Mayor Denis Law has proclaimed a state of emergency so that the city can prepare now for flooding of the Green River if Howard Hanson Dam’s storage capacity is severely reduced.

Technically, this is a pre-incident declaration that gives city departments the required authorization to prepare for, stabilize and control any emergency or disaster situation, according to city officials.

The Renton City Council has approved the declaration.

“Renton is working hard to plan for and prepare for potential flooding on the Green River in the event of severe weather,” said Law.

But, he points out that businesses and residents need to prepare, too, by reviewing flood insurance, signing up for CodeRed, city’s new emergency notification system, and establishing an emergency plan.

Local governments in South King County and King County are coordinating efforts to respond to what could be major flooding of the Green River this winter.

The right abutment of Howard Hanson Dam, a flood-control project that made possible the commercial and industrial development of the Green River Valley starting in the 1960s, is leaking after it was damaged in last January’s massive storms.

Because of the damage, its operators, the U.S. Army Corps of Engineers, have determined the dam will be unable to hold back as much water in storage during heavy rains, increasing the change of flooding.

The situation creates a higher possibility of flooding in areas of Renton in the river’s floodplain, which in Renton is generally from Highway 167 west to the Green River and its southern boundary north to the Burlington Northern railway corridor, according to city officials.

City officials stress that it would take a catastrophic event for the flood waters to reach downtown Renton and significant flooding may not occur.

Last week at a briefing, the King County Council was told that floodwaters in a worst-case scenario could reach up to 10 feet at the county’s elections headquarters on Southwest Grady Way in Renton.

Renton officials say lower flood levels are much more likely. But even a few feet of standing water would affect transportation routes, water may enter some buildings and operation of King County’s wastewater treatment plant in Renton could be affected.

The city is already in the planning stages for any emergency, including applying for a grant from the Corps of Engineers to help pay for those efforts. For example, the city wants to buy flood barriers that will be installed prior to flood season.

The city is also coordinating with King County to obtain large diesel powered pumps. These pumps would be temporarily installed at the Black River Pump Station to try to keep water levels in Springbrook Creek below flood stage.

The other jurisdictions that have levees on the Green River levees are also planning similar flood mitigation measures.