Impact of large diameter recharge wells for reducing groundwater depletion rates in an urban area of Lahore, Pakistan
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ORIGINAL ARTICLE
Impact of large diameter recharge wells for reducing groundwater depletion rates in an urban area of Lahore, Pakistan Muhammad Masood Ashiq1 · Habib ur Rehman2 · Noor Muhammad Khan1 Received: 23 January 2020 / Accepted: 16 August 2020 / Published online: 27 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The groundwater table in Lahore, Pakistan is rapidly declining due to the effects of increasing urban development and groundwater abstraction at unsustainable rates. As managed aquifer recharge (MAR) has the potential to reduce this declining trend, a trial MAR scheme using four recharge wells was established at a site within the Lahore city area. A flowmetre and observation wells were installed for monitoring of groundwater recharge through the recharge wells and a numerical model was established to assess the effects of the recharge wells on depletion rates. Before the installation of recharge wells, the average depletion rate for groundwater was 0.87 m per year, of which the rate was − 0.074 m per was in summer season and 1.05 m per winter season. After installing the recharge wells, the model showed that the average depletion rate for groundwater was 0.72 m per winter season based on the 2-month data that showed the reduced depletion rate due to the installation of large diameter recharge wells. Then, scenario modelling was carried out using the same rainfall data for both the cases, i.e., without and with recharge wells. It was analysed that the depletion rate could be reduced by 16.45% and 39.24% by installing four and ten recharge wells, respectively. The study underlines the importance of groundwater recharge through large diametre recharge wells to reduce the depletion rate of Lahore’s aquifer. Keywords Lahore’s aquifer · Managed Aquifer Recharge (MAR) · Recharge wells · Monitoring · Modelling · Groundwater depletion rate assessment
Introduction Water resources in Pakistan are limited and are likely to decline in the future due to the effects of climate and land use changes. Currently, much of the water in the country is obtained from the Indus Basin, which generates 190 k m3 of water per annum on average (Bakshi and Trivedi 2011). Another source of surface water is the hill torrents in the mountainous * Muhammad Masood Ashiq [email protected] Habib ur Rehman [email protected] Noor Muhammad Khan [email protected] 1
Centre of Excellence in Water Resources Engineering, University of Engineering and Technology, Lahore 54890, Pakistan
Faculty of Civil Engineering, University of Engineering and Technology, Lahore 54890, Pakistan
2
areas of the country which have a total potential of about 23 km3 per annum. The unconfined aquifer of the Indus basin, from its mountainous north to the plains in the south, has an aquifer recharge potential of almost 61.67 km3 per annum while in Baluchistan it is almost 1.23 km3 per annum. Moreover, this groundwater recharge potential is being misused to 47.48 km3 out of 63 km3 (Kahlown and Majeed 2003).
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