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Ken M
Mountain climber
Los Angeles, Ca
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Oct 23, 2015 - 12:15pm PT
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I am particularly interested in things that individuals can do involving water. It's easy to get caught up in the concept of massive infrastructure that is built by the gov't---and it has it's place. But I also like to look at what people can do.
For example,
1. spread organic mulch. 10# of mulch or compost will hold about 50 gallons of water----just about what the average barrel will hold. Rain Barrels are a popular approach, but mulching all bare ground accomplishes the same thing, and many cities (like LA), furnishes mulch or compost (or both, as in LA), FREE OF CHARGE in unlimited quantities.
http://www.lacitysan.org/srpcd/mulch_giveaway.htm
2. Rainwater capture strip at edge of property (infiltration trenches). a one-foot wide strip of a foot deep of ornamental rock, or free mulch, provides a way for any runoff to enter the water table, instead of running off on the street.
http://www.sccd.org/Infiltration%20Trenches.pdf
3. Permeable driveways instead of impermeable. Again, a pathway for water to enter the water table. Do it when you build it (basically costs nothing extra), or when you have to re-do it.
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Reilly
Mountain climber
The Other Monrovia- CA
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Oct 23, 2015 - 12:19pm PT
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Permeable driveways instead of impermeable.
Ken, are you available to come talk some sense to my wife? She wants a new
concrete one cause it will be "better for resale." Oh, yeah? Maybe some
tree-hugger would want to buy the joint?
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John M
climber
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Oct 23, 2015 - 12:19pm PT
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Ken, In the mountains we have to rake up the pine needles near our homes in order to help protect against fire. Most do leave the needles further away from their homes.
As for permeable driveway.. how does that work. I had a dirt driveway in Yosemite. It was not very permeable because it was so compacted. Water just ran off it.
but I do like your thinking.. In India there has been a resurgence of small earth dams to help capture rainwater and build the water table. It seems to work. Maybe you were the one who posted about this. I saw an article or video about this. Pretty cool.
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johntp
Trad climber
socal
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Oct 23, 2015 - 01:37pm PT
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There was a day when infrastructure kept up with population growth.
I believe the developers take responsibility for this rather than the gubberment (us).
Dirtbags make a bundle and leave the mess behind, as in all the development along the 395 still being served by a 1970s road system.
edit: If they develop a 1000 home subdivision or mega mall, they should bear the responsibility and cost to provide adequate infrastructure, including water supply.
2nd edit: Ken; this is a long thread, apologies for missing your post.
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Ken M
Mountain climber
Los Angeles, Ca
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Oct 23, 2015 - 01:43pm PT
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John, I did post about that, thanks for noticing.
Reilly, have your wife check out this video on permeable concrete:
https://www.youtube.com/watch?v=-iJP7DFt6AU
The way it works is that they use coarser rock in the formulation, so the water runs right through. Underlying the top layer, is a big layer of 2-inch rock, which serves as a water basin, from which the water can drain into the underlying dirt.
The same thing can be done with interlocking pavers, spaced by simple sand.
As for replenishing the groundwater, some are thinking of that:
http://www.scpr.org/news/2015/10/22/55196/uc-davis-maps-farmland-that-can-bank-groundwater-d/
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August West
Trad climber
Where the wind blows strange
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Oct 23, 2015 - 01:56pm PT
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Dams are the WRONG concept for this age. The Dam age has passed.
First, all the good spots are taken. Already dammed up.
Second, many of the remaining spots are now used for other things, like cities.
I'm not keen on more dams. However, if NorCal gets more rain and less snow, building Auburn dam would make sense from a water supply perspective.
Groundwater recharge might make sense in some situations but during a large winter storm, it isn't going to be possible to get all that water into ground. A large peripheral canal could help get water south where it could be put into the ground but I don't know if the politics will ever allow for it.
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Fat Dad
Trad climber
Los Angeles, CA
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Oct 23, 2015 - 05:34pm PT
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William Mulholland was actually an early advocate for underground storage. The loss and salinity increase from evaporation (not to mention how costly and impact driven dams are) are major, unresolved problems. They've tried to address that at reservoirs in LA by covering them in large plastic balls, but that seems feasible only for small urban reservoirs.
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TGT
Social climber
So Cal
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Oct 23, 2015 - 06:03pm PT
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MWD has had floating covers on huge reservoirs for years. So long in fact that a contract is about to be let to replace one of them.
Lake Mathews, Skinner, Diamond are that though. Large amounts of state water system capacity does go into underground storage in years where there is excess capacity.
What will work is driven by local geology/hydrology (which is why in large the porous driveway idea is impractical and ineffective).
The SGV is one big sand pit and an easily rechargeable reserve, but that's a rather rare exception. Most groundwater should be considered a non renewable resource since the recharge times are on the scale of a hundred years or so,
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Ken M
Mountain climber
Los Angeles, Ca
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Oct 24, 2015 - 10:21am PT
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TGT, granted.
Except that we are not taking advantage of nearly all the recharge possibilities. Like the SGV, the San Fernando Valley is very porous, and overlies a great aquifer. Currently, 81 BILLION gallons of rainwater a year runs across that land area, and largely lands in the LA River, and thus, the Pacific Ocean. Actually, the surface area is quite a bit larger, when you count the mountains surrounding the SFV that drain into it.
Granted, huge rainstorms need to be evacuated, but most rainstorms are not huge. Most are under 1", and would be easily captured to a large degree. For example, in 2015, only one rain event exceeded .75 inches of rain:
https://www.climatestations.com/wp-content/uploads/2015/10/lacv2015.gif
According to this graph, since 1921, on only two days of the year are we likely to have greater than a 1" storm, and even then, only 7% of the time.
http://www.climatestations.com/images/stories/los-angeles/LACVPDAY.GIF
We, in LA, have already changed the building codes to require any new building to be able to absorb a 1/2' rain event onsite. It is easy to do, and costs virtually nothing to do in new building. The problem, of course, is existing building stock. And roads.
In my mind, the place to start is the northern San Fernando Valley, particularly in flood-prone areas. Build in absorptive structures in upstream areas, and get rid of the flooding in 90% of the rainstorms.
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Ken M
Mountain climber
Los Angeles, Ca
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Oct 24, 2015 - 11:01pm PT
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here is something else to think about: We are heading into this wet season shortly. What can we do NOW that will impact the capture of that water?
How long will it take to build a dam? 20 years?
However, if they got everyone to go out and spread mulch, that works RIGHT NOW. It is FREE, or nearly free.
A city spreads a million lbs. That will capture 6 million gallons for slow infiltration. If it rains 12 times during the year, that is 72 million gallons. If 50 cities do that, it is 3.6 BILLION gallons per year. Free.
In the 20 years, while we wait for the dam to be built, we can save 72 BILLION gallons of water, to replenish the aquifer. No transfer costs. No labor costs. No material costs.
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Dr.Sprock
Boulder climber
I'm James Brown, Bi-atch!
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Oct 25, 2015 - 03:17am PT
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no rain predicted for 300 years, plenty of time to build dams,
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TGT
Social climber
So Cal
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Oct 31, 2015 - 07:30pm PT
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If you live in the OC you already are.
http://www.ocwd.com/
Tertiary treatment for groundwater recharge is the most economical way to go. MWD and LaCO San are going forward with a project in Carson that will be even larger than OCSD's
There's another in planning for the SFV but I think that one is toilet to tap, mostly due to the complicated aquifer not really being amenable to storage by re-injection.
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Ken M
Mountain climber
Los Angeles, Ca
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Oct 31, 2015 - 08:44pm PT
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Actually, all the water imported from the Colorado River has been recycled many, many times.
And it makes sense---water does not get "used up", like gasoline that is gone when it is used.
The water is still there, although dirty. Clean it up, and it is perfectly usable again. and again. and again.
And we've had the technology to clean dirty water to purer than anything you can buy for about 50 years. It is NOT new technology.
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TGT
Social climber
So Cal
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Essentially it's the same process for recycled waste or seawater.
Just that since the salt content of treated wastewater is an order of magnitude or more lower so the recovery process is much less costly. On top of that the transport energy costs are much lower. You have to pump that desalinated water uphill from the ocean, (sometimes like the Carlsbad plant a long way uphill)to the point of use.
Treatment plants tend to be collocated with the point of demand so pumping costs are a lot lower also.
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Chaz
Trad climber
greater Boss Angeles area
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I have a Toilet-To-Guacamole program running here.
Avocados like nitrogen, so if your California Avocado tastes a little like espresso or IPA, you'll know whose grove it came from.
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Ken M
Mountain climber
Los Angeles, Ca
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I was at a conference last week, where the head of water for LADWP spoke, and he spoke directly to the issues that TGT mentioned, regarding cost of treatment of seawater v. dirty water.
It costs a bit over $2,000 per acre-foot for desal,
It costs around $500 per acre-foot for cleaning dirty water.
You end up with essentially the same product.
LA dumps into the ocean about 350,000,000 gal of very treated (secondary) water every day.
That is 128 BILLION gallons of water per year. Thrown away.
Because it is already partially treated, the cost of treating it to drinking standards would be much less than the $500/af.
The current water usage of LA is 450 Billion gallons a year. That's a significant percentage of tne need.
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August West
Trad climber
Where the wind blows strange
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I have no problem with cities treating dirty water and I agree they should. But cities don't really make that much difference. Agriculture consumes, what, around %80 of the water. It really comes down to growing almonds and avocados and how much water, if any, get left for fish and the environment. Cut you average shower in half and what, you might be able to grow one more almond.
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Ken M
Mountain climber
Los Angeles, Ca
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August,
It is a lot more complicated than that. Much of it has to do with the legal rights to water, which in Ca is complex. So complex that legal scholars who work in the area do not think it will be sorted out in their lifetimes.
Actions taken by cities can have a HUGE impact----on those cities! The cuts that LA has achieved during this drought has cut the amount of water used by 150,000,000,000 gallons. That much water does not need to be found to keep things going.
But there are bigger issues: the water that is brought over the Tehachapi Mountains to Socal is not used to water crops, but the lift of that water uses 10% of the power used in California. Not importing that water would eliminate that power use, almost all of which comes from coal.
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Dr.Sprock
Boulder climber
I'm James Brown, Bi-atch!
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the water is right and the weather is perfect,
lookey there, i got a bite,
fish more concentrated in drought stricken lakes, look at the brite side,
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