Update on Hanson Floodplain Restoration Project – 4.3.19

The last six months have been busy ones for the Project team working to convert 360 acres of riverside gravel pits into productive floodplains. Russian Riverkeeper took over as the Hanson property caretaker in November 2018 and documented water levels and speeds of the River during the February flood. Our current priority for the Hanson Project is working with a team of consultants to complete the 30% design and screening for environmental issues. Last fall we helped the team of ecologists from HT Harvey to assess the habitat and plants on the property as well as overall ecological function. This work will help us see where the areas of high habitat value exist outside the mining footprint on the property so we can protect and preserve those areas. Currently geotechnical and groundwater studies and work are ongoing to help inform the engineering design and in February, Russian Riverkeeper staff teamed up with Jackson Family Wines (JFW) to cleanup trash from past flood events and remove non-native invasive Arrundo Donax (giant reed). JFW’s Kelli-Ann’s Vineyard borders the Hanson site to the east so it was a natural fit for their annual volunteer community workday.

During the February flood events, Riverkeeper staff captured information from the Hanson site to help inform the project’s design process. We were able to capture information on where water travels across the Hanson property as the river rises and falls. We learned that restoring the floodplains by eliminating the berms around the pits would help improve drainage in upstream and adjacent vineyards especially in spring when vines come out of dormancy.

While it has been 23 years since our last flood, this recent weather event is a reminder that Climate Change will increase temperatures, which will make future storms more extreme. This means droughts will be longer and hotter and floods will be bigger and more damaging. Currently our top priority at Riverkeeper is the Hanson Floodplain Restoration Project because it will help buffer us from these bigger floods and droughts. By restoring the floodplain that was eliminated due to mining we bring back more upstream flood storage and increase groundwater recharge.

5th District Supervisor Lynda Hopkins (whose district took most of the flood damage) mentioned Hanson as a solution to reduce the flooding impacts downstream in a March 2nd Press Democrat article