I think they're trying to point out how little effort is put into environmental restoration that would allow our environment to hold more water instead of having most of our rainwater wash out into sewers. Some of the loss in the environment's ability to hold water is due to large infrastructure projects in the first place. We are heavily draining the landscape and its causing us to lose critical topsoils (some of which took thousands of years to make).

Compared to 200 years ago, water moves around much more but California overall has MUCH less water.