Concrete Steps to Attack Climate Change Impacts (concrete - get it.. you will) #1

We need to address the IMPACTS climate change now, not debate its causes (people's mind's are set).
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As you might know, I don't think we can stop Climate Change.  It is too far along AND the world (not just Americans) are dependent on progress, which uses energy, which creates carbon over the short term.  Even if Americans and Europeans and Rich Asian / Latin American societies could afford to move to renewable sources, poor people would still use cheap, carbon heavy energy sources.
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So let's not argue if it is real, what are the concrete steps we can take to mitigate the effects?  Let's start with small steps.

LA River pre 1938

Well Los Angeles is taking one, one that is applicable to other cities in Mediterranean climates;
 rethink water management.  Where can this help?  Australia, Chile, Spain, Portugal, Italy, Greece, Turkey, Israel and others
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For years, the Los Angeles River would go through natural yearly cycles of flooding and drying up.  It is normal in an essentially a desert environment.  Deserts flash flood because the elevations are so step, and the bone dry land can't absorb the water quick enough.
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In 1938, a major flood hit LA via the LA River and, in fact, changed the course of the river (it used to exit via Ballonga Creek to the west of the city (where Tommy Lee Jones redirected the lava in Volcano).  After the flood, it exits at the Harbor, south of the cycle (about 30 miles down the coast, and past the Palos Verdes Peninsula).

LA River 1938 Flood

So the Army Corp of Engineers and the City Fathers devised a plan to line the river with concrete.  Which worked as designed.  It was designed to move flood waters as quickly and safely to the ocean as possible.  And although the flood waters have come close to the top of the river, it hasn't been breached since.  No floods and works as advertised.
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LA River 1940 - 2005 (you know it as Thunder Road from Grease)

But it is a huge waste of water.  The new method (which works) to to tear up the concrete floor of the river and plant some resistant trees, shrubs and add boulders.  The idea is to slow down the water and let it seep into the water table.  That water can later be pumped out.
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The concrete walls are still there to forestall 1938 style flooding.  And if there massive runoff some time, then the plants will have to be replanted - but it preserves as much water as possible.
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LA River near Griffith Park

Now, LA did NOT do it for Climate Change.  It is prettier and the homeowners set about this.  It is costlier to do and to maintain - but it will reduce spot warming (true - a very minor benefit) but be able to handled a new climate that has less precipitation as snow.
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Los Angeles (and all of California) depends on snow melt from the high mountains for water.  As the climate changes, that precipitation is coming as rain, not snow.  And so we have to find a way to capture that rain.  This is one way.
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This is what I mean when I say Climate Change is happening, we have to deal with it.
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The San Gabriel River (just to the East) has gone even farther.
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I am not sure you can see in the picture, but they divert all the water into temporary lakes / ponds where it can seap into the water table.  There are systems to divert a major flood into the main (concrete) river channel - but unless it is needed almost all water goes back into the water table.

The San Gabriel Holding Ponds adjacent to the 605 (the San Gabriel River Valley Freeway)