Earlier quoted context omitted.
But expensive to transport relative to its value.
Expensive to transport in some cases but not others. In the scenario I was responding to it is quite cheap to transport water form the mountains past the farms to the cities because water flows down hill. Water that is not used in farming is available for use in the cities.
I first heard the word, "fungible" from Dick Cheney of all people. It was in the context of Canada selling Oil through its ports to the Chinese instead of building a pipeline down to the United States, and his was response was, "That's fine. Oil is fungible." - I.E. Canada Selling Oil to the Chinese would be just as beneficial to the United States, as Canada Selling Oil to the United States, because the oil that we sold to the Chinese, would free up oil from other sellers, which would then go to the United States. All that mattered was that oil was produced and placed on the "Global" Market.
Water, on the other hand, is expensive to distribute compared to its generation, so water from Crystal Springs Reservoir, all 70,000,000 m^3 of it, really only has value for residential use. There is no agriculture competition for it.
In the case of the Sierra Nevada - I think we both concur that water is useful for both residential or agricultural use.