Perennial Aquifer Research Articles

Geo-physical attributes of Shushunia’s aquifer, Chhatna block, Bankura district, West Bengal, India

Shushunia hill lies in a transitional zone of the South Singbhum Mobile Craton and northern Gondwana formation. The Shushunia hill appears like a porcupine peak and it has structural similarity to the Eastern Ghat. The Shushunia hill zone is an example of a contact spring. In the foothill zone, two perennial springs are observed. The study purely deals with its aquifer and water quality. Based on the present rock strata and the nature of the contact aquifer, its early condition has been assumed. The discharge of the confined aquifers occurs by leakage. The water temperature depicts the springs are not of geothermal origin. Shushunia's aquifer is the shallow flow system water table and it is the subdued replica of surface topography. The comparatively high discharge rate during post-monsoon indicates the fractured conduit-water seepage towards the aquifer. Moreover, twin-contact aquifers do not yield water uniformly. The perennial aquifer may act as a municipal water supply source for drinking purposes in the future.

Vadose Zone Monitoring: Experiences and Trends in the United States

AbstractThe vadose zone is the portion of the geologic profile above a perennial aquifer. Inclusion of mandatory vadose zone monitoring techniques as an approach to aquifer protect ion was first proposed under the Resource Conservation and Recovery Act in the United States in 1978 and has since received increasing acceptance at federal and stale levels. The goals of a vadose zone characterization and monitoring effort are to establish background conditions, identify contaminant transport pathways, identify the extent and degree of existing contamination, establish the basis for monitoring network design, measure the parameters needed in a risk assessment, and provide detection of contaminant migration toward ground water resources. The benefits of vadose zone monitoring include early warning of contaminant migration, potential reduction of ground water monitoring efforts, reduction of contaminant spreading and volume, and reduced time and cost of remediation once a contaminant release occurs. Vadose zone characterization and monitoring techniques should be considered as critical hydrologic tools in the prevention of ground water resource degradation.

Groundwater processes, sandplain seeps and interactions with regional aquifer systems in South-Western Australia

Groundwater systems were studied in the 4200 ha East Belka catchment in a dryland farming area 300 km east of Perth, W.A., to determine the cause of sandplain seeps. Detailed investigations were carried out on a 200 ha hillslope to determine the characteristics of a shallow aquifer system responsible for the salinization of previously productive agricultural soils. The impact of the shallow aquifer on the regional system was investigated. A shallow (less than 8 m), perched, perennial aquifer was encountered in the deep sandplain materials. Groundwater discharge of about 1000 kl year −1 from the perched aquifer maintained saline soils across a 5 ha sandplain seep. Perching is due to the decreased permeability, geometry and silicification of the top of the mottled and pallid zones, and the convergence of perched ground waters near the seep. Slug test measurements suggest that the sandplain soils have a relatively low hydraulic conductivity (0.15 m day −1). Water qualities in the perched aquifer ranged from brackish to saline (3000–8000 mg l −1 TDS), peaking in the salt-affected area (12 000 mg l −1 TDS). High nitrate and Cl/Br ratios occur in the shallow aquifer and in the regional ground water beneath the sandplain seep. Recharge to the deep aquifer takes place throughout the catchment, but is greatest beneath the sandplain seep, where a perennial groundwater mound occurs. Recharge to the regional aquifer was estimated to be 6 to 15 mm year −1, increasing to between 20 and 60 mm year −1 beneath the seep. By contrast, less than 0.3 mm year −1 is able to leave the catchment as regional groundwater flow. Water-levels in the deep bores are consequently rising by 0.05 to 0.25 m year −1. Recharge to the deep aquifer beneath the seep, and low groundwater gradients, create the potential for groundwater flow to take place beneath the topographic divide and towards the adjoining catchment. However, as the vertical flux to the aquifer is two orders of magnitude greater than the horizontal flow, ground waters are effectively impounded within the catchment.

Management of sandplain seeps in the wheatbelt of Western Australia

Soil salinity in the wheatbelt of Western Australia is caused by discharge of groundwater both from regional groundwater systems and from perched, perennial aquifers. Perched groundwater systems have been studied in five catchments to determine the process responsible for the development of sandplain seeps and methods available for their reclamation. Groundwater interception using drains has been successful in reclaiming saline soils associated with sandplain seeps within 1–2 years. Stock quality water resources are available from these drainage systems. Storage in reservoirs is not recommended where the drainage water exceeds 400 mS/m. Where interceptor drainage is too saline for reservoirs, deeply buried tube drains provide a viable alternative to generate a stock water supply. Plantations of eucalypts are capable of intercepting groundwater and reclaiming sandplain seeps within five years. Evidence from one site suggests that 300 eucalypts were sufficient to intercept and transpire approximately 1000 m 3 of brackish to saline groundwater. Tree variety trials have been established and preliminary recommendations are available on suitable species.