This column, explain details on steps by steps of OSD spreadsheet computation.
Step 1:- Open spreadsheet.
Step 2:- Change design ARIs value.
[Refer to table 4.1 in MSMA (2000).]
Step 3:- Change Coefficient value for a, b, c and d.
[Refer to table 13.A1 in MSMA (2000).]
Step 4:- Insert tc & tcs value.
[Refer to table 14.3 for area smaller than 0.4 hectare. For area larger than 0.4 hectare, please used formula stated in chapter 14.]
Step 5:- Insert FD values for short duration.
[Refer to table 13.3 and figure 13.3 in MSMA (2000).]
Step 6:- Insert area and runoff value for impervious and pervious area.
[Refer to design chart 14.3 and design chart 14.4 in MSMA (2000) for runoff coefficients value.]
Step 7:- The PSD & SSR value will be automatically calculated for you.
[Please choose type of OSD that you want to design and select the maximum value for SSR value.]
Editor:- Dilah – 10 March 14