Near-record strength El Niño still on track to bring a wet California winter | Hacker News Reader

Near-record strength El Niño still on track to bring a wet California winter

weatherwest.com

56 pointsapsec11216 comments

I've always wondered how sensible is it to dig temporary holes/ditches that will store excess amounts of water and then later fill it back up once we're done with it. This is similar to how an empty swimming pool may be used to store excess rainfall. Perhaps the work put into it isn't worth the effort?

Is this not what reservoirs are?

Right. It is impractical to dig a ditch big enough to matter. That's why you damn up mountain canyons instead.

https://en.wikipedia.org/wiki/Groundwater_recharge

> Groundwater is recharged naturally by rain and snow melt and to a smaller extent by surface water (rivers and lakes).

This doesn't work when you've collapsed your aquifers through excess pumping.

http://news.nationalgeographic.com/news/2014/08/140819-groun...

India's arid areas appear to have some experience with 'check dams' for precisely this purpose - turning monsoonal wet seasons into year-round wellwater.

http://lawschool.unm.edu/nrj/volumes/48/3/03_agoramoorthy_in...

http://www.researchgate.net/publication/247773763_A_review_o...

http://www.iwmi.cgiar.org/Publications/CABI_Publications/CA_...

Digging ditches is much less cost-effective for this purpose than building small dams, though they seem to have also worked with those, ditches filled with rocks under a cover and used as a storage tank.

I think that's what Stepwells are all about.

https://en.wikipedia.org/wiki/Stepwell

https://www.youtube.com/watch?v=ilWbowNv5PI <- This is a huge stepwell, to give you an idea of why these can be so amazing.

It's very worth it. I can't find the link now, but there was a great article about traditional wier/retention pond building in Africa that both provided water but also helped recharge the local wells. The system had fallen into disrepair, and one local evangelized rebuilding the structures. It really took the entire community to rebuild and maintain, but improved the quality of life massively.

Meanwhile, Northern Europe has just seen one of the driest Octobers for a long while. Large areas has received less than five percent of normal precipitation. Stockholm has never had so little rain in October since measurements started back in 1786, beating a record from 1866.

Will be interesting to see if this continues into winter.

Does El Nino have an affect Europe?

Maybe a good time to buy wheat futures? Australia's east coast wheat crop is going to have a rough year or three.

Given the trend to wetter seasons in the south I wonder if anyone is thinking about increasing reservoir capacity there?

Here's one project that's starting:

http://www.latimes.com/local/california/la-me-stormwater-pla...

Enough rainwater falls on LA to provide for all of LA's water needs. Now almost all of this rain goes into the ocean.

That is awesome, thanks for that link.

Meanwhile, greatest environmental disaster of this century is underway in Indonesia. Heard of it?

http://www.theguardian.com/commentisfree/2015/oct/30/indones...

Meanwhile, greatest environmental disaster of this century is underway in Indonesia. 3 weeks more C02 has been released than annually in Germany & is currently releasing more C02 than the US economy. The flip side to this forecast in California. Heard of it?

http://www.theguardian.com/commentisfree/2015/oct/30/indones...

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