Assessment of village-wise groundwater draft for irrigation: a field-based study in hard-rock aquifers of central India

Extracted groundwater, 90% of which is used for irrigated agriculture, is central to the socio-economic development of India. A lack of regulation or implementation of regulations, alongside unrecorded extraction, often leads to over exploitation of large-scale common-pool resources like groundwater. Inevitably, management of groundwater extraction (draft) for irrigation is critical for sustainability of aquifers and the society at large. However, existing assessments of groundwater draft, which are mostly available at large spatial scales, are inadequate for managing groundwater resources that are primarily exploited by stakeholders at much finer scales. This study presents an estimate, projection and analysis of fine-scale groundwater draft in the Seonath-Kharun interfluve of central India. Using field surveys of instantaneous discharge from irrigation wells and boreholes, annual groundwater draft for irrigation in this area is estimated to be 212 × 10⁶ m³, most of which (89%) is withdrawn during non-monsoon season. However, the density of wells/boreholes, and consequent extraction of groundwater, is controlled by the existing hydrogeological conditions. Based on trends in the number of abstraction structures (1982–2011), groundwater draft for the year 2020 is projected to be approximately 307 × 10⁶ m³; hence, groundwater draft for irrigation in the study area is predicted to increase by ～44% within a span of 8 years. Central to the work presented here is the approach for estimation and prediction of groundwater draft at finer scales, which can be extended to critical groundwater zones of the country.     

Determining Q of near-surface materials from Rayleigh waves

High-frequency (≥2 Hz) Rayleigh wave phase velocities can be inverted to shear (S)-wave velocities for a layered earth model up to 30 m below the ground surface in many settings. Given S-wave velocity (V_S), compressional (P)-wave velocity (V_P), and Rayleigh wave phase velocities, it is feasible to solve for P-wave quality factor Q_P and S-wave quality factor Q_S in a layered earth model by inverting Rayleigh wave attenuation coefficients. Model results demonstrate the plausibility of inverting Q_S from Rayleigh wave attenuation coefficients. Contributions to the Rayleigh wave attenuation coefficients from Q_P cannot be ignored when Vs/V_P reaches 0.45, which is not uncommon in near-surface settings. It is possible to invert Q_P from Rayleigh wave attenuation coefficients in some geological setting, a concept that differs from the common perception that Rayleigh wave attenuation coefficients are always far less sensitive to Q_P than to Q_S. Sixty-channel surface wave data were acquired in an Arizona desert. For a 10-layer model with a thickness of over 20 m, the data were first inverted to obtain S-wave velocities by the multichannel analysis of surface waves (MASW) method and then quality factors were determined by inverting attenuation coefficients.     

Alongshore Fluxes of Sand Sediments in the Region of Propagation of Tropical Cyclones (Example of the Hicacos Peninsula,Cuba)

Doklady Earth Sciences - The results of analysis of climatic peculiarities of the alongshore fluxes of bottom sediments are presented. The object of research is the coastal zone of the Hicacos...     

Kolmogoroff constants at the 1976 ITCE

The high-frequency data from 12 sensors at the ITCE 1976^* are analysed to determine the Kolmogoroff constants for velocity, temperature and humidity fluctuation, _u , _T , and _q . The occurrence of aliasing in the spectral analysis in some cases together with the limited response of some sensors at the higher frequencies introduces some uncertainties into the analysis. The Soviet sonic anemometer, fine-wire thermometer and infrared hygrometer and the Australian infrared hygrometer provide the best information, namely that% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaHXoqyda% WgaaWcbaGaamyDaaqabaGccqGH9aqpcaaIWaGaaiOlaiaaiwdacaaI% 5aGaeyySaeRaaGimaiaac6cacaaIWaGaaGymaiaacYcacaqGGaGaae% iiaiaabccacaqGGaGaeqySde2aaSbaaSqaaiaadsfaaeqaaOGaeyyp% a0JaaGimaiaac6cacaaI2aGaaGioaiabgglaXkaaicdacaGGUaGaaG% imaiaaikdacaGGSaGaaeiiaiaabccacaqGGaGaaeiiaiabeg7aHnaa% BaaaleaacaWGXbaabeaakiabg2da9iaaicdacaGGUaGaaG4naiaaiA% dacqGHXcqScaaIWaGaaiOlaiaaicdacaaIZaaaaa!6248!\[\alpha _u = 0.59 \pm 0.01,{\text{ }}\alpha _T = 0.68 \pm 0.02,{\text{ }}\alpha _q = 0.76 \pm 0.03\]where the errors quoted refer solely to statistical errors. The other instruments provide general support to these values.The technique of using spectral density measurements to determine eddy fluxes is illustrated.International Turbulence Comparison Experiment.     

The dynamical and liquid water structure of the small cumulus as determined from its environment

This paper examines the evidence for the model of a small cumulus cloud represented as a quasi static but turbulent entity, growing on the upshear side and decaying on the downshear side. While the air just outside the cloudy outline is, on average, stationary relative to the embedding airmass, there is a slight flow, upwards and forward as though the updraft has induced upward motion in the clear air outside the cloud, on the growing side. On the decaying side the motion is downwards and away from the cloud.This is a flow pattern which is not consistent with the air flowing around the cloud as it moves forward but it agrees well with the picture given. Decayed remnants of cloud are found throughout the air previously occupied by the cloud. The cloud outline moves through the embedding air at a velocity which is almost as large as the relative motion of the subcloud feeding airflow (which is almost free from internal wind shear in strong convection).The mixing of dry air from above the inversion yields the observed diluted liquid water content in small cumuli, if such mixing is allowed to proceed until the cloud density equals that of the surrounding air. Quantitative conditions relating the liquid water to inversion temperature and moisture changes, and to the stability of the environment are presented. The strong vertical mixing from the top of the cloud downwards is important to microphysical processes.     

Numerical Simulation Of Oil/Oily-Contaminant Migration And Entrapment In A Lenticular Reservoir

Numerical simulations show that water and oil/oily-contaminant migration are controlled by regional fluid-potential fields which may be modified locally by highly permeable lenses and buoyancy. In addition, fluid potentials are coupled to the distribution of oil/oily-contaminant via relative permeability and capillary-pressure curves. As saturation distributions evolve through space and time, so do the water and oil fluid-potential surfaces. The importance of capillary forces in oil contaminant migration and entrapment is illustrated by the fact that, in certain cases, lenses fill from above, even when the migrating fluid is lighter than water. Capillary forces operating in conjunction with lenticular reservoirs create excellent dynamic oil traps by allowing free passage of water, while retaining and concentrating oil. The analysis of oil (oily-contaminant) migration using numerical modeling and potentiometric-surface techniques is useful for the prediction of migration pathways and potential accumulation sites. On the other hand, identifying acatual accumulations from fluid-potential measurements (via inverse modeling) is not possible because fluid potentials are not uniquely dependent on saturation.     

Surface Photometry of Proplyds in the Vicinity of θ1 Ori C

Results of studies of the surface-brightness distributions of a group of young stellar objects located within 16″ of the star θ₁ Ori C are presented. Isophotes around each proplyd are constructed using violet, red, and near-infrared images. No regularity in the sizes of the diametral cross sections of the proplyds in the various photometric bands is observed. The measured relative intensities are converted to absolute fluxes, and the absolute luminosities of the brightest parts of the disks and of the disk peripheries are estimated. The ratio of the semi-major to the semi-minor axes of the objects range from 1.5 to 2.5. The maximum lengths of the proplyd tails in various filters range from 300 to 700 AU. They become shorter with decreasing distance from the illuminating star, possibly due to enhanced dissipation of the disk, due to the growth in the role of photovaporization.

     

15,000-yr pollen record of vegetation change in the high altitude tropical Andes at Laguna Verde Alta, Venezuela

Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced 15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the superpáramo. Although this community persisted until 6000 cal yr B.P., it began to decline somewhat earlier, in synchrony with cooling following the Holocene thermal maximum of the Northern Hemisphere. At this time, the pioneer assemblage was replaced by a low-diversity superpáramo community that became established 9000 cal yr B.P. This replacement coincides with regional declines in temperature and/or available moisture. Modern, more diverse superpáramo assemblages were not established until 4600 cal yr B.P., and were accompanied by a dramatic decline in Alnus, probably the result of factors associated with climate, humans, or both. Pollen influx from upper Andean forests is remarkably higher than expected during the Late Glacial and early to middle Holocene, especially between 14,000 and 12,600 cal yr B.P., when unparalleled high values are recorded. We propose that intensification of upslope orographic winds transported lower elevation forest pollen to the superpáramo, causing the apparent increase in tree pollen at high altitude. The association between increased forest pollen and summer insolation at this time suggests a causal link; however, further work is needed to clarify this relationship.     

Hydrogeochemical processes and quality assessment of groundwater in Dumka and Jamtara districts, Jharkhand, India

The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, anions (F^?, Cl^?, NO₃ ^?, HCO₃ ^?, SO₄ ^2?) and cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). The analytical results show the faintly alkaline nature of water and dominance of Mg²⁺ and Ca²⁺ in cationic and HCO₃ ^? and Cl^? in anionic abundance. The concentrations of alkaline earth metals (Ca²⁺?+?Mg²⁺) exceed the alkali metals (Na⁺?+?K⁺) and HCO₃ ^? dominates over SO₄ ^2??+?Cl^? concentrations in the majority of the groundwater samples. Ca?CMg?CHCO₃ is the dominant hydrogeochemical facies in 60?% of the groundwater samples, while 33?% samples occur as a mixed chemical character of Ca?CMg?CCl hydrogeochemical facies. The water chemistry is largely controlled by rock weathering and ion exchange processes with secondary contribution from anthropogenic sources. The inter-elemental correlations and factor and cluster analysis of hydro-geochemical database suggest combined influence of carbonate and silicate weathering on solute acquisition processes. For quality assessment, analyzed parameter values were compared with Indian and WHO water quality standards. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. Total hardness and concentrations of TDS, Cl^?, NO₃ ^? _, Ca²⁺ and Mg²⁺ exceed the desirable limits at a few sites, however, except NO₃ ^? all these values were below the highest permissible limits. The calculated parameters such as sodium adsorption ratio, percent sodium (%Na) and residual sodium carbonate revealed excellent to good quality of groundwater for agricultural purposes, except at few sites where salinity and magnesium hazard (MH) values exceeds the prescribed limits and demands special management.