I am responding to Stuart Smith’s letter “Accusations without evidence," (Jan. 19) which was a response to Mark Smithers’ letter: “Climate and environmental downside of vineyards."
Smith argues well in favor of critical thinking, facts and science. He says the river is “cleaner today than at any time in the past 60 years...” and quotes the California Regional Water Quality Control Board about its delisting of the Napa River as impaired because of nutrients.
Very well. However, Smith omits an important fact. The Water Board lists the Napa River and its tributaries as impaired because of sediment. I emailed the Board to verify whether or not this is still in effect. They responded: “The sediment impaired (status) remains in place.”
As to evidence of the cause of sedimentation, the “Napa River Sediment TMDL and Habitat Enhancement Plan, 2009” identifies channel incision and associated bank erosion as a cause.
The plan states: “More than half of all sediment…comes from roads, erosion of the bed and banks, vineyards and intensive historical grazing.”
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The Water Board has adopted the “General Permit for Vineyard Properties in the Napa River and Sonoma Creek Watersheds” as a means to work with Vineyard owners and regulate waste discharges from vineyard properties. It implements controls on sediment release.
Smith’s letter does describe the requirements of the General Permit but without naming it and without acknowledging the still-existing sedimentation impairment of the Napa River and its tributaries.