Gov. Doug Ducey’s office is pushing a series of controversial proposals to overhaul state water management. One reason is to assure investors that Arizona has enough water for future economic development.

But water agencies are warring over how to make sure there’s enough water for long-term growth, and whether that means saying “no” to some short-term uses.

At issue is what one official calls the Colorado River’s “last supply.” That’s river water that no user with contracts to buy it — meaning cities, tribes, tribes and private water companies — wants in a given year.

Arizona’s water users and agencies are at odds over whether to leave that leftover water in Lake Mead or continue to allow some of it to supply suburban subdivisions, among other uses.

That issue is one of more than a dozen topics now being discussed — in private — by committees and work groups appointed by the governor, in order to “get the state’s act together” on water.

The proposals have split officials of the Central Arizona Project and the Arizona Department of Water Resources and their supporters into competing camps.

In an interview, Ducey’s chief of staff Kirk Adams made it clear that growth is a key factor driving these measures.

With the state’s economy, battered by the 2008 financial crisis and real estate bust, now rebounding, “the governor feels we need to be prepared for the growth,” Adams said.

When Adams meets with CEOs and other corporate decisionmakers considering investing in Arizona, water is consistently mentioned though it’s not at the top of their priority list, he said.