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Abstract:Prior surveys conducted have found higher proportion of arsenic-contaminated wells in villages along river Indus in Pakistan. This study aims to determine the prevalence of arsenicosis skin lesions among population exposed to higher exposure in taluka Gambat district Khairpur in Sindh. The cross-sectional survey was conducted from August 2008 to January 2009 among 610 households. A total of 707 water sources (hand pumps/wells) were tested from the villages of union councils of Agra and Jado Wahan for arsenic levels with Quick rapid arsenic field test kits. A total of 110 households exposed to arsenic levels >50 ppb were identified. Case screening for arsenic skin lesions was performed for 610 individuals residing in these 110 high-risk households. Information regarding household and socio-demographic characteristics, height and weight measurements and arsenic exposure assessment were collected. Physical examinations by trained physicians were carried out to diagnose the arsenic skin lesions. After data cleaning, 534 individuals from all age groups were included in the final analysis which had complete exposure and outcome information. Overall prevalence of arsenicosis skin lesions was 13.5 % (72 cases). Of the 534 individuals, 490 (91.8 %) were exposed to arsenic levels of 100 ppb in drinking water (8.2 % to >50-99 ppb, 58.6 % to 100-299 ppb, 14.6 % to 300-399 ppb and 18 % to 400 ppb). Prevalence rate (per 100 population) of arsenicosis was highest at arsenic levels of 100-199 ppb (15.2 cases) followed by 400 ppb (13.5 cases) and 300-399 (12.8 cases). Prevalence rate was higher among females (15.2) compared to males (11.3). Our study reports arsenicosis burden due to exposure to higher arsenic levels in drinking water in Pakistan. Exposure to very high levels of arsenic in drinking water calls for urgent action along river Indus. Prevalence of skin lesions increases with increasing arsenic levels in drinking groundwater. Provision of arsenic-free drinking water is essential to avoid current and future burden of arsenicosis in Pakistan. Keywords:Groundwater, Wells, Villages, Surveys, Drinking water
Abstract:The UNEP in its regional seas program in 1989 has included Pakistan in a group of countries which are vulnerable to the impact of rising sea level. If the present trend of sea level rise (SLR) at Karachi continues, in the next 50 years the sea level rise along the Pakistan Coast will be 50 mm (5 cm). Since the rising rates of sea level at Karachi are within the global range of 1-2 mm/year, the trends may be treated as eustatic SLR. Historical air temperature and sea surface temperature (SST) data of Karachi also show an increasing pattern and an increasing trend of about 0.67C has been registered in the air temperature over the last 35 years, whereas the mean SST in the coastal waters of Karachi has also registered an increasing trend of about 0.3C in a decade. Sindh coastal zone is more vulnerable to sea level rise than Baluchistan coast, as uplifting of the coast by about 1-2 mm/year due to subduction of Indian Ocean plate is a characteristic of Baluchistan coast. Within the Indus deltaic creek system, the area nearby Karachi is more vulnerable to coastal erosion and accretion than the other deltaic region, mainly due to human activities together with natural phenomena such as wave action, strong tidal currents, and rise in sea level. Therefore, The present article deals mainly with the study of dynamical processes such as erosion and accretion associated with sea level variations along the Karachi coast and surrounding Indus deltaic coastline. The probable beach erosion in a decade along the sandy beaches of Karachi has been estimated. The estimates show that 1.1 mm/year rise in sea level causes a horizontal beach loss of 110 mm per year. Therefore, coast eroded with rise in sea level at Karachi and surrounding sandy beaches would be 1.1 m during a period of next 10 years. The northwestern part of Indus delta, especially the Gizri and Phitti creeks and surrounding islands, are most unstable. Historical satellite images are used to analyze the complex pattern of sediment movements, the change in shape of coastline, and associated erosion and accretion patterns in Bundal and Buddo Islands. The significant changes in land erosion and accretion areas at Bundal and Buddo Islands are evident and appear prominently in the images. A very high rate of accretion of sediments in the northwestern part of Buddo Island has been noticed. In the southwest monsoon season the wave breaking direction in both these islands is such that the movement of littoral drift is towards west. Erosion is also taking place in the northeastern and southern part of Bundal Island. The erosion in the south is probably due to strong wave activities and in the northeast is due to strong tidal currents and seawater intrusion. Accretion takes place at the northwest and western parts of Bundal Island. By using the slope of Indus delta, sea encroachment and the land area inundation with rising sea level of 1 m and 2 m have also been estimated Keywords:geomorphological changes. Sea level variation, sea level rise, coastal belt, temperature
Abstract:This paper gives an overview of water resources, its availability and use, problems and constraints, the present and future challenges and the ensuing opportunities in water resource sector of one of the most populated river basins of the world; the Indus-Gangetic basin. Large-scale development of water resources in the Indus basin has led to the resource base being depleted, both in terms of quantity as well as quality. Well-developed surface irrigation systems in the Indus basin tap most of the surface water available in the basin, leaving only 10% of the net runoff to the sea, whereas from Ganges basin, the net runoff flowing to the sea is about 40%. Groundwater, which is expected to serve as buffer source to compensate for the reduced surface water availability, is also getting depleted. Energy and agricultural sector policies followed also favour large scale exploitation of groundwater resources in the basin, which has led to water table decline and a reduction in environmental flows. In the Gangetic part of the basin, it is the economic water scarcity which is more prominent. Equally important is the deterioration of water quality of Ganges river, especially when it flows along the plains accumulating municipal, industrial and domestic waste from the rapidly growing cities situated along its banks. Compounded with these issues is the role played by climate change. Since both Indus and Ganges rivers are heavily dependent on snow and glacier melts, the streamflow in these rivers is highly sensitive to climate change. Recent years have witnessed some responses to the water scarcity problem in IG basin the form of popularization of resource conservation practices, growing high yielding short duration varieties of paddy, micro and precision irrigation, regulations to control groundwater use and management. The article presses the need for water resources in the basin to be managed in a conjunctive manner, considering rain water, surface water, soil water and groundwater in continuum. Considering the inter-linkage between groundwater extraction, energy and food policies, groundwater management strategies should have a focus on energy pricing, food pricing and procurement policies also. Nevertheless, devising long-term strategies on water resource management in the basin need not overlook the likely impacts that the changing climate is going to have on water resources. Keywords:Groundwater recharge, Arsenic, Water scarcity, Water pollution, Flooding, Climate change, River basins, Hydrogeology, Analysis, Precipitation, Evaporation, Runoff, Water quality, Water table, Water governance, Groundwater management, Tube wells, Irrigation programs , Water quality
Abstract:Glaciers are among the best indicators of terrestrial climate variability, contribute importantly to water resources in many mountainous regions and are a major contributor to global sea level rise. In the Hindu Kush-Karakoram-Himalaya region (HKKH), a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance. There is, however, indirect evidence of a complex pattern of glacial responses in reaction to heterogeneous climate change signals. Here we use satellite laser altimetry and a global elevation model to show widespread glacier wastage in the eastern, central and south-western parts of the HKKH during 2003-08. Maximal regional thinning rates were 0.660.09 metres per year in the Jammu-Kashmir region. Conversely, in the Karakoram, glaciers thinned only slightly by a few centimetres per year. Contrary to expectations, regionally averaged thinning rates under debris-mantled ice were similar to those of clean ice despite insulation by debris covers. The 2003-08 specific mass balance for our entire HKKH study region was -0.210.05 m yr-1 water equivalent, significantly less negative than the estimated global average for glaciers and ice caps. This difference is mainly an effect of the balanced glacier mass budget in the Karakoram. The HKKH sea level contribution amounts to one per cent of the present-day sea level rise. Our 2003-08 mass budget of -12.83.5 gigatonnes (Gt) per year is more negative than recent satellite-gravimetry-based estimates of -53 Gt yr-1 over 2003-10 (ref. 12). For the mountain catchments of the Indus and Ganges basins, the glacier imbalance contributed about 3.5% and about 2.0%, respectively, to the annual average river discharge, and up to 10% for the Upper Indus basin. Keywords:Glaciers, Climate change, Water resources, Satellite observation, River basins
Abstract: Keywords:Rivers, Watersheds, Irrigation, Climate change, Dams, C68 Computable General Equilibrium Models, Computable General Equilibrium (CGE) model, Computable General Equilibrium water model
Abstract:Over-exploitation of groundwater resources threatens the future of irrigated agriculture, especially in the arid and semi-arid regions of the world. In order to reverse this trend, and to ensure future food security, the achievement of sustainable groundwater use is ranking high on the agenda of water policy makers. Spatio-temporally distributed information on net groundwater use--i.e. the difference between tubewell withdrawals for irrigation and net recharge--is often unknown at the river basin scale. Conventionally, groundwater use is estimated from tubewell inventories or phreatic surface fluctuations. There are shortcomings related to the application of these approaches. An alternative methodology for computing the various water balance components of the unsaturated zone by using geo-information techniques is provided in this paper. With this approach, groundwater recharge will not be quantified explicitly, but is part of net groundwater use, and the spatial variation can be quantitatively described. Records of routine climatic data, canal discharges at major offtakes, phreatic surface depth fluctuations, and simplified information on soil textural properties are required as input data into this new Geographic Information System and Remote Sensing tool. The Rechna Doab region (approximately 2.97 millionha), located in the Indus basin irrigation system of Pakistan, has been used as a case study. On an annual basis, an areal average net groundwater use of 82mmyear super(-1) was estimated. The current result deviates 65% from the specific yield method. The deviation from estimates using tubewell withdrawal related data is even higher.Original Abstract: La surexploitation des ressources en eau souterraine menace le futur de l'agriculture irrigue, specialement dans les zones arides et semi-arides du monde. De maniere a renverser la tendance, et d'assurer la securite alimentaire, l'utilisation durable des eaux souterraines est devenue une priorite dans l'agenda des politiques de l'eau. La distribution spatio-temporelle de l'usage net de l'eau souterraine (la difference entre l Keywords:Climatic data , Spatial variations , Water balance , Soils , Irrigation , Ground water , Remote sensing , River basins , Water policy , Selective Withdrawal , Remote Sensing , Climatic Data , Groundwater Mining , Hydrologic Budget , Basin Irrigation , Groundwater , Fluctuations , Geographical Information Systems , Selective Withdrawal , Remote Sensing , Climatic Data , Groundwater Mining , Hydrologic Budget , Basin Irrigation , Groundwater , Fluctuations , Geographical Information Systems , Pakistan , Freshwater
Abstract:Pakistan is an agricultural country. The supply of irrigation water to crops is being made through a network of surface irrigation systems and groundwater. The left Bank of Lower Indus covers administrative boundaries of ten districts which includes districts of Nawabshah and Sanghar. The government of Sindh Province installed more than 350 scavenger (saline and fresh bores together) tubewells in Districts Nawabshah and Sanghar with the main objective of providing drainage and to recover shallow fresh groundwater for irrigation supplements. The study was carried out in a command area of 79 tube wells of District Nawabshah to examine the effect of these tube wells on sustainable rural livelihood of irrigated agriculture community. The continuous pumping from the scavenger tube wells for more than two days indicated that there was not any significant change in water quality, thus it is concluded that the scavenger tube well is a good method to control saltwater movement in to freshwater zone by balancing or keeping interface at constant level provided that the ratio of saline water to freshwater pumping is 1:1. Pre-project findings reveal that 91 % of irrigated agricultural land had a severe water logging situation and 9% of the area was moderately water logged. The recorded average water table depth was <0.15 m. The cropping intensity was recorded at <30% and the maximum yield of major crops such as cotton, wheat and rice was 1080, 1400 and 1400 kg/acre and the maximum land value was less than Rs. 40000 per acre. The women and children were the most affected because more than 85% of rural women were engaged in agricultural activities. Post project (1999-2007) results indicated that the average water table depth was below 1.5 m depth from the surface. However, the categorical decrease in water table was: 60% area was below 1.75 m depth and 40% area was between 0.75 and 1.5 m depth. The maximum crop yield of major crops such as cotton, wheat and rice was increased to 148%, 55% and 55%, respectively, and the cropping intensity was increased to 149%. The land value of agriculture command area was also increased to more than Rs. 150 000 per acre (274%). Operation and maintenance of tube wells was determined as Rs. 315/acre, which includes charges of electricity, person deployed for operation, maintenance of tube well and disposal channels. Presently, all this cost is borne by the government of Sindh. The influence of reverse seepage of saline water from the disposal channels has been investigated, which indicated that when channels were constructed above ground surface level, then the seepage of saline water affected about 30 m width in each side of the channel area (Kori et al., 2009). It is concluded that the scavenger tube well was a good approach to control water logging, protect salt water intrusion into the freshwater zone, increase cropping intensity and sustain rural livelihood of irrigated agriculture community. Further, if the operation and maintenance is given to the farmer community then it would be unacceptable to the farmer community because its operation and maintenance is beyond the scope of farmer due to cost and technicality. Also, the scavenger tube wells maintain an unchangeable saline-freshwater interface. Keywords:scavenger tube wells, Drainage, rural livelihoods, aquifer, groundwater, Sindh, Pakistan, irrigation