A new technique to estimate net groundwater use across large irrigated areas by combining remote sensing and water balance approaches, Rechna Doab, Pakistan

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 million ha), 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 82 mm year^–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.

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Resumen La sobre-explotación de recursos de agua subterránea amenaza el futuro de la agricultura de riego, especialmente en las regiones áridas y semi-áridas del mundo. Para revertir esta tendencia, y para garantizar seguridad alimentaria futura, la meta del uso sostenible del agua subterránea se encuentra alto en la agenda de los políticos. Información espacial y temporal en cuanto al uso neto de agua subterránea- i.e. la diferencia entre las extracciones de agua de pozos entubados para riego y recarga neta- se desconoce frecuentemente a la escala de cuenca hidrográfica. Generalmente, el uso de agua subterránea se estima a partir de inventarios de pozos o fluctuaciones de superficies freáticas. Existen deficiencias en relación con las aplicaciones de estos enfoques. En este artículo se aporta una metodología alternativa para calcular los diferentes componentes del balance hídrico de la zona no saturada utilizando técnicas geoinformativas. Aunque con este enfoque no se cuantifica de manera explícita la recarga de agua subterránea, la cual es parte del uso neto de agua subterránea, puede describirse cuantitativamente la variación espacial. Para esta nueva herramienta de Sistemas de Información Geográfica y Sensores Remotos se requieren datos de entrada como registros rutinarios de datos climáticos, descargas de canales en salidas principales, fluctuaciones de profundidades de superficies freáticas, e información simplificada de las propiedades texturales de los suelos. Se ha utilizado como estudio de caso la región Rechna Doab (aproximadamente 2.97 millones ha), localizada en el sistema de riego de la cuenca Indus de Pakistán. Se ha estimado un uso promedio areal anual de agua subterránea de 82 mm año^–1. El resultado obtenido difiere en un 65% del método de productividad específica. La diferencia en relación a estimados provenientes de extracciones en pozos entubados es aún mucho más alta.

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Résumé La surexploitation des ressources en eau souterraine menace le futur de lagriculture irrigué, spécialement dans les zones arides et semi-arides du monde. De manière à renverser la tendance, et dassurer la sécurité alimentaire, lutilisation durable des eaux souterraines est devenue une priorité dans lagenda des politiques de leau. La distribution spatio-temporelle de lusage net de leau souterraine (la différence entre l ‹eau pompée et la recharge nette) est rarement connue à léchelle dun bassin versant. Conventionnellement, lutilisation des eaux souterraines est estimée à partir des données de rabattement ou les données de fluctuation du niveau de la nappe phréatique. Il y a des défauts dans ces approches. Une méthodologie alternative pour calculer les différents composants de la balance hydrologique est présentée dans cet article. Avec cette approche, la recharge des eaux souterraines ne sera pas quantifiée de manière explicite, mais sera considérée comme une part de lutilisation nette en eau souterraine, et la variation spatiale peut être décrite quantitativement. Les chroniques des données climatiques, les débits du réseau hydrographique majeur, les fluctuations de la surface de la nappe phréatique, et des données basiques sur la texture du sol sont nécessaires et sont rentrées dans un nouveau Système dInformation Géographique et outil de télédétection. La région de Rechna Doab au Pakistan, environ 2.97 millions dhectare, localisée dans le bassin irrigué de lIndus, a été utilisé comme cas détude. Sur base annuelle, lutilisation nette de leau souterraine est estimée à 82 mm. en moyenne. Le résultat obtenu diffère de 65% du résultat de la méthode du débit spécifique. La différence avec le résultat obtenu en observant le rabattement des puits est encore plus élevée.

     

Sustainable groundwater extraction in coastal areas: a Belgian example

Water extractions in coastal areas have to deal with salt water intrusion and lowering of hydraulic heads in valuable ecosystems. Therefore, sustainable management of fresh water resources in these areas is crucial. This is illustrated here with two water extractions in the western Belgian coastal plain which extract groundwater from a phreatic dune aquifer. One water extraction faced problems with salt water intrusion, while lowering of hydraulic heads was an issue for both. To remedy the salt water intrusion, it was found that decreasing the extraction rate was the only solution. To offset this and to increase hydraulic heads around both extractions, it was decided to artificially recharge the aquifer of the second extraction with tertiary treated wastewater. By taking these interventions, the combined production capacity of the water extractions was increased with 56% whereas 27% less water was extracted from the dune aquifer itself. Extraction history and the effects of interventions are illustrated for both water extractions with water quality data and fresh water head observations. A more detailed insight in groundwater flow and fresh–salt water distribution in the aquifer is provided by simulating the evolution of the water extractions with a 3D density dependent groundwater flow model.     

Multiple approaches to formation processes: The Pine Spring Site,southwest Wyoming

Excavations in 1964 at the Pine Spring site in southwest Wyoming concluded that the site contains three cultural occupation levels; the earliest allegedly dates to the terminal Pleistocene and is associated with megafauna. However, excavations in 1998 and 2000, and analysis of the stratigraphy, AMS dates, micromorphology, and artifact carbonate isotopes, along with debitage refitting, density, orientation, inclination, burning, and trample damage, could not replicate the 1964 findings. A hiatus in deposition accounts for the highest density of artifacts, and the three original occupations are palimpsests. There is no unequivocal association between evidence of human activity and megafaunal remains. © 2006 Wiley Periodicals, Inc.     

Mercury emission from the indigenous mercury smelting in Wuchuan mercury mining areas, Guizhou Province, China

Mercury smelting is one of the important anthropogenic atmospheric mercury emission sources. Small-scale mercury smelting activities with indigenous method which is considered illegal and forbidden by local government always extensively existed in the Wuchuan area, northeastern Guizhou Province, China. Because of the simple processes without any environmental protection, a large amount of mercury vapor released to the ambient air during the processing of cinnabar roasting. By determining mercury concentrations in mercury ore and smelting slag samples, a mass balance method was used to calculate mercury emission factors and annual mercury emission from indigenous mercury smelting in Wuchuan mercury mining areas, Guizhou Province, China. The mercury emission factors ranged from 6.9% to 32.1% with the recovery from 78.4% to 93.6% and the annual mercury emission was up to 3.7-9.6 metric tons. The results highlighted that the indigenous mercury smelting was one of the most important anthropogenic atmospheric mercury emission sources in this region.     

Protected areas in Saudi Arabia: Sustainable use of natural resources

The present paper reviews the conservation movement in Saudi Arabia as measured against the established protected areas, as well as the basic philosophy regarding natural resource management. The degree of representation of the biophysical diversity of Saudi Arabia in the established protected areas is discussed by using three areas as case studies: Harrat Al-Harrah (lava field), Urug Bani Mu'arid (Cuesta and Sand), and Raydah Escarpment (High Mountain).     

The relationship between indigenous pastoralist resource tenure and state tenure in Somalia

Indigenous resource tenure systems in Africa have evolved to meet the constraints and opportunities of often difficult biophysical environments, while facilitating the operation of complex spatial and temporal land use patterns. Traditional systems provide security of tenure in culturally relevant ways that permit adaptation to new circumstances. On the other hand imposed tenure structures in Africa have often not strengthened individual rights and have often blocked indigenous tenure development and adaption in response to new situations.Pastoralists in Africa have in particular been negatively impacted by the imposition of national tenure systems which in many cases have served to marginalize nomadic populations, with repercussions in land degradation, food security, and instability.In Somalia the transient resource rights and resource use arrangements that are critical to transhumant pastoralism were ignored in the formulation of the national tenure regime which favored crop cultivation. The results were increased land degradation, resource use conflicts, declines in pastoral production, and impacts on Somali clan alliances which in many cases regulate rational resource access and use.Somalia possesses the greatest proportion of pastoralists in Africa. Transhumant pastoralism, as the most widespread agricultural enterprise in the country, will play a critical role in food production for the foreseeable future. However, the relationship between indigenous pastoralist tenure and state imposed tenure has, in many locations decreased the ability of pastoralism to reproduce itself, thereby compromising the rational utilization of very large areas of rangeland interior, which have very few alternative uses.     

我国矿区棕地综合治理及再利用

矿区土地治理与再利用是一项紧迫的任务,由于多年的矿产开采,导致矿区的大面积土地破坏和废弃,土壤及地下水污染,从而形成了矿区棕地并造成大量的土地价值损失,加剧了矿区的人地矛盾。因此,研究棕地这一类特殊土地的再利用对于矿区的可持续发展具有重要的现实意义。通过分析国内外矿区棕地研究相关理论与方法,结合我国矿区棕地的现状,探讨了矿区棕地综合治理的方案和措施。建议我国矿区棕地治理和再利用方案框架可划分为调查评价、生态修复和土地复垦与景观再造3个阶段：调查评价阶段主要包括棕地土壤环境质量评价与可持续利用评价;生态修复阶段可选择适宜的技术方法进行污染土壤和地下水修复;土地复垦与景观再造阶段是根据矿区棕地类型及分布特点,因地制宜,进行棕地复垦和综合治理利用。同时讨论了每个阶段的主要工作内容和措施,比较了不同修复技术方法的优劣,给出了我国矿区棕地复垦和综合利用的模式建议。     

Characterizing flood hazard risk in data-scarce areas,using a remote sensing and GIS-based flood hazard index

The frequency in occurrence and severity of floods has increased globally. However, many regions around the globe, especially in developing countries, lack the necessary field monitoring data to characterize flood hazard risk. This paper puts forward methodology for developing flood hazard maps that define flood hazard risk, using a remote sensing and GIS-based flood hazard index (FHI), for the Nyamwamba watershed in western Uganda. The FHI was compiled using analytical hierarchy process and considered slope, flow accumulation, drainage network density, distance from drainage channel, geology, land use/cover and rainfall intensity as the flood causative factors. These factors were derived from Landsat, SRTM and PERSIANN remote sensing data products, except for geology that requires field data. The resultant composite FHI yielded a flood hazard map pointing out that over 11 and 18% of the study area was very highly and highly susceptible to flooding, respectively, while the remaining area ranged from medium to very low risk. The resulting flood hazard map was further verified using inundation area of a historical flood event in the study area. The proposed methodology was effective in producing a flood hazard map at the watershed local scale, in a data-scarce region, useful in devising flood mitigation measures.     

Exposure of smelting workers to mercury vapor with indigenous method for mercury smelting in Wuchuan areas, Guizhou Province, China

Small-scale mercury smelting activities with indigenous method are always extensive in the Wuchuan area, northeastern Guizhou Province, China. Because of the simple processes without any environmental protection, a large amount of mercury vapor released to the ambient air during the processing of cinnabar roasting. So the health of the workers may be negatively affected through inhalation of the mercury-polluted air. Mercury, creatinine and β2-MG contents in urine among the workers in the study areas and the residents in the control site （Changshun County） were determined to discuss the health impact of mercury vapor exposure to the workers in the study areas. Health examinations also were carded out to identify clinical symptoms of mercury poisoning for the smelting workers. Results indicated that the geometric mean value of urinary mercury for the smelting workers was g/g Cr μg/g Cr （N=22）, significantly higher than 1.24 μg/g （N=54） for residents in the control site. β2-MG as a renal biomarker can be used to study human nephrotoxicity at an early stage and it is most useful to define effects for assessing re-absorption function to indicate tubular injury. The results showed a serious adverse effect on renal system for the smelting workers due to mercury exposure. Several workers have already manifested some clinical symptoms of lightly chronic mercury poisoning and the symptoms include finger and eyelid lightly tremor, gingivitis and blue mercury line in mouth. The study illuminated that the workers in gaged in indigenous mercury smelting in the Wuchuan area were seriously exposed to mercury vapor,     

岩溶区河流水化学昼夜变化与生物地球化学过程

河流水化学昼夜动态变化的研究有助于揭示水体中相对快速的生物地球化学过程(河流内过程),同时也有助于判别上游补给区流域过程。已有的研究表明生物过程(光合作用与呼吸作用)、地球化学过程(碳酸盐平衡、碳酸钙沉积)是控制河流 pH、SpC、Ca2+和 HCO -3含量昼夜变化的主要因素。不同级别、类型及河床微环境均会对水化学昼夜变化产生影响,与气温密切相关的光合作用是产生河水 pH 值和 DO 昼夜变化的主控因素。在偏碱性与富含钙离子的岩溶河流,有机体的钙化作用与酸分泌可能对光合作用具有重要作用,从而导致水体中 Ca2+和 HCO -3出现白天下降-夜间回升的昼夜动态变化,下降幅度达20%~30%。水生植物通过光合作用产生 DIC(主要为 HCO -3)的原位沉降,是真正意义上的净碳汇。昼夜生物地球化学循环及效应研究有助于全面认识岩溶区碳循环特征及岩溶含水层源汇关系,尤其是岩溶碳汇稳定性与净碳汇估算;同时对长时间尺度河流监测计划的制定具有重要意义。     

Walking the line: Participatory mapping, indigenous rights, and neoliberalism

Recent critiques of participatory mapping point out the degree to which, as a practice, it has become disciplined by legal prospects for recognition often adopted as part of neoliberal reforms. Yet while neoliberalism certainly disciplines the practice of mapping, they are not reducible to expressions of its dominance. Through a discussion of a participatory mapping project in the Mosquitia region of Honduras, I show how the practice of producing and using maps involves negotiating a spatially complex terrain shaped by multiple and overlapping forms of territory and authority. Insofar as mapping involves movement through this terrain, it engages multiple spatialities that inform assessments of the potential for legal recognition and critically awareness of its constraints. Questions of what to map and how to go about doing it are thus never merely technical concerns. Instead they are diagnostic of broader relations of power that position participants in mapping projects. Rather than producing an authoritative account of that process, my argument here is aimed at learning from it, developing the prospects for a critically-informed, collaborative approach to mapping.     

Parents,permission, and possibility: Young women,college, and imagined futures in Gujarat,India

This article advances critical geographies of youth through examining the spatiality implicit in the imagined futures of young women in rural India. Geographers and other scholars of youth have begun to pay more attention to the interplay between young people’s past, present, and imagined futures. Within this emerging body of scholarship the role of the family and peer group in influencing young people’s orientations toward the future remain underexamined. Drawing on eleven months of ethnographic fieldwork, my research focuses on a first generation of college-going young women from socioeconomically marginalized backgrounds in India’s westernmost state of Gujarat. I draw on the “possible selves” theoretical construct in order to deploy a flexible conceptual framework that links imagined post-educational trajectories with motivation to act in the present. In tracing the physical movement of these young women as they navigate and complete college, my analysis highlights the ways in which particular kinds of spaces and spatial arrangements facilitate and limit intra- and inter-generational contact, and the extent to which this affects young women’s conceptions of the future. I conclude by considering the wider implications of my research for ongoing debates surrounding youth transitions, relational geographies of age, and education in the Global South.     

Spatial relationships between natural seismicity and faults, southeastern Ontario and north-central New York state

A statistical analysis was carried out to investigate spatial associations between natural seismicity and faults in southeastern Ontario and north-central New York State (between 73°18′ and 77°00′W and 43°30′ and 45°18′N). The study area is situated to the west of the seismically active St. Lawrence fault zone, and to the east of the Lake Ontario basin where recently documented geological and geophysical evidence points to possible neotectonic faulting. The weights of evidence method was used to judge the spatial associations between seismic events and populations of faults in eight arbitrarily defined orientation groups. Spatial analysis of data sets for seismic events in the periods 1930–1970 and post-1970 suggest stronger spatial associations between earthquake epicentres and faults with strikes that lie in the NW–SE quadrants, and weaker spatial associations of epicentres with faults that have strikes in the NE–SW quadrants. The strongest spatial associations were determined for groups of faults with strikes between 101° and 146°. The results suggest that faults striking broadly NW–SE, at high angles to the regional maximum horizontal compressive stress, are statistically more likely to be spatially associated with seismic events than faults striking broadly NE–SW. If the positive spatial associations can be interpreted as indicating genetic relationships between earthquakes and mapped faults, then the results may suggest that, as a population, NW–SE trending faults are more likely to be seismically active than NE–SW striking faults. Detailed geological studies of faults in the study area would be required to determine possible neotectonic displacements and the kinematics of the displacements.     

Site formation processes in loess areas: A case study from moravany-žakovska,western slovakia

The site of Moravany-Žakovska in western Slovakia is situated in a loessic terrain and is dated to the end of the Late Glacial Maximum. This article shows the importance of analyzing the 0.01-0.1 mm fraction to interpret the sedimentological environment and a number of measured anthropogenic indices, such as burnt quartz grains, charcoal, radiolarite chips, microflakes, and microfragments of bone. Analysis of the profile of the site through time reveals the relationship between occupational levels and phases of slope wash that occurred during wetter climatic episodes; these are separated by phases of aeolian sedimentation. At the same time, analysis of anthropogenic indices in this size fraction permitted the identification of occupational levels, including those not recorded by macrofinds. Analysis of anthropogenic indices in horizontal exposures enabled the identification of latent settlement structures such as hearths, areas of radiolarite processing, zones where mineral dyes were prepared, and other structures not recorded by macrofinds.     

Helophyte zonation in two regulated estuarine areas in the Netherlands: Vegetation analysis and relationships with hydrological factors

The relationship between hydrological conditions and riparian helophyte vegetation was studied in two freshwater estuaries that differed in tidal regulation in order to assess the effects of large-scale hydrological regulation on the fringe vegetation. Vegetation and environmental variables were sampled for 206 sites in the Rhine-Meuse estuary (146 sites) and the IJsselmeer region (60 sites) in the Netherlands. These samples were classified into 10 vegetation types, all of which were dominated by tall helophytes. The most common vegetation types were dominated byPhragmites australis andTypha angustifolia, which formed both monospecific stands and mixtures. Tall Cyperaceae dominated three vegetation types (dominated individually bySchoenoplectus lacustris, Bolboschoenus maritimus, andSchoenoplectus tabernaemontani).Acorus calamus. Principal components analysis of the species composition of vegetation fringing open-water areas and associated environmental data revealed complex gradients incorporating differences in water depth, water-level fluctuation, were exposure, and sedimentation and/or erosion. The composition of the helophyte belts varied among the areas as the result of the differing times at which regulation occurred. Based on historical data, hydrological regulation of the estuaries has resulted in deterioration of intertidalSchoenoplectus andBolboschoenus stands, due to erosion and predation.P. australis stands have been invaded by terrestrial plant species or have been replaced byT. angustifolia. A scheme is presented of helophyte vegetation development under the influence of changes in the hydrological regime.     

Indigenous attitudes,ecotourism, and Mennonites: Recent examples in rainforest destruction/preservation

During the Summer of 1992, the author traveled to three distinctive rainforest regions. Two were located in Ecuador: the west coastal rainforest and the northern Oriente, a headwater region of the Amazon Basin. The third rainforest was located in the northwestern region of Belize. As a member of a study group sponsored by Save the Rainforest, Incorporated, the author was involved with the Programme for Belize Research station at Rio Bravo. Having witnessed a variety of types of rainforest destruction in the Brazilian Amazon during the summer of 1989 and the accompaying multitude of indigenous attitudes concerning the same, the author was keenly aware of destruction/preservation activities in these other regions.The indigenous peoples encountered during these travels displayed conservation-minded attitudes and a true desire to save the rainforest. In addition, three ecotourism resorts were encountered during these visits. Though these profit-making establishments do not contribute financial support to local conservation efforts, they do represent large investment concerned with rainforest protection. In Belize the immigration of Mennonites has been considerable. Though their American counterparts may observe a quaint and simplistic lifestyle, in Belize, Mennonites are a major destructive force.     

Assessment of hazardous mine waste transport in west central Sinai,using remote sensing and GIS approaches: a case study of Um Bogma area,Egypt

Um Bogma area is the most famous mineralized locality in Sinai, Egypt. It is characterized by the presence of manganese, iron, and copper deposits. Apart from the mill tailings and spoil heaps, the results indicated the decrease of soil contamination downstream. As a result of random manganese mining activity in Um Bogma area, many hazardous elements such as iron, copper, manganese, lead, and zinc as well as many others associating heavy metals such as arsenic, selenium, and sulfur are dispersed in the environment. This study assesses and monitors the environmental impacts of such mining activities in the west central Sinai, using multitemporal spectral remote-sensing sensors (MSS 1972, TM 1986, and ETM+7 2000). The results have shown the very high potential of temporal imagery in mining-related contamination either directly through mineral and rock mapping of the mining waste and residues and related contaminated areas.     

Late-Pleistocene and mid-Holocene environmental changes in highland valley head areas of Santa Catarina state, Southern Brazil

Low resolution of the continental sedimentary record is a common source of skepticism about the application of geomorphology and sedimentology to Quaternary studies. In spite of this, when supported by independent proxy data, geomorphology and sedimentology may favor palaeo-hydrologic interpretation. This paper associates geomorphologic, stratigraphic, sedimentologic, isotopic, palynologic and geochronologic data. The research was conducted in valley head sites in southern Brazilian highlands, under mild subtropical climate. The results point to environmental changes, the ages of which coincide to Marine Isotopic Stages (MIS) 5b, 3, 2 and 1. Although late-Pleistocene temperatures and precipitation were lower than those of today, the study valley heads seem to have sustained locally wetter environments, which fed shallow soil–water saturated zones. These saturated zones are believed to have expanded during transitions between stadial and interstadial states, contributing to hillslope erosion and sedimentation regardless of the sign of the climatic change. The interior organization of holocenic slope-wash deposits suggests that the mid-Holocene climate was drier than today’s and was under the influence of seasonally contrasting precipitation regimes. The predominance of overland flow-related sedimentary records suggests that an excess of precipitation over evaporation influenced local palaeo-hydrology. This palaeo-hydrologic condition seems to have been recurrent and also explains the alternating periods of pedogenesis and sedimentation.