Long-term Circulation and Eutrophication Model for Tolo Harbour,Hong Kong

Since the early 1980s excessive discharges of organic waste into Tolo Harbour have created serious problems through nutrient enrichment. A number of eutrophication related problems have been reported which incurred financial losses of billions of dollars and serious ecological imbalance. This work addresses the development, verification and application of a water quality model to synthesize the available large database of water quality and to study water quality management issues of Tolo Harbour. Since detrimental water quality problems usually occur during summer when there is stratification and the water temperature is high, the tidally-averaged hydrodynamics and the relative contribution of gravitational circulation and tidal exchanges in Tolo Harbour have been studied. Gravitational circulation is found to be the dominant mixing process for most of the year, accounting for 70 percent of the mixing. A simple and tractable predictive two-layer mass transport and diagenetic dynamic eutrophication model has been developed. The model computes daily variation of key water quality variables in the water column: algal biomass, dissolved oxygen, organic-nitrogen, ammonium-nitrogen, nitrate-nitrogen, and carboneous oxygen demand. In addition, to study the response and impact of the seabed to the overall eutrophication process a sediment sub-model is developed. The diagenetic sediment sub-model computes explicitly the amount of nutrient recycled and the sediment oxygen demand exerted on the water column. The calibrated model has been validated against a 20 year water quality data base under a wide range of hydro-meteorological and environmental conditions. Both spatial and seasonal variation of observed water quality variables are reproduced. The verified model shows that a significant reduction of total nitrogen loading would be required to meet the water quality objectives, with a recovery time of three months for water column and more than two years for sediment.     

基于经验频率曲线的湖泊富营养化随机评价方法及其验证

本文提出了基于经验频率曲线的湖泊富营养化随机评价方法.该法通过建立水体富营养化评价标准中各项水质指标和评价级别的经验频率曲线,推求实际水体各项水质指标的经验频率,并采用加权平均法推求湖泊富营养化评价级别的经验频率,从而得出湖泊富营养化的评价级别,具有方法简单、图形直观、计算工作量小的特点.经全国30个湖库湖泊实测水质资料的验证,随机评价方法与模糊评价方法和灰色评价方法的计算精度相当.     

基于长时间序列乌梁素海水环境变化趋势及生态补水等关键驱动因子分析(2011—2020年)

基于2011—2020年乌梁素海水质监测数据,将综合营养指数法、PCA排序法和ArcGIS克里金插值法有机结合,综合评价2011—2020年乌梁素海水体富营养化程度年际时空变化特征,厘清引起水体富营养化发生变化的关键性驱动因子。研究结果表明:(1)乌梁素海水体总磷和总氮的峰值出现在平水期,氨氮的峰值在枯水期,COD_Mn的峰值在丰水期,水质整体以地表Ⅲ类水为主。(2)2011—2020年湖体水质经历了由轻度富营养-中营养-轻度富营养-中营养的变化过程,综合营养状态指数在60～70(中度富营养)的湖区面积占比由21.49%逐渐消失,综合营养状态指数在30～50(中营养)的湖区面积占比由23.84%扩增到44.87%。(3)乌梁素海生态补水量与总氮、总磷、COD_Mn和综合营养状态指数呈负相关,是影响湖泊水体营养化的另一个关键性驱动因子。     

An unsteady three-dimensional eutrophication model in Tolo harbour, Hong Kong

The eutrophication phenomenon often leads to undesirable water quality. This paper delineates an unsteady three-dimensional finite difference numerical model for eutrophication dynamics in the coastal waters of Tolo harbour, Hong Kong, employing the numerically generated, boundary-fitted, orthogonal curvilinear grid system as well as a grid “block” technique. It models the transport and interaction of nine water quality constituents. Adjustments of values of some kinetic coefficients in the model are effected through calibration with field data. It is demonstrated that the model can reasonably reproduce the interactions amongst all the water quality constituents, the eutrophication processes and, in particular, the featured bottom water anoxic condition during the summer in Tolo harbour.     

Zum Sauerstoffhaushalt der Gewässer der Feldberger Seenplatte an Hand ausgewählter sommerlicher Tiefenprofile seit 1924 und 1962 Teil 3: Scharteisen,Wasch-See,Dolgener See

This paper presents the depth profiles of 1951 … 1980 for the Scharteisen, the investigations of the last years for the Wasch lake and the Dolgen lake, for the oxygen regime with the representation of the oxygen concentration, transparency, water temperature and the upper limit of the occurrence of hydrogen sulphide. The profiles demonstrate the eutrophication having occurred for the Scharteisen and the present state for the three lakes. The general situation of the drainage areas and the causes to be derived from it concerning changes of the water quality as well as possible measures and aims of sanitations are discussed. Also the most important data are given on the hydrography of these waters and on their utilization for obtaining drinking water and by fishery up to now.     

2016—2020年长江中游典型湖泊水质和富营养化演变特征及其驱动因素

“十三五”时期,长江流域水环境质量改善明显,但湖泊水质和富营养化状况改善滞后.长江中游作为我国淡水湖泊集中分布区域之一,部分湖泊存在水环境质量恶化和富营养化加重问题.本文以长江中游区域国家开展监测的洪湖、斧头湖、梁子湖、大通湖、洞庭湖和鄱阳湖这6个典型湖泊为研究对象,科学评价其2016-2020年水质和富营养化时空变化特征及关键驱动因素,探讨其成因及治理对策.结果表明,“十三五”时期长江中游湖泊水质和富营养化程度存在较大差异,与2016年相比,2020年大通湖水质改善最为明显,梁子湖水质变差,总磷是影响长江中游湖泊水质类别的主要因子;洪湖富营养程度恶化最为严重,斧头湖次之,TLI(SD)对长江中游湖泊富营养化评价贡献最大.目前长江中游湖泊呈有机污染加重和叶绿素。浓度升高现象,洪湖、斧头湖和梁子湖主要与氮、磷营养盐浓度升高有关,而大通湖、洞庭湖和鄱阳湖受水文过程、流域纳污量和湖泊管理等非营养盐因素影响较大.总氮和总磷仍然是影响“十三五”时期长江中游湖泊水质和富营养化的最主要驱动力,且各湖泊总氮和总磷浓度变化均具有较强正相关性,建议开展河湖氮、磷标准衔接工作,提出河湖氮、磷标准限值或考核目...     

湖北长湖富营养化状况及时空变化(2012-2013年)

为评估长湖水体富营养化程度,2012-2013年分4个季度对全湖区20个采样点的物理、化学和生物要素进行监测,在评价水质现状的基础上采用综合营养状况指数法和浮游植物细胞丰度指数法综合评价水体营养状况,并应用典型相关分析(CCA)方法揭示水体富营养化状况与湖泊理化要素之间的典型相关性.结果显示:4个季节长湖全湖区的水质均处于地表水IV类~劣V类水标准;综合营养状态指数值在49.54~82.55之间,浮游植物细胞丰度在2.88×106~61.73×106cells/L之间,均显示其处于富营养化状态;长湖富营养化状况的分布呈现一定的时空差异性;CCA分析显示,长湖理化要素变量可解释68.6%的水体富营养化状况变量的变异,影响其富营养化状况的主要理化因素有水体总磷、总氮、溶解氧、亚硝态氮、硝态氮浓度,水深和沉积物总磷、总氮含量.长湖水体富营养化主要是由于外源的磷污染,其次是氮污染,富营养化最严重的夏、秋季浮游植物的生长主要受氮营养限制,而冬、春季则部分受磷营养限制,部分属于过渡类型.因此,建议大力削减围网/围栏养殖量,同时考虑结合水生植物栽种等生态工程建设措施以降低长湖水体发生严重富营养化的风险,并进一步改善长湖的水质现状.     

2015-2019年武汉市湖泊水质时空变化

为探究“十三五”期间武汉市湖泊水质变化特征及规律,分析当前武汉市湖泊水环境的主要问题及成因,为武汉市水生态环境保护“十四五”规划提供科学支撑,以武汉市166个湖泊为研究对象,根据武汉市环境监测中心2015-2019年对各个湖泊的监测数据,采用水质综合污染指数、富营养化状态评价、动态度分析等方法,对武汉市湖泊水环境进行综合评价.结果表明：1）2015-2019年武汉市湖泊水质总体好转,2019年全市湖泊综合污染指数较2015年下降7.74%,多数湖泊营养状态呈现稳中向好趋势,但湖泊水质较难实现持续改善.2）武汉市湖泊主要超标污染物总磷、氨氮、化学需氧量和高锰酸盐指数平均质量浓度在2015-2019年间均呈下降趋势,但2019年有47%湖泊总磷浓度劣于Ⅳ类评价标准,磷元素是制约湖泊水质的主要因素.3）2015-2019年武汉市中心城区湖泊综合污染指数下降,湖泊富营养化状态好转,但青山北湖、南湖等湖泊综合污染指数较高,排口排污、底泥内源污染是影响中心城区湖泊水质的主要因素.新城区湖泊水质改善仍面临一定压力,东西湖水系重度富营养化湖泊数量增多,后湖水系湖泊综合污染指数上升,农业面源、工业生产对新城区湖泊水质影响较大,湖泊破碎化导致的自净能力降低也是影响湖泊水质的重要因素.     

Optimum operation of restoration techniques for eutrophic water bodies

Operating rules have been applied in water resources management for a long time in order to control and supply a requiredquantity (volume) of water. The operating rules have to guarantee the optimum management of the reservoir(s). Thequality of the stored water has been satisfactory for the desired utilization up to the sixties. Due to the deterioration of reservoir water quality through human impacts, however, increased attention had to be paid since. Eutrophication of stagnant waters is still an unsolved problem. Through means of various restoration techniques, i.e., dilution/flushing or hypolimnetic withdrawal, the quality of the stored water can be improved. Continuous operation or appropriate time or depth variant operating rules are required to achieve this goal. The paper presents such rules for long-term operation. They have been established for the first time and can he represented in two or three-dimensional graphs depending on the number of included components (e.g., actual water storage and quality). The quality operating rules take into account the dynamics of the processes in aquatic ecosystems. Simplifications with regard to application and acceptance (e.g., clarity) are developed and tested. The general validity and efficiency of the operating rules have been proved in a case study (a multi-purpose reservoir) and a fictitious lake.     

An application of contingent valuation and decision tree analysis to water quality improvements

This paper applies contingent valuation and decision tree analysis to investigate public preferences for water quality improvements, and in particular reduced eutrophication. Such preferences are important given that the development of EU water quality legislation is imposing significant costs on European economies. Results are reported of a survey undertaken of residents of Århus County, Denmark for water quality improvements in the Randers Fjord. Results demonstrate strong public support for reduced eutrophication and identify key determinants of such support.     

Eutrophication control decision making using EFDC model for Shenzhen Reservoir,China

The three-dimensional hydrodynamic and eutrophication model was implemented based on EFDC to help eutrophication control decision making of Shenzhen Reservoir. Model calibration and validation were conducted with two set of independent observed data in 2009 and 2010–2011. The model represented the hydrodynamic process and the spatial and temporal distribution of water quality well. Subsequently, three eutrophication control scenarios were configured, included removing 100% nutrients from all tributaries, increasing by 50% of water flows, and removing 50% nutrients from Dongjiang. As results shown, the maximum chlorophyll-a concentrations were decreased by 1, 16.4 and 46.3%, the average chlorophyll-a concentrations were decreased by 1.3, 29.8 and 29.9%. Increasing water flows and removing nutrients from Dongjiang can significantly improve water quality and effectively reduce risk of water bloom.     

2006-2017年乌梁素海夏季水体营养状态及影响因子

为探明草型湖泊乌梁素海水体营养状态及演变趋势,明确水体富营养化的关键影响因子,本文采用2006-2017年每年7月份湖泊水质监测数据,利用综合营养指数法评价了湖泊不同区域监测点的水体营养状态,模拟分析了湖泊水体营养状态的演变过程及趋势特征,定性分析了湖泊富营养的关键影响因子.研究结果表明：乌梁素海湖区北部、西部和南部监测点处于轻度富营养状态的极限概率分别为0.588、0.633和0.329,而湖泊的中部和东部监测点处于中营养状态的极限概率分别为0.810和0.536,说明乌梁素海湖区北部、西部和南部区域夏季水体营养状态将呈现向轻度富营养化演变的趋势,而湖区中部和东部区域则呈现向中营养化演变的趋势.水环境因子中水体理化指标对湖泊富营养化起决定性作用,且盐度指标响应概率高达55%,是水体理化指标中第1位影响因子,同时pH值与水深指标也是影响乌梁素海水体富营养化程度的重要因子.     

底泥疏浚能控制湖泊富营养化吗?

世界上许多湖泊面临着严峻的富营养化问题,富营养化湖泊底泥中的营养盐比水体中要丰富得多,因此,人们常把疏浚底泥作为治理富营养化湖泊的一种重要措施,它需要巨大的资金投入,但尚未见在中等以上湖泊中通过疏浚底控制湖泊富营养化的明显实例,分析 浚底泥作为水利工程和航道工程措施有重要效用,其改善水质效果与疏浚方法有关,适当的疏浚可在短期内改善水质,但从月和季以上长期段持,疏浚底泥不是控制湖泊富营营养化的充要条     

湖泊富营养化响应与流域优化调控决策的模型研究进展

湖泊富营养化是全球水环境领域面临的长期挑战,富营养化响应与流域优化决策模型是制定经济和高效调控方案的关键.然而已有的模型研究综述主要集中于模型开发、案例应用、敏感性分析、不确定性分析等单一方面,而缺少针对非线性响应、生态系统长期演变等最新湖泊治理挑战的研究总结.本文对数据驱动的统计模型、因果驱动的机理模型和决策导向的优化模型进行了综述.其中,统计模型包含经典统计、贝叶斯统计和机器学习模型,常用于建立响应关系、时间序列特征分析以及预报预警;机理模型包含流域的水文与污染物输移模拟以及湖泊的水文、水动力、水质、水生态等过程的模拟,用于不同时空尺度的变化过程模拟,其中复杂机理模型的敏感性分析、参数校验、模型不确定性等需要较高的计算成本;优化模型结合机理模型形成“模拟优化”体系,在不确定性条件下衍生出随机、区间优化等多种方法,通过并行计算、简化与替代模型可一定程度上解决计算时间成本的瓶颈.本文识别了湖泊治理面临的挑战,包括:①如何定量表征外源输入的非线性叠加和湖泊氮、磷、藻变化的非均匀性?②如何提高优化调控决策和水质目标的关联与精准性?③如何揭示湖泊生态系统的长期变化轨迹与驱动因素?最后,本文针对这些挑战提出研究展望,主要包括:①基于多源数据融合与机器学习算法以提升湖泊的短期水质预测精度;②以生物量为基础的机理模型与行为驱动的个体模型的升尺度或降尺度耦合以表达多种尺度的物质交互过程;③机器学习算法与机理模型的直接耦合或数据同化以降低模拟误差;④时空尺度各异的多介质模拟模型融合以实现精准和动态的优化调控.     

基于EFDC模型的深圳水库富营养化模拟

基于EFDC模型构建了深圳水库三维水动力和富营养化定量模拟模型.分别用2009年和2010 2011年流量、水位和水质等观测数据对模型进行了校正和验证,准确地反映了深圳水库的水动力和水质变化过程.在此基础上,假定支流污染截排、水库调度和降低东江引水污染负荷3种情景进行深圳水库富营养化数值模拟,3种情景下库中Chl.a峰值浓度分别降低1.0%、16.4%和46.3%,平均浓度分别降低1.3%、29.8%和29.9%.深圳水库具有良好的交换能力,尚未出现水华暴发,但入库营养盐负荷高,存在较大的富营养化风险;在目前沙湾河污水已经截排的基础上再实施支流污染控制,对水质改善和藻类控制作用已不明显;水库调度和削减东江引水污染负荷对深圳水库水质和富营养化改善明显,能够有效降低水华发生的风险.     

太湖富营养化问题及其综合控制对策

On the basis of nine-time current situation investigation for eutrophication of Taihu Lake during 1991-1995, this paper evaluated the trophic levels in the different periods and analyzed the development of the main nutrient content in the nearest 35 years. The results show that the trophic level of Taihu Lake is in the transition state from meso-eutrophic to eutrophic. The eutrophhic and hypereutrophic waters account for 10% or so. The limiting nutrient, P, rises most rapidly, which causes the ratio of N:P to decrease. The increase of P content is still one of the main factors giving rise to the eutrophication of Taihu. LakeSome proposals of comprehensive countermeasure for the eutrophication are put forward. They include the pollution source control of the basin, the littoral multiple management, optimal dispatch of water conservancy facilities, the engineering of helping Taihu Lake with diversion of the Changjiang River, and as well as the setting of the water quality protection and legal system.     

极大螺旋藻铁型超氧物歧化酶的纯化及性质

将待评价样本作为事件,水质级别作为对策,构造局势。通过用效果测度统一计量评价指标,按级别变量特征值确定最优局势,提出了用改性灰色局势决策法综合评价湖泊水体富营养化状况并结合实例说明该决策法评价湖泊水体富营养化,具有客观性和实用性。     

The driving force of basin water resource utilization to lake nutrients

ABSTRACT

Understanding of the effect of basin water resources utilization on lake nutrients is helpful to prevent lake eutrophication and facilitate sustainable water resources management. In this study, a lake basin dualistic water cycle system is established to identify the environmental effect of lake water. Four water utilization indicators were chosen to build a driving relationship with the lake nutrients. Three different trophic lakes in Yunnan Province, China – Dianchi, Erhai and Fuxian – were selected to demonstrate the changes in basin water utilization, runoff, nutrient loads and water-use indicators for the period 2000–2015. In addition, the driving forces of water-use indicators to nutrients (total nitrogen and total phosphorus) were analysed by a general additive model. Finally, an optimized water utilization system for each lake basin is proposed. The research provides a practical tool for water resources and environmental management in lake basins.     

巢湖富营养化的历程、空间分布与治理策略(1984-2013年)

通过文献调研,分析巢湖富营养化的历程及其与合肥市社会、经济与人口发展的关系,同时利用遥感解译和野外调查监测方法分析2012和2013年巢湖主要富营养化指标及蓝藻水华的空间分布特征,并进一步探讨各个阶段湖泊治理措施对巢湖富营养化过程的影响.研究发现:近30年间,1984-1994年是巢湖水质的主要恶化阶段,在1990s中期巢湖的富营养化达到了近30年的峰值,这主要是经济快速发展、污染治理投入有限所致;1995-2007年,巢湖的水质逐步改善,恢复到1980s中期略高的水平,这得益于"九五"和"十五"期间的大量投入,对污、废水进行处理,限制了污染物直接入湖;但是2008年以来,巢湖的水质改善效果并不明显,富营养化维持在较高水平波动,这可能是因为合肥市经济快速发展背景下,原有的污、废水处理后入湖的减排方式已经不能进一步有效削减巢湖的污染负荷.巢湖富营养化在空间分布上呈现西高东低的渐变趋势,这主要是由西部主要入湖河流污染所致.通过对比2012和2013年的空间分布数据发现,2013年主要入湖污染河流河口水质相对2012年均有所好转,其中十五里河河口的好转比南淝河河口明显.综合长期及全湖富营养化水平的变化分析,现阶段巢湖富营养化的治理亟需改变经济发展模式,调整产业结构,实施污废水尾水提标改造、畜禽养殖污染控制和面源污染控制等控源工程,以进一步降低巢湖的富营养化程度.     

Trends in eutrophication research and control

Eutrophication is the natural ageing process of lakes. It is characterized by a geologically slow shift from in-lake biological production driven by allochthonous (external to the water body) loading of nutrients, to production driven by autochthonous (in-lake) processes. This shift typically is accompanied by changes in species and biotic community composition, as an aquatic ecosystem is ultimately transformed into a terrestrial biome. However, this typically slow process can be greatly accelerated by human intervention in the natural biogeochemical cycling of nutrients within a watershed; the resulting cultural eutrophication can create conditions inimical to the continued use of the water body for human-driven economic purposes. Excessive algal and rooted plant growth, degraded water quality, extensive deoxygenation of the bottom water layers and increased fish biomass accompanied by decreased harvest quality, are some features of this process. Following the Second World War, concern with cultural eutrophication achieved an intensity that spurred a significant research effort, culminating in the identification of phosphorus as the single most significant, and controllable, element involved in driving the eutrophication process. During the late 1960s and throughout the 1970s, much effort was devoted to reducing phosphorus in wastewater effluents, primarily in the developed countries of the temperate zone. These efforts generally resulted in the control of eutrophication in these countries, albeit with varying degrees of success. The present effort in the temperature zone, comprising mostly developed nations, has now shifted to the control of diffuse sources of a broader spectrum of contaminants that impact human water use. In the developing countries of the inter-tropical zone, however, rapidly expanding populations, a growing industrial economy and extensive urbanization have only recently reached an intensity at which cultural eutrophication can no longer be ignored. Further, initial attempts at applying temperate zone control measures in this region have been largely unsuccessful. Modification of the temperate zone eutrophication paradigm will be needed, especially to address the differing climatic and hydrological conditions, if cultural eutrophication is to be contained in this region, where eutrophication-related diseases continue to be a primary cause of human distress.