Abstract:
Flash floods which are becoming a common occurrence due to poor planning in the
urban areas need user friendly tools for land managers to arrive at suitable alternatives. These tools
require incorporating spatially distributed assessments performing several maps overlay and
hydrologic computations for the evaluation of runoff generation before and after a proposed land
development. The most common option for urban flood mitigation is the incorporation of land
allotment based detention storages. The land managers need to capture the optimum sizes for these
storages. A Hydro-GIS tool development was undertaken to ensure easy user friendly operation with
automation of complex hydrologic and GIS computations. The tool with the objective of targeting nontechnical
users’ demands high user friendliness and in order to achieve this, evaluations comparing
usability becomes very important. Identification of the right number of users to evaluate usability is a
requirement yet to be fulfilled. The present work successfully carried out a Hydro GIS tool
development for the management of urban land development, achieving its functionality objectives
while testing user friendliness with a user group of 23. Analysis shows that a group of over 13 users
would arrive at an on average problem area identification rate of 90% or more.
