Parametric uncertainty analysis on hydrodynamic coefficients in groundwater numerical models using Monte Carlo method and RPEM

Groundwater resources are the only source of water in many arid and semi-arid regions. It is important to manage these resources to have a sustainable development. However, there are many factors influencing the accuracy of the results in groundwater modeling. In this research, the uncertainty of two important groundwater model parameters (hydraulic conductivity and specific yield) were considered as the main sources of uncertainty in estimating water level in an unconfined aquifer, in Iran. For this purpose, a simple method called Rosenblueth Point Estimate Method (RPEM) was used to assess groundwater modeling parametric uncertainty, and its performance was compared with Monte Carlo method as a very complicated and time-consuming method. According to calibrated values of hydraulic conductivity and specific yield, several uncertainty intervals were considered to analyze uncertainty. The results showed that the optimum interval for hydraulic conductivity was 40% increase–30% decrease of the calibrated values in both Monte Carlo and RPEM methods. This interval for specific yield was 200% increase–90% decrease of the calibrated values. RPEM showed better performance using the evaluating indices in comparison with Monte Carlo method for both hydraulic conductivity and specific yield with 43% and 17% higher index values, respectively. These results can be used in groundwater management and future prediction of groundwater level.

     

荆州市地下水动态特征及影响因素分析

利用2008~2011年4年荆州地区36个水位观测孔、30个水质监测孔的连续监测资料,结合地下水补径排条件,分析了该区上部孔隙承压水水位和水质的时空变化特征及其影响驱动因子。结果显示:(1)荆州地下水位动态类型分为自然动态型和人为动态型两种,不同类型地下水水位动态规律在时空分布上有明显差异,呈现出周期性、同步性、特殊性等特点。4167%~50%的监测孔地下水位处于稳定状态,2222%~3611%的监测孔地下水位下降幅度大于02 m,1944%~3611%的监测孔地下水位上升幅度大于02 m,地下水位动态主要受气候条件与人工开采条件影响。(2)荆州地区地下水质不容乐观,整体较差。连续四年均超标的指标有总硬度、亚硝酸盐、氨氮、砷、铁、锰、溶解性固体含量,同时在部分监测点存在超标异常情况,铁、锰、砷的超标与江汉平原区域特有的原生地质环境条件密切相关,而其它组分的超标在很大程度上受到人类活动的影响     

Groundwater: a regional resource and a regional governance

Groundwater is a valuable renewable resource for human life. The two major threatening issues being faced by groundwater are its depletion and degradation which affect both the quantity and the quality of groundwater. Though scientific output has progressed well ahead in the domain of groundwater, very little has been done with respect to the establishment of the groundwater governance framework. Groundwater is perceived as a widely distributed resource, but it is fundamentally a local entity. The paper presents the groundwater governance framework from the regional perspective of Fatehgarh Sahib district of Punjab, India—an over-exploited groundwater region.     

Spatial variability of shallow groundwater level, electrical conductivity and nitrate concentration, and risk assessment of nitrate contamination in North China Plain

In recent years, nitrate (NO3) contamination of groundwater has become a growing concern for people in rural areas in North China Plain (NCP) where groundwater is used as drinking water. The objective of this study was to evaluate groundwater resource level, to determine groundwater quality and to assess the risk of NO3 pollution in groundwater in Quzhou County in the NCP. Ordinary Kriging (OK) method was used to analyze the spatial variability of shallow groundwater level, groundwater electrical conductivity (EC) and NO3-N concentrations, and Indictor Kriging (IK) method was used to analyze the data with NO3-N concentrations equal or greater than the groundwater NO3 pollution threshold (20 mg L(-1)). The results indicated that groundwater level averaged 9.81 m, a level 6 m lower than in 1990. The spatial correlation distances for groundwater level, EC and NO3-N concentration were 21.93, 2.19 and 3.55 km, respectively. The contour map showed that shallow groundwater level areas extended from north to south across the County. Groundwater EC was above 3 dS m(-1) in the most part of the northern county. Groundwater NO3 pollution (NO3-N> or =20 mg L(-1)) mainly occurred in the County Seat areas due to wastewater irrigation and excessive fertilizer leaching from agricultural fields. At Henantuang town, besides suburban of the County Seat, groundwater was also contaminated by NO3 shown by the map generated using the IK method, which was not reflected in the map generated using the OK method. The map generated using the OK method could not reflect correctly the groundwater NO3 pollution status. The IK method is useful to assess the risk of NO3 pollution by giving the conditional probability of NO3 concentration exceeding the threshold value. It is suggested that risk assessment of NO3 pollution is useful for better managing groundwater resource, preventing soil salinization and minimizing NO3 pollution in groundwater.     

Assessment of groundwater contamination in a suburban area of Chennai,Tamil Nadu,India

Groundwater source is the major source of drinking water in most of the suburban areas of India. Groundwater quality was analyzed for pH, TDS, hardness, chloride, fluoride, nitrate, ammonia, phosphate, total coliform and E. coli for the period of January–December 2013. Samples were collected from 10 locations that include 10 shallow wells and 10 deep wells in each location. The quality variation between both shallow and deep wells during pre- and post-monsoon was analyzed. The improper disposal of solid waste and the distance of septic tank were pronounced on E. coli count. The analysis reveals that groundwater contamination is influenced by seasonal changes, environmental condition of the well and maintenance of the well. The high contamination was observed in the wells which are near to the Pallikaranai marsh, and during post-monsoon season, the total dissolved solids and nitrite parameters are slightly increased, whereas chloride increases during pre-monsoon season. Correlation analysis reveals that the chloride and nitrite have a significant relation. The results suggested that the groundwater immediately needs broader protection.     

Modeling groundwater flow and its associated environmental problem in a lowland coastal plain: a first step towards a sustainable development plan

Groundwater is an important resource in the alluvial coastal lowland plains. In the Shiroishi lowland plain, southwestern Kyushu Island of Japan, land subsidence due to groundwater development has long been recognized as an environmental issue. Land subsidence can have several negative economic and social implications. In this study, an integrated numerical groundwater and land subsidence model, which combines a three-dimensional numerical groundwater flow model and a one-dimensional soil consolidation model, was used to simulate the dynamic groundwater flow and ground subsidence due to pumping. On the other hand, a groundwater optimization model was also formulated to search for an optimal safe yield of groundwater pumping without violating physical, environmental, social-economic constraints. The model results reveal that groundwater levels in the aquifers greatly vary from season to season in response to varying climatic and pumping conditions. Consequently, land subsidence has rapidly occurred throughout the area with the central prone in Shiroishi plain. The study also proposes a countermeasure against subsiding process in the area by means of numerical models. The optimization model result suggests that pumping can be increased in the northern part of the study area without leading to significant land subsidence.     

Awareness on usage of contaminated groundwater around Perungudi dumpsite,Tamil Nadu,India

Groundwater is the major drinking water source both in urban and rural area. Mostly in urban and peri-urban areas of developing countries, groundwater is more susceptible to contamination due to urbanization. Therefore, the awareness of usage of groundwater has to be analysed to frame the policy measures and to suggest proper intervention programs. The community residing around Perungudi dumpsite, Tamil Nadu, India, has been chosen to assess the awareness on usage of groundwater using regression model. The groundwater flow and quality analysis assessed technically is in line with people’s perception on groundwater quality. The model results clearly indicate that the socio-economic status (β = 0.167) and distance (β = 0.305) play a major role in groundwater usage. Though 31.2 % of respondents reported that the water quality is bad within 1 km in the contaminated area, 45 % of low socio-economic categories depend on well water. This shows the unawareness of health issues due to the usage of contaminated water. Proper policies have to be framed, especially for the contaminated site to get rid of adverse health impacts due to long-term exposure of contaminated water.     

Spatial assessment for groundwater quality based on GIS and improved fuzzy comprehensive assessment with entropy weights

The objective of the research is to evaluate spatial groundwater quality based on improved fuzzy comprehensive assessment model with entropy weights(FCAEW)in geographical information system(GIS)environment.This paper explores the method of comprehensive evaluation of groundwater and sets up an evaluation model applying GIS and FCAEW.Groundwater samples were collected and analyzed from 29 wells in Zhenping County,China.Six parameters were chosen including chloride,sulfate,total hardness,nitrate,fluoride and color.Better spatial interpolation methods for evaluated parameters are found out and selected according to the minimum cross-validation errors from the interpolation methods.FCAEW model was carried out with the help of GIS which makes the evaluating process simpler and easier and more automatically,effectively,efficiently and intelligently.The result embodies the feasibility and effectiveness of FCAEW in GIS when compared with other comprehensive evaluation methods.     

Influence of global warming on coastal infrastructural instability

The increasing infrastructure instability is an important issue in relation to the influences of global climate change in urban areas. A serious issue pertaining to this is the dual nature of damage triggered by events combined with climate change and natural hazards. For example, catastrophic damage could result from the combination of global warming with a great earthquake, which is a worst-case scenario. Although this worst-case scenario has rarely occurred and presents a low probability of occurrence, countermeasures must be prepared in advance based on an appropriate response and adaptation strategies. After an overview of possible infrastructural instabilities caused by global warming, methodologies are proposed placing emphasis on the increasing probability of infrastructural instability triggered by natural hazards resulting from groundwater-level (GWL) variations. These effects are expected to be particularly serious in coastal regions because of the influence of the rising sea level resulting from global warming. The influence of sea-level rises (SLR) will become apparent along with land subsidence because groundwater abstraction will become severe in coastal regions. Additionally, the probability of earthquake liquefaction increases if GWL rises in accompaniment with SLR. Using case histories, we examined the possible occurrence of these natural hazards as a result of global warming. Finally, possible countermeasures and adaptation strategies for reducing and mitigating infrastructure damage accelerated by global warming are described for each case in specific regions. In particular, special attention should be paid to adaptation strategies in coastal lowlands, which particularly suffer from the effects of land subsidence.     

基于GMS的山区三维地质模型及应用研究

本文基于GMS平台,在综合分析重庆某山区地质平面图、地质剖面图、钻孔资料等数据基础上构建了三维可视化地质模型。模拟结果表明:研究区砂泥岩倾斜互层的沉积顺序和不同岩性的空间分布情况与该区已有资料相一致;模型剖面与实际地质剖面面积之比约为1.15,主要岩性面积百分比相对误差绝对值均在15%以内。运用该模型概化为三维水文地质模型,模拟得出研究区地下水流场空间分布,体现了三维地质模型在地下水数值模拟方面的运用价值。该模型的构建为山区区域地质结构研究提供了参考,也为今后该地区开展地下水相关工作打下了基础。     

Modelling the resilience of Australian savanna systems to grazing impacts.

Savannas occur across all of northern Australia and are extensively used as rangelands. A recent surge in live cattle exports to Southeast Asia has caused excessive grazing impacts in some areas, especially near watering points. An important ecological and management question is "how resilient are savanna ecosystems to grazing disturbances?" Resilience refers to the ability of an ecosystem to remain in its current state (resist change) and return to this state (recover) if disturbed. Resilience responses can be measured using field data. These responses can then be modelled to predict the likely resistance and recovery of savannas to grazing impacts occurring under different climatic conditions. Two approaches were used to model resilience responses. First, a relatively simple mathematical model based on a sigmoid response function was used. This model proved useful for comparing the relative resilience of different savanna ecosystems, but was limited to ecosystems and conditions for which data were available. Second, a complex process model, SAVANNA, was parameterised to simulate the structure and function of Australian savannas. Simulations were run for 50 years at two levels of grazing to evaluate resistance and then for another 50 years with no grazing to evaluate recovery. These runs predicted that savanna grasslands were more resistant to grazing (changed less) than red-loam woodlands, which recovered relatively slowly from grazing impacts. The SAVANNA model also predicted that these woodlands would recover slightly slower under the climate change scenario projected for northern Australia.     

A social and ecological imperative for ecosystem-based adaptation to climate change in the Pacific Islands

Climate change is predicted to have a range of impacts on Pacific Island ecosystems and the services they provide for current and future development. There are a number of characteristics that can make adaptation approaches that utilise the benefits of ecosystems a compelling and viable alternative to other adaptation approaches. The objective of this paper is to determine what level of relative influence technical and planning considerations currently have in guiding the recognition and application of ecosystem-based adaptation (EbA) approaches in the Pacific Islands context. The technical feasibility of EbA in relation to the expected impacts of climate change and the compatibility of adaptation planning processes of the Pacific Islands with EbA requirements was considered. The main barrier to fully implementing EbA in the Pacific Islands is not likely to be financial capital, but a combination of stable technical capacity within government departments to advise communities on EbA opportunities and the compatibility of planning frameworks.     

Use of geographic information systems for assessing groundwater pollution potential by pesticides in Central Thailand

This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution in Thailand. The study area included three provinces, Kanchana Buri, Ratcha Buri, and Suphan Buri, located in west-central Thailand. Factors used for the vulnerability assessment included soil texture, slope, land use, well depth, and rainfall. These vulnerability factors were reclassified to a common scale, and a weighted average was computed to yield a vulnerability score. Vulnerability factors and weights were assigned considering pesticide concentrations in 90 wells throughout the study area. Well depth was the most significant vulnerability factor. Groundwater vulnerability maps were generated for several pesticides. The eastern, agricultural part of the study area has relatively deep wells and fine soils. Shallow wells are present in the mountainous west; however, fewer pesticides are applied in that region. Consequently, much of the study area had a medium groundwater vulnerability rating, although there were pockets of high vulnerability, for example, in agricultural areas with shallow wells. The groundwater vulnerability maps are effective for identifying locations warranting more detailed groundwater pollution and vulnerability investigations.     

Concentrations and activity ratios of uranium isotopes in the groundwater of the Okchun Belt in Korea.

Groundwater samples obtained from the Okchun Belt in Korea were separated into particulate and filtered fraction using a 0.45 microm membrane filter and concentrations and activity ratios of uranium isotopes in the fractions were determined by chemical separation and alpha-spectrometric measurements. Most of the uranium isotopes in the groundwater were found in the filtered water. Only less than 1% of the total uranium was detected in the particulate fraction. The concentrations and activity ratios of uranium isotopes in the groundwater measured in this study were variable, depending upon sampling site. Owing to a rapid material exchange between the subterranean hot waters and the rock strata, the concentrations of 238U in the groundwater in the hot spring area were found to be about four times higher than those elsewhere. Because of the alpha-particle recoil effect, the activity ratios of 234U/238U in the groundwater taken at "cold" spring sites were variable within the range 1.20 to 3.58, depending on the residence time of the groundwater. In the hot spring area, the activity ratios of 234U/238U were close to the equilibrium value (1.10 +/- 0.07) due to rapid erosion of the rock strata by the hot spring water.     

Assessment of groundwater potential in Tirukalukundram block of southern Chennai Metropolitan Area

Groundwater is an important resource in all major urban centres. Continuous extraction leads to degradation and depletion in the water quality which can be protected by selecting proper groundwater recharging techniques. The present study aims to determine the groundwater potential by integrating the remote sensing and geographic information system which helps to identify the locations which are in critical stage and immediate steps can be taken to recharge the groundwater. Thirukalukundram block of Kanchipuram district in Tami Nadu, India, has been chosen as study area. To demarcate the groundwater potential zone, surface attributes such as geomorphology, land use/land cover, contour map, drainage density and sub-surface attributes such as lineaments and soil maps are created using satellite imageries, toposheet, soil and geomorphology data of the study area. The thematic maps prepared using geographic information system and weights have been assigned to the attributes by considering the influence on the storage capacity of groundwater. Four categories of groundwater potential zones such as below low, low, moderate and high have been classified. From the analysis, 5% along the coastal plain area covers high groundwater potential zone, 20% of the area towards north-west and south-west hold moderate groundwater potential. 60% of the total area hold low groundwater potential zone which are located towards south-west direction. 15% of the study area contains below low groundwater potential zone in parts of south-west direction. This study helps to identify the suitable locations for extraction and recharge of groundwater.     

人类活动对川东平行岭谷区岩溶地下水化学性质季节变化的影响

以川东平行岭谷区典型岩溶槽谷--北碚槽上为研究区域,通过对8月和11月的岩溶地下水水化学性质研究,发现槽上岩溶地下水的化学性质呈现明显的季节性：电导率、矿化度、SO42-浓度及HCO3-浓度都是8月大于11月,与气温和降水量的变化相对应,也与人类在8月份对土地利用的强度大于在11月份对土地利用的强度相对应。研究区地下水的化学性质与人类活动对土地利用的季节差异具有比较明显的对应关系,为进一步认识岩溶地下水的时间变化规律提供科学数据,也有利于认识人类活动对生态环境产生的影响,从而采取更加合理的措施来治理和保护岩溶地区有限的地下水资源,满足人们的生活和生产需要。     

Efficient energy management strategies for hybrid electric vehicles using shuffled frog-leaping algorithm

This paper proposes two novel approaches for the problem of energy management in hybrid electric vehicles. Shuffled frog-leaping algorithm (SFLA) is a recently proposed population-based optimization algorithm. This paper first formulates energy management as an optimization problem and optimizes the problem using SFLA. Then the paper makes use of SFLA as a training algorithm to train artificial neural network (ANN) and this SFLA-trained ANN is used for energy management. Interestingly, the proposed approaches of this paper are found to be robust and more efficient than contemporary approaches.     

三峡库区消落带农用坡地氮素流失特征及其环境效应

三峡库区消落带坡地的自发农用较为常见,消落带的这种利用方式可能加剧养分流失并对库区水环境造成影响。通过对库区2011~2013年3个落干期消落带农用坡地的地表径流、壤中流中氮素形态与浓度进行定位监测,研究消落带农用坡地氮素流失特征及其环境效应。结果表明：常规施肥下,消落带农用坡地侵蚀模数为1 443 kg/（hm2·a）,落干期内坡地平均径流量为230 mm,径流系数为0.58,其中壤中流流量占总径流量的77%。历次降雨产流事件中常规施肥处理时,地表径流、壤中流中TN平均浓度分别是4.85±0.85、20.73±2.05 mg/L,落干期地表径流（泥沙）和壤中流的TN流失量分别为6.63±1.19、35.22±3.38 kg/hm2,分别占当季施肥量的2.2%、11.7%。可见,随壤中流流失是三峡库区消落带农用坡地氮素流失的主要途径。与常规施肥处理相比,减量施肥处理使地表径流（泥沙）、壤中流TN流失通量分别显著降低了25%、48%,表明减少氮肥用量可以显著降低消落带农用带来的环境风险,建议消落带农用地氮肥进行减量施肥,使其既不影响作物产量,也显著降低氮流失。 关键词： 三峡水库;消落带;地表径流;壤中流;氮负荷;减量施肥     

Integrating ecosystem services evaluation and landscape pattern analysis into urban planning based on scenario prediction and regression model

ABSTRACT

Urban planning has become a widely concern for minimizing the negative effects of urban expansion on terrestrial ecosystems. We developed an interdisciplinary modeling framework to evaluate the effectiveness and shortcomings of urban expansion management strategies. A three-step method was applied to Yinchuan Plain in the northwestern of China, including (1) analyzing the relationship between landscape pattern and ecosystem service values through mathematical statistics; (2) predicting landscape pattern and ecosystem services change under different scenarios based on cellular automaton model (SLEUTH-3r model); and (3) designing and validating optimized scenario through integrating historical analysis experiments and future multi-comparison suggestions. Results have suggested that landscape composition and configuration can significantly affect regional ecosystem service values, especially the connectivity and shape of landscape. Compact urban growth policy and medium environment protection policy are the appropriate setting for urban expansion plan. Optimization validation of the combined designed scenario implied the reliability of this method. Our results highlighted the significance of integrating application of landscape pattern analysis, ecosystem service value evaluation, model simulation and multi-scenario prediction in urban planning.     

A quantitative water resource planning and management model for an industrial park level

This paper introduces an integrated water management model at the industrial park level. It suggests four approaches to water management: first, direct water reuse among users; second, water reuse among users by blending with freshwater; third, water reuse between users and a wastewater treatment plant; and fourth, groundwater recharge by reclaimed wastewater or other feasible applications in order to optimize the overall water efficiency. The model results in a comprehensive management methodology for optimizing water resources within an industrial park, seeking potential water reuse among industries, and incorporating the size and cost of reclaimed wastewater delivery systems. A case study is employed to test the model’s feasibility. An economic analysis of the optimized water use network is also carried out, showing the potential water and cost savings.