El Niño vs. the Drought | Hacker News Reader

El Niño vs. the Drought

medium.com

56 pointsfezz14 comments

Didn't do the homework.

The first thing to know about the California Water Project is that it's designed to store enough water for three dry years. Last year was year four. The last time that happened was 1976-1977. Agricultural water customers have had huge cutbacks in their water deliveries.

Right now, rainfall is more important than reservoir level changes. It takes time for the water to reach the reservoirs. Rainfall so far this year is slightly above average, after four years of below average. This is not enough to recharge the reservoirs; that will take about two wet years. It's also not that important how much is in which reservoir; most of them are connected.

Here's the drought contingency plan updated to February 13, 2016.[1]

Household water isn't a big problem. It's agriculture that's hurting. Especially low-value crops such as rice and alfalfa.

Orange County is already recycling water from their sewerage disposal plant into drinking water. San Jose has that capability with a new plant, but isn't using it for drinking water yet. (But if you take the tour there[2] you can drink some.) San Diego County's desalinization plant opened last December and is now providing about 10% of their water. There's a lot going on to deal with the problem.

[1] http://www.water.ca.gov/waterconditions/docs/2016-DroughtCon...

[2] https://www.eiseverywhere.com/event_calendar.php?accountid=5...

Excellent points - here are a couple more factors:

- Often reservoirs are filled via gravity from elevations that are higher. If the precipitation at those higher elevations is falling as snow, you have to wait for it to melt before seeing the benefits.

- When the ground is dry and the aquifers depleted, less of the rainfall will make it into the reservoirs. I'm from central PA and MOST of our water is actually stored in the natural aquifers (under my area of the state, it's water-fllled limestone caves). So to be fair to el Nino, you have to look at how the aquifers are responding to the rain.

- California would be an unpleasant place if four years of drought were reversed in a single year.

I remember hearing last year that we'd need something like 3-4 wet years in a row to counter the many years of drought.

This article is confusing level with flow rate. For Lake Shasta in particular, it looks like we're trending upward faster than the previous average.

-> The historical average reservoir storage level is the hard-to-see aqua in the background, and the thick blue line that stops around today’s date is the current storage level.

I'm really not sure if this is an appropriate criticism, but if you are trying to plot something like this and you don't like the color contrast because it's hard to see then change it. For me, the cyan-on-grey is tough to see.

He has lifted the graphs from here[1]. I'm not sure if the underlying data is available.

[1] http://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action...

Lake mead outside of California is also one of it's largest sources of water. http://mead.uslakes.info/level.asp

See also: "Insights for California water policy from computer modeling" (California Water Blog, February 9, 2012, by Elena M. Lopez)

http://californiawaterblog.com/2012/02/09/insights-for-calif...

I find the Lopez article to be a better read because it is detailed and level-headed.

The author talks about a recent "onslaught" of precipitation. Hardly. In Silicon Valley we've had a few mildly damp days, with sprinkles here and there, and a small handful of days with real rain during part of the day. Compared to some rainy years in the past, this year has been remarkably dry given it's supposedly an El Niño year. "Onslaught" it is not.

That's an interesting perspective. I would think it's the amount of precipitation at the major watersheds and reservoirs that would be indicative of an "onslaught", rather than what happens in Silicon Valley.

Silicon Valley lies alongside a large watershed with several reservoirs. Many people don't realize this. Hearing the name "Silicon Valley" makes one think of miles of tech buildings, but that's just part of it. I supposed "major" is a relative term though, so you're still right.

SV is pretty much in a rain shadow from SC mountains, so what happens there has little bearing on whether or not it's wet as a whole in CA. If you look at SF, then total precip is north of 100% of normal, and holy bejesus it's been raining in the SC mountains for example.

I can confirm. I live in Santa Cruz and commute to San Jose, the difference in rainfall has been striking. Santa Cruz has been pouring almost every day, San Jose has rained a few times, but stays mostly overcast and drizzles a bit.

What an odd mix of meaningful data with meaningless commentary about it.

yo im just happy about all the snow in tahoe, has not been like this since 2009-2010. Hopefully we get some good snow melt. The Alameda Creek also looks like it has good flow to it, have not seen that in a while, from this past summer of walking around in the dry bed.

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