**7. Groundwater management plan**

The management plan has been proposed to effectively manage groundwater resources and to arrest overexploitation [6]. The management plan comprises two components namely supply-side management and demand-side management. The supply-side management is based on surplus surface water availability and the unsaturated thickness of the aquifer, whereas the demand-side management is by the use of micro-irrigation techniques and changes in cropping pattern. In addition to this, in some parts of the district, groundwater development [7] is also formulated and recommended to authorities for implementation.

#### **7.1 Supply-side management**

The supply-side management of groundwater resources can be done through the artificial recharge of surplus runoff available within river subbasins and micro watersheds [8, 9]. Also, it is necessary to understand the unsaturated aquifer volume available for recharge. The unsaturated volume of the aquifer was computed based on the area feasible for recharge, the unsaturated depth < 3 m bgl, and the specific yield of the aquifer. **Table 5** gives the block-wise supply-side interventions through recharge structures.

The area identified for recharge measures in the district is worked out at 6334.28 sq.km.; however, in 5 talukas namely Igatpuri, Nasik, Peth, Surgana, and Trambakeshwar, there is no scope for aquifer recharge due to shallow post-monsoon water levels and rising water level trends. The total unsaturated volume available for artificial recharge is 25440.80 MCM, which ranges from 42.64 MCM in Dindorito to 8565.54 MCM in BaglanSatanataluka. Considering 75% efficiency the surface water required will be 33836.28 MCM, whereas the surface water available in the district is only 265.41 MCM, thus there is a huge shortfall of the surface water required for recharging the aquifers. The available surplus surface runoff water can be utilized for aquifer recharge through the construction of percolation tanks, check dams, gabion, underground bandharas, Nala bunds, continues contour trenches (CCT), and other site-specific structures; however, to arrive at specific numbers of the most feasible recharge structures, that is. check dams and percolation tanks were considered. The check dams of 10 TCM capacities with three fillings in a year and percolation tanks of 100 thousand cubic meters (TCM) capacity with two fillings in a year were considered to arrive at the number of the structures. Thus, a total of 649 percolation tanks and 1857 check dams are proposed with the available surface water resources. The tentative locations of these structures are shown in **Figure 22**.

#### **7.2 Demand-side management**

As seen above, supply-side interventions have limitations due to the limited availability of water sources, thereby hindering proper management of the aquifer


*Management of Hard Rock Basaltic Aquifer through Aquifer Mapping: A Case Study of Nashik… DOI: http://dx.doi.org/10.5772/intechopen.111644*

> **Table 5.** *Proposed supply-side*

 *intervention*

 *through aquifer recharge.*

**Figure 22.** *Location of proposed aquifer recharge structures.*

system. In such cases, it becomes imperative to adopt demand-side interventions and reduce our demand for groundwater by adopting micro-irrigation techniques. Generally speaking, traditional watering methods can lose as much as 50% or even more of the water applied as evaporation and infiltration losses. Whereas, the application of a micro-irrigation system (MIS) can increase yields and decrease water use, fertilizer quantity, and labor requirements [10]. In addition, other indirect benefits, such as significant energy savings, are observed, which are associated with the electricity required to pump water from the aquifer. The MIS system operates under low pressure, and according to the precise water requirement of the crop. Each dripper/ emitter supplies a precisely controlled quantity of water and nutrients directly to the root zone of the plant [9, 10].

The demand-side management is proposed in areas where the stage of groundwater development is relatively high and adopting micro-irrigation techniques for waterintensive crops or change in cropping pattern or both are required to save water [9]. In Nasik district, two major cash and water-intensive crops are proposed to be brought under drip irrigation, that is, sugarcane and onion. For sugarcane, the crop water


*Management of Hard Rock Basaltic Aquifer through Aquifer Mapping: A Case Study of Nashik… DOI: http://dx.doi.org/10.5772/intechopen.111644*

#### **Table 6.**

*Area proposed for drip irrigation demand side management.*

requirement by traditional flooding method is 2.45 m, and by drip irrigation, it is 1.88 m, thus a savings of 0.57 m (23%) can be achieved. Similarly, in the case of onion, the crop water requirement by the traditional flooding method is 0.78 m, and by drip irrigation, it is 0.52 m, thus a savings of 0.26 m (33%) can be achieved. Based on these calculations, the taluka wise demand-side management plan suggested for Nashik district is outlined in **Table 6**.

In Nashik district, an area of 116.84 sq. km. of groundwater irrigated sugarcane crop, and 790 sq. km. of onion crop is proposed to be brought under drip irrigation. The volume of water expected to be saved is estimated at 66.60 MCM for sugarcane and 205.40 MCM for onion, totaling 272 MCM of groundwater savings. The areas of sugarcane and onion, which can be brought under drip irrigation are plotted on the map and presented in **Figure 23**. If we compare, the groundwater augmentation by aquifer recharge measures is 139.30 MCM; however, water savings by micro-irrigation are much higher at 272 MCM. Thus, demand-side interventions are more beneficial, economical, and suitable for areas where there is limited source water availability for recharge and areas with high groundwater consumption for irrigation, especially cash crops and waterintensivecrops (**Figure 24**).

**Figure 23.**

*Areas proposed for demand-side interventions.*

#### **7.3 Expected benefits of aquifer management plan**

The impact of groundwater management plans on the groundwater system in the district after its implementation is evaluated, and the outcome shows significant improvement in the groundwater scenario in all blocks (**Table 7**).

The total groundwater resource available after supply-side interventions is 1989.21 MCM, whereas the total groundwater draft after the demand-side intervention is

*Management of Hard Rock Basaltic Aquifer through Aquifer Mapping: A Case Study of Nashik… DOI: http://dx.doi.org/10.5772/intechopen.111644*

#### **Figure 24.**

*Groundwater savings (MCM) due to supply and demand side interventions.*

809.66 MCM. Thus, about 582.79 MCM of groundwater is available, which can improve the stage of groundwater development by 17% from 58% to around 41%. With this, an additional area of 896.60 sq. km can be irrigated. The tentative locations of these areas are shown in **Figure 25**.
