On Sun, 12 Mar 2023 09:27:08 -0700, sms <
scharf...@geemail.com>
wrote:
>On 3/8/2023 7:29 PM, Jeff Liebermann wrote:
>> On Wed, 8 Mar 2023 10:19:14 -0800 (PST), Tom Kunich
>> <
cycl...@gmail.com> wrote:
>>
>>> All of the reservoirs in the state are at maximum capacity and southern California has a snowpack 250% of normal.
>>
>>> This latest rain that will stretch across the next week along with the earth so filled with water now that there are land and mudslides everywhere will soak down into the soil and refresh the water table.
>>
>> It's not enough for the ground water to return to normal. Even with
>> the current rain and snow, we are drawing more water out of the ground
>> than we are replacing it. Much of the state is still in some form of
>> drought:
>> "California Drought Map"
>> <
https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?CA>
>> "Lake Mead Water Database"
>> <
https://lakemead.water-data.com/>
>>
>> If the ground is genuinely saturated, then most of the upcoming
>> rainfall runoff will end up in the ocean and not in the ground. The
>> water table is only replenished when the ground is NOT saturated.
>
>This would seem to indicate that we need more and larger reservoirs.
Patience. It's only been on the agenda for about 70 years.
"New mega reservoir in final planning phase for California"
(Oct 19, 2022)
<
https://www.ktvu.com/news/a-new-mega-reservoir-in-final-planning-for-california>
"...it would be the seventh-largest mega reservoir."
>Another question I wondered about is the wisdom of drought surcharges at
>this time.
I think you mean "discharges", not "surcharges".
The wisdom behind discharging water is to make room for additional
water from subsequent rains. This is known as "flood control". The
discharges happen every year at the end of the rainy season, when the
supply of stored water and snow pack are known. Then, the amount to
be discharged can be better estimated. With some (not all) of the
reservoirs currently at capacity, and additional rain and snow melt in
the forecast, the discharge is happening early this year. If they
fail to discharge water and we receive additional rains, the
reservoirs run the risk of having the dam "topped" by water, which can
destroy the dam. The system and planning are not foolproof, as shown
by the draining on Lexington reservoir to clear out the plumbing, just
in time for an extended drought.
>If the reservoir water is being dumped into the bay and
>ocean, as it is now (saw it yesterday in Stevens Creek which was being
>fed by runoff from Stevens Creek reservoir) wouldn't it be better for
>residents to be using _more_ water from the reservoirs?
Yep. I'm taking extra long hot showers, washing my car and hosing
down the sides of my house. I'm all for water conservation and
austerity, but not during an oversupply. Incidentally, the local
water district seems to have finally switched from using ground water
back to surface water because the calcium content of the water is now
much lower. Even with the current series of storms, we are nowhere
near replenishing the underground water aquifers.
<
https://www.smgwa.org/SantaMargaritaBasin>
>The sewer water
>goes to a water treatment plant which puts the treated water into
>percolation ponds where it percolates down into the underground aquifer.
Yep. Lake Vasona in Log Gatos is a ground water percolation recharge
basin. Such ponds become necessary as the porous ground needed to
recharge the basin becomes sealed off by urban development.
Percolation is the key word here. The process is very slow.
>Or is there a connection between the reservoirs and the water treatment
>plant and treatment plan can't handle any more water?
I don't know. It's a complexicated topic. Not all the stored water
is treated. The larger dams and most of the water discharge is used
to generate hydroelectric power. Agriculture uses the largest share
of the water, mostly ground water, which also not treated. There are
also some water uses which require only filtered water, but not
treated. As always, cost and availability are the driving factors.
Note that the drought still covers much of California as well as other
parts of the country:
<
https://droughtmonitor.unl.edu/>
<
https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?West>
Also, Lake Mead, the source of much of our electric power, is still
dropping in water level and has not benefited from the rains:
<
https://mead.uslakes.info/level.asp>
Cheap hydro power might not be so cheap in the future.