% Function to estimate runoff volume at a shopping mall

function [runoff] = function_Runoff_rev(t)

global k1 k2 k3 k4 

% runoff is the runoff volume (cubic meters per second) 
% generated by the shopping mall  into the ponding area 
% t is the time (in seconds) after the thunderstorm starts

runoff = k1 * sin(t/k3) .* exp(-t/k4) + k2;
