Updating of a DRASTIC-based Method for Specific Vulnerability Assessment in Carbonate Aquifers

Abstract

Some methodological modifications are suggested to improve a DRASTIC-based method as a reliable predictor of microbial contamination in extensively fractured and subordinately karstified carbonate aquifers. These modifications will allow a better assessment of vulnerability induced by the concentrated infiltration of surface runoff in two different scenarios: (a) when the karst system is entirely located within an unsaturated aquifer and (b) when the karst system is partially located within a saturated medium. The effectiveness of the updated method has been experimentally verified by comparing the vulnerability values with the results of a hydrogeological and microbiological study at a test site.     

华北山前平原不同含水组垂向水循环规律

地下水是华北山前平原的主要供水水源,其资源属性一直存在争议。以正定试验基地为研究区,通过分析地下水化学、氘氧同位素、14 C测年等在垂向上的变化特点,对比不同含水组地下水与大气降水的氘氧同位素含量关系,研究华北山前平原典型研究区504m深度内不同含水组地下水在垂向上的循环规律,确定360m为该区地下水含水系统的内部界限,其上构成浅层含水系统,其下构成深层含水系统。     

岩溶含水层脆弱性评价方法探讨

阐述岩溶地下水脆弱性的概念和岩溶含水层的特殊性,介绍几种有代表性的岩溶含水层脆弱性评价方法,认为DRASTIC模型是目前应用最广泛的,但该模型没有单独考虑岩溶含水层的特殊性;EPIK法是第1个专门针对岩溶含水层的方法,用于水资源保护区划分,但评价体系和权重系统不太完善;越南模式是一种极端简化的方法,在数据较少的地区有一定的借鉴意义;Slovenia模式为最新方法,是迄今为止对岩溶含水层脆弱性指标诠释最为详细的方法,但需要更多的实践检验。目前岩溶含水层脆弱性评价在机理研究、权重分配、数据获取、结果验证、定量研究和方法选取等方面仍面临着挑战,也是今后的发展趋势和研究方向。     

Rain and groundwater as phosphorus sources of a small reservoir

At Broa hydroelectric reservoir 82% of phosphorus (P) input is from rivers, 12% from groundwater seepage input and 6% from direct rainfall. The reservoir retains 15% of incoming P, corresponding to 73 mg/m²/year sedimentation. Proportions of water input are 36% from groundwater seepage in the dry season and 68% from seepage and 3% from direct rainfall in the rainy season; the remainder comes from rivers. Average P concentration during the 1996 rainy season was 27 μg/L in rain, 6.1 in groundwater, 68.54 in rivers and 33.56 in outflow.     

模糊综合评价在区域水资源承载力研究中的应用

区域水资源承载力是进行生态环境建设和确定社会经济发展方向的资源基础。阐述了水资源承载力的内涵,选取了区域水资源承载力的指标体系:人均供水量、水资源利用率、耕地灌溉率、供水模数、需水模数、生态用水率,对平坝区进行了水资源承载力模糊综合评价计算,对今后的水资源开发提供决策依据。     

流域地下水可持续开采量的定义及评价体系

阐明流域地下水可持续开采量概念提出的必要性,并分析传统可开采量概念在解决现有问题时的局限性。从提高流域内整体水资源的利用率出发,以实现综合效益最佳,环境负效应最小为原则,以流域内整体水资源的人工调控技术为手段,提出了流域地下水可持续开采量的概念并论述其概念的内涵与组成。通过与传统可开采量概念的比较和分析进一步阐述新概念所具有的进步性,最后建立了流域地下水可持续开采量的评价体系。     

Development of a Protection Strategy of Karst Limestone Aquifers: The Merida Yucatan,Mexico Case Study

In many regions karstic aquifers constitute the only available source of drinking water. Due to the high risk of contamination in these aquifers, a comprehensive groundwater protection and control system must be designed and established. It has recentlybeen proposed that Hydrogeologic Reserve Zones (HRZ) can be established as a tool for the groundwater management in these aquifers. The following approach is proposed in order to establish the HRZ in karstic aquifers: including several generalstrategies for the protection of the ground waters within them, as well as the zoning of the land use and the development of acode of practice. A general procedure is proposed for the development of code of practice for ground water protection inkarst aquifers, which is applied as a case study in Merida, Yucatan, Mexico.     

Evaluation of Groundwater Resources in Lower Cretaceous Aquifer System in Sinai

The Sinai Peninsula has an area of 61000 km² and its populationis about 325000. It is located in an arid area. Extensivedevelopment in the socio-economic, industrial and agriculturalis in process. Although Lower Cretaceous aquifer is the mostprospective aquifer in Sinai, it is not yet precisely evaluated.Spatially distributed areas of good groundwater quality suitablefor various types of development are not identified.The current article presents a comprehensive assessment of thehydrogeological information and hydrological data. Accordingly,three aquifer zones have been identified. Groundwater reserve wasestimated and groundwater balance has been developed. Developmentpotential was evaluated. Development criteria were proposed and applied.Suitable areas for domestic and irrigation purposes weredelineated. Results indicated that the aquifer contains 308 billion m³ ofgroundwater of which a considerable volume is of good quality. Bylowering the present water level some 200 meters, the aquiferyielded 3643 million m³, which is sufficient to supply thepresent rate of withdrawal for 445 years. The results are considered to be usefulfor preparing groundwater master plans in Sinai. Under the properwater management, Sinai could be self sufficient in satisfying itsdomestic water demand.     

油气田区承压含水层地下水污染机理及其脆弱性评价

根据研究区地质构造及水文地质概况,分析了研究区承压含水层地下水有机污染的机理,建立了针对该地区承压含水层地下水污染脆弱性评价指标体系,并应用神经网络技术作为评价体系中参数的赋权方法;由ANN与GIS耦合技术得到的研究区承压含水层地下水污染脆弱性区划图比较好地符合研究区的实际情况。     

Chloride and total phosphorus budgets for Lake Nipissing,headwater of Lake Huron,Ontario, Canada

Anthropogenic sources of total phosphorus (TP) and chloride (Cl^?) to lakes and rivers have been issues of concern for many decades in the Great Lakes Basin with northern Boreal Shield headwater tributaries less well studied. In the Sturgeon River – Lake Nipissing – French River basin, a headwater basin of Georgian Bay, Lake Huron, water quality monitoring of major inflows to Lake Nipissing, the third largest inland lake located entirely within Ontario, is only available from the mid-1960s to the 1990s. During the period of 2015–2018, we conducted monthly water quality surveys of major and minor inflows for two water years and have generated the first chloride (Cl^?) and total phosphorus (TP) elemental budgets for the lake. Review of available long-term concentration data indicate decreasing TP concentrations by decade in major inflows, but select inflows continue to exhibit concentrations above provincial objectives, including inflows from agricultural areas that are no longer part of provincial monitoring programs. Some inflows also show high average Cl^? concentrations with potential influences (e.g., road salt, agricultural activities) to stream water quality throughout the year. Water and elemental budgets indicate that while specific runoff (l/s/km²) is quite similar across contributing catchments, yields of Cl^? and TP (kg/ha/yr) are disproportionately higher in catchments with urban and agricultural activities. While uncertainties in the water balance and elemental yields remain, this first effort to quantify annual elemental budgets of Lake Nipissing highlights the need to develop community-based, spatially distributed water quality surveying for long-term ecosystem monitoring and future planning.     

From an open-access to a state-controlled resource: the case of groundwater in the Kathmandu Valley,Nepal

Groundwater is no longer an open-access resource in Kathmandu. Perceptions of groundwater are changing from an “infinite” to a “finite” resource and the role of the government from supply developer to caretaker of the resource. In this context, this paper aims to unfold how perceptions of groundwater in Kathmandu Valley, Nepal, are changing from an open-access resource to an overexploited, depleted, degraded, vulnerable and state-controlled resource. In the process, it produces an aggregated picture of resource availability, development dynamics, impacts and responses in the area; suggests some “soft-path” approaches for groundwater management; and discusses implications of the experience for other areas.     

邢台山前倾斜平原区孔隙水脆弱性评价

利用DRASTIC模型和MAPGIS叠加技术,并采用层次分析法,构建地下水脆弱性评价系统,将该评价系统应用于邢台市山前倾斜平原区孔隙水脆弱性评价。结果表明,评价结果与实际情况比较吻合。     

江汉-洞庭平原地下水功能评价与区划

为了合理开发利用江汉-洞庭平原的地下水资源,通过资料收集、野外调研,构建了包括资源功能、生态功能与地质环境功能属性指标数据层的评价体系。将江汉-洞庭平原划分为4个地下水功能评价区与17个评价亚区,运用层次分析法与Map GIS软件空间分析功能,对江汉-洞庭平原地下水资源功能区、生态功能区与地质环境功能区进行了划分。最后,综合分区与主导功能性分析结果,将江汉-洞庭平原地下水功能划分为可持续性强、较强、一般、较弱与弱5个等级并确定了分布范围。研究成果可为江汉-洞庭平原地下水资源可持续利用、地质环境及生态环境保护规划提供科学依据。     

水均衡法在区域地下水资源量评价中的应用研究

地下水资源是我国西北地区水资源的主要组成部分,对地下水资源全面科学的综合评价是解决水资源缺乏问题的基础性工作。详细阐述了区域地下水资源评价方法,水均衡法特点、基本原理及计算内容。通过收集资料,对西北某地区地下水资源进行了定量计算,为科学合理地利用地下水,保持水土平衡,促进该地区经济可持续发展提供了依据。     

页岩气开采区地下水脆弱性评价模型

为了更准确评价页岩气开采过程中水力压裂和废水回注对地下水的影响,需要采用不同指标体系的模型对地下水脆弱性进行评价。通过分析页岩气开采过程中污染物的潜在运移途径,在DRASTIC模型的基础上分别建立了开采井区地下水脆弱性评价模型DIRTEV和回注井区地下水脆弱性评价模型DIRWOCT。根据相关资料对模型中各评价因子进行了分级及评分,运用模糊综合矩阵法确定了各因子权重,并利用单参数法对评价结果进行了敏感性分析。对四川某页岩气采区的评价结果表明,所建模型能较好地应用于页岩气开采区地下水脆弱性评价。     

地下水可持续开采量评价方法综述

本文评述了地下水开采量概念的发展过程,指出为实现可持续开采量的评价,国内外目前研究的焦点主要集中在可持续开采量的可更新能力、生态和环境用水约束与社会经济发展及环境保护的协调优化等方面。同位素和地球化学示踪、GIS等新技术的发展及新技术与传统评价方法的有机结合大大促进了可持续开采量评价的发展。本文着重讨论了当前水均衡法、数值模拟、同位素技术和基流分割等评价方法的优缺点,以及在实现地下水可持续开采量评价方面的进展和面临的问题,认为多种方法有机结合是未来的发展方向。     

多元因子分析模型在河流健康评价中的应用——以苏子河水质特性研究为例

为顺应河流生态可持续发展,提出健康河流、生命河流等概念,维持河流生态系统健康已经成为流域综合管理的必然趋势。综合运用水文学、水力学、泥沙地貌学和水生生态学的基本理论和方法研究河流生态健康的表征因子,确定各因子的阈值,建立流域性水体水质可续发展评价体系。以河流可持续发展为基础,引用代表性的相关指标进行筛选,对流域水质指标进行数值化分析,以苏子河流域水质特性为研究对象,选取出评估河流健康状况的环境因子,客观反映出中小河流域健康状况,为河流的可持续管理和生态环境建设提供参考。     

太行山前丘陵区基岩裂隙水赋存的非均一性和易疏干性特性

根据碧流河流域生态特征,分析了适合该流域的河道生态需水计算方法,应用于碧流河水库兴利调度,并以生态目标为基础,确定下游河道的生态需水量。结果表明:碧流河水库下游河道生态环境基本供水量及改善供水量分别需要2 765万m3和4 250万m3。为了保护和改善河流生态环境,促进流域水资源可持续利用,需要采取最严格的用水管理制度,加大非常规水源的开发利用力度,并结合调水工程以及河库连通工程等相关措施。     

呼伦贝尔高平原地区浅层地下水脆弱性评价

在充分考虑呼伦贝尔高平原地区水文地质条件的情况下,提出了基于DRASTIC模型的DRASL评价方法,利用层次分析法确定各指标权重,结合Arc GIS平台对呼伦贝尔高平原地区浅层地下水进行脆弱性分区,并对评价指标的合理性做了相关的敏感性分析。结果表明,高脆弱性地区主要分布在海拉尔区周边和满洲里市东郊,土地利用和地下水位埋深是影响呼伦贝尔高平原地区地下水脆弱性的关键因素。     

上海市地下水开发利用和保护对策

对上海市地下水的开发利用现状进行分析,指出存在的问题,提出要从健全法律法规、加强管理、提高科技手段等方面入手,进一步合理开发利用和保护上海市地下水资源,实现可持续利用。