Three agencies are urging California’s top water regulators to approve an agreement that would commit the state to following through on its pledges at the Salton Sea, even as state funding for the shrinking lake remains an open question. The State Water Resources Control Board met Thursday to hear comments on the proposed agreement, which sets targets for state agencies tasked with building thousands of acres of ponds, wetlands and other dust-control projects around the lake over the next 10 years.