Blog note: this article references a 2015-16 grand jury report.
New flood protection strategies could shield 135 homes along Milton Road from levee-punishing storm surges and predicted sea level rise, but they come with a price.
Focusing on planning and preparation could cost $3.5 million. Building flood walls could cost $38 million to $79 million, according to a report done for the Napa River Reclamation District and Napa County Flood Control and Water Conservation District.
Residents of the small Edgerly Island and Ingersoll Tract community along the Napa River must weigh embarking on a multiyear journey of seeking grants and likely contributing from their own pockets.
“This is only a study,” Milton Road resident Devra Dallman said.
“It’s only a beginning. No decisions have been made.”
Her husband Mark Dallman observed that flood control projects in the city of Napa took several decades to achieve.
Richard Thomasser of the Flood Control District said the small community faces flood threats about every 10 years. The problem comes during windy storm surges when the tide is high.
Predicted sea level rise is a longer-range issue. Thomasser said a rise of three feet by the end of the century would change flooding threats along Milton Road from a 10-year inconvenience to a daily struggle.
Resident Jay Gardner said some people might wonder why anyone wants to live in a place that seems to be so susceptible to flooding. But Edgerly Island hasn’t flooded since 1983, he said. The Ingersoll Tract has had some flooding since then.
“It’s actually a great place to live. And we all love it,” he said.
The Flood Control District Board of Directors on Tuesday accepted the study done by ESA consultants. The Napa River Reclamation District, which serves the Milton Road community, is to consider accepting the study on Oct. 4.
In addition, the Napa River Reclamation District is holding a community meeting on the study at 9 a.m. Saturday, Sept. 22 at the Edgerly Island Volunteer Fire Station, 1598 Milton Rd.
Milton Road runs through the remote south county, with the Napa River to the east and wetlands to the west. Homes on Edgerly Island and the Ingersoll Tract stretch along the road for about one and a half miles, forming a linear community.
A levee stands in backyards between homes and docks in the Napa River. Homeowners own the levee section on their land, leading to a patchwork maintenance approach that concerned the 2015-16 grand jury.
This levee is a testament to individuality rather than uniformity. One section might be topped by a gazebo, another by ivy, another by bare dirt. Only a single section has to fail to cause a flood.
“The homes on Milton Road are no longer the fishing shacks of yesteryear,” Devra Dallman said. “There are Milton Road homes valued at over a million dollars each and there are properties valued at over $2 million. But we are only as strong as the weakest link.”
More might be at stake than keeping a remote community high-and-dry. The grand jury was concerned that Napa County taxpayers could end up paying for damages if a catastrophic flood took place.
Thomasser said improving the levee to engineering standards is infeasible, given it would have to be several feet wider and would extend into the river. That led to the search for other solutions.
ESA suggested three possibilities to avoid a repeat of floods in such years as 1983, plus close calls during other big rain years.
The $79.3 million option creates a steel sheet flood wall along the Napa River at an initial height of 12.5 feet, with the potential to raise it to 15.5 feet to adapt to sea level rise. Flood walls would also be built along levees to the west that protect state-owned wetlands and a Flood Control District dredge disposal area.
The $38.3 million option is similar, but would create a 12.5-foot-high vinyl sheet pile flood wall that could not easily be raised to adapt to sea level rise. The levees to the west would be strengthened.
Both of these recommendations would hinge on the Napa River Reclamation District securing right-of-way easements from the homeowners.
Finally, the $3.5 million option focuses not on flood walls, but community preparedness and planning. Homeowners could elevate their homes. A part-time levee coordinator would help homeowners with levee maintenance. Sewer and water systems would be protected from floods.
What role the Flood Control District might play in helping the Milton Road community with the flood improvement steps remains to be seen. The district and Napa River Reclamation District split the $150,000 cost for the ESA study.
Napa County Board of Supervisors Chairman Brad Wagenknecht said the partnership can continue, but the Napa River Reclamation District will have to pay for part of the projects.
“If the community is working to try to take care of this, we will be there as a partner,” Wagenknecht said. “If the community says, ‘Thanks for that report’ and walks away, that’s not a partnership.”
September 22, 2018
Napa Valley Register
By Barry Eberling
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