Rainfall Assessment and Water Harvesting Potential in an Urban area for Artificial Groundwater Recharge with Land Use and Land Cover Approach

Cities in arid and semiarid regions face the dual challenges of managing urban floods and water shortages, threatening their sustainability. Urban areas are particularly vulnerable to flooding despite minimal rainfall and are prone to drought. This is evident in the capital of Afghanistan, Kabul, where groundwater decline and urban floods pose severe challenges. This study investigates the possibility of utilizing rainwater harvesting (RWH) to manage urban floods and recharge groundwater. The research examines various aspects of rainfall patterns, such as variability, rainy days, seasonality, probability, and maximum daily precipitation. The analysis of precipitation statistics reveals that rainfall exceeding 30 mm occurs approximately every 3-4 years. Rainfall in Kabul follows a seasonal pattern, with a coefficient of variation of 127% in October and 46% in February during the wet period. The study then assesses the potential of RWH in Kabul City as a solution for stormwater management and groundwater recharge. Based on the typology of land use and land cover, implementing a rainwater harvesting and recharge system (RWHRS) could increase mean annual infiltration from 4.86 million cubic meters (MCM) to 11.33 MCM. A weighted Curve Number (CN) of 90.5% indicates impervious surfaces' dominance. The study identifies a rainfall threshold of 5.3 mm for runoff generation. Two approaches for collecting rainwater for groundwater recharge are considered: RWHRS for a residential house with an area of 300m2, which yields approximately 88m3/year, and RWHRS for a street sidewalk to collect water from streets and sidewalks. These findings highlight the potential of RWHRS as an effective strategy for managing urban floods and recharging groundwater artificially.

Automated summary

Cities in arid and semiarid regions face the challenges of managing floods and water shortages. A study in Kabul, Afghanistan investigates the potential of rainwater harvesting (RWH) to address these issues. The analysis shows that implementing RWH systems can increase infiltration and recharge groundwater, making it an effective strategy for flood management and artificial recharge.