FLAGSTAFF, Ariz. (AP) — The Latest on the Colorado River drought plan (all times local):

1 p.m.

A powerful California water agency says it's disappointed an irrigation district is suing to block a multi-state plan to preserve Colorado River water.

The Imperial Irrigation District alleges the Metropolitan Water District violated an environmental law in pledging to contribute California's share of water under the drought contingency plan. Imperial is asking the Los Angeles County Superior Court to force Metropolitan into compliance.

Metropolitan general manager Jeff Kightlinger said Wednesday that water agencies in the seven Western states that rely on the river need to work together, not sue.

He says the drought plan will have no impact on a massive, briny lake southeast of Los Angeles. The lack of funding to address environmental concerns over the Salton Sea kept Imperial from joining the drought plan.

11:55 a.m.

A California irrigation district has filed a legal challenge to a plan designed to protect a water source that serves 40 million people in the U.S. West.

The drought contingency plan seeks to keep two Colorado River reservoirs from dropping so low they cannot deliver water or produce hydropower.

The Imperial Irrigation District didn't sign on to the multi-state plan over concerns about a massive, briny lake southeast of Los Angeles.

Imperial is alleging another powerful California water agency, the Metropolitan Water District, violated environmental laws in pledging to contribute California's share of water under the drought plan.

Imperial's petition filed in Los Angeles County Superior Court on Tuesday came the same day President Donald Trump approved the drought plan.

MWD did not immediately respond to a request for comment Wednesday.