VISHAL BOREWELL DRILLING SERVICE

Pumping test consists of pumping a borehole at a specified rate and recording the level (and therefore the draw-down) in the pumping well, as well as any nearby observation boreholes at specific time intervals. When these measurements are substituted in appropriate flow equations, certain hydraulic parameters can be calculated. These parameters, together with qualitative assessment of discharge-drawdown characteristics, are then used for the assessment of a recommended yield of the boreholes and or aquifers.
Step Test
During this test the pump rate is increased in steps at regular intervals. For example a borehole may be pumped at a rate of 1000l/hr for a period of 1 hour and increased thereafter to a rate of say 2000l/hr for the next hour and so on for several more steps. This type of test is particularly useful to determine the effectiveness of the borehole, but not useful in determining the long term sustainable yield of a borehole. In this regard the constant rate test is more useful.
Constant Rate Test
In the Constant Rate Test (CTR), the borehole is pumped at a constant discharge rate over a period ranging from 8 – 48 hours (or longer) – the length of the test is normally proportional to the expected yield and importance of the borehole. The discharge is kept constant for the duration of the test and water levels are recorded in the pumping boreholes as well as observation boreholes (if any). The time-drawdown data obtained from the CRT is then analyzed. The analysis provides useful input to assess the sustainable yield of individual boreholes and the potential of aquifers. Hydro-geologists are trained to utilize different mathematical equations to estimate a sustainable yield.
Recovery Test
In this test, recovering water levels are measured in the pumping borehole immediately after the CRT, when the pump is switched off. This recovery test is very useful in assessing the pumping effect and possible dewatering of the aquifers that may result due to the limited extent of an aquifer.
Furthermore the recovery test will indicate the level to which the aquifer is actually dewatered by measuring the residual drawdown after the borehole was allowed to recover.
If you want to know your borewell yield, contact Vishal borewell Drilling.

It is reported that over a long period of constant use the yield of bore well/tube well declines. The clogging of well screens in tube wells and also cementing of clay particles in case of limited number of fractures would be the reason for this situation. In some other cases falling of silt and sand size particles due to the transient flow inside the pipes reduce the yield of the well and making pumping difficult. The remedy is to clean the well with water jetting or pressure injection called flushing.
To clean your borewell contact Vishal borewell Drilling.

Site selection for bore well drilling includes certain mandatory efforts.:

•  The Groundwater consultant should understand the litho logy of the area where activity needs to be performed.
•  Understanding the current depth of the bore wells in the region. Understanding the amount of water source at each stage of aquifer would be an added advantage.
•  Practical selection of the low lying areas and identification of the meeting point of rocks and a geological compass dip test is done.
•  Electrical sounding, magnetic resonance or induced polarization method of earth’s resistivity is plotted for each and every 30 feet.
•  Based on the change in resistivity scale following to various depths the least resistivity depths are taken into count.
•  The depths where least resistivity counts encountered are compared with the pre borehole logs of the region.
•  The very least resistivity encountered values are calculated with permeability ratio and also with the scale of satellite maps to understand better.
•  A minimum of three different stations are selected by the above process & based on the positive signs through all the above comparisons’ the best point is selected for drilling the borewell.

Although Pseudo scientific methods of groundwater investigations have led into success. A scientific Groundwater exploration at least gives a fair Idea about the depth aquifer conditions & the actual station condition in prior to drilling.
The role of geophysical methods in Groundwater Exploration is vital. Its chief aim is to understand the hidden subsurface hydro geological conditions accurately and adequately. Since the base of any geophysical methods is the contrast between the physical properties of the target and the environs, the better the contrast or anomaly, better would be geophysical response and hence the identification. So, the efficacy of any geophysical techniques lies in its ability to sense and resolve the hidden subsurface hydrogeological heterogeneities or variation. Hence for groundwater exploration a judicious application or integration of techniques is most essential to become successful in exploration, technologically as well as economically. It is to be clearly conceptualized that groundwater cannot be detected directly by any one of the geophysical methods and therefore the interpretation is contextual and a broad understanding of the subsurface hydro geological condition is prerequisite.
To identify borewell location contact Vishal Borewell Drilling.

Well development is the process by which a borewell is cleaned and the permeability of the borewell is increased by removing fine materials like sand, clay deposits and rock cuttings accumulated in borewells and gravel packing provided around well screens.
It is also carried out to borewells which are facing reduction in water yield over a period of time to increase its yield. The reduction in yield can be due to clogging of pores spaces by silt and mineral deposits.
Usually it is done by:
Flushing and Over Pumping in the borewell or flushing the borewell with adequate air pressure. In hard rock areas, flushing is done after the drilling process for at least 2-3 hours by using compressed air before drilling is stopped. Most of the drillers avoid this as it is an additional task. This is an important process that must be finally performed before completion of the drilling process at any given site. Flushing using air pressure or over pumping the borewell are the methods normally employed to improve the yield of such borewells.
Bore Blasting is a technique which is used for opening up of fracture zones of borewells located in hard rock areas. Around 14 to 230kg explosives are used depending upon the depth at which the blast is to be carried out. It is usually carried out when a drilled borewell is dry and there is a potential to obtain water by opening up fissures in the rock at the specific site. This method could also affect the very existence of the borewell therefore taking professional help is must for choosing this method.
Hydro-fracturing is applying water under high pressure for the creation, propagation and cleaning of fractures and fissures deep in the rocky layer of the earth. Creation or extension of the fractures is done using very high pressure water pumped into the bore well with pressures reaching as high as 3000 PSI (pounds per square inch). It is one way of cleaning the blockage in the fissure and releasing water back into the bore wells. It can also open up the bore well to new fissures in the immediate vicinity not previously tapped by the bore well. A borewell camera is used to identify the fracture zones inside the borewell prior to the process. Hydro-fracturing is an expensive process which is normally adopted by Government Water Supply Departments. Recently, private agencies are also involved in providing such services.

Gravel packing is a sand-control method used to prevent the production of formation sand. Gravel packing is used in conjunction with hydraulic fracturing, but at much lower pressures. Formation sand is produced from the breakdown of formations where wells are located. This occurs particularly in formations made of sandstone, limestone, and other similar types of rock. The main goal of gravel packing is to stabilize the formation and maintain well productivity.
For gravel supply contact Vishal borewell Drilling.

There is always a question mark when it comes to water. We are in the century where we get profit by selling water. People think that borewells is the reason behind the depletion of the ground water level whereas the truth is they themselves is the reason behind this situation. Borewells helps in drilling the ground and getting water which is few depths away. But few people misuses this and goes beyond the rules to drill and exploit the natural ground water.
Increasing water level in borewell can be done in many ways:

•  Using filtered taps
•  Reusing the waste water from the filtered to washing and gardening purposes
•  Constructing a proper rainwater harvesting
•  Digging a small pit near the borewell and fill it with stones of different shapes and sizes. Channelize rain water into this pit. The water filling this pit will gradually percolate down the ground due to gravitational pull. There after this water which has entered the ground has no option but to saturate the soil below and benefit the nearest borewell to begin with
•  Construction of percolation tanks around the borewell area helps in re-storing and recharging the wells and borewells

Also, there is no such technique to measure the exact water level other than the approximate time estimate, pressure calculation, rope and sound method. The water for recharging the borewell has to be of good quality and should be without any contaminants Borewell recharging is the key technique to revive the water level in the borewell. Through this method, the water in the surface such as rainwater can be sent via a natural filter made of stones and sand. This way of sending water directly from the penetration pit to the borewell is known as direct recharge system. If your Borewell is dry and not getting enough water, then its time for Reboring the point. Indirect recharging is for well-functioning borewells which isn’t dry yet. This is to ensure the continuous availability of the surface water throughout the year.

Borewell vs open well
The choice between a borewell and an open well depends on various parameters like location, Land Structure, Usage, Cost, etc…Let’s look at the comparison between open wells and borewells and what should be your opt solution: Open wells provide less water compared to borewells. The level of contamination is immense. The water cannot be used for drinking or cooking purpose straightaway. The chances of accidents, kids falling are exceedingly high. The water extraction process from an open well is orthodox. And one needs to draw water using rope and pully. If old people or children need access to water, borewell is the solution.Open wells is not an environment friendly solution, also borewells are a long term solution.Open Wells were successful in Harappan Civilization. In the present world, borewells is the optimum solution. It provides regular access to water which is clean and safe to use.

Prevent depletion of water reservoirs and reduce over-exploitationWith the continuous increase in urban population, the people living in cities are facing the problem regarding fresh water supply. Underground water is one of the major sources of water in cities. But excess pumping of the groundwater and less recharging is causing imbalance in the water table. If the over-exploitation continues, the water of the reservoirs will get depleted, the wells will go dry and it will be difficult to get them replenished.
To prevent depletion of water reservoirs and reduce over-exploitation, it is very important to effectively recharge groundwater aquifers in large scale at residential, commercial and institutional buildings to percolate rainwater to water table.
Here are a few tips for recharging groundwater aquifers.

•  Recharging of bore wells- Bore wells can be recharged by directing filtered rainwater collected in filtration tank of the building to the wells. Rainwater is collected on the rooftop of the building and diverted to the filtration tank by drain pipes. In filtration tank water is filtered. First shower of the rain should be flushed out by separators.
•  Recharge pit- Recharge pits are small pits confined with brick or stone masonry walls with weep holes at regular intervals. These pits can be of any shape square, rectangular or circular. Filter materials should be filled at the bottom of the pit. The pit should be covered with perforated covers at the top. The capacity of the pit should be decided according to the catchment area, the intensity of rainfall and recharge rate of the soil.
•  Recharge dug wells- Dug wells are also used as recharge structure. Rainwater is diverted to these dug well from the catchment areas after passing it through a filtration bed. To enhance the recharge rate, it is very important to clean and desalt dug wells regularly.
•  Recharge trenches- Recharge trenches are suitable harvesting surface run-off. It is appropriate for small houses, gardens, playgrounds and roadsides, where the upper impenetrable layer of soil is shallow. The trench is dug in the ground and refilled with filter materials like pebbles, boulders or brickbats etc. The length of the trench depends on the expected run-off.
•  Percolation tanks- Percolation tanks are artificial recharge technique. In this method, a highly permeable land area is submerged to facilitate percolation to recharge the ground water. These can be built where land and topography are suitable.

There are a number of potential causes for reduced yield from a domestic or commercial water borehole. These may include, but are not limited to:

•  Mechanical Blockage: mechanical blockage occurs when small soil particles or by-products from the well-wall build up and cause blockages or reduced flow.
•  Chemical Encrustation: essentially the chemical version of a mechanical blockage, chemical encrustation occurs when chemical deposits build up on the well screen or gravel pack and restrict the flow of water.
•  Bacteriological Plugging: Bacteria and other micro-organisms can also clog a borehole.

While the steps that need to be taken in order to rehabilitate a borehole will vary depending on the nature of the cause for the blockage or reduced flow, the following steps constitute a brief overview of the traditional steps borehole rehabilitation could or would necessitate:

•  A survey of the borehole will be undertaken first – the surveyor may ask you questions such as:
  What was the initial depth of the borehole?
  What the original yield was like compared to the current, reduced yield?
  What is the diameter of the borehole?
  The surveyor may also test the pH level of the water and perform other such assessments as indicated in order to diagnose the cause of reduced flow.
•  The pumping mechanism and/or other removable parts will be cleaned with a chlorine solution.
•  The borehole will be drained of all water and will be thoroughly cleaned of all sediment and debris.
•  Any damage to the inside of the borehole will be repaired. If the damage is too extensive, the borehole may be re-lined as opposed to simply repaired/patched.
•  The well itself will now be cleaned with chlorinated water.
•  Should the borehole/well require chemical cleaning it will take place at this juncture. If the well needs to be chemically cleaned the process could take anywhere from 1 to 3 days and will mean the well needs to be dewatered thereafter in order to remove the chemicals and chemical residue.
•  The well/borehole will be disinfected. Chlorination is the most common method of disinfection undertaken.
•  Post chlorination the well/borehole will need to be dewatered. The water will be tested until chlorine levels are back below 0.5mg per litre.
•  The well/borehole will be resealed.