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Home My WebLink AboutNovember 10OSC FINAL_Minutes16-1110.docx 1 Los Altos Hills Open Space Committee Los Altos Hills Parks and Recreation Building FINAL Minutes of Regular Meeting November 10, 2016 Members and Associates Present: George Clifford, Nancy Couperus, Kit Gordon, Sharen Schoendorf, Jean Struthers, Wendie Ward, Sue Welch (Members); Richard Contreras, Karen Lemes (Associates) Members and Associates Absent: Alice Sakamoto (Member) Council Liaison Present: Gary Waldeck Member of Public Present: Peter Brown (LAH resident) Kjell Karlsson (LAH Finance and Investment Committee) Tina Tseng (LAH Engineer) Rosy Ko (Top Elegant Investment, LLC subdivision) Jeff Peterson (Top Elegant Investment, LLC subdivision) Steve Rabkin (24990 La Loma Drive) Steve Borlink (24990 La Loma Drive) 1. Call to Order and Approval of Minutes A. Roll Call. NC called the meeting to order at 9:00 am. B. Acceptance of Meeting Minutes. KG moved to accept with minor amendments the minutes of the October 13, 2016 meeting. GC seconded and vote was unanimously in favor (GC, NC, KG, SS, JS, WW, SW). 2. New Business 3. Continuing Business A. Presentation from Developers of Stirling (Top Elegant Investment, LLC) Subdivision. SW and SS recused themselves for proximity. At a Planning Commission Study Session on Sep 1, 2016 the developers presented an update of their project plans. At the Oct OSC meeting, the committee prepared a draft response to the developers’ updated project plans (Attachment A). In September, the developers requested to give a presentation at the Nov 2016 OSC meeting. At today’s meeting Jeff Peterson, Project Engineer asked to respond to OSC comments and to return to OSC in December to give an additional 1.5 hour presentation. He said the developers are revising the drainage (storm water) plans. Discussion included the concept of “gridding”; connections to open space easements (OSEs) on adjacent parcels; language for OSEs; the proposed “oak preservation easement”; the OSE along the eastern and northern borders; fencing issues; LAH building and fence setbacks. OSC requested developers send a copy of their presentation materials for the December OSC meeting to allow members time to review it. After further discussion, GC moved that OSC resubmit the October recommendation to the City Clerk as written with no changes. WW seconded and the vote was 5 in favor (GC, NC, KG, JS, WW) and 2 abstaining for proximity (SS, SW). B. Re-review of 24990 La Loma Drive (Lands of Rabkin and Vandergriff). OSC reviewed this project on 8/12/16 with a recommendation that included removal of barbwire fencing; dedication of an OSE along the southern portion of the property and a riparian easement 40 feet from the southern property line to protect Hale Creek (Attachment B). The developers requested to reduce the OSE to create a play area. After lengthy discussion, WW moved that OSC reviewed the development plans for the parcel at the last meeting and considers that the OSE proposed then meets criteria for OSE as defined in Town policies and ordinances; and that the OSC recommendation from the August meeting remain unchanged. The vote was unanimously in favor (GC, NC, KG, JS, SS, WW, SW). C. Byrne Preserve: i) Grassroots Ecology (GRE) Workdays. GRE has resumed invasive plant removal work at Byrne and will hold workdays every other Monday through December 19. Monday Nov 25 will be a creek bioengineering workday to install willow branches to stop erosion. ii) Request for Section of Fence. Grassroots Ecology (GRE) has requested approval and funds from OSC budget to install a 250-ft section of fence to protect a short reach of Moody Creek and the adjacent floodplain from horse activity (Attachment C). GRE is restoring this area as part of the 3- year grant from SCVWD supplemented with Town funds. After volunteers removed the tall, overgrown invasive plants from this area, it became more accessible to horses, which are now OSC FINAL_Minutes16-1110.docx 2 trampling the creek banks and dropping manure in the creek bed. The eroding banks and fresh manure are a serious water quality issue. Best Management Practices recommend fencing off creeks from livestock. OSC discussed options for fencing, which must be safe for horses and permeable to wildlife. Post and wire fencing (like Byrne perimeter fence) or split rail was suggested. GRE and barn manager, Torie Dye should be involved in planning. GRE reported that up to $1K is available from the SCVWD grant; additional funding could come from OSC budget. SW moved that OSC send a memo to City Manager, Carl Cahill, supporting Grassroots Ecology request for a wildlife permeable fence to protect the section of Moody Creek and the adjacent floodplain that is under restoration. OSC will consult with barn manager Torie Dye for recommendation for fence that will be safe for horses, but keep them out of the creek and restoration area. KG seconded and the vote was in 6 favor (GC, NC, KG, JS, WW, SW) and one opposed (SS). iii) Night Walk. Last month Grassroots Ecology sponsored a night walk in Byrne Preserve. Eleven attended and enjoyed seeing many nocturnal insects and other “nightlife” that inhabit the preserve. D. Creek Signage. KG suggested inviting Allen Chen, the new LAH Director of Public Works, to an OSC meeting introduce the OSC and review ongoing projects. E. Town Newsletter Articles. Articles from OSC are planned for future issues on Palo Alto Animal Services (AS), Dr. Albert Barnitz Byrne, and identification and management of pest plants. F. Wildlife Seminar on Snakes. JS will follow up on arrangements. G. Coyote Sightings. Nothing reported. H. Property Review Information Sheet. It was suggested OSC ask each City department to post on the Town web site a list of projects they are working on (as Public Works already does). KG spoke to Planning Director Suzanne Avila, who said this information is already available in the Manager’s Report and will keep OSC informed of ongoing projects. I. Subdivision Ordinance Update. KG reported this ordinance needs to be updated to meet new state code. OSC will follow the process, which includes public hearings. J. Follow-up on OSC Open Space Easement Recommendations. KG spoke with Planning Director about this, who said planning staff records this info and will provide these. KG added a section at the end of the property review information sheet. Approved OSEs eventually appear as Council Resolutions that are approved at Council meetings. Prior to that, OSEs are shown (or not) as conditions of development for properties at Fast Track or Planning Commission meetings. Members must check agendas for these meetings to follow the outcomes. 6. Planning A. Fence Permit Reviews. One set of plans was received and reviewed by AS. B. Site Plan Reviews. i) 25383 La Rena Drive (Lands of Heng; APN 175-38-007; #258-16-ZP-SD-GD). The reason for OSC review is construction of a new residence. KG and JS made a site visit and drafted a recommendation (Attachment D). A tributary of Purissima Creek flows along the back (western) border of the parcel; it has defined banks and is identified on the Eco-Atlas map. There are a number of heritage oaks and other trees on this part of the parcel and an old fence in the creek bed. The slope drops off steeply along the south border. Adjacent parcel to south has a large OSE. After further discussion, GC moved the OSC accept the draft recommendation to request dedication of a 25-foot open space easement from top of creek bank with easement continue to the oak/pine grove then along contour line 384 to eastern edge of property. Remove structures from easement including fence in creek bed. NC seconded and the vote was unanimously in favor (GC, NC, KG, JS, SS, WW, SW). ii) 12815 Deer Creek Lane (Lands of Chan; APN 175-43-047). The reason for OSC review is a 2-lot subdivision. GC, NC, KG, and WW made a site visit. Deer Creek flows through the subdivision and an OSE exists on one of the parcels. There are questions about the location of the top of bank of the creek on the lower lot and a possible OSE on the upper lot. Recommendation was deferred to allow other members to visit the site. iii) 14172 Amherst Court (Lands of Lakhani; APN 182-41-006; #373-16-ZP-SD-GD). The parcel has frontage on Amherst and Page Mill Road. Matadero Creek runs along the Page Mill frontage; a drainage easement exists in this area. The lot has dense oak coverage on the slope facing Page Mill. JS and SW volunteered to make a site visit and draft a recommendation. OSC FINAL_Minutes16-1110.docx 3 iv) 13875 Mir Mirou Drive (APN182-32-029). This and adjacent lots all have large OSEs. Recommendation was deferred to allow a site visit. 5. Communications from the Floor. A. Peninsula-South Bay Watershed Forum. Dec 6 at PCC 1-3 pm. Topic: Planning and Implementation of Stormwater Green Infrastructure in Local Watersheds. Learn about Bay Area’s storm water regulatory background, the pollutants of concern, benefits of Green Infrastructure, examples of local completed Green Infrastructure projects and design/maintenance issues. Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP) and Santa Clara Valley Water District have a Prop 1 grant for approximately $1M for local projects. B. Lehigh Quarry Update. Meeting will be held Nov 16, 2016 in Cupertino. 6. Open Discussion. 7. Adjournment. The meeting was adjourned at 11:21 am. Next Regular Meeting: Thursday, December 10, 2016 9:00 AM at LAH Parks and Recreation Building Attachment A: OSC Response to Stirling Subdivision Presentation at Sept 1, 2016 Planning Commission Attachment B: OSC Recommendation for 24990 La Loma Drive (8/12/16) Attachment C: Grassroots Ecology Proposal for Fencing Attachment D: DRAFT OSC Recommendation for 25383 La Rena Drive Final minutes were adopted as amended at the regular Open Space Committee meeting of Dec 8, 2016. 1 To: Suzanne Avila Date: October 18, 2016 From: Open Space Committee Subject: Comments & Recommendations on Stirling Subdivision Proposal Introduction On September 24, 2012 and January 14, 2014, the Open Space Committee wrote a set of recommendations for the proposed subdivision at 28030 Natoma Road, known as the Stirling Subdivision. Since January 2014, more information has been made available. Outlined below are current recommendations from the Open Space Committee based on information posted on the Town's website. Property Characteristics The 18.18 acre property has a wealth of environmental assets and geological complexities: • moderately steep to precipitous slopes • Matadero Creek tributary and headwaters • riparian corridor • large natural drainage swale of unstable colluvial soil, proposed for development • ephemeral creek emanating from bowl of swale • several small landslides and two large landslides • natural springs emanating from the largest of the landslides • Monte Vista Fault • productive, active well • extensive mature oak woodland in areas proposed for development • grassland meadow and chaparral brush • significant portion of site designated as Open Space Conservation Area • abundance of flora and fauna species on and around this site • the property serves as a critical hub for wildlife movement, linking major open space areas in this part of Town: • Arastradero Preserve • Matadero Creek • Poor Clare’s Monastery and lands to the east • Byrne Preserve 9-1.501 To the degree that the natural amenities, characteristics, topography, vegetation and wildlife, are preserved, the probability of acceptance of a given subdivision will be enhanced. 9-1.102(d) To preserve and protect the natural beauty and the established character of the community and, through good design, to provide for a harmonious relationship between completed subdivisions and the natural environment. Municipal Code, Title 9 Subdivisions 2 Open Space Committee Recommendation Summary The key recommendations and concerns from the Open Space Committee are listed here. The following pages provide additional details for each listed topic. 1. Environmental Impact Report (EIR) Recommended 2. Oak Woodland Open Space Easement 3. Eastern Boundary Open Space Easement 4. Fence Setback Between Sides of Newly Proposed Lots 5. Connection to Neighboring Open Space and Pathway Easements 6. Drainage Swale Open Space Easement (majority of proposed lot 7) 7. De-centralized Stormwater Management 8. Manmade Self-retaining Drainage Swale Easement 9. Steep Slopes and Creek Open Space Easement 10. Landslides and Spring Open Space Easement; Eliminate Subdrain System 11. Northern Boundary Open Space Easement (over pathway easement) 12. Stagger Lot Lines Relative to Existing Residences 13. Reduce Switchbacks and Length on Pathway; Obtain Agency Advice on Bridge 14. Correct Errors on Slope and LUF Worksheets 3 Figure 1: Map of Open Space Easement Recommendations 4 Figure 2: Town of Los Altos Hills Land Use Diagram Significant portion of property is in Open Space Conservation Area Open Space Conservation Area Within these areas, special measures should be taken to conserve the natural quality of the area and to avoid environmental degradation. Residences should be placed on the most buildable portions of lands designated OSCA and carefully sited so as to preserve existing trees, vegetation and wildlife habitat. LAH Town General Plan, Land Use Element 5 OSC Recommendations 1. Environmental Impact Report (EIR) We conclude that there is potential for significant environmental degradations from the proposed development with insufficient mitigations and therefore alternatives should be assessed. Significant details and elements are missing from the Initial Study/Mitigated Negative Declaration (IS/MND) and we urge the Town not to sign the IS/MND. Cumulative impacts have not been analyzed. An EIR would be in the best interest of the applicant and the Town. Agency review from Regional Water Control Board (RWQCB) and California Department of Fish and Wildlife (CDFW) with collaboration with California Native Plant Society (CNPS) is essential to protect Matadero Creek and the rich habitat from detrimental impacts not only on the property but extending to the Matadero watershed. The law firm Shute, Mihaly & Weinberger, representing Friends of Upper Matadero Creek, gives ample examples of shortcomings and inconsistencies in the IS/MND in their letter to the Town. Because of the legal shortcomings of the Initial Study, and the impracticability of mitigating impacts that will clearly result from the Project, the Town of Los Altos Hills ("Town") must reject the Initial Study and require an environmental impact report ("EIR") in its place to fully analyze the Project's impacts and propose a full range of alternatives. ... Town's failure to require an adequate review will leave the Town vulnerable to legal challenge. Letter to Town of Los Altos Hills from Shute, Mihaly & Weinberger representing Friends of Matadero Creek , January 20, 2016 CEQA (California Environmental Quality Act) requires the Town, as the Lead Agency, to identify significant environmental impacts, whether direct, indirect, or cumulative, and to avoid or mitigate those impacts to less-than-significant levels, if feasible. The significant size of this property, combined with its environmental value (as discussed at length below), means that correspondingly large efforts must be taken to address this proposed subdivision’s overall impacts. 6 2. Oak Woodland Open Space Easement We recommend an open space easement (OSE) for the mature oak woodland extending from the entrance of property to the center of the property including portions of proposed roadway, portions of lots 1 & 2, bowl of swale at proposed lot 7, and landslide in proposed lots 5 & 6. See Figure 1 for easement recommendation. See habitat designation in Figure 3. • The developer's oak woodland easement proposal at the September 1 Planning Commission Study Session is insufficient in both area and protection. Their easement language does not appear to protect oaks from removal. We recommend standard OSE to protect oak woodlands. • Oak woodlands cover approximately 11 acres of site providing plethora of benefits for soil stability, habitat, aesthetics, reduced runoff and increased groundwater to this site and neighboring areas. • Oak trees at landslide and bowl of swale preserve hydrological function and soil stability. • Road layout should minimize oak tree removal. Road can exist within OSE. Trees have a number of potential benefits...: increased nutrient uptake, reduced stormwater runoff through rainfall interception and evapotranspiration, enhanced soil infiltration, soil stabilization, increased aesthetic appeal, wildlife habitat, and shading. Trees have been shown to capture storm-water, reducing the runoff volume directly and potentially reducing peak flows. Tree roots can also directly enhance infiltration rates. WRA Literature Review for Bay Area Storm Water Management Agency Association (BASMAA) September 14, 2016 Policy 2.2 Minimize disturbance of the natural terrain and vegetation. Preserve and protect native and naturalized plants, with special attention to preservation of unique, rare or endangered species and plant communities such as oak woodlands. Policy 2.3 Preserve and protect Heritage Trees, including native oaks and other significant trees, on public and private property. LAH General Plan, Conservation Element 7 Figure 3: Oak Woodland & Habitat Map Oaks at landslide Oaks at swale Oaks at roadway, parts of lots 1&2 o 8 3. Eastern Border Open Space Easement We recommend an OSE of at least 25 feet on the eastern border of the property to prevent "suburban gridding" of properties within this proposed subdivision and with neighboring properties. The Subdivision Ordinance requires that significant thought to be given to creating a subdivision that maintains the open space characteristics of both the Town and the adjacent existing neighborhoods. This property supports resident wildlife species and serves as an established and heavily used hub for wildlife movement through the Town, therefore the impact of high-density development on wildlife must be considered, for the sake of the surrounding neighborhood. It is the Town’s responsibility to preserve wildlife habitat (which includes its migratory routes) as much as possible in the face of permitted development, and it also needs to protect surrounding neighborhoods from permanent, significant changes to the flow of wildlife. Consistency with Town policies can easily be achieved by assuring that although the subdivision may reduce the existing routes, it should not eliminate any. • A 15 foot easement was proposed by the developer at the September 1 Study Session is not adequate. At least 25 feet is recommended due to proximity with neighboring properties and abundance of wildlife accessing this property. • The developer's proposal to include property line fences within an open space easement is inconsistent with the Town's open, rural community goals and with open space easements. • Any fencing in the open space easement, even “wildlife-friendly,” is dangerous to the wildlife moving through it. For example, deer panic and flee on perceiving a threat, and will crash headfirst into such fences causing injury or death. • The existing wildlife-barrier perimeter fence along eastern and northern border should be removed. Policy 1.7 To the extent possible, link open spaces together visually and physically to form a system of open spaces. Policy 1. 8 Ensure that land uses and structures are compatible with the general open space quality of the planning area. Policy 2.6 New residential subdivisions shall provide open space for recreation in order to meet their appropriate share of local recreation needs. LAH General Plan, Open Space Element Policy 2.7 Avoid the development of environmentally sensitive areas that are rich in wildlife or of a fragile ecological nature, such as areas of rare or endangered species of plants, or riparian areas. Goal 3: Maintain and enhance the integrity of wildlife habitat. Section 315: Planning for natural movement of wildlife can help avoid, minimize and compensate for serious negative impacts on wildlife and humans. Areas that link wildlife habitat have become vital because native animals such as deer, fox, bobcat, and coyote are prevented by roads, fences, homes and other development from moving freely as they once did LAH General Plan, Conservation Element 9 4. Fence Setback Between Sides of Newly Proposed Lots We recommend a 10-foot fence setback from sides of property lines, creating 20-foot breaks in fencing. See Section 3 above for reference to preventing the "gridding" of properties and preserving established wildlife passage. • Packing in a large number of lots with no separation is antithetical to the Town’s goals of preserving rural, open space environments. • The rich habitat value of this site should continue to provide passage for the Town's native wildlife. A continuous, impenetrable grid of fences would limit wildlife habitat. 5. Connection to Neighboring Open Space and Pathway Easements We recommend that open space easements adjoin existing open space and pathway easements on neighboring properties, specifically: • 13456 S Fork Lane • 13440 S Fork Lane • 13452 S Fork Lane • 13300 Country Way • 13311 Country Way • 13145 Byrd Lane • 13263 Simon Lane (pathway easement) • 13315 Simon Lane (existing wildlife access in opening in fence) • 13253 Simon Land • 28025 Natoma • 12400 Melody Lane 10 6. Drainage Swale Open Space Easement (majority of proposed lot 7) In 2012, 2014 and now in 2016 we strongly recommend an open space easement on the large unstable drainage swale in the center of the property, covering most of proposed lot 7. Several Town policies require protection of natural swales, drainage areas and geologically unstable areas. Drainage is especially important on this steep, complex property. A house is proposed in the center bowl of the swale on unstable soil. The swale bowl collects stormwater from this site and uphill neighboring properties. Geologically, this area is labeled Quaternary Colluvium, Qc, on diagram in Figure 4. The Romig Geologic Hazard Investigation reports the entire Qc region as a colluvial swale, with unstable, unconsolidated soil. However, the maps in IS/MND do not show or mention the bowl of the swale and no mitigation is offered for the loss of this natural drainage swale. A relatively broad shallow swale was present in the central area of the site. An ephemeral creek descends from the swale down to the west to the flowing creek. Page 5 of Romig Geologic Hazard Investigation, May 2014 An additional significant site feature is the broad generally bowl-shaped drainage swale (lot 7), which extends from above the water tanks a portion of the distance downslope to the creek in the center part of the site. The feature narrows where the slope increases to the west. Active gully erosion is present in the narrowing portion of the swale incising the surface soils. The gully extends down the slope to the north-south flowing perennial creek in the west. There appeared to be evidence of soil creep the surface soils of the broad swale. Page 17 of Romig Geologic Hazard Investigation, May 2014 9-1.406c12: The preliminary map shall contain the following information: Unusual features of terrain, such as rock outcrops, tree masses, watercourses, in and adjacent to the proposed subdivision. LAH Municipal Code, Title 9 Subdivisions The bowl of the swale is an extension of the creek and provides these functions to this property and all uphill properties: • collects and directs surface and subsurface stormwater • slows surface and subsurface water flows • increases groundwater recharge for local well usage • filters contaminants from runoff • reduces runoff and reduces landslide risk of the ephemeral creek in the steepest section by sinking stormwater into underlying sandstone 11 Figure 4: Soil and geology of property from Romig Geologic Hazard Investigation • The unstable, unconsolidated Qc (colluvial) soil is not suitable for development as noted in the geologic hazard report, hence, the developer's proposal to excavate 5000 cubic yards of this soil to create an engineered fill. See Figure 5 below. • The swale provides drainage for the surrounding lands beyond the property boundary, including uphill neighboring lots on Simon Lane, section of Natoma Road and parts of Poor Clare's lands. Surface and subsurface waters flow to this swale. • Vegetation on all colluvial soil, including mature oaks in bowl of swale (see Figure 3) should be left in place to stabilize soil and retain hydrological function. • The ephemeral creek emanating from the bowl of the swale should be protected from development and should not have 260 feet of drainage pipes installed over it. Construction, maintenance and repairs will impair this unstable area. • The lower steep swale and ephemeral creek will have a greater likelihood of sliding without the upper bowl of swale to slow and direct flow to shallow aquifers. A slide at the ephemeral creek would take the developer's proposed drainage pipes with it. 12 9-1.602 All lots or parcels shall be designed so as to take maximum advantage of, while still preserving, the basic natural characteristics of the land. The subdivider shall demonstrate, through tentative lot design and development plans, that careful consideration has been given to the design and size of the lots or parcels, the probable types of improvements, access, support facilities, minimal alteration of topography, protection of mature vegetation, and the retention of existing natural drainage courses. (§ 6:20, Ord. 180, as amended by § (part). Ord. 232, eff. July 3. 1976) Municipal Code, Title 9 Subdivisions Policy 2.5 Steep slopes, canyons and ravines generally in excess of 30% slope, as well as natural swales and drainage channels, and geologic hazard areas within areas designated for residential development shall be left undisturbed and preserved in their natural condition to the maximum extent feasible. Policy 2.6 Limits on the development of individual residential lots shall be determined based on evaluation of such factors as natural vegetation, topographic characteristics, soils and geology. LAH Town General Plan, Land Use Element Policy 1.1 Avoid fencing, piping, and channelization of creeks when flood control and public safety can be achieved through measures that preserve the natural environment and habitat of the creek. Policy 1.2 Work with the Santa Clara Valley Water District and other relevant regional agencies to enhance riparian corridors and provide adequate flood control by use of low impact restoration strategies. Policy 1.3 Preserve the integrity of riparian corridors as unique and environmentally sensitive resources. Policy 3.1 Maintain and protect creeks and riparian corridors for wildlife that use this resource for food, shelter, migration and breeding. Policy 5.1 Keep or restore major drainage courses in their natural condition insofar as possible because of their importance in supplying major vegetation, land forms and wildlife habitat, and storm drainage. Policy 5.2 Protect the Town’s groundwater from the adverse impacts of urban uses. LAH Town General Plan, Conservation Element Policy 1.2: Protect and maintain those areas necessary to the integrity of natural resources and processes, with special emphasis on, but not limited to, the groundwater recharge and drainage system, open spaces vital for wildlife habitat, open spaces suitable for agriculture, and other areas of major or unique ecological significance. LAH Town General Plan, Open Space Element 13 Figure 5. Dashed red line shows area for excavation of 5000 cubic yards colluvial soil in drainage swale. Outline of proposed house is shown. 7. De-Centralize Stormwater Management An extensive centralized drainage system has been proposed by the developer piping stormwater runoff from nine proposed lots to one central retention basin (to be built in the unstable colluvial swale we recommend for conservation). We recommend managing stormwater runoff for each property at each property site rather than one central location. • Stormwater basins at each home site, preferably underground, pose less erosion risk to the creek than one large outfall of stormwater from all homes and roadways. • Extensive underground piping is not recommended in steep terrain and across earthquake fault. Ground shifts can create pipe separations, especially where soils are documented to be highly expansive and unstable. • Extensive piping across the property will almost certainly create more ecological degradation during construction and subsequent maintenance and repairs. Tree roots will be affected. • The proposed central outfall is piped over an ephemeral creek within an open space easement. This should not be allowed. Construction, maintenance and repairs on this steep ephemeral creek will impact water quality, erosion and habitat. 14 Figure 6: Proposed Centralized Stormwater Drainage System Lower blue trapezoid is retention basin; 5 blue ovals are manmade self-retaining swales 8. Manmade Self-Retaining Drainage Swale Easement In addition to a centralized retention basin serving all proposed lots, drainage for the proposed subdivision includes creation of manmade self-retaining swales. We recommend an OSE on all manmade drainage swales in proposed lots 1-4 and 9 to preserve their stormwater function. (See Figure 6). • We are concerned that the location of swales relative to established oak trees may risk oak tree health. • We are also concerned that swales located above grade of homes may create risks to house foundations and have limited functionality in storm events greater than their designed capacity. • The manmade self-retaining drainage swale proposed on lot 4 is up hill from 13145 Bryd Lane. Are precautions needed to protection this neighbor? • We are concerned about the long-term management of these manmade self- retaining drainage swales. More details are needed. 15 9. Steep Slope and Creek Open Space Easement We recommend OSE on all slopes of 30% including the headscarp of the landslide on proposed lots 5 & 6, the steep slope adjacent to the drainage swale on proposed lot 8 (contour lines 460-470), and portion of lot 9 at existing building. We recommend OSE along Matadero Creek at the southern and western property boundary and over the bowl of the drainage swale and its ephemeral creek (most of proposed lot 7). This area is part of the headwaters of Matadero Creek. • The IS/MND fail to accurately describe or show the existing condition of the creek. The creek is impaired with deeply incised, highly eroded banks. Proper description is imperative for evaluating impacts from the proposed subdivision. • An OSE is recommended over the entire southern and western property boundary with slopes more than 30%. • We recommend extending the proposed OSE to include the non-contiguous sections of grades steeper that 30% on portions of proposed lot 9 (at existing building), lot 5 (at the landslide & oak grove), lot 6 (at the landslide & oak grove), and lot 8 (along faultline, swale and oak grove). • Several slides exist on steep slopes. Only two major slides are marked on plans. Figure 7. Slope classification of site. The upper red section between lots 5 & 6 is the headscarp of the upper landslide. 16 10. Landslides and Spring Easement, Eliminate Subdrain on Landslide We recommend an OSE on marked landslide areas and spring on proposed lots 5 & 6. We also recommend that the landslide not be divided between two property owners. We also recommend not to install over 950 feet of drainage pipes in the landslide and open space easement. • The headscarp of the upper landslide has slope in excess of 30% with mature oak trees helping to stabilize soil. • The Cotton, Shires and Associate report of August 20, 2014 recommends drawing the property line "to avoid splitting the displaced mass of the upper Dormant Landslide" unless "acceptable to the Town." We recommend that it not be acceptable to the Town to split the landslide between two owners. • When landslides occur, riparian vegetation and creek function are at risk. Development should be restricted in these areas. • A spring exists in the upper landslide and a subdrain system has been proposed. The maintenance of the drain and its responsibility and liability should reside with one property owner. • The above mentioned subdrain system of over 950 feet of piping is proposed in the steep, oak grove section of the landslide and in a steep, sensitive OSE. We don't recommend its construction but rather keep development away from the landslide so as to not require subdrains. More details are needed about impacts to the surrounding environment during construction, maintenance and repairs. • The landslide subdrain in the IS/MND is less than 300 feet. The developer's proposed subdrain is over three times this length at 950 feet. The IS/MND needs to document the developer's proposals. Policy 2.5 Steep slopes, canyons and ravines generally in excess of 30% slope, as well as natural swales and drainage channels, and geologic hazard areas within areas designated for residential development shall be left undisturbed and preserved in their natural condition to the maximum extent feasible. Policy 2.6 Limits on the development of individual residential lots shall be determined based on evaluation of such factors as natural vegetation, topographic characteristics, soils and geology. LAH Town General Plan, Land Use Element 9-1.604 Where difficult terrain or other unusual conditions exist, lots larger in area than the minimum shall be provided as necessary to accomplish the purposes set forth in this chapter, whether due to features of grade, topography, the probability of the land being subjected to slides, inundations, or other hazards. LAH Municipal Code, Subdivision Lot size and requirements 17 11. Northern Boundary Easement We recommend at least 25 foot OSE along the northern boundary overlapping the pathway easement and its connector pathway to the roadway. • To avoid gridding with adjacent properties, an OSE is recommended. • The proposed pathways at the northern boundary and its connector to the proposed road will facilitate wildlife passage and connection to adjacent easements. • This area is within the Open Space Conservation Area. • An OSE will insure structures such as fences or gates will not be built, or if the path is not built, the OSE will still protect these passages for habitat and aesthetics. 12. Stagger Lot Lines From Existing Residents Staggering the proposed lot lines relative to existing homes will improve aesthetics and meet the Town's goal for open, rural atmosphere. We recommend modifying property boundary lines for lots 1-4 to be offset from existing properties. 13. Reduce Switchbacks on Pathway, Agency Advice on Bridge The proposed northern boundary pathway and bridge across Matadero Creek will significantly impact erosion and integrity of vegetation in this very steep and environmentally valuable area. The creek is already impaired with deeply incised banks. We recommend fewer switchbacks and a steeper path. Paths with slopes of 20-30% are acceptable on other pathways. • The pathway proposed by the developer is unnecessarily long causing extensive vegetation loss. 3700 feet of pathway is proposed for 980 feet of distance, disturbing over 18,500 square feet of high quality habitat and riparian vegetation. • The loss of vegetation on steep slopes for construction of the path will increase storm water runoff and erosion locally and downstream. • Loss of vegetation will impact wildlife habitat. • Provide details on bridge design, construction, and access during construction. • Regulatory agencies CDFW and RWQCB should be consulted for bridge construction on this impaired creek. The following excerpt from the WRA Environmental Report erroneously defines riparian vegetation and thereby falsely excluded this project from CDFW jurisdiction. Any vegetation in the riparian area is considered riparian vegetation; bays and willows alone do not only define riparian vegetation. In areas where hydrophytic vegetation including willows (Salix sp.) and California bay was present at or below top of bank, the outer edge of the riparian vegetation canopy was delineated as the extent of CDFW jurisdiction. In areas where the vegetation above top of bank was dominated by upland vegetation, including coyote brush (Baccharis pilularis), and poison oak, this vegetation was excluded from riparian CDFW jurisdiction. WRA Environmental Consultants Report, April 1, 2016 18 14. Correct Errors on Slope and LUF Worksheets Several errors exist on the slope and LUF worksheets. Errors found so far are contour lines 396, 404 and 410 on total parcel calculations, contour line 394 for proposed lot 6, contour lines 480-490 on proposed lot 9; all are lower than measured. For proposed lots 8 & 9, contour lines 370-390 are mostly excluded from worksheets. Please provide corrected contour line calculations for slope and LUF worksheets or provide new worksheets if new lot lines are proposed. ---end of document --- AttachmentB_OSC16‐1110_FinalReview24990 La Loma Drive16‐0820docx.docx            12/15/16  1  Open Space Committee Property Review Information  Property address      24990 La Loma Drive      Lands of __Rabkin_____________________________ APN_____336‐32‐023________  Planner________Suzanne Avila______________ Project number ______________________________________  Reason for OSC review: _____ New residence,  ____ Second Unit,  _XXX_ Addition/major remodel  Other (specify)_______________________________________________________________________________________  OSC Reviewers (initials)__NC, WW, GC_ Date of site visit___7/21/2016___  SLOPE:    Average slope of lot ___unknown_____  Areas with slope ≥30% YES     CREEKS  Creeks or waterways through parcel?  Seasonal stream in ravine at rear (South) of  lot  Name of creek. Shown on USGS map? SCVWD creek map? LAH Hazard Map?  Tributary to  Hale Creek on southern boundary of property  Evidence of bed, banks, Official High Water Mark? No  Condition of banks? N/A  Existing riparian or OSE along creek on this property or nearby parcels? Yes: see below.  Proposed setbacks for structures?  N/A    TREES  Heritage oaks? None  Groves of significant trees? Lower (south) portion of lot  Trees proposed for removal (Heritage oaks or other; number and species)? None    WILDLIFE CORRIDORS  Check 2006 Live Oak Associates map (not official)  Evidence of wildlife (e.g., deer trails, spoor)?  Deer trail crosses east‐west across the southern steep portion of the property.  The wildlife corridor map shows the lower part of the property as part of a  larger wildlife corridor.      EXISTING FENCING:  AttachmentB_OSC16‐1110_FinalReview24990 La Loma Drive16‐0820docx.docx            12/15/16  2  Identify location and type of existing fencing  Check that fencing on plans agrees with fencing on the ground  Note any fence that does not meet current fencing regulations  Old barbed wire fences crossing east‐west in rear of property and along the  eastern edge, as shown on the Topographic Survey in the plans.      OPEN SPACE EASEMENTS   Check Town records for existing CE or OSE on this property or adjacent and nearby parcels   Identify areas where OSE  may be appropriate (slope ≥30%, significant trees, creeks, drainage  swales)   See attachment showing the southern portion of the property included in the  Town’s Open Space Conservation Area.     Open Space Easements exist on two nearby properties at 24910 and 24920 La  Loma Court  to the east of this site, encompassing the same tributary stream.      SEPTIC FIELD LOCATION   Note location if applicable  Septic fields, sewer and approved drainage installations are generally allowed in OSE        OSC RECOMMENDATION FOR THIS PROPERTY  • Remove the barbed wire fences.  • Do not allow removal of any mature oak trees on the property.  • Create an OPEN SPACE EASEMENT,  as defined follows from the  Topographic Survey dated 12/16/2015:  An area in the southern portion of the lot enclosed by the southern,  eastern, and western boundaries of the lot AND a line extending from the  intersection of the 560’ contour line with the eastern border to the   intersection of the 546’ contour line with the western border.  See  attached image of proposed easement. See area shown in red on the map  below.  • Create a RIPARIAN EASEMENT, as defined follows from the Topographic  Survey dated 12/16/2015:   AttachmentB_OSC16‐1110_FinalReview24990 La Loma Drive16‐0820docx.docx            12/15/16  3  An area extending from the southern property line of the lot to a line  parallel to at it at a distance of 40’. See area shown in green on the map  below.       from Topographic Survey, 12/16/2015    AttachmentB_OSC16‐1110_FinalReview24990 La Loma Drive16‐0820docx.docx            12/15/16  4        OPEN SPACE CONSERVATION AREA  Town of Los Altos Hills Land Use Diagram, March 16, 2010    Approved  8/12/2016 by vote of Open Space Committee  George Clifford & Nancy Couperus,  OSC co‐chairs    FOLLOWUP   Date Development Plans approved:  __________________ Fast Track meeting  __________________ Planning Commission meeting  __________________ City Council meeting  Conditions of approval related to open space  Note changes from OSC recommendation   Memorandum To: Open Space Committee, Town of Los Altos Hills From: Kristen Williams, Project Manager, Grassroots Ecology Date: November 9, 2016 Re: Fence for riparian area at Byrne Preserve Grassroots Ecology would like to request that the Town of Los Altos Hills provide support to install a 250-foot fence to protect a riparian restoration area within Byrne Preserve from livestock activity which is impacting the creek and restoration progress. The style of fence should keep horses out of the protection area but still allow for wildlife to pass through. We believe the existing fence along Altamont Road may be a good example, but suggest Westwind Barn be consulted about what would best keep the horses out of the area. We are hoping that the Town maintenance staff would be able to complete the installation. Grassroots Ecology has up to $1,000 available to cover materials and supply costs through our current grant from the Santa Clara Valley Water District. Background The majority of Grassroots Ecology’s stewardship work at Byrne Preserve is focused on the Moody Creek tributary that runs through the grassland. Within this area we have spent great effort on restoring the floodplain at the bottom of the tributary. In the past months we have noticed an increase in traffic from horses in this zone which is accompanied by horse manure building up in the creek bed, as well as accelerating erosion along the creek bank. Our key concerns with horses in this area are: Water Quality  We are concerned about the water quality of Moody Creek due to increased levels of manure and erosion present in this area. Biodiversity  This area is uniquely diverse with native plants including an impressive stand of narrow leaf milkweed (the host plant of Monarch butterflies) as well as golden currant.  Additionally, because this area provides butterfly habitat that is on the decline in our region, an anonymous donor has made a contribution to plant more milkweed in this area this winter. Increased Restoration  While this area has great native biodiversity it is also highly infested with invasive species and therefore a location we would like to increase restoration efforts.  This past summer and fall we installed a solarization plot in this area to minimize the invasive seed bank and prepare the area to seed with native grasses. We put up temporary fencing and monitored the area regularly but still had to remove the solarization project prematurely due to horse activity in the area.  If this area were protected from the disturbance of horses we could utilize a broader range of restoration strategies such as sheet mulching, solarization, seeding, and container planting. Volunteer Engagement  The Moody Creek tributary floodplain has been a focus of this project not only because it is an area that is in great need to be restored, but also because it is an ideal spot to work with volunteers. Last year we worked in this area during more than 70% of our volunteer workdays. It is flat, easy to access, does not have poison oak, and has a lot of invasive species that need to be removed. Fencing this area off would protect the hard work of community members from livestock damage and provide a work zone safe from horses.  Additionally, in July, Grassroots Ecology began implementing a three year grant from the Santa Clara Valley Water District to increase riparian restoration in Byrne Preserve with the Moody Creek tributary and floodplain being the main focus of the project. Protecting this area from horse activity will greatly increase the success of the project. Proposed Fence Area AttachmentD_OSC16‐11110_DraftReview 25383 la rena.docx           12/15/16 1  Open Space Committee Property Review Information  Property address___25383 La Rena Dr__________________________________________________________  Lands of _Regina & Ben Heng_________________________ APN____175‐38‐007_________  Planner____Marni Moseley___________ Project number __File: 258‐16‐ZP‐SD‐GD__________  Reason for OSC review: _X_ New residence __X_ Second Unit _____ Addition/major remodel  Other (specify)_______________________________________________________________________________________  OSC Reviewers (initials)_____KG, JS_________ Date of site visit________11/8/16__________  SLOPE:    Average slope of lot: Unknown, missing LUF/Slope calculations  Areas with slope ≥30%?  Yes  Check slope/LUF worksheet for subdivision: Are all contour lines recorded? Look for  discrepancies between adjacent contour lines.    CREEKS  Creeks or waterways through parcel? Yes, tributary of Adobe Creek  Name of creek. Shown on USGS map? SCVWD creek map? LAH Hazard Map? EcoAtlas? Yes  Evidence of bed, banks, OHWM? Yes  Condition of banks? Old fence in creek bed  Existing riparian or OSE along creek on this property or nearby parcels? large conservation  easement on southern border  Proposed setbacks for structures? Remove existing structures from creek setback    TREES  Heritage oaks? Yes  Groves of significant trees? Several pine and oaks  Trees proposed for removal (Heritage oaks or other; number and species)?    WILDLIFE CORRIDORS  Check 2006 Live Oak Associates map (not official) Yes  Evidence of wildlife (e.g., deer trails, spoor)? Yes, many animal trails. Large coyote near  creek.    EXISTING FENCING:  Identify location and type of existing fencing: Old fence in creek bed  Check that fencing on plans agrees with fencing on the ground  Note any fence that does not meet current fencing regulations: Old fence in creek bed    AttachmentD_OSC16‐11110_DraftReview 25383 la rena.docx           12/15/16 2    OPEN SPACE EASEMENTS   Check Town records for existing CE or OSE on this property or adjacent and nearby parcels.  Identify areas where OSE may be appropriate (slope ≥30%, significant trees, creeks, drainage  swales).  Conservation easement on southern border, across creek.     PATHWAY EASEMENTS   Check Town records for existing or newly proposed PE on this property or adjacent and  nearby parcels. Should OSE be placed on PE? Pathway along La Rena Lane    SEPTIC FIELD LOCATION   Note location if applicable: N/A  Septic fields, sewer and approved drainage installations are generally allowed in OSE    OSC RECOMMENDATION FOR THIS PROPERTY  Draft recommendation (from reviewer)    25 foot open space easement from top of creek bank with easement continue to the  oak/pine grove then along contour line 384 to eastern edge of property. Remove  structures from easement including fence in creek bed.    Final OSC recommendation (after formal OSC review)    25 foot open space easement from top of creek bank with easement continue to the  oak/pine grove then along contour line 384 to eastern edge of property. Remove  structures from easement including fence in creek bed.      FOLLOWUP   Date Development Plans approved:  __________________ Fast Track meeting  __________________ Planning Commission meeting  __________________ City Council meeting  Conditions of approval related to open space    Note changes from OSC recommendation (From Planning Staff):   