Abstract:
Stream hydrology is highly affected by the dynamic behavior of the urban terrain due to urbanization In a
pre-developed setting, much of the rainfall is absorbed by the surrounding vegetation, soil and ground cover.
In a developed setting, the water balance changes and a disproportionate amount of rainfall becomes surface
runoff and causes flash floods. These excessive volumes are caused by both the total amount of impervious
cover as well as the rate at which the runoff is delivered to the stream. Kotuwegoda ungauged urban
catchment at Matara Municipal Council is frequently subjected to storm water induced flooding. In this
research, storm water flow of the existing channel network was modeled using mathematical model EPASWMM5.
Research comprises three basic steps as
Identifying the catchment parameters through field observation and Modeling. Using Arc GIS tool converting
model output to flood inundation area. Verify the results using field observations and making flood plain
management proposals.
