On 11/20/2015 9:00 AM, songbird wrote:
David E. Ross wrote:
...rainwater capture, swales, seeps, soaks, etc...
Where I live, the soils are so mineralized that any ground water
(including captured rain) is unfit for agricultural use, let alone
domestic use. We do have seeps and springs in the area. During a
drought about 30 years ago, however, a study determined that mixing only
one part of ground water with nine parts of California Water Project
water would yield something that would be illegally tainted.

that sounds rather extreme, but i'd assume
the native plants manage.

rainwater capture in barrels and lined ponds would
be another option for such an extreme case. water
right from the roof and other hard surfaces would
avoid most of the problem.


songbird


I recently had my roof's rain gutters cleaned. The gunk removed would
likely be harmless to my garden but would definitely not be potable.
There were several years of ash fallout from brush fires and Italian
cypress needles from my neighbor's trees. I often hear squirrels
running across my roof, so I would not be surprised if the gunk included
squirrel droppings.

After a long period without rain, the public is advised to avoid Pacific
beaches near storm drain outlets. For the same reason, the first rain
on my roof -- even after having my gutters cleaned -- is not very good.

In the fall, I use large amounts of gypsum to make my clay soil more
porous. I also mechanically aerate "lawn" areas, which are NOT grass
but a drought-tolerant ground cover. All this is an attempt to capture
rainfall to irrigate my garden.

In 2005 during an exceptionally heavy rain storm, the hill in my back
yard failed. In repairing it, two concrete V-ditches were built. One
runs across the top of the slope and feeds into another that runs down
the middle to a catch box at the bottom. Additionally, drain lines were
buried at four levels across the slope. I questioned the fact that
three separate lines were to be installed to covey water from the slope
to cutouts in the curb at the street in front of my house: one from the
catch box and one each from the drain lines on the left side and right
side of the slope. I was told the county (from which I needed a grading
permit) would not approve allowing the water to flow into my garden. By
the way, the damage is not insurable; the cost of repairing my hill
amounted to four times what I paid to buy my house.

--
David E. Ross
Climate: California Mediterranean, see
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary