The important methods that are available for drilling tubewells are as follows: 1. Percussion Drilling (Also Known as Cable Tool Method), further classified as: (i) Hand boring by rope or rod, and (ii) Mechanical boring with power rigs. 2. Rotary Drilling, further classified as: (i) Direct circulation hydraulic rotary, (ii) Reverse circulation hydraulic rotary, and (iii) Rotary-air percussion drilling. 3. [...]
In this article we will discuss about how to construct tube wells. Construction of Shallow Tube Wells: Shallow tube wells are constructed by boring, driving and jetting. The wells constructed by these methods are designated as bored wells, driven wells and jetted wells. These methods are briefly described below: (i) Bored Wells: Where, water table exists at a shallow depth [...]
The yield of an open well can be found by the following two practical methods or yield tests: 1. Constant Level Pumping Test 2. Recuperation Test. 1. Constant Level Pumping Test: In this test water is pumped from the open well so that the water level in the well is depressed by an amount h known as depression head (or [...]
The underground (or subsurface) sources of water are of the following four forms: 1. Infiltration Galleries 2. Infiltration Wells 3. Collector Wells or Radial Wells 4. Springs. From each of the first three forms relatively small quantity of groundwater is obtained and hence these may be considered as the minor forms of the underground sources of water. On the other [...]
Before pumping, the water level in the well stands up to the same elevation as the water table or piezometric surface depending on the type of aquifer. When pumping starts, the water is removed from the aquifer surrounding the well, and in and around; the well the water table or piezometric surface is lowered and assumes the shape of an [...]
Before pumping, the water level in the well stands up to the same elevation as the water table or piezometric surface depending on the type of aquifer. When pumping starts, the water is removed from the aquifer surrounding the well, and in and around; the well the water table or piezometric surface is lowered and assumes the shape of an [...]
A water well is a hole or shaft, usually vertical, excavated in the ground for bringing groundwater to the surface. Water wells may be classified as: 1. Open Wells or Dug Wells: Open wells are the wells which have comparatively large diameters but low yields (or discharges) and are not very deep. The diameters of the open wells usually vary [...]
In this article we will discuss about the formation of cavity in wells with the help of a suitable diagram. When the water is not withdrawn from the well, the water level inside the well is equal to the static water table outside the well. But when the water is being drawn from the well at some constant rate, the [...]
In this article we will discuss about the calculation of ground water yield with formula. When the water enters in the ground, it starts filling its pores. When all the voids of pores are filled with water, the soil is known as saturated soil or saturated formation. When the ground water soaked by the soil is drained or taken out [...]
The measurement of an open well yield can be determined by the following method: 1. Actual Pumping Method 2. By Theoretical Calculations. 1. Actual Pumping Method: The yield of well is determined by pumping out water from it. In this method first the water is withdrawn from the well at very high rate, then the rate of pumping is reduced [...]