I'm heading up a group creating a new community garden in our small town (Saranac Lake, NY) and I'm trying to design a watering system that includes some water storage. I'm playing around with the numbers right now, and I'd appreciate any feedback from more experienced types.

Our garden is going to be 100' x 100'. Subtracting the alleyways, there will be ~8,000 sq ft that can be planted. I've read that the rule of thumb is 1 inch of water per week, and that .63 of a gallon covers 1 sq foot one inch deep. By my calculations, we have a need for 5,000 gallons a week of water.(If I assume that some of the area won't be planted, it could go down to, let's say, 4,000 gallons a week)

So, am I in the ballpark with my calculations? We have some restrictions on when we can water, so I'm thinking that two 300 gallon tanks could carry us for a couple of days, assuming not everyone waters every day.

Thanks for any input.