## 5 Conclusions  
In Pakistan, there have been several shifts in groundwater management. Initially the focus was on managing the high water tables in the canal command areas, followed by a diversion in focus to encouraging private tube well development for increasing agricultural income [41]. Presently, the focus is on protecting aquifers from pollution and unsustainable pumping. National Water Policy (NWP) 2018 [42] emphasizes the establishment of monitoring networks to set sustainable groundwater yields and avoid the vertical movement of saline water. As per the NWP, provincial governments have to regulate and develop policy frameworks for sustainable groundwater management. The first step  
Figure 11: (a) Depth to water table for October 2035 with pumping density of 5 wells/100 ha. (b) Depth to water table for October 2035 with pumping density of 10 wells/100 ha. (c) Depth to water table for October 2035 with pumping density of 20 wells/100 ha. towards the formulation of effective policy is to generate knowledge about groundwater use and demarcate critical areas for groundwater management. Of the freshwater lenses in the northern Rohri canal command, Sindh is a critical area for groundwater management as the livelihood of its community is highly dependent on the use of fresh groundwater. Its overexploitation will have huge impacts on the livelihood of the community. It is essential that this lens be monitored and regulated for sustaining the livelihood of the community. In this study, we designed monitoring networks for freshwater lenses using a four-step approach. In the first step, groundwater levels were simulated. In the second step, sampling was performed in a hexagonal pattern. In the third step, PCA was applied at temporal levels, and wells with low variance were removed; and in the last step, minimization of wells was performed for representation of potentiometric contours. The key outcomes, limitations, and future prospects from the study are:  
* A hexagonal sampling pattern resulted in a 195 well monitoring network, which represented the area with a mean error of 0.098 m compared to the base case. * PCA resulted in a 135 well monitoring network, which represented the area with a mean error 0.318 m.
* Well reduction based on the contour classification resulted in a 59 well monitoring network, which represented the area with 0.61 m of error. * Three networks are presented for monitoring and management of the freshwater lenses, which can be established based on the available budget and monitoring targets. One with 195 wells will fully represent the water levels in the freshwater lenses. Designs with 135 and 59 wells will represent the depleting area, but they will not capture the water logging area. As the objective is to monitor the over-exploitation of the freshwater lenses, monitoring networks with 59 wells will help to achieve this objective. * The objective of this study was to model groundwater hydraulics and design a groundwater level monitoring network that can represent depleting and increasing water levels. As per the physical setting of the aquifer in the LIB, saline water up-coning will take place if the thickness of shallow freshwater lenses becomes thin following over-extraction [27; 28; 43; 44]. It is essential to set a water level threshold that should be kept in freshwater lenses to avoid saline water intrusion. In future studies, we will extend the flow model to perform freshwater-saline water interaction to set a groundwater level threshold. Water level measurements in combination with thresholds will provide regulators with a decision tool to regulate pumping in freshwater lenses by only monitoring levels in the piezometers. Conceptualization, W.A. ; Data curation, S.S.; Formal analysis, W.A., Z.A.R. and S.S.; Funding acquisition, W.A., A.L.Q. and J.F.P. ; Investigation, W.A. and Z.A.R. ; Methodology, Z.A.R. and C.A.O. ; Project administration, A.L.Q. ; Supervision, C.A.O. ; Writing--original draft, W.A. ; Writing--review & editing, C.A.O., A.L.Q., J.F.P. and M.A.