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HomeMy WebLinkAboutCommunity General Plan - Diamond Bar7. le i 6Z-Ah., IM PROPOSED DIAl10ND BAR COM11UNITY GE14ERAL PLAN APPROVED BY THE REGIONAL PLANNING C0124ISSION MARCH 16, 1983 A CA 0- 0 (1--k- 1� l q 2, COUNTY OF LOS ANGELRS- DEPARTMENT OF REGIONAL PLANNING'' DIM1014D BAR PLANNING ADVISORY COM ITTEE This draft community general plan was prepared by the Diamond Bar Planning Advisory Committee working in conjunction with the staff of the Department of Regional Planning. The Regional Planning Commission gratefully -acknowledges the long hours of conscientious participation by these citizens. Carol Lucero: Brenda Engdahl: Chairperson Vice Chairperson Jim Bailey Dennis Bethurum Tim Brundige Dal Cabell Tyrone Daisy Margaret Edmonds George Francis Pat Garrick Layna Han A.R. Hansen, deceased Carol Herrera Elizabeth Honer Ruth Honour Helen Juliar Ileana Liel Wes Lind Martin Shaw Robert Seiler Donald Ury John Willwerth Kenneth Zelt BOARD OF SUPERVISORS Michael Antonovich, Chairman, Fifth District Peter F. Schabarum, First District Kenneth Hahn, Second District Edmund Edelman, Third District Deane Dana, Fourth District REGIONAL PLANNING COM ISSION Delta Murphy, Chairman Norma Bard, Vice -Chairman George Lefcoe Sadie B. Clark Stanley R. Gould Betty M alcomb, Secretary DEPARTMENT OF REGIONAL PLANNING Norman Murdoch, Planning Director Anthony De Vito, Chief Deputy Director Frederick W. Jackson, Administrative Deputy COMUNITY PLANNING DIVIS1014 John Huttinger, Section Head Gerry Kam Dave Tilton GRAPHICS Johannes Kunst, Section Head Darlene Brown Diary Rowe TABLES PAGE I. LEVEL OF SERVICE DESCRIPTIONS 14 II. .HIGHWAY PLANS ......................................... 17 III. OUTDOOR NOISE ENVIRONMENT ............................. 20 IV. CURRENT 1401SE EXPOSURE ................................. 23 V. PROJECTED NOISE EXPOSURE ............................... 25 VI. EXISTING AND PROJECTED PARK NEEDS ...................... 27 MAPS PAGE I. PROPOSED LAND USE & CIRCULATION 10 II. TOPOGRAPHY ................................................. 11 III. CURRENT NOISE EXPOSURE ..................................... 19 IV. ASSESSOR'S MAP BOOKS ....................................... 22 V. PROJECTED NOISE EXPOSURE .................................. 24 VI. CONSERVATION AND RECREATION ................................ 29 TABLE OF CONTENTS PAGE I. INTRODUCTION ............................................. 1 II. GOALS ...... ..................... ......................... 4 III. LAND USE ................................................. 5 IV. CIRCULATIO14.............................................. 12 V. NOISE ..........® ......................................... 18 VI. OUTDOOR RECREATION ...................................... 26 VII. PLAN IMPLEMENTATION ...................................... 30 INTRODUCTIO14 Nature of the Community Plan The Diamond Bar Comnunity General Plan provides a framework for future development and establishes general goals and specific policies as guidelines for the extent and nature of growth. It is an element of the Los Angeles Countywide General Plan, providing greater detail and clarity on local issues and concerns than is possible through the county general plan. The community plan is comprehensive, being based on an analysis of such physical features of the community as geology, seismicity, slope, vegetation, and consideration of the social environment and its relationship to the physical environment. Study of these interrelationships provides the basis for determining the kinds of growth and development which can be accommodated. The plan. provides a long range forecast for the community to insure that the appropriate facilities will be provided. To the extent feasible, the policies enumerated in this plan shall be applicable to the contiguous, unincorporated areas of Los Angeles County, in the absence of a community general plan covering the specific areas involved, when development in those areas will cause a negative impact within Diamond Bar by reducing the criteria enumerated in this plan below the minimum levels specified. This report contains a summary of the problems and issues facing Diamond Bar and the policy recommendations developed to respond to these community concerns. Included are sections addressing land use, circulation, noise, and recreation. These sections are refinements of the respective portions of the Countywide General Plan Elements applicable to Diamond Bar. The Countywide General Plan provides the elements dealing with housing, conservation, open space, safety, seismic safety, and scenic highways. Additional information, such as ai-r quality statistics and flora and fauna inventories, are found in the Environmental Impact Report. The Diamond Bar Planning Advisory Committee The plan was developed by the Diamond Bar Planning Advisory Committee working in close conjunction with the staff of the Los Angeles County Department of Regional Planning. The committee held more than 20 public meetings between September, 1980 and June, 1982. The first few meetings were devoted to discussions of concerns of the local citizenry and background technical data which ,serve as the foundation for plan recommendations. The latter meetings consisted of lengthy discussions of policy alternatives for achieving the community goals. The committee also examined the environmental features of large vacant properties and projects propose,] for Diamond Bar to determine the most viable land use classification and resolve development conflicts. —1— -2- The Community of Diamond Bar Diamond Bar is a predominately residential community located approxi- mately 30 miles east of the Los Angeles Civic Center. The community study boundaries are contiguous with those of the Diamond Bar Municipal Advisory Council, generally extending from the City of Pomona on the north to the Firestone Boy Scout Reservation on the south. The unincorporated community of Rowland Heights and the Cities of Walnut and Industry form the western boundary while the eastern boundary consists of San Bernardino County. Diamond Bar is a typical suburban bedroom community with little commercial or industrial land. The commercial acreage primarily is developed with uses designed to serve residents of the local community. Single family residences are the predominate housing type, although multiple units have increased significantly in recent years. Problems and Issues The Planning Advisory Committee has identified the major concerns facing the residents of Diamond Bar as the following: 1. Preservation of the rural setting of Diamond Bar by minimizing alterations of the natural terrain and retaining extensive amounts of natural open space and hillside vegetation; and 2. Perpetuation of the predominately single family, detached housing stock. The population and housing stock in Diamond Bar have changed significantly in the last 10 years both in numbers and character. The recent rapid growth of Diamond Bar has consumed extensive areas of rolling foothills. To trace population growth in the Diamond Bar area it is necessary to use the Department of Regional Planning's Sub -statistical Area boundaries. The Sub -statistical Area (26.142) for Diamond Bar, as noted in the Department of Regional Planning's "Quarterly Bulletin", is larger than the Diamond Bar Community General Plan Study Area and includes 552 dwelling units that are outside the Community General Plan boundaries. The January 1, 1979 "Quarterly Bulletin" estimated the dwelling units and population of the Diamond Bar Sub -statistical Area (26.142) at 7,288 and 27,698 respectively. This represents over a 100% increase from the 1970 figures of 3,330 and 13,303 respectively. -3- The percentage of the total housing stock that is multiple family or attached dwelling units has also increased dramatically. The 1970 Census recorded no multiple family or attached units in Diamond Bar, but 3,330 single family dwelling units. In late 1972, 12 attached units were added to the housing supply which totalled some 3,612 units. By 1975 there were 817 multiple or attached units within the 5,339 dwelling unit total. The April 1, 1979 "Quarterly Bulletin" estimated 871 multiple units and 6,417 total dwelling units. This represents an increase from 0% of the total dwelling units in 1970 to over 13% in mid-1979. We estimate that as of 1981 16%, or 1,698 of the 10,011 total dwelling units consisted of attached or multiple units. By the year 2000, this figure is projected at approximately 3,900 multiple units, representing 25% of the total housing supply. If all vacant areas were developed to the maximum densities permitted by the Plan, Diamond Bar would experience the addition of approximately 6,750 dwelling units and a population growth of 22,000 people. However, based upon pending projects, it is not expected that the actual development will reach this theoretical maximum. Rather, it is projected that development in the year 2000 will add approximately 5,550 dwelling units and 18,250 people. aC GOALS The Community General Plan goals establish a common purpose for all the .elements of the plan and also serve as a guide to the agencies responsible for plan implementation. 1. Maintain the rural setting of the community through the retention and maintenance of extensive amounts of natural open space and hillside vegetation. 2. Maintain the predominately detached single family bedroom character of the community. 3. Minimize alteration of the natural terrain. 4. Develop and maintain an efficient and safe regional system of highways to serve the community. 5. Improve traffic circulation and parking in commercial areas. 6. Beautify highways through the use of landscaped parkways. 7. Maintain a safe and efficient system of local streets that is consistent with the rural appearance and community identity. 8. Promote viable commercial activity through neighborhood and local shopping center and minimize the development of strip commercial, especially along the arterial highways, such as Diamond Bar Boulevard. 9. Expand recreational facilities including, but not limited to, parks and teenage recreation centers. LAND USE The major land use issues are related to growth. The need for housing throughout the region must be balanced with environmental concerns and the need for open space preservation. Increasing construction and land costs indicate that a large share of new housing will be in townhouses, condominiums., or apartments. Such developments are seen by the residents as a threat to the rural community character. The Land Use Element attempts to reconcile this apparent conflict. This element consists of the Land Use Map showing the location and intensity of uses which will be allowed and a series of written policies giving specific guidelines to govern future development. The Planning Advisory Committee debated the wisdom of including minimum lot size requirements in the various density classifications. In an effort to encourage innovative and better subdivision design, variety of housing types, and lowered development costs, it was decided that minimum lot size requirements would not be specified. However a minimum 4,000 square foot pad area, exclusive of front yard setbacks, is required in U1 areas. Pad is defined by Los Angeles County Ordinance 21.08.130 as "a building site prepared by artificial means including grading, excavation, filling, or any combination thereof". Land Use Policies 1. Prohibit residential uses in industrial areas, except for caretaker facilities ancillary to an industrial use. Residential uses in commercial areas are allowed only when ancillary to the primary commercial uses. 2. Establish a minimum 4,000 square foot pad area, exclusive of front yard setbacks, in undeveloped U1 areas. 3. Require minimum one acre lot sizes in non -urban areas immediately adjacent to existing one acre development. 4. Restrict multiple family or attached housing to the U3, U4, and U5 categories. 5. Prohibit mobilehome parks in non -urban and industrial areas. 6. Design multiple family developments to minimize their impacts on surrounding neighborhoods and adjacent dwellings. The design shall adhere to the following guidelines: a. Maintain setbacks which are adequate to preserve the privacy of adjacent residences and yards. b. Provide a minimum of 15 feet of landscaping along street frontages. This shall include specimen trees and screening plants or berms. -5- 6. (cont'd.) c. Screen parking and trash areas with landscaping, berms, compatible structures, or a combination of these. d. Locate trash areas so as not to be detrimental to adjacent residential areas. e. Locate driveways so as to minimize impacts on local street traffic. f. Provide sufficient off-street guest parking. 7. Design new subdivisions to minimize their impacts on community character, surrounding neighborhoods, and natural features. Adhere to the following guidelines where possible: a. Minimize alteration of natural hillsides, drainage courses, and vegetation. In particular, preserve significant tree clusters, especially sycamore, alder, eucalyptus, pepper, pine, walnut, and oak trees. b. Preserve major ridgeline form in the existing state. c. Minimize adverse visual impacts on neighboring residential uses. d. Maintain the existing or natural topographic transition between developments. High banks shall not be created adjacent to existing developments. e. Maintain a distance of at least ten feet between structures. Stagger front setbacks so long as there is adequate space for driveway parking in order that vehicles do not obstruct the street. f. Minimize grading of the site and maximize retention of natural topography as follows: (1) Utilize contour grading and landscaping to present a more natural appearance. (2) Minimize grading for roads, streets, and storm drains consistent with public health and safety considerations. Consider reducing road widths to the minimum required for safety. g. Protect the visual quality of highly scenic areas. h. Apply innovative approaches to house placement and design. -7 - i. In non -urban areas, sidewalks, street lights, curbs and gutters may be waived. j. Trees, plants, and ground cover should be selected which will effectively screen or soften the visual impact of new development. All cut and fill slopes shall be planted with adequate plant materials to protect against erosion and fire. k. Provide underground utilities and the unobtrusive placement of utility boxes. 8..Require the beautification of new commercial areas and encourage beautification of existing commercial areas. This can be achieved through the combined efforts of the public and private sectors. Where practical, adhere to the following guidelines: a. Complete landscaping of public rights -of -way. b. Provide a minimum of ten feet of landscaping along the street frontage of commercial uses. This shall include plants, landscaped berms, or a combination of these capable of providing screening up to a height of 42". c. Landscape a minimum of five percent of the parking area. d. Prohibit freestanding portable signs. e. Limit free standing signs to one for each street frontage of a shopping center listing all businesses. The sign should reflect the architectural style of the center. f. All businesses in a center should present a general uniformity of facades. g. Encourage strict adherence to County sign ordinances. 9. Restrict on -street parking by semi -trucks and trailers, especially in or near residential areas. 10. Obtain Regional Planning Commission approval before disturbing any major stands of vegetation as shown on the Conservation and Recreation Hap. 11. Require an adequate clear zone or buffer zone of fire retardant vege- tation on sites where development abuts a high brush fire hazard area. 12. Encourage a variety of development concepts, including the clustering of single family dwelling units, to minimize the costs of public services and utilities. MC 13. Encourage new residential development designs that utilize solar •1 energy use principles including but not limited to the following: - preserve solar rights for individual lots; - locate dwelling sites strategically to minimize space heating and cooling requirements, - maximize southern exposure and solar gain for individual lots; - orient subdivision streets so that they run in a generally east -west direction; - utilize bodies of water such as ponds or artificial lakes to cool nearby downwind structures; - encourage the retrofitting of existing dwelling units for passive and active solar systems; - utilize landscaping and vegetation to inhibit solar exposure in summer months while not interfering with solar gain in winter months (i.e. deciduous trees near driveways and paved areas). Land Jse Policy Clap The land use policy map establishes nine land use classifications for Diamond Bar. Included are two non -urban classifications (Non -Urban and Open Space) and five urban residential classifications (Ul, U2, U3, U4, and U5). All urban classifications may include such services and facilities as schools, utility stations and churches, and non-profit recreation uses, subject to necessary permit procedures. The lot size ranges are typical for the respective classifications. Smaller lot sizes are permitted so long as the development does not exceed the gross density permitted. Within the range of entitlements established by residential land use classifications, transfer of density within a project site is generally encouraged as a means of reducing potential adverse impacts, preserving scenic areas and providing increased open space and design amenities. NON -URBAN - 1.0 or less dwelling units per gross acre - 1.00 to 5 acre lot sizes - 1 acre minimum lot size when adjacent to existing 1 acre developed lots. - Very low density residential - Rural or agricultural - Single family detached dwellings U1 URBAN 1 - 1.1 to 3.2 dwelling units per gross acre - 10,000 to 39,999 square foot lot sizes - Urban very low density (hillside residential) - Large lot residential - Single family detached dwellings -9 - U2 URBAN 2 - 3.3 to 6.0 dwelling units per gross acre - 5,500 to 9,999 square foot lot sizes - Urban low density residential - Single family detached dwellings U3 URBAN 3 - 6.1 to 12.0 dwelling units per gross acre - Urban low/medium density residential - Small lot single family residences, duplexes, triplexes, townhouses, and condominiums U4 URBAN 4 - 12.1 to 22.0 dwelling units per gross acre - Urban medium density residential townhouses, condominiums, and apartments. U 5 URBAN 5 - 22.1 to 35.0 dwelling units per gross acre - Urban high density residential condominiums and apartments. COMMERC IAL : - Retail commercial, service, and office uses I14DUSTRIAL: - Manufacturing, warehousing, and heavy commercial uses - Conditional Use Permit Required OPE14 SPACE: - Recreation, with no more than 10% of the site devoted to structures, parking, and other facilities (This requirement is waived on local park sites of 20 acres or less). - Hiking and equestrian trails - Agriculture - Scientific study - Utility easements - Mineral extraction, including oil production - Subject to the policies of the Conservation and Open Space Element of the County General Plan. DIAMOND BA COMMUNITY PROPOSED LAND USE ?f-i�*�"R�7� .'�'' ..Si� Nonurban 1.0 or Less ......•.... Ut 1.1 - 3.2 U2 3.3 - 6.0 U3 6.1 - 12.0 IIIIIIIIIIIIII�I�II U4 17 1 — ,17 n Commercial "\\ Industrial Open Space -10- Parks Limited SecondaryHwy. v®®®c Secondary Hwy. Significant Ecological Area ram.»..— rr, �� CIRCULATION The circulation element determines the general location and extent of major arterial routes to accommodate the safe and efficient flow of traffic. Diamond Bar is presently served by the Pomona Freeway, the Orange Freeway, and eight County Highways•. The County Plan of Highways proposes the extension and completion of five of these routes. The primary transportation issues in the community revolve around the necessity to balance the impacts on traffic from the expected growth with the residents' desires to maintain a rural atmosphere. Concurrently, the residents are concerned with the limited access of Diamond Bar to surrounding areas. This lack of access is due in part to the large areas of undeveloped land to the north, east, and south. As these areas develop, access to surrounding regions will increase while, simultaneously, pressure on the rural atmosphere will also increase. The paramount circulation issue in the community is the proposed extension of Grand Avenue easterly to the San Bernardino County boundary and westerly to the City of Industry. This route transects Diamond Bar in an east -west direction. Presently, it does not extend beyond Diamond Bar either to the west or east; however, major developments are proposed in both directions and as these projects are completed, Grand Avenue will be extended. Immediately across the San Bernardino County boundary a major new community is proposed for the Chino Hills area. This development encompasses 26 square miles and at project completion could add approximtely 41,000 dwelling units supporting an estimated population of 109,000. At full development the Chino Hills project in combination with projects in Diamond Bar will increase the average daily traffic volume on Grand Avenue, east of Diamond Bar Boulevard, from the present estimate of 4,000 vehicles to 38,800 vehicles. The Chino Hills project represents 23,700 of the projected vehicle increase (or 61%), while completion of projects within Diamond Bar will add approximately 10,000 vehicles daily to the present level. Further, rapid growth in the area may be causing traffic to exceed the current figures shown above for Grand Avenue. As an example, a recently performed private study by the Diamond Bar Country Estates estimates the present traffic on Grand Avenue, east of Diamond Bar Boulevard, to be in excess of 6,000 A.D.T. Grand Avenue, east of Diamond Bar Boulevard, will be increased from two to four lanes and will have the right-of-way necessary to expand to six lanes should traffic volumes warrant such a move. Nevertheless, the increased volume will result in a decrease in the service level at the intersection of Grand Avenue and Diamond Bar Boulevard from Service Level "A" to Service Level "D" as defined by the National Academy of Science -National Research Council's "Highway Capacity Pianual-1965." Level of service is a qualitative measure of the effect of a number of factors, which include speed and travel time, traffic interruptions, freedom to maneuver, safety, driving comfort and convenience, and operating costs. With regard to traffic signal controlled in-ersections, Table I on page 14 describes the various levels of service and intersection capacity utilization. -12- -13- The aforementioned highway improvements will have growth inducing impacts in previously inaccessible areas and may have a detrimental impact on both public health and safety and the natural environment. In order to limit some of these impacts, this Plan suggests the improvement of the impacted inter- sections, the redesignation of certain routes to lesser categories, and carefully controlled development patterns designed to preserve significant areas of open space. Prior to the expansion of Grand Avenue in the Diamond Bar area to 6 lanes, if necessary to maintain intersection capacity utilization of 0.85, Tonner Canyon Road will be connected as a secondary highway with 80 feet of right-of-way from Phillips Ranch Road in the north to the 57 freeway at the Tonner Canyon Connector ramp in the south. Immediately west of the community plan area is an undeveloped area of approximately 600 acres which is bisected by the westerly extension of Grand Avenue. There are 2,547 dwelling units proposed for this area. Without mitigation, the impacts of these developments would reduce service levels on Grand Avenue at the Pomona Freeway and Diamond Bar Boulevard at Sunset Crossing to "E", and Diamond Bar Boulevard at the Pomona Freeway eastbound ramp to "D". Because of the serious impacts on Diamond Bar highways generated by projects occurring outside the community, the plan includes references to service levels and intersection capacity utilization in Circulation Policy 6. Caution should be exercised in reviewing individual projects in the greater Diamond Bar region to insure that the cumulative impacts do not exceed this standard. The development of the northeast portion of Diamond Bar, south of the Pomona Freeway, will result in an additional 1980 dwelling units. The traffic generated from these units will impact efficient flow both in route and at intersections. Average daily traffic volumes are expected to increase significantly on Grand Avenue, Diamond Bar Boulevard, Golden Springs Road and Carpio Drive. In order to reduce the aforementioned impact, the Plan suggests the installation of highway improvements as needed to maintain service level "C". In order to preserve the highly scenic Brea -Canyon Cut -Off area the plan designates Brea Canyon Cut -Off as a limited secondary highway. This is a new classification designed to protect routes in rural areas. The standard improvement for limited secondary routes shall be two traffic lanes on 64 feet of right-of-way. Typically, such improvements would consist of 26-30 feet of pavement with graded shoulders. Left -turn pockets and passing lanes may be provided when required for traffic safety. The right-of-way may be increased up to 80 feet for additional improvements where traffic or drainage conditions so warrant. TABLE I LEVEL OF SERVICE DESCRIPTIONS Level of Traffic Quality Service Nominal Range . of ICU* A Low volumes; high speeds; speed not restricted 0.00 - 0.60 by other vehicles; all signal cycles clear with no vehicles waiting through more than one signal cycle. B Operating speeds beginning to be affected by 0.60 - 0.70 other traffic; between one and ten percent of the signal cycles have one or more vehicles which wait through more than one signal cycle during peak traffic periods. C Operating speeds and maneuverability closely 0.70 - 0.80 controlled by other traffic; between 11 and 30 percent of the signal cycles have one or more vehicles which wait through more than one signal cycle during peak traffic periods; recommended ideal design standard. D Tolerable operating speeds; 31 to 70 percent of 0.80 - 0.90 the signal cycles have one or more vehicles which wait through more than one signal cycle during peak traffic periods; often used as design standard in urban areas. E Capacity; the maximum traffic volume an inter- 0.90 - 1.00 section can accommodate; restricted speeds; 71 to 100 percent of the signal cycles have one or more vehicles which wait through more than one signal cycle during peak traffic periods. F Long queues of traffic; unstable flow; stoppages Not Meaningful of long duration; traffic volume and traffic speed can drop to zero; traffic volume will be less than the volume which occurs at Level of Service E. * ICU (Intersection Capacity Utilization) at various levels of service versus level of service E for urban arterial streets. Source: Highway Capacity Manual, Highway Research Board Special Report 87, National Academy of Sciences, Washington D.C., 1965, page 320. - 14 - -15- A uniform highway setback shall be established 40 feet from the center- line of all limited secondary highways in order to preserve proper sight distances and to help maintain a rural appearance adjacent to the roadway. This setback shall be in addition to any yard requirements contained in the Zoning Ordinance. CIRCULATION POLICIES 1. Improve and maintain the following as major highways with rights -of -way of 100 feet: A. Diamond Bar Boulevard B. Grand Avenue C. Temple Avenue D. Pathfinder Road, between Diamond Bar Boulevard and the 57 Freeway 2. Improve and maintain the following as secondary highways with rights -of -way of 80 feet: A. Golden Springs Drive B. Brea Canyon Road C. Sunset Crossing, westerly of Diamond Bar Boulevard D. Pathfinder Road, westerly of the 57 freeway 3. Designate Brea Canyon Cutoff, westerly of the 57 Freeway, as a limited secondary highway utilizing the existing alignment as much as possible. 4. Protect an 80 foot right-of-way for limited secondary highways. Although initial roadway development shall not exceed a 64 foot right-of-way, building setbacks shall be measured from an 80 foot right-of-way line. 5. Widen Pathfinder Road between its easterly and westerly intersections with Brea Canyon Road to include 2 additional lanes on the 57 Freeway overpass. 6a. Attempt to maintain Service Level "C", as described on Table I on page 14, for all highways in Diamond Bar. 6b. Require projects which would cause Intersection Capacity Utilization to exceed 0.85 (see Table I on page 14) to provide appropriate mitigation measures. At the discretion of the County, these measures may involve actual improvements, such as street widening, or monetary contributions representing a proportionate share of the cost of the improvements. 1 6: (cont'd) 6c. Include as mitigation measures such improvements as: ® Provision of a signal at the intersection of Diamond Bar Boulevard and Tin Drive. ® Widening of Diamond Bar Boulevard, north and south of Golden Springs Drive. ® Modification of the signalization and reconstruction of the median at the intersection of Diamond Bar Boulevard and Golden Springs Drive. 7. Require new residential developments to provide adequate access, traffic controls, sidewalks, and improvements as warranted by an analysis which considers the cumulative impact of surrounding existing and proposed developments. 8. Coordinate with the Counties of San Bernardino and Orange and the Cities of Brea, Pomona, and Industry in the development of interjurisdictional local and arterial routes, bike lanes, and pedestrian/equestrian trails. 9. Encourage the public transportation systems to improve access at a reasonable cost to the major shopping/activity centers, such as the Brea and Puente Shopping Malls. 10. Promote the development of bikelanes along all arterial routes in Diamond Bar. 11. Require all new commercial developments to provide for safe and efficient parking, internal traffic flow, ingress, and egress. 12. Encourage existing commercial centers, where possible, to provide improved parking designs to facilitate ingress, egress, and interior circulation. 13. Landscape arterial routes in Diamond Bar to improve and promote the appearance of a rural atmosphere. 14. Design local street systems in new residential developments to minimize high volumes of through traffic. 15. To the extent that the Municipal Advisory Council establishes parking standards that are more stringent than the County's, those standards will apply in Diamond Bar. TABLE II DIAMOND BAR HIGHWAY PLANS 1980 COUNTYWIDE PROPOSED HIGHWAY GENERAL PLAN DIAMOND BAR Existing Routes Pomona Freeway (Route 60) Freeway Freeway Orange Freeway (Route 57) Freeway Freeway Diamond Bar Boulevard Major Major Grand Avenue Major Major Pathfinder Road Major Major (East of the 57 Fwy. ) Brea Canyon Cut -Off Limited Limited Secondary Secondary Golden Springs Drive Secondary Secondary Sunset Crossing Secondary Secondary Pathfinder Road Secondary Secondary (West of the 57 Fwy . ) Brea Canyon Road Secondary Secondary Proposed Routes Temple Avenue Major Major Grand Avenue Major Major (East of Shotgun Lane) Pathfinder Road Secondary Secondary (West of the 57 Fwy. ) Golden Springs Drive Secondary Secondary (North of Sunset Crossing) Sunset Crossing Secondary Secondary (West of Prospectors Rd.) -17- NOISE The Noise Element provides a basic strategy for the control and abatement of noise. It provides quantitative data identifying noise levels, delineates areas with acceptable noise environments, and provides standards which will protect those areas. Noise Environment Vehicle traffic is the only critical noise source in Diamond Bar. The areas experiencing the highest noise levels are the corridors adjacent to the major traffic arteries® the Pomona Freeway, the Orange Freeway, Diamond Bar Boulevard, Golden Springs Road, and Grand Avenue. Three additional roadways that generate moderate noise levels are Sunset Crossing, Pathfinder Road, and Brea Canyon Road. The community is skirted on its northern edge by heavily traveled Union Pacific Railroad tracks serving the City of Industry. "Level day night" (Ldn) noise contours have been calculated adjacent to these roadways using analytical noise exposure modeling techniques which yield noise exposure levels in typical situations. Adjustments were made for street width and for grade. These predictive techniques are accurate to 3+ dB and decrease with increasing distance from the source. Therefore, the contours generated are not absolute lines of demarcation but general indications of bands of similar noise exposures. The map on page 18 shows the areas which, based on the Ldn calculation, can be assumed to be experiencing noise levels in excess of 60 dBA. Large scale maps showing noise contours in 5 dB increments down to.60 dBA may be viewed in the offices of the Department of Regional Planning, 320 West Temple Street, Los Angeles, California 90012. Noise Sensitive Features State law requires evaluation of the noise environments of the following noise sensitive facilities: schools, hospitals, rest homes, long term medical or mental health care facilities, or any other use deemed noise sensitive by local jurisdictions. While there are no medical facilities in the community, there are seven schools which should be monitored. The community determined that libraries and day care centers are noise sensitive. There are two county libraries within the community. Inasmuch as no agency currently has the financial capability to monitor these sites, exterior noise levels can only be assumed from the noise contours calculated using the Ldn methodology. The schools and both libraries are situated partially or wholly within the 60 dBA contour. -18- a DIAMOND BAR COMMUNITY STUDY AREA CURRENT NOISE EXPOSURE 1 i 1 1 13 a � 1 1 L , poMONA FNW►' 'vY O AVE. , 1 f 1 � 1 � 1 � � • r-------+ 6,flF v 11,06 1 ARE AS EX►ERIENCING ,4 �OVER 60tl6ALen 1 D SCHOOLS r ow �..�—mmM NJ - 19 - TABLE III RANGE OF TYPICAL OUTDDOR NOISE ENVIRONMENTS EXPRESSED IN TERMS OF DAY NIGHT SOUND LEVEL (L n)e dB DAY -NIGHT SOUND LEVEL DECIBELS QUALITATIVE DESCRIPTIONS City Noise (Downtown Major ® 80 Metropolis) Very Noisy ® 70 — Noisy Urban Urban Z u, Nsu Suburban Small Town & Ouiet Suburban — 20 — OUTDOOR LOCATIONS Los Angeles • 3rd Floor Apartment Next To Freeway Los Angeles • Mile From Touch Down At Major Airport Los Angeles • Downtown With Some Construction Activity Diamond Bar - Corner of Diamond Bar Blvd. & Grand Ave. Watts • B Miles From Touch Down At Major Airport Newport . 3.5 Miles From Takeoff At Small Airport Rowland Heights • Reedview Dr. & Brea Canyon Cut-off San Diego • Wooded Residential California • Tomato Field On Farm -21- Noise Exposure Inventory The table on page 23 shows the number of dwelling units exposed to various levels of noise in excess of 60 dBA. Because the contours indicate only approximate bands of noise exposure there are ranges of exposure shown for each decibel band. Projected residential development will cause an increase in average daily traffic (A.D.T.) on existing routes. This coupled with the extension of Grand Avenue both to the east and west, and the extension of Sunset Crossing to the southwest to intersect Grand Avenue, will impact noise levels and noise exposure in the community. The table and map on pages 23 and 24 show projected noise corridors and noise exposure. Noise Policies 1. Insulate all new residences and noise sensitive facilities* in areas of 60+ dBA or more so that interior noise levels do not exceed 45 dBA. This may be accomplished through the use of walls, earth berms, landscaping, special setbacks, or a combination of these in order to mitigate noise problems and to reduce overall community noise exposure. 2. Encourage noise sensitive facilities to locate in areas experiencing noise levels of 65 dBA or less (as measured or calculated on the Ldn scale). 3. Designate all those areas shown on the General Plan map that are within a projected annual contour of 60 dBA as "Noise Impact Management Areas". This classification will be overlaid onto other land use classifications; i.e., property designated "residential" will be redesignated °'residential -noise impact management area". 4. Review any development proposals within "noise impact management areas" for design concepts to assure consistency with the policies embodied in the community general plan noise element. 5. As changes occur in the factors which contribute to "noise exposure levels", revised noise contours will be prepared. Reduction or expansion of the extent of the annual Ldn contours of 60 and/or greater dBA will be accompanied by appropriate changes in the "Noise Impact Management Area" classifications on the General Plan map. * Noise sensitive facilities include the following: schools, hospitals, rest homes, long term medical or mental health care facilities, libraries, and day care centers. ®23® 6. Encourage increased enforcement of existing regulations. 7. Encourage remedial corrective measures to reduce noise levels in existing residential areas exposed to Ldn's of 65 dBA:or more. These measures may include installation of noise attenuation walls and increased landscaping. TABLE IV CURRENT COMMUNITY NOISE EXPOSURE LEVELS* ASSESSORS MAP BOOKS 8278 80-85 dBA 75-79 dBA ----- --- 70-74 10-23 dBA d.u.s 65-69 dBA 30-51 d.u.s 60-64 36-53 dBA d.u.s 8281 ----- 0-16 d.u.s 17-38 d.u.s 61-146 d.u.s 141-262 d.u.s 8284 ----- --- --- 31-48 d.u.s 68-92 d.u.s 8285 ----- --- --- 63-85 d.u.s 136-214 d.u.s 8292 ----- -®- 3-9 d.u.s 48-61 d.u.s 88-154 d.u.s 8293 ----- --- --- 82-92 d.u.s 59-100 d.u.s 8701 ----- --- --- 37-113 d.u.s 26-137 d.u.s 8702 ----- --- --- 48-67 d.u.s 33-57 d.u.s 8703 ----- 0-5 d.u.s 7-37 d.u.s 45-112 d.u.s 125-215 d.u.s 8706 ----- --- --- 39-57 d.u.s 36-111 d.u.s 8717 ----- --- --- 61-109 d.u.s 155-274 d.u.s 8718 ----- 16-42 d.u.s 33-65 d.u.s 59-96 d.u.s 145-206 d.u.s * The figures in each decibel range band indicate the potential number of dwelling units impacted. DIAMOND BAR COMMUNITY STUDY ••**%�k PROJECTED NOISE EXPOSURE / s , ♦, / i pMONA FWy Ir ® US � 0 Q e i {fs1T FR • • 1 Q � • 1 , mnmfr m If le ' ,, ©AREAS ExrER1ENCINC 0"Elk 60 ODA Ler. O SCHOOLS -24- E TABLE V PROJECTED COMMUNITY NOISE EXPOSURE LEVELS* ASSESSOR'S' MAP BOOK 80-85 dBA 75-80 dBA 70-75 dBA 65-70 dBA 60-65 dBA 8278 - 0-16 d.u.s 27-44 d.u.s 92-123 d.u.s 69-120 d.u.s 8281 - 16-53 d.u.s 49-83 d.u.s 156-210 d.u.s 264-352 d.u.s 8284 - - 27-34 d.u.s 53-96 d.u.s 63-101 d.u.s 8285 - - 25-36 d.u.s 122-170 d.u.s 131-241 d.u.s 8292 - 0-12 d.u.s 15-25 d.u.s 155-189 d.u.s 114-165 d.u.s 8293 - - 0-5 d.u.s 94-107 d.u.s 147-177 d.u.s 8701 - - 5-20 d.u.s 60-125 d.u.s 110-140 d.u.s 8702 - - 3-21 d.u.s 237-270 d.u.s 206-216 d.u.s 8703 - 10-25 d.u.s 49-75 d.u.s 127-158 d.u.s 214-251 d.u.s 8706 - 11-25 d.u.s 27-57 d.u.s 399-457 d.u.s 349-468 d.u.s 8717 - 12-51 d.u.s 173-257 d.u.s 397-551 d.u.s 8718 23-48 d.u.s 42-75 d.u.s 115-135 d.u.s 133-175 d.u.s 277-283 d.u.s 8769 0-75 d.u.s * The figures in each decibel range indicate the potential number of units impacted. -25- OUTDOOR RECREATION Recreation is an integral and essential part of the Diamond Bar lifestyle. The primary purpose of this element is to expand recreational facilities including, but not limited to, parks and teenage recreation centers. The County advocates that local parks be developed to provide at least four acres of parks for every 1,000 persons within a service radius of a quarter to a half mile, or easy walking distance for youngsters and senior citizens. Based on this requirement, Diamond Bar is presently deficient approximately 74 acres of local parkland. If the area develops to capacity the deficiency will increase to 147 acres. Los Angeles County now has three park sites in Diamond Bar® a developed facility, a partially developed site, and a site under construction: 1. Sycamore Canyon Park contains 50 acres of which six acres are developed with picnic areas, a multipurpose ball diamond, and a community building while the remaining 44 acres consist of undeveloped hillsides. 2. Heritage Park is a three acre site developed with playfields, basketball courts, and a recreation building. 3. Maple Hill Park is a five acre site under construction. Certain heavily populated portions of the community are not served by these sites and lack parks. Local parks should ideally be situated to avoid the crossing of major vehicular arterials by pedestrian users. Local park acreage needs consequently have been based on the population residing within areas enclosed by major traffic arterials. Eight such areas exist in Diamond Bar and are shown on the map on page 29. Table V on page 27 shows the existing and projected population and park acreage needs for these areas. —26— Existing Area Dwelling Units 1 1,099 2 920 3 1,436 4 1,431 5 1,917 6 2,343 7 600 8 287 TOTALS 109033 TABLE VI Existine Park Needs Existing Existing Population Park Needs 3,616 14.5 3,027 12.1 4,724 18.9 4,708 18.8 6,307 25.2 7,708 30.8 1,974 7.9 944 3.8 33,008 132.0 Projected Park Needs* Existing Park Site 50 5 3 58 Additional Park Acreage Required 14.5 12.1 31.1 (credit) 18.8 25.2 25.8 4.9 74.0 (Based upon 5,550 additional units & 18,247 additional people) Projected Additional Projected Projected Projected Existing Park Acreage Area Dwelling Units Population Park Needs Park Site Required 1 2,119 6,972 27.9 -- 27.9 2 920 3,027 12.1 12.1 3 1,655 5,445 21.8 50 28.2 (credit) 4 3,4ll 11,222 44.9 44.9 5 2,956 9,725 38.9 -- 38.9 6 2,906 9,561 38.2 5 33.2 7 600 1,974 7.9 3 4.9 8 1,012 31329 13.3 -- 13.3 TOTALS 159579 51,255 205.0 58 147.0 *Because the Country provides a private recreation center for its homeowners, it has not been included in these charts. -27- CM-M To help rectify these deficiencies, the County has adopted a Park Dedication Ordinance (Quimby Ordinance) requiring that the subdivider of a new residential subdivision provide local park space to serve the subdivision. A specific formula establishes the acreage required based on the size of the subdivision and its potential density. The subdivider may also meet this obligation by paying a fee in lieu of some or all of the required acreage. The County determines how the obligation is met. Recreation Policies 1.. Require that all new subdivisions having a Quimby Act requirement of at least five acres dedicate land for local parks. 2. Where the Quimby Act requirement is at least five acres of local park land, the subdivider may be allowed, with the approval of the M.A.C., to install recreation facilities and improvements to reduce the amount of park land required. In such cases the value of the improvements provided must at least equal the value of the land which otherwise would have been required for local parks. 3. Use school sites to supplement recreational services, especially in those areas where parks are not available. 4. Encourage local organizations to develop, maintain, and operate recreational facilities on undeveloped public land. 5. Develop a system of bikeways along major and secondary highways. 6. Develop a system of accessible equestrian and hiking trails which will tie into the Regional Trail System. . Pi I DIAMOND BAR COMMUNITY CiDRSE IRVATION AND RECREATION pmoct Fork • co oikvwv� Arm SOL" ry — — — — — 4bo- MAP* wim tio Np 6 %P4 I cl 9 2 3 4 Cou k — 29 5 W WW� W W PLAN IMPLEMENTATION ® Adoption of the Diamond Bar Community General Plan does not mark the end of the planning process, but rather signals the beginning of activities designed to bring into reality the policies set forth in both the Community Plan Element and the Countywide Elements. The Community Plan and Countywide Elements are decision making tools which will guide public and private investment in the community. Proposals by public agencies to acquire or dispose of land or undertake construction projects in the community will be reviewed for consistency with the plans. The County will initiate necessary changes in police power regulations, especially with respect to zoning ordinances, to help assure that private development also conforms to the goals and policies of the plan. Although the police power provides a valuable tool in plan implementation, it is limited because it is mainly regulatory in nature. Effectuation of many plan proposals, such as acquisition and development of local parks and establishment of a trail system, will require action programs to be undertaken by various public agencies or formation of special districts. Such programs will depend heavily upon enthusiastic community support. This support demands that the plan be readily available to and understood by the residents and property owners of Diamond Bar. In order to facilitate community involvement in planning activities, the plan recommends the formation of a Diamond Bar Zoned District. The community is now part of the larger San Jose Zoned District, which sometimes causes confusion regarding public notice of zoning and subdivision cases. Just as the adoption of the plan does not end the planning process, the plan itself must be periodically reviewed to assure that it continues to address the needs of the community. Any amendment will be reviewed by the Planning Advisory Committee and other interested community groups. In addition at least one advertised community - wide meeting will be held in Diamond Bar during evening hours to discuss the proposed amendment. Finally, no amendment shall become effective until it is subjected to public hearings and approval of the Regional Planning Commission and Board of Supervisors. The community is encouraged to review and discuss all proposed develop- ment projects with the Department of Regional Planning, the Diamond Bar Municipal Advisory Council, and other appropriate agencies. The Planning Advisory Committee has moved to continue the development of the Community Plan through discussion with contiguous, unincorporated areas to refine the plan by defining Diamond Bar's sphere of influence. -30-