.5536)。本研究对于定量表征灌区形态和渠系特征对灌溉水有效利用系数的影响提供了新的途径,研究结果对于指导灌区渠系规划建设,提高用水效率具有积极现实意义。  相似文献   

5.
Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures (sandy loam, sand) and three one-time irrigation volumes (60 mm, 20 mm, 0 mm) in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.  相似文献   

6.
The northern coastal part of Korinthia prefecture can be characterized as an agrotourism center that has grown and urbanized rapidly. The area is formed of recent unconsolidated material consisting of sands, pebbles, breccias and fine clay to silty sand deposits. These deposits host the main aquifer system of the area, which depends on groundwater as a water resource. Groundwater is the main source for irrigation in the area. A total water volume of 29.2×106–34.3×106 m3 yr−1 was estimated to recharge the aquifer system from direct infiltration of rainfall, streambed infiltration, irrigation return, artificial recharge via flood irrigation and lateral subsurface inflows. The present annual abstraction ranges between 39.2×106 and 44.6×106 m3 yr−1. Groundwater abstraction in dry years exceeds renewable freshwater resources by more than 38%. Approximately 79% of the total abstraction is consumed for agriculture supply. Water balance in the coastal aquifer system is in disequilibrium; a deficit, which ranges from 4.9×106 to 15.4×106 m3 yr−1 exists. The safe yield of the coastal aquifer system has been estimated at 37.1×106 m3 yr−1 for normal hydrological year and 32×106 m3 yr−1 for severely dry hydrological year. The total abstraction is greater than the recharge and the safe yield of the aquifer. The aquifer system has shown signs of depletion, seawater intrusion and quality contamination. The integrated water resources management, securing water in the future, should include measures that augment groundwater budget in the coastal aquifer of the study area.  相似文献   

7.
Sediment rating parameters and their implications: Yangtze River, China   总被引:4,自引:0,他引:4  
This study examines the characteristics of sediment rating parameters recorded at various gauging stations in the Yangtze Basin in relation to their controls. Our findings indicate that the parameters are associated with river channel morphology of the selected reaches. High b-values (> 1.600) and low log(a) values (< − 4.000) occur in the upper course of the steep rock-confined river, characterizing high unit stream power flows. Low b-values (< 0.900) and high log(a) values (> − 1.000) occur in the middle and lower Yangtze River associated with meandering reaches over low gradients, and can be taken to imply aggradation in these reaches with low stream power. Higher b-values (0.900–1.600) and lower log(a)-values (− 4.000 to − 1.000) characterize the reaches between Yichang and Xinchang, immediately below the Three Gorges. These values indicate channel erosion and bed instability that result from changes in channel gradient from the upstream steep valley to downstream low slope flood plain settings. Differences in channel morphology accompany these changes. Confined, V-shaped valleys occur upstream and are replaced downstream by broad U-shaped channels. The middle and lower Yangtze shows an apparent increase in channel instability over the past 40 years. This inference is based on sediment rating parameters from various gauging stations that record increasing b-values against decreasing log(a)-values over that time. Analysis of the sediment load data also reveals a strong correlation between changes in sediment rating curve parameters and reduction of annual sediment budget (4.70 × 108 t to 3.50 × 108 t/year, from the 1950s to 1990s), largely due to the damming of the Yangtze and sediment load depletion through siltation in the Dongting Lake. Short-term deviations from the general trends in the sediment rating parameters are related to hydroclimatic events. Extreme low b-values and high log(a)-values signify the major flood years, while the reverse indicates drought events. When compared with rivers from other climate settings, it is evident that the wide range of values of the Yangtze rating parameters reflects the huge discharge driven by the monsoon precipitation regime of eastern China.  相似文献   

8.
黄河流域环境对水资源开发承受力的思考   总被引:8,自引:0,他引:8  
尹国康 《地理学报》2002,57(2):224-231
根据黄河1919-1999年系列水沙资料,系统分析了其下游水沙变化时空过程,揭示了其发生断流原因及由此引发的环境问题,模拟了不同历史时期水情条件下环境用水需求量,并对如何提高黄河水资源开发承受能力,如何满足其环境用水提出看法。  相似文献   

9.
挠力河流域水稻生育期水分供需特征研究   总被引:1,自引:0,他引:1  
周浩  马泉来  邹朝晖 《地理科学》2021,41(3):534-543
基于MODIS遥感序列数据、常规气象数据、水稻生育期资料,利用区域遥感蒸散模型和水分盈亏评价模型,从栅格尺度揭示挠力河流域水稻生育期水分供需特征及水分盈亏状况.研究发现:①全生育期的需水均值和降水均值分别为673.88 mm和291.81mm,且各生育期的水分供需态势存在较大差异.中期的有效降水量与需水量分别占全生育期...  相似文献   

10.
Methods of calculating the basic hydrological characteristics of a water resource assessment, as well as the planning and management of their long-term use are based upon the concept of stationarity of long-term flow fluctuations. However, data of researches by hydrologists and climatologists clearly indicate that there are long-period changes in the characteristics of precipitation and river flow. This article discusses the variations of annual precipitation and river flow in the Ishim River Basin in Kazakhstan, based on the W, C and E classification developed by G.Y. Vangengeim who analyzed the long-term variability of anomalies by the number of days with some form of atmospheric circulation. From this study, the largest anomaly of the macro-circulation processes was revealed, and a comparative analysis of the number of days with various forms of atmospheric circulation and precipitation anomalies was made. It was demonstrated that the nature of atmospheric circulation depends on the distribution of precipitation; however, precipitation is also highly dependent on local physiographic conditions. The analysis of anomalous precipitation during the maximum number of days of positive anomalies with various forms of atmospheric circulation was also carried out. This study presents some results from the preliminary analysis of annual river flow linked with forms of atmospheric circulation.  相似文献   

11.
The river Narmada is a major source of fresh water for the highly populated areas, predominantly the rural populations in Madhya Pradesh (Central India) and Gujarat (Western India). Modernization and industrialization in these areas have become a matter of concern due to changing environment and increasing social activities that influence the quality of water directly or indirectly. This investigation was undertaken to evaluate the quality of water along the banks of the river Narmada at different sampling sites using physico-chemical and bacteriological methods. The samples collected were analyzed per standard method parameters and were measured in situ. The correlation matrix indicated strong mutual dependency between the measured parameters (P < 0.05). Principal components analysis of the data indicates that two components (PC1 and PC2) influence the water quality to the extent of 57.4, 64.5 and 61.0% during rainy, winter and summer seasons, respectively. The mean values of the physico-chemical parameters of the river water samples were consistently higher than the levels certified by the World Health Organization and other regulatory bodies as polluted water. The presence of coliform bacteria in the water samples warrants for proper measures to reduce the pollution at point sources and requires proper remediation strategies to combat contamination in the river water.  相似文献   

12.
河流水质风险评价的灰色-随机风险率方法   总被引:3,自引:2,他引:3  
胡国华  夏军  赵沛伦 《地理科学》2002,22(2):249-252
提出了量化影响河流水质的随机不确定性与灰色不确定性的水质超标灰色-随机风险率概念,建立了水质超标灰色-随机风险率评价模型。在水质单项参数评价模型中,将河流污染物浓度变量的分布处理成灰色概率分布,将污染物浓度超过水质类别标准值的风险率处理成灰色概率,即水质超标灰色-随机风险率。在水质综合评价模型中,河流水环境系统被考虑为担任某一使用可能的可靠性系统,而任意一种水质参数超标意味着河流水体使用功能不能得到应有的保证,也即表明水体综合评价超标,最后借鉴系统可靠性分析的理论和方法计算水质综合超标率。该方法应用于黄河花园口断面重金属污染风险评价。  相似文献   

13.
Accurate information on land use and land cover (LULC) is critical for policy decisions especially for management of land and water resources’ activities in large river basins around the world. Phenology based LULC classification is the most promising approach particularly in the areas with diversified cropping patterns. Sometimes in large river basins, local climate and topography provides two different phenological information sets for the same crops in the same season. Based on accurate phenological information of the main crops in spatially segregated units, the remote sensing based classification was used to map the LULC changes for a period of 2003–2013 in the Kabul River Basin (KRB) of Afghanistan. We used remotely sensed Normalized Difference Vegetation Index (NDVI) products of Moderate-resolution Imaging Spectroradiometer (MODIS) from Terra (MOD13Q1) and Aqua (MYD13Q1) with 250 m spatial resolution for this study. The overall accuracy (mean) of the LULC classification throughout the study period was around 68.15% ± 9.45while the producer and user accuracies (mean) were 75.9 ± 11.3% and 76.4 ± 11.2%, respectively. Results show that the cropping patterns vary significantly in the spatially disaggregated units. From 2003 till 2013, the ground coverage of wheat, barley and rice was increased by 31%, 7% and 32%, respectively. Overall, there has been only 2% increment in the agricultural area across the KRB between 2003 and 2013. This relatively increased trend of land cover change has taken place as a result of partial improvement in political stability as well as investment in irrigation infrastructure and agricultural development in the region. This study further provides insight to develop new agriculture strategies in order to maintain the ecosystem required to fulfil the rising food demands.  相似文献   

14.
In order to relate macroinvertebrate fauna to electrical conductivity (EC), a survey of selected orders of macroinvertebrates was conducted in the Glenelg, Hopkins, Merri and Barwon River Catchments in south-west Victoria, Australia. The survey consisted of sampling 21 paired sites at confluences of streams. There was little difference between the in-stream habitat but there was a range of differences in EC between each of the paired sites. The dissimilarity of macroinvertebrate fauna between the paired sites was compared to the proportional difference in EC and other water quality variables (dissolved oxygen, water temperature, pH, NO2−N, NO3−N, PO4 and turbidity). This allowed the elimination of EC being confounded with geographical scale parameters and took into account other water quality parameters that may be confounded with EC. A positive relationship was found between the dissimilarity of the fauna at each of the two paired sites and the proportional difference in EC. No such relationship was found for any other measured water quality variable. The results of this survey show that macroinvertebrate community structure is associated with EC of the river systems investigated after eliminating large scale geographical patterns, in-stream habitat and the measured water quality parameters.  相似文献   

15.
Shanghai is a megacity that increasingly relies on water drawn from the Yangtze River estuary. During periods of low flow, water in the estuary can become too saline for use in city water supplies. River flow is measured at the Datong gauging station 680 km upstream from the river mouth. Several existing and planned river water extractions are located below Datong, including the Eastern Route of the South-North Water Diversion Project (ERP). The effect of these extractions on discharge into the estuary and the associated salinity levels may be significant, even though the extractions are not reflected in the discharge at Datong. We estimate the effects of these downstream extractions on water discharge into the estuary (rather than at Datong), particularly the critical discharge level below which salinity compromises water security in Shanghai. Our results show that the ERP will cause the discharge into the estuary to fall below critical levels between December and February in dry years and January to February in normal years. Future water transfer projects along the lower Yangtze River will further compound the problem. Maintaining Shanghai's water security is therefore a significant challenge for China's water resource management institutions.  相似文献   

16.
新疆塔里木河流域水资源承载力评价研究   总被引:14,自引:3,他引:11  
结合塔里木河2002年自然、社会和经济以及水资源资料,选取了耕地灌溉率、水资源利用率、供水模数、需水模数、人均供水量、生态用水率6个主要因素作为评价因素,应用模糊综合评判模型对塔里木河流域水资源承载能力进行了评价研究。结果表明,流域水资源开发利用已经达到相当规模,在现有经济技术条件下,该地区的水资源承载潜力已相对较小,水资源供需矛盾突出,应由耗水型经济结构向节水型经济结构转变,加强水资源的综合管理,以便科学、合理地利用流域内有限的水资源。  相似文献   

17.
The aim of the study is the analysis of runoff and water quality changes in the Upper Oder River Basin above the Krapkowice gauging station (catchment area A = 10 720.6  km2).The issue of water quality is of particular importance to Poland, which has comparatively poor water resources compared with many countries of the European Union (EU). What is more, large pollutant loads in the upper course of the Oder pose huge problems for water consumers and users in its middle and lower course (including Germany) and pollute the Baltic Sea.Changes in 7 indices of water pollution, including BOD5 and COD (synthetic indices), sulphates, chlorides and suspended matter (mineral substances) and nitrates and phosphates (biogenic substances), were investigated for 8 monitoring sites. The study spans the period before and after political transformation in Poland and the Czech Republic, which significantly altered the economies of these countries. In addition, the patterns of runoff changes were analysed at 3 gauging stations: Chałupki, Krzyżanowice and Miedonia, which were also water quality monitoring points. The analysis encompassed 2 periods: 1970–2000 and 1991–2000.The results demonstrated that poor water quality in the Oder improved significantly during the 1990s, as the result of closure of many industries and plants, improvement of sewage treatment and noticeable increases in runoff causing greater dilution of pollutants.As the EU Water Framework Directive is implemented, better water and sewage management can be expected that will contribute to further improvement of water quality in the Oder. However, problems that remain to be solved are the issues of saline mine waters and surface washings and the long-term accumulation of many hazardous substances in bottom sediments in rivers and reservoirs.  相似文献   

18.
通过对吉林省四大水系的主要河流在2005~2006年内采样,测其高锰酸盐指数(PV)、化学需氧量(COD)和总有机碳(TOC),用最小二乘法对PV—TOC、COD—TOC和COD—PV进行线性回归,并进行相关关系的显著性检验,建立吉林省四大水系主要河流PV—TOC、COD—TOC和COD—PV的定量关系模型。结果表明,吉林省四大水系主要河流中PV—TOC、COD—TOC和COD—PV之间均具有显著的线性相关关系,不同水系的线性相关关系之间存在一定的差异。  相似文献   

19.
Interconnected river system networks is a national water conservancy strategy in China and focus of research. Here we discuss the classification system, material and energy exchange between rivers and lakes, various dynamic flows and ecological functions of river-lake interconnected relationships. We then propose a novel method for the health assessment of river systems based on interconnected water system networks. In a healthy river system there is “material and energy exchange” and it is the first and foremost relationship of material and energy exchange between rivers and lakes. There are unobstructed various “flows” between rivers and lakes including material flows (water, dissolved substances, sediments, organisms and contaminants), energy flows (water levels, flow and flow velocity), information flows (information generated with water flows, organisms and human activities) and value flows (shipping, power generation, drinking and irrigation). Under the influences of nature and human activity, various flows are connected by river-lake interconnection to carry material and energy exchange between rivers and lakes to achieve river-lake interactions. The material and energy exchange between rivers and lakes become one of the approaches and the direct driving forces of changes in river-lake interconnected relationships. The benignant changes in river-lake interconnected relationship tend to be in relatively steady state and in ideal dynamic balance.  相似文献   

20.
Review article: Silt and the future development of China's Yellow River   总被引:1,自引:0,他引:1  
Silt loading is a critical problem in the use of the Yellow River for irrigation, domestic, and industrial water supplies. Nearly all of the silt comes in runoff from the immense and highly erodible Loess Plateau. Salinity has a secondary but widespread effect on irrigation development and groundwater quality. Engineering structures and expanded irrigation have reduced the silt load in the lower reach of the river by half over the last 50 years. Still, the level of the river bed continues to rise higher above the surrounding North China Plain. Millions of rural and urban lives are threatened by the possibility that an embankment will break and unleash a horrendous flood, as had happened numerous times prior to 1949. Earthquakes could cause similar castrophes. Increased populations in cities, expansion of irrigated land, and rapid industrialization have brought about locally severe water shortages. This, in turn, has led to surface and groundwater pollution by salt and heavy metals, lowering of groundwater levels, land subsidence, and salt water intrusion from the Bo Sea. Interbasin water transfers from the Yangtze River in the south to relieve water shortages in the north have been proposed for decades but remain controversial. The high cost of dams, canals, tunnels, pumping, and water control systems needed for the transfer has been a major objection. Other factors have been the adverse environmental impact in both the Yellow and Yangtze river watersheds of transfers and, importantly, the questionable need of the transfers if water conservation practices were used widely and effectively.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号