Flooding on Green Valley Road
In the past, Gold Ridge RCD has worked with the community to identify a solution to the chronic flooding of Green Valley Creek across Green Valley Road just outside Graton, CA. Local organizations have conducted and presented studies of the causes of flooding and potential short- and long-term solutions. Gold Ridge RCD did not fund or manage flood mitigation projects. Instead, it has played a role in facilitating the research and development of mitigation solutions.
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Recent Community Updates
The following is a message from the County's Transportation and Public Works Department written in December 2017:
Hello Green Valley Neighbors,
This is a general update on Green Valley Road and Creek. If you've expressed interest in staying up to date with the flooding issues on Green Valley Road we've added your email to this GovDelivery list. If you know someone who may like to sign up they can do so here.
Actions Taken
Last winter, the Sonoma County Water Agency removed sediment from Green Valley Creek near where it crosses Green Valley Road. This temporary solution is designed to reduce the duration of flood events, while a much larger project is needed to solve the reoccurring flooding.
This summer, Transportation and Public Works (TPW) resurfaced the road and reinforced the slope protection on the east side of the road.
A multi-agency group led by Gold Ridge Resource Conservation District worked for several years on a long-term plan to address the flooding of the creek and Green Valley Road. This long time frame is due to the complexity of finding a solution and working to resolve this issue within current funding and permitting constraints. Moving forward, the management of this project has transitioned to the Water Agency, who will coordinate with TPW.
In the Works
Next summer the Water Agency plans to apply for permits and again clear out the sediment that quickly accumulates where the creek crosses Green Valley Road.
As neither the Water Agency nor TPW have the jurisdiction or funding to maintain Green Valley Creek, the Water Agency is applying for funding for a long-term project that protects the road and meets environmental standards, with support from TPW. The Water Agency and TPW submitted a pre-application to determine if further work on Green Valley is eligible for Federal Hazard Mitigation grant funds. We have been invited to apply for funds, and are currently working on an application for this highly competitive grant funding.
The grant application is due November first, and we expect that we will hear if we’ve been awarded funds in early 2018. Ideally, the grant would fund project design, permitting and construction. If funded, construction would be a few years away.
This Winter and Communications
Throughout the winter you can stay up to date with road closures here. TPW recognizes that this is a crucial route for the area, and only plans to use immovable barricades (K-Rail) on the road if it appears that the pavement is damaged and would be a safety hazard to drivers, or at the request of emergency responders reacting to unsafe conditions.
In the extremely unfortunate circumstance that immovable barricades are required, TPW will notify this Green Valley email list. As a part of the grant application we will evaluate the feasibility of a webcam for the road, however because of the timing of the grant it will not be available this winter. TPW will send an update to the Green Valley email list when we hear back from the grant funding agencies in 2018. We will also notify the email list when substantial work is taking place, such as the Water Agency sediment removal plans for the summer of 2018.
Many thanks,
Transportation and Public Works
2300 County Center Drive
Suite B 100
Santa Rosa, CA 95403
Past Community Updates
March 10, 2017 Update: Green Valley Road has one lane open. Repairs on the other lane will start once the pavement has dried out.
March 10, 2017 Update: The creek excavation to restore capacity in Green Valley Creek went smoothly and was completed today. Green Valley Creek is flowing in the channel and no longer flowing across the road. County Department of Transportation and Public Works (DTPW) staff will be assessing the repairs needed on the road surface this afternoon (there is mud on the road currently and impact from the heavy equipment) and will make a determination about when the road can be re-opened to one-lane. Further repairs will need to be made to open to 2 lanes and we will let you know when we hear an update on that work.
Status of the road closure can be found at: http://roadconditions.sonoma-county.org/
We want to thank the Sonoma County Water Agency crews for all of their hard work, as well as express our gratitude to Maddocks Construction, Sanchietti Farming, Dutton Ranch and Bohan and Canelis for all of their help through this project. We will send out an update on the road repair schedule and any associated closures as soon as we have more information.
March 8, 2017 Update: Work got underway in Green Valley Creek adjacent to Green Valley Road on Monday. Sonoma County Water Agency crews have been busy expanding the capacity of the stream channel. As soon as the excavation is complete, Green Valley Creek will be able to resume flowing into the channel. Once the stream is no longer flowing across the road, County Transportation and Public Works staff will be able to assess the repairs needed on the road surface. The goal is to open at least one lane of Green Valley Road as soon as possible and we’ll keep you updated as soon as we have more information on when this will occur.
Press Release Emergency Green Valley Road Project Slated to Begin Monday - Sonoma County Water Agency, Mar 2, 2017
Press Release coverage of the Feb 10, 2017 Emergency Public Meeting - Sonoma County Water Agency, Feb 14, 2017
Initial Press Release announcing the Feb 10, 2017 Emergency Public Meeting - Sonoma County Water Agency, Feb 9, 2017
Emergency Public Meeting - February 10, 2017
An urgent meeting regarding emergency actions to address the flooding of Green Valley Creek at Green Valley Road (aka the “S curve”) was held Friday, February 10, 2017 at 4:00 pm at the Sanchietti barn, 10076 Green Valley Road, at the corner of Sullivan Road. Link to the Feb 10, 2017 Meeting Minutes
Public Meeting - November 17, 2016
A public meeting was held on November 17th, 5:30-6:45pm at the Oak Grove Elementary School Gymnasium, 8760 Bower St., Sebastopol, CA. This meeting was a follow up to our first public meeting on October 14, 2015, and an opportunity to hear about the progress made since we last met.
Links to Presentation Files:
Introduction by Gold Ridge RCD
Flood Zones Map, prepared by Sonoma County Water Agency
Flooding at Green Valley Road and Analysis of Mitigation Alternatives, presented by O'Connor Environmental, Inc.
Videos of Green Valley Creek Flooding on Green Valley Road
Information on Green Valley Road Flooding and Efforts to Mitigate
All titles are links to the documents.
Summary of Mitigation Alternatives for Flooding at Green Valley Road, 2016: This document summarizes four project alternatives (or options), from which a preferred alternative was selected. We will discuss these options at the November 17 meeting.
Matrix of Mitigation Alternatives for Flooding at Green Valley Road, 2016 : A quick reference sheet that abbreviates the alternatives (or options) outlined in the “Summary of Mitigation Alternatives for Flooding at Green Valley Road, 2016” (above).
Summary of Analysis of Flooding at Green Valley Road and Mitigation Alternatives, 2015: A previous version of and precursor to the “Summary of Mitigation Alternatives for Flooding at Green Valley Road, 2016” (above), this document includes a number of previously considered project alternatives, most of which were not pursued because they were either ineffective or not feasible.
Sediment Source Assessment for Upper Green Valley Creek, 2014: A separate but related study on the sources and rates of erosion and sedimentation in the Green Valley Creek watershed.
Green Valley Creek /Dutch Bill Creek Watersheds Update Report, 2015: This document summarizes the results of a hydrologic study of the Green Valley Creek watershed. It is more focused on low-flow conditions.
Green Valley Road Flooding Public Meeting flyer, 2015: Flier for the community meeting held last year.
Learn More
You can learn more about Green Valley Creek and the natural resource conservation efforts being made there by visiting its watershed page on the Gold Ridge RCD website.
If you would like to receive email updates regarding Green Valley Road flooding, use this link to to sign up to the County of Sonoma Electronic Subscription Service.