>Wouldn't this create a bit of water shortages downhill though? Like when you build a dam?
Great question! Dams themselves don't causes water shortages. It's the pumping of water from the dam to a separate watershed, or into highly evaporative irrigation systems (e.g. the Aral Sea and cotton).
Keyline design actually proposes building dams, but on a smaller scale than is typically seen and with no pumping between watersheds. Picture multiple redundant dams for every farm, each a few megalitre in size and a few thousand dollars to construct.
Many small dams wet up the entire landscape by slowing water down. Maybe this sounds obvious, but if water takes 10 times as long to reach the ocean then you have 10 times as much water to work with in the landscape.
Infiltration does the same. Subterranean water continues to flow downhill, but thousands of times more slowly. You can even recharge old spring lines in this way, benefiting the downhill hydrology directly.
>Sometimes we come up with solutions that work well in Sim City, but reality proves a bit more complicated.
They are looking into something similar in the UK to manage floodwaters, so that instead of funneling water fast and out, which massively increases erosion and sometimes overwhelms bridges down stream, you work out where you can let the water hang around in times of flood and make agreements with farmers to have flash flood basins.
Portland Oregon does something similar on a much smaller scale. To prevent the sewage system from being overwhelmed in periods of heavy rain, they've installed "swales" and stormwater planters [1] that redirect the water into the ground. I've walked around in the rain and the difference is remarkable--typical curb drains would be overflowing with water, while the drains near the swales and planters would be dry.
Great question! Dams themselves don't causes water shortages. It's the pumping of water from the dam to a separate watershed, or into highly evaporative irrigation systems (e.g. the Aral Sea and cotton).
Keyline design actually proposes building dams, but on a smaller scale than is typically seen and with no pumping between watersheds. Picture multiple redundant dams for every farm, each a few megalitre in size and a few thousand dollars to construct.
Many small dams wet up the entire landscape by slowing water down. Maybe this sounds obvious, but if water takes 10 times as long to reach the ocean then you have 10 times as much water to work with in the landscape.
Infiltration does the same. Subterranean water continues to flow downhill, but thousands of times more slowly. You can even recharge old spring lines in this way, benefiting the downhill hydrology directly.
>Sometimes we come up with solutions that work well in Sim City, but reality proves a bit more complicated.
On a wildly off-topic tangent, I just saw a fascinating talk in which Naomi Klein refers to this as "astronaut-eye environmentalism". https://www.youtube.com/watch?v=Jdaxehd0cF0#t=6m29s