Entropy method for determination of weight of evaluating indicators in fuzzy synthetic evaluation for water quality assessment

Considering the difficulty of fuzzy synthetic evaluation method in calculation of the multiple factors and ignorance of the relationship among evaluating objects, a new weight evaluation process using entropy method was introduced. This improved method for determination of weight of the evaluating indicators was applied in water quality assessment of the Three Gorges reservoir area. The results showed that this method was favorable for fuzzy synthetic evaluation when there were more than one evaluating objects. One calculation was enough for calculating every monitoring point. Compared with the original evaluation method, the method predigested the fuzzy synthetic evaluation process greatly and the evaluation results are more reasonable.

Study on Entropy Weight Coefficient Method and Application for Water Quality Evaluation

In order to evaluate the quality of water environment, the conception of entropy is applied in information science, and the entropy weight model is built to evaluate comprehensively water quality. The indexes weights of water quality are determined by value of entropy. This kind of method is applied on evaluating water quality in the new water to be built. The result shows that the water quality in it which supply water is between grade Ⅲ and Ⅳ, and the result is similar to that of gray related method.

Integrated Analysis of Water Quality in Artificial Fishponds Using WQI and GIS in South-East Sierra Leone

Artificial fishponds play a pivotal role in global aquaculture, serving as a source of livelihood and nourishment for many communities. Ensuring the sustained health and productivity of Fishes in these environments relies heavily on water quality management. This assessment was done to determine the water quality of ten artificial fishponds in the south-eastern part of Sierra Leone using twelve physicochemical factors (pH, BOD, EC, TDS, turbidity, COD, Fe2+, Mg2+, Ca2+, NH3, , and alkalinity) to find out the Water Quality Index (WQI) and spatial distribution of respective parameters. The assessment of artificial fishponds using WQI and Inverse Distant Weighting (IDW) integration represents a relatively underexplored area within the domain of environmental water resources. The WQI was determined using the “Weighted Arithmetic Water Quality Index’’ method. The results of WQI in the study area range from 65.05 to 147.26. Several locations have water quality deemed unsuitable for consumption, while others range from good to very poor. It is essential to address and improve water quality in locations categorized as unsuitable for consumption and very poor to ensure safe and healthy water sources. It was also clear from the calculation that the smaller the mean concentration value of the pH as compared to the ideal value (7), the smaller the WQI value and the better the water quality. To keep the artificial fishpond water in good condition, mass domestic use should be controlled, and draining of surrounding organic matter should be stopped in ponds Bo_001, Kenema_001, and Kenema_002.

An Analysis of Water Environment Factors and an Evaluation of Water Quantity of Liangzi Lake

The experiments of single factor evaluation method, principal component analysis and voronoi area weighting factor method on the sample data of Liangzi Lake in October 2012 combined with the national surface water environment quality standards can get the map of comprehensive water quality distribution by Kriging interpolation. The analysis shows, the grades of comprehensive water quality gained by three methods are all only class III or class IV, and the quality of water is different from east and west that the water quality of east is better. However, the percent of IV class water is higher in the result of single factor evaluation method means class IV is the main grade of water quality. The result of principal component analysis shows the percent of class Ⅲ water is higher than other classes. The result of voronoi area weighting factor method shows the percent of IV class is higher than other classes. CODMn is the main factor that influences the method of singal factor evaluation and reduces the grade of water quality overall. The effect of single factor is reduced by principal component analysis, and the analysis on water quality is more accurate. The voronoi area weighing factor method reduces the effect of single factor and extends the content, can make a comprehensive evaluation on water quality.

Water Quality Index Assessment under Climate Change

Surface water quality may change in the future due to climatic variability as natural processes will most likely be modified by anthropogenic activities. As such, stream temperature is very likely to change as well which will impact on surface water quality and aquatic ecosystem dynamics. The present study focused on improving modelling of surface water quality indices and water quality parameters under various climate change scenarios in relationship with stream temperature. Future climate data were extracted from the Canadian Coupled General Climate Model (CGCM 3.1/ T63) under the greenhouse emission scenarios B1 and A2, as defined by the Intergovernmental Panel on Climate Change (IPCC). This study illustrates the usefulness of the stream temperature models, coupled with Climate Change Scenarios to predict the evolution of future stream water temperature regimes and associated biogeochemical water quality parameters pertaining to drinking water quality. The specific objectives of the present study were to analyze the surface water quality of 15 rivers in New Brunswick (Canada) on the basis of 9 parameters under climate change. A Weighed Method and the Canadian Council of Ministers of the Environment (CCME) Method were used to assess the water quality for each river under present and future climate. The knowledge gained from this study will enable engineers and water resources managers to better understand river thermal regimes and climate change impact on water quality related to Drinking Surface Water.

Construction and Application of Combined Evaluation Model of Regional Water Quality Plan

[Objective] The aim was to study the construction and application of combined evaluation model of regional water quality plan. [Meth- od] By dint of layer analysis, subjective and objective model of entropy evaluation, the water quality plan in Jinghe was evaluated. Combined evalu- ation model based on information entropy were constructed, and considering the single model evaluation result, the optimal water quality plan was selected. [ Result] The combination weight result suggested that COD amount was the most essential indicator in water quality plan and embodied the importance of water environment protection, which met basic objective of environment protection and social, economic effects. Combined evalu- ation indicated that in the sixteen plans, plan 16 was of highest comprehensive evaluation value, and can be considered as optimum water quality plan. [ Conclusion] Combined evaluation model can effectively list the advantages of each evaluation model and improve the dependability of water quality plan, and provided a new research idea for the optimal evaluation of water pollution control plan.

基于熵权TOPSIS的黄河流域甘肃段水资源承载力评价

为评价黄河流域甘肃段水资源承载力,以黄河流域甘肃段4个二级分区为研究对象,初选20个评价指标,利用信息敏感性和相关性分析法剔除敏感性较低和相关性较高的7个指标,最终确定13个评价指标。从系统角度将指标分为水资源、社会、经济、生态环境4个子系统,利用熵权法与TOPSIS模型结合的方法计算综合得分,并利用障碍因子诊断模型分析4个二级分区的水资源承载力障碍因子。结果表明:空间维度上,黄河流域甘肃段水资源承载力存在空间差异性,龙羊峡以上分区水资源承载力最高,龙羊峡—兰州分区与兰州—河口镇分区水资源承载力次之,龙门—三门峡分区水资源承载力最低;时间维度上,除龙羊峡以上分区外其余3个二级分区水资源承载力均有缓慢上升趋势;人均水资源量、产水模数、人均供水量、人口密度、城镇化率及生态环境用水率是影响黄河流域甘肃段水资源承载力的主要障碍因子,建议优化水资源配置、调整用水结构、促使经济发展与水资源承载力相匹配等,以提升及保持黄河流域甘肃段水资源承载力。

河南省引黄受水区农业水资源安全综合评价

农业水资源安全对粮食安全、生态环境和农村经济发展意义重大。为推动区域农业水资源高效利用和可持续发展,综合考虑不确定性和复杂性因素的影响,采用序关系分析法、熵权法、TOPSIS法,选取水资源禀赋、生态环境和水资源利用3个子系统11个指标,构建评价指标体系,评估2022年河南省引黄受水区14个地级市的农业水资源安全状况。结果表明:14个地级市中除开封市为水资源“不安全”等级以及新乡市、鹤壁市、濮阳市为水资源“一般安全”等级外,其他10个地级市均为水资源“较安全”等级,距离“安全”等级还有一定距离。建议采取提升水质、增加可利用水资源量、调整作物种植结构、提高水资源利用效率、实施最严格水资源管理制度等措施,保障河南省引黄受水区农业水资源安全。

基于大型底栖动物完整性指数与综合生物指数的水生态评价

针对不同流域部分生物指数评价标准并不统一的问题,利用熵权法构建综合生物指数(CBI)统一模糊评价标准,同时计算底栖动物完整性指数进行评价结果验证.以2021年秋季和2022年春季东洞庭湖10个监测点的数据为基础,通过对25个候选参数逐步筛选,选出M3(软体动物分类单元数)、M9(耐污类群相对丰度)、M13(BI指数)和M22(Shannon-Wiener指数)4个秋季核心参数以及M6(摇蚊个体相对丰度)、M13、M16(BPI指数)和M24(Margalef指数)4个春季核心参数,采用比值法统一量纲后累加计算底栖动物完整性指数,再对BPI、FBI、Shannon-Wiener、BMWP指数客观定权后计算CBI指数划分出5个状态进行对比,结果表明:B-IBI指数和CBI指数均得出靠近出湖河道点位较为健康,湖体点位多为一般和较差,整体秋季健康状况略好于春季,六门闸附近为极差状态,可能是因为该区域是东洞庭湖的闸口之一,常年关闭导致水体流动性较差,开闸放水后沉积物中的淤泥会释放污染物使得湖区总氮超标,进而影响了大型底栖动物的完整性.CBI指数与B-IBI指数以及COD_(Mn)、TLI(∑)指数等相关分析结果良好,表明利用综合生物指数和底栖动物完整性指数结合能为东洞庭湖的水生态健康评价提供参考.

人民胜利渠灌区水资源安全综合评价

基于灌区水资源安全理论,构建水量、用水效率、生态3个准则层,选取水资源总量、每公顷农田灌溉水量、万元工业增加值用水量、生态用水量占比等10个指标,并依据人民胜利渠灌区2015—2020年社会、自然、经济和水资源等相关数据及统计资料,采用熵权法-层次分析法评价模型,对人民胜利渠灌区水资源安全进行综合评价。结果表明:2015年、2016年和2020年人民胜利渠灌区水资源处于基本安全状态,2018年和2019年处于安全状态,2017年处于不安全状态。通过深入辨识分析影响人民胜利渠灌区水资源安全的各项指标,发现提升水资源利用效率、推广节水灌溉技术以及实现水资源供需均衡,是确保人民胜利渠灌区水资源安全的关键。

基于序关系分析—独立性权系数法的含水层富水性研究

为评价冯家塔煤矿4煤顶板山西组砂岩含水层富水性,选取了山西组富水砂岩厚度、岩心采取率、砂泥岩互层层数、脆塑性岩厚度比、砂岩岩性系数5个影响因素,利用序关系分析法求出影响山西组砂岩含水层富水性的主观权重,利用独立性权系数法求出客观权重,采用乘法合成法得出综合权重,构建了富水性评价模型。结果表明,冯家塔4煤顶板山西组砂岩含水层富水性较强和强富水区域主要分布在井田南部和西部,弱富水区域主要在井田北部及中部小部分区域。通过对比矿井物探、井下积水区及抽水试验的结果,预测模型准确率较高,与实际情况相符。

基于AHP-熵权法的望虞河西岸圩区活水调度方案多目标优选

以望虞河西岸的甘露圩和荡北圩为研究区,构建水动力-水质模型,选取恰当的水动力、水质和经济成本指标构建活水调度多目标评价指标体系,采用层次分析法和熵权法主客观相结合确定指标权重,决策单圩活水调度最优方案,并与圩区联合调度方案比较活水调度效果。结果表明:利用多目标评价指标体系可有效确定活水调度最优方案;甘露圩最优调度方案为陈家角闸和甘露港闸共同引水,徐家浜闸站以6 m^(3)/s流量抽排;荡北圩最优调度方案为黄塘河闸和五星河北闸引水,珠桥河闸站和五星河闸站共以9 m^(3)/s流量抽排;与单圩活水调度相比,两圩联合调度后畅流活水效果更优。

基于改进TOPSIS模型的山西省水资源承载力与协调发展分析

【目的】为了评估山西省水资源承载力并为未来区域水资源规划与管理提供实际指导,【方法】从水资源、社会、经济、生态四个子系统构建了水资源承载力评价指标体系,利用基于改进组合权重的TOPSIS模型对山西省2011—2020年水资源承载力进行综合评价,并引入改进的耦合协调度模型以准确阐明水资源与经济的耦合协调关系。【结果】结果表明,改进的AHP与反熵权法相结合,可以避免传统AHP中主观因素和熵权法中数据随机性造成的偏差,从而准确估计水资源承载力。评价年份内,山西省水资源承载力逐年提升,总体呈增大趋势。此外,山西省水资源与经济系统间耦合协调程度得到改善,但总体仍处于较低的协调状态,且改进耦合协调度结果能更客观与动态反映水资源与经济子系统之间的耦合协调类型。【结论】2011—2020年山西省水资源承载力呈总体上升趋势但仍有较大提升空间,其中水资源与经济发展之间仍存在局部不协调问题,应进一步优化区域经济产业结构,改善水资源配置,统筹各系统协调发展以综合提升区域未来水资源承载力。

基于水资源配置的空间均衡度评价方法

为量化水资源配置对空间均衡的提升作用,系统评价水资源配置方案空间均衡度,研究基于水资源配置系统“水源-供水设施-受水区-用水户”的整体结构,从水源均衡、设施均衡、单元均衡和用户均衡4个方面分别选择了均衡度评价指标,构建水资源配置空间均衡度综合评价指标体系,并提出基于熵权-TOPSIS法的水资源配置空间均衡度评价方法。以昌邑市水资源配置系统为例,设置12种水资源配置方案来探究不同调控措施对水资源配置空间均衡度的影响。结果表明:该方法不仅可以量化不同调控措施对水源均衡、设施均衡、单元均衡和用户均衡的影响效果,还能够评估配置系统整体的水资源配置空间均衡度,可为水资源配置与空间均衡相关研究提供借鉴。

城市景观水体水质时空分布特征及其评价方法适用性研究

为探究城市景观湖泊水质特征及其水质评价的适用性方法,以兴庆湖为研究对象,选取5个采样点,根据2018年1月至2020年9月水体逐月pH值及TP、NH_(3)-N、DO、COD浓度监测值,采用单因子评价法、综合水质指数评估法、水质健康综合评估法和熵权-TOPSIS法对兴庆湖水质进行评价。结果表明:兴庆湖水质指标存在时空分布差异,水体进入兴庆湖后,除氨氮外,其他水质指标值增大;pH值春夏两季高于秋冬两季,TP质量浓度夏秋两季高于春冬两季,COD、NH_(3)-N质量浓度秋冬季高于春夏季;4种水质评价方法对兴庆湖水质评价结果有差异,经综合比较分析,熵权-TOPSIS法不受指标数量、数据分布等的限制,减少了主观因素的影响,能准确反映水体水质情况。

理论与实践一体化教学复合式成绩评价体系及熵权法应用研究

为实现一流人才培养目标,开展线上线下混合式教学、理论与实践一体化教学改革是行之有效的方法。为了与这种教学模式的转变相适应,学生成绩评价方法也要随之进行改革。依据水利水电工程专业重点课程中理论与实践并重的特点,设计了一套学生成绩评价指标体系。在主观权的基础上,引入了熵权法客观赋权,提出了一种学生成绩评价方法。结合具体课程应用研究表明,与传统方法相比,这种成绩评价方法能客观地反映学生的平时学习情况和最终学习效果,也能促进学生重视理论与实践的有机结合。

秦岭南坡不同林分类型枯落物层和土壤层水文功能综合评价

为探究秦岭地区典型林分下枯落物层和土壤层水文功能差异,采用室内浸水法、环刀法定量研究秦岭火地塘林区油松林、锐齿栎林和华北落叶松林下枯落物层和土壤层持水特征,并借助主成分分析法、熵权法综合评价其水文功能。结果表明:1)3个林分下枯落物层厚度和蓄积量分别为3.11~7.44 cm和5.58~10.02 t·hm^(-2),其中锐齿栎林枯落物厚度最大,而华北落叶松林蓄积量最高;2)枯落物层自然含水率、最大持水率、最大持水量和有效拦蓄量分别为12.54%~102.59%、185.93%~557.7%、14.41~17.8 t·hm^(-2)和7.66~14.34 t·hm^(-2),其中锐齿栎林的最大持水量和有效拦蓄量最大,华北落叶松林则在枯落物自然含水率及最大持水率上表现最佳;3)3个林分下土壤容重均随着土层深度的增加而增加,其值为0.89~1.21 g·cm^(-3),油松林的土壤储水量最低,华北落叶松林下的土壤总孔隙度和毛管孔隙度则最大,0~40 cm土层最大持水量依次为华北落叶松林(257 mm)>锐齿栎林(234 mm)>油松林(231 mm)。通过熵权法综合评价,锐齿栎林在枯落物拦蓄能力方面表现最佳,而华北落叶松林土壤层的持水功能最优,因此建议在今后的森林管理中合理优化树种配置,以更好地发挥其水源涵养功能。

基于AHP-熵权法的鄞西平原河网水环境改善效果综合评价

随着城市化的发展,河流间原有的联系被打断,水动力条件变差,继而引发水质污染、水生态功能衰退等问题。以鄞西平原为例,提出一种基于层次分析-熵权法的水环境改善效果评估方法,在水动力、水质参数的基础上,综合考虑经济效益和感官参数,全面评估水环境改善方案的效果。量化比选研究区提升效果,最终确定方案3为研究区改善效果最优方案。研究表明,基于层次分析法和熵权法的综合评价方法相较于传统仅考虑水动力、水质或其他单一因素的评价方法,能够克服定性数据和主观赋权对评价结果的影响,更加全面地评价不同连通方案的提升效果,实现了方案综合评价与优选。

基于DPSR模型的城市水安全评价与保障能力提升

水安全评价是水资源开发利用与保护的基础,提升城市水安全有利于促进生态环境保护,支撑经济社会高质量发展。基于驱动-压力-状态-响应(DPSR)模型构建以资源安全、社会安全和经济安全为核心的水安全评价指标体系,运用熵权法确定指标权重,以长沙市为实例,对“十三五”期间城市水安全状况进行评估与分析。结果表明:长沙市水安全状况尽管从2018年“不安全”等级提升至2020年“安全”等级,但状态不稳定,进而制定了加强保水工程建设、提升水环境质量、加强水灾害防治能力3个方案,综合考虑方案投入成本并对比水安全提升效果,给出了先后实施方案2—方案1—方案3的长沙市水安全提升优化路径。

基于正交试验泵加压输水管线空气罐参数优化

为探究空气罐在泵加压输水管线发生停泵水锤时,正、负压防护效果影响因子排序,寻求最优参数组合提高空气罐防护效果。基于新疆某输水工程,采用4因素4水平的正交试验方法,使用KYPIPE软件进行水力过渡过程模拟计算,建立正、负压防护效率评价指标对防护效果进行评价;采用熵权法将多目标优化转化为单目标优化,给出正、负压有效防护效率的权重分别为0.27、0.73。结果表明,对水锤防护效果影响最显著的因素为初始气体压力水头。各因素对正压防护效果影响大小排序为初始气体压力水头>入流阻力系数>出流阻力系数>高度直径比;对负压防护效果影响大小排序为初始气体压力水头>出流阻力系数>高度直径比>入流阻力系数;最优方案参数组合为初始气体压力水头为30 m、高度直径比为4、入流阻力系数为10、出流阻力系数为5;对比原方案,优化方案下最大正压降低15.8%,正压有效防护效率提高17.4%;最小负压增加60%,负压有效防护效率提高120%。