Stormwater is the water from rain, snowmelt or melting of ice that flows across the surface. Stormwater collection systems must be designed to provide adequate surface drainage. The South West monsoon dominates weather patterns in Tamil Nadu, India from July - September and is characterized by periods of sultry wet weather. The start of the heavy rains usually falls in October lasting up to December. The study area is South West Chennai, including the Alandur, Pallavaram and Tambaram municipalities located in Chennai Metropolitan City in the Chennai and Kanchipuram district of Tamil Nadu. Most of the natural drainage channels are clogged with garbage and frequently used for solid waste disposal. In addition to this storm water disposal, lack of maintenance and inadequate carrying capacity exasperate the problem. The amount of storm runoff that is likely to be generated in the study area has to be estimated using the rational method. The Stormwater Management Model is a dynamic rainfall-runoff simulation model used for single event or long-term simulation of runoff quantity, primarily from urban areas. The routing portion of SWMM transports this runoff through a system of pipes, channels, storage, pumps, and regulators. The design of a storm water drainage network using the Storm Water Management Model will be effective in collecting and disposing of the runoff that occurs in the study area.

Figure 1: Indian Air Force Relief and Rescue Op during Tamil Nadu Flood, December 2015 (Chennai - water submerged bridges)

Figure 2: Conduit at high gradient level