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1.
研究鄱阳湖入、出湖污染物通量是加强鄱阳湖及长江水功能区限制纳污红线管理的前提,是建立鄱阳湖水质预测模型的基础.基于2008-2012年鄱阳湖8条主要入湖河流、出湖口的逐月水量、水质同步监测资料,根据污染源特征优选算法,计算总磷(TP)、氨氮(NH3-N)、高锰酸盐指数(CODMn)的入、出湖污染物通量,并分析时空变化特征及影响因素.结果表明:(1)出湖口和乐安河入湖口断面的NH3-N、TP及昌江入湖口断面的TP,以点源污染为主,采用每月瞬时通量作为月平均通量的算法更准确;其余以非点源污染为主,采用瞬时污染物浓度与月平均流量之积来计算月平均通量更准确.(2)2008-2012年CODMn、NH3-N和TP年平均人湖通量分别为304398、53063和9175 t,年平均出湖通量分别为367436、45814和8452t.8条入湖河流每年的入湖水量、CODMn通量和个别年份的NH3-N、TP通量小于出湖,这主要是因为未计算区间产流及相应排污和采砂引起的内源污染.(3)入、出湖污染物通量在年际间主要受水量影响而呈现W型波动变化趋势,CODMn、NH3-N、TP入湖通量及CODMn出湖通量均集中在汛期,NH3-N、TP出湖通量则是冬季较多(低水位下湿地植被净化作用受限).入湖TP、NH3-N、CODMn通量主要来自赣江、信江、乐安河,而NH3-N、TP浓度最高的是乐安河、信江.  相似文献   

2.
天津中心城区河网氮磷污染与富营养化特征   总被引:1,自引:0,他引:1  
2013年底天津中心城区河道全部连通,形成中心城区河网.为了掌握河网形成后的水质状况,于2014年3月-2015年2月进行了为期1年的定点水质监测,并对其水体氮、磷时空分布及富营养化特征进行分析.结果表明,河网水体氮污染严重,以铵态氮(NH+4-N)为主;磷污染程度较轻,主要形态为磷酸盐(PO3-4-P);河网水体中氮、磷浓度顺水流方向均呈上游高、下游低的空间分布特征;氮、磷各项指标浓度时间变化趋势基本一致,3月均最高,10月均最低,冬季处于相对较低水平;与河网形成前相比,海河干流NH+4-N、总磷(TP)和PO3-4-P浓度年平均值分别下降6.5%、14.7%和16.4%,津河总氮、NH+4-N、硝态氮、TP和PO3-4-P浓度年平均值分别降低18.6%、34.5%、12.9%、31.6%和32.5%,表明河网形成后氮、磷污染程度较之前有所改善,其中津河改善较为明显;河网水体全年处于中度富营养状态,主要为磷限制性状态;河网富营养化防治应遵循以控制营养盐为主的控源、截污、水环境增容和生态补水策略.  相似文献   

3.
水产养殖清塘过程中的排水是造成周边水环境污染的重要环节,但对此环节中污染物排放特征和影响程度的研究仍相对不足。为有效减少清塘过程的排水对环境的污染,推进水产养殖业绿色发展,本研究选取典型鱼类集约化养殖区,通过高频采样和监测,分析了阶段式排水时混养鱼塘尾水中的悬浮物、有机物和营养盐等指标的浓度变化,明确污染物的排放特征,同时分析受纳水体不同断面的水质变化情况。研究结果表明:总悬浮物浓度(TSS)、高锰酸盐指数(CODMn)、总磷(TP)、总氮(TN)和氨氮(NH3-N)浓度随着持续排水呈上升趋势,在排水末期污染物浓度均快速上升,磷酸盐磷(PO43--P)浓度仅在排水末期骤升,硝态氮(NO3--N)浓度随排水持续下降,亚硝态氮(NO2--N)浓度随排水先上升后下降;根据《淡水池塘养殖水排放要求》二级标准,排水末期TN、TP、TSS浓度超标倍数分别达4.70、6.66、206.90;尾水流量与河流量约以1/200的比例...  相似文献   

4.
Reclaimed water is efficiently used to recover the dry river, but river water and groundwater may be impacted considering the water quality. Thus, it is critical to study the factors controlling water chemistry. Samples of reclaimed water, river and groundwater were collected monthly from January to September in 2010, in Huai River (North China). And samples were analyzed for major 15 physio-chemical parameters. Using hierarchical cluster analysis, 9 months are divided into two distinct groups, which show the clear temporal variation. In reclaimed water and river water, one group includes February, while the other includes other months. In shallow and deep groundwater, one group includes months from January to April, while the other encompasses others. Monitoring stations are classified into three groups. Group A with high value of ions and nitrogen (order: NH4-N > NO3-N > NO2-N) includes reclaimed water and river water. Group B with moderate concentration and nitrogen (order: NO3-N > NH4-N > NO2-N) includes all shallow groundwater and one deep groundwater. Group C with the low value and nitrogen (order: NO3-N > NO2-N > NH4-N), includes two deep groundwater. Using multivariate analysis and ionic relationships, river water chemistry is found to be controlled by reclaimed water and evaporation process; chemistry in shallow groundwater and one deep groundwater, with type of Na–Ca(Mg)–HCO3–Cl, is controlled by dissolution of calcite, carbonate weathering. Additionally, reactions of nitrification, denitrification and cation exchange occur in the infiltration of reclaimed water; chemistry in the other deep groundwater, with type of Ca–Mg–HCO3–Cl, is controlled by dissolution of calcite, carbonate weathering and denitrification.  相似文献   

5.
环太湖江苏段入湖河道污染物通量与湖区水质的响应关系   总被引:1,自引:1,他引:0  
基于2008-2018年环太湖江苏段入湖河道污染物通量及湖区水质数据,从时空变化及相关关系两个方面探讨了入湖污染物通量与湖区水质的响应关系,并分析了污染物进入湖体影响水质的主要因子.结果表明:太湖污染减排已见成效,氨氮、总氮、高锰酸盐指数和化学需氧量入湖污染物通量整体呈下降趋势,年均下降率分别为8.0%、2.0%、1.6%和2.2%,湖体氨氮和总氮时间格局响应较好,年均下降率分别为2.1%和2.3%.湖体氨氮、总氮、总磷、高锰酸盐指数和化学需氧量与入湖污染物通量整体由西北部、西部湖区向东南部、东部湖区递减,空间格局上响应基本一致.全湖区年尺度总氮、氨氮浓度与入湖河道污染物通量分别呈显著正相关、极显著正相关关系;影响湖区总氮、氨氮的主要因子为入湖河道的总氮、氨氮浓度,其次为入湖河道浓度与原湖区水质差值,因此亟需加强入湖河道水质浓度的控制.  相似文献   

6.
Reduction of the Concentration of Bacteria and Coliphages along the Flowing Stretch of a Treated Sewage Channel The efficiency of surface waters to eliminate E. coli, fecal streptococci, Salmonella spp., and coliphages was evaluated in a small river which receives treated wastewater and which is rich in submerged macrophytes. The study took place between April and December, 1994. Total colony count, BOD5, O2 concentration and water temperature were determined in the river as well. As the river does not receive additional water downwards along its 17.2 km course, dilution effects could be ruled out as the cause for the elimination of the microorganisms. The reduction is assumed to happen rather due to sedimentation, grazing, and adsorption to the submerged waterplants. Immediately after discharge of the wastewater, the river water contained about 105 cfu/100 mL E. coli and 104 cfu/100 mL fecal streptococci, about 1000 pfu/100 mL coliphages, and, as a rule, was positive for salmonella in 10 mL. The reduction of E. coli, fecal streptococci, salmonella, clostridia, and coliphages at the end of the course was 1 to 2 orders of magnitude. This reduction took place mainly within the first 4.7 km, a part in which, due to low flowing velocities, suspended solids settle down efficiently. Besides, at the end of this part the submerged waterplants are especially abundant. The reduction of suspended solids correlated positively with that of BOD5, bacteria, and coliphages. The reduction of microorganisms was not sufficient to fulfill the requirements of the European Community guidelines for bathing waters and for surface waters used as drinking water source. The regenerating capacity of surface waters is not sufficient to eliminate pathogens from convenionally treated wastewater. Therefore, tertiary treatment is necessary to keep receiving waters reasonably free from pathogens.  相似文献   

7.
根据2007-2014年淀山湖湖体每月高锰酸盐指数(CODMn)、氨氮(NH3-N)、总氮(TN)和总磷(TP)等水质资料和青浦区气象局月平均气温、降水量和日照时数等气象资料,运用数理统计方法和特征值比较法分析淀山湖湖体CODMn、NH3-N、TN和TP等水质资料变化规律及温度、降水和日照时数等对水质的影响.结果表明:(1)气象条件影响淀山湖湖体水质.平均气温、日照时数影响NH3-N、TN和TP浓度,表现在平均气温高、日照时数多,NH3-N、TN浓度降低,相反平均气温低、日照时数少,NH3-N、TN浓度升高;平均气温高,也会使TP浓度上升,平均气温低,TP浓度降低.降水对水体中CODMn、NH3-N和TN等浓度有稀释作用,降水量多的月份其浓度偏低,相反降水量少的月份其浓度偏高.(2)受气象条件影响,CODMn、NH3-N、TN和TP有季节变化.CODMn浓度4-9月较高,10月翌年3月较低;NH3-N、TN浓度最高值出现在2-4月前后,最低值出现在7-10月;TP浓度最高值出现在7-8月,最低值出现在10月翌年5月.(3)淀山湖CODMn、NH3-N、TN和TP浓度呈下降趋势.  相似文献   

8.
为进一步揭示阳澄湖入湖河道的污染物来源,提出相应的治理对策,以2017—2021年阳澄湖入湖河道水质监测数据为基础进行分析讨论。依据入湖水量选取10条主要入湖河道进行分析,其中位于阳澄湖东岸的白曲港在七浦塘拓浚工程建成之前主导流向为出湖,工程建成后,通过Pearson相关分析证实了其流向与七浦塘引水时的水力关系,因此白曲港被选为主要入湖河道。采用距平系数法、系统聚类法和物元分析法将阳澄湖主要入湖河道分为3个类别:第1类别包括白荡、蠡塘河、北河泾、永昌泾4条河道,第2类别包括渭泾塘、界泾和施家斗港3条河道,第3类别包括南消泾、七浦塘和白曲港3条河道。使用因子分析法进行因子分析,第1类别河道的因子为高锰酸盐指数(CODMn)、氨氮(NH3-N)、溶解氧(DO)和总磷(TP),第2类别河道的污染因子为NH3-N、总氮(TN)、pH、TP和DO,第3类别河道的污染因子为pH、TP、TN和DO。通过对上游河道水质情况分析、文件研究以及实地调查等方式得出第1类别河道区域的污染源主要为工业污染源和生活污染源,第2类别河道区域污染源主要为工业污染源与种植业污染源,第3类别河道污染源主要为陆地水产养殖污...  相似文献   

9.
Danube river water samples were saturated with mineral oil, and then the primary production (gross) was determined by means of the light-dark bottle method (oxygen) in situ at depths of 0.1… 1.5 m in comparison with untreated samples. Samples were exposed for half a solar day alternately during the first and second half-days. Investigations carried out between March and October for periods of 14 days showed a mean production of 2.56 g · m?2d?1 O2, which was reduced by 36% due to 12.6 mg/l hydrocarbons. Production decreases with the water depth from 6.2 to 0.9 mg · l?1d?1 02, whereas the inhibition by hydrocarbons increases from 31 to 41%.  相似文献   

10.
S. Rehana  P. P. Mujumdar 《水文研究》2013,27(20):2918-2933
This paper presents an approach to model the expected impacts of climate change on irrigation water demand in a reservoir command area. A statistical downscaling model and an evapotranspiration model are used with a general circulation model (GCM) output to predict the anticipated change in the monthly irrigation water requirement of a crop. Specifically, we quantify the likely changes in irrigation water demands at a location in the command area, as a response to the projected changes in precipitation and evapotranspiration at that location. Statistical downscaling with a canonical correlation analysis is carried out to develop the future scenarios of meteorological variables (rainfall, relative humidity (RH), wind speed (U2), radiation, maximum (Tmax) and minimum (Tmin) temperatures) starting with simulations provided by a GCM for a specified emission scenario. The medium resolution Model for Interdisciplinary Research on Climate GCM is used with the A1B scenario, to assess the likely changes in irrigation demands for paddy, sugarcane, permanent garden and semidry crops over the command area of Bhadra reservoir, India. Results from the downscaling model suggest that the monthly rainfall is likely to increase in the reservoir command area. RH, Tmax and Tmin are also projected to increase with small changes in U2. Consequently, the reference evapotranspiration, modeled by the Penman–Monteith equation, is predicted to increase. The irrigation requirements are assessed on monthly scale at nine selected locations encompassing the Bhadra reservoir command area. The irrigation requirements are projected to increase, in most cases, suggesting that the effect of projected increase in rainfall on the irrigation demands is offset by the effect due to projected increase/change in other meteorological variables (viz., Tmax and Tmin, solar radiation, RH and U2). The irrigation demand assessment study carried out at a river basin will be useful for future irrigation management systems. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

11.
曝气充氧对城市污染河道内源铵态氮释放的控制   总被引:3,自引:1,他引:2  
凌芬  刘波  王国祥  许宽  周锋  杜旭 《湖泊科学》2013,25(1):23-30
以城市污染河道沉积物和上覆水为研究对象,利用模拟实验方法,探讨不同曝气充氧方式(水曝气EW、底泥曝气ES)对污染河道內源铵态氮(NH4+-N)释放的影响.研究结果发现:从间隙水和沉积物中NH4+-N的削减效果来看,底泥曝气均要优于水曝气;实验结束后,底泥曝气组沉积物与间隙水中NH4+-N含量分别减少63.39%和43.33%,水曝气组分别减少了7.54%和13.98%;从沉积物-水界面NH4+-N的扩散通量变化来看,水曝气组界面通量高于对照组,其变化规律与对照组相似;底泥曝气组沉积物-水界面NH4+-N扩散通量变化过程完全不同于其它两组,在整个试验周期内(除第5 d以外),底泥曝气组的通量低于水曝气组,在第15 d最低,为13.73 mg/(m2.d),仅为水曝气组和对照组的14.68%和19.93%,表明底泥曝气组沉积物NH4+-N的释放潜力低于水曝气组沉积物.  相似文献   

12.
三峡大坝上下游水质时空变化特征   总被引:6,自引:2,他引:4  
为探索三峡大坝上下游(坝上99.9 km、坝下63.0 km、全长162.9 km)水质时空变化特征,运用主成分分析和方差分析对2016年近坝段水质时空变化特征进行了分析.主成分分析表明,水文因子流量(Q)、气温(T)、水位(Z)和水质因子(水温(WT)、pH、电导率(EC)、溶解氧(DO)、悬浮物(SS)、高锰酸盐指数(CODMn)、硫酸盐(SO42-)、氟化物(F-)、总硬度(T-Hard)、硝态氮(NO3--N)、总氮(TN)和硒(Se))的变化主导着研究区域水质变化;各采样点主成分得分和双因素方差分析结果显示研究区域水质因子时间变化主要呈现出季节和不同水库运行时期的差异.消落期(2-5月),T-Hard、F-、SO42-和EC是影响河流水质变化的主导因子;汛期(7-8月),Q、SS、CODMn、NO3--N、TN和Se是影响河流水质变化的主导因子;T和WT主导着汛末(9月)河流水质变化,并引起了DO等理化特性的变化;高水位运行期(12月),Cl-是影响河流水质变化的主导因子.现阶段,DO、有机污染物(CODMn)、无机盐(SO42-和F-)、营养盐类(NO3--N和TN)、类金属元素(Se)和水体的矿化程度(T-Hard)的变化主导着区域水质的变化,是三峡大坝近坝段水域水质的控制因子.方差分析表明,河流的理化特性(DO、pH和SS)、营养盐组分构成(NH3-N和NO3--N)、无机盐类(EC和Cl-)、石油类有机污染物及粪大肠菌群(FC)等指标在坝上与坝下断面存在显著性差异.气温、水温、降雨、含沙量的季节性影响因素和水库调度运行模式是影响近坝段水质时间差异的主要因子;空间差异主要受城区污染排放和三峡水库调度引起的坝上和坝下水文和水动力学条件差异影响.因此控制研究区域因人类活动等造成的外源性污染,并针对不同类污染物质的季节变化特征实施合理的水库运行方式是近坝段水质提升的关键.  相似文献   

13.
为研究太湖流经不同类型缓冲带的入湖河流水体氮污染特征,于2011年9 12月连续对流经4种不同类型缓冲带入湖河流沿程共32个样点进行采样,分析各样点的氮浓度及变化趋势.结果表明,流经农田型缓冲带入湖河流中总氮浓度由缓冲带外进入缓冲带内不断减小,到入湖河口处有轻微上升;流经养殖塘型、村落型缓冲带入湖河流中总氮浓度由缓冲带外进入缓冲带内变化不大,到接近入湖河口时浓度显著升高;流经生态型缓冲带入湖河流中各氮元素形态沿程不断降低.在流经4种类型湖泊缓冲带入湖河流中,流经农田型、养殖塘型和生态型缓冲带的入湖河流以硝态氮为氮元素的主要存在形态,而流经村落型缓冲带的入湖河流中硝态氮和铵态氮同为氮元素的主要存在形态.总氮浓度、铵态氮浓度与缓冲带类型均呈极显著正相关关系,外源污染排入对流经缓冲带的入湖河流中氮元素总量及形态产生较大影响.流经生态型缓冲带入湖河流净化效果最佳,总氮、硝态氮和铵态氮浓度削减率分别为60%、53%和61%.  相似文献   

14.
以流经四川绵阳市安县河流茶坪河为研究对象,在对该河流水污染负荷、水环境现状及水环境功能充分调查的基础上,结合该河流的水文特征和排水规划以及四川省绵阳市环境监测站2005年实测的数据,采用二维浅水水动力学—水质模型方程组对茶坪河的各监测断面CODCr和NH3-N的浓度场进行了计算模拟和对比,并用一维水环境容量计算模型计算了该河流的水环境容量,提出了具体的总量控制措施.结果表明:用二维浅水水动力学—水质模型方程组计算各监测断面的CODCr和NH3-N与实测值相差不大;茶坪河水环境容量CODCr为123.96t/a,NH3-N为42.95t/a,所排放的CODCr量、NH3-N量已经超过该流域容量,出水水质已超过水质保护目标Ⅲ类标准.  相似文献   

15.
Bacterioplankton play critical roles in biogeochemical cycling. Although spatial and temporal variations in bacterioplankton community compositions (BCCs) within individual habitat have been reported, knowledge gaps remain for studies conducted within different habitats. In this work, we examined the seasonal and spatial variability of BCCs in Nanfei River and Lake Chaohu which had significant environmental heterogeneity using a high-throughput sequencing technique of 16S rRNA gene amplicons. The results showed that spatial variation has a more obvious impact on the BCCs than seasonal changes. The microbial diversity gradually decreased and BCCs changed obviously along water flow direction from Nanfei River to the western and estern parts of Lake Chaohu over all seasons. LEfSe analysis showed that Nanfei River had higer abundance of species belonging to the orders Rhodocyclales, Methylococcales, Campylobacterales and Flavobacteriales, samples from eastern part of Lake Chaohu were abundant in taxonomies including the order Rickettsiales, while the western part had high abundance of taxonomies belonging to the order Chroococcales. The redundancy analysis (RDA) indicated that BCCs in Nanfei River were associated with high nutrient (TP, PO4-P, TN, NH3-N, NO2-N and NO3-N) concentrations and electrical conductivity. Variance partitioning RDA analysis indicated that the combined effects of all variables may be most important affecting BCCs. This study may provide a framework for modeling the change in bacterioplankton communities through different habitats from a river to lake.  相似文献   

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Abstract

Rivers have been channelized, deepened and constrained by embankments for centuries to increase agricultural productivity and improve flood defences. This has decreased the hydrological connectivity between rivers and their floodplains. We quantified the hydrological regime of a wet grassland meadow prior to and after the removal of river embankments. River and groundwater chemistry were also monitored to examine hydrological controls on floodplain nutrient status. Prior to restoration, the highest river flows (~2 m3 s?1) were retained by the embankments. Under these flow conditions the usual hydraulic gradient from the floodplain to the river was reversed so that subsurface flows were directed towards the floodplain. Groundwater was depleted in dissolved oxygen (mean: 0.6 mg O2 L?1) and nitrate (mean: 0.5 mg NO3 ?-N L?1) relative to river water (mean: 10.8 mg O2 L?1 and 6.2 mg NO3 ?-N L?1, respectively). Removal of the embankments has reduced the channel capacity by an average of 60%. This has facilitated over-bank flow which is likely to favour conditions for improved flood storage and removal of river nutrients by floodplain sediments.

Editor Z.W. Kundzewicz; Associate editor K. Heal

Citation Clilverd, H.M., Thompson, J.R., Heppell, C.M., Sayer, C.D., and Axmacher, J.C., 2013. River–floodplain hydrology of an embanked lowland Chalk river and initial response to embankment removal. Hydrological Sciences Journal, 58 (3), 627–650.  相似文献   

18.
In order to help evaluate the trends in the NO3-N concentration in groundwater with a view to preventing further degradation in water quality in the future, a distributed groundwater quality model was constructed for the Nasunogahara basin. The best fit for the groundwater table elevations by the flow component of the model was achieved with average mean absolute errors (MAEs) of 0·92 m for the calibration period and 0·83 m for the validation period. Moreover, the best fit for the NO3-N concentration by the water quality component was achieved with average mean relative errors (MREs) of 29·8% for the calibration period and 30·3% for the validation period. After developing a robust model, various change scenarios were tested; specifically, the effects of effluent load control and a decrease in paddy field area on the NO3-N concentration in groundwater were predicted. The most intensively farmed area contributed about 40% of the total effluent load because of livestock farming in the basin. When the effluent load from this area was decreased by 50%, the average NO3-N concentrations at sites S1, S2 and S3 were reduced by about 15%; however, the average concentrations at S4 and S5 were reduced by only 1%. Furthermore, when the total effluent load from the concentrated livestock area was removed completely, the average groundwater NO3-N concentrations at S1, S2 and S3 were reduced by about 30% as compared with the original calculated results. In contrast, decreasing the area of the paddy fields in the basin did not greatly influence the groundwater NO3-N concentration. In the case of a 70% reduction in paddy field area, average NO3-N concentrations increased by about 7% at S1, S2 and S3. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

19.
Non‐point source (NPS) pollution from agricultural land is increasing exponentially in many countries of the world, including India. A modified approach based on the conservation of mass and reaction kinetics has been derived to estimate the inflow of non‐point source pollutants from a river reach. Two water quality variables, namely, nitrate (NO3) and ortho‐phosphate (o‐PO4), which are main contributors as non‐point source pollution, were monitored at four locations of River Kali, western Uttar Pradesh, India, and used for calibration and validation of the model. Extensive water quality sampling was done with a total of 576 field data sets collected during the period from March 1999 to February 2000. Remote sensing and geographical information system (GIS) techniques were used to obtain land use/land cover of the region, digital elevation model (DEM), delineation of basin area contributing to non‐point source pollution at each sampling location and drainage map. The results obtained from a modified approach were compared with the existing mass‐balance equations and distributed modelling, and the performances of different equations were evaluated using error estimation viz. standard error, normal mean error, mean multiplicative error and correlation statistics. The developed model for the River Kali minimizes error estimates and improves correlation between observed and computed NPS loads. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

20.
Nutrients are important building blocks for healthy aquatic ecosystems and are generally nontoxic; but they can change with alteration in environmental parameters. The main objective of this study was to consider the seasonal variability of NO 3 , PO 4 3– and total suspended solids (TSS) concentrations in water. The study sites, stream crossings (L30, L15) and river (R), are located in the hyrcanian forests, district 1 of Darabkola forest. The sampling was conducted in winter and spring. Water samples were taken into plastic bottles, labeled, and carried out to the laboratory for NO 3 , PO 4 3– and TSS analysis. T-test results showed that there was a seasonal change in nutrient concentrations (p < 0.05) except for NO 3 concentration at L30. Also, there was no significant seasonal change in TSS concentrations at all stations. Pearson correlation analysis did not reveal the same trend. Further analysis showed that the effect of road age on water quality parameters was statistically significant for PO 4 3– in spring and winter. Atmospheric precipitation plays vital role in nutrient loss and increasing concentration of suspended sediment. To prevent soil erosion from activities and discharge of wastes in the vicinity of river and stream an effective management should be planned and enforced.  相似文献   

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