Effect of Land-Use Change and Artificial Recharge on the Groundwater in an Arid Inland River Basin

The spatial-temporal variability of groundwater in an inland basin is very sensitive to human activity. This study focused on groundwater changes in the Alagan area within the Tarim Basin, China, with the aim of analyzing the effects of land-use change and artificial recharge on the response characteristics of groundwater. The distributed hydrological model MIKE SHE was introduced for modeling the influence of land use and artificial recharge on groundwater. Based on the runoff variation of this area, we selected three periods to simulate and analyze the response of groundwater. The results of land-use change indicated that there were significant changes from 1980 to 2000. The changed region accounted for 11.93 % of the total area, and the low coverage grasslands showed the greatest reduction. The simulation of hydrological processes before artificial recharge showed that the groundwater depths differed greatly with land-use types. Response analysis of groundwater to artificial recharge showed that the regions in which groundwater decreased were mainly distributed in grassland and bare land. Moreover, spatial autocorrelation coefficients indicated positive spatial autocorrelation of groundwater depths, but these began to reverse in 2010. Overall, land use and artificial recharge have a great influence on the time and spatial distribution of groundwater. Artificial recharge has played a positive role in improving groundwater conditions, but did not change the decreasing trend in time and space. The adaptation of environment to the decrease of groundwater presents as degradation. Groundwater conditions could be improved to some extent by the artificial recharge, but its change seems to be an irreversible process. Overall, this response study provides insight into estimations for exploration of water resources in arid areas.     

Modeling of Groundwater Artificial Recharge by Reactivating an Old Stream Bed

This paper refers to the development and verification of a groundwater artificial recharge model in Xanthi plain, Thrace, Greece. The relative geological and hydrogeological research of the study area is described, as well as the artificial recharge application by reactivating an old stream bed of Kosynthos River, since 1994. The simulation of the aquifer system of the study area was achieved by the use of MODFLOW and involves both the model calibration and prediction of the aquifer system response. The verification of the 9-year-period model prediction for the first 7 years (1995–2001) proved successful, while the respective procedure for the last 2 years, 2002 and 2003, could not result in acceptable estimations.     

Impact of Flood Spreading on Groundwater Level Variation and Groundwater Quality in an Arid Environment

In arid and semiarid areas, bimodal and high rainfall leads to infrequent flood that can be extremely damaging. To reduce the impacts of persistent intra-seasonal drought and also to reduce flood damaging in arid and semiarid areas, rainwater storage is a prerequisite that keeps water far from evapotranspiration, increases groundwater level and decreases flood hazards modification to exchange between surface water and groundwater through flood spreading, dams, etc. The purpose of this paper is to delineate and explain variations in groundwater recharge and groundwater quality along an ephemeral stream that has been modified by flood spreading. Groundwater samples were collected from 14 deep wells located at different distances from flood spreading projection area (FSPA) in 1 month interval during September 2005 to September 2008. Groundwater quality was followed via Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, Hco₃^- SO₄^2-, Electrical Conductivity (EC) and pH measurements for two time periods between 2005 and 2008. The results show significant impact of flood spreading in groundwater table and groundwater salinity variation. Groundwater table decreased in all study wells, but groundwater drawdown increased by increasing the distance to FSPA (during 4 years study, 11.02 m in the well located at 20 m of FSPA versus 38.88 in the well located at 1,825 m). Also ion concentration increased in all of the wells during the study period, but the increasing ion concentration was significantly less important in FSPA closeness.     

Recharge Wells Site Selection for Artificial Groundwater Recharge in an Urban Area Using Fuzzy Logic Technique

In arid and semi-arid area, groundwater is the most important water resources. Surface runoff harvesting is the most important process in the artificial recharge of groundwater that should increase groundwater quality and quantity. Urban impervious area provides an appropriate surface to produce adequate amounts of runoff. Groundwater recharge via recharge wells is one of the successful direct sub-surface methods. As many cities around the world face issues of water scarcity due to a fast and unsustainable urbanization, identify the best locations of groundwater recharge wells is an interesting relevant topic, especially in the arid and semi-arid area. Selection of a suitable area for groundwater recharge could increase efficiency of the recharge wells. In this study, the best location of recharge wells was investigated in Urmia city located in the North-west of Iran using fuzzy logic technique. In this study, locations of the drainage channel junctions with adequate potential of surface runoff were determined using SWMM. Appropriate locations for recharge wells were determined based on different layers including distance to runoff harvesting points, distance to the production water wells and depth of groundwater table. Hydraulic condition (hydraulic conductivity and specific recharge) was also used separately. The input layers were prepared using geostatistical interpolation techniques in ArcGIS 9.3 software. Mamdani fuzzy inference system was applied to incorporate the fuzzified input layers. Finally, in each area, pixels with the highest value were proposed as suitable locations for recharge wells. Based on the results, the number of pixels with “High” priorities increased when the hydraulic conductivity was used to site selection. Comparing hydraulic conductivity layer and selected location of the recharge wells shows that the area with low hydraulic conductivity and the area closed to the production water wells has not suitable priority for recharge wells.     

泾惠渠灌区干旱时段内的地下水动态

泾惠渠灌区是陕西重要的农业生产基地,研究灌区干旱时段的地下水动态对灌区农业生产具有重要意义。通过灌区多年的降水量资料,采用Z指数法选取了灌区的典型干旱时段,然后选取灌区内的典型观测井位分析了其干旱时段内地下水动态特征。     

利用黄河水回灌某漏斗区浅层地下水条件分析

在研究滑县—内黄—清丰—濮阳—南乐地下水降落漏斗分布范围内水文地质特征和调蓄空间的基础上,探讨利用黄河及其支流等地表水源,通过天然河道、人工渠道、回灌渗井等回灌调蓄补给当地地下水的可行性。通过分析认为,漏斗区地表岩性渗透性强,垂直变水平管井施工技术成熟,因此,利用黄河水回灌调蓄漏斗区地下水经济合理、技术可行。通过调蓄可以缓解区内水资源紧缺的形势,控制地下水降落漏斗的加深、扩大,改善生态环境,有效防止地面沉降、土地沙化、地裂缝的发生。     

干旱引黄灌区地下水位变化特征分析

为研究干旱引黄灌区不同地下水运动带的地下水位变化特征,以甘肃省景电一期灌区为例,利用其1982—2011年实测地下水位数据,采用Mann—Kendall趋势检验法分析了地下水位的年际变化趋势,并根据每15 a逐月的地下水位均值曲线,对地下水位的年内变化特征进行了研究。结果表明:受季节性灌溉、区域地势、人为开采等因素的影响,不同地下水运动带地下水位年际、年内变化趋势存在较大差异;在灌区汇水区域适当发展井灌,有利于土地盐渍化的控制。     

污灌对土壤及地下水环境的影响

污水灌溉在一定程度上能缓解水资源紧缺问题,但如不进行科学管理,又可能造成土壤及地下水环境的污染。本文讨论了污灌污水中的主要污染物特性,结合现有的研究方法,分析了污灌对土壤、地下水和人文环境的影响,并提出了防治污灌影响的具体措施和建议。     

地下水埋深对玉米生长及地下水补给的影响

为研究地下水埋深对玉米生长发育及作物系数的影响,选择宁夏彭阳县红河镇玉米为研究对象,借助试坑模拟对比试验,通过试坑旁的马氏瓶控制地下水位,探讨了地下水埋深对玉米生育期株高、干物质积累量、土壤含水率、产量、地下水补给量和作物系数的影响。结果表明:地下水埋深对玉米生长指标影响显著,地下水埋深为0.9 m时地下水补给量最大为83.5 mm,地下水埋深为1.2 m时地下水补给量最小为54.7 mm。     

地下水污染运移数值模拟及最优估计

本文基于剖开算子法，提出耦合求解地下水流方程和污染运移方程的数值方法，并Ｋａｌｍａｎ滤波技术在地下水污染研究中的应用。计算例表明，本文所提数值方法及Ｋａｌｍａｎ滤波理论的应用，能够避免数值模拟过程中的不良现象，大大提高计算精度，更好地应用于实际工程。     

Potential Clogging and Dissolution Effects During Artificial Recharge of Groundwater Using Potable Water

To avoid the water quality deterioration that are caused by artificial recharge (AR) of groundwater, potable drinking water has been used as one of the source water for AR to control the side effects caused by the over-exploitation of groundwater. Chemical clogging problems can still be caused by certain chemical components, especially Fe and Al, and a lower concentration of these elements can cause a notable decrease in hydraulic conductivity at the top layer of the infiltration medium. Some components in AR source water can be obstructed by the clogging layer, leading to a change in water quality. The accumulation of total suspended solids (TSS) at the clogging layer can cause physical clogging and worsen the degree of chemical clogging. Although clogging and the related change in water quality were the dominant issues that affect the infiltration rate and health risks during the AR process, the dissolution of the aquifer matrix should also be taken into account. This dissolution contributed to not only the hydraulic conductivity of the infiltration medium but also the potential change in water quality during the aquifer recharge, storage and recovery processes.     

Transient-State Analytical Solution for Groundwater Recharge in Triangular-Shaped Aquifers Using the Concept of Expanded Domain

The purpose of this work is to present analytical solution for linearized Boussinesq equation in triangular-shaped aquifers in response to transient recharge from an overlaying basin. Four different configurations of hydrogeological boundary conditions (constant-head and no-flow) are considered. At first, the solutions for the rectangular-shaped aquifers are obtained through the well known image well theory. Then, the concept of expanded domain is utilized to arrive at the solution for the intended triangular domain. The resulting point-recharge solution (Green’s function) facilitates treating any arbitrary shaped recharge basin subjected to spatiotemporal varying recharge. Few examples describing the nature of transient recharge in triangular-shaped aquifers are presented. The investigation of equipotential contour lines and velocity vector fields confirms the validity of the method adopted here. The computed mound profiles are in favourably well agreement with the numerical results obtained by finite element method. Stream flow rates due to recharging are also computed for a single case. Overall, the closed form solutions provide an effective tool in order to conduct sensitivity analysis on various hydrogeological parameters that affect the formation of groundwater mound in triangular-shaped aquifers.     

Modelling Rainfall Runoff Relations Using HEC-HMS and IHACRES for a Single Rain Event in an Arid Region of Jordan

The HEC-HMS and IHACRES rainfall runoff models were applied to simulate a single streamflow event in Wadi Dhuliel arid catchment that occurred on 30–31/01/2008. Streamflow estimation was performed on the basis of an hourly scale. The aim of this study was to develop a new framework of rainfall-runoff model applications in arid catchments by integrating a re-adjusted satellite-derived rainfall dataset (GSMaP_MVK+) to determine the location of the rainfall storm. The HEC-HMS model was applied using the HEC-GeoHMS extension in ArcView 3.3 while the IHACRES is Java-based version model. The HEC-HMS model input data include soil type, land use/land cover, and slope. By contrast, the lumped model IHACRES was also applied, based on hourly rainfall and temperature data. Both models were calibrated and validated using the observed streamflow data set collected at Al-Za’atari discharge station. The performance of IHACRES showed some weaknesses, while the flow comparison between the calibrated streamflow results fits well with the observed streamflow data in HEC-HMS. The Nash-Sutcliffe efficiency (E_f) for the two models was 0.51 and 0.88 respectively.     

Estimation of Groundwater Balance Using Soil-Water-Vegetation Model and GIS

This study concerns the development of a methodology using modern techniques of data generation (Modeling) and interpretation (GIS) to compute groundwater plausibly at regional scale, alternate to previously established norms. The approach is centered on quantitative estimation of two main parameters-input and output. GIS techniques along with soil vegetation model (CropSyst) have been demonstrated for the calculation of groundwater balance components. Using the developed methodology water resources of the Ludhiana district for the period between, 2000 and 2010 were estimated. The temporal changes in water balance components indicated that the major inputs to the hydrologic system are rainfall and canal water and the major out component are evapotranspiration (ET). Multi-annual (2000 to 2010) average of 719 mm rainfall, 88 mm canal water, 74 mm of groundwater inflow, with annual loss 974 mm as ET, caused 123 mm of net negative groundwater recharge in Ludhiana district. The annual computed rise/fall with the developed methodology closely matched the observed values.     

河套灌区节水改造对地下水环境的影响

选择磴口、杭后、临河、五原、前旗和中旗为研究区,分析节水改造工程实施前后灌区地下水环境的变化。结果表明:节水改造后,灌区大部分地区的地下水埋深呈增大趋势,增大幅度为0.07~0.80 m;灌区生育期地下水矿化度(除临河研究区外)呈增大趋势,上游研究区地下水矿化度增大约20%,中下游研究区地下水矿化度增大约60%。     

Analysis of Irrigation Needs Using an Approach Based on a Bivariate Copula Methodology

The problem of drought probability has been investigated by several authors, who have usually analysed droughts using various drought indices such as the Standard Precipitation Index. Various aspects of time series of such indices (intensity, severity and duration) were investigated by several authors using a copula method. Because such analysis is based on only one basic climatic variable, this paper addresses a different approach, i.e., joint analysis of the severity and duration of the most demanding potential annual irrigation periods by a bivariate copula method. Characteristics of these periods are derived from both temperature and precipitation. Maximum annual duration of the potential irrigation period and corresponding rainfall deficit were inferred from these basic variables as inputs to two-dimensional probability analysis by the copula method, because this offers more direct answers to questions of irrigation needs. Results indicate the suitability of the proposed method for analysis of irrigation needs, with greater benefits than the typical one-dimensional analysis of individual climatic variables. A case study for testing the method was done for southwestern Slovakia, for which the frequency of irrigation needs was estimated. Example results indicate that every second year, a one-month period can be expected in which temperatures are >25^°C and there is a moisture deficit of ～30 mm. Even more significant periods of drought can be expected, for example, with a 5 or 10-year return period. These phenomena significantly damage agriculture yields, so requirements for irrigation structures in the study area are indicated by the proposed method.     

Three Dimensional Conceptualisation of Hydrogeological Environment to Underpin Groundwater Management in Irrigation Area

Australian irrigated agriculture utilises about 70?% of all water used in the country, 21?% of which is derived from groundwater. Sustainability for irrigated agriculture also depends on keeping the watertables at a safe level below the rootzone to avoid salinisation and reduction in crop yields. There is a vital need to understand groundwater and aquifer systems and their roles in the sustainability of irrigated agriculture in order to manage groundwater properly. This study builds on the previous hydrogeological and groundwater investigations of the Coleambally Irrigation Area (CIA) in New South Wales of Australia. It presents a new approach which systematically characterises regional hydrogeological environment using a three-dimensional (3-D) conceptual framework developed in ArcGIS. The 3-D hydrological conceptualisation of the CIA has integrated disparate sources of data into a coherent knowledge base for a better visualisation of hydrogeological characteristics and a comprehensive analysis of groundwater flow and aquifers. As an application example, the model was used to develop cross-sectional models of the area and to estimate regional-scale net recharge. The results have provided a basis for the numerical modelling and added values to procedures which underpin irrigation system management investment decisions through improving the understanding of hydrogeology underlying the area and creating an action-oriented dialogue among stakeholders.     

Identification of Potential Sites for Groundwater Recharge Using a GIS-Based Decision Support System in Jazan Region-Saudi Arabia

In arid and semi-arid environments, the amount of recharge received by aquifers is far more critical to the sustainable use of water than it is in humid regions. Groundwater recharge (GWR) is critical to maintain the abundance of groundwater. In the present study, suitable areas for GWR in Jazan region have been identified by using a GIS-based decision support system (DSS). The DSS was implemented to obtain suitability maps and to evaluate the existing GWR in the study area. The DSS inputs comprised maps of rainfall surplus, slope, potential runoff coefficient, land cover/use and soil texture. The spatial extents of GWR suitability areas were identified by a hierarchical process analysis that considered five layers. The model generated a GWR map with four categories of suitability: excellent, good, moderate and poor and unsuitable. The spatial distribution of these categories showed that 50.5 and 31 % of the study area was classified as excellent and good for GWR, respectively, while 16 and 2.5 % of the area were classified as moderate and poor and unsuitable, respectively. Most of the areas with excellent to good suitability have slopes of between 4 and 8 % and are intensively cultivated areas. The major soil type in the excellent to good areas is loamy sand, followed by silt loam, and the rainfall in these areas ranges from 100 to 270 mm. The locations of existing GWR dams were compared with the locations indicated on the generated suitability map using the proximity analysis tool in ArcGIS 10.1. Most (75 %) of the existing GWR structures that were categorised as successful were within the excellent and good areas, followed by moderately suitable (25 %).     

Estimation of Regional Sub-Daily Rainfall Ratios Using SKATER Algorithm and Logistic Regression

Developing Intensity-Duration-Frequency (IDF) curves is a paramount input in stormwater systems design. To construct these IDF curves, rainfall records at sub-daily durations, provided by continuous rainfall recorders, are required; however, these recorders are seldom available in many locations of interest. To fill this gap, available meteorological and topographical information for a study area in Saudi Arabia are investigated to get an estimate of the ratios of sub-daily rainfall depths to the 24-h depths (sub-daily ratios or SDRs), via applying the following methodology. A spatially constrained regionalization approach is implemented, using the SKATER algorithm, based on 60 gauging stations, to form regions of contiguous stations, based on the similarities of their SDRs. Four different regions are formed, where each region shows consistent SDRs; yet distinctly different from other regions. Subsequently, a multinomial logistic regression model is built and trained, with commonly available meteorological and topographical information as explanatory variables, to determine to which region a specific location belongs. The model is validated based on a hold-out validation method and assessed through confusion matrix statistics to evaluate the model performance. The model shows high performance in predicting the correct regional SDR and it is extended to produce a gridded map covering ungauged areas. Based on this procedure, one can develop the IDF curve for any location within the study area, even if there is no rainfall recorder in that location.