Irrigation and water resources in the 1990's

Presented at Irrigation and water resources in the 1990's: proceedings from the 1992 national conference held on October 5-7, 1992 in Phoenix, Arizona.Includes bibliographical references.Since planning for droughts must be done in wet cycles, storing surplus surface water behind dams or in aquifers is essential. Underground storage is enhanced by increasing the infiltration of water into the soil, using in-channel and off-channel spreading systems and basins. In-channel spreading is achieved with low dams or weirs that increase the width and depth of streams, or by constructing T- or L-dikes in the streambed to spread the water over the entire width of the bed. Off-channel systems are mostly specially constructed infiltration basins or old gravel pits. Contrary to what may intuitively be expected, shallow basins tend to give higher infiltration rates than deep basins because there is less compaction of clogging layers that accumulate on the bottom due to suspended solids and biological activity. This is demonstrated with a soils engineering analysis and with field data. Artificial recharge can also be important in temporary storage of water, for example, in connection with seasonal changes in the use of sewage effluent for irrigation or in the demand for drinking water. For the latter, such aquifer storage and recovery generally is much less expensive than building water treatment plants with enough peaking capacity or surface storage. Artificial recharge also can play a role in the reuse of wastewater because it provides treatment benefits, gives seasonal storage, and improves the aesthetics of water reuse by breaking up the pipe-to-pipe connection of direct reuse

Ground Water Pollution and Emerging Environmental Challenges of Industrial Effluent Irrigation: A Case Study of Mettupalayam Taluk, Tamilnadu

Industrial disposal of effluents on land and the subsequent pollution of groundwater and soil of surrounding farmlands – is a relatively new area of research. The environmental and socioeconomic aspects of industrial effluent irrigation have not been studied as extensively as domestic sewage based irrigation practices, at least for a developing country like India. The disposal of effluents on land has become a regular practice for some industries. Industries located in Mettupalayam Taluk, Tamil Nadu, dispose their effluents on land, and the farmers of the adjacent farmlands have complained that their shallow open wells get polluted and also the salt content of the soil has started building up slowly. This study attempts to capture the environmental and socioeconomic impacts of industrial effluent irrigation in different industrial locations at Mettupalayam Taluk, Tamil Nadu, through primary surveys and secondary information. This study found that the continuous disposal of industrial effluents on land, which has limited capacity to assimilate the pollution load, has led to groundwater pollution. The quality of groundwater in shallow open wells surrounding the industrial locations has deteriorated, and the application of polluted groundwater for irrigation has resulted in increased salt content of soils. In some locations drinking water wells (deep bore wells) also have a high concentration of salts. Since the farmers had already shifted their cropping pattern to salt-tolerant crops (like jasmine, curry leaf, tobacco, etc.) and substituted their irrigation source from shallow open wells to deep bore wells and/or river water, the impact of pollution on livelihoods was minimized. Since the local administration is supplying drinking water to households, the impact in the domestic sector has been minimized. It has also been noticed that in some locations industries are supplying drinking water to the affected households. However, if the pollution continues unabated it could pose serious problems in the future

Determinación en el Campo, de la Conductividad Hidráulica, por Encima de la Superficie Freática, Mediante el Método del "Doble Tubo"

Fil: Bouwer, Herman. Instituto Nacional de Geología y Minería; Argentina

Internet firewall environment : an audit perspective

The aim of this article is to introduce auditors to the Internet, and more specifically to security implications for companies online. The article will look at firewalls as a control measure to protect these companies against the risks of the Internet environment. Guidance will also be given to auditors facing the challenge of auditing Internet firewall environments