Driving down the East Cypress Corridor in Oakley, John Cain waves a hand at the new subdivisions and construction sites out the driver's side window.

"As recently as three years ago, none of this development was here," says Cain, a restoration ecologist at the Natural Heritage Institute.

At a time when policymakers are trying to determine what the Delta's future will hold, development is eliminating choices.

The Delta Protection Commission, which was created in 1992 to protect Delta agricultural land, maintains an incomplete list of proposed development: 3,500 houses and 1.2 million square feet of commercial space in Oakley's East Cypress Corridor; 2,000 acres for an unknown number of houses in Lathrop and more than 1,000 in Isleton; and more.

"Urbanization is an irreversible course of action that commits us to all kinds of obligations in the future _ which will be quite expensive, both financially and on quality of life," Cain said. "It's pretty clear that urbanization in the Delta is affecting everything CalFed is trying to do."

Jeff Mount, a UC Davis geologist, said the suburbanization of the Delta will mean fewer response options in a big flood.

Emergency response managers will be forced to save lives and property on developed islands and will not be able to let them flood to relieve the pressure on other levees. That could lead to a domino effect that jeopardizes a larger portion of the Delta and the water supply it provides for two-thirds of California residents.

Mount was a member of the state Reclamation Board until he was fired by Gov. Arnold Schwarzenegger in September, along with the rest of the board, which was becoming more outspoken about development and flood risk in the Delta.

But Mount said CalFed, the program set up to manage the myriad interests in the Delta, should have addressed the issue, too.

"CalFed never tackled this because it was political poison," said Mount.

Lawrence Kolb, assistant executive officer of the San Francisco Bay Regional Water Quality Control Board, said the state needs a new agency akin to the Bay Conservation and Development Commission, which was created in 1965 to stop cities and developers from filling the San Francisco Bay.

"I think we need the state Legislature to protect the Delta from unwise development in flood-prone areas," Kolb said. "And I think that the cities will never do that on their own, just like they never have stopped filling the Bay."