DESIGN REVIEW BOARD STAFF REPORT September 9, 2021 Agenda Item No. 4.3 Case No: Design Review 21-9501 Coastal Development Permit 21-9500 Variance 2 1-9502 Categorical Exemption Project Location: 741 Summit Drive APN: 644-252-02 Applicant: Gregg Abel, Designer (949) 497-3442 gregg greggabel.com Property Owner: Nocella Residence Prepared By: Community Development Department Christian Dominguez Associate Planner (949) 497-0745 cdominguez~lagunabeachcity.net REQUESTED ACTION: The applicant requests design review for modifications to a prior approval in the R-1 (Residential Low Density) zone. Modifications include a new 589 square-foot accessory dwelling unit (ADU), elevated decks (337 square feet), grading, retaining walls, and pool and spa. A coastal development permit is requested for the ADU and a variance is requested to exceed the maximum allowed 16-foot height for an ADU [LBMC 25.17.030(G) and Government Code Section 65852.2(c)(2)(C)j. RECOMMENDATION: Adopt Resolution No. 21-9501, approving Design Review 21-9501, Coastal Development Permit 21-9500, and Variance 21-9502, for the proposed modifications and ADU, subject to the attached Exhibits ‘A’, ‘B’ and ‘C’; and adopt a Categorical Exemption pursuant to the California Environmental Quality Act (CEQA). ATTACHMENTS 1) Public Correspondence 2) Preliminary Hydrology Report- 2 1 21 (linked to online agenda) 3) Draft Resolution 4) Exhibit ‘A’: General Plan Goals and Policies Local Coastal Program Goals and Policies 5) Exhibit ‘B’: Conditions of Approval 6) Exhibit ‘C’: Proposed Plans
Transcript
DESIGN REVIEW BOARD STAFF REPORT
September 9, 2021
Agenda Item No. 4.3
Case No: Design Review 21-9501Coastal Development Permit 21-9500Variance 2 1-9502Categorical Exemption
Prepared By: Community Development DepartmentChristian Dominguez Associate Planner(949) 497-0745 cdominguez~lagunabeachcity.net
REQUESTED ACTION: The applicant requests design review for modifications to a prior approval inthe R-1 (Residential Low Density) zone. Modifications include a new 589 square-foot accessory dwellingunit (ADU), elevated decks (337 square feet), grading, retaining walls, and pool and spa. A coastaldevelopment permit is requested for the ADU and a variance is requested to exceed the maximum allowed16-foot height for an ADU [LBMC 25.17.030(G) and Government Code Section 65852.2(c)(2)(C)j.
RECOMMENDATION: Adopt Resolution No. 21-9501, approving Design Review 21-9501, CoastalDevelopment Permit 21-9500, and Variance 21-9502, for the proposed modifications and ADU, subject tothe attached Exhibits ‘A’, ‘B’ and ‘C’; and adopt a Categorical Exemption pursuant to the CaliforniaEnvironmental Quality Act (CEQA).
ATTACHMENTS1) Public Correspondence2) Preliminary Hydrology Report- 2 1 21 (linked to online agenda)3) Draft Resolution4) Exhibit ‘A’: General Plan Goals and Policies
Local Coastal Program Goals and Policies5) Exhibit ‘B’: Conditions of Approval6) Exhibit ‘C’: Proposed Plans
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PROPERTY AERIAL PHOTO
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PROPERTY INFORMATIONLand Use Designation Village Low Density (3-7 DU/AC)
Zoning Designation R-1 Residential Low DensityEnvironmentally Sensitive Areas Mapped Watercourse & Coastal Zone Appealable.Site Constraints Very High Fire Hazard Severity Zone & Drainange Course.
• Single-family residence and detached garage.• On August 4, 1977, the Board of Adjustment approved Design
Review 77-150 and Variance 2879 to construct additionswithout bringing non-conforming conditions intoconformance.
• On June 16, 1983, the Board of Adjustment approved DesignReview 83-107 to construct an elevated deck and spa.
• On December 17, 1991, the City Council adopted ResolutionNo. 92.006 to vacate, close and abandon a portion of SummitWay located north of the subject property
Existin: Site Im.rovements
Prior Approvals
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zbNiNG REVIEWThe proposed project complies with applicable zoning standards and guidelines as shown in the summaryt~klc below, except for building height, which is discussed under the Variance section below.DãelopineO€Standard Reguik~éd~- . ~EVisting~.. ~Ei’opósed Conipliès?Height for Accessory Dwelling Unit(Lowest grade to top of roof) 16’-O” N/A 17’-7” NoLandscape Open Space 35% minimum 65% 55% Yes
PRQJECT DESCRIPTIONThe applicant proposes to construct an attached 589 square-foot accessory dwelling unit (ADU) at therear of the property on the home’s lower level. The ADU will consist of a living room, kitchen, twobedrooms, a bathroom, and 337 square feet of elevated deck area. A series of outdoor terraces areproposed for the rear yard to accommodate a new pool and spa with outdoor seating, exterior lighting,fire features, and outdoor barbegue.
DESIGN REVIEWPursuant to LBMC Section 25.05.040 1-1 , physical improvements and site developments subjectto design review shall be designed and located in a manner which best satisfies the intent and purposeof design review, the city’s village atmosphere and the design review criteria. These guidelinescomplement the zoning regulations by providing conceptual examples of potential design solutionsand design interpretations. The table below lists the guidelines and the proposed project’s applicabilityand compliance. The following project components require Design Review:
A. New elevated deck area (337B. Grading outside the buildingC. Retaining walls.D. Swimming pool and spa.
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Design.Review~Critena Consistency (Yes,?No; or1’N/AIf.Not-~AppIicabIe)Yes. The proposed project will not impact access in that theexisting two-car garage meets the City’s covered parkingrequirement for a residence less than 3,600 square feet in size. No
No. 1 I Access additional parking is required to be provided for the ADU due toits size (less than 800 square feet) and location within one-halfmile of public transit. For these reasons, this criterion has beenmet.Yes. The proposed outdoor terrace and swimming pool area is
.. . . divided into sections and terraced with the hillside at differentNo. 2 I Design Articulation elevations that helps reduce the appearance of mass. The
proposed deck provides visual interest for the lower level of the
square feet).footprint (181.1 cubic yards).
DESIGN REVIEW
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home and is consistent with existing decks on the middle andupper levels of the home. Therefore, this criterion has been met.Yes. The proposed project includes materials and finishes, suchas shingle siding and stone veneer, that are consistent with the
No. 3 I Design Integrity . .architectural style of the main residence. Therefore, this criterionhas been met.Yes. The subject property maintains a natural watercourse at therear as depicted on the aerial photo above. The proposedimprovements are located outside the required 25-footwatercourse setback. The applicant has prepared a preliminaryhydrology study (linked online) that provides recommendationsfor a residential storm drain system to collect surface runoff fromthe rear terraces for discharge into the adjacent watercourse. Thestudy concludes that the project will not have an adverse effecton the existing improvements or adjacent area. The City’sMunicipal Code requires temporary fencing to be provided duringconstruction to assure preservation of the watercourse and
No. 4 Environmental Context . .vegetative cover. Staff has included this as a condition ofapproval for the project.
Grading proposed for construction of the rear terraces includes107.3 cubic yards of cut and 73.8 cubic yards of fill for a netexport of 33.5 cubic yards. The proposed pool and spa require 77additional cubic yards of cut for a total net export of 1 1 1 cubicyards. The proposed grading is stepped to follow the property’snatural contours and the proposed net export is appropriateconsidering the scope of work. Therefore, this criterion has beenmet.Yes. The proposed project complies with the goals and policies
No. 5 [ General Plan Compliance . . . .of the General Plan as evidenced in the table in Exhibit AN/A. The property is not listed on the City’s Historic Register and
No. 6 Historic Preservation . . .there is no evidence of historicity.N/A. There is no previously approved landscape plan on-file forthe subject property and the proposed scope of work does notNo. 7 [ Landscaping . . .require submittal of a landscape plan. Therefore, this criteriondoes not apply.Yes. The proposed project includes new exterior lighting for therear terrace totaling 26 fixtures: 10 column lights, 12 step lights,and 4 wall sconce fixtures. The proposed column lights are
No. 8 [ Lighting and Glare lantern-style fixtures that may adversely affect nearby properties.A condition of approval has been included requiring all lights tobe hooded, fully shielded, and aimed downward to minimize lighttrespass. With this condition, this criterion has been met.
DESIGN REVIEW
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Yes. The surrounding neighborhood consists of large propertieswith an average lot area of over 10,000 square feet which allowsfor greater separation between residences and outdoor activity
No. 9 J Neighborhood Compatibility areas. The proposed improvements will be located at the rear ofthe property and approximately 80 feet from the nearest adjacentstructure which is compatible with the neighborhood’s pattern ofdevelopment. Therefore, this criterion has been met.
No. 10 I Pedestrian Orientation N/A. This criterion pertains to commercial development.Yes. The proposed project is not expected to cause privacy
No. 1 1 I Privacy impacts due to the size of the lot and distance from improvementson adjacent properties. Therefore, this criterion has been met.
No. 12 Public Art N/A. This criterion pertains to commercial development.No. 13 I Sign Quality N/A. This criterion pertains to commercial development.
Yes. The proposed pool and spa must comply with the City’s. . . water conservation requirements, including having a cover
No. 14 I Sustainabihty . . .installed when not in use, and not utilizing an automatic filldevice.Yes. A swimming pool and spa are proposed at the rear of theproperty that includes a slide as a play feature. The associated
. . mechanical equipment is proposed to be located in a vault belowNo. 15 I Swimming Pools, Spas and . . . .the new outdoor terrace which will minimize noise impacts toWater Features nearby properties. A five-foot wrought iron fence is proposed to
enclose the pool area for security. Therefore, this criterion hasbeen met.Yes. The proposed improvements are located at the rear of the lot
No. 16 I View Equity and are not expected to impact existing views from adjacentproperties. Therefore, this criterion has been met.
VARIANCEVariances may be granted only when, among other factors, there are special circumstances applicable to theproperty involved, including size, shape, topography, location and surroundings, that would cause the strictapplication of the zoning ordinance to deprive the property of the privileges enjoyed by other similarlysituated property in the vicinity and zone. The following project components require Variance:
1. To exceed the maximum allowed 16-foot height for an accessory dwelling unit by three feet [LBMC25.17.030(0)’ and Government Code Section 65852.2(c)(2)(C)2].
“An attached or detached second residential unit shall be limited to a single story and shall be no more than twelve feet aboveany point of the existing adjacent grade elevation, including chimneys, skylights and other rooftop equipment, and shall notexceed the highest elevation of the main residence. This height limitation shall not apply to the establishment of a secondresidential unit within an existing structure, provided that no exterior building additions, including new exterior above-gradestairs, are proposed. [.1” (LBMC 25.17.030(0); emphasis added.)2 “[~] (A) local agency shall not establish by ordinance any (requirements) [...] that does not permit [...1(a) unit that is at least
16 feet in height [...]“ (Gov. Code Section 65852.2(c)(2) and (c)(2)(C).)
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The Design Review Board may approve, approve in part, or conditionally approve a variance based uponmaking all of the following findings at a noticed public hearing:
(1) There are special circumstances applicable to the property involved, including size, shape,topography, location or surroundings which cause the strict application ofthe zoning ordinance todeprive such property ofprivileges enjoyed by other property in the vicinity and under identicalzoning classWcation.
Staff believes there are special circumstances applicable to the subject property which cause strictapplication of the zoning ordinance to deprive the property of privileges enjoyed by other propertiesin the vicinity and under identical zoning classification, in that the steep, down sloping topographyof the lot constrains the applicant’s ability to construct an ADU within the 16-foot maximumbuilding height limit allowed by-right and not require the variance. The proposed ADU is 16 feet 8inches in height measured from finished grade, and located below an existing floor of the dwelling,and complies with the 30-foot height limitation for the subject property in the R-1 Zone. In addition,a mapped watercourse is located at the rear of the property, which limits the buildable area of the lotwhere an ADU may be built without exceeding the 16-foot maximum height requirement. For thesereasons, staff believes this finding can be made.
(2) Such variance is necessaryfor the preservation and enjoyment ofa substantial property right oftheapplicant, which right is possessed by other property owners under like conditions in the samevicinity and zone.
The requested variance is necessary for the preservation of a substantial property right of theappIi~nt which right is possessed by other property owners under like conditions in the samevicinity and zone, in that construction of living space in underfloor areas is a common improvementfor other properties in the same vicinity and zone. Further, the proposed ADU will be located belowthe underlying 30-foot height limitation for the property, is consistent with the neighborhood pattern
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rrequested variance
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of development, and will not provide a special privilege. For these reasons, staff believes this findingcan be made.
(3) The granting of the variance will not be detrimental to the public health, safety, convenience andweffare or injurious to property or improvements in the vicinity in which the property is located.
The granting of the variance will not be detrimental to the public health, safety, convenience andwelfare or injurious to property or improvements in the vicinity in which the property is located inthat the proposed addition to establish the accessory dwelling unit meets all setback requirementsand will be structurally designed to meet public health and safety codes. Therefore, staff believesthis finding can be made.
(4) The granting ofsuch a variance will not be contrary to the objectives ofthe zoning ordinance or thegeneral plan.
The requested variance will not be contrary to the objectives of the zoning ordinance or the generalplan in that the intent of the R-l zone is for low-density, single-family residential areas, whichprovide a suitable environment for family life for residents and a quiet living environment.Additionally, the proposed development is compatible with the immediate residential neighborhoodwith respect to scale, mass and height. Finally, the establishment of the accessory dwelling unit willprovide for an additional housing unit and complies with the goals and policies of the HousingElement of the City’s General Plan. For these reasons, staff believes this finding can be made.
COASTAL DEVELOPMENT PERMITAccording to the 1993 Coastal Commission certified Post-LCP Certification Permit and Appeal Jurisdictionmap, the project site is located within the appealable area of the Coastal Zone. Pursuant to LBMC Chapter25.07, the proposed project requires a Coastal Development Permit (CDP) to ensure compliance with thecertified Local Coastal Program. The following criteria shall be incorporated into the review of allapplications for coastal development permits:CDP Criteria Consistency (Yes, No, or N/A if not applicable)No. 1 The proposed development will notencroach upon any existing physical accessway N/A. The proposed accessory dwelling unit is containedlegally utilized by the public or any proposed entirely upon a developed building site and does notpublic accessway identified in the adopted local maintain any physical accessways utilized by the public.coastal program land use plan.
Yes. The construction of the accessory dwelling unitNo. 2 I The proposed development will not will require temporary site best management practicesadversely affect marine resources, during construction activities to limit any potentialenvironmentally sensitive areas, or water runoff occurring from the site, and to preserve thearchaeological or paleontological resources. mapped watercourse located at the rear of the site.
Yes. The accessory dwelling unit is located on aNo. 3 I The proposed development will not developed residential lot and will not adversely affectadversely affect recreational or visitor-serving recreational or visitor-serving facilities or coastal scenicfacilities or coastal scenic resources. resources.
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COASTAL DEVELOPMENT PERMIT
September 9, 2021Page 8
No. 4 ] The proposed development will be sitedand designed to prevent adverse impacts toenvironmentally sensitive habitats and scenic N/A. The site is not located within an environmentallyresources located in adjacent parics and recreation sensitive habitat area or scenic resources located inareas and will provide adequate buffer areas to adjacent parks and recreation areas.protect such resources.
Yes. The proposed grading for the development is
No. 5 I The proposed development will minimize appropriate for the site and the proposed additions stepthe alterations of natural landforms and will not with the site to minimize alterations of site’s naturalresult in undue risks from geological and topography. Drainage recommendations will beerosional forces and/or flood and fire hazards. incorporated into the project, per the preparedhydrology study (attached), that will ensure no undue
risks from geological, erosional, or flood hazards.No. 6 I The proposed development will bevisually compatible with the character of Yes. The accessori dwelling unit will be visuallysurrounding areas, and where feasible, will compatible with the character of the surroundingrestore and enhance visual quality in visually development and will enhance the visual quality of thedegraded areas. property.No. 7 I The proposed development will not have N/A. There are no known archaeological orany adverse impacts on any known paleontological resources within the vicinity or on thearchaeological or paleontological resource. property.No. 8 I The proposed development will be Yes. The accessory dwelling unit will be provided withprovided with adequate utilities, access roads, adequate utilities and access roads as the unit is locateddrainage and other necessary facilities, on a developed lot within an established neighborhood.No. 9 Other public services, including but notlimited to, solid waste and public roadway Yes. The site is considered adequate to provide for solidcapacity have been considered and are adequate waste and the roadways are considered adequate toto serve the proposed development, serve the proposed development.
Pursuant to LBMC Section 25.07.012(0), a coastal development permit application may be approved orconditionally approved only after the Design Review Board has reviewed the development project and madeall the following findings.
(I) The project is in conformity with all the applicable provisions of the general plan, including thecertified local coastal program and any applicable specific plans;
The proposed project is in conformity with the applicable provisions of the General Plan and certifiedLocal Coastal Program as evidenced in Exhibit A. There is no applicable Specific Plan. Additionally,the accessory dwelling unit contributes to the provision of housing opportunities in the City.Therefore, staff believes this finding can be made.
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(2) Any development located between the sea and the first public road paralleling the sea is inconformity with the certified local coastal program and with the public access andpublic recreationpolicies ofChapter 3 ofthe Coastal Act;
The subject property is not located between the sea and the first public road paralleling the sea andis not subject to the public access and public recreation policies of Chapter 3 of the Coastal Act.Therefore, this finding is not applicable.
(3) The proposed development will not have any signfricant adverse impacts on the environment withinthe meaning ofthe California Environmental Quality Act.
The accessory dwelling unit is in compliance with the applicable rules and regulations set forth inthe Municipal Code and will not cause any significant adverse impacts on the environment withinthe meaning of CEQA. Therefore, staff believes this finding can be made.
ADDITIONAL INFORMATION:
Public CorrespondenceStaff has received one letter (attached) from a neighbor expressing comments related to lighting, noise,drainage, landscaping, and construction-related neighborhood impacts.
California Environmental Quality Act (CEQA) DeterminationIn accordance with the California Environmental Quality Act (CEQA) guidelines, the project iscategorically exempt pursuant to Section 15303 - New Construction or Conversion of Small Structures, inthat the project consists of construction and location of limited numbers of new, small structures There isno evidence of any unusual or special conditions that would result in a significant effect on the environment.
Simon-Tenney Family Office+1 (949) 715-0325
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Hello All — I was recently made aware of this project when I saw the “sign board and notice” while travelling downSummit Drive this past week after a meeting. I took the chance to have a look at the site from the roadway and considerwhat Architect Greg Abel has proposed for his client.
I have also reviewed Joe’s, Annette’s, and Hugh’s (“Wire Family”) attached letter and thank them for their thorough andthoughtful comments. I wholly agree with what the Wire Family letter describes as “negative externalities” of long termconcerns or impacts and my wife (Mariella Simon) and I would not be willing to support the project before we have aclear understanding of contingencies that will be considered and implemented to address these potential impacts. Ihave also attached two photographs showing existing views from the property which are discussed below.
My wife and I and our children have quietly enjoyed our home at 630 Agate Street for over twenty-two (22)years. Although we are the “new kids on the block”, like our neighbors, we value the quiet, peacefulness of our Canyonand treasure the vital importance of the Wire Family’s Old Growth Eucalyptus Grove (“Wire Grove”) which is an asset toour neighborhood and a community landmark. It is difficult for me to describe in few words the value of the Wire Groveas it serves a variety of important purposes that go well beyond the “footage price” of the land mass upon which theGrove resides. Clearly Laguna Beach City Staff and Leadership must demand that effective measures be considered tomitigate unintended consequences of this project that might impact neighboring properties, the commons and/orthreaten the health of the Wire Grove which would result in an unfair taking or a usurpation of the Grove’s value.
For clarity, my family believes in private property rights and generally supports each individual’s right to use and quietlyenjoy their property so long as their usage does not-infringe on other’s rights or degrade the value of neighboringproperties, assets or the commons. However the scope and scale of this project I feel presents certain challenges thatshould be addressed through effective contingencies mandated by the City in order to prevent “spill-over” andunintended consequences that would unfairly burden and create negative offsite impacts to adjacent properties
Some specific concerns include:
1. Artificial Lighting - Should not be intensified beyond current baseline conditions and should not cascade off-site and illuminate the Canyon at night. This would usurp the element of darkness valued and much enjoyed byall of the neighborhood. We recommend a qualified lighting consultant/engineer be retained to evaluatebaseline luminosity from the property and help guide final selection of the strength, location, positioning andorientation of the proposed lighting sources to reduce spill-over and preserve the element of darkness in theCanyon that has been in-place for many decades.
2. Noise — At first glance there appears to be a considerable amount of acoustically reflective surfaces beingconsidered in the proposed site design as well as mechanical equipment for the swimming pool and climatecontrol systems that will support the residential complex. We recommend the Project Proponent be required toretain an acoustic engineer to provide direction on appropriate acoustic dampening measures that ensure theproperty complies with Chapter 7.25 (Noise) of the Laguna Beach Municipal Code (“LBMC”)
3. Stormwater Runoff— Proposals to increase hardscape and impervious surfaces on the property createconditions which may, without mitigation, intensify stormwater runoff rates from the site. As it is, the Canyonalready experiences considerable storniflows during wet weather conditions that race through the Canyon’sarroyo and spill out onto Agate and Santa Cruz Streets. These stormflows are already contributing to erosionalissues in the Canyon and on the nearby road surfaces. Increasing runoff rates into the Canyon will furtherexacerbate this matter and any associated mitigation that may be required should not be borne by the public orthe adjacent property owners. We recommend a Hydrologist or Civil Engineer with expertise in drainage issuesbe retained to perform a quantitative evaluation that compares current baseline runoff characteristics to “postdevelopment” (e.g. with project) conditions. We further recommend the City impose restrictions limiting thestormwater runoff rates from the Project to baseline conditions in order to protect downstream properties andthe commons from damaging stormflows.
4. Pool & Spa Drainage — Should be expressly prohibited from being discharged into areas that drain into theCanyon. This is essential to protecting the health of the Old Growth Eucalyptus trees that live in and provideavian habitat within the Wire Grove.
5. Trees & View Scape — Mature trees with crowns extending more than 30’-50’ above the projection of theexisting 741 Summit Drive ridgeline occupy nearly 90-120 degrees of the property’s existing southern andsouthwestern boundaries. The Project Proponent in our opinion, would not enjoy benefits or rights to petitionneighbors or City Officials to force trimming/thinning, crown-cutting or otherwise create clear Pacific Oceanviews where none presently exist. Furthermore, the Project Proponent would not be eligible to avail themselvesof remedies codified in Chapter 12.16 of the LBMC (View Preservation and Restoration) to claim new views byunfairly taking the socio-economic and arboreal value the trees provide to the neighbors and neighborhood.Property owners of 602 Agate St., 605 Agate St., 630 Agate St, 671 Agate St., 1764 Santa Cruz St the Wire Groveopen space, and 717 Summit Drive where vigorous old growth trees are present are indeed responsible tosafely maintain their trees but are not obligated to provide a view-corridor for the Project Proponent. Werecommend that prior to granting entitlement and issuing building permits for this project Officials clarify thisissue by requiring the Project Proponent sign a statement acknowledging their complete and full understandingof the facts of this matter. Wood Cove trees are treasured assets more valuable than Pacific Ocean views. Onemust never be allowed to unfairly take valuable assets without proper recompense.
6. Construction Traffic and Parking — Construction traffic, circulation, and parking will be difficult due to thechallenging project location. Summit Drive has no shoulder, limited parking and difficult ingress/egress to theproject site. It is wholly unacceptable if the burden of construction traffic would spill-over and fall on theneighbors ending up in Woods Cove on Agate Street and Santa Cruz Street in particular. We recommend theCity direct the Project Proponent to develop a Traffic Plan and Circulate it for neighbor comment and feedback.A novel solution needs to be developed to reduce congestion and keep the neighborhood streets clear in theevent of an emergency. We should not be unduly burdened coming in and out of our homes, receiving deliveriesand shipments and providing parking for our guests and visitors.
7. Landscane Design, Plantings and Materials — Ideally should conform with the natural surroundings of theCanyon. We realize planning and materials are subjective and personal preferences but it would be great if thematerial choices and color schemes blend into the surrounding environment. We urge the City to insist thatplant choices do not include any invasive, toxic or fire-unsafe plant species
Finally it is not clear to my why a CEQA review was not required for this project. There are a lot of questions that I don’tclearly understand at this juncture but which may be borne out through the Design Review process. There remain in myview a number of potential environmental issues that may/may-not have been fully fleshed out in the design process orwhich may not have proper contingencies proposed to mitigate potential impacts.
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The good news is the Project Proponent has a fine architect who has a great deal of skin in this community and is a verythoughtful individual with an exceptional track record of delivery in our town.
Sincerely,
Scott Michael TenneySimon-Tenney Family Office+1 (949) 715-0325
Confidentiality DisclaimerThis email is confidential and intended solely for the use of the individual(s) to whom it is addressed. The information contained in this message may beprivileged and confidential and protected from disclosure. If you are not the author’s intended recipient be advised that you have received this email in errorand that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited. If you have received this email in error please delete allcopies, both electronic and printed, and contact the author immediately
Andrew and Gregg,
This letter is to provide our comments, concerns and interests on the two drawings of your ADU andpool project provided to us this week. Enclosed are the views of Annette Williams and Joe Wire, ownersof 671 Agate next door (for Gregg). Neither of us will be able to make your meeting because we areboth on previously scheduled trips out of State. However our father, Hugh, will be at the meeting to seethe presentation.
We appreciate the tours Andrew provided this summer--showing us around the lower yard--during ourdiscussion about the trees Andrew wanted to cut and trim. The ADU and patio retaining wall projectwere mentioned but without the drawings it was hard to really understand the significant height andheft the retaining walls, especially the lower one and the one along our property. The inclusion of apool in the project has not been mentioned to either of us in any of our discussions and doesn’t show upin the renderings we received. We only became aware of that aspect of the project due to the card ourfather received about the meeting next weekend.
Our comments in this letter are based on the two renderings that were later provided to us by Andrew:one a view of the ADU from the back that does not show the retaining wall changes or pool and thesecond a view of the retaining wall changes from our property that does not include the ADU. The tworenderings are insufficient to get a clear view of the project so we will have additional comments oncemore detailed material is provided. It would help our review to have a complete set of plans. Pleaseemail us a detailed set when they are available.
We support the project overall, the ADU and the retaining walls, but have some concerns about theheight of the retaining walls and how the retaining walls and pool may negatively impact our property,as well as potential adverse impacts during project construction.
Long-Term Concerns: Our long-term concerns relate to how to mitigate the negative externalities thatwill come from an additional inhabited dwelling unit, the substantial increase in the height of the landbordering our propriety, and the addition of a significant amount of hardscape and of a pool. Thesenegative externalities relate to noise, light, foot traffic parking (if any), sight lines and runoff.
Noise: This project is being built in a small quiet natural valley with wild growth that all of the propertyowners have previously kept that way. Sound carries extremely well from the property above to ours.Raising the height of the land will increase that sound. Use of the pooi will do the same. We requestthe following concerns be addressed.
--That the height of the patio decks be looked at to see if it can be lowered to keep the walls lower andthe sound more muffled.
--That all mechanical systems of the pool be contained, insulated for sound and be located on mainresidence side of the pool and spa and not on our side or the ocean side.
--That access to/from the ADU be directly up to the driveway to summit via the south side of the mainhouse. The drawings do not show the access path or parking for the ADU in the driveway.
Light: Currently the existing valley is dark at night with minimal light just for safety of people movingaround. Again we request the following be addressed.
--We are pleased to see that the current rendering does not show any lights shining from the mainhouse onto the new patio and pooi. This prevents unnecessary light from shining directly on ourproperty.
--We would like to see the area lights that sit on top of the high stone posts spread around the patiosswapped for low ground lighting that lights up the ground surface, tables and chairs. A larger number oflower powered and lower situated lights tend to throw off less light pollution.
--We would like all lights to use light shields to keep the light on the patio deck and pool and not shiningin the direction of our property.
--It looks from the design that there will be a lot of steps in the project. We request that lights for thosebe at ground to knee level to keep the light from straying.
--We’d like to request that at night all the lights be shut off when the pool area is not in use.
Material and Design Choices: The existing drawing has very high retaining walls that place the patio andthe pool higher than natural grade. The height of the patio/pool complex will increase the noise, lightand sight impacts for our property.
--We would appreciate an examination of lowering the patio decks in the entire complex that wouldmake the patios more a part of the exiting hillside.
--Also to limit the bulk of the design, we request that the corner posts for the patio railings be lowered,thinned and made of similar material to the railing so that they blend into the simple lines of the houseabove and the adjoining properties. It is not clear how the retaining walls will be surfaced. We wouldlike them to have a natural finish and color to fit into the nature on the site.
--The drawing of the patio that we have does not provide information on why the patio south (orbehind) the pool has to be at a higher elevation. The effect creates an even “taller” structure whenviewed from our property. Lowering this patio to the pool height would reduce that effect.
--We would request that the design call for plantings in front of all of the retaining walls to soften theirunnaturally bulky look and to tie them in as much as possible with the hillside and the nature aroundthem. It is not clear how the retaining walls will be surfaced. We would like them to have a naturalfinish and color to fit into the nature on the site.
--It is not clear from the drawings what happens to the trees on the west side of the property thatAndrew proudly showed us in our tours. We request that they remain to break up the view of theretaining walls from below.
--The patio/pool complex introduces a lot of concrete that will create concentrated run off. How willthe runoff be captured and pumped to summit? We do not want runoff from this property formingrivers on our property. We would like the drainage plan to take this into consideration and show howthe runoff will be managed. The plan should provide for a way to drain the pool into the existing sewersystem and not into our property and the Bluebird Canyon drainage. The chlorinated water run-off fromdrainage, splashing or rain collecting on the pool deck could be poisonous for the trees that are belowthe pool causing sickness.
--Although it is not ourfirst choice to introduce a permanent in-ground pool into the current quietnatural space we understand that it is your desire. Please ensure that the design for the patio/poolcomplex and pool cleaning and filtering equipment take into account the natural collection of leavesfrom the existing trees on our property and in the city easement. It is not clear in the drawings howclose the pool is to the property line and the thus the trees. The further from the property line thebetter. If the pool is a necessary element for the project we strongly urge the examination of moving itto the other side of the property where it would get more sun and not be next to the large trees. Thisconcept may impact some of the smallertrees on the property.
Concerns During Construction: The following concerns stem from the extensive amount of digging,moving of soil and concrete work that make up the patio/pool complex.
Noise: Given the close proximity and the higher elevation the noise during construction will be intense.
--We would like construction work limited to between Sam to Spmon weekdays and not on Saturdays,Sundays and Holidays.
Property Damage:
--All access to the site =will not be through our property. We strongly support all personnel, equipmentand material coming from Summit Street. If a need arises for temporary, inconsequential access to ourproperty, approval must be secured from us beforehand. All contractors working on this project mustbe informed to not enter our property without explicit permission..
--All runoff, dirt, material and trash should not be put on our property or allowed to silt up, clog orpollute the natural waterways that flow through our shared valley.
--Given the size, age and close proximity of the trees on the boarder of our property, we are veryconcerned that the roots of those trees not be damaged by the tractor movement or the digging thatlooks to be necessary to complete the existing patio/pool complex as drawn. It would not be good forthe short or long-term health of the trees if their roots are damaged. Designing the constructionoperation to keep all heavy equipment on main house (south) side of the tree side (north) retainingwalls while digging may limit the damage. Moving the pool away from the trees as discussed earlierwould also support that goal.
Thank you for reading through these concerns and requests. Again, we support the project and theCity’s goals for more affordable housing in Laguna Beach, however we have some significant concernsabout the negative externalities of the patio/pool complex. We request that you consider the concernsand work mitigations into the final plans for the project. Sharing a detailed set of plans with us may alsohelp alleviate some concerns.
We are happy to talk to either of you about these concerns or the project.
Thankyou
Annette Williams and Joe Wire
671 Agate.
August 24, 2021
Andrew, Gregg and Warren,
This letter is to follow-up to our first letter to Andrew and Gregg on July 19th 2021 that provided ourcomments, concerns and interests on the two drawings provided of the ADU and pool project. In theintervening month we hope you all have had time to review those concerns and work. We have notreceived a response so have updated the comments in this letter.
As in the first letter, the enclosed are the views of Annette Williams and Joe Wire, owners of 671 Agate.In this letter we have updated our comments based on the receipt of the plans for the patio/poolcomplex and the meeting held with the neighbors last month. Unfortunately, neither of us was able tomake the meeting because we are both on previously scheduled trips out of State. However our father,Hugh Wire, was there and passed on information from the meeting.
We appreciate the tours Andrew provided this summer--showing us around the lower yard--during ourdiscussion about the trees Andrew wanted to cut down and trim. The ADU and patio retaining wallproject were mentioned but not the pool. Also, without the drawings it was hard to understand themassive size of the three patios, the significant height and heft of the retaining walls, especially thelower one and the one along our property, and the how close the project is to the property line. Theinclusion of a pool in the project and the depth and quantity of the dig out required is a surprise and asignificant concern.
Our comments in this letter are based on the two renderings, the plans and the meeting. We haveattached our earlier letter for your reference.
We support the project overall, the ADU and the concept of retaining walls, but have concerns about theheight and heft of the retaining walls, their sharp angles and how close retaining walls are to theproperty line. We would prefer not to have a pool built in the quiet canyon we share. We see that thepool may negatively impact our property and the mature trees between our properties in the near termand over the many years to come. Given the projects size it looks to be an irreversible change to ournatural valley neighborhood that has seen almost no change over the last 40 years. In addition, we areconcerned about the potential adverse impacts during project construction. Although we understandthat at the meeting the neighbors were assured that all construction activity will be from Summit Streetand all runoff and debris will be captured on the property. We have not seen a plan for this so if it is notthe case, please inform us.
What follows is a list of our concerns, first long-term concerns the project brings to the neighborhoodand the short-term or temporary concerns brought up by the construction of the project.
Long-Term Concerns: Our long-term concerns relate to how to mitigate the negative externalities thatwill come from the substantial increase in the height of the land bordering our propriety, the closenessand unnatural shape of the retaining walls, the addition of a significant amount of hardscape, a pool andan additional inhabited dwelling unit. These negative externalities relate to noise, light, foot trafficparking (if any), sight lines and runoff.
This project is being built in a small quiet, natural valley with wild growth that all of the property ownershave previously kept that way. This is a type of land that has become increasing rare in Laguna.
Noise: Sound carries extremely well from the property above to ours. Raising the height of the land willincrease that sound. Use of the pool will do the same. We request the following concerns beaddressed.
--That the height of the patio decks especially the pool deck be looked at to see if it can be lowered tokeep the retaining walls lower and the sound more muffled.
--That all mechanical systems of the pool be contained, insulated for sound and be located on mainresidence side of the pool and spa and not on our side or the ocean side (as labeled in plans received).
--That access to/from the ADU be directly up to the driveway to summit via the south side of the mainhouse. The drawings do not show the access path or parking for the ADU in the driveway.
Light: Currently the existing valley is dark at night with no or minimal light that is there just to be usedfor safety of people moving around. Again we request the following be addressed.
--We are pleased to see that the current rendering does not show any lights shining from the mainhouse onto the new patio and pool. This prevents unnecessary light from shining directly on ourproperty.
--We would like to see the area lights that sit on top of the high stone posts spread around the patiosswapped for low ground lighting that lights up the ground surface, tables and chairs. A number of lowerpowered and lowersituated lights tend to throw off less light pollution.
--We would like all lights to use light shields to keep the light on the patio deck and pool and not shiningup or in the direction of our property.
--It looks from the design that there will be a lot of steps in the project. We request that lights for thosebe at ground to knee level to keep the light from straying.
--We’d like to request that at night all the lights be shut off when the pool area is not in use.
Material and Design Choices: The existing drawing has very high retaining walls that place the patio andthe pool higher than natural grade. The height of the patio/pool complex will increase the noise, lightand sight impacts for our property. We would appreciate an examination of lowering the patio decks inthe complex.
--The design of the larger retaining walls at the lower end of the property are a complete departurefrom the design of the rest of the patio/pool complex. All of the other walls in the project are contouredinto the downward sloping land. We understand that this makes the patio spaces more appealing to theusers. We request that same approach be taken to the two lower walls on the west and south side ofthe project. Since those are the walls that we and the other neighbors will be looking at it would bemake project equally appealing to the rest of the project if they match the projects overall design andtake on a contoured shape.
--We would prefer if the project did not introduce a permanent in-ground pool into the current quietnatural space but we understand that it is the desire. To accommodate the request of contoured andlower west and south retaining walls, we request that the project slide the pool to the east where itcould betterfit with contoured retaining walls. In addition this would move the pool from the property
line and the existing large trees and reduce the concern that the dig-out, for the deep pool and theretaining walls, will cause damage to the root structure and thus health of the existing mature trees.
--Please ensure that the design for the patio/pool complex and pool cleaning and filtering equipmenttake into account the natural collection of leaves from the existing trees on our property and those inthe city easement between our properties.
--Also to limit the bulk of the design, we request that the stone covered corner and mid-posts for thepatio railings be lowered, thinned and made of similar material to the railing so that they blend into thesimple lines of the house above and the adjoining properties and are more in keeping with the naturalaesthetic of the area.
--We would request that the design call for plantings in front of all of the retaining walls to soften theirbulky look and to tie them in as much as possible with the hillside and the nature around them. It is notclear how the retaining walls will be surfaced. We would like them to have a natural finish and color tofit into the nature on the site.
--The patio/pool complex size and height introduces a lot of concrete that will create significantconcentrated runoff. How will the runoff be captured and pumped to summit? We do not want runofffrom this new structure forming concentrated rivers of water on our property. We would like thedrainage plan to take this into consideration and show how the runoff will be managed.
--The plan should provide for a way to drain the pool into the existing sewer system and not into ourproperty and the Bluebird Canyon drainage. The chlorinated water run-off from drainage, splashing orrain collecting on the pool deck could be poisonous for the trees that are below the pool causingsickness for them.
Concerns During Construction: The following concerns stem from the extensive amount of digging,moving of soil and concrete work that will be required to build the patio/pool complex.
Noise: Given the close proximity and the higher elevation the noise during construction will be intense.
--We would like construction work limited to between 8am to 5pm on weekdays and not on Saturdays,Sundays and Holidays.
Property Domage:
--As mentioned we understand that all access to the construction site will be from Summit Street andwill not be through our property. If a need arises for temporary, inconsequential access to our property,approval must be secured from us beforehand. All contractors working on this project must beinformed to not enter our property without explicit permission before they begin work so we don’t haveany confusion.
--All runoff, dirt, material and trash should not be put on our property or allowed to silt up, clog orpollute the natural waterways that flow through our shared valley.
--Given the size, age and close proximity of the trees on the boarder of our property, we are veryconcerned that the roots of those trees not be damaged by the tractor movement or the digging that
looks to be necessary to complete the existing patio/pool complex as drawn. It would not be good forthe short or long-term health of the trees if their roots are damaged. Designing the constructionoperation to keep all heavy equipment on main house side of the retaining walls while digging may limitthe damage. As mentioned contouring the retaining walls will also move the need to the east.
Thank you for reading through these concerns and requests. Again, we support the project and theCity’s goal for more affordable housing in Laguna Beach, however we have some significant concernsabout the negative externalities of the patio/pool complex. We request that you consider the concernsand work mitigations into the final plans for the project.
As requested by the City we will share these letters with them and invite them to view the project fromour property.
We are happy to talk to either of you about these concerns or the project.
/ q4-~2 ~2 r CRMS GroupP0 Box 70June Lake, CA 93529
Attention: Bob Strong
Subject: Peer Review for 741 Summit Drive, Laguna Beach, CA
A second Peer Review has been conducted for the Subject Project. The review has beenbased on the following document:
• Revised Preliminary Hydrology Study Dated February 1,2021, IncludingAnderson/Geology Preliminary Exploration for Design and Construction
The revised Study is hereby approved.
Please submit one revised report directly to me, at the address shown below, for myrecords. I will provide the City with the revised report I now have which is wet signedand sealed.
Appendix 3 Setback Review of Existing Water Course
Appendix 4 Off Site Upstream Hydrology and Analysis of Existing On Site Channel
Appendix 5 Existing Condition Hydrology Map
Appendix 6 Proposed Condition Hydrology Mop
Hydrology and Hydraulic Report February 2021
1.0 INTRODUCTION
1.1 GEOGRAPHIC SETTING
The project and surroundng area consists of 20,473 sf± and is located in the City of LagunaBeach. The area is bounded by Summit Drive on the north and single family homes on the south,west and east. A natural drainage course runs northwesterly through the southwest corner of theproject site.
1 .2 PURPOSE OF THIS REPORT
The purpose of this report is to accomplish the following objectives:
To determine the storm water discharges generated within the site for the pre and postdevelopment conditions and determine if the storm water discharge for the proposed condition islimited to no more than the discharge for the existing condition.
To demonstrate that the storm water and flood protection goals as outlined in the Orange CountyDesign Manual have been met
1.3 REFERENCES
• Orange County Hydrology Manual
• Orange County Local Drainage Manual
• AES Hydrology Software
• HEC RAS Software
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HydroIo~y and Hydrauttc Report February 2021
2.0 EXISTING TOPOGRAPHIC &HYDROLOGIC CONDITIONS
2.1 EXISTING TOPOGRAPHY
The project site fronts on Summit Drive. The property slopes down from the street at an elevationof 217 to 164.
2.2 EXISTING DRAINAGE PATTERN
The site flows westerly from Summit Drive and northwesterly within a natural drainage coursethrough the project site. The condition of this drainage course was reviewed by AndersonGeology. See Appendix 3
2.3 EXISTING STORM DRAIN FACILITIES
A small drainage line exists on the southerly side of the property. This line picks up the dischargefrom the driveway area and conveys it westerly to the existing drainage course on the property.An 1S~ public storm drain line outlets onto the property near the north east corner of the site.This line picks up approximately 4.6 acres upstream of the project site.
3.0 PROPOSED FACILITIES
3.1 PROJECT DESCRIPTION
An addition to the existing home and a pool side patio will be constructed within the property.The proposed development will not alter the existing drainage pattern and no area diversions areproposed.
3.2 PROPOSED STORM DRAIN SYSTEM
A new local residential storm drain system will be installed adjacent to the proposed home andwithin the proposed patios of the home on the northerly side of the property. This system willdischarge to the existing drainage course running through the westerly portion of the property.
Hydrology and Hydraulic Report February 2021
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tO HYDROLOGY4.1 STORM FREQUENCY
This study is intended to determine discharges for use in the design of storm drains and inletswithin the proposed home site. Because numerous small sumps are located throughout theproject and to ensure that the County of Orange Flood Protection Goals are met, a 100-yearfrequency was chosen as the minimum design criteria.
4.2 METHODOLOGY
This study was prepared in conformance with the Orange County Hydrology Manual. A.E.S.Computer Software was utilized to compile the hydrologic data and to determine the peakdischarges for the pre and post development conditions. The following table summarizes thepervious and impervious areas for each sub area in the pre and post condition. This informationwas used to determine landuse designations in the AES software.
Existing Sub Areas
Sub Area Impervious Area Total Area % Impervious
Al 0.05 AC 0.05 AC 100%
A-2 0.06 AC 0.24 AC 25%
B-l 0.04 AC 0.14 AC 29%
8-2 0.00 AC 0.01 AC 0%
C 0.00 AC 0.03 AC 0%
Proposed Sub Areas
Sub Area Impervious Area Total Area % Impervious
Al 0.05 AC 0.05 AC 100%
42 0.06 AC 0.24 AC 25%
B-l 0.02 AC 0.06 AC 0.33%
B-2 0.00 AC 0.01 AC 0%
C 0..02 AC 0.04 AC 50%
D 0.00 AC 0.02 AC 0%
E 0.05 AC 0.05 AC 100%
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Hydrology and Hydraulic Report February 2021
5.0 HYDRAULICS
5.1 METHODOLOGY
Pipe sizes will be determined during final design of the site work using maximum capacity withinvarious size pipe. The existing drainage channel on the property which conveys storm water fromthe 1W outlet draining the area upstream of the site was analyzed using HEC RAS software. SeeAppendix 4
6.0 DESIGN CRITERIAThe proposed storm drain systems will be designed to be consistent with the following goals andguidelines:
All buildings shall be protected from flooding during a 100-year frequency storm.
Velocity should not exceed 20 FPS in a standard wall R.C.P.
Where velocity exceeds 20 FPS, a special wall R.C.P. with a minimum of 1½-inch steel clearance onthe inside surface shall be used.
Maximum velocity in special cover R.C.P. shall be 45 FPS.
On local streets one lane shall be free of storm water in a 25-year storm event.
Maximum W.S. in CB’s for design conditions shall be 0.5’ below inlet (FL) elevation.
Once water is picked up in a storm drain, it should remain in the system.
Pipe size may not be decreased downstream without agency approval.
7.0 RESULTS AND CONCLUSIONSAs a result of site development it is our opinion that the proposed local residential storm drainsystem, designed to a Storm Frequency, will not have an adverse effect on any of the existingor proposed improvements within the project or adjacent area. In addition, all design criteriaoutlined above have been met including protection of buildings during the 100 year event. Noponding of storm water occurs within 1’ of building finish floor.
As a result of the home improvements the post development discharge from the site is less thanthe existing pre development discharge for the 100 year event.
The pre-development 100 year event discharge is 2.50 cfs and the post development 100 yearevent discharge is 2.46 cfs. No detention of storm water is needed to limit post developmentdischarge.
Hydrology and Hydraulic Report February 2021
APPENDIX 1
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
************************** DESCRIPTION OF STUDY~* EXIST CONDITION *
* 100 YEAR EVENT *
* *
**
FILE NAME: SUEX100.DATTIME/DATE OF STUDY: 01:08 02/01/2021
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
....*TIMEOFCONCENTRATION MODEL*__
USER SPECIFIED STORM EVENT(YEAR) = 100.00SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95*DATA BANK RAINFALL USED**ANTECEDENT MOISTURE CONDITION (AMC) III ASSUMED FOR RATIONAL METHOD*
*USERDEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*HALF- CROWN TO STREET—CROSSFALL: CURB GUTTER-GEOMETRIES: MANNINGWIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:1. Relative Flow—Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) — (Top—of-Curb)2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THANOR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER_5PECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED
FLOW PROCESS FROM NODE 10.00 TO NODE 11.00 IS CODE = 21. >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<<
Tc = K*[(LENGTH** 3.00)!(ELEVATION CHANGE)]**O.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187
SUBAREA Tc AND LOSS RATE DATA(N1C III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CN (MIN.)COMMERCIAL D 0.05 0.20 0.100 91 5.00SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100SUBAREA RUNOFF(CFS) = 0.28TOTAL AREA(ACRES) = 0.05 PEAK FLOW RATE(CFS) 0.28
FLOW PROCESS FROM NODE 11.00 TO NODE 12.00 IS CODE = 31
>>>>>COMPUTE PIPE—FLOW TRAVEL TIME THRU SUBAREA<<<<<>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON—PRESSURE FLOWK<<<<
ELEVATION DATA: tJPSTREAN(FEET) 208.04 DOWNSTREAN(FEET) 167.50FLOW LENGTH(FEET) = 134.00 MANNING’S N 0.013ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 4.000DEPTH OF FLOW IN 4.0 INCH PIPE IS 1.4 INCHESPIPE—FLOW VELOCITY(FEET!SEC.) = 10.05ESTIMATED PIPE DIANETER(INCH) = 4.00 NUMBER OF PIPES = 1PIPE—FLOW(CFS) = 0.28PIPE TRAVEL TIME(MIN.) = 0.22 Tc(MIN.) = 5.22LONGEST FLOWPATH FROM NODE 10.00 TO NODE 12.00 = 222.00 FEET.
FLOW PROCESS FROM NODE 12.00 TO NODE 12.00 IS CODE 81
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
MAINLINE Tc(MIN.) = 5.22* 100 YEAR RAINFALL INTENSITY(INCH!HR) = 6.035
SUBAREA LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CNRESIDENTIAL“2 DWELLINGS!ACRE” D 0.24 0.20 0.700 91SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) =. 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.700SUBAREA AREA(ACRES) = 0.24 SUBAREA RUNOFF(CFS) = 1.27EFFECTIVE AREA(ACRES) = 0.29 AREA-AVERAGED Fsn(INCH/HR) 0.12AREA-AVERAGED Fp(INCJ-1!HR) = 0.20 AREA-AVERAGED Ap = 0.60TOTAL AREA(ACRES) = 0.3 PEAK FLOW RATE(CFS) = 1.54
Tc = K*[(LENGTH** 3.0O)/(ELEVATION CHANGE)J**O.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.214* 100 YEAR RAINFALL INTENSITY(INCH!HR) 6.040
SUBAREA Tc AND LOSS RATE DATA(N4C III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CN (MIN.)NATURAL GOOD COVER“OPEN BRUSH” D 0.01 0.20 1.000 95 5.21SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 1.000SUBAREA RUNOFF(CFS) = 0.05TOTAL AREA(ACRES) = 0.01 PEAK FLOW RATE(CFS) = 0.05
FLOW PROCESS FROM NODE 22.00 TO NODE 23.00 IS CODE = 21
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<<
Tc = K*[(LENGTH** 3.OOy/(ELEVATION CHANGE)]**O.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000* 100 YEAR RAINFALL INTENSITY(INCH!HR) — 6.187
SUBAREA Tc AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CN (MIN.)RESIDENTIAL“2 DWELLINGS!ACRE” D 0.14 0.20 0.700 91 5.00SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) — 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.700SUBAREA RUNOFF(CFS) = 0.76TOTAL AREA(ACRES) = 0.14 PEAK FLOW RATE(CFS) 0.76
Tc = K*((LENGTH** 3.00)./(ELEVATION CHANGE)]**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.875* 100 YEAR RAINFALL INTENSITY(INCH!HR) = 5.641
SUBAREA Tc AND LOSS RATE DATA(AMC III):
DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc. LAND USE GROUP (ACRES) (INCH/BR) (DECIMAL) CM (MIN.)NATURAL GOOD COVER“OPEN BRUSH” D 0.03 0.20 1.000 95 5.87SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap 1.000SUBAREA RUNOFF(CFS) = 0.15TOTAL AREA(ACRES) = 0.03 PEAK FLOW RATE(CFS) 0.15
END OF STUDY SUMMARY:TOTAL AREA(ACRES) = 0.0 TC(MIN.) = 5.87EFFECTIVE AREA(ACRES) = 0.03 AREA-AVERAGED Fm(INCH/HR)= 0.20AREA—AVERAGED Fp(INCH!HR) = 0.20 AREA-AVERAGED Ap = 1.000PEAK FLOW RATE(CFS) 0.15
END OF RATIONAL METHOD ANALYSIS
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Hydrology and Hydraulic Report February 202?
APPENDIX 2
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
************************** DESCRIPTION OF STUDY ~~~~““““
* PROPOSED CONDITION* 100 YEAR EVENT*
FILE NAME: SUPR100.DATTIME/DATE OF STUDY: 01:59 02/01/2021
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
....*TIME...OF..CONCENTRATION MODEL*__
USER SPECIFIED STORM EVENT(YEAR) = 100.00SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95*DATA BANK RAINFALL USED**ANTECEDENT MOISTURE CONDITION (At4C) III ASSUMED FOR RATIONAL METHOD*
*USER...DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNINGWIDTH CROSSFALL IN- / OUT-/RAnK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
Tc = K*[(LENGTH** 3.0O)/(ELEVATION CHANGE)}**O.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) 5.000* 100 YEAR RAINFALL INTENSITY(INCH/HR) 6.187
SUBAREA Tc AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)COMMERCIAL D 0.05 0.20 0.100 91 5.00SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100SUBAREA RUNOFF(CFS) = 0.28TOTAL AREA(ACRES) = 0.05 PEAK FLOW RATE(CFS) = 0.28
FLOW PROCESS FROM NODE 11.00 TO NODE 12.00 IS CODE 31
>>>>>COMPUTE PIPE—FLOW TRAVEL TIME THRU SUBAREA<<<<<>>>>>USING COMPUTER—ESTIMATED PIPESIZE (NON—PRESSURE FLOW)<<<<<
ELEVATION DATA: UPSTREAM(FEET) = 208.04 DOWNSTREAM(FEET) = 167.50FLOW LENGTH(FEET) = 134.00 MANNING’S N = 0.013ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 4.000DEPTH OF FLOW IN 4.0 INCH PIPE IS 1.4 INCHESPIPE—FLOW VELOCITY(FEET!SEC.) = 10.05ESTIMATED PIPE DIANETER(INCH) 4.00 NUMBER OF PIPES = 1PIPE—FLOW(CFS) 0.28PIPE TRAVEL TIME(MIN.) 0.22 Tc(MIN.) = 5.22LONGEST FLOWPATH FROM NODE 10.00 TO NODE 12.00 = 222.00 FEET.
FLOW PROCESS FROM NODE 12.00 TO NODE 12.00 IS CODE = 81
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
MAINLINE Tc(MIN.) = 5.22* 100 YEAR RAINFALL INTENSITY(INCH!HR) = 6.035
SUBAREA LOSS RATE DATA (P.NC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CNRESIDENTIAL“2 DWELLINGS/ACRE” D 0.24 0.20 0.700 91SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.700SUBAREA AREA(ACRES) = 0.24 SUBAREA RUNOFF(CFS) = 1.27EFFECTIVE AREA(ACRES) = 0.29 AREA-AVERAGED Fin(INCH/HR) = 0.12AREA—AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.60TOTAL AREA(ACRES) = 0.3 PEAK FLOW RATE(CFS) = 1.54
Tc = K*[(LENGTH** 3.OO)/(ELEVATION CHANGE)]**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.214* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.040
SUBAREA Tc AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp
LAND USE GROUP (ACRES) (INCH!HR)NATURAL GOOD COVER“OPEN BRUSH” DSUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 1.000SUBAREA RUNOFF(CFS) = 0.05TOTAL AREA(ACRES) = 0.01 PEAK FLOW RATE(CFS) =
Tc = K*[(LENGTH** 3.00),’ (ELEVATION CHANGE)]**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000* 100 YEAR RAINFALL INTENSITY(INCH!HR) = 6.187
SUBAREA Tc AND LOSS RATE DATA(AM4C III)DEVELOPMENT TYPE! SCS SOIL AREA
LAND USE GROUP (ACRES)CONDOMINIUMS D 0.06SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.350SUBAREA RUNOFF(CFS) = 0.33TOTAL AREA(ACRES) = 0.06 PEAK FLOW RATE(CFS) =
Tc = K*[(LENGTH** 3.O0)/(ELEVATION CHANGE)J**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000* 100 YEAR RAINFALL INTENSITY(INCH!HR) = 6.187
SUBAREA Tc AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/FIR) (DECIMAL) CM (MIN.)RESIDENTIAL“5—7 DWELLINGS/ACRE” D 0.04 0.20 0.500 91 5.00SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.500SUBAREA RUNOFF(CFS) = 0.22TOTAL AREA(ACRES) = 0.04 PEAK FLOW RATE(CFS) = 0.22
FLOW PROCESS FROM NODE 31.00 TO NODE 32.00 IS CODE = 31
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<>>>>>USING COMPUTER—ESTIMATED PIPESIZE (NON—PRESSURE FLOW)<<’X<
ELEVATION DATA: FjPSTREAM(FEET) = 183.00 DOWNSTREAN(FEET) = 180.00FLOW LENGTH(FEET) = 34.00 MANNING’S N = 0.013ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 4.000DEPTH OF FLOW IN 4.0 INCH PIPE IS 1.8 INCHESPIPE—FLOW VELOCITY(FEET,/SEC.) = 5.92ESTIMATED PIPE DIANETER(INCH) = 4.00 NUMBER OF PIPES = 1PIPE—FLOW(CFS) = 0.22PIPE TRAVEL TIME(MIN.) = 0.10 Tc(MIN.) = 5.10LONGEST FLOWPATH FROM NODE 30.00 TO NODE 32.00 = 102.00 FEET.
FLOW PROCESS FROM NODE 32.00 TO NODE 32.00 IS CODE = 81
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<((<
MAINLINE Tc(MIN.) = 5.10* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.120
SUBAREA LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CNCOMMERCIAL D 0.05 0.20 0.100 91SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100SUBAREA AREA(ACRES) = 0.05 SUBAREA RUNOFF(CFS) = 0.27
Tc = K*[(LENGTH** 3.O0)/(ELEVATION CI~IANGE)J**0.2OSUBAREA ANALYSIS USED MINIMUM TC(MIN.) = 5.875* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.641
SUBAREA Tc AND LOSS RATE DATA(ANC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CM (MIN.)NATURAL GOOD COVER“OPEN BRUSHT’ D 0.02 0.20 1.000 95 5.87SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap 1.000SUBAREA RUNOFF(CFS) 0.10TOTAL AREA(ACRES) = 0.02 PEAK FLOW RATE(CFS) = 0.10
END OF STUDY SUMMARY:TOTAL AREA(ACRES) 0.0 TC(MIN.) = 5.87EFFECTIVE AREA(ACRES) = 0.02 AREA-AVERAGED Fm(INCH/HR)= 0.20AREA—AVERAGED Fp(INCH!HR) = 0.20 AREA-AVERAGED Ap = 1.000PEAK FLOW RATE(CFS) = 0~10
END OF RATIONAL METHOD ANALYSIS
Hydrology and Hydraulic Report February 2021
.APPENDIX 3
Anderson~eo1ogy
October 2, 2020
Project No. 20050-01
To: Mr. Andrew Nocella741 Summit DriveLaguna Beach, California, 92651
Attention: Gregg Abel Design & Construction Inc.
Subject: Development Setbacks for Existing Blucline Stream Along South Project Boundary741 Summit Drive, City of Laguna Beach, California
References: Preliminary Geotechnical Exploration for Design and Construction of ProposedAccessory Dwelling Unit (ADU) & Hardscape Improvements, 741 Summit Drive, Cityof Laguna Beach, California (Anderson Geology, Sept. 152020)
At your request, Peter Anderson of ANDERSON GEOLOGY CONSULTING, LLC. (AG) has performeda limited site reconnaissance of the subject property in order to review the existing blueline drainagealong the south property boundary for the purpose of determining development setbacks in conformancewith the requirements of the city of Laguna Beach. The subject drainage extends from Summit Drive, tothe northeast of the subject site, and extends offsite to the west, bisecting the southern portion of theproperty. The drainage has been partially channelized with a 4-foot concrete block wall along west bank,extending offsite to the northwest. The drainage appears to be ephemeral in nature and was dry at thetime of our onsite investigation. Flow within the drainage is anticipated to be primarily associated withperiodic surface runoff during seasonal precipitation. No evidence of significant scour or erosion wasnoted.
A review of the existing drainage was performed utilizing the site topographic profile and proposed sitelayout included on the Site Plan (Sheet A-I), prepared by Gregg Abel Design & Construction Inc. Basedon the findings of our site investigation, the existing drainage was found to have a minimum horizontalsetback of 25-feet from foundation elements for the proposed improvements to the existing residentialstructure. In addition, the observed flow line of the adjacent drainage (el l65’-170’) is greater than 10-feet lower in elevation than the proposed improvements at foundation grades (el I 80’+). Furthermore, theadjacent properties to south and southwest of the subject site are significantly lower in elevation and willbe subject to inundation in the event of flood event that overflows the existing channel.
In conclusion, the proposed improvements to the subject site maintain a minimum 25-foot horizontalsetback from the existing drainage along the south property boundary. Based on anticipated foundationembedment’s into competent bedrock material, elevation differences between the proposed improvementsand flow line of the adjacent drainage, and anticipated structural setbacks provided, the adjacent bluelinedrainage is not anticipated to be a significant construction constraint and no special recommendationsbeyond those provided in the referenced geotechnical design report are warranted at this time.
, Our review and analysis has been performed using the degree of care and skill ordinarily exercised undersimilar circumstances by reputable geotechnical consultants practicing in this or similar localities. Nowarranty, expressed or implied, is made as to the conclusions and professional advice included in thisletter.
The opportunity to be of service is appreciated. Please contact us if you have any questions, comments orrequire any additional information.
Respectfully submitted,
ANDERSON GEOLOGY CONSULTING, LLC.
Peter Anderson CEG 2596
741 SummILDr
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Hydrology and Hydraulic Report February 2021
APPENDIX 4
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
FILE NAME: SUOF100.DATTIME/DATE OF STUDY: 10:48 01/31/2021
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
__*TIME_OF_CONCENTRATION MODEL*__
USER SPECIFIED STORM EVENT(YEAR) = 100.00SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00SPECIFIED PERCENT OF GRADIENTS (DECIMAL) TO USE FOR FRICTION SLOPE = 0.95*DATA BANK RAINFALL USED**ANTECEDENT MOISTURE CONDITION (AMC) III ASSUMED FOR RATIONAL METHOD*
*USER_DEFINED STREET—SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*HALF— CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNINGWIDTH CROS5FALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
Ta = K*[(LENGTH** 3.0O)/(ELEVATION CHANGE)J**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.163* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.074
SUBAREA Ta AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Ta
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CM (MIN.)RESIDENTIAL“3—4 DWELLINGS/ACRE” D 1.15 0.20 0.600 91 5.16SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.600SUBAREA RUNOFF(CFS) = 6.16TOTAL AREA(ACRES) = 1.15 PEAK FLOW RATE(CFS) = 6.16
FLOW PROCESS FROM NODE 20.00 TO NODE 70.00 IS CODE 41
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<>>>>>USING USER—SPECIFIED PIPESIZE (EXISTING ELEMENTK<<<<
ELEVATION DATA: UPSTREAN(FEET) = 262.00 DOWNSTREAN(FEET) = 200.00FLOW LENGTH(FEET) 210.00 MANNING’S N = 0.013DEPTH OF FLOW IN 12.0 INCH PIPE IS 4.7 INCHESPIPE—FLOW VELOCITY(FEET/SEC.) 21.49GIVEN PIPE DIANETER(INCH) = 12.00 NUMBER OF PIPES 1PIPE—FLOW(CFS) = 6.16PIPE TRAVEL TIME(MIN.) = 0.16 Tc(MIN.) = 5.33LONGEST FLOWPATH FROM NODE 10.00 TO NODE 70.00 = 490.00 FEET.
FLOW PROCESS FROM NODE 70.00 TO NODE 70.00 IS CODE 10
>>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK 4 1 <<<<<
Ta = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20SUBAREA ANALYSIS USED MINIMUM Ta(MIN.) = 7.057* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.079
SUBAREA Ta AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Ta
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)RESIDENTIAL“3—4 DWELLINGS/ACRE” D 1.15 0.20 0.600 91 7.06SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.600SUBAREA RUNOFF(CFS) = 5.13
TOTAL AREA(ACRES) 1.15 PEAK FLOW RATE(CFS) = 5.13.FLOW PROCESS FROM NODE 40.00 TO NODE 40.00 IS CODE =
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
TOTAL NUMBER OF STREAMS = 2CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:TIME OF CONCENTRATION(MIN.) = 7.06RAINFALL INTENSITY(INCH!HR) = 5.08AREA-AVERAGED Fm(INCH/HR) = 0.12AREA-AVERAGED Fp(INCI-1/HR) = 0.20AREA—AVERAGED Ap = 0.60EFFECTIVE STREAM AREA(ACRES) = 1.15TOTAL STREAM AREA(ACRES) 1.15PEAK FLOW RATE(CFS) AT CONFLUENCE 5.13
FLOW PROCESS FROM NODE 50.00 TO NODE 40.00 IS CODE = 21
>>>>>RATIONAL METHOD INITIAL SUBAREA A±4ALYSIS<<<<<>>USE TIME-OF—CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<<
Tc = K*[(LENGTH** 3.OO)!(ELEVATION CHANGEfl**0.20SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.414* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.365
SUBAREA TC AND LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH!HR) (DECIMAL) CN (MIN.)RESIDENTIAL“3—4 DWELLINGS!ACRE” D 1.38 0.20 0.600 91 6.41SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH!HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap 0.600SUBAREA RUNOFF(CFS) = 6.51TOTAL AREA(ACRES) = 1.38 PEAK FLOW RATE(CFS) = 6.51
FLOW PROCESS FROM NODE 40.00 TO NODE 40.00 IS CODE =
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
TOTAL NUMBER OF STREAMS = 2CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:TIME OF CONCENTRATION(MIN.) = 6.41RAINFALL INTENSITY(INCH/’HR) = 5.36AREA—AVERAGED Fm(INCH/’HR) = 0.12AREA—AVERAGED Fp(INCH!HR) = 0.20AREA—AVERAGED Ap = 0.60EFFECTIVE STREAM AREA(ACRES) = 1.38TOTAL STREAM AREA(ACRES) = 1.38
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 10.00INSIDE STREET CROSSFALL(DECIMAL) = 0.018OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF 1STREET PARKWAY CROSSFALL(DECIMAL) 0.020Manning’s FRICTION FACTOR for Streetfiow Section(curb—to—curb) = 0.0150Manning’s FRICTION FACTOR for Back—of—Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 13.48STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:STREET FLOW DEPTH(FEET) = 0.28HALFSTREET FLOOD WIDTH(FEET) 19.09AVERAGE FLOW VELOCITY(FEET/SEC.) = 7.13PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 2.02
STREET FLOW TRAVEL TIME(MIN.) = 0.65 Tc(MIN.) 7.07* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.074
SUBAREA LOSS RATE DATA(AMC III):DEVELOPMENT TYPE! SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/BR) (DECIMAL) CNRESIDENTIAL
“3—4 DWELLINGS/ACRE” 0 0.91 0.20 0.600 91SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.600SUBAREA AREA(ACRES) = 0.91 SUBAREA RUNOFF(CFS) = 4.06EFFECTIVE AREA(ACRES) = 3.34 AREA-AVERAGED Fm(INCH/HR) = 0.12AREA—AVERAGED Fp(INCH/HR) = 0.20 AREA—AVERAGED Ap = 0.60TOTAL AREA(ACRES) = 3.4 PEAK FLOW RATE(CFS) = 14.87
END OF SUBAREA STREET FLOW HYDRAULICS:DEPTH(FEET) = 0.29 HALFSTREET FLOOD WIDTH(FEET) = 19.98FLOW VELOCITY(FEET/SEC.) = 7.24 DEPTH*VELOCITY(FT*FT/SEC.) = 2.11LONGEST FLOWPATH FROM NODE 30.00 TO NODE 60.00 = 760.00 FEET.
FLOW PROCESS FROM NODE 60.00 TO NODE 60.00 IS CODE 7
>>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE< GRATE INLET CAPACITY
USER-SPECIFIED VALUES ARE AS FOLLOWS:TC(MIN.) = 7.07 RAINFALL INTENSITY(INCH/HR) 5.07EFFECTIVE AREACACRES) = 3.34TOTAL AREA(ACRES) = 3.40 PEAK FLOW RATE(CFS) = 10.30AREA—AVERAGED Fm(INCH/HR) 0.12 AREA—AVERAGED Fp(INCH/HR) = 0.20AREA-AVERAGED Ap = 0.60NOTE: EFFECTIVE AREA IS USED AS THE TOTAL CONTRIBUTING AREA FOR ALL
A RESOLUTION OF THE OF THE DESIGN REVIEW BOA1Th OFTHE CITY OF LAGUNA BEACH APPROVING DESIGN REVIEW21-9501, COASTAL DEVELOPMENT PERMIT 21-9500, ANDVARIANCE 21-9502 FOR MODIFICATIONS TO A PRIORAPPROVAL AND NEW ACCESSORY DWELLING UNIT, ANDAPPROVING A CATEGORICAL EXEMPTION PURSUANT TOTHE CALIFORNIA ENVIRONMENTAL QUALITY ACT.
741 Summit Drive [ APN: 644-252-02
WFIEREAS, on August 17, 2021, a notice was mailed to all property owners within a 300radius and tenants within a 100? radius announcing the September 9, 2021 public hearing of theDesign Review Board for the proposed project; and
WHEREAS, on September 9, 2021, the Design Review Board carefhlly considered the oraland documentary evidence and arguments presented at the duly noticed hearing.
NOW, THEREFORE, THE DESIGN REVIEW BOARD OF THE CITY OF LAGUNABEACH DOES HEREBY FIND, DETERMINE AND RESOLVE AS FOLLOWS:
Section 1: Design Review 21-9501, Coastal Development Permit 21-9500, andVariance 21-9502 for modifications to a prior approval and new accessory dwelling unit at anexisting single-family residence (“Proposed Project”) are approved. The Proposed Project isexempt from the provisions of the California Environmental Quality Act in accordance with StateCEQA Guidelines Section 15303 - New Construction or Conversion of Small Structures, in thatthe project consists of construction and location of limited numbers of new, small structures; and
Section 2: The Proposed Project is consistent with the applicable Title 25 developmentstandards and guidelines for the reasons and factual basis set forth on page 3 of the Staff Report.
Section 3: The proposed project is consistent with the Design Review criteria relatedto access, design articulation, design integrity, environmental context, general plan compliance,landscaping, lighting, neighborhood compatibility, privacy, sustainability, and view equity for thereasons and factual basis set forth on pages 3-5 of the Staff Report.
Section 4: The Variance findings can be made for the Proposed Project for the reasonsand factual basis set forth on pages 5-7 of the Staff Report.
Section 5: The Coastal Development Permit criteria can be made for the ProposedProject for the reasons and factual basis set forth on pages 7-8 of the Staff Report.
Section 6: The Coastal Development Permit findings can be made for the ProposedProject for the reasons and factual basis set forth on pages 8-9 of the Staff Report.
Page 1 of 3
Section 7: Expiration. The proposed project will expire if development has notcommenced within two years from the final action of the approval authority on the application.Development, once commenced, shall be pursued in a diligent manner and completed in areasonable period of time. An application for extension of the permit must be made prior to theexpiration date.
Section 8: Terms and Conditions Run with the Land. These terms and conditions shallbe perpetual, and it is the intention of the approval authority and the permittee to bind all futureowners and possessors of the subject property to the terms and conditions.
Section 9: Plan Reliance and Modification Restriction. In the absence of specificprovisions or conditions herein to the contrary, the attached Staff Report and its Exhibits ‘A’, ‘B’,and ‘C’ are incorporated and made a part of this Resolution. It is required that the Exhibits ‘B’ and‘C’ be complied with and implemented in a manner consistent with the approved use and otherconditions of approval. Such exhibits for which this permit has been granted shall not be changedor amended except pursuant to a subsequent amendment to the permit or new permit as mightotherwise be required or granted pursuant to the terms of Title 25 of the Laguna Beach MunicipalCode.
Section 10: Grounds for Revocation or Modification. Failure to abide by and faithfullycomply with Exhibits ‘B’ and ‘C’ attached to the granting of the proposed project may constitutegrounds for revocation or modification of the permit.
Section 11: Right of Appeal and Effective Date. The applicant or any other owner ofproperty within three hundred feet of the subject property aggrieved by the Design Review Board’sdecision or by any portion of this decision may appeal to the City Council. Any appeal shall be inwritten form filed with the City Clerk within fourteen calendar days of the decision and shallspecifically state each and every ground for the appeal and be accompanied by payment of therequired appeal fee. If no appeal is filed timely, the Design Review Board decision will be effective14 calendar days after the date of the decision.
Section 12: For the foregoing reasons and based on the information and findingsincluded in the Staff Report, Minutes and records of proceedings, the Design Review Board of theCity of Laguna Beach hereby approves the proposed project, subject to the conditions of approvaland plans in the attached Exhibits ‘B’ and ‘C’.
PASSED on September 9,2021, by the following vote:
AYES:NOES:ABSENT:ABSTAIN:
Page 2 of 3
ATTEST: ______________________
Louis Weil, Chair
Russell W. Bunim, AICP, Zoning Administrator
Page 3 of 3
EXHIBIT ‘A’
GENERAL PLAN GOALS AND POLICIES CONFORM (Y, N OR N/A)Land Use Element (LU) Policy 2.10 Maximize thepreservation of coastal and canyon views (consistentwith the principle of view equity) from existing Yes, refer to Design Review Criterion No. 16 above.properties and minimize blockage of existing publicand private views.LU Element Action 7.3.4 Require newdevelopment to assure stability and structuralintegrity, and neither create nor contributesignificantly to erosion, geologic stability, or Yes, the City’s hydrology consultant reviewed thedestruction of the site or surrounding area or in any project’s preliminary hydrology report andconceptually approved the project.way require the construction of protective devicesthat would substantially alter natural landformsalong bluffs and cliffs.
LOCAL COASTAL PROGRAM CONFORM (Y, N OR N/A)General Plan Land Use Map, excluding Blue Yes, the proposed use is consistent with theLagoon and Three Arch Bay underlying land use designation of VLD.Land Use and Open Space/Conservation General Yes, refer to General Plan Policies Table above.Plan Elements
Yes, the proposed use is consistent with theZoning Map underlying zoning designation of R-1 Residential
Low Density.Downtown Specific Plan N/ALaguna Canyon Annexation Specific Plan N/ATitle 25 (Zoning Code) Yes, refer to Title 25 table above.Chapter 12.08, Preservation of Heritage Trees N/AOrdinance
Yes, a geotechnical consultant will reviewChapter 14.78 Geology Reports applicable geotechnical reports to ensure no
adverse impacts as a result of the project.Title 21 (Plats and Subdivision) N/A
Yes, the proposed grading is appropriate for the siteTitle 22 (Excavation and Grading) and minimizes alterations of natural landforms on
the site.Shoreline Protection Guidelines (as adopted by N/A, the site is not an oceanfront property.Resolution 88.43)Design Guidelines for Hillside Development (as N/Aadopted by Resolution 89.104)South Laguna Community Design and Landscape
N/AGuidelines (as adopted by Resolution 89.104)
LOCAL COASTAL PROGRAM CONFORM (Y, N OR N/A)Fuel Modification Guidelines (of the Safety General N/APlan Element)Summer Festival Parking Agreements N/A2004 LCP Amendment that includes Title 16 (Water N/AQuality Control)2010 Design Guidelines — A Guide to Residential Yes, refer to the discussion under the DesignDevelopment Review heading above.
EXhIBIT ‘B’CONDITIONS OF APPROVAL
Standard Conditions:I. The conditions of approval shall be and hereby are obligations of and binding upon the applicant
and his/her heirs, successors, assigns, agents and representatives. The conditions shall constitute acovenant running with and binding the land in accordance with the provisions of California CivilCode Section 1468. Failure to comply with such conditions, and each of them, and any other relatedfederal, state and local regulations may be grounds for revocation of the approval, in addition toother remedies that may be available to the City.
2. The applicable Certificate of Use and/or Certificate of Occupancy shall not be issued until City staffhas verified compliance with all conditions of approval.
3. Prior to Building Permit issuance, the owner, his architect/designer/structural engineer, andcontractor of the subject property shall sign an Affidavit of Plan Consistency, whereby the signeesaffirm that the structural plans are consistent with the Zoning Division-approved set of plans andany modification will require subsequent review and approval.
4. In the absence of specific provisions or conditions herein to the contrary, the application and allrelevant plans and exhibits are incorporated and made a part of this approval. It is required that suchplans and exhibits be complied with and implemented in a consistent manner with the approved useand other conditions of approval. Such plans and exhibits for which this approval has been grantedshall not be substantially changed or substantially amended except pursuant to a subsequent approvalas might otherwise be required or granted pursuant to the terms of Title 25 of the City of LagunaBeach Municipal Code.
5. Expiration. Coastal development permit approval shall lapse and become void six months followingthe effective date if the privileges authorized by the permit are not executed or utilized, or, ifconstruction work is involved, such work is not commenced within such two-year period anddiligently prosecuted to completion. For City-issued coastal development permits that are notappealed to the Coastal Commission, the approving authority may grant an extension of time, not toexceed an additional six-month period for due cause. Such time extension shall be requested inwriting by the applicant or authorized agent prior to expiration of the two-year period.
6. Expiration. Design review approval shall lapse and become void two years following the effectivedate if the privileges authorized by design review are not executed or utilized or, if constructionwork is involved, such work is not commenced within such two-year period and diligently pursuedto completion. The approval authority may grant a two-year extension of time and, after that initialextension of time, a final one-year extension of time. Such time extensions shall be requested inwriting by the applicant or authorized agent prior to the expiration of the beginning two-yearapproval period or a subsequently approved extension of time.
7. Reapplication Waiting Period. After denial of a project, no application for a project located on thesame parcel or building site may be filed or accepted for filing for two months.
8. Light trespass that results in glare is prohibited.
9. All outdoor lighting, including the proposed lantern-style column lights, must be hooded, fullyshielded, and aimed downward.
10. Modifications. Additions or enlargements of structures upon property for which a variance has beengranted shall not be allowed except pursuant to a subsequent variance as might otherwise be requiredor granted pursuant to the terms of Title 25 of the City of Laguna Beach Municipal Code.
11. Expiration. This approval shall lapse and become void two years following the effective date unlessa shorter approval period is specified for the project or unless: (i) A building permit is issued andconstruction is begun and diligently pursued to completion; or (ii) the Planning Commission orDesign Review Board, as applicable, grants a two-year extension of time or, after that initialextension of time, a final one-year extension of time. Such time extensions shall be requested inwriting by the applicant or authorized agent prior to the expiration of the beginning two-yearapproval period or any subsequently approved extensions of time.
Project Specific Special Conditions:
• Temporary fencing shall be provided during construction to ensure preservation of the site’s naturalwatercourse and vegetative cover.
