TO: NAPA COUNTY ZONING ADMINISTRATOR
FROM: Enrique Torres, Planner II
REPORT BY: Enrique Torres, Planner II
SUBJECT: Yount Mill Road Residence Viewshed Protection Program (P25-00015-VIEW)
RECOMMENDATION
title
DAVID DEL DOTTO AND BOB MUELLER / YOUNT MILL ROAD RESIDENCE / VIEWSHED PROTECTION PROGRAM; P25-00015-VIEW
CEQA Status: Consideration and possible adoption of a Categorical Exemption Class 3 and Class 4: It has been determined that this type of project does not have a significant effect on the environment and is exempt from the California Environmental Quality Act. See Section 15303 (Class 3 New Construction or Conversion of Small Structures) and Section 15304 (Class 4 Minor Alteration to Land), which may be found in the guidelines for the implementation of the California Environmental Quality Act at 14 CCR §15303 and §15304. The project site is not included on a list of hazardous materials compiled pursuant to Government Code Section 65962.5
Request: Approval of a Viewshed Protection Program application for the construction of a residential project within view of Highway 29, a County designated viewshed road, and on slopes exceeding 15%. The project consists of a 7,450 square-foot main residence, an underground pool, 816 square-foot accessory dwelling unit, 814 square-foot detached garage, and landscaping plan. The project is located on an approximately 14.4-acre parcel within the Agricultural Preserve (AP) Zoning District and has a General Plan designation of Agriculture Resource (AR). Yount Mill, Napa, CA 94558. APN: 031-120-042-000.
Staff Recommendation: Adopt Categorical Exemptions and approve Viewshed Protection Program application No. P25-00015-VIEW, as conditioned.
Staff Contact: Enrique Torres, Planner II, enrique.torres@countyofnapa.org, (707) 253-4307
Property Owner: Dave Del Dotto, 540 Technology Way, Napa, CA 94558, (707) 480-0176
Applicant Representative Contact: Bob Mueller, 731 S Highway 101 Suite 12, Solano Beach, CA 92075, Napa, CA 94558, bmueller@rmcigroup.com, (858) 775-0701
Applicant Contact: David Cruz, 731 S Highway 101 Suite 12, Solano Beach, CA 92075, dcruz@rmcigroup.com
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EXECUTIVE SUMMARY
Proposed Actions:
That the Zoning Administrator:
1. Adopt the Categorical Exemptions based on recommended Findings 1-3 in Attachment A; and
2. Approve the Viewshed Protection Program request (P25-00015-VIEW) based on recommended Findings 4-10 in Attachment A, and subject to the recommended Conditions of Approval in Attachment B.
Discussion:
The proposed project consists of a request to approve a Viewshed Protection Program application to construct a 7,450 square-foot main residence, an underground pool, 814 square-foot detached garage, and an 816 square-foot accessory dwelling unit, which lies 206 feet below a minor ridgeline. The project site is currently vacant and undeveloped, with all site improvements, residential and accessory structures being considered under File No. P25-00015-VIEW.
The main residence, underground pool, garage, and accessory dwelling unit will be constructed on the base of a hillside visible from Highway 29 which is identified as a designated county public road in the Napa County General Plan and Chapter 18.106 (Viewshed Protection Program) of the Napa County Code (NCC). Therefore, the proposed residential and accessory structures are subject to review for compliance with the Viewshed Protection Program prior to issuance of any associated development permits. Given that the project would result in a combined total of more than 4,000 square feet of floor area on the property for only the main residence (7,450 square feet proposed), the project does not meet the criteria for administrative review under NCC §18.106.040 and has been scheduled for review by the Zoning Administrator.
As proposed, the project has been designed in substantial conformance with the County’s viewshed protection manual because it would limit the construction on a portion of the project parcel which has naturally lower slopes, resulting in the minimization of grading on steep slopes, and the utilization of the proposed landscaping plans as a means of substantially screening the proposed structures from Highway 29 primarily by proposed vegetation.
Staff believe all findings can be made in support of the project and recommends approval subject to the recommended conditions of approval.
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: Consideration and possible adoption of a Categorical Exemption Class 3 and 4. It has been determined that this type of project does not have a significant effect on the environment and is exempt from the California Environmental Quality Act. See Section §15303 (Class 3 New Construction or Conversion of Small Structures) and §15304 (Class 4 Minor Alterations to Land), which may be found in the guidelines for the implementation of the California Environmental Quality Act at 14 CCR §15303 and §15304. The project site is not included on a list of hazardous materials compiled pursuant to Government Code Section 65962.
BACKGROUND AND DISCUSSION
Owner: Dave Del Dotto, 540 Technology Way, Napa, CA 94558, (707) 480-0176
Applicant: Bob Mueller, 731 S Highway 101 Suite 12, Solano Beach, CA 92075, Napa, CA 94558, bmueller@rmcigroup.com, (858) 775-0701
Representative: David Cruz, 731 S Highway 101 Suite 12, Solano Beach, CA 92075, dcruz@rmcigroup.com
Zoning: Agricultural Preserve (AP)
General Plan Designation: Agricultural Resources (AR)
Property Area: 14.4 acres
Application Filed: January 17, 2025
Application Deemed Complete: November 7, 2025
Surrounding Uses:
North - AP zoning with AR General Plan Designation - Developed with Residence, Winery, Vineyard, Oak Woodland, Coniferous Forrest.
East - AP zoning with AR General Plan Designation - Developed with Residence, Vineyard, Oak Woodland, Coniferous Forrest.
South - AP zoning with AR General Plan Designation - Developed with Residence, Vineyard, Oak Woodland, Undeveloped Land.
West - AP zoning with AR General Plan Designation - Developed with Residence, Winery, Vineyard
Existing Development: The parcel is an undeveloped site which contains one groundwater well, a gate at site access (Gate Easement 2024-0018911), and is vegetated with upland annual grasslands & forbs formation, California Bay Madrone, and Coast Live Oak (Black Oak Big Leaf Maple).
Proposed Development: The proposed development includes the construction of a 7,450 square-foot main residence, an underground pool, 814 square-foot detached garage, and an 816 square-foot accessory dwelling unit. With the project site being located on slopes over 15%, located 206 feet below a minor ridgeline, and located near a county viewshed road Highway 29, the proposed residential project is subject to review and approval by the Zoning Administrator. By limiting the construction on a portion of the project parcel which has naturally lower slopes the project shall minimize grading and alteration of natural landforms and topography.
Parcel History:
On December 26, 2024, a Lot Line Adjustment (Doc No. 2024-0018905 through 2024-0018914) was processed, the subject property decreased in size from 14.7 acres to 14.4 acres. On February 28, 2025, the property was sold with the rights to existing well (WCR No. e0290239), with the intent to develop a residence on the project parcel. The project parcel is currently vacant and undeveloped, with site improvements proposed to develop a residence. The site’s access is shared with a gate easement (2024-0018911), along the northwestern property line. The proposed parcel’s single-family residence, garage, and accessory dwelling unit will be located on the flattest portion of the property that is approximately 130 to 420 feet above mean sea level (amsl).
The proposed residence site is located on an undeveloped portion of the base of a hillside with slopes between ten and twenty-eight percent slopes. By limiting the construction on a portion of the project parcel which has naturally lower slopes the project shall minimize grading and alteration of natural landforms and topography. According to County of Napa Environmental Mapping (GIS Geology layer) soil types include Boomer-Forward-Felta Complex and Forward Silt Loam on the project site. According to County of Napa Environmental Mapping (GIS Vegetation layer) the property is identified as upland annual grasslands & forbs formation, California Bay Madrone, and Coast Live Oak (Black Oak Big Leaf Maple). The proposed project site is mapped as annual grasslands & forbs formation. Land uses in the area are dominated by large lot residential properties, wineries, and vineyards. There are several off-site residences that measure between approximately 300-1100 feet from the proposed residence.
Code Compliance History:
There are no records of prior code violations related to the project site.
Viewshed Protection Program: - Napa County Code Chapter 18.106 establishes:
18.106.030(A): Applicability-New and Expanded Structures. No building permit, erosion control plan for structural development, grading or other administrative permit shall be issued by any county staff, agency or department for any new structure or improvement to an existing structure if the structure is located on a slope of fifteen percent or more as defined in Section 18.106.020 or if the structure is located on any minor or major ridgeline as defined in Section 18.106.020 except as specifically provided for herein. The ordinance codified in this section shall apply to all new structures located on slopes of fifteen percent or more or located on a minor or major ridgeline. In the event of a conflict among the regulations in this chapter and those elsewhere in this code, the regulations in this chapter shall prevail. The provisions of this chapter shall also apply to projects undertaken by public agencies and special districts except for the maintenance of existing county public roads within existing rights-of-way.
The proposed project is located on slopes greater than 15% and to determine if the project would be visible from Highway 29, the applicant provided a visibility analysis. The analysis included and identified viewshed sightlines from Highway 29 on a vicinity map, along with a photograph to document the viewshed sightline. The applicant has also incorporated numerous design features into the project to protect the viewshed resources by including a landscaping plan which projects for a total of 51% screening of the proposed project, utilizing non-reflective windows and glass guardrails, along with locating the proposed development in such a way that limits the construction on a portion of the project parcel which has naturally lower slopes the project shall minimize grading and alteration of natural landforms and topography.
To qualify for administrative review under the Viewshed Protection Program per NCC §18.106.040, a project must meet all listed design and siting conditions including a 4,000 square foot limit on combined total maximum floor area. Given that the project includes the construction of a 7,450 square-foot main residence, an underground pool, 814 square-foot attached garage, and an 816 square-foot accessory dwelling unit, the total floor area for the project exceeds the requirements for administrative process, requiring Zoning Administrator approval as applied through NCC §18.106.050, with findings for approval that support these requirements found in Attachment A.
Discussion Points:
Setting - Access to the project site is located off Yount Mill Road, approximately 1.25 miles southwest of the northwestern boundary of the City of Yountville, 0.3 miles east along Yount Mill Road from the intersection of Highway 29 and Yount Mill Road. The project includes one (1) parcel, APN 031-120-042-000, approximately 14.4 acres in size and currently undeveloped. The parcel has an access entry point from Yount Mill Road. The site’s access is shared with a gate easement (2024-0018911), along the western property line. The proposed parcel’s single-family residence, underground pool, garage, and accessory dwelling unit will be located on the flattest portion of the property that is approximately 130 to 420 feet above mean sea level (amsl). By limiting the construction on a portion of the project parcel which has naturally lower slopes the project shall minimize grading and alteration of natural landforms and topography.
According to the Napa County GIS Map (Biological, Geology & Soils, Hazards, Hydrology Layer), the proposed development site is located on a portion of the base of a hillside with slopes between ten (10) and twenty-eight (28) percent slopes. Soil types include Boomer-Forward-Felta complex and Forward Silt Loam on the project site. The project site is located in an area with an identified landslide creep, otherwise referred to as a creep-prone soil by Bauer Associates, Inc. in the project specific Geotechnical Investigation. A creep-prone soil was observed uphill of the planned development area, it is anticipated from past landsliding and erosion, to have occurred further uphill to the west and the materials transported downhill as intermittent debris flows. It is planned to excavate foundations through natural soils and/or engineered fill to bear into bedrock per the recommendations of the report.
According to County of Napa Environmental Mapping (GIS Vegetation layer) the property is identified as upland annual grasslands & forbs formation, California Bay Madrone, and Coast Live Oak (Black Oak Big Leaf Maple). The proposed project site is mapped as annual grasslands & forbs formation. Land use in the area is dominated by large lot residential properties, wineries, and vineyards. There are several off-site residences that measure between approximately 300-1100 feet from the proposed residence.
Tree/Vegetation Retention and Visual Screening - The vegetation retention requirements of NCC Section 18.108.020 (Conservation Regulations - General Provisions) are not applicable to this project as it is located outside of an Agricultural Watershed and located in the Agricultural Preserve. However, the applicant acknowledges the removal of individual oak trees and, while not applicable, is satisfying the minimum 2:1 replacement ratio set forth in Conservation Policy 24(c) of the Napa County General Plan.
The project relies on visual screening attained by utilizing a professionally prepared landscaping plan. The landscaping consists of fourteen (14) replacement 15-gallon Oak trees, five (5) 24” box non-fruiting olive tree, eleven (11) 36” box non-fruiting olive tree, and eight (8) box hedges +36” above finished grade. The landscaping, associated with the Yount Mill Road Residence Viewshed will provide some screening of the residences and associated structures and ensure compliance with defensible space requirements.
Access Improvements - The applicant proposes access improvements to the parcel’s existing driveway from Yount Mill Road. The driveway would include a gate easement (2024-0018911), tractor access easement (2025-0002931), and access easement (29095-0002931) and reconfiguration of existing driveway and would be constructed consistent with Napa County Road and Street Standards.
Ground Water - On August 26, 2025, EBA Engineering prepared a parcel-specific Tier 1, 2, & 3 Water Availability Analysis (WAA) for the 14.4-acre residential project. In the tier 1 WAA, EBA analyzed the project site groundwater budget by comparing estimated inflows and outflows from the fractured-rock aquifer complex. The recharge rate was calculated by using each of the calculated values in the groundwater recharge equation and the corresponding estimated volume of water available, resulting in groundwater recharge on the project site at approximately 9.66 AFY during average precipitation years. EBA estimated the volume of water available for groundwater recharge to be approximately 27% of the annual precipitation volume of 35.54 AFY. Residential (main dwelling, in-ground pool, accessory dwelling unit, detached garage) water demand was estimated at 1.3 AF/y r while the landscaping (oak trees, olive trees) were estimated to require 0.32 AF/yr. Considering the property’s groundwater recharge rate, and proposed water usage, which include minimal landscaping, a main residence, in-ground pool, accessory dwelling unit, and detached garage; it can be assumed the project’s increase in water demand will not result in a potentially significant impact to groundwater resources. The property is expected to remain below the annual rate of recharge.
In the Tier 2 WAA, an evaluation was conducted in order to assess the potential drawdown in the existing well within 500 feet. Utilizing two methods, the Tier 2 WAA screened within the same aquifer as the project well. The results prove that well #2 (project parcel serving well) which is 260 feet to the nearest well (well #1) results in an estimated drawdown at less than one foot, under the maximum of ten feet or less.
In the Tier 3 WAA, the analysis requires that a groundwater/surface water interaction evaluation be conducted for project wells located within 1,500 feet of a Significant Stream. A mapped Significant Stream, Lincoln Creek, is located approximately 1,345 feet to the north of Well #2, at its closest point. Given Lincoln Creek is shallow in depth and is cut into the shallower layers of sedimentary deposits that overly the Sonoma Volcanic aquifer, it is EBA’s opinion that this stream is a losing stream and not recharged by shallow groundwater. This information suggests that the hydraulic connectivity between the underlying deeper aquifer system and Lincoln Creek is low to non-existent, and groundwater that will be pumped from Well #2 completed primarily in the Sonoma Volcanics will not be connected to Lincoln Creek. It is EBA’s opinion that pumping from Well #2 will not contribute to streamflow depletion in the nearby Significant Stream (Lincoln Creek).
The public trust doctrine requires the state and its legal subdivisions to “consider,” give “due regard,” and “take the public trust into account” when considering actions that may adversely affect a navigable waterway. (Environmental Law Foundation v. State Water Resources Control Bd. (2018) 26 Cal.App.5th 844, 853-54; San Francisco Baykeeper, Inc. v. State Lands Com. (2015) 242 Cal.App.4th 202.) There is no “procedural matrix” governing how an agency should consider public trust uses. (Citizens for East Shore Parks v. State Lands Com. (2011) 202 Cal.App.4th 549, 576.) Rather, the level of analysis “begins and ends with whether the challenged activity harms a navigable waterway and thereby violates the public trust.” (Environmental Law Foundation, 26 Cal.App.5th at p. 403.). As demonstrated in the Environmental Law Foundation v. State Water Resources Control Board Third District Appellate Court Case, that arose in the context of a lawsuit over Siskiyou County’s obligation in administering groundwater well permits and management program with respect to Scott River, a navigable waterway (considered a public trust resource), the court affirmed that the public trust doctrine is relevant to extractions of groundwater that adversely impact a navigable waterway and that Counties are obligated to consider the doctrine, irrespective of the enactment of the Sustainable Groundwater Management Act (SGMA). As disclosed and assessed in the WAA, the County concludes that no harm to (or less-than-significant impacts on) public trust resources would result from the proposed project.
Noise - The proposed project would result in a temporary increase in noise levels during grading and construction activities. However, noise generated during by construction activities would be limited to daylight hours and the use of properly muffled vehicles. A single-family residence and accessory dwelling unit are not land uses that typically exceed County noise standards.
Public Comments - At the time of staff report preparation no public comments have been received.
Decision Making Options:
As noted in the Executive Summary Section above, staff is recommending the Zoning Administrator approve the project as summarized in Option 1, subject to the recommended Findings and Conditions of Approval in Attachment A and B, respectively. Decision making options include the following:
Option 1 - Approve Applicant's Proposal (Staff Recommendation)
Disposition - This action will result in approval of the Viewshed Protection Program application for the Yount Mill Road Residence. Staff recommend this option as the request is consistent with all other aspects of the Zoning Ordinance including allowable use, development standards and required setbacks, as well as applicable General Plan policies and other County regulations. Furthermore, there will be no significant environmental impacts resulting from the main residence, detached garage, and accessory dwelling unit, as discussed in the Categorical Exemption as presented in the Recommended Findings (Attachment A).
Action Required - Follow the proposed action listed in the Executive Summary. If conditions of approval are to be amended, specify conditions to be amended at time motion is made.
Option 2 - Modify the Applicant’s Proposal
Disposition - In the event that the Zoning Administrator finds the project needs revision or more information is required to determine if the Findings for approving a Viewshed Protection Program application can be made, the Zoning Administrator would move to continue the item to a later date to allow the applicant time to consider revisions to the project.
Action Required - Make recommendations for an amended scope and/or applicable conditions of approval. The item will need to be continued to a future date if significant revisions to the project scope and recommended conditions of approval are desired.
Option 3 - Deny Applicant's Proposal
Disposition - In the event the Zoning Administrator determines that the project does not, or cannot, meet the required findings for approving a Viewshed Protection Program application the Zoning Administrator should articulate what aspects of the project are in conflict with the required findings. State Law requires the Zoning Administrator to adopt findings, based on the General Plan and County Code, setting forth why the proposed project is not being approved.
Action Required - Take tentative action to deny the project and remand the matter to staff for preparation of findings for denial and continue the item to a date specific for final action by the Zoning Administrator.
Option 4 - Continuance Option
The Zoning Administrator may continue an item to a future hearing date at its own discretion.
SUPPORTING DOCUMENTS
SUPPORTING DOCUMENTS
A. Recommended Findings
B. Recommended Conditions of Approval & Agency Memorandums
C. CEQA Exemption Memorandum
D. Viewshed Application
E. Water Availability Analysis
F. Geotechnical Investigation
G. Preliminary Stormwater Control Plan
H. Graphics