Assessment of groundwater level fluctuation using integrated trend analysis approaches in the Kapran sub-basin, North East of Iraq

Abstract

Groundwater extraction in the Kapran Sub-basin (KSB) has been intensified in recent decades due to population growth, urbanization, industrial activities, and agricultural expansion. Assessing water resources in KSB has become vital for researchers and local authorities to develop sustainable groundwater management strategies. This study aims to evaluate the spatio-temporal changes and trends of groundwater level using Innovative Trend Analysis (ITA), supported by non-parametric test techniques like Mann-Kendall (MK), modified Mann-Kendall (mMK) and Sen's slope estimator, along with Cumulative Rainfall Departure (CRD) to assess the relationship between groundwater level fluctuations and rainfall-recharge. Data from 10 monitoring wells (2000–2023), three rainfall stations (1941–2022), and 1053 production wells (2008 and 2023) were analyzed using geostatistical method. The results illustrate a strong linear relationship between the water level and topography, highlighting the aquifer's heterogeneity. The ITA and non-parametric analysis reveal a significant decline in groundwater levels, exacerbated by reduced rainfall (0.05–1.89 mm/year) and increased extraction (1.0 × 10^6 m³/day), with a decline rate ranging from 0.7 to 5.4 m/year. These findings provide (1) a robust scientific foundation for the stakeholders to efficiently develop sustainable strategies for integrated water resource management (IWRM) in order to mitigate the effect of climate change and GW abstraction, and (2) it provides local authorities and government in resolving groundwater scarcity in KSB.