There are several types of water Cooling Tower.
You haven’t indicated the kind of Cooling Tower.
I’ve attached some sketches showing the everyday views of a multi-cell cooling tower, usually used in Energy Plants
The job can be completed in top ?usually 30 to 40 feet.
People who clear the nozzle will work by standing on the highest deck
For cleansing methodology and gear see the suggestion of the Cooling Tower manufacturer.
The physical situation of the highest deck must be ascertained so that people stand safely.
You have to take your engineer�s help to ascertain a cleaning process.