Assessment of Waterlogging in Sriram Sagar Command Area,India, by Remote Sensing

Waterlogging is becoming a serious problem in irrigated command areas of India. The study area is the Sriram Sagar command, which is about 120 km north of Hyderabad. An attempt has been made to make an assessment of the waterlogged area and those areas sensitive to waterlogging during the pre and post monsoon periods in the Sriram Sagar command using remorely sensed and field data. Indian Remote Sensing Satellite (IRS-1A-LISS-II) digital data (Computer Compatible Tapes) of 12 April and 6 October 1989, were analysed to assess the areas affected by waterlogging and those areas sensitive to waterlogging. The validation of the IRS-derived waterlogged areas, was done using available water table depth data and other field information. The results obtained from this study indicate that in April and October 1989, areas of some 388 and 540 km2 were waterlogged and about 698 and 802 km2, respectively, were sensitive to waterlogging (where the water table lies between 1 to 2 m, respectively, below the ground surface. It is suggested that periodic assessment of waterlogging, using remotely sensed data, should be carried out in the Sriram Sagar command. The IRS data have been proved to be very succesful for the assessment of waterlogging. Density slicing and principal component analysis are useful techniques in making an assessment of waterlogged areas in irrigated command areas.     

Integrated Biophysical and Economic ModellingFramework to Assess Impacts of Alternative Groundwater Management Options

We developed an integrated biophysical and economic modeling framework to assess impact of various groundwater management options on seawater intrusion and waterlogging and ultimate impact on sugarcane profitability in a coastal region of North Queensland, Australia. The modelling framework used the output of a groundwater management flow model (waterlogged and seawater intruded areas) and a crop simulation model (simulated crop yield) and maximised the net revenue in a mathematical programming (optimisation) model. The framework determined the economically optimal level of water use on different soil types and in different management regimes and estimated impact of seawater intrusion and waterlogging on net revenue of growing sugarcane in two neighbouring water board areas (North Burdekin Water Board – NBWB and South Burdekin Water Board – SBWB). In NBWB, the predicted aggregate net revenue was highest ($19.95 million) when groundwater use was also highest (70%) while predicted aggregate net revenue was lowest when groundwater use was also lowest. In SBWB, the predicted aggregate net revenue was highest ($23 million) when groundwater use was relatively low (61%). The predicted aggregate net revenues of all the management options were higher in SBWB than NBWB.     

Mapping of Conjunctive Water Use Productivity Pattern in an Irrigation Command Using Temporal IRS WiFS Data

Irrigated agriculture in many areas of the world is currently being practiced from multiple water sources such as precipitation, canal, wetlands, ground aquifer, etc. This study highlights the use of high temporal remote sensing data [IRS-1D; Wide Field Sensor (WiFS), 188-m resolution] to assess conjunctive water use pattern and its productivity in the 6 Main Canal command of Damodar Irrigation Project West Bengal, India. In this command three sources of water (canal water, groundwater and wetland) were used for the rice growing system during the summer season. A multi-date (ten dates, two bands) image stack was prepared. Using this image stack and an unsupervised classification (Fuzzy k-means) backed by space–time spiral curve (ST-SCs) technique, canal release and wetlands information was used to prepare irrigated classes (canal, groundwater or wetlands) map for summer 2000. ST-SCs have been used to analyze temporal WiFS data to continuously monitor class dynamics over time and space and to determine class separability (different types of irrigated-classes) at various time periods within the season. Results showed that the area under agriculture, non-agriculture and water were 81%, 18.5% and 0.5%, of the total area respectively. While, groundwater, canal water and wetland irrigated rice were 67.6%, 25.6% and 6.8%, respectively out of the total agriculture area. Classification results found to have more than 89.3% overall accuracy for broad land cover, while sub-classes of rice i.e. irrigated classes found have reasonably good accuracy of 85.7%. A productivity index (LAI/water-requirement) was also developed. Productivity index was high for the wetland and groundwater irrigated rice as compared to the rice irrigated through canal water. These results were weighed against the observed yield data.     

Nitrate in the Water-Supply Wells in the Mancha Oriental Hydrogeological System (SE Spain)

This study determines the spatial and temporal distribution of nitrate content within the water-supply wells in the Mancha Oriental System (MOS) for the period 1998–2003 and presents an example of the multiple nitrate pollution sources in the El Salobral–Los Llanos Domain (SLD, southwestern Albacete). The groundwater resources of the MOS are used to maintain approximately 800 km² of irrigated crops and are the sole water supply for a total population of 275,000 inhabitants. The average nitrate content varies from <0.5 mg l^− 1 (detection limit) to 125 mg l^− 1. In some areas of the MOS statistical analyses show a growing tendency between 2001 and 2003. Nitrate content shows a heterogeneous spatial distribution but the highest levels can be associated with large areas of irrigated crops. However, there are also points in which nitrate has been detected in significant quantities which are not found to be spatially linked to this kind of crop. The presence of nitrate in these areas can be explained considering other sources of pollution, such us wastewater, or due to pollutant transport from contaminated areas through groundwater flow in a multiple-layered karstic aquifer. These results lead necessarily to reconsider the agricultural-derived nitrate as the sole source of pollution and to analyze the effectiveness of the current wastewater treatment practices from effluents in the MOS.     

Comparison of Different Indicators for Groundwater Contamination by Seawater Intrusion on the Lebanese Coast

In order to evaluate the state of groundwater salination by seawater intrusion on the Lebanese coast, the region of Choueifat–Rmeyle, situated in the south of Mount-Lebanon, was chosen as a study zone. Overall, six wells were chosen and water sampling was done for three years starting from 1999 till 2002. Sampling was done on a monthly basis for ten months per year, from July till April. A complete physico-chemical analysis was done for all the water samples taken. Seawater intrusion in the Choueifat-Rmeyle region was studied through the interrelations between the chemical and physical constituents of groundwater. Results showed that the regions of Choueifat, Jiye and Rmeyle were subject to seawater intrusion. This intrusion was directly and simultaneously related to the pumping period and intensity but weakly linked to the quantity of rainfall. It was also related to the geologic nature of the study area. Furthermore, the actual intrusion in the study zone increases the already existing salinity problems. The salinity rates of wells water oscillated between 0.7 dS/m and 5.5 dS/m with the majority above 2 dS/m. This is leading to intolerable levels of water and soil salinity, inadequate for the cultivation of many crops, thus threatening their growth and production and reducing the agrodiversity in the region.     

Estimating Groundwater Withdrawal in Poorly Gauged Agricultural Basins

A method is presented for estimating the annual groundwater withdrawal based on water balance resulting from surface and groundwater hydrological considerations. The unknown groundwater losses of the aquifer are estimated from the groundwater level fluctuations, the specific yield and the groundwater withdrawal prior to the installation of the irrigation network. The meteorological and hydrometric data are used in the Sacramento hydrological conceptual model for the estimation of the stored groundwater volume, via minimization of the difference between the simulated and measured stream discharge. Following the installation of the network due to poorly kept field records, an initial estimation of the groundwater withdrawal is made based on the fluctuations of the groundwater level, the specific yield, and the annual precipitation. The monthly stored groundwater volume is verified against the volume obtained during the recharge of the basin (November–April). The difference between the groundwater volume and the measured discharge of the basin (May–October) is in agreement with the initial estimation of the groundwater withdrawal. This method is applied successfully in an agricultural basin on the island of Crete, Greece and its novelty lies in the fact that it can be used in basins where groundwater withdrawal is not known or data is incomplete.     

A Dissipative Hydrological Model for the Hotan Oasis (DHMHO)

Various hydrological models have been designed to simulate moisture transformation in the water-cycle system between atmospheric water, surface water, soil water and groundwater. But few have been designed specially for oases in arid desert areas where the ecology and the environment are vulnerable because of unwise water-land resources utilization. In order to analyze the moisture transformation in the Hotan Oasis in the Taklimakan Desert in China, and hence to provide scientific references for the rational exploitation and allocation of the limited water-land resources, for the purpose of ensuring that the vulnerable ecology and environment there can be gradually improved and the social economy there can develop sustainably, a dissipative hydrological model for the Hotan Oasis (DHMHO) was developed. It was an outcome of years of systematic study on the moisture transformation in arid areas and on the water–land conditions in the Hotan Oasis. Based on statistics, DHMHO introduces two empirical equations whereby we dynamically calibrated model parameters with monthly data from year 1971 to 1995. Then the calibrated parameters were used to model the moisture movement from 1996 to 2003 and thereafter rationality check and error analysis were conducted. The error analysis results show that the absolute relative errors between simulated and observed groundwater depth values are almost (11 of 12 points) within 20%, and those in annual watershed outflow simulation are mostly (six of eight points) within 20% with an average annual Nash–Sutcliffe Efficiency Coefficient (NSEC) of 0.80. With DHMHO and IPCC assessment, we also simulated the moisture transformation and dissipation in the Hotan Oasis from the year 2011 to 2020. Results show details of the water resources in the Hotan Oasis in the next decade and hence are expected to provide scientific references for establishing rational exploitation and allocation policies on the local water–land resources in the future.     

Application of GWQI to Assess Effect of Land Use Change on Groundwater Quality in Lower Shiwaliks of Punjab: Remote Sensing and GIS Based Approach

The groundwater resource is a multidimensional concept; it is defined by its location, its occurrence over time, its size, properties, conditions of accessibility, the effort required to mobilize it and therefore, all of which are to be considered in the context of demand. Groundwater, a renewable and finite natural resource, vital for man’s life, social and economic development and a valuable component of the ecosystem, is vulnerable to natural and human impacts. There is a great need for the assessment and monitoring of quality and quantity of groundwater resource required at local level to develop an exact scenario of watershed. In this study qualitative assessment of groundwater was done and a ground water quality index criterion was used to understand the suitability of groundwater for irrigation and drinking purpose in the study area. A GIS based multicriteria analysis was done by assigning weight to different water quality parameters. The water quality was grouped into six classes from very good to unfit for drinking. It was found that the in most part of the study area the water quality varied from moderate to good except in some areas where it is poor to unfit. An assessment of change in landuse and landcover was done from the year 1989 using Landsat data to year 2006 using LISS III satellite data. The change in LULC was correlated with water quality data and it was found that the areas around which rapid urbanisation as well as industrialisation is taking place showed poor to unfit groundwater in terms of quality.     

Groundwater modeling and demarcation of groundwater protection zones for Tirupur Basin – A case study

Groundwater is a renewable resource and has to be protected from contamination. The concept of a zone of protection for areas containing groundwater has been developed and adopted in a number of countries. One such area is Tirupur, (Tamil Nadu, India) which is an arid region and rapid expansion of the textile industry has taken place with no associated development of supporting infrastructure or institutional capacity. Textile production, particularly dyeing and bleaching is water intensive and generates large quantities of effluent. One of the most significant challenges for the Tirupur textile industry today is water for bleaching and disposal of effluent. Demarcation of groundwater protection zones has become necessary to facilitate recharging of the aquifer to meet the water demand. These zones are considered sensitive zones and should be free from activities such as the groundwater over exploitation, effluent discharge and construction of barriers. Groundwater flow for Tirupur Block was simulated using visual MODFLOW version 4.1. The model was run for the year 1998–99 with transient flow condition. Taking June 1998 water level as initial head, the model was run to simulate water level up to May 1999 and validated with the observed data for all the six wells which are distributed over six different zones. The results obtained from the simulation were used to assign the ranks and weights for overlay process in Geomedia environment. The consequent higher index values indicate the sensitivity zone influencing recharge to the aquifer which should be demarcated as groundwater protection zones. This groundwater protection zone will be designated as pollution free zone for better management of the aquife.     

基于数字遥感影像的呼伦湖水量平衡分析

利用多源、多时相的数字遥感影像和呼伦湖周边地区水文气象资料,采用基于卷积神经网络的高分辨率图像重构方法研究了1999—2019年呼伦湖面积、库容变化情况。结果表明:2003—2012年呼伦湖的面积逐年减小,湖泊水量逐年下降,2003—2012年补给呼伦湖的乌尔逊河与克鲁伦河的多年平均径流量分别为1.30亿m³与1.41亿m³,分别只有1991年以前多年平均径流量的21%与24%;而2003—2012年呼伦湖平均水面年蒸发量为17.5亿m³,平均年湖面降水量为3.25亿m³;地下水补给呼伦湖的年平均水量为5.3亿m³,主要来自新生代玄武岩地下水,哈拉哈河源头火山玄武岩地下水通过熔岩管道集中外泄,据此推断补给呼伦湖的地下水来自跨流域的外源水。     

Rainwater Management for Smallholder Irrigation and it’s Impact on Crop Yields in Eastern India

A tank cum open dug well system suitable for plateau region of eastern India has been developed for providing reliable irrigation to croplands. The system comprises of a series of tanks with open dug wells in the recharge zone of the tank that reharvest back the seepage water. Thus, the rainwater remaining in the tank as well as partial seeped water is used for providing round the year full irrigation. This system was evaluated in field in Keonjhar district of Orissa of eastern India with six tanks and five wells in two drainage lines. The total command area of the system of six tanks and five wells in both drainage lines is 23 ha and the total irrigation potential is 44.5 ha. The total cost of the system is US $19,180 making the cost of irrigation resource creation as US $426 per ha which is much less than about $2,220 per ha for major and medium irrigation projects in the last decade of 20th century. The system increased the rice yields from 1.92 t ha^− 1 to a range of 2.25 to 3.8 t ha^− 1 depending upon the package of practices or the amount of inputs. The farmers went for crops in post-monsoon and summer season and the cropping intensity rose to 112% in the first year, 126% in the second year and 132% in the third year. The internal rate of return from the system was 13.4% at the present level of utilization, which is about 2.4% more than the prime-lending rate of Indian banks, and 3.4% more than the lending rate for agricultural purposes.     

Operating experience with and problems of lightning protection for the first domestic 220-kV overhead lines from the lower Svir’ HPP to the Lenénergo

Results of analysis of operating experience with automatic disconnection of the first domestic 220-kV overhead lines from the Lower Svir’ HPP to a substation in the settlement of Kolpino in the Leningradskaya Oblast’ (two Svir’ 220-kV overheads lines with a length of 247 km) over a period of 21 years (1982–2002) in total volume of 10,400 km · year are presented. Operating indicators are established with respect to specific number of disconnects and stream of failures per 100 km of overhead lines. Indicators of lightning-surge protection on the 220-kV Svir’ overhead lines passing through the same corridor primarily along a swath cut through a forest in periods when the stranded cables were protected by different schemes — stranded cable only on approaches to substations, incomplete and nonuniform protection along the route — are compared. Recommendations are given for optimal cable protection of the 220-kV Svir’ overhead lines. __________ Translated from élektricheskie Stantsii, No. 4, April 2007, pp. 49–59     

Response Matrix Minimization Used in Groundwater Management with Mathematical Programming: A Case Study in a Transboundary Aquifer in Northern Greece

Groundwater has always been considered to be a readily available source of water for domestic, agricultural and industrial use. The last decades, the lack of policymaking for the utilization of groundwater, has led to overexploitation in many areas. The cooperation of a wide range of scientists such as mathematicians, engineers, computer scientists, environmentalists and economists – operation researchers, have led to the design and construction of commercial computer programs concerned on water management and specifically on the optimal distribution of limited water resources using groundwater management models. These combined models, via simulation and optimization algorithms, result in one optimal solution through operations research and mathematical programming methods. The groundwater management models are based on the method of space superposition or the combination of space and time superposition for steady and unsteady state problems, respectively. In the present study, an algorithm is presented, which minimizes the dimension of the response matrix, concerning on two assumptions: the first is the added fixed cost which represents the water supply pumping well and the second is the removal of time superposition. The study area is a transboundary phreatic aquifer in Northern Greece, in the area of Eidomeni, a small Hellenic village just on the borderline with FYROM. The aquifer has a total area of 10,84 km², 26 operating – pumping wells, which the 9 of them consist control points of the hydraulic head. The number of the management periods is 12 months.     

Experience in the installation of a microprocessor system for controlling converter units of the Vyborg substation

The experience in the installation of modern digital systems for controlling converter units at the Vyborg converter substation on the basis of advanced microprocessor devices is considered. It is shown that debugging of a control and protection system on mathematical and physical models does not guarantee optimum control of actual converter devices. Examples of advancing the control and protection system are described, the necessity for which has become obvious in tests of actual equipment. Comparison of oscillograms of processes before optimization of the control system and after its optimization and adjustment shows that the digital control system makes it possible to improve substantially the algorithms of control and protection in the short term and without changing the hardware component. __________ Translated from élektricheskie Stantsii, No. 12, December 2005, pp. 49–54.     

Assessment of Capillary Rise from Shallow Groundwater by the Simulation Model SIMWASER Using Either Estimated Pedotransfer Functions or Measured Hydraulic Parameters

The performance of the water balance and crop growth model SIMWASER to estimate the water supply of a lawn by capillary rise from shallow ground water was investigated by using lysimeter measurements with a sandy and a clayey soil. Moreover the robustness of the model was evaluated by running it either with measured hydraulic soil parameters or with estimated pedotransfer functions (PTFs) derived from texture and bulk density. Simulations were performed for the years 1996–1998 with input data from the lysimeter station Berlin-Dahlem (Germany) for lysimeters containing undisturbed sandy or clayey soil monoliths, with groundwater at 135 cm depth. Simulated evapotranspiration and percolation/capillary rise were in good agreement with the measured data for all variants, while simulated soil water storage was acceptable only for the variants using hydraulic soil data based on laboratory measurements or using PTFs derived from known soil class and bulk density. PTFs based on mean total pore volume of the respective soil classes yielded soil water storages which were evidently too high; therefore they should be used with care and must be avoided at all in simulating the soil water balance of arid sites with shallow groundwater.     

Linking databases of different sources and scales for groundwater research in the Urema River Basin/Central Mozambique

The Urema River basin is the major sub catchment of the Pungue River basin situated in Central Mozambique. The Urema River basin controls the ecosystem of the Lake Urema, which with its extended flood plains forms a major feature of the Gorongosa National Park. The Urema River influences the flood and low water levels of the Pungue River, which is the main source of potable water of Beira – the second largest city of Mozambique. The area of the Urema river basin is densely populated and intensively used for subsistence agriculture, timber production, widely spread gold mining, tourism and nature conservation. A university project aiming at developing a model of the groundwater dynamics and assessing groundwater qualities of the Urema River basin was recently initiated. Up to now very few groundwater investigations were conducted in Mozambique. Current database management of groundwater data is poorly developed. Data are kept in tabular formats and serve mainly for record keeping purposes. Confronted with these challenges the presentation demonstrates the project's approaches of linking the various database sources to achieve a large to medium scale concept of the hydrodynamics of the Urema River basin. Based on current project findings the improvement of the resolution of digital data from current small to larger scales is necessary to enhance information contents. Further geochronological investigations are required to understand the geological evolution of the area and to update the stratigraphic order of geological formations. In future a groundwater-monitoring network needs to be established to capture long-term and baseline data.     

One Dimensional Hydrodynamic Modeling of River Flow Using DEM Extracted River Cross-sections

River cross-sections are the prime input to any river hydraulic model for simulation of water level and discharge. Field measurements of river cross-sections are labour intensive and expensive activities. Availability of measured river cross-sections is scanty in most of the developing countries, thereby making it difficult to simulate the water level and discharge using hydraulic models. A methodology for extracting river cross-sections from Shuttle Radar Topographic Mission digital elevation model (SRTM DEM) of 3-arc second has been proposed in the reported study. The extracted river cross-sections were used to simulate the magnitude of flood in the deltaic reaches of Brahmani river basin located in the eastern India. Forty cross-sections along the reaches of the rivers were extracted from the DEM and were used in the MIKE 11 hydrodynamic (MIKE 11HD) model. Prior to using the DEM-extracted river cross-sections in the model, the cross-sections were modified based on the results of the DEM error analysis. Four available measured river cross-sections were compared with the DEM-extracted modified cross-sections to examine their geometric and hydraulic similarity. By changing Manning’s roughness coefficient (n), same stage-discharge relationship could be obtained in both types of cross-sections. Subsequently, the DEM-extracted cross-sections were used in the MIKE 11HD model for the simulation of discharge and water levels at various sections of the rivers. The model was calibrated for the period of June 15–October 31 of the year 1999 and validated for the year 2003. The model validation results showed a close agreement between the simulated and observed stage hydrographs. The calibrated values of Manning’s n were found to vary within the range of 0.02 to 0.033. The study revealed that freely available SRTM DEM-extracted river cross-sections could be used in hydraulic models to simulate stage and discharge hydrographs with considerable accuracy under the scarcity of measured cross-section data.     

Geostatistically based management of arsenic contaminated ground water in shallow wells of Bangladesh

This paper investigates the effectiveness of geostatistical approaches, specifically ordinary kriging, for regional management of arsenic contaminated shallow ground water in Bangladesh. The arsenic database for reference comprised the nation-wide survey (of 3534 drinking wells) completed in 1999 by the British Geological Survey (BGS) in collaboration with the Department of Public Health Engineering (DPHE) of Bangladesh. A Monte Carlo (MC) framework was devised for selection of randomly-sampled networks of wells from this reference database. Each randomly sampled network was assumed an equi-probable exploratory field campaign designed commensurably with the requirements of rapidity and cost-effectiveness in a rural setting. In general, the kriging method was found to underestimate the arsenic concentration at non-sampled locations. This underestimation exceeded the safe limits at the Holocene region of Southcentral Bangladesh. The probability of successful prediction of safe wells for this region was found to be 72% (WHO safe limit – 10 ppb) and 78% (Bangladesh safe limit – 50 ppb). For the Pleistocene Northwestern region of Bangladesh, the safe well prediction probability was in the ranges of 90%–97%. The relatively more contaminated Holocene region in Southcentral Bangladesh, on other hand, was found more amenable to accurate geostatistical prediction of unsafe wells. Findings from this study exemplify that, while mainstream geostatistical approaches (e.g., ordinary kriging) may not provide the most accurate prediction of mean arsenic concentration at non-sampled locations, they can delineate an approximate strategy for management of arsenic contaminated shallow ground water if applied carefully. The kriging methodology is applied to a test case in Bangladesh; the approach, however, is general and is expected to have application in rural settings for other developing countries where arsenic contamination of ground water is also widespread (e.g., parts of India, Vietnam, Taiwan and Mexico).     

Sustainable Management for Minimizing Land Subsidence of an Over-Pumped Volcanic Aquifer System: Tools for Policy Design

Groundwater management scenarios for the Toluca Valley, Mexico, are examined with a three dimensional groundwater flow model coupled to a one dimensional compaction module. The objective of this study is to establish a management policy for the sustainable development and management of the Toluca aquifer system for minimizing land subsidence. Several scenarios are tested by varying 4 main parameters: recharge, exports to other basins, local consumption, and relocating pumping centers. It is apparent that continuing at current rates of water consumption will lead to subsidence of more than 1.6 m over a 40 year period (2010–2050). Completely stopping exports to Mexico City is not the most important factor in controlling subsidence because the pumping system is mostly located in regions with low clay content, where subsidence is lower. However, decreasing exports by half and relocating the pumping centres to low-clay-content areas does have a positive effect on the overall water budget and subsidence. Based on simulation results, it appears that much of the land subsidence could have been avoided had water policies been applied to restrict pumping in regions with compressible materials. The approach taken in this study could be applied to other locations with similar problems in order to determine the most viable option for water supply.