Groundwater demand management at local scale in rural areas of India: a strategy to ensure water well sustainability based on aquifer diffusivity and community participation

Watershed development programmes provide an opportunity for sustainable management strategies, although currently, they remain largely supply-side mechanisms of water resources development. Hydrogeological conditions, community participation and status of groundwater usage are important in evolving strategies on demand-side groundwater management.Neemkheda aquifer is a typical low-storage, low-hydraulic conductivity aquifer from a watershed in the dryland regions of Madhya Pradesh State of central India. A shallow unconfined aquifer, it consists of an upper coarse, calcareous sandstone unit underlain by a fine-grained sandstone unit. A well commune of seven wells is poised to test the concept of joint groundwater management, wherein wells are mechanisms of tapping a common water source, the Neemkheda aquifer.The strategy for systematic groundwater management in the Neemkheda well commune is based upon the relationship between Transmissivity (T) and Storage coefficient (S), i.e. aquifer diffusivity, and its variation within the aquifer. Wells within a high diffusivity domain tend to dewater more quickly than wells within a low diffusivity domain. A well-use schedule during the dry season, based upon aquifer diffusivity forms the basis of the groundwater management concept. The distribution of local aquifer diffusivities governs the relationship between local and regional aquifer depletion times and forms the basis of the groundwater management exercise being proposed for the Neemkheda aquifer.

---

Resumen Los programas de desarrollo de una cuenca hídrica son una oportunidad para el uso de estrategias de gestión sostenible, aunque hoy en día estas siguen siendo principalmente mecanismos para el desarrollo de recursos hídricos con énfasis en la oferta. Las condiciones hidrogeológicas, la participación comunitaria y la condición de utilización del agua subterránea, son importantes en el desarrollo de estrategias para la gestión del agua subterránea, desde el punto de vista de la demanda.El acuífero de Neemkheda es un acuífero típico de almacenamiento bajo y conductividad hidráulica baja, perteneciente a una cuenca hídrica ubicada en las regiones secas del Estado de Madhya Pradesh, en la parte central de India. Un acuífero de tipo libre, somero, formado por una unidad superior de arenisca calcárea de grano grueso, subyacida por una unidad de arenisca de grano fino.Un campo de pozos comunitario compuesto por siete pozos, pone a prueba el concepto de gestión conjunta del agua subterránea, dentro del cual los pozos son mecanismos para usar una fuente de agua común: El acuífero de Neemkheda.La estrategia usada para la gestión sistemática del agua subterránea, en el campo de pozos comunitario de Neemkheda, se basa en la relación existente entre Transmisividad (T) y Coeficiente de Almacenamiento (S), es decir en la Difusividad del Acuífero y en su variación observada dentro del mismo acuífero. Los pozos cuya difusividad esta dentro de un rango alto, tienden a experimentar un descenso en su nivel mas rápidamente que aquellos pozos con una difusividad baja. El concepto de gestión de agua subterránea se basa en un programa especial de operación para cada pozo durante la estación seca, el cual a su vez se basa en la difusividad del acuífero. La distribución de difusividades locales del acuífero rige las relaciones entre las épocas de descensos de nivel en el acuífero a escala regional y local, y además constituyen la base del ejercicio de la gestión del agua subterránea que se esta proponiendo para el acuífero de Neemkheda.

---

Résumé Les programmes de développement des bassins versants offrent une occasion de développer des stratégies pour une gestion durable, bien qu à présent elles restent en grande mesure le terme source dans le mécanisme de développement de la ressource en eau. Les conditions hydrogéologiques, la participation de la communauté et lusage des eaux souterraines sont importants pour le terme demande dans les stratégies de gestion des eaux souterraines. Laquifère de Neemkheda presents des caractéristiques typiques pour un bassin versant dans les régions arides de létat Madhya Pradesh de lInde centrale en ce qui concerne les faible valeurs de la conductivité hydraulique et du coéfficient demmagasinement. Il sagit dun aquifère phrèatique dont la partie supérieure est constitué par des grès calcaire qui restent sur des grés plus fins. Afin dessayer le concept de gestion integrée, on a réalisé dans laquifère de Neemkheda un captage ayant sept forages qui forment la ressource en eau communale. La stratégie de la gestion systématique du captage est basée sur la relation entre la transmissivité (T), le coéfficient demmagasinement (S), donc la diffusivité hydraulique ainsi que sa variation spatiale. Les puits forés dans les zones à grande diffusivité tendent à sassècher plus vite que ceux creusés dans des zones à faible diffusivité. Le concept de la gestion des eaux souterraines est donc basé sur la distribution spatiale des diffusivités. À partir de ce concept on a développé un programme dexploitation des forages pendant les saisons sèches. La relation entre les temps d épuissment locaux et régionaux est determiné par la distribution spatiale de la diffusivitée et forme la base de lexercice sur la gestion des eaux proposée pour laquifère de Neemkheda.

     

GCP collection for corona satellite photographs: Issues and methodology

Use of high-resolution and historic CORONA satellite photographs for mapping and other purposes requires Ground Control Points (GCPs), as ephemeris data and image parameters are not available. However, the alterations in landscape in last 34 years (i.e., since the acquisition of these photographs) prevent identification and collection of large number of GCPs in the field. This paper presents a methodology for collection of GCPs for CORONA photographs. The advantages and limitations of the methodology are discussed. For a study site, situated in Siwaliks and Lower Himalayas, the GCPs were identified in CORONA photographs and their WGS84 coordinates were estimated through a process of datum transformation and georeferencing. Estimated GCP coordinates from the topo sheets and 2D and 3D views of photographs, helped in identifying the GCP locations in field, which were observed using DGPS. Investigations were carried out to relate Differential Global Positioning System (DGPS) accuracy with base line length and time of observation. Abase line of 350 km and half an hour observation were found appropriate to yield accuracy in GCP collection by DGPS method, which conforms to CORONA resolution of 3 m.     

Rotational Modulation of Microwave Solar Flux

Time series data of 10.7 cm solar flux for one solar cycle (1985–1995 years) was processed through autocorrelation. Rotation modulation with varying persistence and period was quite evident. The persistence of modulation seems to have no relation with sunspot numbers. The persistence of modulation is more noticeable during 1985–1986, 1989–1990, and 1990–1991. In other years the modulation is seen, but its persistence is less. The sidereal rotation period varies from 24.07 days to 26.44 days with no systematic relation with sunspot numbers. The results indicate that the solar corona rotates slightly faster than photospheric features. The solar flux was split into two parts, i.e., background emission which remains unaffected by solar rotation and the localized emission which produces the observed rotational modulation. Both these parts show a direct relation with the sunspot numbers. The magnitude of localized emission almost diminishes during the period of low sunspot number, whereas background emission remains at a 33% level even when almost no sunspots may be present. The localized regions appear to shift on the solar surface in heliolongitudes.     

十字石的原位高压X射线衍射研究

利用原位高压同步辐射能量色散X射线衍射技术,在室温下对采自新疆阿尔泰地区冲乎尔递增变质带的天然十字石进行高压晶体结构测定,测量的压力范围为0.0001~3.9GPa,共11组有效数据。实验表明,在实验压力范围内,随着压力的增加晶胞参数β值逐渐增大,表明了十字石的结构对称性随压力增加而有所降低;同时,在1.5~2.7GPa压力范围内,十字石的晶体结构也发生了改变。     

On the Performance Evaluation of Pan-Sharpening Techniques

The limitations of the currently existing pan-sharpening quality indices are analyzed: the absolute difference between pixel values, mean shifting, and dynamic range change is frequently used as spatial fidelity measurement, but they may not correlate well with the actual change of image content; and spectral angle is a widely used metric for spectral fidelity, but the spectral angle remains the same if two vectors are multiplied by two individual constants, which means the average spectral angle between two multispectal images is zero even if pixel vectors are multiplied by different constants. Therefore, it is important to evaluate the quality of a pan-sharpened image under a task of its practical use and to assess spectral fidelity in the context of an image. In this letter, three data analysis techniques in linear unmixing, detection, and classification are applied to evaluate spectral information within a spatial scene context. It is demonstrated that those old but simplest approaches, i.e., Brovey and multiplicative (or after straightforward adjustment) methods, can generally yield acceptable data analysis results. Thus, it is necessary to consider the tradeoff between computational complexity, actual improvement on application, and hardware implementation when developing a pan-sharpening method.     

Efficiency of carrier-phase integer ambiguity resolution for precise GPS positioning in noisy environments

Precise GPS positioning relies on tracking the carrier-phase. The fractional part of carrier-phase can be measured directly using a standard phase-locked loop, but the integer part is ambiguous and the ambiguity must be resolved based on sequential carrier-phase measurements to ensure the required positioning precision. In the presence of large phase-measurement noise, as can be expected in a jamming environment for example, the amount of data required to resolve the integer ambiguity can be large, which requires a long time for any generic integer parameter estimation algorithm to converge. A key question of interest in significant applications of GPS where fast and accurate positioning is desired is then how the convergence time depends on the noise amplitude. Here we address this question by investigating integer least-sqaures estimation algorithms. Our theoretical derivation and numerical experiments indicate that the convergence time increases linearly with the noise variance, suggesting a less stringent requirement for the convergence time than intuitively expected, even in a jamming environment where the phase noise amplitude is large. This finding can be useful for practical design of GPS-based systems in a jamming environment, for which the ambiguity resolution time for precise positioning may be critical.     

GCM Hindcasts of SST Forced Climate Variability over Agriculturally Intensive Regions

The NASA/Goddard Institute for Space Studies (GISS) climatemodel is forced with globally observed sea-surfacetemperatures (SST) in five simulations, 1969–1991,with individual runs beginning from altered initialatmospheric conditions. The interannual variability ofmodeled anomalies of the Southern Oscillation Index,mid-tropospheric temperatures, 850 mb zonal winds andOutgoing Longwave Radiation over the tropical PacificOcean, which has the largest SST anomaly forcing, arestrongly correlated with observed trends which reflectENSO cycles. The model's rainfall variability overthree agriculturally intensive regions, two tropicaland one mid-latitude, is investigated in order toevaluate the potential usefulness of GCM predictionsfor agricultural planning. The correct sign ofZimbabwe seasonal precipitation anomalies was hindcastwithin a useful range of consensus only for selectseasons corresponding to extreme ENSO events for whichanomalous circulation patterns were ratherrealistically simulated. The correlation betweenhindcasts of Nordeste monthly precipitation andobservations increases with time smoothing, reaching0.64 for 5-month running means. Consensus betweenindividual runs is directly proportional to theabsolute value of Niño3 SST so that during ElNiño and La Niña years most simulations agreeon the sign of predicted Nordeste rainfall anomalies.We show that during selected seasons the uppertropospheric divergent circulation and near surfacemeridional displacements of the ITCZ are realisticallyrepresented by the ensemble mean of the simulations.This realistic simulation of both the synopticmechanisms and the resulting precipitation changesincreases confidence in the GCM's potential forseasonal climate prediction.     

Very-Large-Scale Motions in the Atmospheric Boundary Layer Educed by Snapshot Proper Orthogonal Decomposition

Large-eddy simulations of the atmospheric boundary layer (ABL) under a wide range of stabilities are conducted to educe very-large-scale motions and then to study their dynamics and how they are influenced by buoyancy. Preliminary flow visualizations suggest that smaller-scale motions that resemble hairpins are embedded in much larger scale streamwise meandering rolls. Using simulations that represent more than 150 h of physical time, many snapshots in the \(xy\) -, \(yz\) - and \(xz\) -planes are then collected to perform snapshot proper orthogonal decomposition and further investigate the large structures. These analyses confirm that large streamwise rolls that share several features with the very-large-scale motions observed in laboratory studies arise as the dominant modes under most stabilities, but the effect of the surface kinematic buoyancy flux on the energy content of these dominant modes is very significant. The first two modes in the \(yz\) -plane in the neutral case contain up to 3 % of the total turbulent kinetic energy; they also have a vertical tilt angle in the \(yz\) -plane of about 0 to 30 \(^\circ \) due to the turning effect associated with the Coriolis force. Unstable cases also feature streamwise rolls, but in the convective ABL they are strengthened by rising plumes in between them, with two to four rolls spanning the whole domain in the first few modes; the Coriolis effect is much weaker in the unstable ABL. These rolls are no longer the dominant modes under stable conditions where the first mode is observed to contain sheet-like motions with high turbulent kinetic energy. Using these proper orthogonal decomposition modes, we are also able to extract the vertical velocity fields corresponding to individual modes and then to correlate them with the horizontal velocity or temperature fields to obtain the momentum and heat flux carried by individual modes. Structurally, the fluxes are explained by the topology of their corresponding modes. However, the fraction of the fluxes produced by the modes is invariably smaller than the fraction of energy they contain, particularly under stable conditions where the first modes are found to perform weak counter-gradient fluxes.     

Magmatic and metamorphic evolution of the Shotur Kuh metamorphic complex (Central Iran)

Metamorphic basement rocks, that are exposed beneath the very low-grade to unmetamorphosed Upper Jurassic-Eocene formations north of the Torud fault zone within the Great Kavir Block, were investigated to elucidate the origin of their protoliths and the pressure and temperature conditions of metamorphism. The basement, previously assumed as a pre-Cambrian metamorphic complex, is mostly formed by amphibolite-facies orthogneisses (tonalite, granodiorite, and granite) with amphibolites and small amounts of metasediment-micaschists. Major- and trace-element geochemistry in combination with U–Pb age dating of zircon showed that the protoliths formed during Late Neoproterozoic continental arc magmatism that has also been identified in other tectonic blocks of Central Iran. In addition to quartz, feldspar(s), micas in orthogneisses, and amphibole + plagioclase in amphibolite, all rocks may contain garnet that shows prograde zoning. Kyanite was found only in some Al-rich amphibolite together with gedrite. The PT conditions of the rocks, based on conventional geothermobarometry and the pseudosection method, show a medium-pressure amphibolite-facies metamorphism. Ar–Ar age dating of muscovite reveals that this metamorphism occurred in the Middle Jurassic (166 Ma) and related to the closure of the Neotethyan basin.