The Huffman-Broadway Group
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November 20, 2018 Brophy and Melissa Christensen 101 Goodhill Road Kentfield, California 94904 Subject: Biological Site Assessment for 101 Goodhill Road, Kentfield, Marin County, California Dear Mr. and Mrs. Christensen: Huffman-Broadway Group, Inc. (HBG) has completed a Biological Site Assessment report related to various improvements proposed at a single-family home at 101 Goodhill Road in Kentfield, Marin County, California. The evaluation herein complies with requirements of Item #36, Biological Site Assessment, in Marin County’s list of project application materials, County guidelines as spelled out in the document “Preparation of Biological Site Assessments,” and clarifications provided in conversations with you regarding your understanding of the needs for a biological report on the property at this time. The objective of this study was to provide a determination of the potential for the Study Area to support sensitive habitats as defined by state or federal regulation and/or pursuant to the California Environmental Quality Act (CEQA) including habitat suitable to support special status species of flora and fauna, and to evaluate whether the improvements to the single-family home and ancillary structures would result in significant impacts to these resources. The project architect, John Clarke of John Clarke Architects in Sausalito, requested the study in an effort to define biological constraints at the site prior to designing plans for site improvements. Our analysis included: (1) a review of the habitat characteristics of the site and species of plants and animals expected to utilize the site; (2) review of the California Natural Diversity Data Base (CNDDB) to determine if any populations of endangered, threatened, or rare species have occurred historically or are currently known to exist in the project vicinity; (3) a field survey of the site by an HBG biologist, and (4) an evaluation of whether the proposed project has the potential to result in impacts to sensitive habitats or special status species. The study included a general reconnaissance of the site by HBG wildlife biologist Gary Deghi on November 5, 2018. F:\Goodhill\Goodhill BSA 11-20-18.docx 1 PROPOSED PROJECT The subject property is a 27,009 square foot (0.62-acre) property located at 101 Goodhill Road in Kentfield, Marin County, California. The site is Assessor’s Parcel Number (APN) 074-261-10 owned by Brophy and Melissa Christensen. The project site is located on the San Rafael USGS 7.5-minute topographic map. Access to the site is from a driveway directly off of Goodhill Road which can be reached using Sir Francis Drake Boulevard to College Avenue and Woodland Road. The property is at the corner of Goodhill Road with Woodland Road. Tamalpais Creek runs along the west and north sides of the property. There is currently an existing house on the 0.62-acre lot at 101 Goodhill Road in Kentfield, Marin County. The location of the existing house and other existing features such as the garage, driveway, swimming pool and patio can be seen on the site survey prepared by William Schroeder and Associates and dated April 2014. Large-scale maps of the site survey will be submitted to the County along with this report and other materials needed for an application package for the project. The architect is awaiting definitive information regarding biological constraints at the site prior to designing site improvements, but the landowner’s project description would likely include plans to construct a new horseshoe driveway to access the front of the house, demolish the existing garage/carport, construct a new two-story addition with garage on the ground level, construct an accessory structure in the backyard, and reshape the existing pool. The current swimming pool has a slightly irregular design and the applicant would like to reshape the south side of the pool into a traditional rectangle and slightly reconfigure the patio around south side of the pool. They would also like to add an outdoor barbeque next to the pool. Once a new garage structure is constructed, portions of the existing concrete driveway closest to the creek on the north side of the property may be able to be removed and replaced with native landscaping to broaden the natural area between the driveway and the creek. EXISTING BIOLOGICAL SETTING The description of the biological setting for the property is based on a field visit to the site by HBG Senior Environmental Scientist Gary Deghi on November 5, 2018. The survey on this date included observations of the composition and distribution of plant species, wildlife observations, identification of sensitive habitats and a comparison of site characteristics for similarity to sites known to support special status species within the area. Tamalpais Creek runs along the west and north sides of the property. Tamalpais Creek is an intermittent stream that originates in the hills to the west of the property and flows through the Woodlands neighborhood. Tamalpais Creek eventually flows to Corte Madera Creek which flows to the San Francisco Bay. Tamalpais Creek adjacent to the subject parcel lacks qualities of a natural stream as the banks of Tamalpais Creek on the west side of the property have been reinforced with rock on both sides of the creek, and portions of the creek banks on the north side of the creek are also reinforced with rock. Nearly all canopy vegetation along the stream is composed of non-native tree species. Elevations on the 0.62-acre property range from 12 feet F:\Goodhill\Goodhill BSA 11-20-18.docx 2 msl on the northern part of the parcel to 18 feet msl on the south. Soil types on the property are Tocaloma-McMullin-Urban Land complex, 15 to 30% slopes on the western half of the property and Xerorthent-Urban land complex, 0 to 9% slopes on the eastern half of the property (USDA 2018). Plant Communities Typically, vegetation communities and habitats at project sites are identified based on the currently accepted List of Vegetation Alliances and Associations (or Natural Communities List) (CDFW 2010). The list is based on A Manual of California Vegetation, Second Edition (Sawyer and Keeler-Wolf 2009), which is the National Vegetation Classification applied to California. The habitat list does not include Urban habitats, though Urban Habitats are included in the classification of the California Habitat Relationship System (CHRS) (Mayer and Laudenslayer 1988). The property at 101 Goodhill Road is fully developed with a single-family home and associated facilities and landscaping and is surrounded by similar uses in the residential Woodlands neighborhood. The Project Site would be considered an Urban Habitat. Vegetation around the house at 101 Goodhill Road is entirely composed of non-native trees and shrubs planted for purposes of landscaping. Trees include magnolia (Magnolia sp.), privet (Ligustrum sp.), maples (Acer sp.), bamboo (Bambusa sp.), an apple tree (Malus sp.) and others. Other vegetation includes a rose garden, various planted non-native shrubs and groundcovers, and lawn. A single valley oak (Quercus lobata) and a number of olive (Olive sp.) trees and other vegetation can be found outside the property boundary along the Goodhill Road street frontage. The canopy and understory vegetation along Tamalpais Creek on the north and west side of the property is almost entirely composed of non-native species. The most common tree along the stream is the non-native privet, but bamboo, acacia (Acacia sp.), and planted fruit trees (Prunus sp.) are also common. Other non-native species include Monterey pine (Pinus radiata), pyracantha (Pyracantha sp.), bottlebrush (Callistemon sp.), and German ivy (Delairea odorata). Several native riparian trees are present along the stream adjacent to the property including one Coast live oak (Quercus agrifolia), and several small California bays (Umbellularia californica), white alder (Alnus rhombifolia) and box elder (Acer negundo), but these trees comprise a small portion of the tree canopy. Approximately 10 redwood (Sequoia sempervirens) trees present along the creek on the north side of the property, could be native trees but may have also been planted. Understory shrubs are mostly non-native French broom (Genista monspessulana), but a couple of small patches of native California blackberry (Rubus ursinus) can be found. Other vegetation adjacent to the stream bank include non-native grasses such as hedgehog dogtail (Cynosurus echinatus), wild oat (Avena fatua) and veldt grass (Ehrharta erecta). Small areas within the stream are vegetated with vegetation adapted for life in saturated soil conditions such as smartweed (Polygonum sp.) and tall flat-sedge (Cyperus eragrostis). F:\Goodhill\Goodhill BSA 11-20-18.docx 3 Animal Populations The habitats in the immediately surrounding area support a number of wildlife species typically found in urban settings in this part of Marin County. Trees and other vegetation on the property and within the adjacent riparian corridor provide nesting and roosting sites for birds, and cover and foraging habitat for species of birds, mammals, reptiles and amphibians. A number of wildlife species were documented at the site and the immediate vicinity during the field review conducted by Gary Deghi of HBG on November 5, 2018. All species documented are common to abundant in the region and would be expected in the habitats present at the site. Most of the documented species were birds that are expected in the habitat type present. Species documented at or near the site during the brief field reconnaissance included Anna’s hummingbird (Calypte anna), acorn woodpecker (Melanerpes formicivorus), California scrub-jay (Aphelocoma californica), common raven (Corvus corax), American robin (Turdus migratorius), chestnut-backed chickadee (Poecile rufescens), and house finch (Haemorhous mexicanus). Turkey vultures (Cathartes aura) were observed flying overhead during the site visit. Observed amphibians included California slender salamander (Batrachoseps attenuatus) (found under a log by the creek).