12/11/05

 The first step I took was to calculate an estimate of how much water my plants would need. I discussed the issue with some local farmers and gardeners, and came to the conclusion that with mulching and cover crops I could reduce my water need to the equivalent of one inch of rain per month.  Using the average rainfall for Arcata during  June, July, August and September (the rest of the year we get more than enough rain) I calculated how much water would need to be saved during these months so that the plants could receive the equivalent of one inch of rain.

Rainfall Table

Since the size of my vegetable beds and storage areas were determined by an ongoing search for reused materials, the calculations, which are based on the fact that one inch on rain falling over one square foot of space is equal to 0.56 gallons, were done several times before the final version was complete.  The final plan includes three sections, each with catchment area, storage area, and watering area.

The blue area represents water to be held in the pond and it's route.  It will overflows down a pipe into the blackberries.  The grey area shows water expected to flow to the barrel in the back of the house.  The orange area shows the path of water to two barrels on the side of the house.  These are connected and will overflow into some bushes which already received the flow off of the roof.  The red area on the roof shows the barrier that prevents water flow. (discussed in catchment section) Yellow areas (that are supposed to be green) are the areas to be watered including an herb spiral, 4 beds, a hotbox made of reused windows, an apple tree, a pear tree, a fig tree, an apricot tree and two nectarine trees.

One constraint I faced in the design process was the existence of an 18 inch rock wall about a third of the way across the yard so that there is no down hill slope to the pond site. To deal with this, P.V.C. piping was attached to the fence ad an adequate slope to allow water to flow down to the pond.  It will be pumped out of the pond to the beds and trees with a solar pump.