5 things you can do now to help you get the most from this winter’s rains

Here in San Diego, nearly all of our 10 inches average annual rainfall comes in the winter. How much water is that? If you use the formula of .623 gallons per square foot per inch of rain, that comes to about 26000 gallons per year that falls on our 1/10th acre lot. In other words – lots of water.

We have rain barrels to collect about 550 gallons, but what about the rest? Here are 5 ways to get started…

1) Watch this water harvesting presentation

Brad Lancaster gave a great speech at IPC10 in Jordan. His theme was Slow, Spread, and Sink the Water. If you’re a dryland dweller, it’s definitely worth 30 minutes of your time. He had some side by side photos of Tucson from long ago (before it was paved over) and today. He calculates that the annual rainfall that falls on Tuscon is greater than the municipal usage, but they have a ‘dehydration infrastructure’ – a paved system designed to move the water away as quickly as possible. He also presented much of what they’ve done to reverse that in his neighborhood.

2) Read Chapter 5 of Gaia’s Garden – Catching, Conserving and Using Water

It promotes the permaculture design principles of combining complementary techniques each of which is actually providing multiple benefits in the yard and garden. The one nugget that inspired me the most from this chapter was the explanation of how ‘sponge-like’ soil rich with humus and other organic matter is. The author, Toby Hemenway, had sterilized some rich potting soil by baking it in the oven. He had to rehydrate it. 3 quarts of soil held 1 quart of water. What does this mean for us? If we have 12 inches of rich top soil, the land can absorb and hold the first 3 inches of rain before any runoff begins. That’s a lot of water.

The basic components of the system described are:

  • high organic matter content – holds moisture, adds fertility, stores nutrients, and boosts soil life
  • deep mulching – slows evaporation, cools soil, adds fertility, boosts, soil life, and smothers weeds
  • use water conserving plants – need less water and survive drought (he provides a nice long list of Mediterranean plants)
  • dense plantings – shade the soil and smother weeds
  • soil contouring – catches water and directs it where it’s needed

The chapter really goes into some great detail on harvesting and using both rainwater and gray water. There are discussions of bigger projects like building swales and backyard wetlands as well as smaller efforts like mulching and rain barrels. It’s definitely worth the read…

3) Aerate the compacted walking areas

I’m not likely to be digging swales (well, maybe back in the canyon), so how to capture as much water as possible in the yards -which, yes, are still grass lawns. I suppose that all the little holes created by aerating the lawn will act like micro-swales to collect the rain and help it sink and soak into the soil. We have a aerator similar to the one in this picture. It works well and is good if your yard is not huge. It is pretty good good exercise and maybe the neighborhood kids can be recruited to help…

4) Amend the soil with organic matter

Here in San Diego, the dump has free compost they make from all the greens they pick up. If your city has curbside greens recycling, they may offer a similar service. They offer various grades of compost based on how long it’s been cooking and what size screen they used to filter it. You can get compost which has been processed for 10 weeks and screened to 1/2 inch for free if you load it yourself, or $12 per cubic yard if you have them load it.

5) Mulch Heavily

The dump also has mulch – similar to the compost program, but the mulch is only processed for 2 weeks. It’s graded at 4 inches and it’s only $5 for a cubic yard. A cubic yard is about a small truck load, and it looks like a lot while it’s in the truck, but a yard of mulch will cover a 10′ by 10′ area to a depth of three inches. The mulch ideally should be 4-6 inches thick, so you can adjust your expected coverage accordingly.

The keys to all this are to create entry paths for the water to get into the soil with swales or by aerating well, build organic matter into the soil to hold the water once it soaks in, and then mulch heavily to prevent evaporation.

What methods do you use to hold water on your property and reduce your consumption of municipal water? Do you have any other tips to suggest? Please add them in the comments below.

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