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HomeMy WebLinkAboutDRAFT Project DescriptionCrooked Creek Residential Subdivision Project 1 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision SECTION 2 Project Description 2.1 Project Location Regionally, the Crooked Creek Residential Subdivision Project (Project) is located in the City of Diamond Bar (City) within the eastern portion of Los Angeles County (County); refer to Figure 1, Regional Map. The surrounding jurisdictions include Pomona to the north, Chino Hills to the east, Brea and unincorporated Los Angeles County to the south, and the cities of Industry and Walnut and the unincorporated community of Rowland Heights to the west. Locally, the Project Site, which is defined as the entire 12.9-acre property, is located at the terminus of Crooked Creek Road, east of State Route 57 (SR-57), South Brea Canyon Road, and Castle Rock Road and west of Running Branch Road; refer to Figure 2, Local Vicinity Map. The Project consists of Assessor’s Parcel Number (APN) 8714-028-003 in the northwestern quarter of the United States Geological Survey (USGS) Yorba Linda, California, 7.5-minute topographic quadrangle map within Section 29, Township 2 South, Range 9 West. Regional access to the Project Site is via SR-57. Local access to the Project Site is from the existing Crooked Creek Drive. 2.2 Environmental Setting The Project Site consists of approximately 12.9 acres of undeveloped area which supports nonnative grassland as well as coast live oaks and southern California black walnut woodland. Elevations within the Project Site range from approximately 645 feet to 835 feet above mean sea level. The eastern portion of the Project Site consists of natural steep hillside terrain with gently rolling terrain on the northern portion. The western portion of the Project Site, the Proposed Developed Area, includes areas that are relatively flat and have elevations ranging from 645 feet to 720 feet above mean sea level. 2.2.1 General Plan and Zoning General Plan The general plan designation for the Project Site is Low Density Residential which allows for single-family detached residential development reaching a maximum of 3.0 dwelling units per gross acre (3.0 du/ac). Section 2. Project Description Crooked Creek Residential Subdivision Project 2 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 1 Regional Map Section 2. Project Description Crooked Creek Residential Subdivision Project 3 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 2 Local Vicinity Map Section 2. Project Description Crooked Creek Residential Subdivision Project 4 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Zoning The zoning designation for the Project Site is RL (Low Density Residential). The maximum allowed density for new residential subdivisions within this zoning district is three dwellings per gross acre. The RL zoning district is consistent with the Low Density Residential land use category of the General Plan 2040. 2.2.2 Existing Surrounding Land Uses Land uses immediately adjacent to the Project Site consist of the following: North: Single-family residences along the existing Crooked Creek Drive. East: Undeveloped area and single-family residences along Running Branch Road. South: Undeveloped area (within Los Angeles County jurisdiction) and an existing Southern California Edison (SCE) tower and associated electrical lines. West: The Brea Canyon Flood Control Channel and single-family residences along Castle Rock Road. 2.3 Project Background The original development proposal which included 16 residential lots consisting of 16 single- family residences was approved by the City Council in 2007. The property owner sold the land to Cathay View Development, LLC, in 2014, who discovered that due to the grading requirements, the development of the 16 residential lots would not be feasible. In 2018, based on input received during community meetings, the development was reduced to include 12 residential lots consisting of 12 single-family residences. In 2019, based on further geotechnical evaluations and to reduce visual impacts, the development was further reconfigured and reduced the residential lots from 12 to 11 residential lots consisting of 11 single-family residences. In addition, the expansion of Crooked Creek Drive was narrowed in the 2019 development proposal to allow reduced retaining wall heights. The reconfigured development lowered the retaining wall height from a 24-foot average to a 12-foot average on the western portion of the Proposed Development Area (i.e., the Brea Canyon Flood Control Channel side). On the eastern portion of the Proposed Development Area (i.e., the hillside), the retaining wall height was lowered from a 60-foot average to a 30-foot average. The 2019 development proposal included an incorporated access to the undeveloped area at the end of the proposed cul-de-sac of the expansion of Crooked Creek Drive. Lastly, the first floor height of the proposed single-family residences on the western portion of the Proposed Development Area was reduced ten feet. The current development proposal (the Project), reduced the total number of residential lots from 11 to 7 residential lots consisting of 7 single-family residences resulting in a development reduction of 37 percent. The total residential lot count was lowered to reduce the overall development footprint and to allow the main access road to curve away from the hillside area; thereby substantially reducing the retaining wall requirements and slope and biological impacts Section 2. Project Description Crooked Creek Residential Subdivision Project 5 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision on the eastern portion of the Project Site. The multi-tier soil nail retaining wall from the 2019 development proposal was eliminated which had impacts to the slope and required the removal of a significant number of trees. The current development proposal includes a conventional retaining wall that will be planted with trees and climbing vines at the base of the wall and trees with cascading plants on the top of the wall for screening from the street. The original development proposal in 2007 included a total of 307 trees directly impacted by development, including 220 California black walnut trees and 77 coast live oak trees. While the current design of the Project reduced the number of native trees directly impacted by the proposed development by approximately 80 percent, the Project will still impact approximately 60 [Note to Team: The number of trees is still being determined] trees that will be mitigated with replacement trees planted throughout the Project Site in both the residential lots and the onsite retained undeveloped areas. Further, the grading was also reduced from a previous total of approximately 35,000 cubic yards of grading and 20,000 cubic yards of import for the 2019 development proposal to approximately 21,270 cubic yards of grading and a potential 5,760 cubic yards of import for the current development proposal. The current development proposal will result in an overall reduction in grading of 40 percent and dirt import of 72 percent when compared to the 2019 development proposal. 2.4 Project Features The Project includes the development of seven single-family residences and associated infrastructure including a southward extension of the existing Crooked Creek Drive within the Proposed Development Area of the approximately 12.9-acre vacant Project Site. The Project consists of nine total lots: seven residential lots; one lot designated for the private roadway (i.e., southward expansion of Crooked Creek Drive); and one lot of approximately 10.4 acres of retained undeveloped area; refer to Figure 3, Site Plan and Figure 4, Vesting Tentative Tract Map. Figure 5, Vesting Tentative Tract Map Cross Sections, depicts five cross sections throughout the proposed development footprint and a cross section of the proposed southward expansion of the existing Crooked Creek Drive. Approximately 3.1 acres of the Project Site will be disturbed for development of the Project. Of the 3.1 acres, approximately 2.5 acres (the Proposed Development Area) includes development of the proposed seven single-family residences, and the southward extension of the existing Crooked Creek Drive. The remaining 0.6 acres will include hillside grading with 8-foot terrace drains and retaining walls. The proposed 10.4 acres of retained undeveloped area is located within the eastern portion of the Project Site. Table 1, Development Summary, below, provides a summary of the nine lots located within the Project Site. 2.4.1 Residential Component As shown in Table 1, the seven residential lots range in size from 7,757 square feet to 16,826 square feet. The single-family residences range in size from 3,893 square feet to 4,810 square feet up to 33’-10” in height. The residential mix includes three separate floor plans with two separate elevations per floor plan. Six of the residential lots would be located on the western side of the expansion of Crooked Creek Drive with the one residential lot located on the eastern side; refer to Section 2. Project Description Crooked Creek Residential Subdivision Project 6 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 3 Site Plan Section 2. Project Description Crooked Creek Residential Subdivision Project 7 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 4 Vesting Tentative Tract Map Section 2. Project Description Crooked Creek Residential Subdivision Project 8 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 5 Vesting Tentative Tract Map Cross Sections Section 2. Project Description Crooked Creek Residential Subdivision Project 9 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 3 for the location of the residential building footprints. The proposed architecture style for the residential homes is Italian Tuscan. The objective for this architectural character was to design an architectural style that blends into hillside conditions for flat and terraced residential lots along with exhibiting a higher sense of luxury living. The site designed enclave uses flat, terraced and large lots to articulate stepped massing, varied character of materials, defined color, and screened landscaping surrounding the Project Site. The proposed homeowner’s association would be responsible for maintenance of the expansion of the existing Crooked Creek Drive, a utility maintenance access easement, storm drain facilities, retaining walls, trees, vegetation, and the slopes. TABLE 1 DEVELOPMENT SUMMARY Lot Num ber Lot Area (Square Feet) Plan (Square Feet)Use Program 1 7,757 3,978 Single-Family Residential 5 BR/5 BA + Guest BR6/BA6, 2 PDR plus Bonus & Library, 3 car garage 2 10,439 4,810 Single-Family Residential 4 BR/4 BA + Guest BR5/BA5, 2 PDR plus Bonus & Library & Loft, 3 car garage 3 8,482 4,810 Single-Family Residential 4 BR/4 BA + Guest BR5/BA5, 2 PDR plus Bonus & Library & Loft, 3 car garage 4 16,826 3,893 Single-Family Residential 5 BR/5 BA + Guest BR6/BA6, 2 PDR plus Bonus Room, 3 car garage 5 12,526 3,893 Single-Family Residential 5 BR/5 BA + Guest BR6/BA6, 2 PDR plus Bonus Room, 3 car garage 6 10,118 4,810 Single-Family Residential 4 BR/4 BA + Guest BR5/BA5, 2 PDR plus Bonus & Library & Loft, 3 car garage 7 15,930 3,978 Single-Family Residential 5 BR/5 BA + Guest BR6/BA6, 2 PDR plus Bonus & Library, 3 car garage Lot “A” 26,114 --Private Roadway (Future Crooked Creek Drive) -- Lot “B” 452,482 -- 560,674 ------ Section 2. Project Description Crooked Creek Residential Subdivision Project 10 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Notes: BR = bedroom; BA = bathroom; PDR = powder room. SOURCE: Michael Baker International, 2020, Vesting Tentative Tract Map No. 54081, dated August 18, 2020; Bucilla Group Architecture, Architecture Design Package, August 14, 2020. 2.4.2 Roadways/Internal Circulation The Project would include a 43-foot wide southward expansion of the existing Crooked Creek Drive which would be designated as a private roadway. The Project would not include a community gate but would include private signage indicating the community is private. A 6-foot sidewalk is proposed along the western side of the proposed Crooked Creek Drive expansion. The proposed sidewalk is a southward expansion of the existing sidewalk of the existing Crooked Creek Drive. According to the Diamond Bar Parks and Recreation Master Plan (July 2011), the City’s proposed Crooked Creek Trail Head would be located offsite near the proposed sidewalk at the cul-de-sac of the proposed expansion of Crooked Creek Drive. The City will require a public access easement along the length of the proposed sidewalk to connect to the future trail head. The trail head and access point would include decomposed granite, City signage, and a shaded bench per City design standards. The trail head would serve as an access point for a future trail connection with the County’s Schabarum Trail. The proposed 8-foot wide maintenance access road and 15-foot turnaround area would be constructed north of residential lot number 1 and east of the proposed extension of Crooked Creek Drive. The maintenance access road would include a vehicular gate and be provided for SCE to access the existing electrical lines located along the fence line of the existing single-family residences. Public access would not be allowed. 2.4.3 Fencing/Retaining Walls Located at the slopes and rear yards of all residential lots would be 5-foot and 6-foot metal view fences. The Project would include new retaining walls and slope contouring to stabilize and protect the proposed single-family residences and adjacent properties. All residential lots would include 6-foot concrete masonry unit (CMU) walls with various heights above grade at the side yards. As depicted in Cross Section E-E of Figure 5, the Project includes exposed retaining walls up to 4 feet in height located within the north side of residential lot number 2 adjacent to the existing single-family residences. While the retaining wall will be slightly visible to the proposed single-family residence in residential lot number 1, the wall would not be visible to the adjacent existing single-family residence. Further, an exposed retaining wall up to 5 feet in height and visible 4 feet above grade is proposed in the rear of residential lot number 1 adjacent to the open space area. A metal view fence will be located on top of the retaining wall along the rear side of residential lot number 1 to avoid blocking the view of the slope behind the lot. On the eastern portion of the proposed expansion of Crooked Creek Drive, an exposed CMU retaining wall up to 16 feet in height with a gradual increase of X to 16 feet above ground is proposed. A proposed 7- foot exposed retaining wall is located at the south side of residential lot 7 and adjacent to the SCE property. This retaining wall has a gradual increase of 1 to 7 feet above grade as viewed from the adjacent SCE property. An 8-foot exposed retaining wall between residential lots 6 and 7 along the proposed driveway of residential lot 7 has a gradual increase of X to 8 feet above grade. On Section 2. Project Description Crooked Creek Residential Subdivision Project 11 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision the western portion of the Proposed Development Area adjacent to the Brea Canyon Flood Control Channel, a proposed exposed pile retaining veduro up to 6 feet in height has a gradual increase of X to 6 feet above grade. Refer to Figures 3 and 4 for the proposed locations of the retaining walls. Refer to Figure 6, Proposed Wall Heights, for a depiction of the gradual increases in wall heights visible above grade. [Note to Team: ESA is requesting the Applicant to prepare a figure that depicts the gradual increase in height of the walls above grade along the expansion of Crooked Creek Drive, the walls located on the north side of residential lot number 1 and 2, and the south side of Lot 7, and along the Brea Canyon Flood Control Channel. We understand the tract map and site plan depict the height of the retaining walls, but the gradual increase and visible heights above grade for each wall is not provided.] 2.4.4 Landscaping/Plant Palette The Project includes removal 1 Coast live oak, 60 California black walnut, and 4 dead trees for a total of 65 trees to be removed [Note to Team: ESA will confirm once tree information is finalized]. Per the City’s tree replacement ratio program of 3:1, the Project will provide 183 replacement trees, which the Project proposes to replace [Note to Team: Once ESA identifies the number of trees to be replaced, the applicant will determine where they will be located]. The preliminary plant palette includes a variety of trees to be planted throughout the Proposed Development Area including Brisbane box, Marina strawberry trees, Coast live oaks, and California sycamores; refer to Figure 7, Preliminary Landscape Plan. Large and medium shrubs, spreading shrubs, accent shrubs, groundcover, and climbing vine on the retaining walls are proposed located throughout the Proposed Development Area. The entry of the Proposed Development Area includes an enhanced textured vehicular paver, a 6-foot stone pilaster with concrete cap and vertical steep pin monument signage. A row of Brisbane box trees adjacent to the existing single-family residences align the proposed maintenance access road. As discussed above, the Project would include conventional retaining walls that will be planted with trees and climbing vines at the base of the wall and trees with cascading plants on the top of the wall for screening from the street. 2.4.5 Fire Protection Features and Fuel Modification Zones The Project Site is located within a very high fire hazard severity zone. [Note to Team: Please provide fire protection features that will be included within each residential home/residential lot. Need to discuss with the Fire Department. Landscaping allowed within the proposed fuel modification zones will also need to be described.] Section 2. Project Description Crooked Creek Residential Subdivision Project 12 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 6 Proposed Wall Heights (Forthcoming) Section 2. Project Description Crooked Creek Residential Subdivision Project 13 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 7 Preliminary Landscape Plan Section 2. Project Description Crooked Creek Residential Subdivision Project 14 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision 2.4.6 Water Water is provided to the Project Site by the Walnut Valley Water District (WVWD). The Project includes a connection to the existing 6-inch domestic water lines located within the existing Crooked Creek Drive. The Project is proposing 6-inch domestic water lines to be installed beneath the proposed southward expansion of Crooked Creek Drive 2.4.7 Wastewater Wastewater services for the Project Site are provided by the City. The Project is proposing to connect to the existing 8-inch sanitary sewer lines located within the existing Crooked Creek Drive. The Project is proposing 8-inch sewer lines to be installed beneath the proposed southward expansion of Crooked Creek Drive 2.4.8 Drainage/Stormwater The existing topography results in the conveyance of storm water within three drainage areas (see Figure 8). Drainage Area A encompasses 6.2 acres, located on the west side of the Project Site, and conveys storm water from east to west to the Brea Canyon Channel via surface runoff. Drainage Area B encompasses 6.9 acres, located in the southeast portion of the Project Site, and conveys storm water from southeast to northwest to a v-ditch located behind the existing residential lots along the existing Crooked Creek Drive. These flows are direct to a culvert located on the south side of the existing residential lot (north of proposed Lot 1) and conveyed to the existing Crooked Creek Drive cul-de-sac. Drainage Area C is located in the northeastern portion of the Project Site, encompasses 3.0 acres, and conveys storm water from east to northwest to a v-ditch located behind the existing residential lots along the existing Crooked Creek Drive. These flows are conveyed north to Gold Run Drive. The proposed development area will be located within Drainage Area A while no improvements are proposed within Drainage Areas B and C (see Figure 9). The proposed drainage facilities within Drainage Area A will convey storm water to storm drains and ultimately to the Brea Canyon Channel west of the Project Site. The majority of the storm water east of the proposed Crooked Creek Drive will be conveyed to a v-ditch located behind the proposed retaining wall that borders the east side of Crooked Creek Drive. Storm water entering into the v-ditch is proposed to be conveyed south to the proposed cul-de-sac and enter a 24-inch storm drain that extends the length of the proposed Crooked Creek Drive. The remaining amount of storm water east of Crooked Creek Drive will be conveyed north toward proposed Lot 1 and will either be directed to the east or west side of Lot 1 and eventually into the 24-inch storm drain along the proposed Crooked Creek Drive. Storm water entering into the proposed 24-inch storm drain along Crooked Creek Drive will be convey south from the northern portion of the proposed development area or conveyed north from the proposed Crooked Creek cul-de-sac. Storm water within the 24-inch storm drain would be directed to a 36-inch storm drain that would extend through Lot 4 and convey storm water west to Brea Canyon Channel. Storm water from the proposed development area west of Crooked Creek Drive will be conveyed to Crooked Creek Drive and eventually conveyed to the 24-inch storm drain in the northern portion of the proposed Section 2. Project Description Crooked Creek Residential Subdivision Project 15 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision development area as well as conveyed to a 12-inch storm drain extending along the backyards of the Lots 2 through 7. Storm water within the 12-inch storm drain would be conveyed to the 36- inch storm drain that extends into the Brea Canyon Channel. Furthermore, a portion of the offsite area south of the Project site conveys storm onto the Project Site and west toward Brea Canyon Channel. The project includes a v-ditch that will convey storm water to the west onto the Project Site and to a proposed storm drain in the south west corner of the Project Site. Storm water within the proposed storm drain would be conveyed into the Brea Canyon Channel. Section 2. Project Description Crooked Creek Residential Subdivision Project 16 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 8 Existing Condition Hydrology Map Section 2. Project Description Crooked Creek Residential Subdivision Project 17 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 9 Proposed Condition Hydrology Map Section 2. Project Description Crooked Creek Residential Subdivision Project 18 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision 2.5 Construction Activities and Grading Project construction would take place for approximately 12-14 months, from August 2021 through October 2022. The Project would take approximately 150 days to construct. In general, construction activities would occur between 7:00 a.m. and 7:00 p.m., Monday through Friday except on federal holidays. Construction of the seven single-family residences and associated infrastructure including a southward expansion of the existing Crooked Creek Drive and a maintenance access road would involve the use of a variety of heavy construction equipment onsite. The majority of the equipment and vehicles would be associated with the intensive earthwork, building construction and utilities installation, paving, and architectural coating. Large construction equipment including backhoes, compactors, cranes, excavators, haul trucks, pavers, and rollers would be used during the construction phase of the Project [Note to Team: Please confirm.]. Clearing and grubbing of the site includes removal of trees and vegetation. The Project would include approximately 15,510 cubic yards of cut and 21,270 cubic yards of fill resulting in 5,760 cubic yards of potential imported soil; refer to Figure 10, Preliminary Grading Plan [Note to Team: Need to confirm grading quantities.] Two portions of the Project Site show evidence of historical landslides. One landslide area, to remain undisturbed, is located within the northeastern portion of the Project Site adjacent to the existing single-family residences. The proposed onsite grading would remove and re-stabilize the second landslide area located immediately south of the adjacent existing single-family residences. This landslide area is east of the proposed southward expansion of Crooked Creek Drive where residential lot number 1 is to be developed. As discussed above, an exposed retaining wall up to 4 feet in height and 8-foot wide terrace drains are proposed in the rear of residential lot number 1 adjacent to the open space area. Section 2. Project Description Crooked Creek Residential Subdivision Project 19 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision Figure 10 Preliminary Grading Plan Section 2. Project Description Crooked Creek Residential Subdivision Project 20 ESA / D180195.00 Initial Study/Mitigated Negative Declaration October 2020 Preliminary  Subject to Revision 2.6 Project Approvals The City of Diamond Bar, as Lead Agency for the Project, has discretionary authority over the Project. In order to implement this Project, the Project will require the following approvals and permits: Approval of the Vesting Tentative Tract Map; Issuance of a Conditional Use Permit for the proposed retaining wall heights; Tree Permit; and Development Review for the design of the proposed single-family residences. In addition to the City of Diamond Bar approvals, the following approvals will be required for the implementation of the Project. [Note to Team – The following approvals will need to be confirmed during ESA’s evaluation.] Los Angeles County Flood Control District – Approval of an easement and construction of two storm drains into flood control channel. California Department of Fish and Wildlife - Section 1600, Streambed Alteration Agreement (extension of two proposed drainage lines into Brea Canyon Flood Control Channel) Regional Water Quality Control Board – Section 401 Water Quality Certification (extension of two proposed drainage lines into Brea Canyon Flood Control Channel) U.S. Army Corps of Engineers – Section 404 (extension of two proposed drainage lines into Brea Canyon Flood Control Channel)