California lawmakers on Tuesday advanced a bill that would put a on hold Gov. Jerry Brown’s $15 billion water plan unless it gets approval from voters.

The Bay Delta Conservation Plan would build massive, 30-mile-long twin tunnels underneath the Sacramento-San Joaquin Delta. Last year, the state released a 48,000-page environmental impact report on the project. Critics and environmentalists obect to the plan, stating that it would not create more water for the drought-stricken state.