Zone 7 Water Agency’s failed flood control system needs a total revamp from the ground up, according to a consultant hired by the agency.

The system can’t be saved by adding touches here and there. It will need a whole new rethinking, and will be expensive, said Eric Nagy, a principal with the firm Larsen, Wurzel & Associates in Sacramento.

Nagy delivered his report at the board’s Sept. 2 virtual special meeting. No formal board vote was taken, because the item was placed on the agenda for discussion only, not action.

However, General Manager Valerie Pryor asked for the board’s consensus about a direction the agency could take toward developing a superior plan to cover flood control the next 50 years.

Zone 7 updates its strategic plan every five years. The board’s consensus now will inserts the reconstruction of flood control as part of that plan.

Zone 7 wants to plan with a maximum number of stakeholders and agencies that might want to work together on building trails. Zone 7 has cooperated in the past about trails, but has made it clear it is not interested in providing them itself.

Nagy cited a list of issues to address, including climate change’s impact on the timing and amount of rain that falls locally and in reservoirs that affect the Valley. When the current Stream Management Master Plan (SMMP) was adopted in 2006, climate change was not a discussion topic.

Now, the federal government studies new data from coastal and inland storms to get a better idea of how changes in storms are affecting climate and the costs of dealing with flooding. The cost of these storms add up to the greatest single amount by far spent on weather impact in the United States, said Nagy.

Nagy went on to say that on the West Coast, climate change shifted the airborne rivers of water in the upper atmosphere, and created new impacts on various California locales.

Climate changes can have an impact on the snowpack, evaporation rate, precipitation rate, along with surface runoff and stream flow.

Another issue for future consideration involves a better approach to flood channel coordination. Originally, all of the channels were supposed to be one seamless system, but the game plan changed.

At first, in the 1950s to 1970s, the county followed the direction of the Army Corps of Engineers and used concrete-lined channels, intending to move the water to the Bay as fast as possible.

Then, there was a change in philosophy, a move to a natural look, which used dirt, trees and other habitat elements to slow the streams and beautify and protect them. The two approaches have not worked so well together, said Nagy.

A special problem of Zone 7 flood control failure has been the quality of soil in the Valley’s West End.

In the West Valley, soil conditions over the past couple of years became so bad that 121 stream banks collapsed, many of them along the Arroyo de La Laguna near Castlewood, which will cost Zone 7 some $20 million to repair.

In one 2017 storm, which drew lawsuits from property owners, homeowners lost significant chunks of their properties. In one backyard, the stream-side cliff collapsed to within a few feet short of a swimming pool.

Nagy said that, in view of the need for Zone 7 to get many stakeholders involved in the process, “I don’t expect it to be a quick plan to develop.”

Nagy did not name any cost figures. Costs will depend on input from local cities and the county on how the plan will affect future development.

Zone 7 Board Vice President Angela Ramirez Holmes said that since Zone 7 has no zoning power of its own, dialogue with cities and the county will be important.

Other potential stakeholders include the state and federal agencies that issue permits for flood control projects to meet environmental standards, and jurisdictions, such as park districts, that might want to create trails near Zone 7 arroyos.

Zone 7 has made it clear that it does not want to go into the recreation business, but has supported trails that park districts are willing to create and maintain.

Director Sandy Figuers brought up his own financial estimate, based on the needs and the past experiences of trying to convince the public to approve bonds.

The first bond issue for Zone 7 won voter approval, because it raised money to build water facilities, so that developers could build here to satisfy a house-hunting public, said Figuers.

Those efforts took place after the county created Zone 7 in 1957. But Figuers noted that when the agency went out to raise bonds for flood control, none of the three measures passed.

Figuers named his own estimate for a future plan — from $500 million to $1 billion — and suggested Zone 7 could pick a financial goal and shape the plan to fit the budget.

But the other six directors favored creating the plan first, determining its most important components, and working on financing those.

On finances, Nagy said that one topic that should be explored would involve turning the operations and financing of the flood system over to the county.