I. SUMMARY A. INTRODUCTION B. THE ENVIRONMENTAL REVIEW PROCESS

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1 I. SUMMARY A. INTRODUCTION This summary is intended to highlight major areas of importance in the environmental analysis, for use by decision makers and the public, and to provide the information required per Section of California Environmental Quality Act (CEQA) and the CEQA Guidelines. The summary includes a discussion of the environmental review process, a description of the proposed project, requested actions from the City of Los Angeles, areas of known controversy and issues to be resolved. A summary of the potential environmental impacts that could occur as a result of the proposed project as well as alternatives to the proposed project, their level of significance, mitigation measures and level of impact after mitigation are also included in this chapter. B. THE ENVIRONMENTAL REVIEW PROCESS CEQA requires that an environmental review be conducted for activities and approvals that involve discretionary actions. CEQA applies to all California government agencies at all levels, including local agencies; regional agencies; and state agencies, boards and commissions. An Environmental Impact Report (EIR) is an informational document required by CEQA when substantial evidence exists that a project may have a significant physical environmental effect. The EIR is intended to provide information to decision makers, agency staff and the public about (1) the potential environmental impacts of a proposed project, (2) ways in which the significant effects of a project might be minimized or avoided, and (3) alternatives to the project which could reduce or avoid the significant impacts associated with the project. CEQA applies to projects for which a governmental agency can use its judgment or discretion in deciding whether to carry out or approve the project. The public agency that has the principal responsibility for carrying out or approving the project is termed the Lead Agency. For the purpose of this EIR, the City of Los Angeles City Planning Department is the Lead Agency. This EIR will also be used by other agencies in their decision-making processes. Responsible Agencies include any public agencies, other than the Lead Agency, that have discretionary approval power over the project. Trustee Agencies are those state agencies that have jurisdiction by law over natural resources held in trust for the people of the State of California. Additionally, Reviewing Agencies includes those agencies that do not have discretionary power over the project but that are expected to review the EIR for adequacy and accuracy. The initial steps of the environmental review process are to determine whether CEQA applies and whether an EIR is required. For this project, the City Planning Department determined that CEQA did Impact Sciences, Inc. I-1 Hidden Creeks Estates Draft EIR April 2008

2 apply and, after review of the project indicated the possibility of significant environmental impacts, the preparation of an EIR was determined to be necessary. As a first step of the EIR process, the Lead Agency distributes a Notice of Preparation (NOP). The NOP is intended to solicit input from responsible agencies and other interested parties. The City Planning Department circulated an NOP for the proposed project on August 17, 2005, beginning a 30-day review period. Written comments were received from agencies and also received from interested individuals and community groups in response to this NOP. The 30-day public scoping period began on March 13, 2006 and ended on April 11, During the scoping period, comments from federal, state, regional and local public agencies and organizations, as well as from individuals and community members were received. Copies of the NOP and Initial Study are included in Appendix I, and copies of all letters received during the scoping period are included in Appendix I of this Draft EIR. This EIR is being circulated for a 45-day public review period. During this public review period, written comments concerning the adequacy of the document may be submitted by any interested person and/or affected agency to the City of Los Angeles Department of City Planning; 6262 Van Nuys Boulevard, Suite 351; Van Nuys, CA 91401; Attn: Nicholas Hendricks, City Planning Associate. Following the public review period, written responses will be prepared for comments submitted in writing during the public review on environmental issues in the Draft EIR, provided that such comments raise environmental issues. At least 10 days prior to a hearing to certify the Final EIR, proposed responses to comments from public agencies on the Draft EIR will be sent to those agencies. The Final EIR will be submitted to the Planning Commission and the City Council, which will determine whether to certify the document as reflecting the City s independent judgment and having been properly prepared in accordance with CEQA. No aspect of the proposed project will be approved until after the Final EIR is certified. C. DOCUMENT ORGANIZATION This Draft EIR is organized into the following four sections. I. Summary presents an overview of the significant effects of the project, proposed mitigation and alternatives. II. Project Description presents a description of the proposed project, including the objectives, location and characteristics of the project. Impact Sciences, Inc. I-2 Hidden Creeks Estates Draft EIR

3 III. General Description of Environmental Setting includes a general overview of the existing environmental characteristics of the area to help orient the reader. IV. Environmental Impact Analysis contains analysis of each of the environmental topics addressed in this EIR. Each topic is addressed in separate subsections. The environmental topics addressed in this EIR include the following: Aesthetics and Visual Resources Air Quality Biological Resources Cultural Resources Geology Hazards and Hazardous Materials Water Resources Land Use Noise Population and Housing Public Services Transportation Public Utilities V. Growth Inducing Impacts provides discussion of the ways in which the project could foster economic or population growth. VI. Project Alternatives provides analysis of alternatives to the project. As required by the CEQA Guidelines, a discussion of the reasons for selection of the alternatives analyzed is provided with a comparative analysis of each alternative with the project. VII. Effects Found Not to be Significant provides an overview of the issues determined not to be significant through the Initial Study process. Impact Sciences, Inc. I-3 Hidden Creeks Estates Draft EIR

4 VIII. Significant Irreversible Environmental Changes IX. Preparers; Persons Consulted and References lists all documents and persons contacted that were used as a basis of information for the EIR and provides a list of all persons and organizations contributing to the preparation of the EIR. Appendices to this EIR include the NOP, comments received on the NOP and various supporting technical studies and data summarized in this EIR. D. LOCATION AND BOUNDARIES The Hidden Creeks Estates project site is located in the northwestern portion of Los Angeles County, and immediately northwest of the existing Porter Ranch community. The Hidden Creeks Estates project site is also located in the northern part of the San Fernando Valley in the foothills of the Santa Susana Mountains. The site is bound by the Santa Susana Mountains to the north and east, and the Simi Hills to the west. Regional access is provided to the project site from the Ronald Reagan Freeway (Highway 118), an east-west freeway, and from the San Diego Freeway (I-405), a north-south freeway. Local access to the project site is currently provided via Browns Canyon Road, located north of Highway 118 and west of the existing Porter Ranch community. Primary access to the project site would be provided by a proposed extension of Mason Avenue from its current terminus at the northwest edge of Porter Ranch. This extension of Mason Avenue would be located in an easement granted to the City of Los Angeles between Porter Ranch and the project site. As part of the project, the 285-acre site would be annexed into the City of Los Angeles, and the Chatsworth-Porter Ranch Community Plan would be amended to include the project area. E. BRIEF SUMMARY OF THE PROPOSED ACTION The project applicant seeks to annex into the City of Los Angeles and develop the 285-acre Hidden Creeks Estates project site in the northwestern portion of Los Angeles County, immediately to the west of the community of Porter Ranch. The project is comprised of the following five components: (1) residential lots, (2) a public park, (3) open space, (4) an equestrian facility and trails component, and (5) access and circulation improvements. 1. Residential Lots The proposed project design would result in the subdivision of approximately 158 acres into 188 single-family residential lots with 163 single-family residential and 25 equestrian residential lots. The 25 equestrian residential lots would be located immediately adjacent to the equestrian facility to serve as Impact Sciences, Inc. I-4 Hidden Creeks Estates Draft EIR

5 a transition zone from the equestrian facility and the non-equestrian residential lots. 127 acres of the project site would be maintained as permanent open space. The remaining 2. Public Park Implementation of the proposed project would include the construction a public park on approximately 15.5 acres in the northeastern portion of the Hidden Creeks Estates project site. Park amenities could include, but would not be limited to, baseball and softball fields, soccer fields, basketball courts, tennis courts, a children s playground, and walking trails and paths. 3. Open Space The proposed project would develop approximately half of the project site with single-family residences, an equestrian facility, and a public park, while the remaining 127 acres would be preserved as open space. The envelope of open space surrounding the project would buffer the proposed residential development from the existing community of Porter Ranch to the east and south and would complement adjacent open space areas, including the Michael Antonovich Parkland, which lies just beyond the northern and western boundaries of the project site. 4. Equestrian Facility and Trails As part of the proposed project, the applicant would construct a new equestrian facility to replace the existing equestrian facility located in the southern portion of the project site. The current operators of the existing Mountain Meadows Equestrian Center would operate the new equestrian center. The proposed equestrian facility would be located on approximately 15.8 acres in the southern portion of the project site. Access to the equestrian facility would be provided via both Browns Canyon Road to the south and via internal residential streets within the Hidden Creeks Estates community. As proposed, the equestrian facility would accommodate up to 100 horse stalls, 30 trailer storage stalls, an arena, a hot walker, two wash racks, a caretaker house, a manager house, and 30 parking spaces. Equestrian trails would be provided throughout the project site. One equestrian trail along the western edge of the project site would continue connections to trails to the north and west of the site and provide linkages from existing communities to parklands beyond the project site. 5. Access and Circulation Improvements Primary access to the project site is proposed via a new roadway extending from the current northern terminus of Mason Avenue and connecting to the northeastern corner of the Hidden Creeks Estates project site, near the proposed park. The road would traverse through an easement to be granted to the Impact Sciences, Inc. I-5 Hidden Creeks Estates Draft EIR

6 City of Los Angeles by the Southern California Gas Company, the owner of the property located northeast of the project site and northwest of Porter Ranch. The right-of-way for the roadway would be approximately 50 feet wide. Browns Canyon Road, located south of the project site, would provide secondary emergency access to the site and the surrounding area. To facilitate the use of Browns Canyon Road for secondary emergency access, the roadway would be widened in fourteen locations south of the project site. Public access to the equestrian facility would also be provided via Browns Canyon Road. A staging area that could accommodate trailers and vehicles would be located near the equestrian facility and would double as a staging area for fire trucks, including a fire hydrant for fire suppression. Project residents would access the equestrian facility internally, parking off of internal streets at the southern edge of the property. 6. Project Construction Access to the site during construction would be provided by Browns Canyon Road, which would be improved with turnouts in 14 locations starting north of De Soto Avenue. Construction of the proposed project would occur over approximately 24 months and have 4 phases: (1) site clearing, (2) site grading; (3) utilities undergrounding, and (4) asphalt concrete paving. Construction is estimated to begin in early 2009 and be complete by the year The first phase of project construction (site clearing) would involve clearance of vegetation along the proposed Mason Avenue extension, demolition of the existing structures on the project site, and the clearing of vegetation on the project site. The second phase of construction (site grading) would involve the grading of the 158-acre development area and the grading of the Mason Avenue extension. The remaining 127 acres would remain undisturbed during site grading and throughout project construction with the exception of limited grading adjacent to the residential lot lines in the northwest corner of the project site for slope stabilization. This area would be re-vegetated with native plant species following this grading activity. Upon completion of site grading, utilities would be built in the proposed streets. Upon completing utility infrastructure installation, the site would be paved with asphalt concrete paving. 7. Annexation The Hidden Creeks Estates project site is currently located in an unincorporated portion of Los Angeles County. Implementation of the proposed project requires an amendment to the City of Los Angeles Sphere of Influence for the City of Los Angeles, as approved by the County of Los Angeles Local Agency Formation Commission (LAFCO), as well as the annexation of the property into the City of Los Angeles. The City is currently in the process of amending its Sphere of Influence to include unincorporated portions of the San Fernando Valley, including the project site (Sphere of Influence Amendment Impact Sciences, Inc. I-6 Hidden Creeks Estates Draft EIR

7 CF ). Upon annexation of the project site into the City of Los Angeles, the site would fall within the Chatsworth-Porter Ranch Community Plan Area. Therefore, accompanying the annexation of the site into the City of Los Angeles would be a Citywide General Plan and Community Plan amendment to correspond with the proposed land use and zoning designations of the project. F. PROJECT OBJECTIVES The project applicant seeks to annex into the City of Los Angeles and develop the 285-acre Hidden Creeks Estates project site in the northwestern portion of Los Angeles County, immediately to the west of the community of Porter Ranch. More specifically, the objectives of the Hidden Creeks Estates project are: To implement the recommendations contained in the Chatsworth-Porter Ranch Community Plan by annexing a portion of the 12,800-acre area adjacent to the City of Los Angeles, north of the communities of Chatsworth, Porter Ranch and Granada Hills, into the City of Los Angeles and within the Chatsworth-Porter Ranch Community Plan Area; To provide new residential units to the Chatsworth-Porter Ranch Community Plan Area that reinforce the prevailing community character; To design economically and attractively designed housing and public facilities to accommodate the growing population within the City of Los Angeles; To complement and enhance the equestrian orientation of the community; To design a project with density and intensity respectful of the Chatsworth-Porter Ranch Community Plan policies related to development in a hillside area; To permanently preserve views, opens space, and the unique topography and vegetation in the Chatsworth-Porter Ranch Community Plan Area; To provide a facility for training and boarding horses and ample recreational opportunities within an equestrian facility which serves the surrounding community; To provide an additional neighborhood park; To enhance fire protection on the site by extending water provision facilities and Fire Department access to the site; and To maintain and provide linkages with existing equestrian trails. G. ACTIONS REQUESTED The Los Angeles Department of City Planning is acting as lead agency as defined by CEQA for environmental review of this project. LAFCO, the California Department of Fish and Game (CDFG), and Los Angeles Regional Water Quality Control Board (LA RWQCB) are responsible agencies as defined by Impact Sciences, Inc. I-7 Hidden Creeks Estates Draft EIR

8 CEQA. Upon certification of the EIR by the City of Los Angeles, a variety of discretionary and ministerial actions may be required, including, but not limited to: City of Los Angeles General Plan Amendment to include the annexed property; Zone Change (including height district and H designation); Pre-Annexation and Development Agreement; Vesting tract map for subdivision purposes; Amend the Chatsworth-Porter Ranch Community Plan Amendment to designate the site: Minimum Density, Very Low Density I, Very Low Density II, and Open Space; Conditional Use Permit to allow for equine boarding at the equestrian facility in the RA zone; Zoning Administrator Determination (ZAD) to allow retaining walls at specified heights within the required yards; Zoning Administrator Adjustment (ZAA) to allow the location of residential buildings within 35 feet of an equine use; All other building and construction related permits granted under the authority of the Department of Building and Safety; and Other approvals as necessary. 1. Los Angeles Local Agency Formation Commission The Los Angeles Local Agency Formation Commission (LAFCO) is a Responsible Agency under CEQA for the proposed project. LAFCO will consider the analysis contained in this EIR when considering the following discretionary and/or ministerial actions: Annexation of the project site into the City of Los Angeles 2. California Department of Fish and Game The California Department of Fish and Game (CDFG) is a Responsible Agency under CEQA for the proposed project. CDFG will consider the analysis contained in this EIR when considering the following discretionary action: California Department of Fish and Game permit Impact Sciences, Inc. I-8 Hidden Creeks Estates Draft EIR

9 3. Los Angeles Regional Water Quality Control Board The LA RWQCB is a Responsible Agency under CEQA for the proposed project. consider the analysis contained in this EIR when considering the following discretionary action: LA RWQCB will Regional Water Quality Control Board water quality certification under Section 401 H. AREAS OF CONTROVERSY AND ISSUES TO BE RESOLVED Comments received from the public, agencies and interested parties on the circulated NOP highlighted environmental issues of concern regarding the proposed project. Review of comments received during the NOP circulation period indicated areas of controversy, such as aesthetics, agricultural resources, air quality, biological resources, cultural resources, geology and soils, the potential presence of hazards and hazardous materials, hydrology and water quality, land use and planning, mineral resources, public services, recreation, noise, utilities and service systems, transportation and traffic, population and housing, and annexation. All of the areas of controversy are addressed in this EIR. I. SUMMARY OF ENVIRONMENTAL IMPACTS 1. Aesthetics and Visual Resources Aesthetics Project Impacts The residential structures would be clustered on the more level and disturbed plateau of the terrain while the steeper portions adjacent to the two creeks on the site would be preserved in their natural state. The permanent open space on site would also serve to create an urban buffer or limit line whereby no additional development or urbanization would occur. Therefore, the project design strategy would reduce the amount of natural open space graded and affected by the project, would minimize impacts to the creeks on the site, and would be consistent with development standards set by the Chatsworth-Porter Ranch Community Plan to preserve the natural and undeveloped hillside and mountainous terrain. The permanent conversion of open space area to a residential neighborhood, the associated grading activity, and the removal of protected trees on the site would permanently alter the visual character of the site. The physical removal of these trees constitutes a significant impact, as discussed in detail in Section IV.C, Biological Resources. However, the impact would be reduced to a less than significant level with implementation of mitigation measure MM-BIO-7, which requires that each tree removed be replaced with two trees of the same type, each 15 gallons in size. Impact Sciences, Inc. I-9 Hidden Creeks Estates Draft EIR

10 The single-family residences would reflect the style and design of single-family homes typical to Southern California and would not exceed two stories, or 36 feet, in height. The landscaping strategy, the project site s proximity and connectivity to the Porter Ranch community, utilization of the cluster design concept, and implementation of MM-BIO-7 would reduce the degree to which the proposed project would contrast with the aesthetic resources and character of the existing site and surrounding hillsides. Therefore, the impact associated with the integration of the project site into the aesthetic character of the project area would be less than significant. The architectural styles and building materials have not yet been determined for the project. However, they would be consistent with the styles and materials found in the adjacent Porter Ranch community. All signage and aboveground utility infrastructure would be subject to the height limits according to the applicable zoning codes. Since the scale of the buildings would be consistent with the Porter Ranch community, Section IV.A.1, Aesthetics determined that the aesthetic impact of the proposed zone change on the project site would be less than significant. The proposed project would result in the development of an area representing less than 15 percent the size of the adjacent Porter Ranch Specific Plan Area. Therefore, the project would represent an incremental extension of preexisting and pending development in the Santa Susana foothills. Based on this as well as the project s preservation of surrounding open space and the project s design consistency with the Porter Ranch community, project impacts based on the degree to which the project would contribute to the area s aesthetic value would be less than significant. Section IV.A.1, Aesthetics evaluated the project s consistency with policies, guidelines, and regulations specifically related to aesthetics contained within the City of Los Angeles General Plan, the Chatsworth- Porter Ranch Community Plan, and the Los Angeles Municipal Code. The Draft EIR determined that the proposed project would not conflict with any applicable guidelines or regulations specifically related to aesthetics. Therefore, impacts were determined to be less than significant. Mitigation Measures Implementation of the proposed project would affect the aesthetic character of the project site. The removal of protected trees due to grading activity would constitute a significant impact. However, implementation of MM-BIO-7, within Section IV.C, which outlines the requirements of the Tree Replacement Program, would reduce the aesthetic impact to a less than significant level. Impact Sciences, Inc. I-10 Hidden Creeks Estates Draft EIR

11 Cumulative Impacts The proposed development would alter approximately 158 acres of the existing site from mostly unimproved land to a suburban residential neighborhood. The project would be located approximately 2,000 feet west of the intersection of Sesnon Boulevard and Mason Avenue along the western boundary of the Porter Ranch community, which is currently developed with single-family residences and additional development will be completed associated with the buildout of the Porter Ranch Specific Plan. Existing development along the Santa Susana foothills is contiguous with development across the San Fernando Valley. Planned development within the foothills, including the buildout of the Porter Ranch Specific Plan, in addition to the proposed project, represents a marginal increase in development within the Chatsworth-Porter Ranch Community Plan Area and the Santa Susana foothills due to the proximity and quantity of existing development. The visual characteristics associated with each new development would be regulated by the Chatsworth-Porter Ranch Community Plan. Therefore, the proposed project in conjunction with additional development within the Community Plan Area would result in a less than significant cumulative impact regarding aesthetics. On a more local level, upon buildout of the Porter Ranch Specific Plan, the developed area in Porter Ranch would expand westward and would nearly abut, with the exception of a small open space corridor along Mormon Canyon Creek, the project site. The proposed project would result in the development of an area representing less than 15 percent the size of the Porter Ranch Specific Plan Area. Therefore, the project would represent an incremental extension of preexisting and pending development in the Santa Susana foothills and the project would not result in a cumulatively considerable contribution to development in the Porter Ranch area. Adverse Effects Despite the permanent conversion of open space area to a residential neighborhood, the use of the cluster concept, the concentration of development on the primarily disturbed portion of the site, preservation of open space, and implementation of tree planting mitigation would reduce the removal of features which contribute to the area s visual character and would reduce the amount of natural open space to be graded. The landscaping strategy and the project s consistency and connectivity with the Porter Ranch community would facilitate the project s aesthetic integration into the project area. Finally, the project would represent a marginal increase in development within the area due to the vast quantity and proximity of existing and planned development within the Santa Susana foothills and the greater Chatsworth-Porter Ranch area. Based on this, the project would result in a less than significant impact to the natural visual character of the Santa Susana Mountain region as well as to the visual character of adjacent communities such as Porter Ranch. Impact Sciences, Inc. I-11 Hidden Creeks Estates Draft EIR

12 Obstruction of Views Project Impacts As discussed in Section IV.A.2, Obstruction of Views, the project site does have locations along scenic highways, roadways, recreational trails and/or bicycle routes from which the site can be either partially or fully visible. Short-range views of the project site would be more drastically altered with implementation of the proposed project. Mid- and long-range views of the project site would be slightly altered; however, construction of the proposed project would merely extend the existing suburban character of Porter Ranch slightly west to include the project site. Given the site s immediate adjacency to the Porter Ranch community, implementation of the proposed project would not alter the existing visual character of the site or surrounding area such that significant adverse impacts to views would occur. Mitigation Measures Impacts would be less than significant, and no mitigation measures are required. Cumulative Impacts Implementation of the proposed project in combination with identified related projects does have the potential to cumulative affect views and visual changes in the surrounding area, however, not to a significant level. The identified related projects include the construction of either new, or the expansion of existing residential neighborhoods within the general vicinity of the Hidden Creeks Estates project site. As such, build out of cumulative development would introduce more residences and thus expand the suburban character of the hillsides in the northern portion of the San Fernando Valley. While the project would contribute to the cumulative expansion of the development in the hills, the project site represents a small portion of the panoramic viewshed of the entire hillside and the Santa Susana Mountains. Additionally, development exists immediately up to the site on the east, and with implementation of the proposed project, a permanent open space buffer would be put in place to the west and north such that the developed area on the project site would represent the permanent edge of urban development in the City of Los Angeles and in the hills. As such, no significant cumulative impacts would result with implementation of the proposed project and cumulative projects. Adverse Effects The project would result in a less than significant impact to views of the project site and surrounding area. Impact Sciences, Inc. I-12 Hidden Creeks Estates Draft EIR

13 Nighttime Illuminations Project Impacts As discussed in Section IV.A.3, Nighttime Illuminations, there are potentially significant impacts during construction and operation of the proposed project relating to nighttime illuminations. The nighttime illumination on the project site is minimal and is primarily generated by uses associated with the single-family residence, the equestrian facility, and ranching operations. Potential light-sensitive land uses existing in the project vicinity include the residences within the Porter Ranch community, the undeveloped natural open spaces surrounding the project site, scenic vista points such as the ones along the Oat Mountain ridgeline above the project site, and horsekeeping areas east of the project site. If not properly implemented, lighting used for security purposes during project construction has the potential to spill onto these sensitive land uses and result in a significant impact. However, mitigation measures would prevent the trespass of light onto light-sensitive areas during construction. With implementation of these mitigation measures and temporary usage of nighttime security lighting during construction, the impact to light-sensitive areas outside the project boundary would be less than significant. Additionally, the proposed project would introduce new permanent sources of lighting to the project site and project area. The various light sources have the potential to spill over onto or otherwise affect adjacent light-sensitive uses including the residences within the Porter Ranch community, the undeveloped open space surrounding the project site, scenic vista points, and horsekeeping areas. Since the project would introduce new permanent light sources within a previously undeveloped area of the Santa Susana foothills, the potential exists for project generated light to spill off the project site and affect light-sensitive uses, resulting in a significant impact. However, mitigation measures would reduce the potential for light spillover by incorporating shielding and screening, projecting light sources downward, limiting the use of park and equestrian facility lighting, and lowering lighting intensity. Furthermore, the project would comply with the Los Angeles Municipal Codes regarding parking lot lighting, street lighting and outdoor lighting. With Code compliance and the incorporation of mitigation, the potential for light spillover to affect light-sensitive land uses would be reduced to a less than significant level. Mitigation Measures Implementation of the following mitigation measures would reduce potentially significant visual resource impacts from the Hidden Creeks Estates project to a less than significant level. MM-NIGHT-1 The use of security lighting during project construction shall be limited to only those locations on the construction site requiring illumination. Impact Sciences, Inc. I-13 Hidden Creeks Estates Draft EIR

14 MM-NIGHT-2 All security lights shall be properly shielded and projected downwards during construction such that light is directed onto the project site only. MM-NIGHT-3 Prior to the issuance of a grading permit, the project applicant shall develop a lighting plan that shall be subject to approval by the City of Los Angeles Planning Department. In the plan, all lighting shall be downcast luminaries with light patterns shielded and directed away from adjacent open space areas. Mercury vapor and halide lighting shall not be used on the perimeter of the developed areas and in areas adjacent to undeveloped open space. Security lighting throughout the project shall be controlled by motion detectors, to limit light shine to necessary periods. MM-NIGHT-4 High pressure sodium and/or cut-off fixtures shall be used instead of typical mercury-vapor fixtures for outdoor lighting. MM-NIGHT-5 The lighting plan shall provide structural and/or vegetative screening from sensitive uses. MM-NIGHT-6 The lighting plan shall design exterior lighting to conform illumination to the project site and/or to areas which do not include light-sensitive uses. MM-NIGHT-7 The hours of operation of outdoor lighting at the equestrian facility shall be restricted to the hours of 6:00 AM to 10:00 PM. The hours of operations of outdoor lighting at the public park shall be restricted to the hours of 7:00 AM to 10:00 PM. Cumulative Impacts The proposed development would introduce new permanent sources of light to the project site where presently undeveloped land is located. The project would be located approximately 2,000 feet west of the intersection of Sesnon Boulevard and Mason Avenue along the western boundary of Tract in the Porter Ranch community which is currently developed with single-family residences. However, additional development has been proposed as part of the Porter Ranch Specific Plan. Upon buildout of the Porter Ranch Specific Plan Area the developed area in Porter Ranch would expand westward and would abut the project site. Thus, ambient illumination levels are anticipated to increase in the project area. Therefore, the proposed project in combination with adjacent development would result in an increase in nighttime illumination such that a significant cumulative impact to nighttime illumination. Impact Sciences, Inc. I-14 Hidden Creeks Estates Draft EIR

15 Adverse Effects Impacts associated with construction lighting would be less than significant with incorporation of MM-NIGHT-1 and MM-NIGHT-2. Additionally, operation of the proposed project would result in less than significant impacts to light-sensitive uses with implementation of MM-NIGHT-3 through MM-NIGHT-7, which would reduce the potential for light spillover as well as the intensity and use of nighttime light. Cumulative impacts to ambient nighttime illumination due to the buildout of the proposed project and related projects would be less than significant. Planned development within the foothills represents a marginal increase in development within the Chatsworth-Porter Ranch Community Plan Area and the Santa Susana foothills due to the proximity and quantity of existing development. Thus, ambient illumination levels are anticipated to increase in the project area, but would not result in a cumulative significant impact due to the present extent of nighttime illumination within the Chatsworth- Porter Ranch area and entire San Fernando Valley. 2. Air Quality Project Impacts As discussed in Section IV.B, Air Quality, emissions generated during all phases of project construction are expected to exceed the South Coast Air Quality Management District (SCAQMD) threshold for emissions of oxides of nitrogen (NOX). In addition, the project is expected to exceed the volatile organic compounds (VOC), particulate matter 10 microns or smaller (PM10), and particulate matter 2.5 microns or smaller (PM2.5) SCAQMD thresholds during the site grading phase. Since construction emissions for NOX, PM10, and PM2.5 exceed the SCAQMD thresholds, construction impacts associated with development of the project are considered significant. LST analysis contained in Section IV.B, Air Quality shows that maximum carbon monoxide (CO), PM10, and PM2.5 concentrations are not anticipated to exceed the threshold of significance established by SCAQMD at the nearest residential receptor to the project site with respect to the localized significance thresholds (LST) methodology. The impacts demonstrate that PM10 emissions would not exceed the limitations in SCAQMD Rule 403. The maximum Nitrogen Dioxide (NO2) concentration, however, would exceed the threshold of significance. While the maximum modeled NO2 concentration is anticipated to exceed the LST threshold, the actual concentrations could differ from the results presented in Section IV.B Air Quality. The majority of emissions that would occur as a result of the proposed project are generated by the operation of vehicular sources, with the exception of consumer products for emissions of VOC. Emissions from on-site uses comprise only a small portion of the overall emissions inventory associated Impact Sciences, Inc. I-15 Hidden Creeks Estates Draft EIR

16 with the proposed development. Operational emissions associated with the complete build out and operation of the project would not exceed SCAQMD thresholds. Therefore, operational emissions are considered less than significant. A project-specific CO hotspots analysis was conducted and it was demonstrated that the project s CO emissions would not exceed the state or federal 1-hour or 8-hour standards due to the emissions from the cumulative traffic, including that from the proposed project. No significant CO hotspot impacts would occur to sensitive receptors in the vicinity of these intersections. As a result, no significant project-related impacts would occur relative to projected CO concentrations. As discussed in Section IV.J, Population and Housing, the population growth associated with the annexation of the proposed project would still be within the Southern California Association of Governments (SCAG) growth projections for the City of Los Angeles in the near term and long term, and therefore the project is consistent with the 2003 Air Quality Management Plan (AQMP). As determined in Section IV.B, Air Quality, the proposed project would not jeopardize attainment of state and federal ambient air quality standards in the Chatsworth-Porter Ranch Community Plan Area or the Basin. The proposed residential uses on the site would not generate objectionable odors. The surrounding community currently possesses an equestrian-orientation; therefore, horse-related odors would typically not be considered objectionable by most local residents. Wastes would be disposed of in accordance with any applicable requirements. Consequently, no significant impacts from such odors are anticipated. As indicated in Section IV.B, Air Quality and Section IV.F, Hazards and Hazardous Materials, the project would not have hazardous materials on site and would not be a source of toxic air contaminants regulated by the SCAQMD, state, or federal government, except as a result of normal use of household and consumer products, architectural coatings, and similar products. Therefore, no significant impacts are anticipated with respect to the hazardous materials or emissions. Mitigation Measures Construction Impacts MM-AQ-1 The construction contractor shall develop a Construction Traffic Emission Management Plan to minimize emissions from vehicles including, but not limited to, scheduling truck deliveries to avoid peak hour traffic conditions, consolidating truck deliveries, and prohibiting truck idling in excess of 5 minutes. Impact Sciences, Inc. I-16 Hidden Creeks Estates Draft EIR

17 MM-AQ-2 The construction contractor shall ensure that the use of all construction equipment is suspended during first-stage smog alerts. MM-AQ-3 The construction contractor shall enforce the use electricity or alternate fuels for on-site mobile equipment instead of diesel equipment to the extent feasible. MM-AQ-4 The construction contractor shall ensure that all construction equipment is maintained by conducting regular tune-ups according to the manufacturers recommendations. MM-AQ-5 The construction contractor shall ensure the use of electric welders to avoid emissions from gas or diesel welders, to the extent feasible. MM-AQ-6 The construction contractor shall ensure the use of on-site electricity or alternative fuels rather than diesel-powered or gasoline-powered generators to the extent feasible. MM-AQ-7 Prior to use in construction, the project applicant will evaluate the feasibility of retrofitting the large off-road construction equipment that will be operating for significant periods. Retrofit technologies such as particulate traps, selective catalytic reduction, oxidation catalysts, air enhancement technologies, etc., will be evaluated. These technologies will be required if they are verified by the Air Resources Board (ARB) and/or the U.S. Environmental Protection Agency (EPA) and are commercially available and can feasibly be retrofitted onto construction equipment. MM-AQ-8 The construction contractor shall ensure that traffic speeds on all unpaved roads are reduced to 15 miles per hour or less. MM-AQ-9 The construction contractor shall ensure that active sites are watered at least three times daily during dry weather. MM-AQ-10 The construction contractor shall schedule all construction activities that affect traffic flow during off-peak hours (e.g., between 7:00 PM and 6:00 PM and between 10:00 AM and 3:00 PM). Operational Impacts The project may results in potentially localized significant NO2 impacts. Therefore, the mitigation measures identified above are required to be implemented as part of the project. Impact Sciences, Inc. I-17 Hidden Creeks Estates Draft EIR

18 Cumulative Impacts The SCAQMD has not identified thresholds to which the total emissions of all cumulative development can be compared. Instead, the SCAQMD s methods are based on performance standards and emission reduction targets necessary to attain the federal and state air quality standards identified in the AQMP. As analyzed in Section IV.B, Air Quality, the growth of vehicles miles of travel (VMT) or average daily trips (ADT) ratio is less than the population ratio at project buildout in As this criterion has been met, and the project is consistent with the AQMP, there is no potential for significant cumulative impacts with respect to this criterion. The project s construction emissions would exceed the project-level threshold of significance for VOC, NOX, PM10, and PM2.5. Accordingly, the project s construction emissions, prior to mitigation, would be considered cumulatively considerable, and the cumulative air quality impact would be significant under this criterion. Adverse Effects Although the recommended mitigation measures, if feasible, would reduce the magnitude of construction emissions, no feasible mitigation exists that would reduce all of these emissions to below the SCAQMD s recommended thresholds of significance. The project s construction-related emissions of VOC, NOX, PM10, and PM2.5 are considered significant and unavoidable. The proposed project ADT ratio is less than the population ratio at project build out; therefore; the cumulative impacts are less than significant based on this criterion. However, the mitigated constructionrelated VOC, NOX, PM10, and PM2.5 emissions exceed the SCAQMD s recommended daily emission thresholds of significance for these pollutants. As the Basin is already designated as nonattainment for ozone (VOC and NOX are ozone precursors), PM10, and PM2.5, any increases in these emissions by the project are considered significant and unavoidable cumulative air quality impacts. 3. Biological Resources Project Impacts As discussed in Section IV.C, Biological Resources, botanical surveys of the Hidden Creeks project site indicate that no special-status plant species occur on the project site. Therefore, development associated with construction of the proposed project would not result in significant impacts to special-status plant species. Eighteen special-status wildlife species have the potential to occur on, or otherwise utilize, the project site. In addition, surveys of the project site have confirmed that four special-status species inhabit Impact Sciences, Inc. I-18 Hidden Creeks Estates Draft EIR

19 the site, including three CSC, the two-striped garter snake, Cooper s hawk, and southern California rufous-crowned sparrow, and one California Natural Diversity Database (CNDDB) Special Animal, the California thrasher. However, several of the special-status wildlife species that have the potential to occur on site or that have been observed on site are considered to be special-status only during specific phases of their lifecycle. Because of the high mobility of these species, and because these species are expected to utilize the project site for foraging only, direct impacts to these wildlife species would not be expected, and impacts from construction of the proposed project would be less than significant. Due the high mobility of the golden eagle and the availability of similar habitat in other locations within the vicinity of the project site, project activities would be unlikely to directly impact wintering individuals of this species. Therefore, impacts to this species from construction activities would be less than significant. Because the two-striped garter snake, which was observed on site, has been disappearing rapidly from throughout its range, and because the aquatic habitats on which they depend are subject to intense hydro-modification, impacts to this species associated with removal of on-site aquatic habitat would be potentially significant. Construction of the Hidden Creeks project would result loss of suitable nesting habitat for several special-status bird species, such as Cooper s hawk, white-tailed kite, southern California rufous-crowned sparrow, California thrasher, Bell s sage sparrow, southwestern willow flycatcher and least Bell s vireo. If these bird species were to nest on site, construction-related activities could result in the direct loss of an active nest or the abandonment of an active nest by adult birds during that year s nesting season, which would result in a significant impact. In addition construction of the Hidden Creeks project would result loss of suitable habitat for other special-status species such as silvery legless lizard, coast (San Diego) horned lizard, coastal western whiptail, San Bernardino ring-neck snake, San Diego black-tailed jackrabbit, San Diego desert woodrat, western yellow bat and Yuma myotis. Construction-related activities could result in the direct loss of individuals of the species. The loss of individuals of the species would be a potentially significant impact. The proposed Hidden Creeks project would not significantly impact locally designated species, natural habitat, or plant communities, as none are present on the project site. The project site is located on the eastern side of the Santa Susana Pass regional wildlife corridor. Direct impacts to the wildlife corridor are not expected as a result of the proposed project, and indirect impacts would not be expected to significantly affect the corridor s viability. Construction would be unlikely to result in significant impacts to wildlife movement, as most wildlife movement occurs primarily in the Impact Sciences, Inc. I-19 Hidden Creeks Estates Draft EIR

20 evening, when no construction would occur. In addition, disturbance associated with construction activities would be short-term. Therefore, impacts to regional wildlife movement/migration corridors associated with construction activities would be less than significant. On-site stream channels, as well as those stream channels impacted by construction associated with the Mason Avenue extension, that fall under the jurisdiction of the U.S. Army Corps of Engineers (ACOE) and the CDFG have been identified in the Jurisdictional Delineation for the site, included as Appendix IV.C. All riparian vegetation on the project site also qualifies to be regulated by CDFG. In addition, two wetlands that meet the ACOE definition criteria were observed on the project site or in the vicinity of offsite impact areas. A portion of the partially on-site wetland, located on the western border of the project site, would be directly impacted by project construction. The wetland located to the east of the project site, approximately 125 feet to the west of off-site impact areas associated with the Mason Avenue extension, would be indirectly impacted by grading activities required for the construction of Mason Avenue. Such grading activities would change the hydrologic regime of water feeding the wetland seep. It is expected that construction of the Hidden Creeks project would result in direct removal of both federal and state jurisdictional wetland resources. Due to the high habitat value that drainages and swales are known to provide for wildlife, and the importance of drainages in improving water quality, the proposed removal of this vegetation and these waters is considered a significant impact prior to mitigation. Development of the project site as proposed and occupancy of the proposed residences would involve an increase in human and domestic animal presence in the area, increased populations of non-native plant species, and increased stormwater runoff. Increases in such disturbances to wetlands and jurisdictional waters that remain undeveloped after project construction could result in degradation of the quality of these areas, which would be considered a potentially significant impact. Heavy equipment used during project construction would produce short-term noise increase which could temporarily affect sensitive wildlife species in the project vicinity. However, because wildlife species potentially disturbed by noise increases would likely retreat to portions of the property not under construction at the time of disturbance, and because such noise increases would be temporary, interferences associated with construction activities would not be expected to diminish the chances for long-term survival of a sensitive species, and would not be considered significant. Upon completion of construction of the Hidden Creeks project, open space lands on the property and adjacent properties to the north would remain undeveloped. Operation of the Hidden Creeks residential development would affect special-status wildlife species in those areas through indirect impacts, including: increased human and domestic animal presence (and associated noise) in the area; increased Impact Sciences, Inc. I-20 Hidden Creeks Estates Draft EIR