Using combined AHP–genetic algorithm in artificial groundwater recharge site selection of Gareh Bygone Plain,Iran

Flood spreading is one of the suitable strategies to control and benefit from floods which in turn improve the groundwater recharge, makes soil more fertile, and increases nutrients in soil. It is also a method for reusing sediment, which is usually wasted. Thus, selection of suitable areas for flood spreading and directing the flood water into permeable formations are amongst the most effective strategies in flood spreading projects. Having combined analytic hierarchy process (AHP) of multi-criteria decision analysis and genetic algorithm (GA) of artificial intelligence approaches, this paper addresses the problem of finding the most suitable area location for flood spreading operation in the Gareh Bygone Plain of Iran. To this end, the nine effective geodata layers including slope, alluvium thickness, geology, morphology, electrical conductivity, land use, drainage density, aquifer transmissivity, and elevation were prepared in geographic information system environment. This stage was followed by elimination of the exclusionary areas for flood spreading while determining the potentially suitable ones. Having closely examined the potentially suitable areas using the proposed methodology, the land suitability map for flood spreading was produced. The AHP and GA were used for ranking all the alternatives and weighting the criteria involved, respectively. The results of the study showed that most suitable areas for the artificial groundwater recharge are located in Quaternary Qft ₂ and Qsf geologic units and in morphological units of pediment and Alluvial fans with slopes not exceeding 2 %. Finally, further evidence for the acceptable efficiency of the integrated AHP–GA method in locating most suitable flood spreading areas have been provided by such significant spatial coincidence between the produced map and the control areas located near Kowsar research station, where the earlier flood spreading projects were successfully performed.     

Delineation of groundwater recharge zones and identification of artificial recharge sites in West Medinipur district,West Bengal,using RS,GIS and MCDM techniques

Artificial recharge plays a pivotal role in the sustainable management of groundwater resources. This study proposes a methodology to delineate artificial recharge zones as well as to identify favorable artificial recharge sites using integrated remote sensing (RS), geographical information system (GIS) and multi-criteria decision making (MCDM) techniques for augmenting groundwater resources in the West Medinipur district of West Bengal, India, which has been facing water shortage problems for the past few years. The thematic layers considered in this study are: geomorphology, geology, drainage density, slope and aquifer transmissivity, which were prepared using IRS-1D imagery and conventional data. Different themes and their corresponding features were assigned proper weights based on their relative contribution to groundwater recharge in the area, and normalized weights were computed using the Saaty’s analytic hierarchy process (AHP). These thematic layers were then integrated in the GIS environment to delineate artificial recharge zones in the study area. The artificial recharge map thus obtained divided the study area into three zones, viz., ‘suitable,’ ‘moderately suitable’ and ‘unsuitable’ according to their suitability for artificial groundwater recharge. It was found that about 46% of the study area falls under ‘suitable’ zone, whereas 43% falls under the ‘moderately suitable’ zone. The western portion of the study area was found to be unsuitable for artificial recharge. The artificial recharge zone map of the study area was found to be in agreement with the map of mean groundwater depths over the area. Furthermore, forty possible sites for artificial recharge were also identified using RS and GIS techniques. Based on the available field information, check dams are suggested as promising artificial recharge structures. The results of this study could be used to formulate an efficient groundwater management plan for the study area so as to ensure sustainable utilization of scarce groundwater resources.     

Impact of flash flood recharge on groundwater quality and its suitability in the Wadi Baysh Basin,Western Saudi Arabia: an integrated approach

An integrated approach was used to evaluate the impact of flash flood recharge on groundwater quality and its suitability for drinking, irrigation, livestock and poultry uses in the Wadi Baysh Basin, Western Saudi Arabia. Analyses of 182 groundwater samples, collected from the study area before and after a flash flood (FF) event, show that the average concentrations of TDS, Mg, Na, Cl, NO₃ and EC decreased significantly after the event. The major water types (mixed CaMgCl, NaCl and CaCl) indicate that the infiltration of surface water from FF recharge has a great influence on groundwater chemistry. Drinking water suitability maps, created using WHO standards, indicate that wells located in the upstream region are suitable for drinking despite their high TDS and total hardness (TH) values. Groundwater in the coastal region is unsuitable due to its high salinity, high TH and high concentrations of major ions. The suitability of groundwater for irrigational use was assessed using salinity, sodium adsorption ratio, bicarbonate hazard, residual sodium carbonate, Kelly’s ratio, magnesium hazard, sodium percentage and permeability index values, which indicated that groundwater in the study region is suitable for most soils and crops. After FF, groundwater quality is improved by dilution, especially in the downstream region. USSL classification shows that the majority of the water samples are in the C3S1, C4S2, and C3S2 classes and are therefore suitable for the irrigation of salt-tolerant crops. Irrigational suitability maps suggest that wells in the upstream region are suitable for irrigation, whereas wells located near to the coast are unfit for irrigation. This study implies that construction of check dams in the dry valleys (wadies) may improve the groundwater quality in the area.     

Site selection and cost-benefit analysis for artificial recharge in the Baghmalek plain, Khuzestan Province, southwest Iran

Available hydrogeological data for the Baghmalek aquifer, southwest Iran, suggest that in order to counter progressive depletion of groundwater, but at the same time meet the growing demand on groundwater resources, artificial recharge should be considered. The success of artificial recharge schemes requires the integration of many types of data and information. The prime prerequisite in establishing an artificial recharge scheme using the surface spreading technique is identification of a suitable site. Therefore, an integrated investigation, including a detailed assessment of surface and sub-surface geology, and hydrogeological surveys were undertaken. The potential of harvesting storm waters, considering their quality and suspended loads, has been evaluated. Using this background, three sites (including basins and check dam) for artificial recharge are suggested in the north and northeast of the area, where the thickness of coarse alluvium is greatest. On the basis of the collected data, (1) the rate of recharge that can be achieved at the three sites is approximately 2.2 million m³ per year, (2) the cost–benefit ratio is 1:1.32, and (3) the analysis suggests that the project could recover the investment within 3 years.     

GIS based groundwater modeling study to assess the effect of artificial recharge: A case study from Kodaganar river basin,Dindigul district,Tamil Nadu

Groundwater is a dynamic and replenishable natural resource. The numerical modeling techniques serve as a tool to assess the effect of artificial recharge from the water conservation structures and its response with the aquifers under different recharge conditions. The objective of the present study is to identify the suitable sites for artificial recharge structures to augment groundwater resources and assess its performance through the integrated approach of Geographic Information System (GIS) and numerical groundwater modeling techniques using MODFLOW software for the watershed located in the Kodaganar river basin, Dindigul district, Tamil Nadu. Thematic layers such as geology, geomorphology, soil, runoff, land use and slope were integrated to prepare the groundwater prospect and recharge site map. These potential zones were categorized as good (23%), moderate (54%), and poor (23%) zones with respect to the assigned weightage of different thematic layers. The major artificial recharge structures like percolation ponds and check dams were recommended based on the drainage morphology in the watershed. Finally, a threelayer groundwater flow model was developed. The model was calibrated in two stages, which involved steady and transient state condition. The transient calibration was carried out for the time period from January 1989 to December 2008. The groundwater model was validated after model calibration. The prediction scenario was carried out after the transient calibration for the time period of year up to 2013. The results show that there is 15 to 38% increase in groundwater quantity due to artificial recharge. The present study is useful to assess the effect of artificial recharge from the proposed artificial structures by integrating GIS and groundwater model together to arrive at reasonable results.     

Application of remote sensing and GIS for delineating groundwater recharge potential zones of Kovilpatti Municipality,Tamil Nadu using IF technique

During the last three decades, remotely sensed data (both satellite images and aerial photographs) have been increasingly used in groundwater exploration and management exercises. An integrated approach has been adopted in the present study to delineate groundwater recharge potential zones using RS and GIS techniques. IRS-1C satellite imageries and Survey of India toposheets are used to prepare various thematic layers viz. geology, soil, land-use, slope, lineament and drainage. These layers were then transformed in to raster data using feature to raster converter tool in ArcGIS 9.3 software. The raster maps of these factors are allocated a fixed score and weight computed from Influencing Factor (IF) technique. The weights of factors contributing to the groundwater recharge are derived using aerial photos, geology maps, a land use database, and field verification. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater recharge zones within the study area. Then these potential zones were categories as ‘high’, ‘moderate’, ‘low’, ‘poor’. The resulted map shows that 19 % of the area has highest recharge potential, mainly confined to buried pediplain, agriculture land-use and river terraces (considerable amount of precipitated water percolates into subsurface), 28 % of the area has moderate groundwater recharge potentiality and rest of the area has low to poor recharge potentiality. The residual hills and linear ridges with steep slopes are not suitable for artificial recharge sites. Finally, 13 % of total average annual precipitated water (840 mm) percolates downward and ultimately contributes to recharge the aquifers in the Kovilpatti Municipality area. The paper is an attempt to suggest for maintaining the proper balance between the groundwater quantity and its exploitation.     

Identification of suitable sites for groundwater recharge in Awaspi watershed using GIS and remote sensing techniques

Groundwater is a valuable natural resource for drinking, domestic, livestock use, and irrigation, especially in arid and semi-arid regions like the Garmiyan belt in Kurdistan region. The Awaspi watershed is located 50 km east of Kirkuk city, south Kurdistan, Iraq; and covers an area of 2146 km². The paper presents result of a study aimed at: (1) mapping and preparing thematic layers of factors that control groundwater recharge areas, and (2) determination of sites suitable for groundwater recharge. We used available data such as geological map, groundwater depth map, digital elevation model (DEM), Landsat 8 imagery, and tropical rainfall measuring mission (TRMM) data for this study. These data, supplemented by slope features, lithology, land use land cover, rainfall, groundwater depth, drainage density, landform, lineament density, elevation and topographic position index, were utilized to create thematic maps to identify suitable areas of groundwater recharge, using GIS and remote sensing techniques. Analytic hierarchy process (AHP) was applied to weight, rank, and reclassify these maps in the ArcGIS 10.3 environment, to determine the suitable sites for groundwater recharge within the Awaspi watershed. Fifty-five percent of the total area of the watershed was found to be suitable for groundwater recharge; whereas 45% of the area was determined to have poor suitability for groundwater recharge, but can be used for surface water harvesting.     

Mapping of hard rock aquifer system and artificial recharge zonation through remote sensing and GIS approach in parts of Perambalur District of Tamil Nadu,India

Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,India.This district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater Board.To raise the groundwater level,suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present study.To this end,various thematic maps concerning lithology,soil,geomorphology,land use,land cover,slope,lineament,lineament density,drainage,drainage density and groundwater depth level were prepared.Fissile hornblende gneiss(244 km^2)covered most of the study area followed by charnockites(68 km^2).Structural hills and rocky pediments characterize the major geomorphological features in the targeted area,and are followed by deep moderated pediments.The area is mostly used as crop and fallow land,followed by scrub land and deciduous forest.In the study area,the slopes are predominantly very gentle(142 km^2)and nearly level(66 km^2)ones.Besides,Groundwater level data of 58 wells have been generated,in which the minimum and maximum depth were 3 and 28 m respectively.Integration under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank methods.Integrated output performances were classified into very poor,poor,moderate,good and excellent categories.All these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge sites.Hard rock fractures were mapped as lineaments from satellite images,and besides that,rose diagram was also generated to find out the trend of the fracture.Furthermore,fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from lineaments.The present study significantly brought up a few areas such as Ammapalayam,Melapuliyur,Senjeri and around Siruvachur for artificial recharge.     

Mapping of hard rock aquifer system and artificial recharge zonation through remote sensing and GIS approach in parts of Perambalur District of Tamil Nadu,India

Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km2 in parts of the Perambalur District, Tamil Nadu, India. This district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater Board. To raise the groundwater level, suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present study. To this end, various thematic maps concerning lithology, soil, geomorphology, land use, land cover, slope, lineament, lineament density, drainage, drainage density and groundwater depth level were prepared. Fissile hornblende gneiss (244 km2) covered most of the study area followed by charnockites (68 km2). Structural hills and rocky pediments characterize the major geomorphological features in the targeted area, and are followed by deep moderated pediments. The area is mostly used as crop and fallow land, followed by scrub land and deciduous forest. In the study area, the slopes are predominantly very gentle (142 km2) and nearly level (66 km2) ones. Besides, Groundwater level data of 58 wells have been generated, in which the minimum and maximum depth were 3 and 28 m respectively. Integration under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank methods. Integrated output performances were classified into very poor, poor, moderate, good and excellent categories. All these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge sites. Hard rock fractures were mapped as lineaments from satellite images, and besides that, rose diagram was also generated to find out the trend of the fracture. Furthermore, fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from lineaments. The present study significantly brought up a few areas such as Ammapalayam, Melapuliyur, Senjeri and around Siruvachur for artificial recharge.     

Comparison of the performance of power law and probability distributions in the frequency analysis of flood in Dez Basin,Iran

Determination of the return period of design flood depends on the nature of the project and the consequences of the flood and is based on economic criteria, human casualties, and hydrological factors. Underestimation of flood might result in casualties and economic damages, while the overestimation leads to capital waste. Therefore, in this research, the flood frequency analysis of Dez Basin, Iran was conducted within the period of 1956–2012 using power law approach together with ordinary distributions, including normal, log normal, Pearson type III, exponential, gamma, generalized extreme value, Nakagami, Rayleigh, logistic, generalized logistic, generalized Pareto, and Weibull distributions. The power law comes from the fractal nature of earth science phenomena such as precipitation and runoff. Accordingly, in this research the partial duration flood series of five hydrometric stations in Dez Basin were extracted using power law with the intervals of 7, 14, 30, and 60 days and then compared with the annual maxima. The results indicated that the annual maxima were not suitable for frequency analysis of the flood in Dez Basin, and the 30-day partial duration series obtained from the power law has a better correspondence with the flow and properties of the Dez Basin. The independence and stationarity of the 30-day partial duration series were examined by Wald–Wolfowitz test, confirming the independence of the considered series. Next, the power distribution and the typical statistical distributions were fitted onto the data of the flood in Dez Basin, with the performance of each distribution being investigated using normalized root-mean-square error and Nash–Sutcliffe criteria. The results revealed that in the SDZ and TPB stations, power distribution had a better performance than other considered distributions. Moreover, in the SDS, TPS, and TZ stations the power distribution stood in the second rank in terms of the best distribution. As the performance of power distribution in the estimation of the flood in Dez Basin has been very satisfactory and calculation of its parameters and its application is easier than ordinary probability distributions, thus it can be suggested as the superior distribution for flood frequency analysis in Dez Basin.     

http://www.sciencedirect.com/science/article/pii/S1674987115000390

The demand for fresh water in Hambantota District, Sri Lanka is rapidly increasing with the enormous amount of ongoing development projects in the region. Nevertheless, the district experiences periodic water stress conditions due to seasonal precipitation patterns and scarcity of surface water resources.Therefore, management of available groundwater resources is critical, to fulfil potable water requirements in the area. However, exploitation of groundwater should be carried out together with artificial recharging in order to maintain the long term sustainability of water resources. In this study, a GIS approach was used to delineate potential artificial recharge sites in Ambalantota area within Hambantota. Influential thematic layers such as rainfall, lineament, slope, drainage, land use/land cover, lithology, geomorphology and soil characteristics were integrated by using a weighted linear combination method. Results of the study reveal high to moderate groundwater recharge potential in approximately 49% of Ambalantota area.     

Spatial and temporal constraints on regional-scale groundwater flow in the Pampa del Tamarugal Basin,Atacama Desert,Chile

Aquifers within the Pampa del Tamarugal Basin (Atacama Desert, northern Chile) are the sole source of water for the coastal city of Iquique and the economically important mining industry. Despite this, the regional groundwater system remains poorly understood. Although it is widely accepted that aquifer recharge originates as precipitation in the Altiplano and Andean Cordillera to the east, there remains debate on whether recharge is driven primarily by near-surface groundwater flow in response to periodic flood events or by basal groundwater flux through deep-seated basin fractures. In addressing this debate, the present study quantifies spatial and temporal variability in regional-scale groundwater flow paths at 20.5°S latitude by combining a two-dimensional model of groundwater and heat flow with field observations and δ¹⁸O isotope values in surface water and groundwater. Results suggest that both previously proposed aquifer recharge mechanisms are likely influencing aquifers within the Pampa del Tamarugal Basin; however, each mechanism is operating on different spatial and temporal scales. Storm-driven flood events in the Altiplano readily transmit groundwater to the eastern Pampa del Tamarugal Basin through near-surface groundwater flow on short time scales, e.g., 10⁰–10¹ years, but these effects are likely isolated to aquifers in the eastern third of the basin. In addition, this study illustrates a physical mechanism for groundwater originating in the eastern highlands to recharge aquifers and salars in the western Pampa del Tamarugal Basin over timescales of 10⁴–10⁵ years.     

Assessment of artificial aquifer recharge potential in the Kucuk Menderes River Basin, Turkey

The Kucuk Menderes River Basin in western Turkey has been facing continuous groundwater-level decline for decades. Previous studies have suggested that, to avoid aquifer depletion in the basin, artificial recharge structures should be constructed. To assess artificial aquifer recharge potential in one of the subbasins, a two-dimensional (2-D) groundwater model was set up using SEEP/W software. The material functions and parameters used in the model for both saturated and unsaturated conditions were taken from previous studies. The model has been calibrated under transient conditions. The excess runoff volume that could be collected in the recharge basins was estimated from flood frequency analysis. Various scenarios were simulated to observe the change in groundwater level and storage with respect to different exceedance probabilities. Simulation results suggest that a significant increase in groundwater storage is achieved by applying surface artificial-recharge methods. In addition to the recharge basins, to reinforce the effect of artificial recharge, simulations are repeated with underground dam construction at the downstream side of the basin. Although groundwater storage is increased with the addition of the dam, the increase in groundwater storage was not sufficient to warrant the construction.     

Mapping favorable groundwater potential recharge zones using a GIS-based analytical hierarchical process and probability frequency ratio model:A case study from an agro-urban region of Pakistan

In Punjab(Pakistan),the increasing population and expansion of land use for agriculture have severely exploited the regional groundwater resources.Intensive pumping has resulted in a rapid decline in the level of the water table as well as its quality.Better management practices and artificial recharge are needed for the development of sustainable groundwater resources.This study proposes a methodology to delineate favorable groundwater potential recharge zones(FPRI) by integrating maps of groundwater potential recharge index(PRI) with the DRASTIC-based groundwater vulnerability index(VI).In order to evaluate both indexes,different thematic layers corresponding to each index were overlaid in ArcGIS.In the overlay analysis,the weights(for various thematic layers) and rating values(for sub-classes) were allocated based on a review of published literature.Both were then normalized and modified using the analytical hierarchical process(AHP) and a frequency ratio model respectively.After evaluating PRI and FPRI,these maps were validated using the area under the curve(AUC) method.The PRI map indicates that 53% of the area assessed exists in very low to low recharge zones,22% in moderate,and 25% in high to excellent potential recharge zones.The VI map indicates that 38% of the area assessed exists in very low to low vulnerability,33% in moderate,and 29% in high to very high vulnerability zones.The FPRI map shows that the central region of Punjab is moderately-to-highly favorable for recharge due to its low vulnerability and high recharge potential.During the validation process,it was found that the AUC estimated with modified weights and rating values was 79% and 67%,for PRI and VI indexes,respectively.The AUC was less when evaluated using original weights and rating values taken from published literature.Maps of favorable groundwater potential recharge zones are helpful for planning and implementation of wells and hydraulic structures in this region.     

Identification of potential groundwater recharge zones in Vaigai upper basin,Tamil Nadu,using GIS-based analytical hierarchical process (AHP) technique

Groundwater recharge is an important process for the management of both surface and subsurface water resources. The present study utilizes the application of analytical hierarchical process (AHP) on geospatial analysis for the exploration of potential zones for artificial groundwater recharge along Vaigai upper basin in the Theni district, Tamil Nadu, India. The morphology of earth surface features such as geology, geomorphology, soil types, land use and land cover, drainage, lineament, and aquifers influence the groundwater recharge in either direct or indirect way. These thematic layers are extracted from Landsat ETM+ image, topographical map, and other collateral data sources. In this study, the multilayers were weighed accordingly to the magnitude of groundwater recharge potential. The AHP technique is a pair-wise matrix analytical method was used to calculate the geometric mean and normalized weight of individual parameters. Further, the normalized weighted layers are mathematically overlaid for preparation of groundwater recharge potential zone map. The results revealed that 21.8 km² of the total area are identified as high potential for groundwater recharge. The gentle slope areas in middle-east and central part have been moderately potential for groundwater recharge. Hilly terrains in south are considered as unsuitable zone for groundwater recharge processes.     

Alluvial aquifer recharge enhanced by a natural dam: feasibility assessment based on multidisciplinary characterization (Khuzestan,Southwest Iran)

In the Kushkak Valley (Khuzestan, Southwest Iran) an anticlinal structure has partially impounded an ephemeral stream. This natural impounded area has been chosen for an artificial recharge site due to its current rate of recharge, capability to store water and favorable situation for the construction of man-made barriers to stream flow. The aquifer to be recharged is the Kushkak unconfined aquifer which consists of medium to coarse-grained alluvial deposits that overlie consolidated conglomerate rock. In this semi-arid area with infrequent relatively heavy falls of rain, alluvial aquifer recharge can be an important process that sustains shallow, over-exploited groundwater bodies. In this investigation a multidisciplinary approach including: hydrometerological studies, and a detailed hydrogeochemical survey, have been carried out. Other essential prerequisite parameters for the scheme were also taken into account to determine the suitability of this location for groundwater artificial recharge. The assessment has brought out that (1) the proposed reservoir will conserve a major part of the water being lost, (2) annual runoff of about 0.27 MCM can be injected into the aquifer through recharge from impounded water, (3) hydrochemical data from surface water and from the Kushkak aquifer water demonstrates that dilution and change in compositional trend in the groundwater proximal to the impounded alluvial bed areas would be expected based on the infiltration capacity of this site, and (4) cost–benefit ratio of the project is 1:2 and it is assumed to recover the investment within six years.     

拓扑克里格法与普通克里格法在区域洪水频率分析中的比较研究

依据北江(珠江流域支流)流域6个水文测站年最大洪峰流量资料,分别用Top-kriging(拓扑克里格法)和普通克里格法进行区域洪水频率估计。采用均方根误差作为频率分布线型拟合优度指标。运用线性矩法进行单站洪水频率分析,确定10、50、100、1000年一遇设计洪水值。在此基础上,从Topkriging和普通克里格法设计洪水估计不确定性和相对线性矩法单站洪水频率的估计误差两个方面比较Top-kriging和普通克里格法。结果表明:(1)Top-kriging法是更好的线性无偏估计,相比普通克里格法更适合于区域洪水频率估计;(2)Top-kriging法设计洪水估计不确定性明显小于普通克里格法;(3)Top-kriging法设计洪水估计结果更接近线性矩法单站洪水频率分析结果。     

Integrative approach of RS and GIS in characterization of land suitability for agriculture: a case study of Darna catchment

Land elements like slope, soil depth, land use/land cover, water holding capacity, soil texture, soil erosion, elevation, potential of hydrogen, etc. determine the suitability for agriculture. Land suitability analysis is a one of the methods of assessment of detecting inherent capacities, potential and suitability levels of the lands for agriculture, and was utilized with the same land elements in this study. A multi-criterion decision making approach using IRS P6 LISS-IV satellite dataset within a GIS environment was used to identify suitable areas for agriculture in the Darna catchment. Experts’ opinions, literature review, and correlation technique were used to decide influencing criteria, assign scores to sub-criteria, and judgment formation in pairwise comparison matrix. All thematic layers of criteria were integrated with each other in GIS using the weighted overlay technique and generated agriculture suitability map into four classes according to FAO. About 23% of the area is under agriculture in the study region. This area can extend up to 69% under agriculture converting fallow land, scrub land, and sparse forest according to soil qualities with suitability levels, i.e., highly suitable (19%), moderately suitable (16%), and marginally suitable (34%). About 31% (19,219 ha) of reviewed area are classified in the class permanently “not suitable” for agriculture. Moderately and marginally suitable land requires the irrigation facility for efficient agriculture. This study emphasizes that about 46% area has potential as agriculture land and it will help improve the financial condition of the farmers.     

Groundwater recharge in Pleistocene sediments overlying basalt aquifers in the Palouse Basin, USA: modeling of distributed recharge potential and identification of water pathways

Groundwater levels in basalt aquifers around the world have been declining for many years. Understanding water pathways is needed for solutions like artificial drainage. Water supply in the Palouse Basin, Washington and Idaho, USA, primarily relies on basalt aquifers. This study presents a combination of modeling and field observations to understand the spatial distribution of recharge pathways in the overlying Pleistocene sediments. A spatially distributed model was used to quantify potential recharge rates. The model shows clearly that recharge predominantly occurs through non-argilic soils and soils that are not underlain by fine-grained sediments, i.e. the upper area of the watershed. A field survey was conducted to determine recharge pathways from this area. It revealed 83 ?perennial springs. Drillings near springs showed connection of coarse-grained layers within the fine-grained Sediments of Bovill to these springs. Such layers, with streambed-like features, act as paleo-channels. Water from one of these coarse-grained layers had a similar electrical conductivity (200? ??S? cm^?C1) to water from a downstream perennial spring, also suggesting the existence of a lateral conduit for deep percolation water.