Dear Councilmembers Carnacchi, Hinton, Glade Gurney, Glass, and Slayter

March 5, 2019

  Dear Councilmembers Carnacchi, Hinton, Glade Gurney, Glass, and Slayter

  The Barlow marketplace was developed on an area that in 2005 had been proposed for mixed uses under the Northeast Area Plan (NEAP). That plan included housing elevated above flood level, with underground garages.  All the pros supported the idea, including professional planner, Lois Fischer, whose delightful presentation about blending town edges with countryside, lacked ANY reference to the site’s well demonstrated flood potential.

  Today I can only imagine the losses that the current flood would have imposed on unwary merchants and townies who understand little or nothing about the function of a floodplain—particularly that they form from repeated flooding, and are there to absorb the inevitable future floods.

  As a geoscience professional, I was one who warned against building out the NEAP on the Laguna floodplain. Sadly, I lacked deep enough

SF Gate image from Russian River flooding.

understanding of how little laypersons understood of the full hazard from building on a flood plain.

  Public opposition defeated NEAP, and public meetings about the proper use of the area proposed a movable market with parking areas for shoppers, as a much better idea.

The Barlow was not conceived as a movable market, however. Concerned citizens still worried about flooding, but the owner/developer seemed to be aware of the flood potential and to have protective solutions for tenants. Members of the public spoke against building on top of Zimpher Creek’s channel, but were not heard. 

  Until this flood, I had no idea that proposed flood protections for a winery had included “sump pumps” for a building at flood level in a floodplain. I would have spoken out against that concept; it’s complete nonsense! A stream or river or drain channel (such as the Laguna channel) is always the lowest level toward which water can flow.  Once the channel overfills and spills onto the floodplain (the Laguna itself), there is no further ability to pump water away from a flooded road or building.

  This is a hard lesson, and one that needs to be passed on from current Council members to future ones. Lives and livelihoods can depend on it.

  Perhaps its time for the City of Sebastopol to get more familiar with the behavior of water and pass that on to the citizenry. In my opinion, recovery for The Barlow should NOW include daylighting Zimpher Creek.  Along with the salute to the flag, perhaps the Council should repeat the flood zone formula: 

“ ‘100-year flood zone’ means that the flood-prone area can expect one flood-causing storm in 100 years.  If the area has 4 flood-causing storms per 100 years, it’s a 25-year flood zone.”

  Jane Nielson, Ph.D. Geologist