Comparative Review of Hydrological Models for Runoff Estimation: A Focus on SCS-CN, TOPMODEL, and VIC Approaches– A Review

Abstract

Accurate runoff estimation is essential for effective watershed management, flood risk mitigation, and sustainable water resource planning. Over the decades, a wide range of hydrological models have been developed, differing in complexity, data requirements, and spatial–temporal resolution. This review provides a comparative evaluation of three widely used models—the SCS-Curve Number (SCSCN) method, TOPMODEL, and the Variable Infiltration Capacity (VIC) model with emphasis on their underlying structure, hydrological processes, applicability, and performance across various hydro-climatic and land use scenarios. The SCS-CN method, although empirical in nature, remains a preferred tool for event-based runoff estimation due to its simplicity and minimal data demands. TOPMODEL, a semidistributed conceptual model, links runoff generation to terrain-driven saturation dynamics, making it well-suited for humid and sloped watersheds. On the other hand, VIC, a semi-distributed, physically-based model, enables large-scale and climate-sensitive hydrological simulations by coupling water and energy balances within a grid-based framework. This review synthesizes recent literature to outline the strengths and limitations of each model, offering guidance for researchers and water managers in selecting appropriate runoff modeling tools based on watershed characteristics, modeling objectives, and available data resources