Watershed Restoration

Guidelines for a healthy watershed limit roads to 3 miles per square mile of forest. Large portions of the San Lorenzo watershed exceed that amount by four times.

The San Lorenzo River watershed has suffered abuse since the Gold Rush. All but 4% of Old Growth redwood forest was cut to supply lumber for growing populations and fuel for lime kilns. Extensive logging in the post WW II era, carried out by heavy equipment, filled the San Lorenzo and its tributaries with sediment, fouling habitat for native salmon.

Today, recovery of native fish habitat is impaired by sediment that continues to wash into creeks during storms from roads in the forest. Steelhead salmon that are spawning in streams need large size gravel beds to create their “redds” (nests). Fine sediment makes it difficult to create a redd and difficult for hatched salmon fry to get enough oxygen. According to the San Lorenzo River Watershed Management Plan 2001 Update, “Bed Sedimentation in the San Lorenzo River Watershed has not improved since 1979.”

A Metro Santa Cruz article, “Roads to Ruin”, reported, “Santa Cruz County environmental planner Dave Hope … echoes an opinion widely held among geologists, biologists and even foresters that disastrous erosion problems stem from an estimated hundreds of miles of both new and abandoned logging roads and illegally constructed roads that snake throughout Santa Cruz County.”1

Sediment is also a problem for human users. Muddy runoff following storms prevents the City of Santa Cruz from using the river as a water source. Because the City’s water treatment facility needs a water supply with low turbidity, when the water is muddy the City draws water from its reservoir, Loch Lomond.

The National Marine Fisheries Service guidelines for a healthy watershed limit roads to 3 miles of road for every square mile of forest. The Lompico and Lower Zayante sub-basins have 13 miles per sq mile. Ben Lomond sub-basin has 14 miles of road per square mile. And these statistics don’t count logging roads or roads that aren’t used for access.2 The San Lorenzo River and several tributaries continue to be listed as impaired for sediment, pathogens, and nitrates under the Clean Water Act. Runoff from septic tanks is a major factor causing the high levels of pathogens and nitrates.

The County cannot regulate timber harvesting because the state reserves that prerogative. But the County can inspect timber harvests to ensure compliance with Calif. Dept. of Forestry regulations. Timber harvesting in the watershed averaged 3137 acres per year in the 10 years from 1989-19983. The City of Santa Cruz owns forest land in the watersheds of Newell Creek and Zayante Creek. Until recently, the City logged this land. The City stopped logging its watershed property in response to concerns over sedimentation of creeks. Some groups are advocating further public purchase of riparian sections of the San Lorenzo watershed in order to prevent logging there.

Development has also impacted the watershed. The County’s San Lorenzo Watershed Management Plan (download pdf here) reports, “Growth also continued at a high rate in the City of Scotts Valley, with an 80% increase in developed parcels from the 1980 to 2000. High rates of development in the Scotts Valley area resulted in erosion of sandy areas, paving of groundwater recharge areas, and increased pumping of groundwater.”4

Until recently the County removed fallen wood from the San Lorenzo and its tributaries. Wood in the streams is an important contributor to juvenile salmonid habitat, creating pools that provide refuge from predators and directing water flows that scour sediment from the stream bed. Now the County’s policy is to encourage in-stream wood, assisting property owners in assessing potential hazards of wood in the streams before a permit is granted to remove the wood. But education is needed in order for property owners to change old habits.

The fiscal crisis of the state has dimmed prospects for watershed restoration. The County report continues,
“Stronger regulations were implemented to reduce erosion from new development, but many of the recommendations for funding and technical assistance to address existing chronic erosion sources were not fully implemented due to significant funding cutbacks in local and federal programs. Stream sedimentation has not improved substantially since adoption of the 1979 Plan. Chronic sediment contribution from public and private roads remains as a significant source of stream degradation.”5

SC Desal Alternatives notes that there exists a huge backlog of needed watershed restoration work at the same time that a large number of people in our community need employment. We believe that investment in watershed restoration should be a priority of our water agencies.

1 Kelly Luker, “Roads to Ruin”, Metro Santa Cruz, April 16, 1998
2 San Lorenzo Watershed Management Plan p 11
3 ibid p 12
4 ibid p 7
5 ibid, p 4

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