Forget the Freddy Krueger mask. If you want scary this Halloween, just take a look at what’s happening at the state Capitol.

Late last week, a bill was unveiled that would completely overhaul the state’s water delivery system — mandating conservation, setting up a new bureaucracy and paving the way for a canal to be built around the Sacramento-San Joaquin Delta.

But the bogeyman is not that the proposal is making the rounds. It’s that it’s not really making the rounds.

At least according to someone who knows how these things work — she is, after all, a member of the Legislature — the process that brought about “the most significant water policy bill in decades” has so far been a cloak-and-dagger enterprise.

“It’s been very secretive,” said state Sen. Lois Wolk, a Democrat who represents Tracy in addition to vast swaths of the Delta. “I’ve never seen it this bad.”

When I talked to her this week, Wolk was referring to the closed-door negotiations in Sacramento that led to the bill by Senate President Pro Tem Darrel Steinberg, a Democrat from Sacramento.

So far, Wolk said, the give-and-take leading to one of the most important pieces of legislation in California’s modern history has been directed by a small group of stakeholders out of the public eye.

Most notable of those vested interests are the Westlands Water District, which supplies the thirsty west side of Kern and Fresno counties, and the Metropolitan Water District, which serves a collection of counties and cities in Southern California.

Both are voracious consumers of Delta agua. Both have considerable stakes in ensuring a stable and high-quality water supply for the folks they service — the former mostly farmers, the latter largely suburbanites.

Notably excluded from much of the discussion has been the five-county region including San Joaquin County that just happens to be home to the Delta.

According to Wolk, those who stand to lose the most in this game — from a restructuring of the state’s 150-year-old water rights system or from a peripheral canal shipping wet stuff around their homes and farms — have so far been on the outside looking in.

This is not reassuring for our region, considering Steinberg’s proposal could open the door for the dreaded peripheral canal by setting up a “Delta Stewardship Council,” a non-elected committee that would have vast discretion to govern California’s water.

Some environmentalists say that the bill doesn’t give carte-blanche for a canal, that it would still have to jump considerable hurdles. The director of the state’s Department of Water Resources, meanwhile, claims that the state already has authority to approve a canal’s construction.

But giving canal authority to an appointed council could give such a project more political legitimacy, not to mention a better chance of standing up to the inevitable legal challenges.

So excuse me for being cynical when supporters of this plan say it’s not a water grab. Because that’s sure what it looks like.

Sensing this, Wolk and Assemblywoman Alyson Huber floated a bill Friday that would keep the yea or nay on a canal under the Legislature’s purview.

It’s a clear shot across the bow of anyone who might be trying to fast-track a peripheral canal.

Wolk’s gambit might pass, or it might not. At the very least, it’s a signal that more local input is needed.

For one thing, doing so could ease the concerns of Delta denizens. It could also result in a better final product.

Perhaps a final product that keeps the Steinberg bill’s laudable conservation goals — cutting urban use 20 percent by 2020, for instance — but ditches the problem-fraught canal, a proposal that could hurt Delta farmers and ocean fishermen while burdening consumers with an upper-end cost estimate of $54 billion.

If nothing else, widening the table could convince those running this show that a canal-based plan won’t change the real cause of California’s water house of horrors:

Namely, that the Delta is not an unlimited resource.

The pumps outside Tracy can throttle up even during dry years, more dams can be built, more water can be siphoned to farm permanent crops in a grassland desert. Screw the smelt and drain the rivers. None of that will turn a shallow estuary into the deepest of drinking bowls.

The Delta already supplies two-thirds of the state’s population with water and irrigates millions of acres of farmland. Expecting it to deliver even more can’t be considered realistic.

But that type of thinking might well prevail if the conversation at the Capitol isn’t opened up. In fact, it might prevail anyway.

Talk about scary.

• Share your thoughts with columnist and associate editor Jon Mendelson at jmendelson@tracypress.com.