Ground Water

Integrating geological concepts, such as relative positions and proportions of the different lithofacies, is of highest importance in order to render realistic geological patterns. The truncated plurigaussian simulation method provides a way of using both local and conceptual geological information to infer the distributions of the facies and then those of hydraulic parameters. The method (Le Loc'h and Galli 1994) is based on the idea of truncating at least two underlying multi-Gaussian simulations in order to create maps of categorical variable. In this manuscript we show how this technique can be used to assess contaminant migration in highly heterogeneous media. We illustrate its application on the biggest contaminated site of Switzerland. It consists of a contaminant plume located in the lower fresh water Molasse on the western Swiss Plateau. The highly heterogeneous character of this formation calls for efficient stochastic methods in order to characterize transport processes.

Cave diving is one of the most technical and potential dangerous forms of diving done today. It may involve use of multiple tanks, regulators and gas mixtures or rebreathers, in combination with powerful long-range diver propulsion vehicles, to penetrate thousands of meters into submerged cave systems where direct ascent to the surface in the case of emergencies is impossible. In order to carry out scientific studies under such difficult conditions, individuals must be highly competent and experienced cave divers. In spite of these problems, numerous scientific investigations in the fields of biology, ecology, microbiology, geology, hydrology and archaeology have carried out by cave diving scientists. Exploratory cave divers have provided the initial impetus for this research by exploring and mapping underwater caves.

In large canal irrigation project areas, integrated management of surface and groundwater resources can improve water use efficiencies and agricultural productivity and also control water logging. Such integrated management requires an estimation of spatial distribution of recharge and ground water flow in the underlying aquifer. Recharge occurs both as percolation losses from fields and seepage losses from the water distribution network. Percolation losses are influenced by weather, soil properties, land use, and canal water and groundwater use. Seepage losses depend on the conditions of flow in the water distribution system. In large irrigation project areas all the factors influencing the recharge of groundwater vary spatially. In this study, a geographical information systems (GIS) is used to map the spatial distribution of recharge which then serves as input to a regional groundwater flow model for simulating the behavior of the underlying aquifer. The basis is that the project...

Tracer techniques were used to study infiltration losses into a dry wadi bed. In order not to be fully dependent on rarely occurring natural flood events, an artificial flash flood was studied in a small arid stream channel, Nahal Shahmon, Israel. A reservoir was built, filled with water (550 m3) and breached artificially. Three different artificial tracers were injected at different times during the flood. At two locations downstream surface water samples were taken. The water moving within the alluvium was also sampled with the help of fluocapteurs distributed at different locations within the alluvial body. The fluocapteurs enabled the different pathways of the two dye tracers downstream to be identified and the maximum depth of infiltration to be approximated. This sampling technique is promising for future studies in arid rivers, since fluocapteurs can stay for a long time without any maintenance. Towards the end of flow, exfiltration from the channel alluvium was observed. The...

In recent years, several ponds near Alviso, California, previously used in commercial salt production, were modified for wetland restoration and management as part of the South Bay Salt Pond Restoration Project. Algal growth and subsequent decay often leads to suboxic or anoxic water conditions in the ponds. Sampling trips were coordinated in the second half of 2008 to examine the interstitial water in the sediment and the overlying bottom waters of three shallow (average depth

This is the first publication on arsenic contamination of the Red River alluvial tract in the city of Hanoi and in the surrounding rural districts. Due to naturally occurring organic matter in the sediments, the groundwaters are anoxic and rich in iron. With an average arsenic ...

The numerical growth of the population, together with the exponential growth of the consumer desire for specific consumption on the background of raising the standard of living, necessarily requires the identification of new solutions for the reconciliation of man-nature. On this background, the present study aims to analyse water quality within the Nature 2000 sites, viewed as strategic reserves, roles and functions in preserving and protecting biodiversity. The data required for the spatial analysis of water quality were obtained following the collecting and analysis of water samples by the Cris Basin Waters Administration from the relevant monitoring network. The spatial analysis implied the use of the ArcGis system in order to obtain spatial images, as well as the evolutionary tendencies of the water quality in the Nature 2000 sites, in Bihor County, Romania.

Abstract:
The prime objective of this research is to study and examine depletion of the groundwater and its effect on agriculture in Maharashtra for a period of last five year. Recent studies suggest the increasing contribution of groundwater depletion in Maharashtra. Groundwater depletion has more than doubled during the last decades, primarily due to increase in water demand, while the increase in water impoundments behind dams has been tapering off since the 1990s. It has gained substantial importance because of agricultural prosperity. Almost all water consumption needs are met from groundwater resources. In the last decades, rapid population growth coupled with agricultural expansion has significantly increased demand on groundwater resources. Large increases in water demand with little recharge have strained groundwater resources resulting in declines in water levels and deterioration of groundwater quality in the major parts of this region. It's worth mentioning the paramount cause of sharp drop in the groundwater table in recent years is conclusively attributed to pumping out of well water which confirmedly exceeds the level of the natural recharge.
The peninsular shield is mostly constituted of granites, gneisses, basaltic rocks of volcanic origin and metamorphic complexes. In basaltic rocks are devoid of primary porosity. The groundwater occurs largely in the secondary porosity of weathered mantle and developed at a shallow depth. These aquifers is mostly phreatic, occurring up to the depth 10 to 12 meter. These weathered mantle is underline by massive rocks which from the bottom of the phreatic aquifer, limiting its downward extent. The groundwater in the shallow aquifers gets replenished annually and therefore, the status of water levels and its fluctuation play a key role in assessment of groundwater. In recent decades there have been frequent conflicts between ground water Over-exploitation of the groundwater resources is the major problem leading to groundwater resources and environmentally hazardous activity. In the Deccan plateau of Maharashtra some districts are in the rain shadow zone. Groundwater-irrigated agriculture is the chief economic activity in this region. The lack of institutional arrangements and management instruments, government intervention is not likely to alleviate the crisis.

Timber production and wood products industries in the Mid-Willamette Valley of Oregon annually dispose of about 547,000 tons (500,000 tonnes) of wood and bark wastes. Land storage or disposal of these wastes can result in the generation of significant volumes of leachate.Wood waste leachates are commonly characterized by lignin-tannin (measured as tannic acid), oxygen demanding materials, color, and odor. In this study, lignin-tannin concentrations in the ground water ranged as high as 7.5 mg/l; iron and manganese were also shown to increase markedly relative to natural background concentrations, ranging as high as 13 mg/l and 106 mg/l, respectively.In August 1972 the area affected by the contaminated ground water covered about 4 acres (1.6 hectares) and extended nearly 1,000 feet (330 meters) downgradient from the disposal site. By late January 1973 the plume had migrated laterally to affect an area of about 15 acres (6 hectares) while extending over 1,500 feet (460 meters) downgradient. The lateral migration is attributed to a seasonal change in the local flow system. At least eleven existing domestic water-supply wells have been rendered nonpotable by this pollution.

The potential for chemical vapor intrusion from contaminated ground water to the interior of homes was investigated at a site with a leaking underground gasoline storage tank in Stafford Township, New Jersey. This location exhibited conditions favorable to vapor intrusion, with sand soil and a water table depth of 3.3 m. Concentrations of volatile organic chemicals in the ground water were as high as 82 mg/L for total benzene, toluene, ethylbenzene, and xylene (BTEX) and up to 590 mg/L for methyl-t-butyl ether (MTBE). Soil vapor samples at multiple depths were taken adjacent to several homes. Inside the homes, air samples were taken on the main floor, in the basement, and under the foundation slab. Despite high ground water concentrations, only one home had measurable impacts to indoor air quality attributable to some of the ground water contaminants. In this house, the BTEX chemicals were not detected in the basement, indicating a lack of indoor air impacts from the ground water for these chemicals. Oxygen measurements suggested that degradation attenuated these chemicals as they diffused through the vadose zone. However, MTBE, 2,2,4-trimethylpentane (isooctane), and cyclohexane were found in the indoor air. The first two of these chemicals served as gasoline-specific tracers and indicated that vapor intrusion was occurring. Attenuation factors (the ratio of the indoor air concentration to a source soil vapor concentration) for the BTEX chemicals between the ground water and the indoor air were <1 × 10−5, and for MTBE was 1.2 × 10−5. Attenuation factors between the deep-soil vapor and the basement air were as follows: BTEX compounds, <1 × 10−5; MTBE, 2.2 × 10−5; 2,2,4-trimethylpentane, 3.6 × 10−4; and cyclohexane, 1.2 × 10−4. Attenuation factors between the subslab vapor and the basement air were 7 to 8 × 10−3.

This paper presents a critical review of model-input parameters for transport of on-site wastewater treatment system (OWS) pollutants. Approximately 25% of the U.S. population relies on soil-based OWS for effective treatment and protection of public health and environmental quality. Mathematical models are useful tools for understanding and predicting the transport and fate of wastewater pollutants and for addressing water-budget issues related to wastewater reclamation from site to watershed scales. However, input parameters for models that simulate fate and transport of OWS pollutants are not readily obtained. The purpose of this analysis is to illustrate an objective, statistically supported method for choosing model-input parameters related to nitrogen (N) and phosphorus (P). Data were gathered from existing studies reported in the literature. Cumulative frequency distributions (CFDs) are provided for OWS effluent concentrations of N and P, nitrification and denitrification rates, and linear sorption isotherm constants for P. When CFDs are not presented, ranges and median values are provided. Median values for model-input parameters are as follows: total N concentration (44 mg/L), nitrate-N (0.2 mg/L), ammonium (60 mg/L), phosphate-P (9 mg/L), organic N (14 mg/L), zero-order nitrification rate (264 mg/L/d), first-order nitrification (2.9/d), first-order dentrification (0.025/d), maximum soil capacity for P uptake (237 mg/kg), linear sorption isotherm constant for P (15.1 L/kg), and OWS effluent flow rates (260 L/person/d).

The potential problems and their consequences due to fly ash disposal have been well studied around the world. Ash pond is a common available disposal facility for thermal power plants. The pond ash is subjected to weathering and the ions present in ash migrate to the soil ...