Intensifying Drought Patterns and Agricultural Water Stress in Erbil Governorate, Iraq: A Spatiotemporal Climate Analysis

Drought is a prolonged lack of rainfall that causes water shortages for agricultural land by reducing soil moisture and limiting crop yields. This study assesses the impacts of drought in Erbil, Iraq, using 28 years of data from the southern, central, and northern regions. A soil-water-balance framework integrates precipitation with reference evapotranspiration (ETo), crop evapotranspiration (ETc), and actual evapotranspiration measures to address seasonal water deficits. According to the Standardized Precipitation Index (SPI), the area experienced basin-wide droughts in 1998-2000, 2007-2009, a renewed event in 2020-2021, and significant negative anomalies in 2024-2025. Analyzing drought frequency shows that "near-normal" conditions are most common (around 57%-79%), with occasional moderate to extreme events. The study reveals that winter wheat undergoes severe stress, with ETc reaching 200-250 mm month during dry years and ETa dropping to 15-30 mm/month, resulting in June deficits of nearly 277 mm. It also notes high variation in annual precipitation, with coefficients of variation (CV) ranging from 26.1% to 51.7%. ARIMA (1,0,1) models suggest weak persistence and zone-specific accuracy, with MAPE values of 37.8% in the south, 33.9% in the central region, and 28.8% in the north. The results underscore the importance of climate-resilient water and agricultural planning.