Lake Sherwood
Aquatic, Marsh, and Riparian Willow /
Oak Habitat Creation and Enhancement
– Ventura County
Project Objectives: To fully mitigate for impacts to 2.0 acres of aquatic (lake/shoreline), 0.5 acres of riparian, and 0.1 acres of marsh habitat through onsite creation and enhancement.
Services provided: Envicom Corporation provides a full spectrum of services to Sherwood Development Company, ranging from the preparation of tiered-MND’s, Section 404, 401, 2081, and 1603 permitting, biological resources surveys and inventory of over 2,000 acres, and salvaging and restoration of endangered plant species. This included the development of numerous biological resource protection and management plans, the salvage and propagation of native plant materials, weed eradication, construction monitoring, site preparation and ongoing services, as per the requirements specified in project permits and mitigation plans (Weed Abatement Plan, Oak Woodland Preservation Plan, Sensitive Wildlife Species Relocation Plan, Lyon’s Pentachaeta Management Plan, and others).
Restoration and Enhancement Plan: Our first step, in close coordination with the project engineer Pacific Coast Civil, was to avoid to the maximum extent feasible all jurisdictional and sensitive resources through careful planning. This was accomplished by an understanding of the exact location of the resources through rigorous mapping, which was imported by the engineer into their CAD system, and by the engineers’ willingness to examine alternative, creative designs. We conducted a complete analysis of the existing plant communities that would be impacted and developed a habitat profile for each site. Upon discussion with the agencies, it was determined that the addition of sycamore and oak trees to the riparian willow creation site would be appropriate and enhance the wildlife values of the habitat. We conducted surveys of the Sherwood property to find an available and suitable site. On the south shore of the lake, we found a relatively flat area surrounded by water on two sides. Using the average lake elevation, the engineer calculated the correct land elevations using our specifications for plant moisture/saturation requirements. By reducing the surface elevation by 8-6 feet, the groundwater level would be within 2-4 feet of the top, enough to support willows, and the shoreline flows would fluctuate with the rise and fall of the lake’s elevation creating an environment for a marsh plant community (no cattails were recommended in planting palette as they would naturally occur). The planting plan was prepared by our Principal Biologist and Native Plant Horticulturist, which the agencies approved. The plan included creation of Freshwater marsh habitat within small pockets of the created site and enhancement of both the preserved floodplain freshwater rush-dominated marsh and of the goldenrod/willow marsh. This included development of plant palettes, planting scheme, irrigation requirements, 90-day and long-term maintenance standards, and monitoring and success criteria.
Our staff provided specific plant palettes for hydroseeding on slopes of the lake and adjacent upland areas disturbed during site grading. In addition, we developed and implemented a plan for the salvage and restoration of the state-listed Endangered plant, Lyon’s Pentachaeta (Pentachaeta lyonii). Ex-situ populations of Lyon’s pentachaeta were established at Soka University Botanical and Research Center and Nursery, Calabasas. Prior to the grading of existing wetland and other habitats on site, Envicom Corporation biologists salvaged plants, cuttings, and seeds of native plants species. We also stored and propagated wetland plant materials at the Botanical and Research Center and Nursery for future use, and implemented a systematic program of weed eradication of various species, primarily through physical removal methods. A major target species of the efforts is the yellow star thistle, which is now advancing in the Santa Monica Mountains.