典型新兴污染物在“源-河-库”系统中的赋存特征及生态风险——以东江水源区为例(二)

科研工作是行业发展的必要技术储备环节,也是成果转化推动产业进步的重要前序环节。对科研工作的回顾与展望,有助于梳理技术发展脉络,并为后续的产学研互动提供建议。本期栏目就《东江上游典型集水区水环境风险控制技术集成与综合示范》(2014ZX07206001)项目进行回顾剖析,为相关从业人员提供后续工作思路。

典型新兴污染物在“源-河-库”系统中的赋存特征及生态风险——以东江水源区为例(一)

科研工作是行业发展的必要技术储备环节,也是成果转化推动产业进步的重要前序环节。对科研工作的回顾与展望,有助于梳理技术发展脉络,并为后续的产学研互动提供建议。本期栏目就《东江上游典型集水区水环境风险控制技术集成与综合示范》(2014ZX07206001)项目进行回顾剖析,为相关从业人员提供后续工作思路。

长江流域典型区河-库水文网络连通综合评估

为合理评估水电建设背景下的河流连通性,选择长江流域高坝大库(金沙江下游)、低坝枢纽(汉江中下游)和山区小水电(景谷)3种典型的河-库系统为研究区。概化典型研究区河-库连通的水文网络模型,将水电站、过渡区、河流汇聚点、闸坝作为重要的网络节点。然后基于网络的水文连通功能、生态环境功能和社会贡献功能构建水文网络连通评估指标体系,利用熵权模糊综合评估方法对典型河-库进行分析。结果表明,高坝大库和低坝枢纽连通性为四级(差),山区小水电连通性为五级(极差)。基于评估结果,针对不同类型的河-库系统给出改善连通性的建议。金沙江下游高坝大库可通过电站的联合调度,对下泄流量进行调控;汉江中下游低坝枢纽应当进一步对流量和水华的相关关系进行研究,确定最佳生态流量,通过对上游水电站进行联合调度,得到抑制水华的下泄流量;景谷河山区小水电需要对网络连通影响较大的小水电实施生态调度,并拆除、改建水库调节能力较差、水力发电效率较低的小水电,改善河网连通状态。

渭-库河绿洲种棉土壤pH与微量元素的相关性分析

为了调整微量元素在种植棉花的土壤中的含量,以及提高施肥的精度,最终达到保护环境质量和农业资源的目的。笔者通过GPS野外定位、量取样品、分析样品等步骤,获取土壤属性数据。运用相关分析模块和统计分析模块,将渭-库河绿洲的种植棉花的土壤作为研究对象,分别分析了土壤中的有机质和p H与四种微量元素之间的相关性特征。结果表明:该研究区中的土壤有机质与有效铁和有效铜呈极显著负相关关系,相关系数分别为-0.557和-0.458,而与有效锰和有效锌之间的相关性不明显,均没有达到显著水平。土壤pH与有效锰呈极显著负相关关系,相关系数为-0.406,与有效锌呈显著负相关,相关系数为-0.274。在生产过程中,应该根据研究区土壤的性质,在合理使用有机肥的同时,适当调节土壤酸碱度,平衡作物中的营养物质,有利于各种作物对微量元素的吸收,从而提高农作物的产量以及质量,保证西北干旱区农业生产的可持续发展。

渭-库河绿洲植棉土壤有机质及盐分之间的相关性分析

[目的]为了实现提高施肥的精度,减少浪费和保护农业资源和环境质量。[方法]在野外取样、GPS定位、样品分析的基础上,获取土壤样品的理化性质等监测数据。在SPSS和GS＋的支持下,运用统计分析、相关分析等方法,以渭-库河绿洲植棉土研究对象,分析耕层土壤有机质现状及其与盐分之间的相关特性。[结果]渭-库河绿洲植棉土有机质平均含量为15.8117.65 g/kg,盐分为3.173.42 g/kg;有机质的变异系数介于13.87%16.19%,盐分的变异系数介于57.10%61.99%;有机质与盐分离子在各个土层中相关特征不一,其在中层土壤中与Mg2＋具有显著性负相关;空间自相关分析表明,有机质的空间结构优于全盐,且二者不论在哪个土层,各自的空间相关性差异不大。[结论]研究区植棉土壤不同土层有机质含量在表层、中层、底层其变异系数依次为16.19%、13.87%、14.28%,表层有机质变异强度最大,底层次之,中层有机质变异最小。盐离子在各个土层变异系数有差异,没有明显特征规律。有机质与HCO3-、Cl-、SO2-4、Ca2＋、K＋＋Na＋等盐离子在表层、中层均具有不同程度的相关特征,但相关性不明显。在表层、中层、底层土壤中有机质含量依次为8.58%、6.29%、6.09%,具有递减趋势特征;盐分在土壤表层、中层、底层的含量依次为3.32、3.42、3.21 g/k,各土层盐分的含量相差甚小,与土壤层次的相关性不明显。有机质的分维数大小排列为中层〉底层〉表层。不同土壤层级中全盐的空间分维数依次是底层〉表层〉中层。

渭-库河绿洲植棉土壤表层养分空间分布特征分析

以渭干河-库车河三角洲绿洲种棉土壤表层养分及其空间分布特征作为主要研究对象,对各养分元素之间进行相关性分析,研究优化调节土壤养分与作物生长的关系,为合理利用土壤养分资源,制定精确的施肥管理措施等方面提供科学依据。采用统计学,地统计学和空间分析方法,在SPSS20.0和surfer8.0软件的支持下,研究植棉土壤养分中的有机质,全氮,碱解氮,有效磷,缓效钾,速效钾等养分元素之间进行相关性分析和正态分布的检验。研究结果表明:(1)从各养分元素的相关性特征来看库车县的植棉土壤中有机质和全氮、碱解氮,全氮和碱解氮都在0.01相关性水平上呈极显著正相关;沙雅县地区的全氮和有效磷在0.05水平上呈显著正相关,新和县地区的缓效钾和速效钾在0.01水平上呈极显著正相关。(2)研究区植棉土壤p H偏碱性,有机质、全氮、速效钾处于很丰富的状态;碱解氮在属于缺乏;有效磷在该研究区中等;缓效钾丰富。(3)从6种养分元素的正态分布特征来看在3个县的植棉土壤中的都服从正态分布。(4)从研究区6种养分元素的空间分布特征来看:碱解氮在中部区域分布比较丰富,并往南和往北逐渐递减的趋势;全氮和有机质比较均匀的分布;速效钾和缓效钾是北部分布比较多而南部较少,呈现由北向南逐渐递减的趋势;速效钾在北部分布较少,而向东南部逐渐递增的趋势。

渭-库河三角洲绿洲农作物需水量分析

对渭一库河三角洲绿洲的主要农作物需水量为研究对象,采用FAO-PM公式,主要农作物不同灌溉方式的需水量进行计算及统计分析。结果显示:主要农作物的传统灌溉总用水量为44.66亿m3,节水灌溉定额总需水量只有为11亿m3,传统灌溉总用水量比节水灌溉定额总需水量大约4.06倍多(33.03亿m3),导致农业用水浪费严重;在渭-库河三角洲绿洲大部分农田仍然采用粗放的大水漫灌和宽河大渠输水的灌溉方式为主,因此,通过采用滴灌、膜上滴灌、膜下滴灌和喷灌等高效节水灌溉技术,可以增加节约水量,并达到农业节水灌溉的目的,这表明可挖节水灌溉潜力相当大。研究对渭一库河三角洲绿洲水资可持续利用提供经验和技术保障,并提出高效节水灌溉的新思路、新方法、新举措,为渭-库河绿洲发展高效节水灌溉农业提供科学依据。

渭-库河绿洲植棉土壤不同土层盐分相关性分析

为渭-库河绿洲植棉土壤盐渍化的治理、改良及合理利用提供一定的理论基础和科学依据,笔者通过筛选渭-库河绿洲植棉土壤上典型的野外考察路线、GPS定点、取样测定,并对植棉土壤不同土层总盐、盐离子含量以及盐离子间进行相关性分析。研究结果表明：植棉土壤不同土层盐分含量分别：0～10 cm 1.555%,10～30 cm 0.454%,30～50 cm 1.082%;p H：0～10 cm p H 8.09,10～30、30～50 cm p H 8.59左右;平均含盐量分别为15.549、4.548、10.821 g/kg。不同深度土层的盐分含量从大到少顺序依次为0～10 cm〉30～50 cm〉10～30 cm,属于盐化土壤。相关性分析结果表明：在研究区植棉土壤不同土层的全盐量、p H、HCO3^-、Cl^-、Ga^2＋、SO4^2-、K^＋＋Na^＋、Mg^2＋之间的相关性基本上呈显著到极显著正相关,尤其是表层土壤中SO4^2-与K^＋＋Na^＋的相关系数达到了0.98,硫酸物在表层土壤积聚强烈,盐分以向上运行为主。

基于河—湖—库水系连通的孔雀河生态输水分析

通过对新疆孔雀河流域水系分布和工程特点的分析,提出了基于河—湖—库水系连通的孔雀河流域抢救胡杨林生态系统的输水方案,并对输水水源、输水路线、输水水量以及输水最佳时间进行了探讨。提出采取跨流域河—河、河—湖、河—库水系连通的方式,提升水资源利用的有效性。当博斯腾湖水位在1 046.5 m以上时,可以从博斯腾湖调水,分西线和东线两条路线,分别向孔雀河中游和下游输生态水,输水量在(0.5～1.0)×108 m^3;而当博斯腾湖处于低水位运行时,建议从塔里木河调水",引塔济孔",由中线和南线两条路线分别向孔雀河中下游和下游输生态水,输水量在1.0×108m^3左右;输水时间以8月底—9月为宜,在输水过程中,需采取一定的工程措施,扩大输水的生态效益。

金沙江梯级大坝运行和三峡水库运行水位增高对长江上游干流寡鳞飘鱼仔鱼丰度和分布的影响

2009年、2012年和2015年在长江上游干流宜宾江段、朱杨江段和木洞江段采集鱼类早期资源,确定寡鳞飘鱼(Pseudolaubuca engraulis (Nichols))仔鱼的发生动态和丰度。金沙江梯级大坝运行前的2009年和2012年,寡鳞飘鱼仔鱼出现高峰开始于5月中旬;运行后的2015年, 6月下旬之前很少有仔鱼出现,高峰开始于7月中旬。梯级大坝低温清水下泄是导致坝下江段寡鳞飘鱼仔鱼发生高峰期推迟的主要原因。与2009年和2012年相比, 2015年寡鳞飘鱼仔鱼丰度在宜宾江段有明显的增加,在朱杨江段略有增加;这表明寡鳞飘鱼种群能够适应大坝运行导致的生境条件的变化。木洞江段2009年至2015年间寡鳞飘鱼仔鱼丰度持续显著升高,可能与该江段位于三峡水库变动回水区相关;调查期间三峡水库运行水位由156 m增至175 m,变动回水区缓流生境为寡鳞飘鱼仔鱼等提供了优良的育幼环境。基于研究结果,我们认为寡鳞飘鱼仔鱼丰度和分布的时空差异是上游梯级大坝和下游三峡水库运行共同作用的结果,反映出广适应性鱼类对建坝水域环境变化的更高的适应能力;同时,我们提出水库上游河流与水库库尾(甚至整个水库)形成的"河-库"复合生态系统可能具有与"河流-泛滥平原"复合生态系统相似的结构和功能,对产漂流性卵鱼类的种群补充具有十分重要的价值。

A GIS-BASED GLACIER INVENTORY FOR THE ANTARCTIC PENINSULA AND THE SOUTH SHETLAND ISLANDS——A FIRST CASE STUDY ON KING GEORGE ISLAND

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)" headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery.This data set will form a first digital baseline study for future glacier monitoring.The presented GIS_based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula.In the database of the glacier inventory topographic information,specific glaciological parameters as well as metadata will be included.The topographic data consists of drainage basin limits,basin areas,altitudinal ranges,perimeters and mean lengths.Glaciological data sets should comprise information on glacier retreat in different periods,glacier velocities,ice thickness and bedrock topography as well as derived parameters.Modelled and measured mass balance parameters could be included as additional data layers.In particular,these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS).Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications,but also other environmental studies on the island will benefit from this standardised remote sensing data sets.Therefore,a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms.Finally,better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950’s onward.

An Ecologically Oriented Operation Strategy for a Multi-Reservoir System： A Case Study of the Middle and Lower Han River Basin, China

Constructing and operating a multi-reservoir system changes the natural flow regime of rivers, and thus imposes adverse impacts on riverine ecosystems. To balance human needs with ecosystem needs, this study proposes an ecologically oriented operation strategy for a multi-reservoir system that integrates environmental flow requirements into the joint operation of a multi-reservoir system in order to main- tain different ecological functions throughout the river. This strategy is a combination of a regular opti-mal operation scheme and a series of real-time ecological operation schemes. During time periods when the incompatibilities between human water needs and ecosystem needs for environmental flows are rel- atively small, the regular optimal operation scheme is implemented in order to maximize multiple human water-use benefits under the constraints of a minimum water-release policy. During time periods when reservoir-induced hydrological alteration imposes significant negative impacts on the river＇s key ecological functions, real-time ecological operation schemes are implemented in order to modify the out- flow from reservoirs to meet the environmental flow requirements of these functions. The practical use of this strategy is demonstrated for the simulation operation of a large-scale multi-reservoir system which located in the middle and lower Han River Basin in China. The results indicate that the real-time ecological operation schemes ensure the environmental flow requirements of the river＇s key ecological functions, and that adverse impacts on human water-use benefits can be compensated for by the regular optimal operation scheme. The ecologically oriented operation strategy for a multi-reservoir system that is proposed in this study enriches the theoretical application of the multi-reservoir system joint operation which considers environmental flow requirements.

Study on the Water Surge Height Line of Landslide Surge of Linear River course Reservoir Based on FLOW-3D

The occurrence and transmission attenuation of surge is always a problem that researchers pay much attention to. The influence of the first wave height of landslide surge and the following transmission attenuation of surge are involved with many factors, which are mainly： landslide water entry angle, river course depth, river course geometrical properties and landslide mass and material, etc.. This thesis is mainly a research on the properties and transmission attenuation rules of landslide surge which is caused by linear narrow river course. Numerical value simulation will be applied in this thesis to discuss about the features and rules of the occurrence and transmission of surge in different landslide water entry angles and under different influences.

Vegetation Influence Investigation of GangnanHuangbizhuang Reservoir Downstream River and Recovery Strategies

The research selected three typical areas for plant investigation, including upper reaches of Gangnan Reservoir, the area between Gangnan and downstream of Huangbizhuang Reservoir, and Huangbizhuang Reservoir. The results showed that affected by water, plant species, species diversity and species richness were all decreasing in varying degrees as the distance with watercourse upper reaches was increasing, but the ratio of Anthropochory plants was growing. The research finally proposed countermeasures, including increasing wetland area, constructing forests and artificial water landscape of Hutuo River and reinforcing watercourse compre- hensive management.

Applications of GSTARS Computer Models for Solving River and Reservoir Sedimentation Problems

GSTARS (Generalized Sediment Transport model for Alluvial River Simulation) is a series of computer models developed by the U.S. Bureau of Reclamation while the author was employed by that agency. The stream tube concept is used in all GSTARS models which allow us to solve one-dimensional equations for each stream tube independently and obtain semi-two-dimensional variation of the hydraulic conditions along and across stream tubes for rivers and reservoirs. Sedi-ment transport, scour, and deposition processes are simulated along each stream tube independently to give us a semi-three-dimensional variation of the bed geometry. Most sediment transport computer models assume that channel width is given and cannot change during the simulation process. GSTARS models apply the theory of minimum stream power to the determination of optimum channel width and channel geometry. The concepts of channel side stability, and active, inactive, and armoring layers are used in all GSTARS models for realistic long-term simulation and prediction of the scour and deposition processes in rivers and reservoirs.GSTARS models have been applied in many countries for solving a wide range of river and reservoir sedimentation problems. Case studies will be used to illustrate the applications of GSTARS computer models.

Maixi River estuary to the Baihua Reservoir in the Maotiao River catchment:phytoplankton community and environmental factors

Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment, southwestern China, to understand phytoplankton community structure and environmental factors. The relationship between phytoplankton community structure and environmental factors including hydrological, meteorological, physical, and chemical variables were explored using multivariate analysis. A total of 81 taxa of phytoplankton were identified, which were mainly composed of chlorophyta, bacillariophyta, and cyanobacteria. The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring. The abundance of phytoplankton ranged from 0.24~ 104 cells/L to 33.45x 106 cells/L, with the minimum occurring during February 2010 and the maximum during July 2009. The phytoplankton community was dominated mainly by cyanobacteria from April to September, and by bacillariophyta and pyrrophyta from October to March. Canonical correspondence analysis showed that temperature, pH values, and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary. Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values, while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.

Spatial distribution,sources and ecological risk assessment of heavy metals in Shenjia River watershed of the Three Gorges Reservoir Area

Surface soil/sediment samples were collected from the Water-Level Fluctuation Zone(WLFZ), cultivated land and forest land at 50 different grid points from Shenjia watershed, the Three Gorges Reservoir area in August 2013. The spatial distribution, sources and ecological risk assessment for Arsenic(As), Cadmium(Cd),Chromium(Cr), Copper(Cu), Nickel(Ni), Lead(Pb)and Zinc(Zn) were analyzed in this study. The results showed all tested metals had similar distribution patterns except Ni and Cr, with areas of high concentrations distributed in the southwest(WLFZ and watershed outlet) of the study area. Ni and Cr,which were highly positively correlated and present in high concentrations, were primarily distributed in the south and middle zones of the study area. Lower concentration areas of all metals were uniformly distributed west of the high-elevation zones and forest land. Factor analysis(FA) and factor analysismultiple linear regression(FA-MLR) showed that the major sources of Cd were fertilizer and traffic sources,which together accounted for 87% of Cd. As, Zn and Cu levels were primarily supplied by industrial and domestic sources, accounting for 76% of As, 75% of Cu and 67% of Zn. Surface soils/sediments of the study watershed contaminated by Cd represent a high ecological risk, whereas other metals represent low ecological risks. The potential ecological risk index(PERI) analysis indicated that it had a low(widerange) ecological risk and a moderate(small-range)ecological risk primarily distributed in the outlet of the study watershed. Fertilizers and traffic are the primary sources of Cd pollution, which should be more closely controlled for the purposes of water quality and ecological conservation.

Efficiency and mechanism of pretreatment on water supply in reservoirs of Yellow River by subsurface constructed wetlands

In order to improve the source water quality of drinking water and mitigate the load of drinking water treatment plant, a pilot test was conducted with integrated horizontal flow constructed wetlands to pretreat the water supply in the reservoirs of Yellow River. Resuhs show that under the hydraulic loading rate of 4 m^3/（ m^2 · d）, the average removal rates of chemical oxygen demand （COD）, total nitrogen （TN）, ammonium nitrogen （ NH4 ^＋ - N）, nitrate nitrogen （ NO3 ^- - N）, nitrite - nitrogen （ NO2^ - - N） and total phosphorus （TP） in the horizontal flow constructed wetlands are 49. 68% , 53.01%, 48.48%, 53.61% , 62. 57% and 49. 56%, re- spectively. The study on purifying mechanism of the constructed wetlands indicates that the disposal of contamination by subsurface wetlands is the combined actions of physical chemistry, plants and microorganism.

The analysis on reservoir sediment deposition and downstream river channel scouring after impoundment and operation of TGP

According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research results achieved in the demonstration stage.It is indicated through analysis that the reservoir sediment deposition and downstream river channel scouring during 8-year impoundment and operation are still within the original forecast,so the original forecasting results are feasible.The further observation and comparison should be conducted because the comparison between the observed data and the original forecast is not so sufficient in time and the prototype observation and related research work should be strengthened in the future.

Response of the distributary channel of the Huanghe River estuary to water and sediment discharge regulation in 2007

The water and sediment discharge regulation （WSDR） project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe （Yellow） River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of ＂To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment＂.