California is on the cusp of crucial decisions about its water future. Plans for new reservoirs and canals are gaining traction, pushed by interests that have the most to lose from court decisions and possible droughts.

Before the state plunges feet-first into a new generation of water works, though, it must recognize the limits of its hydrological heart – the Sacramento-San Joaquin Delta.

For far too long, California has treated the Delta and its vast watershed as a resource to be tapped and exploited.

Excessive pumping and diversions, from all parts of the vast watershed, have hurt fish and other wildlife. Excessive conversion of wetlands has turned the Delta into a mono-culture of sinking islands, vulnerable to floods and earthquakes. Excessive pollution has made the Delta a filthy place to draw drinking water.

There's no need to demonize past acts. Water agencies built water pumps, farmers converted wetlands and cities built sewage plants long before anyone recognized the Delta as a fragile ecosystem – our version of the Everglades.

But we know better now – or at least we should. As The Bee's Matt Weiser wrote in a special report on Sunday, "Recent events have revealed the truth: California is reaching the limit of its water supplies, and the economy and environment are suffering for it."

How can we judge if California is taking more water from the Delta and its watershed than they can handle? Consider the evidence: Smelt are at the brink of extinction. Other species, such as salmon, are in serious peril. Federal courts are using the hammer of the Endangered Species Act to deliver a blunt message about the entire ecosystem.

Dry years, when cities and farms suck more from the Delta than they do during more rainy times, are especially tough for these species. During wet years, 87 percent of the water entering the Delta makes it out to the San Francisco Bay. During dry years, the figure drops to 51 percent.

If California is to have any hope of restoring the Delta and avoiding clashes with federal judges, it must develop a water plan that reduces its dependence on this estuary and strives for greater reliability.

What would this plan look like? To begin with, it must be grounded in reality. Water contracts based on dated premises must be renegotiated, and efficiency should be the law of the land. Each region of the state – including Sacramento and the San Joaquin Valley – must find ways to reduce what it takes from the Delta and its watershed. And environmental groups must recognize that not every species will be restored to its population predating the Gold Rush.

Once all the shareholders have agreed to sacrifice, discussions over a canal – or some other option for the Delta – will go more smoothly. Without such a commitment, it's hard to imagine that environmental advocates and Northern Californians would agree to a canal that would be the vehicle for increased exports.

While this page won't render judgment on a canal until a specific project has been proposed, the status quo is clearly unsustainable. A canal holds the potential of reducing environmental conflicts and allowing the state to siphon off big flows during peak years, while safeguarding the state against natural disasters. But any canal project must be premised on a recognition of limits. Promising everything to everyone is how the Delta ended up in its current mess.