**5. Installation of multiple well points system**

groundwater of the study area was not fit for irrigation. Hence, the project area was under the

A pumping test was conducted in a farmer's well which was existing in the project area. From the well log data, it was found that the depth of the soil at the location was 2.5 m and the aquifer was 10 m thick. Diameter of the well was 7.5 cm and it was installed in the said aquifer at a total depth of 10.5 m out of which 4.5 m was blind pipe of galvanized iron (GI). The well had a coir strainer of length 6 m. At a radial distance of 28.8 m from this well, another irrigation well of certain specifications was available which was used as a piezometer. Other than this available tube well, two more piezometers each of 9.0 m deep were installed at radial distances of 60 and 90 m from the test well, respectively. During the pumping test, the well was pumped at the rate of 10.82 l/s and drawdowns were recorded in all the three piezometers with respect to time. The change in drawdowns with respect to time at the three piezometric locations is presented in **Figure 12**. The recorded data were analyzed by the Walton method [35]. From the pumping test data, the average values of transmissivity *T*, hydraulic resistance *c*, and

The hydraulic conductivity of the overlying soil layers ranged from 1.4 to 2.0 cm/d.

**Figure 12.** Change in drawdown with time at three piezometric locations while performing pumping test.

/d, 17.04 d, and 0.0142, respectively [30].

first type of problem.

**4. Pumping test of the aquifer**

58 Groundwater - Contaminant and Resource Management

storage coefficient *S* were evaluated equal to 570 m2

It was proposed to install a battery of 24 wells constituting three laterals L1, L2, and L3 spaced 100 m apart. The well spacing along the laterals was considered to be 50 m with 8 wells on each lateral (**Figure 9**). The wells were installed by the local drillers. These wells were connected to each other at about 70 cm below the ground surface using 90 and 110 mm diameter PVC pipes by digging trenches. The screen of each well point had an effective perforated area of about 16% which is surrounded by pea size, clean, river bed, well rounded gravel pack of 30 mm thickness. In the middle of each 350 m long lateral, a T‐section was provided which was raised to the ground surface such that it remained in level with the ground after placement of reflux valve. The centrifugal pumps were connected with the aforesaid outlet points of three laterals. In order to prime the lateral, a reciprocating pump was placed over the delivery of each centrifugal pump. Initially, the air from the lateral was removed through the reciprocating pump and when there was an adequate flow of water, centrifugal pump was started. When‐ ever, there was disruption of flow, reciprocating pump was operated and was stopped when there was continuity in flow. Before covering the laterals with soil, the complete system was tested for any leakage. From the desired discharge rate and available head values, the power requirement to operate the system was evaluated equal to ∼4 hp (considering the working efficiencies of both centrifugal pump and diesel engine equal to 80% each). Therefore, three diesel engine operated pumps of capacity 5 hp each (nearest available higher size in the market) were installed on each lateral.
