State plans to order drought restrictions, but it doesn’t have good water data to do it

San Francisco Chronicle (tiered subscription) –

As California descends deeper into drought, state regulators are planning to do something they’ve done few times in modern history: order thousands of people, farms, and even cities and towns that hold historic water rights to stop drawing water from the rivers, lakes and ponds they rely on.  The problem, besides leaving several in a tough spot, is that the state doesn’t have an accurate tally of how much water is being pulled from its watersheds, nor who exactly is taking it. This lack of information makes it hard for regulators to determine which water rights holders to restrict, and how many.