**6. Behavior of multiple well points system and its applicability**

For monitoring the drawdown distribution in an aquifer while pumping through MWPS, piezometers were installed close to each well point and at the midpoint of the well spacing along the laterals. Each piezometer was of diameter 40 mm and was installed at a depth of 6 m. The piezometers installed near to well points were given names in accordance with their nearness to the respective well points. The symbol WLN indicates the Nth well point on the Lth lateral. The piezometers adjoining to the respective well points are named as PLN. For example, P23 indicates the piezometer near to the third well point on the second lateral (i.e., WLN). The piezometers installed at the midpoint of two adjacent well points along the lateral are named as PLN−L(N+1). For example, P23–24 represents the piezometer installed midway between the well points W23 and W24. The lateral L1 was discharging at a rate of 3110.4 m3 /d whereas the laterals L2 and L3 were delivering at a rate of 2419.2 m3 /d each. The available drawdown data were plotted and is presented in **Figure 13**. It is evident from **Figure 13** that the lowering of the water table is minimal at the four locations (i.e., in the center of the laterals at the outer boundary of the system). On the other hand, maximum lowering has been noticed around the central well points of middle lateral. Considering a section along the lateral lines L1 or L3 for the water table profiles, it is evident that the difference between the maximum water level at the midway between the wells and that of inside the wells was varied from 0.5 m at outer well to 0.72 m for central wells. These variations for L2 lateral were found to vary from 0.47 m at outer well to 0.87 m for central wells.

**Figure 13.** Behavior of multiple well points system while pumping.

Since the first type of problem was persisting in the project area, there was a need to control the water table first. Therefore, the pumping test was done with a schedule of 8 h of pumping and 16 h of recovery in a day for a week to observe the water table behavior in aquifer and soil. A residual drawdown of 17 cm in aquifer and 24 cm in soil was observed. It was also observed that the rise of water table in the soil during recovery is delayed with the passage of time. It could be explained as, once the water from soil is drained, rise would take place only after the pores of the soil are filled with water. It has imparted the delayed effect in rise of water tables in the soil. These encouraging results motivated us and long duration pumping of the aquifer was performed. Eventually, with the lowering of water table agricultural practices were started with the cultivation of paddy. Marginal quality water was used for irrigating the paddy which was achieved by mixing pumped water supply (through MWPS) with canal water. Studies show that the irrigation with marginal quality water does not affect the yield of paddy to much extent [30]. The motive was to continue pumping from the aquifer. In due course, groundwater quality in the upper portion of the aquifer started improving. In year 2002, groundwater samples were again analyzed for EC depth‐wise and are presented in **Figure 11**. Perusal of the comparison clearly indicates that the there is a drastic improvement in the groundwater quality in the upper portion of the aquifer. The excellent performance by the MWPS has proven that it is a viable technology for the region and needs promotion.

#### **7. Recommendation based on experimental results**

In order to propagate the use of MWPS in the region, a smaller system with four‐well points spaced at 6 m in a line connected horizontally at about 1 m below the land surface, pumped centrally was found to give technically satisfactory performance (i.e., no mixing of floating good quality water with the underlying poor quality groundwater) and economically viable results. Each well point has a screen length of 3 m which has 16% effective perforation and surrounded by pea size, well rounded clean river bed gravel envelope. Blind pipe may be adjusted according to the depth of aquifer. The details are shown in **Figure 14**. After watching the enthusiastic results of the project area, farmers of the region have adopted the recom‐ mended MWPS with four‐well points on a large scale. As per the survey of Faridkot district in year 2000–2001, around 1400 MWPSs have already been installed [36]. From the analysis of water quality samples taken from some selected MWPSs, it was found that these are with‐ drawing good quality water that is fit for irrigation. Farmers themselves have admitted that they are using MWPS from last 10 years and have not noticed any deterioration in pumped water quality. Moreover, the adoption of MWPS has also lowered the water table in the region.

**Figure 14.** Multiple well points system with four bore holes.

for central wells. These variations for L2 lateral were found to vary from 0.47 m at outer well

Since the first type of problem was persisting in the project area, there was a need to control the water table first. Therefore, the pumping test was done with a schedule of 8 h of pumping and 16 h of recovery in a day for a week to observe the water table behavior in aquifer and soil. A residual drawdown of 17 cm in aquifer and 24 cm in soil was observed. It was also observed that the rise of water table in the soil during recovery is delayed with the passage of time. It could be explained as, once the water from soil is drained, rise would take place only after the pores of the soil are filled with water. It has imparted the delayed effect in rise of water tables in the soil. These encouraging results motivated us and long duration pumping of the aquifer was performed. Eventually, with the lowering of water table agricultural practices were started with the cultivation of paddy. Marginal quality water was used for irrigating the paddy which was achieved by mixing pumped water supply (through MWPS) with canal water. Studies show that the irrigation with marginal quality water does not affect the yield of paddy to much extent [30]. The motive was to continue pumping from the aquifer. In due course, groundwater quality in the upper portion of the aquifer started improving. In year 2002, groundwater samples were again analyzed for EC depth‐wise and are presented in **Figure 11**. Perusal of the comparison clearly indicates that the there is a drastic improvement in the groundwater quality in the upper portion of the aquifer. The excellent performance by the MWPS has proven that it is a viable technology for the region and needs promotion.

In order to propagate the use of MWPS in the region, a smaller system with four‐well points spaced at 6 m in a line connected horizontally at about 1 m below the land surface, pumped centrally was found to give technically satisfactory performance (i.e., no mixing of floating

to 0.87 m for central wells.

60 Groundwater - Contaminant and Resource Management

**Figure 13.** Behavior of multiple well points system while pumping.

**7. Recommendation based on experimental results**
