In cities, rapid growth changes how water flows, leading to increased risk of flooding. To manage this, researchers used computer models to simulate runoff from rain in part of Tehran. They tested different green infrastructure methods like green roofs and rain barrels. By combining two models, they found the best solutions. A scenario with rain barrels, permeable pavements, and rain gardens reduced runoff by 72% with a cost of $2.12 million, the most effective option. Another scenario reduced runoff by 34$1.7 million. This study helps city managers and decision-makers design and optimize low-impact development solutions for managing urban runoff more effectively and affordably.