How To: Golf Course Rainwater Harvesting Part 1

For golf courses using municipal water sources (roughly 14% in USA) or a limited renewable source for irrigation, collecting roof rainwater may have considerable benefits. Harvested rainwater can later be used to supplement landscape applications in isolated areas, for young planted material, the growing of nursery stock, bunker surrounds and heavily stressed turfgrass. Whatever your intended use, when evaluating the possibility of collecting rainwater from a roof for the purpose of holding and applying there are 3 major things to consider:

1. How much can I collect? (Supply)
2. What is the impact on my maintenance routines? (Collection, Storage & Demand)
3. How do I deliver? What is my ROI?

I’ve provided some insight to this process using a few helpful resources, case studies and formulas. Enjoy!

How much can I collect?

The simple formula to calculate a Rainfall Harvest is RH = [Harvestable Roof Area X Amount of Rainfall X  Rainfall Coefficient (material and slope)], this formula will help you if you choose to seriously evaluate the option of catching and storing rainwater. If you would like a simple way to see what your potential is then try out this free web-app at www.save-the-rain.com. You can get your answer in 3 easy steps:

1. Plug in your address, press "Go"
2. Find your building and click each corner of the building leaving a "point" on each corner. Press "Finished". This method measures the roof as if it were flat, which is a slightly more accurate approach then measuring the exact area as the pitch of the roof offsets the total area. Think of it as a harvestable footprint vs. total area.
3. Wait for the results... Eventually you'll get totals for the area of your roof, the amount of rain this area receives in a year, the amount harvestable and what this equals in toilet flushes, obviously we are not concerned with that last one if we plan on using this resource for irrigation purposes.
   Don’t like Litres? http://www.onlineconversion.com/volume.htm

There are a few other online calculators that can be found at these addresses:
Rainxchange.com An awesome calculator for Average Rainfall of US Cities, Roof Yield, Demand, Storage and Supplemental Supply Needed
Braewater.com Google Map Powered
EasyCalculation.com Just a calculator

Here are two Apps for the iPhone - sorry Android & BlackBerries, no App for you :(
Rain Harvest 
Rainwater Collection Calculator (meh)


See Part Two here.