Estimating Groundwater Potential
Published on by Tejaswi Lakkundi, Associate Professor at Arba Minch University in Academic
What are the simple geobotanical techniques and methods that can be employed for estimating groundwater potential?
Which methods have you used for groundwater potential estimations?
Which methods are the most precise and which are the fastest but give a good enough estimation?
Taxonomy
- Groundwater
- Environment
- Hydrology
- Groundwater Recharge
- Groundwater Mapping
- Groundwater Resource
6 Answers
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I had done a study for the total cycle of water availability from the sea, precipitation flowing on various types of land use and back to the sea. In 1975, when I was working for the National Commission on Agriculture in India. Even the projections were indicated for the year 2000 and 2025. The availability held true upto the year 2000. Since then, due to increased population, agriculture, industry and urbanization, the utility of water in all forms has increased. To get a better idea for the future ground water can not be estimated without considering the land and other uses. Since then, only local information may be worthwhile for ground water. Such studies have to be repeated taking all these factors into account along with climate change, environment and ecology, as land use is changing fast. A copy of the annexure of the study is attached.
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Rainfall is the most important source of ground water recharge in the country. The most commonly used methods for estimation of natural ground water recharge in India include empirical methods, ground water level fluctuation method and the ground water balance method.Groundwater was the major source for irrigation prior to the introduction of canal irrigation system. Water contained in the voids of the geologic materials that comprise the crust of the earth is the groundwater. It exists at a pressure greater than or equal to atmospheric pressure. The experimental and mathematical methods required for analyses are distinctly different as it is exploited and used in human affairs in different ways. The important hydrogeological parameters such as porosity and hydraulic conductivity of the geologic stratum determine the performance of the aquifer. Added to this, an important factor is the length of data considered for predicting the groundwater potential. Thus, with adequate length of the database, the prediction of any derived model will reproduce the statistical properties. Otherwise, it is difficult to predict the regional groundwater flow conditions, subject to measurable hydrological, hydrogeological and meteorological variables in nature. As it is largely uncertain in nature, this cannot be left in isolationDifferent methods were proposed and many authors reviewed several applications on this problem. Rushton and Rathod (1985) have determined the velocity components from information about the groundwater-head distribution, groundwater potential, confined and unconfined aquifers; time-variant behaviour of aquifer and hydraulic conductivity. Mathematical models have been developed by Serrano and Unny (1987) as an innovative approach to the solution of groundwater forecasting problems considering the uncertainty generated by the use of data subject to environmental fluctuations and measurement errors. They have described in detail the development, solution and validation of two mathematical models describing groundwater potential at the Twin lake aquifer. Sondhi et.al. (1989) have determined the available additional groundwater potential and its distribution in the project area; estimation of groundwater recharge from the water conveyance and distribution system and the annual water balance of the project; 'recharge distribution coefficients' are done using digital simulation models. Chiew and McMahon (1990) estimated groundwater recharge using surface watershed modeling approach for both irrigated and non-irrigated areas. In all the above cases, they have not seen which time period will give appropriate prediction over the recharge value of a basin area. Uma and Kehinde (1992) described the analysis of the baseflow characteristics of numerous small basins to estimate the groundwater in the basins. Boonstra and Bhutta (1996) have worked on determination of seasonal net recharge considering temporal and areal recharge variations, geometry of aquifer system, historical water table elevations, drainage design and waterlogged areas, and developed numerical models for monsoon estimates, water-balance, and return period. A similar attempt is made here for estimating the ground water recharge potential of a river basin.
The commonly used method for estimating groundwater storage available annually is based on
Q = (Area) x (Depth of fluctuation in Groundwater Table) x (Specific Yield) (1)
In the above equation, the depth of fluctuation in groundwater table or the drop in groundwater table has to be calculated by taking the duration over which the fluctuation occurs
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бных скважин он может определить глубину залегания и объем запасов и приблизительный дебит воды рения пбуМой товарищ является автором метода, где без
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is the method documented/published?
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thanks for posting the powerpoint. it is interesting. the formula seems to be location specific (which is understandable). has there been any study in places like the Philippines (which as large and small islands, and the rainfall is very seasonal), central america (where in addition to rain, there would be water added due to streams/rivers etc.)?
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Vegetation could give you an indication of the type of soil on a large scale, these soils would be derived from underlying rock which have been subject to weathering process. Beware of man made vegetation landscape where vegetation and soil and geology will be distinct features. The link between vegetation and underlying groundwater is not conssitent and will be related to the most superficial type of groundwter. A geological map will/should give you a good indication of the hydrogeological potential in a first instance. This is usually confirmed by an exploration borehole which can be developped at a later stage. and according to the projected use.
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You may like to refer my article "Groundwater Assessment Methodology" at http://www.angelfire.com/nh/cpkumar/publication/Lgwa.pdf
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The link does not work for me. could you verify? regards
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Angelfire is working strange. Try this - http://www.angelfire.com/nh/cpkumar/ - Click on "My Publications" - Then click on "Groundwater Assessment Methodology" under Technical Notes.
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