Impact of Land Use Dynamics on Groundwater Table in Abbottabad city, Khyber Pakhtunkhwa (2008-2018)

Abstract

Abbottabad is one of the rapidly expanding cities in Pakistan.  Urban growth and the built environment have expanded during the past ten years, leading to an increase in impervious surface area and surface sealing, which has had a negative impact groundwater table (GWT). The purpose of the study is to assess the influence of expanding built-up environment on GWT in Abbottabad city. Satellite images of SPOT 5 for the year 2008, with a 5-m resolution were acquired from the Space & Upper Atmosphere Research Commission, Peshawar, while 2018 images were downloaded using the SAS planet platform. ArcGIS's maximum likelihood classifier method was used to classify these images into several LULCC. After calculating the area under various LULCC for both 2008 and 2018, the growth in the built-up was estimated. The GWT data for 67 tube wells, hand pumps, and dug wells for the years 2008 and 2018 was acquired from Public Health Engineering Department. The image analysis reveals that the built-up area of Abbottabad city expanded from 1575.1ha in 2008 to 1897.5ha in 2018. The study suggests that in various parts of the city the GWT is depleting at the rate of 0.17 to 4.00 feet per year. For a selected area of 219.26 acres, the computed runoff in 2008 was 0.583 cubic feet per second (cfs), while in 2019 it was 0.689 cfs. An expansion in the built-up area in 2019 is blamed for the rise in runoff because this trend speeds up runoff and reduces soil's ability to absorb water.