When using the Flood Studies Report (FSR) method to calculate rainfall intensity profiles, you need to two values. These are the rainfall depth of an M5-60 storm, in mm, and ratio of the M5-60 to the M5-two day storm event (Ratio R).

On the drainage size and level tools click the button.

M5-60 and Ratio R UK Map

Simply identify your site location on the map to determine the corresponding M5-60 and Ratio R values.

Navigating the Map

You can zoom in and pan the map with the mouse:

• Scroll Wheel: Zoom In and Out
• Middle Mouse Button: Click and hold to drag and move around the map.
• Left Mouse Button: Click once to set/change where you want to retrieve the M5-60 and Ratio R values from.

Clicking the left mouse button to select the desired site location will show a green cross where you clicked for confirmation. The M5-60 and Ratio R values will automatically show in the edit boxes below the map.

Zooming into the Map

To see more map detail, simply zoom in to the map using the scroll wheel and more place names will show on the screen, as indicated in the images below:

Placenames are colour coded:

• Red: Cities
• Green: Towns
• Purple: Suburban areas
• Light blue: Villages
• Grey: Hamlets

Typing in known values

Alternatively, if you know the values already, you can simply type the M5-60 and Ratio R values directly into the edit boxes below the map.

M5-60

The M5-60 value is the expected depth of rainfall, in millimetres (mm), from a storm lasting 60 minutes with a return period of 5 years.

Ratio R

The dimensionless ratio "r" value is the M5-60 minutes value divided by the M5-2 days value.

Click the OK button to confirm the values shown, or press the Cancel button to close the window without making any changes.

See Also:

• Contents
• Drainage auto-size and level