They showed this chart at the Water Plan meeting last week. I like it because it shows the different ways to address the gap between what we’ve got and what we want to have. You can move the purple demand line down (with water conservation, by price increases, by irrigating less land), or you can move the bouncy green line up (by conjunctive use, reservoir re-operation, or meadow restoration). The problem isn’t that mysterious. People have different guesses about which approaches have lots of leverage*, and they feel strong emotions about protecting the location of the purple line or embiggening the green line. What would be really great would be a chart that flips the yellow-orange line on its side, and puts cost on the y-axis. Then we should see the costs of lowering the demand line, raising the managed supply squiggle and experiencing shortfall all next to each other. But I don’t think anyone knows those cost numbers.
Couple more thoughts on that graph:
It shows the demand line rising over time; mostly from population increase, I suppose. But I don’t think there was ever a time when people thought they had enough water. They always felt like there wasn’t enough water, even when the population here was very small.
The squiggly green line should be capped at some max capacity, shouldn’t it?
Love, love, love that it shows annual runoff decreasing. Yep, that’s right. It has already started. I wonder if the green squiggly line shouldn’t be even closer to the bottom of the runoff line in the future if it is going to be harder to catch and store rainfall than it has been to catch slow snowmelt.
*My personal guess? I think urban conservation has relatively high yields (for providing additional water to cities), then the results drop off very quickly. Oh! Groundwater re-charge is pretty powerful too. I don’t think new dams get us much yield, which is why I don’t pay a lot of attention to them. I don’t think that agricultural water conservation gets at a ton of new water, because water is re-used in the ag valleys. Frankly, after water conservation and storing water underground, I think the next source of water comes from retiring ag lands. If you don’t like that, you should go back to thinking about moving the purple line down.