TO: PLANNING COMMINSSION

FROM: JAYNI ALLSEP, CONTRACT PLANNER

SUBJECT: FILE #30003: REVIEW OF DRAFT ENVIRONMENTAL IMPACT REPORT FOR THE TIBURON GLEN PRECISE DEVELOPMENT PLAN (PD #22) TO CREATE EIGHT BUILDING SITES ON A 26.03 ACRE PARCEL; 3700 BLOCK OF PARADISE DRIVE NEAR NORMAN WAY; XANADU PROPERTY HOLDINGS, INC., OWNERS; ASSESSOR’S PARCEL NO. 39-241-01

MTG. DATE: OCTOBER 9, 2002 REVIEWED BY: SA

PROJECT DATA

Address: Vicinity of 3700 Block of Paradise Drive

Assessor’s Parcel Number: 39-241-01

File Number: 30003

General Plan: Low Density Residential

Zoning: RPD (Residential Planned Development)

Current Use: Vacant

Owners: Xanadu Property Holdings, Inc.

Applicant: Tom Newton, Planning Advisory Corporation

Date Complete: February 15, 2001

An application has been filed by Xanadu Property Holdings, Inc. for a Precise Development Plan for development of a 26.03-acre parcel into eight (8) single-family residential lots. The project site is located on the northeast side of the Tiburon Peninsula in the Town of Tiburon. The irregularly shaped parcel is situated on the southwest (upslope) side of Paradise Drive and wraps around the existing Norman Estates neighborhood.

A Draft Environmental Impact Report (DEIR) has been prepared for this project by the firm of Nichols•Berman, and is currently being circulated for a 45-day public review and comment period. The comment period is scheduled to conclude on October 14, 2002, at 5:00 p.m. Copies of the DEIR are available for review at Tiburon Town Hall and at the Belvedere-Tiburon Public Library during business hours. Copies may also be purchased at Tiburon Town Hall for $45. The Planning Commission previously received its copies of the DEIR, and should bring them to the meeting. After the conclusion of the comment period, the Planning Commission will hold a formal public hearing to assess the adequacy of the DEIR. Subsequent public hearings will be held on the merits of the project application.

This is a courtesy meeting sponsored by the Town of Tiburon to provide a forum for the receipt of verbal comments on the DEIR. Traditionally, the Town of Tiburon has utilized regularly scheduled Planning Commission meetings for this purpose; however, there is no requirement for a formal setting at which to accept verbal comments, and no quorum of the Planning Commission is necessary to proceed with the accepting of public comments on the DEIR.

At this meeting, Staff will present a brief report describing the major findings of the DEIR. Any person may make verbal comments, and/or submit written comments on the DEIR, at this meeting. Comments should focus on the sufficiency of the DEIR in discussing possible impacts on the environment, ways in which adverse impacts might be minimized, and alternatives to the project. Following the conclusion of public comments, the Planning Commission may provide comments on the DEIR if it so chooses.

PROJECT DESCRIPTION

The proposed project involves the creation of eight residential lots for development of one single-family home and the installation of ancillary residential improvements on each lot. Individual lots would range in size from 33,600 to 413,625 square feet (0.77-9.50 acres). As proposed, each lot would consist of a building envelope where development would occur, and private open space that would remain undeveloped. The building envelopes would range in size from 6,250 to 12,130 square feet. Lots 1 through 6 would be located west of Norman Way and would be accessed from two roadways connecting jointly to Paradise Drive. Lots 7 and 8 would be located east of Norman Way and would be accessed from a single roadway from Paradise Drive. The proposed Precise Development Plan (PDP) shows a conceptual house footprint and driveway on each lot. Approval of the pending application, if granted, would not result in construction of housing units by the applicant. Instead, homes would be built by individual lot owners after the property is subdivided, subject to Design Review approval. The PDP includes a schematic landscape plan that lists species proposed for planting along internal private access roadways.

SUMMARY OF KEY DEIR FINDINGS

Land Use and Planning

Section 4.0 of the DEIR presents an analysis of the project’s consistency with the Town’s General Plan and Zoning Ordinance, and the Marin County Paradise Drive Visioning Plan. The DEIR employs the terms consistent, partly inconsistent, and inconsistent to assess the project’s conformance with public plan and zoning policies.

The DEIR concludes that the proposed project would be inconsistent with several Town policies that discourage development on steep slopes and encourage development that minimizes grading to preserve existing landforms and other resources.

In response to comments made during the public scoping process, Section 4.0 of the DEIR includes a detailed discussion of prime open space. Diagram OSC-3 of the Open Space and Conservation Element identifies the subject property as "potential open space." The element lists several "characteristics and attributes" that make a site "worthy of permanent protection to the extent such protection is feasible" and to use during the Town’s development review process to evaluate prime open space. Based on these criteria, the DEIR concludes that numerous defining characteristics are present on the property, and major portions of the project site qualify as "prime open space".

Geology

The preliminary geotechnical report and DEIR confirm that landslides of various types blanket parts of the site, both within and adjacent to areas of proposed development. Repair and elimination of all landslides on the property, as required by the Town’s landslide policy, would require a combination of repair methods, including a grading operation that would involve thousands of cubic yards of soil. The DEIR recommends mitigation measures that would reduce geologic impacts to less-than-significant levels. The type and extent of stabilization required for landslide repair would depend on the mitigation strategy that is determined to be most appropriate in order to implement the Town’s landslide repair policy while minimizing the secondary hydrologic, biological and visual impacts that would likely result from grading. Secondary impacts from grading are discussed under the respective headings below.

Hydrology

Project implementation would result in coverage of an estimated 2.1acres of impervious surface (building envelopes and access roads), generating an increase in runoff from the site of approximately 8.1% over existing conditions. Project implementation would result in increases in the 100-year peak discharge of storm water ranging from 2.4% to 19%. While these increases are minor to moderate, it is not yet known whether the existing roadway culverts under Paradise Drive have adequate capacities to accommodate the increased flows without flooding. Although there is the potential for significant impacts to result from increased water runoff and erosion as a result of this project, the DEIR recommends mitigation measures that would reduce these impacts to less-than-significant levels. Mitigation measures include the replacement of the Paradise Drive culverts if it is determined they are of insufficient capacity to convey the 100-year peak flows from the property.

The DEIR identifies several drainageways and six watersheds on the project site. In addition, a spring and two seeps are located on the property. Landslide repair and stabilization would, at a minimum, alter the character of most of the principal drainageways. Depending on the landslide repair techniques that are employed, a majority of the site’s seasonal drainages, as well as the spring and two seeps, could be eliminated. Since the natural drainage channels and wetlands are considered "Waters of the United States" or "jurisdictional waters", their elimination would constitute a significant, potentially unavoidable impact. This is discussed further below.

Vegetation and Wildlife

Three biotic habitats occur on the site. These include mixed coast live oak-bay woodland (21.33 acres), serpentine bunchgrass (3.51 acres), and freshwater wetland/aquatic (1.19 acres). Five special-status plant species have been observed on the project site, all growing within the serpentine bunchgrass habitat, located on the higher elevations of Lots 3, 6 and 7. Two of these plants, the Marin dwarf flax and the Tiburon Indian paintbrush, have State and Federal listing status (i.e. threatened, endangered). Although there would be no direct permanent impact from project development on the site’s serpentine bunchgrass habitat, it is likely that there would be indirect impacts through incidental use by individual lot owners once homes are occupied. In addition, installation of new waterlines could temporarily affect habitat for special-status plants in the serpentine areas due to trenching and grading associated with construction of these facilities. This impact can be mitigated to a less than significant level through the implementation of mitigation measures recommended by the DEIR.

Project implementation would impact a minimum of 2.43 acres of mixed coast live oak-bay woodland, resulting in the removal of 314 trees. In addition, trenching and grading associated with a proposed new waterline could impact up to an additional 1.26 acres of mixed live oak-bay woodland, resulting in the loss of additional trees. Mitigation measures recommended in the DEIR would lessen the impact, but depending on the number of trees removed, may not reduce it to a less-than-significant level. Therefore, this impact may be considered significant and unavoidable.

There are at least five seasonal drainages, a spring, and two seeps located on the project site. These wetland areas provide habitat for a variety of animals. The EIR biologists surveyed the site and vicinity for the presence of the California red-legged frog (CRLF). No CRLF’s have been detected on or ever reported from the Tiburon Glen site or adjacent lands. The project site is approximately two miles northwest of Keil Pond, the only known breeding habitat for CRLF’s on the Tiburon Peninsula. Considerable development exists between the site and Keil Pond; therefore, it is unlikely that CRLF’s occur on the Tiburon Glen project site.

Visual and Aesthetic Quality

Photo simulations were prepared to illustrate development at build-out of the project, as seen from selected viewpoints, mostly along Paradise Drive. The simulations are conceptual representations of homes that could be constructed on the site, based on the PDP site plan, proposed building envelopes, maximum building heights and floor area, and conceptual designs submitted by the applicant. Because future lot owners would design and build their homes, the simulations are not intended to represent what the project would actually look like, but rather to illustrate visual changes from development of the site. The project’s visual impacts range from minimal to significant, depending on the viewpoint, the sensitivity of the view and the visual dominance of the proposed development. The DEIR recommends mitigation measures that would reduce most of the visual impacts to less than significant levels. However, the visual impacts from two vantage points (Viewpoints 2 and 3) and the loss of the mixed coast live oak-bay woodland are considered significant and unavoidable, as discussed further below.

Transportation and Circulation

The traffic study prepared for this project estimates that a total of 80 trips per day would be generated by the proposed project. This projected increase in traffic would not have a significant impact on any nearby streets, and all intersections in the vicinity of the project site would continue to operate at level of service (LOS) C or better. However, under cumulative-plus-Project conditions, the signalized Trestle Glen/Tiburon Boulevard intersection would operate unacceptably at LOS E during the weekday AM peak hour. A recommended mitigation measure would require the applicant to pay a traffic mitigation fee that would go toward the improvements planned for this intersection, which include adding a second westbound through lane on Tiburon Boulevard, extending east toward Stewart Drive.

The DEIR traffic analysis indicates that there would be an inadequate line of sight for vehicles turning left out of Development Area No. 2 (Roadway C serving Lots 7 and 8) onto Paradise Drive. The DEIR concludes that this impact can be mitigated to less-than-significant by the removal of one tree and trimming of intervening roadside vegetation in order to increase the sight lines to the south.

Other traffic related impacts identified in the DEIR include the lack of adequate on-site parking, construction traffic, steepness of proposed access roads, and the cumulative impact of additional project traffic on pedestrian and bicycle use of Paradise Drive. The DEIR recommends mitigation measures that would reduce these impacts to less-than-significant levels.

Air Quality

Construction activities, including grading of serpentine soils containing naturally occurring asbestos, would generate dust and possibly release asbestos into the air. The DEIR concludes that this impact could be reduced to a less-than-significant level by implementing enhanced dust suppression measures during construction. The number of traffic trips generated by the project in the future would not be large enough to result in a measurable deterioration of local air quality.

Noise

Construction noise associated with the project could affect nearby residences. The DEIR recommends mitigation measures that would reduce these impacts to less than significant levels.

Public Services and Utilities

The Marin Municipal Water District (MMWD) would supply water to the project site. The applicant proposes to connect to an existing eight-inch water line that serves the Norman Estates neighborhood. This eight-inch line is connected to the Mount Tiburon water tank, located southwest of the project site. According to MMWD, the water tank would be adequate for both domestic use and fire flow requirements. However, MMWD has indicated that the existing emergency storage capacity of the Mount Tiburon tank is deficient. Emergency storage is used for fire fighting and for domestic use in the event that regular supply is interrupted by a failure in the supply system. MMWD is planning to increase the Mount Tiburon tank’s emergency storage capacity in the future, but has not yet developed any specific improvement plans. The DEIR recommends a mitigation measure that would require the applicant to pay storage charges assessed by MMWD to offset the cost of these future planned improvements.

Sanitary District #5 would provide sanitary sewer service to the project. The District’s Paradise Cove treatment plant, located at 3700 Paradise Drive, would serve the project. The DEIR indicates that, according to the Sanitary District, the Paradise Cove treatment plant is anticipated to reach 80% of its capacity prior to the anticipated completion date of this project. Applications for connection to the treatment plant submitted after the plant has reached the 80% threshold will be required to participate in the funding of a comprehensive wastewater treatment plan, which is a recommended mitigation measure in the DEIR. Furthermore, the project could not proceed unless and until the availability of adequate wastewater treatment capacity is verified by the District, and if necessary the Regional Water Quality Control Board (RWQCB), and an "ability to serve" letter is issued.

School capacity and police services are adequate to serve the proposed project. The Tiburon Fire Protection District can supply adequate fire protection services to the project, with implementation of a variety of mitigation measures identified in the DEIR that would improve the ability of the fire district to successfully fight fires on the property.

Cultural Resources

While no discernable impacts to archaeological resources are anticipated and no human remains are expected to be present on the site, the possibility cannot be precluded that prehistoric cultural deposits and features are present below the ground surface and could be damaged during grading/construction activities. Mitigation measures are identified in the DEIR that would be implemented in the event that any artifacts or human remains are discovered on the site.

Significant Unavoidable Impacts

-significant level through mitigation measures identified in the DEIR. Most are secondary impacts that would result from grading that may be necessary for landslide repair. The type and extent of stabilization required for landslide repair would depend on the outcome of additional geologic investigation and the mitigation strategy that is determined to be most appropriate in order to implement the Town’s landslide repair policy. Depending on the extent of excavation that is required for landslide repair, a number of secondary impacts to site resources could result from project implementation. It is premature to describe and quantify the precise nature of those impacts because the full magnitude of landslide stabilization efforts and the techniques that would be used are not currently known.

The significant unavoidable impacts are summarized below:

Impacts on Drainageways and Disturbance to Jurisdictional Waters (Impacts 5.2-4 and 5.3-5) - There are at least five seasonal drainages and two seeps located on the project site. Natural drainage channels and wetlands are considered "Waters of the United States" and are referred to as "jurisdictional waters." All activities that involve the discharge of fill into jurisdictional waters are subject to the permit requirements of the U. S. Army Corps of Engineers (Corps). Development of the proposed roads for Lots 2 and 8, and the building envelope for Lot 7 would result in the loss of 0.11 acres of seasonal wetlands. In addition, the secondary effects of grading for landslide repair could affect 0.5 acres or more of the 1.19 acres of seasonal wetlands estimated to be on the site. Mitigation Measure 5.3-5a would require that a Wetlands Delineations Map be prepared that depicts all of the areas potentially under the jurisdiction of the Corps, to be verified by the Corps. Mitigation Measure 5.3-5b requires that the project be redesigned to avoid impacts to areas identified on the Corps verified map. If avoidance if not possible, and the amount of wetlands impacted is substantial, a Wetland Restoration Plan would be required as called for in Mitigation Measure 5.3-5c. However, landslide repair could affect all site drainages, thereby eliminating all jurisdictional waters on-site, leaving no opportunities for on-site restoration and making it difficult to find sufficient areas off-site for replacement wetlands. If this were the case, impacts to jurisdictional waters could remain significant and unavoidable.

Loss of Mixed Coast Live Oak-Bay Woodland (Impact 5.3-4) - The loss of mixed coast live oak-bay woodland described above could be reduced to a less-than-significant level if the project could be redesigned in a way that would result in the removal of 150 or fewer trees (Mitigation Measure 5.3-4a) and a Tree Protection and Forest Enhancement Plan were implemented (Mitigation Measure 5.3-4b). If an avoidance plan could not be implemented (Mitigation Measure 5.3-4a) other identified mitigation measures would lessen the impact, but would not reduce it to a less-than-significant level. Thus, the impact would be a significant unavoidable impact.

Disturbance of Serpentine Bunch Grass (Impact 5.1-3) - Though project implementation would generally avoid direct impacts to the serpentine bunch grass, trenching necessary for geotechnical investigation or landslide repair could be of such magnitude that the additional disturbance would represent a significant unavoidable impact to the serpentine bunchgrass and to the special-status species that may occur within this habitat. Even though this impact would be temporary, the sheer magnitude of having to restore nearly the entire serpentine bunchgrass habitat while protecting any special status species that exist within this habitat may become impracticable or infeasible.

Visual Impact Looking East from Paradise Drive-Viewpoint 2 (Impact 5.4-2) - Exhibits 5.4-6 and 5.4-7 of the DEIR show Lots 3, 4, 5 and 6 both before and after development. The DEIR concludes that the proposed structures’ texture and angular form would contrast significantly with the woodland backdrop and with the existing view’s uninterrupted wooded slopes. Even with implementation of mitigation measures that would lessen visual and aesthetic impacts of the project (Mitigation Measure 5.4-1), the project would result in a significant unavoidable impact from this vantage point.

Visual Impact Looking West from Paradise Drive - Viewpoint 3 (Impact 5.4-3) - Exhibits 5.4-8 and 5.4-9 of the DEIR show Lots 7 and 8 both before and after development. The DEIR concludes that the two structures’ form, texture and color would likely contrast with the uniform woodland backdrop, which would only partially screen the proposed buildings. The roof of a 30-foot high structure on each of the lots would be expected to interrupt the profile of the tree canopy, although structures themselves would have woodland backdrops. Even with implementation of mitigation measures that would lessen visual and aesthetic impacts of the project (Mitigation Measure 5.4-1), the project would result in a significant unavoidable impact from this vantage point.

Visual Impact of Landslide Repair/Loss of Coast Live Oak Forest (Impact 5.4-8) Compliance with the Town’s landslide repair policy could result in substantial landslide excavation that could require the removal of all vegetation in the unstable areas. In the coast live oak-bay woodlands, tree removal would result in a long-term negative visual impact from the loss of that unique visual resource. Implementation of mitigation measures to reduce and compensate for impacts on the mixed coast live oak-bay woodland (Mitigation Measure 5.3-4c) would lessen the impact over time. However, new replacement trees would take many years to mature, and the landscape would be noticeably altered for years after project development. As a result, it would remain a significant unavoidable impact.

Project Alternatives

The DEIR assesses four alternatives to the proposed project:

No Development Alternative (required by CEQA)

Three-Lot Alternative

Two-Lot Alternative

Public Open Space Alternative

The DEIR concludes that the Public Open Space Alternative is the environmentally superior alternative because it would preclude any future development proposals. However, this alternative would require acquisition by a public agency. The DEIR analysis concludes that the Two-Lot Alternative is the environmentally superior "development alternative" because it would involve the least disturbance of the site.

COMMENTS ON THE DRAFT EIR

As of the writing of this report (October 3, 2002), comment letters regarding the DEIR have been received from nine (9) agencies or individuals. These comment letters are attached as Exhibits 2 through 10 of this report. Letters received subsequent to the completion of this report will be distributed as Late Mail to the Planning Commission.

FUTURE ACTIONS REQUIRED

The Commission will need to hold a public hearing, following the close of the comment period on October 14, 2002, at which it will determine whether or not the DEIR has been prepared in conformance with CEQA. At that hearing, the Commission may either:

1. Accept the DEIR as being prepared in conformance with CEQA and the Town's local CEQA Guidelines, and direct the consultant to respond to comments; or

2. Find that the DEIR was not prepared in conformance with CEQA and continue the matter pending receipt of additional information necessary to achieve such conformance.

Town Staff and the EIR consultants will review the comments received during the comment period and will prepare recommendations for the Planning Commission to consider at that public hearing. The precise date of that meeting has not yet been determined, and may be affected by a court decision, tentatively scheduled for October 11, 2002, on a pending CEQA lawsuit against the Town that was filed by the property owner. Staff will keep the Commission apprised of any scheduling matters affected by the court decision.

RECOMMENDATION

Staff recommends that the Planning Commission hear the Staff presentation, and then receive comments on the DEIR from all interested persons.

EXHIBITS

Project Drawings (14 sheets, 11" X 17" format).

Letter from Norman Traeger received 9/26/2002.

Letter from Harvey Poppel received 10/2/2002.

Letter from Annelies Atchley received 10/2/2002.

Letter from Marin Municipal Water District received 10/2/2002.

Letter from Hans Roenau received 10/2/2002.

Letter from Bob Benbow received 10/2/2002.

Letter from Grassetti Environmental Consulting received 10/2/2002.

Letter from Randy Greenberg received 10/3/2002.

Letter from Tiburon Fire Protection District received 10/3/2002.

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