Modeling the phosphorus retention of the Kis-Balaton upper reservoir

The Kis-Balaton reservoir system, consisting of the upper and lower reservoirs, is located near to the mouth of the Zala River. It was established for the protection of Lake Balaton against high nutrient loads. In accordance with the original plan prepared at the end of 70s the aim was that before entering the lake, nutrients - primarily phosphorus - will be removed by macrophytes. The Upper Reservoir started to operate in 1985. In contrast to the predictions, it became an open lake dominated by algae. Until 1991 about 50`90 of the external phosphorus load has been removed yearly. However, the retention efficiency has decreased considerably after reduction of the external load upon phosphorus removal at the wastewater treatment plant of the largest town of the Zala catchment. This observation can be explained by the increased contribution of the internal loading. To analyze the phosphorus removal mechanisms and to understand the behavior of the sediment, different water quality models were applied. The results show that the P retention is characterized by different processes acting spatially differently. Essentially, abiotic processes like settling of inorganic particulate P and the adsorption of dissolved inorganic P are responsible for the P retention in the reservoir, mostly in the neck of the Upper Reservoir. Simple models indicated that the internal loading increased after the external load reduction. In fact, it was not that the internal loading increased, but the adsorption decreased.     

RCP情景下都柳江上游气候变化及径流响应分析

建立都柳江上游三水源新安江月水文模型,根据1968-2004年历史降雨、蒸发及径流数据运用遗传算法来率定和优选敏感参数,使用降尺度GCM数据驱动模型得到不同RCP情景下的流域未来月平均径流,并通过线性拟合方法分析都柳江上游未来气象要素及模拟径流过程。结果表明:2020-2099年都柳江年平均降雨基本处于稳定状态,年平均气温和蒸发呈波动增长,局部短时段下降。流域径流流量总体低于历史平均值,年际间波动降低,年内分布不均,主要集中在5-10月份。     

Methods to quantify and identify the sources of uncertainty for river basin water quality models.

Worldwide, the application of river basin water quality models is increasing, often imposed by law. It is, thus, important to know the degree of uncertainty associated with these models and their application to a specific watershed. These uncertainties lead to errors that are revealed when model outputs are compared to observations. Such uncertainty is typically described by calculating the residuals. However, residuals should not be seen as an estimate of total uncertainty, since through the calibration process, the residuals may be reduced by over-adjustment to the data, which is typically the case for over-parameterised models. Over-adjustment during a calibration period can also lead to highly biased results when the model is applied to other periods or environmental conditions. The total model uncertainties are, therefore, assessed by four components: the sum of the squares of the residuals (SSQ), parameter uncertainties (that can be ignored when their error is much smaller than SSQ), input data uncertainties, and an additional predictive uncertainty that is expressed when the model appears to be biased when it is applied for data other than the data used for calibration. The sources are ranked according to a quantification criterion (magnitude) as well as an identification criterion that depends on the number of observations that are covered by the confidence region. This approach is illustrated with SWAT2003 simulations for flow and sediment of Honey Creek, a tributary of the Sandusky River basin (Ohio). The results show the dominance of the model uncertainty. The input data uncertainty is less important.     

Rainfall-runoff modelling of water resources in the upper Senegal River basin

The streamflow series for the upstream basin of the Senegal River is marked by considerable gaps. The objective of this article is to simulate and extend hydrological data, using the GR2M rainfall-runoff model. A sensitivity analysis of the model to rainfall and water holding capacity input data was performed. This analysis was performed after calculating catchment rainfall, mean potential evapotranspiration, and maximum, minimum and mean water holding capacity. The best combination of input data was chosen by catchment based on the Nash-Sutcliffe criterion. Then cross calibration-validation tests were performed, using the selected input data to choose model parameter sets.     

黄河上游降水变化分析

黄河上游是黄河流域重要的水源涵养区,径流占流域多年平均(1956—2000年)总径流的62%,降水变化不仅是水源的主要影响因素,也关系到涵养能力的变化。本文利用黄河上游43个气象站1960—2021年逐日降水系列数据,基于小波分析划分周期,采用Mann-Kendall检验法、距平法、频率曲线法等对上游区降水变化进行分析,结果表明：(1)黄河上游降水可划分出1963—1981年、1981—1999年、1999—2018年三个明显的周期;(2)1960—2021年年降水量以4.9 mm/10a的趋势增加,三个周期时段内年降水量的倾向率分别为-0.9 mm/10a,-1.0 mm/10a,46mm/10a;(3)1960—2021年年降水量距平百分率在-15%～15%的正常年份占比74%,距平百分率在-30%～-15%的轻旱年份和15%～30%的轻涝年份分别占比15%和8%;距平百分率在30%～40%的中涝年份占3%,旱涝年份基本发生在1963—1981年、1999—2018年两个周期;(4)三个周期时段日降水量具有差异的主要是频率小于10%的降水,且随海拔变化有差异,表现为1999—2018年玛沁站25～45.4 mm/d降水量比以往增强,1999—2018年临夏站20～50 mm/d降水量比以往增强,1963—1981年乌审召站50～65 mm/d降水量比以往增强。     

Modeling phosphorus reduction strategies from the international St. Clair-Detroit River system watershed

Nutrient loading from nonpoint sources has degraded water quality in large water bodies globally. The water quality of Lake Erie, the most productive of the Laurentian Great Lakes bordering the United States and Canada, is influenced by phosphorus loads from the Detroit River that drains an almost 19,000 km² international watershed. We used the Soil and Water Assessment Tool (SWAT) to evaluate a range of management practices to potentially reduce total phosphorus (TP) and dissolved reactive phosphorus (DRP) loads. Scenarios included both single practices and bundles of multiple practices. Single practice scenarios included fertilizer rate reduction (Rate) and sub-surface placement (PL), filter strips (FL), grassed waterways, cover crops (CC), wetlands (WT), controlled drainage, and changes in tillage practices. Bundle scenarios included combinations of Rate, PL, FL, CC, and WT with three adoption strategies: application on all applicable areas, on 55% of randomly selected applicable areas, and on 55% of high phosphorus yielding applicable areas. Results showed that among the single practice scenarios, FL, WT, PL, CC, and Rate performed well in reducing both TP and DRP loss from agricultural dominated sub-watersheds. Over all, the CC, FL, WT bundle performed best, followed by the CC, PL, WT bundle, reducing the load up to 80% and 70%, respectively, with 100% implementation. However, targeting high phosphorus yielding areas performed nearly as well as 100% implementation. Results from this work suggest that there are potential pathways for phosphorus load reduction, but extensive implementation of multiple practices is required.     

温榆河上游流域WDHM模型的原理及建立

针对北京市温榆河上游流域的下垫面条件,采用数学物理方程,建立了机理性的分布式水文模型WDHM,描述次降雨条件下的植被截留、土壤入渗、地表产汇流及河道汇流等水文过程,并用1998年和2000年的2场较大洪水进行了模型的参数率定和检验.     

Ecological changes and the drivers in the Nu River basin (upper Salween)

The Nu-Salween River is one of the most important international rivers in Southeast Asia. Ecological changes in the Nu River in China are of concern given China's increasing development. This paper uses a great deal of data to analyse the ecological changes of the Nu River basin over 40 years. Key conclusions are: policies were the primary driver of ecological changes; population growth was the secondary driver, leading to an increase in the sown area of 29.88%; in 1968–2000, sediment load showed an obvious increasing tend, and it was mainly influenced by natural elements first, then by human activities second.     

基于AWRI指数的汉江上游流域水资源量评估

为了科学评价汉江上游水资源量,提出了一个能够综合反映流域水资源量的指数——AWRI(Aggregate Water Resource Index)。该指数以流域月降水量、蒸发量、平均径流量以及水库平均蓄水量作为输入变量,运用主成分分析法(PCA)分别对每个月份系列进行计算,经标准化第一主成分分析计算后即可得到水资源量。在此基础上,对汉江流域上游进行了AWRI计算与分析。分析结果表明:AWRI指数综合考虑了气象、水文、人为因素对水资源量的影响,能够较全面和准确地反映水资源量的年际变化情况,有利于对流域水资源量改变情况进行评估。     

黄河上中游流域泥沙优化配置研究

针对流域水土流失的灾害性、泥沙利用现状及泥沙优化配置的必要性，基于大系统分解-协调思想的流域泥沙优化配置原理与流域各子系统的泥沙多目标优化配置方法，构建了流域泥沙优化配置理论框架。进而建立了黄河上中游流域泥沙优化配置数学模型，该模型包括相互联系的各子系统、各分区和大系统三级泥沙优化配置数学模型，开展了不同水沙条件下黄河上中游流域泥沙优化配置方案计算，对计算结果进行了评价并提出了建议方案，为黄河上中游流域泥沙的科学治理提供了参考依据。     

Intrinsic and extrinsic sources of phosphorus loading into the Nyando River,Kenya

The Nyando River supports a large human population and an enriched biodiversity. The basin has undergone extreme modification over the last century through changes in hydrological changes and land‐use activities. The impacts of the changes have severely shifted the ecology of the river from desirable to less desirable. Of all the major rivers draining into Lake Victoria‐Kenya, the Nyando River is consistently the most turbid and exhibits the greatest phosphorus load. The present study investigated the present limnological status and sources of phosphorus loads between 2015 and 2016 through water and sediment sampling during high and low flow regimes. The samples were analysed for various phosphorus fractions, including soluble reactive phosphorus (SRP), total phosphorus in water (TP_w), non‐apatite inorganic phosphorus (NAIP), apatite phosphorus (AP), inorganic phosphorus (IP), organic phosphorus (OP), total phosphorus in sediments (TP_s) and elemental compositions. The measured SRP and TP_w concentrations indicated hypertrophic conditions, with means for both high and low flows ranging from 79.3 to 165.7 μg P/L, and 200.0 to 243.9 μg P/L, respectively. The AP concentrations were high, with mean measurements for high and low flows being 766.9 and 790.5 mg/kg, respectively. The sources of high phosphorus loads were established to be both natural and anthropogenic, with major drivers being the industrial establishments along the river basin. Erosion of the catchment phosphorus‐enriched carbonatite rocks and river banks also contributed significant phosphorus loads. Enhanced effluent treatment, quarry dust containment, improved forest cover and regeneration of riverine buffer strips are recommended to restore the river's ecosystems.     

黄河上中游流域泥沙优化配置研究

针对流域水土流失的灾害性、泥沙利用现状及泥沙优化配置的必要性,基于大系统分解-协调思想的流域泥沙优化配置原理与流域各子系统的泥沙多目标优化配置方法,构建了流域泥沙优化配置理论框架。进而建立了黄河上中游流域泥沙优化配置数学模型,该模型包括相互联系的各子系统、各分区和大系统三级泥沙优化配置数学模型,开展了不同水沙条件的黄河上中游流域泥沙优化配置方案计算,对计算结果进行了评价并提出了建议方案,为黄河上中游流域泥沙的科学治理提供了参考依据。     

Drainage basin security of hazardous chemical fluxe in the Yodo River basin.

The Yodo River basin consists of three major tributary basins (and other small river basins) namely Uji, Katsura and Kizu, which overlap respectively Shiga, Kvoto and Nara prefectures' administrative areas. Lake Biwa, the largest lake in Japan, drains water through the Uji river. The water quality of the lake, in terms of BOD, continuously improved over the last decade. However, the quality in terms of COD did not show any improvement in spite of a large amount of infrastructure finance being introduced. Eutrophication of the lake still continues, showing no improvement in the nitrogen concentration level. Non-point as well as point source control is not strong enough. There is a gap between BOD and COD evaluations of the lake water quality. Hazardous chemical fluxes are estimated based upon PRTR reports of Japan (2001). PCBs are still discharged into the lake, although the report of Shiga Prefecture showed zero discharge. Dace fish monitoring clearly showed that PCB contamination of the fish had not changed since the 1980s in spite of a ban on use and production of PCBs in the 1970s. There is still leakage of PCBs into the lake. The major exposure of dioxins to Japanese is fish rather than meat and eggs. The risk of water contamination must take into consideration not only drinking water safety but also ecological magnification of food chains in water. The ecological health aspect of hazardous chemicals is also important, such as organotins with imposex of sea snails. Finally, public participation in hazardous chemical management is very important using the method of risk communication based upon the annual report of PRTR in Japan.     

多模式下泾河上游流域未来降水变化预估

利用站点实测资料、GCMs 月数据对 GCMs 进行秩评分评估排序, 从 21 种 GCMs 模式优选出的 6 种 GCM模式的日数据、6 种 GCM 集成的气候模式、站点实测资料和 NCEP 再分析资料构建统计降尺度模型 SDSM, 预估泾河上游流域的未来降水变化。结果表明: 构建的降尺度模型对降水模拟较为可靠, 率定期各模式决定系数 R2 为 0.228~ 0.324, 标准误差为 0.354~ 0.450, 率定期和验证期模拟月均降水与实测值年内分布相近。在降尺度性能评价中集成模式表现最好。在 RCP 4.5 情景下, 泾河上游流域未来降水大多数模式和集成模式呈增加趋势, 到 2030 年泾河上游流域降水量将增加 4.8% , 且当地的春季雨量会增加, 夏季雨量会减少。     

永定河上游环境变化和水资源演变研究进展

在回顾文献研究进展的基础上,对永定河上游流域气候变化、土地利用变化及水资源量质演变的特征进行梳理和总结,并揭示其驱动因素.分析指出:永定河上游流域气温突变型升高,最低气温及冬季气温上升显著;年均降水量呈现不显著下降趋势,夏季降水下降趋势明显;潜在蒸散发和实际蒸散发并未随温度升高而升高,且流域存在一定的"蒸发悖论"现象....     

永定河上游人类活动对降雨径流关系的影响

通过水资源开发利用及水土保持综合治理，永宁河上游流域下垫面条件不断改变，从而影响了产汇流条件和官厅水库入库径流；利用新资源延长官厅水库径流系列，建立流域降雨径流关系，定性分析人类活动对官厅水库年降雨径流关系的影响，为流域水资源开发利用和综合治理研究提供依据。     

不确定条件下的多水源联合供水调度模型

本文针对城市供水调度系统中存在的不确定性与复杂性,运用区间两阶段随机规划的方法,建立了多水源联合供水调度的优化模型。该模型以供水调度系统成本最小为目标函数,引入概率分布及区间数表示不确定性,模拟了地表水源、地下水源、外来水源等多种水源联合供水过程,并对多种水源的调水目标进行优化。以区间形式给出优化结果,为决策者提供宽裕的决策空间。利用该方法,可充分考虑系统中不确定因素对系统成本的影响,更真实的反映多水源联合供水系统的实际情况。     

不同气候情景下和田河上游径流变化

位于内陆的和田绿洲,其水资源主要来自上游山区,山地径流的变化将直接影响社会经济活动。基于此,对和田河流域上游1980—2015年的降水、温度、径流的变化趋势以及降水、温度对径流的影响进行分析,构建相应的soil and water assessment tool（SWAT）模型,结合气候模式对未来6种气候变化情景下的径流进行预测。结果表明：1980—2015年和田河流域上游年均气温和年降水的变化率分别为0.31 ℃/10 a和16.5 mm/10 a,均呈显著增加趋势,年径流也呈上升趋势;以2009—2011年为基准期,若和田河上游降水量分别增加12.5%、10%和减少10%,则其径流量将分别增加8.19%、6.45%和减少6.23%;若和田上游流域温度分别增加0.3 ℃、1 ℃和2 ℃,则和田河径流量将分别增加1.96%、7.74%和12.99%;预设的6种情景径流量均呈现增加趋势,其中2021—2030年HADG_RCP8.5情景下径流量最小,为51.25亿m3/a;2031—2040年,BCC_RCP4.5情景下径流量最小,为53.06亿m3/a。所得结果可以为当地水资源调配提供理论支撑。     

Application of uncertainty and sensitivity analysis in river basin management.

Considering uncertainty in the decision-making process in river basin management is important because uncertainty is regarded as one of the main obstacles to sound decision-making. In case of high uncertainty, the risks of making a wrong decision could be quite high, which may have severe consequences. This paper applies a screening sensitivity analysis method, the Morris method, to investigate the propagation of uncertainty from factors in a flood damage model into the model outputs and explores the importance of factors based on the sensitivity analysis. Uncertainty reduction in the most influential factors identified by the Morris method is proposed as a means to reduce the uncertainty in model outputs. In this way the risks of making a wrong decision could be reduced. The results in this paper show that the Morris method is an efficient approach to help reduce the uncertainty in model outputs.     

多GCM模型集合下开都河流域未来气候变化预估

基于逐步聚类分析的统计降尺度模型(SCADS模型),在多GCM模型集合的9个大尺度气象变量与开都河流域6个气象变量之间,建立统计降尺度关系,并进行开都河流域未来气候变化的预估。结果表明,SCADS模型生成的开都河流域各气象变量的模拟值与实测值拟合较好。各气象变量在率定期(1961年-1990年)和验证期(1991年-1999年)的NSE系数均大于0.55,精度较高。此外,利用SCADS模型进行开都河流域各气象变量的预估。发现在三个不同时期内(2011年-2040年,2041年-2070年和2071年-2100年),月均气温升高,月均蒸发量、降水量、日照时数增加,月均相对湿度升高。