Frequent questioning by the publics and reports on newspaper about the failure of stormwater drainage infrastructure and new opportunity to develop environmental protection regulations at provincial level encouraged to study on the need assessment for stormwater management guidelines in Pokhara city of Nepal. Analysis for the necessity of such guidelines was performed through different perspectives like quantity of runoff, failure of infrastructure services due to unmanaged drains, problems faced by the planners due to lack to integrated design and so on. In the study, the existing infrastructures were seen to be undersized in many areas, water being discharge to natural bodies were below the international practices and their standards and lack of defined polices and regulatory bodies for design, construction and operation escalated these types of social problems in the community. Similarly, the basic steps for estimating the storm runoff of the selected catchment and determining the size of stormwater drains has been discussed that aids to design of road side drains. Finally, rectangular stormwater drains are designed based on detailed hydrological study for Ward 2 of Pokhara city in Nepal. The need assessment study along with design examples to solve pragmatic challenges plays an important contribution to government authorities in Pokhara City as well as Gandaki Province to formulate guidelines for stormwater management.

Keywords : Flooding, Overflow, Road side drain, Flood management, Stormwater drain.