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HomeMy WebLinkAboutCity Council - 2009-49 RESOLUTION NO. 2009-49 A RESOLUTION OF THE CITY COUNCIL OF THE CITE'OF HUNTINGTON BEACH APPROVING GENERAL PLAN AMENDMENT NO. 08-0I0 WHEREAS, General Plan Amendment No. 08-010 proposes to amend the Environmental Hazards Element by incorporating language referencing the adopted Local Hazards Mitigation Plan pursuant to Exhibit"A" attached hereto; and Pursuant to California Government Code,the Planning Commission of the City of Huntington Beach, after notice duly given, held a public hearing to consider General Plan Amendment No. 08-010 and recommended approval of said entitlement to the City Council; and Pursuant to California Government Code, the City Council of the City of Huntington Beach, after notice duly given, held a public hearing to consider General Plan Amendment No. 08-010; and The City Council finds that said General Plan Amendment No. 08-010 is necessary for the changing needs and orderly development of the community, is necessary to accomplish refinement of the General Plan, and is consistent with other elements of the General Plan. NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Huntington Beach as follows: SECTION 1: The City Council of the City of Huntington Beach hereby adopts said Amendment to the General Plan. SECTION 2: That General Plan Amendment No. 08-010, which amends the General Plan Environmental Hazards Element by incorporating reference language identifying the adopted Local Hazards Mitigation Plan, attached hereto as Exhibit A, is hereby approved. The director of Planning is hereby directed to prepare and file an amended Environmental Hazards Element. A copy of said element, as amended, shall be available for inspection at the Planning Department. 09-213 8/35714 1 Resolution No. 2009-49 PASSED AND ADOPTED by the City Council of the City of Huntington Beach at a regular meeting thereof held on the 8th day of September , 2009. 0 MY'or ATTEST: City Clerk APPROVED AS TO FORM: 4:Cit�Attormey k 4 3010� REVIEW A D APPROVED: INITIATED AND APPROVED: ,,, 4444rj�- y dministrator Plann ng D rector 09-2138/35714 2 Exhibit"A"- Resolution No.200949 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT STATUTORY QUI MENTS Government Code Section 65302(g)states the following: "The General Plan shall include a safety element for the protection of the community from any unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure, tsunami. seiche, and dam failure; slope stability leading to mudslides and landslides;subsidence and other geologic hazards known to the legislative body;flooding;and wild land and urban fires." This Element addresses flooding as it pertains to geologic, seismic and soils hazards. This Environmental Hazards Element and the referenced materials together satisfy the geologic and seismic portion of the Section 65302(g)requirement. TECHNICAL SYNOPSIS This Element of the General Plan is the first step in a comprehensive update to be completed for the geologid and seismic safety issues. This Element, when used in conjunction with Appendix A, the 1974 City of Huntington Beach Seismic Safety Element (the operative document on file with the California Department of Conservation Division of Mines and Geology), and the referenced materials, serves as an adequate basis for a geologic and seismic safety review. A regional perspective is provided to establish the geologic/seismic context for the City. Figures EH-I through EH-I1 are used to summarize the types and level of geologic/seismic hazards present in the City. Most of the geologic and seismic hazards that have the potential to impact the City are due to the active Newport-Inglewood fault, the shallow water table, and the relatively loose nature of recent sedimentary deposits. Individually, or in combination, these factors may generate surface fault rupture, severe ground shaking,subsidence,methane,and other relatively minor hazards. Each of these hazards has been identified and described in the following sections: Surface Geology, Liquefaction, Tsunami and Seiche, Subsidence, Methane, Flooding, and Other Minor Geologic and Soil Engineering Hazards. A local Hazards Mitigation Plan has been prepared in conjunction with adjacent jurisdictions and local school districts to mitigate risks from natural disasters and is referenced in this element. A. SURFACE GEOLOGY The City of Huntington Beach lies on a coastal plain above recently deposited sediment. The sediment is deposited on top of older bedrock formations buried thousands of feet below the surface. These recent sedimentary deposits originally accumulated in beach, river, bay, and estuary environments at or near sea level. However, due to ongoing seismic uplift and folding, these deposits now form mesas at higher elevations. Subsequent erosion from wave action has produced coastal bluffs exposing these deposits. THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-I Exhibit"A"-Resolution No.2009-49 Q tJ W N W W SEAL " WESTMINSTER BEACH B" o m Y z MC z FADDEN z EDINGER QYa2 HEIL WARNER FOUNTAIN VALLEY .4 • 405 •♦ TER ♦• '�YD/AGO ,♦OUNTY OFORANGE QYa2 fP l T (BOLSA CHICA N .♦ GARFIELD PACIFIC OCEAN YORKTOWN ADAMS INDIANAPOLIS R ATLANTA HAMILTON QYa2 LEGEND eANNING COSTA City Boundary MESA (Qya�Tidal Flat Alluvium (Qya)Younger Alluvial Material (Qoa)Older Alluvial Material SOURCE:Tinsley,J.C.,and others,1985,USGS Professional Paper 1360.Figure 146 SURFACE GEOLOGY CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-2 Exhibit"A" - Resolution No.2009-49 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT The sedimentary deposits found in Huntington Beach consist of Quaternary deposits (Pleistocene' and Holocene) as shown on Figure EH-1. The older Quaternary deposits are exposed on the mesas (Bolsa Chica and Huntington Beach) and in the perimeter bluffs; these are termed older alluvium or terrace materials of the Lakewood and San Pedro Formations? The mesas (topographically high areas) are surrounded and separated by younger alluvium which (from north to south) fills the gaps (topographically low areas) at Seal Beach, Bolsa Chica and the Santa Ana River. Younger alluvium is divided into river floodplain deposits (washed in from the northeast as sand, gravel and silt), and tidal flat/lagoonal type deposits lie in the gaps(finer-grained silts and clays). Peat and organic soils are found within the younger alluvium up to about 25 feet (average 5-10 feet thick)4 These fine-grained deposits are expansive,5 compressible,and generally have fair to poor geotechnical engineering properties. Floodplain sands and silts are largely unconsolidated and contain the peat layers. On the whole, these deposits are subject to liquefaction(fine sand and peat), settlement, expansion, and have good to fair engineering properties,except for peat which have poor to very poor engineering properties 6 The oldest terrace deposits consist of sand with interbeds of silty clay and clay, overlain by interlayered sand-gravel and silt-clay beds. All older alluvium is unconsolidated to semi-consolidated, contains "aquifers" in the thicker sand units, has low-moderate expansive soil qualities, has a moderate to high erosion potential, and is susceptible to landslide/slope instability/erosion(Figure EH-2)at the edge of the bluffs and in canyons. 1. Near Surface Water Depth The City is underlain by shallow near surface water8 which is of interest with regard to liquefaction potential (within depths of 0-50 feet) and as a hazard for construction(within depths of 0-30 feet) (Figure EH-3). This water is found in the alluvial valley and mesa areas as perched water and in shallow aquifers. In the gap areas between the mesas,the City appears to be entirely underlain by water at less than 50 feet deep. These alluvial floodplain(gap)areas have the greatest concentration of shallow water with depths less than 30 feet and most often less than 5 feet deep. The mesa areas(because of their higher elevations)have water depths of 10 feet to greater than 30 feet within the older alluvium. In the northeastern and eastern City areas water depths are 5-30 feet beneath the floodplain deposits. Narrow strips along the immediate coastline have water depths of less than 10 feet. 1 11,000-1,700,000 years before present- 2 0-11,000 years before present. 3 City of Huntington Beach Seismic Safety Element,1974. 4 City of Huntington Beach Geotechnical inputs,1974. 5 City of Huntington Beach Seismic Safety Element,1974. 6 City of Huntington Beach Seismic Safety Element,1974. City of Huntington Beach Seismic Safety Element,1974. 8 Sprouc and others,1980_ THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-3 Exhibit"A"- Resolution No.2009-49 U � ii W �iyl SEAL I " WESTMINSTER BEACH i eorsA mc m FADDEN EDINGER + I :. .�. HEL • "®` WARNER FOUNTAIN I VALLEY v " •®• 405 SLATER •® COUNTY OF •� °TAMT • ORANGE �• (soLSACHICA) •� ELLIS .` GARFIELD ®s L YGMTOWN 0 A ADAMS INDIANAPOLIS _ 1 `a- ATLANTA HAWLTON d BANNING Legend ' COSTA City Boundary r s MESA High Potential for all Coastal Bluffs Low Potential Very Low Potential No Potential X Source: Cm*of OmW,1987,Ora Ve Cou*Hazar&w Waste Manap ent Plan ? ' POTENTIALLY UNSTABLE SLOPE AREAS o as a.o CITY OF.HUNTINGTON BEACH GENERAL PLAN iEH-2 L�J V-EH-4 Exhibit"A"- Resolution No.2009-49 a U w o U d � J ? o r m W rn z SEAL WESTMWSTER BEACH BOLSA 3 0 = U 6 Y ? ~ m a Mc o } .> ODEN 3 G w EDINGEfl HEI L �30 <•. WARNER U AI<�> FO NT N :•jf:: �:oeeas: VALLEY %.... S ATER 5 `r9 ti O� F 00 �T FIT F 9 J Q =- _ - LIS z Y > ¢ Cn U Com 3 GARFIELD S� z YORKTOWN a a 9 2j ADAMS iu t I' I i INDIANAPOUS F U � ATLANTA a HAMILTON Legend nd City Boundary� i n BA NNING a _ >30 Feet COSTA t _1.. 0 30 Feet MESA t - -1 Fe et eet F 3 5 eet < 3 Feet Source: led b Tinstey,J.C. and others t985 USGS Professional Paper i360 F' ure t4T Sou .Comp Y aP g r h� m S offs and others.1390 from p rs. - NEAR SURFACE WATER CITY OF HUNTINGTON BEACH GENERAL PLAN EH-3 V-EH-5 Exhibit"A" -Resolution No.2009-49 SIERRA as.7.9 BASIN ®1a88,M�6.S NEVA®A Owens A ® �\ t.. CENTRAL Valley .; �� arktield VALLEY RAN �'qM"N 1946,10* San Luis .® Plain Obispo ::::: �1952 .,, M T.8 � �G� R =194T M98.5 Fit 6 M®JAY E��\ T R A S P01mdo1e Pt.Conceptlon Santa •:. ANGES 199 ,M®T.3 Barbaro 1994 Ian Pose FLt •tr Mae. f •,;:, AIW 1967,mess 19"06 S. 1948,M-6.0 Santo Cruz Island «`�L lkmv $�4 I937 Salton Sea Catalina qN, = �/ `2r $rawle O Island ��► r 8eletnlc C, Zen 1042 �A Son Oisgo •�.� 48 mm/yr � r` 1�A£X1Co 8.4 SOURCE:Scientists of the USGS and Southern California Earthquake Center,1994, Science,October 21,1994 figure 1 REGIONAL FAULT MAP 0 50Km 100Km.S2 EH-4 Z v City of Huntington Beach General Plan V-EH-6 Exhibit"A"- Resolution No.2009-49 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT 2. Faults a. General All of southern California geology and seismicity is affected by plate tectonics and the forces which cause these plates to move within the earth's crust. Faults are formed at the plate boundaries and within the plates (Figure EH 4). Those which cause the plates to slip horizontally past one another are strike,slip faults while mainly vertical movement is along normal, reverse or thrust faults9. These fault movements cause earthquakes deep in the crust and may cause surface fault rupture or deformation along buried(blind)thrust faults. This seismotectonic setting has been a part of the evolution of the Los Angeles/Orange County landscape for the past 5 million years or so. The most important fault to the City is the Newport-Inglewood. b. Newport-Inglewood Fault Zone The Newport-Inglewood fault zone is an active right-lateral fault system consisting of a series of en echelon10 fault segments and anticlinal folds'1 that are believed to be the expression of a deep-seated fault within the basement rock.12 The fault zone is visible on the surface as a series of northwest-trending elongated hills, including Signal Hill and the Dominguez Hills, extending from Newport Beach to Beverly Hills. The total fault length is about 44 miles. The surface and subsurface segments of the fault in the City are shown on Figure ER-5. The estimated maximum earthquake assigned to the fault zone is magnitude(M) 7, based on its estimated rupture length versus magnitude relationship by Slemmons(1982) and its slip rate. The expected(average) amount of surface fault rupture on any given fault trace for the maximum probable or maximum credible earthquake range from zero to one foot or so for magnitudes under M6.0, and from one foot to ten feet or more for magnitudes between M6.0-7.5. C. Other Fault Segments,Activity Criteria,and Fault Zoning Faults adjacent to, within and beneath the City may be classified as inactive, potentially active, or active. Faults classified as inactive (no demonstrated movement in the past 2 million years) are of no present concern as earthquake sources and are not discussed further. Potentially active faults show evidence of movement and may be possible earthquake sources, but no data are known to conclusively demonstrate Holocene fault movement (within the past 10,000-12,000 years). Active faults are the most concern for earthquake generation and fault rupture potential since they have documented Holocene fault movement or are clearly associated with historic seismicity. Alquist-Priolo Earthquake Fault (formerly Special Studies) Zone Maps delineate active faults and potentially active faults considered by the State to be "sufficiently active"and"well-defined." The City Seismic Safety Element(1974)delineates fault zones of concern in the City; these are fault segments within the Newport-Inglewood fault zone which were deemed active of potentially active at the time the City of Huntington Beach Seismic Safety Element was adopted (1974). The California Division of Mines and Geology(1992)has delineated Alquist-Priolo study zones within the City along the Newport-Inglewood fault zone. 9 A fault with a dip of45 degrees or less with horizontal compression rather vertical displacement. 10 Faults that are in an overlapping or staggered amr gement. 1 I Convex upward folds with cores containing the stratipraphically older rocks. 12 Bryant,1988;Barrows,1974. THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-7 Exhibit"A"-Resolution No.200949 w U � z o SEAL ' WESTMINSTER BEACHBOLSA �oEa • •—••—•—•—• EDINGER f ® — HEIL WARNER FOUNTAIN —•®;�� VALLEY �� `•`` •SLATER 405 •TALBERT "n for ®O ma's `• ®i®�� doh — \. ..� GARFIED 44 ® r• nito n AVenU �; YORKTOWN LEGEND --_ auh City Boundary o , �re`veF AOAMg CategoryA _ ° ® 9r`„ ` wou+NAPous Alqust Prdo Special Studies ®® Category B for a d p ur danttllarrd subsurface specW T @,00� , \ ns ' HAMILTON evaluator of faub fbr al habitable structures BANNING 000°o Category C Special Sfudes,induct' a subsurface any %ation, ® COSTA for affical and important land uses MESA Category D PACE Inacive or nona>astK subsurface investigatim a� mqueed by Ry may be C o ?? Fault Uncertain SOURCE (Sly OtHudingtar Beadr,1974 Seisms Sagely Element,Fon 3.1; T modified usk g Lemon&Associates,1986,Fqm 2 and 3 NEWPORT-INGLEWOOD FAULT ZONE ° °S 10 EH-5 CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-8 Exhibit"A"- Resolution No.200949 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT These zones generally coincide with a portion of the fault zones of concern in the 1974 Seismic Safety Element, specifically the southern segment of the North Branch fault. Upon review of the State Division of Mines and Geology's original determination by Leighton&Associates(1986), faults were suggested to be four categories(Figure EH-5). Extensive fault activity investigation work for the Bolsa Chica Project13 in large part confirmed the opinion of 1986 Leighton&Associates. In addition,the section of the northern segment of the North Branch fault within Bolsa Chica(as shown on the City of Huntington Beach's 1974 Seismic Safety Element fault map)is also considered active, and therefore equivalent to the "A" faults of Leighton & Associates. This investigation also concluded that the South Branch is classed neither active nor potentially active on the Bolsa Chica site, and the Bolsa-Fairview fault segment is pre-Holocene, but considered potentially active lacking specific field data to the contrary. No opinion was made regarding other faults shown on the City's 1974 Seismic Safety Element map. d. Buried(Blind)'Thrusts The aforementioned strike-slip fault types have surface expressions (fault traces) which allow zoning in order to reduce the potential effects of fault rupture on structures. The blind or buried thrusts have been the focus of more study since the 1987 Whittier Narrows magnitude(MI) 5.9 earthquake and the 1994 M=6.7 Northridge earthquake. These faults typically do not offset surface deposits, however do generate co-seismic uplift and movement on fault traces at substantial depth. Table EH-1 lists the following: 1) active or potentially active faults which may affect the City, including segments of the Newport-Inglewood fault zone in the City which are deemed capable of producing fault rupture due to co-seismic or primary seismic activity; and 2)the blind thrusts which are discussed below as earthquake sources. C. Earthquake Ground Shaking Both the strike-slip faults and blind thrusts identified in Table EH-1 have been identified in the region as either having generated or being capable of generating significant earthquakes. The near-City region has experienced several significant earthquakes in historic times which are catalogued by many authors(Figure EI1-6). Large earthquakes in 1769 (name not identified), 1812 (possibly Newport-Inglewood), 1855 (Newport-Inglewood or concealed fault of unknown name),and 1920, 1933,and 1941 (Newport-Inglewood) have been associated with faults located in or near the City. The magnitude 6.3 1933 Long Beach earthquake actually occurred near Huntington Beach/Newport Beach on the Newport-Inglewood fault zone about 3.5 miles into the offshore area. Frequency of Occurrence and Magnitude Based on discussion by Dolan et al. (1994), some rough estimates of earthquake recurrence intervals are: 1) for a magnitude M7.6 over an entire zone of the Elysian, Compton-Los Alamitos, and Palos Verdes faults was 3,300 years, and 2)for the Newport-Inglewood fault zone 200-2,000 years for a M7+event based on a wide range of possible slip rates. The Bolsa Chica EIS/E1R (1992) determined that the slip rate of 0.5 mm/yr was appropriate; this yields a recurrence interval at the high end of the 200-2,000 year range for the M7+event. 13 County of Orange, 1993. THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-9 Exhibit"A"-Resolution No.2009-49 HAZARDS CHAPTER Environmental Hazards Element TABLE EH-1 Active/Potentially Active Faults Which May Affect the City of Huntington Beach ma' FAULTS WITH MAPPED SURFACE TRACES Elsinore[28] No NW-SE 6.75 7.5 0.11-0.189 Newport-Inglewood Yes NW-SE 5.75 7.0 0.55-1.0g [<2] Palos No NW-SE 6.75 7.5 0.34-0.53g Verdes-Coronado Bank[10] Raymond[30] No E-W 4.0 7.5 0.02-0.21g San Andreas[51] No NW-SE 8.0 8.3 0.11-0.14g [long period motions impt.] Sierra Madre-San No E-W 6.0 7.5 0.07-0.20g Fernando[32] Whittier-North No NW-SE 6.0 7.5 0.11-0.30g Elsinore[19] BLIND OR BURIED THRUST FAULTS Elysian Park[25] No E-W,WNW-ESE 5.75 7+ Whittier 5.9 Compton-Los No NW-SE 5-6? 7+ Little known; Alamitos[<10] possible association w/NIFZ Torrance- No NW-SE 5-6? 7+ Little known; Wilmington[<10] apparent association w/PVFZ THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-10 Exhibit"A" -Resolution No.200949 1 CALIFORNIA N EV�DA MONTEREY 1 ARIZ NA �1\ X \\ 4 X X XX LO aANLES,* X X �XX � X L1 X \ ' X ® X X , XX X X X �SAN DIE \ PACIFIC \ OCEAN EXPLANATION OSITE LOCATION (+): M = 8.0 + Latitude — 33.6875 N Q M = 7.0-7.9 Longitude — 118.0000 W Q M = 6.0-6.9 p M = 5.0-5.9 X M = 4.0-4.9 SOURCE:Eavicom,1994,using EQSEARCH by Blake,1994 update REGIONAL EARTHQUAKES a ,� WITHIN 100 MILES OF CITY z LLER City of Huntington Beach General Plan V-EH-1 i Exhibit"A"- Resolution No.2009-49 HAZARDS CHAPTER Environmental Hazards Element Faults in the region are shown on Figure E114; the associated earthquake epicenters (Richter magnitude M> 4.0 within 100 miles) since 1800 are shown on Figure EH-6. Table E11-1 gives the geologic and estimated earthquake parameters associated with each fault within 50 miles (the San Andreas is 51 miles away). From a planning perspective,these are the faults which are most likely to have significant affects on the City during the foreseeable future with regard to producing seismic hazards. Moderate to large earthquakes can occur on previously unmapped and unexpected fault or fold structures possibly yielding much higher ground shaking intensities than previously considered.14 Earthquake epicenter data developed for this study (Figure EH-6), suggest that the 6.5 to 7.0 magnitude event represents a realistic magnitude of earthquake upon which to base structural design for the City. The Uniform Building Code provides standards for a seismic design of structures which have been used to provide the currently acceptable level of protection to most structures and occupants. Intensity and Acceleration The two most consistent(covering the entire City)data bases for assessing ground shaking hazard potential are the Toppozada and others(1988)planning scenario study for a major earthquake(magnitude 7+)on the Newport-Inglewood fault zone, and the Caltrans15 estimates of peak horizontal acceleration from maximum credible earthquakes(MCEs)for rock and stiff-soil sites. The Toppozada and others map 5-S(1988)shows the modeled seismic intensity distribution using the Modified Mercalli Intensity (MMI) scale standard (Table EH-2). The MMI intensity values presented are XI for the floodplain(gap)areas (a XI-+-along the fault zone) and an V111+ for the mesa areas. These intensities would undoubtedly be higher in the liquefaction prone areas. Mualchin and Jones (1992)published a map of peak horizontal ground acceleration(PGA) contours based on data through 1989. The City falls within a zone of 0.6g estimated PGA which is their highest contour level. Scientists of the U. S. Geological Survey and the Southern California Earthquake Center16 suggest that"When earthquakes occur directly beneath a city,it will be subjected to ground motions approaching the force of gravity[1.0g],exceeding the amounts of shaking anticipated by building codes in some respects." Table EH-1 shows deterministic values for the Newport-Inglewood of 1 g. (maximum credible) and 0.55g (maximum probable) using mean plus one sigma values" which better fit the Landers earthquake data for short distances from the fault.18 This suggests a range of 0.27g-0.55g for normal design considerations. 14 L.A.Times,October 21,1994;Science,October 21,1994. 15 Mualchin and Jones,1992,but updated only through 1989. 16 Science,October 21,1994. 17 Campbell,1993 m Blake,1993 update. 18 Campbell,1994. THE CITY OF HUNTINGTON .BEACH GENERAL PLAN V-EH-12 Exhibit"A"-Resolution No.2009-49 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT B. LIQUEFACTION The liquefaction susceptibility for the City is based on Tinsley and others (1985)who used occurrences of shallow water and alluvial deposits to define the areas shown on Figure EH-7 as very high,high,medium, and low. Liquefaction is the condition in relatively loose, saturated sandy sediments where internal shear strength is lost due to the repeated vibrations from earthquake shaking. Dynamic (seismically-induced) settlement can occur under these same conditions where sediments are only partially saturated. These types of failures have been observed in the 1933 Long Beach, 1971 San Fernando, and the 1994 Northridge earthquakes. Where alluvial areas have a surface slope of 0.5 to 5 percent,or more,flow failures and lateral spreading(a shallow landslide)can occur. C. TSUNAMI AND SEICIIE Tsunamis are long period, seismically generated sea waves caused by seafloor displacements (faulting or landslides). Previous evaluations19 put the tsunami hazards potential for the City at very low. The elevation of the run-up beyond the initial tidal elevation can be generally estimated from"maximum"past occurrence in California (estimated at 4-19 feet) from distant (South Pacific-South America-Alaska) or local (Santa Barbara Channel) earthquakes(Figure EH-8). Studies for the Bolsa Chica Project20 indicate 100-year and 500-year runup elevations of 5-6 feet and 7-9.5 feet,respectively. Sciches are generated by the"sloshing"of water in an enclosed or partially enclosed body of water caused by displacement within the water body, or more likely longer period earthquake motions. Of the most concern are seiches that are caused by tsunamis captured and reflected within the enclosed area of an inner harbor such as occurred in Los Angeles-Long Beach following the 1964 Alaskan earthquake. Huntington Harbour reported a 4-foot rise in water levels and damage to some moored boats. Seiche area damage would be most severe in the same areas as tsunami hazards. B. SUBSIDENCE The location of major oil drilling areas and state-designated oil fields are areas with subsidence potential; the pattern of subsidence (between 1-10 inches during 1976-1986) has been documented in an area corresponding roughly to the limits of the Huntington Beach Oil Field (Figure EH-9) with the maximum (about 5 feet) located roughly at the comer of Golden West Street and Pacific Coast Highway.21 Re- pressurization by injection(water flooding)has been used to stabilize this vertical Movement.22 ovement22 The rate of subsidence (about 0.6-1 inch/year) should diminish for fields with water flooding or re-pressurization programs;otherwise this rate could be continuing today. 19 Geotechnical Inputs,1974. 20 USACOE/City of Huntington Beach,1991 21 Morton and others.1976. 22 ANGUS Petroleum,1986;Division of Oil,Gas:R Geothermal Resources.1992. THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-13 Exhibit"A"-Resolution No.2009-49 Masonry A,8,C,D:To avoid ambiguity of language,the quality of masonry,brick or otherwise is specified by the following lettering. Masonry A: Goal workmanship,mortar and design;reinforced,especially laterally,and bound together by using steel,concrete,etc.;designed to resist lateral forces. Masonry B: Good workmanship and mortar;reinforced,but not designed in detail to resist lateral forces. Masonry C: Ordinary workmanship and mortar;no extreme weaknesses like failing to tie in at corners,but neither reinforced nor designed against horizontal forces. Masonry D: Weak materials,such as adobe;poor mortar;low standards of workmanship;weak horizontally. I. Not felt.Marginal and long-period effects of large earthquakes 11. Felt by persons at rest,on upper floors,or favorably placed. 111. Felt indoors.Hanging objects swing.Vibration like passing of light trucks.Duration estimated.May not be recognized as an earthquake. IV. Hanging objects swing.Vibration like passing of heavy trucks;or sensation of a jolt like a heavy ball striking the walls. Standing motor cars rock.Windows,dishes,doors rattle.Glasses clink.Crockery clashes.In the Upper Range of IV wooden wal Is and frame creak. V. Felt outdoors;direction estimated.Sleepers wakened.Liquids disturbed,some spilled.Small unstable objects displaced or upset.Doors swing,close,open.Shutters,pictures move.Pendulum clocks stop,start,change rate. VI. Felt by all.Many frightened and run outdoors.Persons walk unsteadily.Windows,dishes,glassware broken. Knickknacks,books,etc.,off shelves.Pictures off walls.Furniture moved or overturned.Weak plaster and Masonry D cracked.Small bells ring(church,school).Trees,bushes shaken visibly;or heard to rustle. VII. Difficult to stand.Noticed by drivers of motor cars.Hanging objects quiver.furniture broken.Damage to masonry D, including cracks.Weak chimneys broken at roof line.Fall of plaster,loose bricks,stones,tiles,cornices also unbraced parapets and architectural ornaments.Some cracks in masonry C.Waves on ponds;water turbid with mud.Small slides and caving in along sand or gravel banks.Large bells ring.Concrete irrigation ditches damaged. VI ll. Steering of motor cars affected.Damage to masonry C;partial collapse.Some damage to masonry B;none to masonry A Fall of stucco and some masonry walls.Twisting,fall of chimneys,factory stacks,monuments,towers,elevated tanks. Frame houses moved on foundations if not bolted down;loose panel walls thrown out.Decayed piling broken off. Branches broken from trees.Changes in flow or temperature of springs and wells.Cracks in wet ground and on steep slopes. IX. General panic.Masonry 0 destroyed;masonry C heavily damaged,sometimes with complete collapse;masonry B seriously damaged.General damage to foundations.Frame structures,if not bolted,shifted off foundations.Frames racked.Serious damage to reservoirs.Underground pipes broken.Conspicuous cracks in ground.in alluviated areas san and mud ejected,earthquake fountains,sand craters. X. Most masonry and frame structures destroyed with their foundations.Some well-built wooden structures and bridges destroyed.Serious damage to dams,dikes,embankments.Large landslides.Water thrown on banks of canals,rivers, lakes,etc.Sand and mud shifted horizontally on beaches and flat land.Rails bent slightly. Xl. Rails bent greatly.Underground pipelines completely out of service. XII. Damage nearly total.Large rock masses displaced.Lines of sight and level distorted.Objects thrown into air. 1. Odortal 1931 version in Wood,H.0.,and Neumann,f.,1931.Modified Mercalli intensity scale of 19315eismoiogical Society of America bulletin,v.53,no.5,p.979-987. 2. 1956 version prepared by Charles F.Richter,in Elementary Seismology,1958.p.137-138.W.H.Freeman&Co. SOURCE:Buena Engineers,Inc.Preliminary Geotechnical Engineering Report(May 19891 MODIFIED MERCALLI INTENSITY SCALE OF 1931 1, (1956 version)' m CITY Of HUNTINGTON BEACH GENERAL PLAN `- V-EH-14 Exhibit"A"-Resolution No.2009-49 a � J p v a ao cc a N cr F a w w z w a 0 WESTMINSTER SEAL BEACH BOLSA an: a S i $ Mc } FADDEN a z \ EDINGER HEIL WARNER < FOUNTAIN VALLEY TER 405 s 9 N O F COUNTYOF - O AL BEAT F e ORANGE CHIC •�l � K'Y J 0 e EL LIS Z Y O cr cr ¢ i. a a - - m- cr m 3 GARFI ELD YOR KT OWN - ADAMS NDIA POLL I NA S ATLANTA HAMILTON BANNING Legend e iYou COS TA City Boundary ry MESA f.. ..- -::-: L w n'Low Potential 1 to H-M High Medium{ ) 9 ed u Potential H-VHHI9h to VeryHi High Potential (VH)Veryh Potential 9 Hi Source:Tinsley,J.C.and others IM USGS Professional Paper t360,Fig ure 148 LIQUEFACTION POTENTIAL ®� CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-15 Exhibit"A"- Resolution No.200949 2 ¢U J 2 p SEAL + WESTMINSTER BEACH —. BDLSA� o .—.�. � I EDINGER .` HEIL —� ` WARNER FOUNTAIN ------. VALLEY SLATER 405 O� TALBERT ELLIS � •— —m — GARFIELD z % Y()RIQDWN phi ,ADAMS AL INDIANV iS PACIFIC , OCEAN I ATLANTA s� I HAMILTON - BANNING COSTA MESA LEGEND City Boundary Moderate Tsunami Run-Up Area MODERATE TSUNAMI RUN-UP AREA CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-16 Exhibit"A"- Resolution No.2009-49 m � a W SEA I I WESTMINSTER BEACH j I30l.SA• -- j � . f — FADI •—O EDINGER _ HEIL ' WARNER FOUNTAIN j VALLEY • 405 ` •SLATER ' NTY OF •`. TALBERT GO GE Hi ELL • — — ' GARFIELD % YORKTONN Kli- ADAMS NOIN4APOUS z I ATLANTA 3 p PACIFIC , _ I OCEAN / HAMILTON BANNING COSTA MESA Legend CHyr Boundary SOURCE Orap Count''Sunr M office;from Angus PMro wn 19K Appe&2,page 33 F� SUBSIDENCE AREAS FROM 1976-1986 55+9 CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-17 Exhibit"A"-Resolution No.2009-49 HAzARDs CHAPTER Environmental Hazards Element E. METHANE Figure EH-10 indicates the areas that have been affected by methane gas and have been designated as Methane Overlay Districts. Huntington Beach was identified as a high-risk area relative to methane gas migration into and/or from the shallow geology (peat and organic) deposits in the Roberti Report which discussed several oil fields.23 A later study by GeoScience Analytical24 indicating biogenic methane lead to the City enactment of methane seepage district regulations for these areas. All oil fields are considered high risk areas for methane seepage. The main conduit for petrogenic methane is through abandoned oil wells. Therefore,all areas which he above or in the immediate vicinity of one of the identified major oil field areas or drilling areas in the City are potentially areas of concern. Methane may also be trapped beneath impervious surfaces (e.g., parking lots) or in enclosed underground areas (e.g., basements, subterranean garages,tunnels)where concentrations may cause an explosion or hazardous breathing conditions. F. FLOODING The Federal Emergency Management Agency(FEMA) has evaluated the City of Huntington Beach for its potential to experience flooding. Bolsa Chica and Huntington Beach Mesas have been determined to experience minimal flooding during major rainstorms. The northern part of the City would be subject to flood depths of one to three feet (Figure Eli-11). The area of greatest flooding would occur in the Santa Ana gap between Huntington Beach Mesa and Newport Beach Mesa. Estimated flood elevations in this area are described as an elevation rather than a depth. Depending upon the location within that area, flood depth could be between three and six feet. Flood depths of seven feet would occur along the beach. Areas of localized flooding could reach depths exceeding nine feet. Flooding will affect several government and public facilities and numerous private residences and commercial operations. The sewage treatment plant, fire stations,major highways,high schools,elementary schools, Southern California Edison Plant, major utility corridors, several neighborhood and community commercial centers,and thousands of private residences would be adversely affected. G. OTHER GEOLOGIC AND SOILS ENGINEERING HAZARDS Geologic and soils conditions vary across the City. Conditions include expansive(Figure EU-12) and compressible soils, hydroconsolidation-prone sediments, peat (figure EH-13) and other poor foundation materials,highly erosive deposits,and steep topography. Peat and organic soils occurrences are estimated to be quite widespread in the City in former marshes and closed depressions where quiet water and vegetation were abundant. Peat and organic soils are highly susceptible to large long-term settlements due to their low density. Potential landslide areas within Huntington Beach are limited to those areas near the mesa bluffs, although no historical problems associated with landslides have occurred in the area. Thorough geologic investigations will be important in this area prior to development to insure slope stability. 23 ANGUS Petroleum.1988. 24 ANGUS Petroleum.1988, THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-19 Exhibit"A"- Resolution No.200949 U y [¢Jp) m � � W F, f�lya!! SEAL I / f•, WESTMINSTER BEACH BOLSA — �• _— z FADDEN T � . — — EDINGER ita - - HEIL •—` WARNER • FOUNTAIN --•-- VALLEY Tu .:. 405 •SLATER •�• •�•� I sy�o�co �• CO IUNTY OF ORANGE •ratter (BOLSACHICA) •✓ ' y .-ELLIS s$ •`• •— — — — ' GARFIELD IYORI(TOWN ADAMS PACIFIC INDIANAPOLIS OCEAN F $yam ATLANTA a #� HAMILTOH BANNING COSTA MESA �h- Legend r x � 3 City Boundary Methane Oveday District ; Source:C)oiHuntagton Beack 19W,Draft Set*Element Update,Fgure 6.3.1 METHANE OVERLAY DISTRICTS 9 65 10Im 40 CITY OF HUNTINGTON BEACH GENERAL PLAN uri V-EH-19 Exhibit"A"-Resolution No.2009-49 U J � 2 [J p SEAL I..:::::•--''::_ =:::;�:. WESTMINSTER BEACH SOLSA•. — Y UN p ¢ Z FADDEN Depth <1' Z EDINGER r,-• HELL Minimal = Floodin = c.v R waRNE FOUNTAIN '-•• •�"•• •'••�::Depth< V VALLEY 405 •` .SLATER �. COUNTY OF I TALBERT ORANGE MCHP to y I ELLIS k1 Minimal — ' Floodin voRKrowN PACIFIC OCEAN A�tr AoaMs i INDIANAPOLIS ATIANTA LEGEND / NatruuoN r Cdy Boundary ' BANNING � r.c Wimal Flooding COSTA MESA Depth<1' � Depth 1-3' � a ; Flooding with Wave Acdon t SOURCE:FEMA,1996 100&500 YEAR RAIN FLOOD LEVEL 051-1 1 CITY OF HUNTINGTON BEACH GENERAL PLAN Mort V-EH-20 Exhibit"A"- Resolution No.200949 U W � e � j SEAL WESTMINSTER BEACH B" o � m Y ? MC g o FADDEN EDINGER HEIL WAMER FOUNTAIN VALLEY 405 •`'� COUNTY OF •�. TABERT • ORANGE ! GA1iMD - roPocrowN ADAMS PACIFIC NDIANAPOLIS ATWA PAMM Legend BANNING � : r= City Boundary FRO COSTA Moderate to High(20°A-42%) MESA is Low to Moderate(6°A-27%) 4 Low(7%or Less) Variable ,_ Sowce: City o1 Huntington Beach,1974,Geotechn�inputs � �"`����''� ��. (btlteSeh*Safe Beffw4FIgute38 EXPANSIVE SOIL DISTRIBUTION MAP CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-21 Exhibit"A" -Resolution No.2009-49 E�M't j -- c? ADAM q BE PROINW LOCA)ON OF PEAT I; (AMA&OEPIH WK OA N) � ®VITO 6THICK UO't32 OF PEN. $10 25 MCK UM OF PEAT EM OM 25MM LMM OF PEN M MARSH-19255,1906;01Z19O p,HMRM BOUNDARY / Source:CkyoFHuntington Beach,1974,Geotechnical Inputs ito the Seink Safety Element),Figure 3-7 PEAT AND ORGANIC SOILS W ° 3'°°° s'�° Z ®� CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-22 Exhibit"A" Resolution No.2009-49 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT Soil erosion in Huntington Beach ranges from a slight to a high hazard. With proper ground cover and drainage controls,the erosion is minimized. The seaward facing bluffs of Huntington Beach are subject to erosion during periods of extremely high tides. If beach sand replenishment has not maintained an adequately wide beach and the beach has narrowed due to the net loss of sand, the bluffs would be susceptible to ocean flooding and wave erosion endangering structures and people on the overlying mesa surface. The perched(shallow)water table is high throughout the entire City of Huntington Beach. Most of the soils also cause water to percolate very slowly downward into deeper layers so any water entering the soil tends to remain fairly near the surface,or in local ponds. Each of these other conditions represents a potential hazard that is routinely evaluated by standard soils and foundation engineering and testing required by City of Huntington Beach grading and building codes. These hazards are to be considered on a site-specific basis as projects within the various areas of the City are initiated. ISSUES 1. The City of Huntington Beach lies astride segments of the Newport-Inglewood fault zone which have been determined to have fault rupture potential. These segments pass beneath existing developed areas and areas which would be developed under the General Plan. (EH 1.1.1,EH 1.1.2, EH 1.1.3, EH 1.2.1,and EH 1.2.2) 2. Due to Huntington Beach's location to the Newport-Inglewood fault zone, strong shaking may be higher than many other areas.(EH 1.1.1,EH 1:1.2,EH 1.1.3,EH 1.2.1 and EH 1.2.2) 3. Due to the high water table condition and the tightness of the subsoils of Huntington Beach, liquefaction and seismically induced settlement may be experienced in many areas of the City during strong earthquakes.(EH 1.1.1,EH 1.1.2, and EH 1.2.1) 4. Due to the location on the coast the City is subject to potential run-up and tsunami damage from both distant and locally generated tsunamis,although past experience indicates that this potential is low. Seiche damage would likely be associated with a tsunami.(EH 5.1.1. and EH 5.1.2) 5. The failure of Prado Dam near the head of Santa Ana Canyon poses a flooding threat to the City which would only be realized if this flood control basin were nearly full during the causative earthquake. (EH 4.1,1,EH 4.1.2,EH 4.2.2, and EH 4.2.4) 6. Erosion of soils left barren of vegetation can occur due to agents such as wind and rain. Proper vegetative cover and drainage will limit the amount of erosion to a level of insignificance. (EH 1.1.1 and EH2.2.1) 7. The rate at which water can percolate into the soil varies amongst the soils of Huntington Beach, but is generally slow. Long term ponding of water during heavy rains or long term periods of precipitation is likely,in some areas. (EH 1.1.1 and EH 4.1.1) 8. Expansive soils of Huntington Beach vary in their shrink-swell characteristics. Soils with a high shrink-swell potential may produce damage to overlying structures as they experience changes in moisture levels associated with periods of rains and droughts. (EH 1.1.1) THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-23 Exhibit"A"-Resolution No.2009-49 HAZARDS CHAPTER Environmental Hazards Element GOALS,OBJECTWES,AND POLICIES EH 1.1.4 Evaluate the levels of risk based on the nature of the The following section presents the goals, objectives, hazards and assess acceptable risk based on the policies,and programs for Environmental Hazards in the human,property,and social structure damage City of Huntington Beach At the end of each policy is a compared to the cost of corrective measures to reference to the appropriate implementation program. mitigate or prevent damage.(I--EH 3 and I--EH 4)27 Each implementation program's schedule and possible funding sources are indicated in the Environmental Objective Hazards Implementation Matrix. EH 1.2 Ensure that new structures are designed to❑munize Geolo>:ic/Seisndc Safety damage resulting from seismic hazards,ensure that existing unsafe structures are retrofitted to reduce Goal hazards and mitigate other existing unsafe conditions. EH 1 Ensure that the number of deaths and injuries, Policies levels of property damage, levels of economic and EH 1.2.1 social disruption,and interruption of vital services Require appropriate engineering and building practices resulting from seismic activity and geologic for all new structures to withstand ground shaking and hazards shall be within levels of acceptable risk." liquefaction such as stated in the Uniform Building Code(UBC). (I-EH S) Objective EH 1.2.2 EH 1.1 Establish specific priorities for improvement of Ensure that land use planning in the City accounts for existing structures based on hazard to life,type of seismic and geologic risk, including ground shaking, occupancy,method of construction,physical condition, liquefaction, subsidence, soil and slope stability, and and location.(I-EH 4 and I-EH 6)" water table levels. �/ EH 1.23 Policies Rectify improperly abandoned water wells. (I-EH 7) EH 1.1.1 Maintain a complete database of the location and EH 1.2.4 distribution of seismic and geologic hazards related to Support the education and dissemination of ground shaking,liquefaction,subsidence,soil stability, information about the potential environmental hazards slope stability and water table levels. (I-EH 1,I-EH 2 that may exist in Huntington Beach. (I-EH2 and I-EH and 1--EH 3) 8) EH 1.1.2 Objective Support land use patterns, Zoning Ordinances'21 and EH 13 locational criteria that mitigate potential risks posed by Enhance emergency preparedness through community development in hazard areas, or which significantly education,effective emergency response and efficient reduce risk from seismic hazards. (I-EH 3, I-EH 4, post-disaster recovery. and I--EH 5) Policies EH 1.13 EH 13.1 Require seismic/geologic assessment prior to Ensure that all citizens have access to information construction in Alquist-Priolo Earthquake Fault Zone regarding local environmental hazards,emergency as shown in Figure EH-5.(I-EH 3 and I-EH4) preparedness,and emergency response. (I-EH I and I-EH 8) 2'Mitigation Measure GS-2 as specified in EIR No,94-1,Table EX-1 27 Mitigation Measure GS-4 as specified in EIR No.94-1,Table 26 Mitigation Measure GS-3 as specified in EIR No.94-1,Table EX-1 EX-1 21Mitigation Measure GS-5 as specified in EIR No.94-1,Table EX- THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-24 Exhibit"A"- Resolution No.200949 HAzARDs CHAPTER ENVIRONMENTAL HAZARDS ELEMENT EH 1.3.2 EH 2.1.2 Maintain and regularly update emergency plans for Minimize beach sand loss. (I-EH 1) earthquake response.(I-EH 2,I-EH 9,and I-EH 10) Objective EH 1.33 EH 2.2 Provide the Emergency Operations Center with Increase public safety from erosion hazards through information regarding seismic/geologic hazard public awareness and education.(I-EH 1, I-EH 2 and locations. (I-EH 2) I-EH 8) EH 13.4 Policies Require that earthquake survival and efficient post EH 2.2.1 disaster functioning be a primary concern in the siting, Provide information to the public regarding erosion design,construction,operations,and retrofitting areas and emergency response plans. (I-EH 1,I-EH 2 standards for critical,essential,and high occupancy and I EH 8) facilities,including public safety facilities.(I-EH 2 and I-EH 9)29 Methane EH 1.3.5 Goal Encourage property owners to take adequate steps to EH 3 protect their property against economic risks resulting Ensure the safety of the City's businesses and from seismic and geologic hazards. (I-EH 2)" residents from methane hazards. Erosion Objective EH 3.1 Goal Identify areas within the City most prone to methane EH 2 gas seepage and buildup. Reduce the potential for mesa edge and bluff Policies erosion hazards,and the potential for beach sand EH 3.1.1 loss.31 Continue to establish, through the identification of Methane Overlay Districts, areas of existing methane Objective seepage in the City as shown in Figure EH-10.(I-EH EH 2.1 1) Ensure that land use planning and City policy account for bluff and coastal sand erosion. EH 3.1.2 Continue to investigate and evaluate new sources of Policies methane.(I-EH 1 and I-EH 11) EH 2.1.1 Minimize bluff and mesa edge32 erosion. (I--EH I and Objective I-EH 4) EH 3.2 Minimize methane hazards in the identified Methane Overlay District, and other areas outside the Methane Overlay Districts as may later be defined,through the regulation of construction and adherence to the City's Methane Hazard Mitigation Plan." 29 Mitigation Measure GS-6 as specified in EIR No.94-1,Table EX-1 30 Mitigation Measure GS-7 as specified in EIR No.94-1,Table EX-1 31 Mitigation MeasureGS-9 as specified in EIR No.94-1,Table EX- 1 32 Mitigation Measure GS-10 as specified in EIR No.94-1,Table �3 Mitigation Measure GS-13 as specified in EIR No.94-1,Table EX-1 EX-I THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-25 Exhibit"A"-Resolution No.2009-49 HAZARDS CHAPTER Environmental Hazards Element Policies. Increase public safety from methane hazards through EH3.2.1 public awareness and education. Maintain and revise as necessary, standards of construction within identified Methane Zones.34 (I-EH Policies 4 and I--EH6) EH3.4.1 Provide information to the public regarding methane EH 3.2.2 areas and emergency response plans. (I--EH 8) Establish, enforce, and periodically update3s testing requirements for sites proposed for new construction Floo&m>� within the identified Methane Overlay District. (I-EH 12) Goal EH 4 EH 3.2.3 Eliminate, to the greatest degree possible, the risk Provide mitigation measures and other assistance from flood hazards to life, property, public intended to reduce the potential for the buildup of investment and social order in the City of methane to hazardous levels within existing buildings Huntington Beach. (residences and businesses). 36 (I--EH 2, I-EH 4 and I-EH 8) Objective EH 4.1 EH 3.2.4 Ensure that the City's flood prevention standards and Remain current on new technologies, policies, and practices provide satisfactory safeguards for public procedures to fiuther protect against a major methane and private development. related catastrophe.37(I-EH 2 and I-EH 8) Policy Objective EH 41.1 EH 3.3 During major redevelopment or initial construction, Maintain knowledge of methane levels and require specific measures to be taken by developers, preparedness for the provision of emergency services. builders or property owners in flood prone areas (Figure EH-11), to prevent or reduce damage from Policies flood hazards and the risks upon human safety. (I-EH EH 3.3.1 1,I EH 2,I-EH 4, and PEH 1 S) Monitor methane levels in the identified Methane Overlay District. (I-EH 1) EH 4.1.2 Establish and enforce standards which minimize EH 33.2 financial loss and maximize protection of residents and Prepare emergency response plans for use in methane business owners'property. (I-EH 1,I-EH 2,I-EH 14, related emergencies_ (I-EH 13) and I-EH 1 S) EH 3.3.3 Objective Conduct periodic training of Fire Department and EH 4.2 other appropriate emergency personnel on procedures Maintain and upgrade, as appropriate, the County of in the Methane Hazards Mitigation Plan 38(I-EH 2 and Orange and the City of Huntington Beach's flood I-EH8) control systems in conjunction with the Santa Ana Objective River Main Stem Project to minimize hazards due to EH 3.4 flooding. 34 Mitigation Measure GS-14 as specified in EIR No.94-1,Table EX-1 35 Mitigation Measure GS-15 as specified in EIR No.94-1,Table EX-1 36 Mitigation Measure GS-16 as specified in EIR No.94-1,Table EX-1 37 Mitigation Measure GS-17 as specified in EIR No.94-1,Table EX-1 31 Mitigation Measure GS-18 as specified in EIR No.94-1,Table EX-1 THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-26 Exhibit"A"-Resolution No.2009-49 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT Policies Policies EH 4.2.1 EH 5.1.1 Support the Santa Ana River Main Stem Project. Identify tsunami and seiche41 susceptible areas, and (I-EH 2 and I--EH 16) require that specific measures be taken by the developer, builder, or property owner, during major EH 4.2.2 redevelopment or initial construction, to prevent or Increase the local storm drain and flood control reduce damage from these hazards and the risks upon capacity up to meet 100-year the demand of a storm. human safety(see Figure EH-8). (I-EH 1 and I-EH (I-EH I and I-EH 2) 4) EH 4.23 EH 5.1.2 Coordinate with the County of Orange for the Participate in the National Weather Service or other operation of the County's portion of the flood control system for local tsunami and/or seiche42 warnings. system. (I-EH 2) (I-EH 17) EH 4.2.4 Objective Maintain the City's portion of the flood control system EH 5.2 at a level necessary to protect residents from 100-year Increase public safety from tsunami hazards through flood risks. (I-U 1,I-U3,I-U4, and I-EH2) Public awareness and education. Objective Policies EH 43 EH 5.2.1 Protect individuals from physical harm in the event of Provide information to the public regarding tsunami flooding. areas and emergency response plans. (I-EH 8 and I- EH 13) Policy EH 43.1 Peat Provide sufficient early warning and evacuation assistance to residents and others in the path of Goal flooding. (I-EH 13) EH 6 Ensure the safety of the City's businesses and Tsunami residents from peat hazards. Goal Objective EH 5 EH 6.1 Protect human life, to the greatest extent feasible, Identify areas within the City most prone to peat from tsunamis and seiche hazards.39 conditions. Objective Policy EH 5.1 EH 6.1.1 Provide information regarding tsunami, seiche, 40 and Maintain a thorough knowledge of the location and tidal/marine hazards, and promote methods to distribution of peat conditions in the City of minimize potential damage. Huntington Beach(Figure EH-13). (I-EH 1) Objective EH 6.2 Minimize peat hazards through the regulation of construction. (1-EH 4) 39 Mitigation Measure SD-1 as specified in EIR No.94-1,Table 41 Mitigation Measure SD-3 as specified in EIR No.94-1,Table EX-1 EX-1 4°Mitigation Measure SD-2 as specified in EIR No_94-1,Table 42 Mitigation Measure SD-4 as specified in EIR No.94-1,Table EX-1 EX-1 THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-27 Exhibit"A"- Resolution No.2009-49 HAZARDS CHAPTER Environmental Hazards Element Policy comprehensive mapping of groundwater EII 6.2.1 potential hazard areas in the City; Establish standards of construction within identified peat zones. (I-EH 4} comprehensive mapping of peat potential hazard areas in the City; Objective challenges to flood zone boundaries that EH 63 appear to be unreasonable or incorrect; Increase public awareness about the location and a Local Drainage Master Plan assessing hazards of peat conditions. (I-EH 8) improvements necessary to achieve 100-year capacity for the local flood Policy control system; ER 6.3.1 Provide information to the public regarding peat request that the Orange County Surveyor condition areas and proper construction methods and update its Subsidence Book report standards. (TEH8) through 1993 for the Pacific Coast Highway, Huntington Beach Pump All hazards station, and Huntington Beach. The City shall perform an evaluation of the Goal data to assess possible subsidence at the EH 7 oil field and drilling areas underlying the Ensure the safety of the public, to the greatest City. Based on the results of this extent feasible, from the impacts of a natural evaluation a mitigation program for disaster. reducing the potential hazards shall be prepared for use by the City," Policy a Grading and Geotechnical EH 7.1.1 Investigation Guidelines manual which Maintain and update as necessary the current local will outline the minimum proper soils Hazards Mitigation Plan (HMP) as part of the engineering and engineering geologic Environmental Hazards Element. The HMP includes study for all sites where grading will resources and information to help reduce risks and occur. Topics shall include, but not prevent losses from future natural disasters. (I-EH 1) necessarily be limited to, soils engineering and foundations, erosion IMPLEMENTATION PROGRAMS control, peat and organic soils, slope stability, erosion, liquefaction and I-EH I dynamic settlement, shallow ground Studies/MaupinWMaster Plans water, and fault location/activity. This a. Conduct, prepare and/or update the following manual shall be available at the permit as funding permits: stage prior to initial feasibility and • design studies in order to enhance the comprehensive mapping of development review and seismic/geologic hazard areas in the environmental review processes;"' City, including fault locations, unstable soils and slope locations, areas of high a Methane Hazards Guidance manual liquefaction potential, areas of high which will outline methane overlay seiche potential and locations of shallow districts, standards of construction, water table depth; definition of additional hazards areas, and hazard mitigation. This manual • maps of potential bluff erosion areas; shall be available at the permit stage • maps of existing methane seepage areas; prior to initial feasibility and design methane level monitoring on an studies in order to enhance the on-going basis; 41 Mitigation Measure GS-20 as specified in EIR No.94-1,Table • comprehensive mapping of flooding EX-1 potential hazard areas in the City; 44 Mitigation Measure GS-1,GS-8,and GS-19 as specified in EIR No.94-1,Table EX-1 THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-28 Exhibit"A"- Resolution No.2009-49 HAzARDs CHAPTER ENVIRONMENTAL HAZARDS ELEMENT development review and environmental b.Continue to: review processes,45 evaluate methane sources, locations and • an assessment of potential damage to concentrations on a site-specific basis essential utility and transportation and will include any previously infrastructure and public service unidentified methane areas in the facilities due to geologic/seismic Methane Overlay District; hazards. The findings of the assessment assume the lead role in mitigating should be utilized in the review of methane hazards in public rights-of-way proposed development projects, and used for maintainingand u and on public property; 46 I��g s lement beach sand with sand from emergency preparedness plans; uPP • standards for tsunami/seiche studies to outside sources;and be completed for harbor areas, work with property owners to maintain breakwaters, and coastal areas of safe conditions on their property. concern. The City shall update its c. Use the EHE and the data from items a)and b) evaluation of the tsunami hazard, make above to prepare and submit a formal update of its standards more specific, and the seismic safety components of the Safety disseminate available information on Element requirement 49 tsunami warnings and on procedural steps to prepare the populous for such an d. The City's EOC will maintain, review and event. Mitigation measures shall be update, as necessary,the current local Hazards suggested for new construction;47 Mitigation Plan. • determine the safety status of all dams I-EH 2 which may fail and cause inundation Interagency Participation and Coordination within the City. This shall be done in cooperation with the County of Orange a. The Emergency Operations Center(EOC) will and the State Division of Safety of Dams coordinate with the Departments of Police, in order to establish the safety status and Fire, Public Works, Community Development, to determine what follow up analyses,if Community Services and other departments in any,are needed. Based on these results, preparing and maintaining earthquake and other the City shall develop risk guidelines emergency response plans. and to allow evaluation of current b. The City will provide the EOC with maps of regulatory measures for protection of seismic/geologic hazard areas in the City, future development;48 including fault locations, areas of high • operational strategies for the City's liquefaction potential and areas of seiche portion of the local flood control system hazard. intended to maximize system efficiency c. The City will work with and coordinate its and minimize system overload during earthquake and other emergency response plans periods of heavy rainfall;and with each school district as the school districts • a hazardous waste sites map within the prepare earthquake education programs and City, develop their own earthquake and other emergency response plans. d. The EOC will coordinate with the Building Division and the Department of Public Works to establish standards for the design and operation of public safety facilities which will 45 Mitigation Measure GS-I I as specified in EIR No.94-1,Table ensure that they remain safe and functional EX-1 46 Mitigation MeasureGS-24 as specified in EIR No.94-1,Table during and after disasters. EX-1 47 Mitigation Measure SD-5 as specified in EIR No.94-1,Table EX-1 48 Mitigation Measure SD-6 as specified in EIR No.94-1,Table - 49 Mitigation Measure GS-21 as specified in EIR No.94-1,Table EX-I EX-1 THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-29 Exhibit"A"- Resolution No.200949 HAzARDs CHATTER Environmental Hazards Element e. The EOC will coordinate with the Fire d. drainage plans addressing bluff erosion for all Department to establish and maintain an future bluff top developments; emergency response mutual aide agreement e. the continued evaluation of all proposals for with other public agencies. new construction within the Methane Overlay f. Work with FEMA to clarify, simplify and District be evaluated for necessary special interpret the floodplain development standards construction methods; in a way that benefits property owners in the f. that proposed critical, essential, and high- City. occupancy facilities be subject to seismic g. In conjunction with the Santa Ana River Flood review,including detailed site investigations for Protection Association(SARFPA),the City will faulting, liquefaction, ground motion lobby County, regional, state and federal characteristics, and slope stability, and governments for funding support for the Santa application of the most current professional Ana River Main Stem Project. standards for seismic design-" It. Coordinate with the Orange County g. that proposed projects located in the tsunami Environmental Management Agency to hazard areas(Figure EH-9): improve the County portion of the local flood are designed to minimize beach/bluff control system up to 100-year storm capacity. erosion and the need for sand I-EH 3 replenishment along city beaches;and Alquist-Priolo Earthquake Fault Zone consider design options which reduce the potential for damage to private a. Continue to implement the Alquist-Priolo property and threats to public safety,i.e., Earthquake Fault Zone requirements. raised foundations,ground floor parking b. Implement the fault classification system with upper level uses. suggested by Leighton&Associates(April 17, 1986) with regard to faults in the City I-EH 5 susceptible to fault rupture, and establish a Ordinances study requirement based on risk and structure a. Enforce the most current Uniform Building importance. code adopted by the State of California. I-EH 4 b. Prepare ordinances prohibiting the location of Development Review or Environmental Review critical or sensitive facilities or high occupancy Process facilities within a predetermined distance of an During development review(site plan,tract map,etc.) active or potentially active fault. and/or environmental review,require: I-EH 6 a. building structures proposed in liquefaction, Unsafe Structures Retrofitting or Demolition unstable soil/slope conditions, flood prone a. Continue to implement and enforce the City's areas, high water tables,peat or other geologic earthquake hazard regulations as outlined in the hazards prone areas to determine potential Municipal Code. problems and to require mitigation measures; b. Devise measures to retrofit existing structures b. a potential seismic/geologic damage assessment for methane protection. be conducted for essential public utilities (gas, water, electricity, communications, sewer) and I-EH 7 require that appropriate mitigation measures be Groundwater Mitigations incorporated; Mitigate, or require property owners to mitigate, c. critical or sensitive facilities and uses to be groundwater problems related to improperly located in areas where utility services and abandoned water wells. continuous road access can be maintained in the event of an earthquake; 50 Mitigation Measure GS-22 as specified in EIR No.94-1,Table $i Mitigation Measure GS-23 as specified in EIR No.94-1,Table EX-1 EX-1 THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-30 Exhibit"A"- Resolution No.200949 HAZARDS CHAPTER ENVIRONMENTAL HAZARDS ELEMENT I-EH 8 that it was abandoned incorrectly or prior to current Public Education standards. a. The EOC will increase the development and use of verbal and written education tools Methane Gas Testing Standards and Requirements including lectures and illustrations offered Met through cable television, clubs, public and private schools, neighborhood groups; service a. Coordinate with the Building Division to organizations, youth groups, business establish methane mitigation construction organizations and any other interested groups standards such as venting systems,impermeable or organizations, regarding earthquake barriers and iocational criteria. preparedness. The information will include b. Maintain testing standards and requirements for emergency services available and strategies for new construction sites in the Methane Overlay survival and self-sufficiency in the days District. Completion of the tests and the test following an earthquake. results will be required prior to development b. Provide technical guidance and direction to review. private businesses and residents found to have methane seepage or buildup on their property. I-EH 13 c. Maintain and provide methane emergency Emergency Contingency Plans response plans to the public. a. Coordinate with the EOC to prepare a Methane d. Maintain floodplain and erosion information Emergency Contingency Plan including early available to the public. warning procedures, an evacuation plan and emergency methane hazard mitigation e. Maintain peat information available to the measures. public. b. The City's EOC will maintain flooding I-EH 9 contingency plans which provide for early Staff Training warning, evacuation assistance, as needed, and damage assessment after the event. Continue to implement City employee emergency training drills. c. Continue to support, assist and expand the Community Emergency Response Team I-EH 10 (CERT). Disaster Recovery Committee d. Coordinate with local school districts in the Establish a Disaster Recovery Committee which will preparation of emergency contingency plans, include representatives from EOC,Planning,Building, including early warning procedures,evacuation Public Works,Fire,Police,local utility providers and plans,emergency facility and shelter utilization, local emergency medical providers. This committee and emergency services availability. should participate in planning for post disaster assessments, rapid reconstruction, emergency housing I-EH 14 and emergency funding and shall develop guidelines Flood Insurance Programs defining"chain of command"and responsibilities. a. Participate in the National Flood Insurance Program in a manner that provides the most I-EH 11 financial and physical protection to residents Abandoned Oil Well Re-Evaluation and property owners in the City while Establish a program to re-evaluate the safety and status minimizing costs to them. of abandoned oil wells within the City, pursuant to b. Participate in the FEMA's Community Rating Public Resources Code Section 3208.1. `z The plan System to reduce flood insurance premiums for should specify that reevaluation should occur during property owners in the City. major redevelopment or initial construction on the site of an abandoned oil well when it can be determined 52 Mitigation Measure GS-12 as specified in EIR No.94-1,Table EX-I THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-31 Exhibit"A"-Resolution No.200949 HAZARDS CHAPTER Environmental Hazards Element I-EH 15 FEMA Development Standards Adopt and enforce the most recent floodplam development standards promoted by the Federal Emergency Management Agency(FEMA). I-EH 16 Santa Ana River Main Stem Funding Pursue local.funding to contribute to the Santa Ana River Main Stem Project. I-EH 17 Local Tsunami Warnings Wire System Use the Weather Wire's information from the National Weather Service or other appropriate warning systems to detect and warn of tsunami occurrences and other weather conditions in the region. This system should be monitored by the Marine Safety Division, which presently receive daily reports on weather conditions for marine operations. This warning system should be incorporated into the City's Emergency Preparedness Plan. THE CITY OF HUNTINGTON BEACH GENERAL PLAN V-EH-32 Exhibit"A" - Resolution No.2009-49 ADMINISTRATION ' m m 1,51 .t5@�3 t �Ei 3 '- Qi cs c' o rn` ot`o a '. �' a; a; I Q; -; u �s o; E: E; E! o 13 Ei �i•'ia, o c ms; O 8 � a o 3 0: m A f3' o m "� {.�€ '3 8i No. Name CnY OF HUNTINGTON BEACH CITY OF HUNTINGTON REACH PROGRAM RESPONSIBLE AGENCY FUNDINGSOURCE scHeouLE i EH-1 jStudiesfMapping/MasterPlans ®_ ® ®' ® -_- - - • — •` • • Ongoing' EH-2 Interagency Participation and Coordination ® • j• ® ® _ ® —_t._. - Ongoing - EH-3 Nqulst-Priolo Earthquake Fault Zane •' 1. ! • j Ong' EH-4 i Development Review or Environmental Review Process • i F • , •'• + • Ongoing' EH-5 Ordinances ®! • • • ` I Ongoing'` EH$ ;Unsafe Structures Retrofitting or Demolition •l - • ' -- - Ongoing' ---`--=--a- --=-- - -- - - ;--- -- - -= - - ---- t.EH-7 Groundwater Mitigations j , ; i • • ' � ongoing EH-8 ;Public Education • i •{ • _ • • - Ongoing EH-9 Staff Training ®` ®:• •s'• • • i • • I Ongoing EH-10 I Disaster Recovery Committee • ; • • • • • - ongoing' EH-1 1 Abandoned Oil Well Re-evaluation •9 i o rt •€ i- -Ongoing' EH-12 Methane Gas Testing Standards and Requirements • { ; • •~ • ongoing' - - —t- -- - - - ----i-- - - -- EH-13 Emergency Contingency Plans • • • • !• ® _ Ongoing EH-14 Flood Insurance Programs ® ; { ! • ® • Plan ,. EH-15 FEMA Development Standards • :• • i • ; i —( Ong' EH 16 Santa Ana River Main Stem Funding • I { • j ® • ° I Ongoing* EH 17 Local Tsunami Warnings Wire System ; • � � i � ® : ' � Ongoing "As funding permits ENVIRONMENTAL HAZARDS IMPLEMENTATION PROGRAM MATRIX a CITY OF HUNTINGTON BEACH GENERAL PLAN E I V-EH-33 Res. No. 2009-49 STATE OF CALIFORNIA COUNTY OF ORANGE ) ss: CITY OF HUNTINGTON BEACH ) I, JOAN L. FLYNN the duly elected, qualified City Clerk of the City of Huntington Beach, and ex-officio Clerk of the City Council of said City, do hereby certify that the whole number of members of the City Council of the City of Huntington Beach is seven; that the foregoing resolution was passed and adopted by the affirmative vote of at least a majority of all the members of said City Council at a regular meeting thereof held on September 8, 2009 by the following vote: AYES: Carchio, Dwyer, Green, Bohr, Hardy, Hansen NOES: None ABSENT: Coerper ABSTAIN: None Clerk and ex-offici Clerk of the City Council of the City of Huntington Beach, California