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Home My WebLink AboutCity Council - 2000-85 RESOLUTION NO. 2000-85 A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF HUNTINGTON BEACH APPROVING THE FLOOD MANAGEMENT PLAN FOR THE CITY OF HUNTINGTON BEACH WHEREAS, Huntington Beach has several areas of the City that have experienced repetitive flooding that results in hazards to public health and safety and serious property damage; and On November 1, 1999, the City Council directed the preparation of a flood management plan; and City Council's objective was to prepare a plan to reduce or mitigate flood damage within the City; and On April 6, 2000, following five months of biweekly meetings, the Flood Management Committee approved the recommended activities and directed staff to forward the draft Flood Management Plan for consideration and recommendation by the Planning Commission, and final adoption by the City Council; and The Planning Department has determined that the Flood Management Plan is covered by Environmental Impact Report No. 94-1 which was prepared for the General Plan and certified by the City Council in May 1994; and The Flood Management Plan has been reviewed at a duly noticed public hearing held by the Planning Commission of the City of Huntington Beach on August 8, 2000, and the Planning Commission recommended approval of the Plan by the City Council, NOW,THEREFORE, the City Council of the City of Huntington Beach does hereby find and resolve as follows: SECTION 1. The Flood Management Plan provides a strategy to: ■ Implement the goals, objectives, and policies of the General Plan; ■ Eliminate flood hazard risks to life,property, and public investment; ■ Provide a flood control system to support permitted land uses while preserving public safety; ■ Protect human life from tsunamis and seiche hazards; ■ Reduce bluff erosion and beach sand loss; ■ Preserve the City's open space; and ■ Promote preservation and restoration of historical resources. 1 4/s:4-2000 Resolutions: Flood Management Plan RLS 2000-717 8-17-00 Res. No. 2000-85 SECTOIN 2. The Flood Management Plan identifies potential flood hazards and methods to reduce or mitigate flood damage. SECTION 3. The Flood Management Plan.will assist local, state, and federal flood mitigation and planning efforts. SECTION 4. The Flood Management Plan will ensure that flood insurance premium reductions continue to be available to Huntington Beach property owners and tenants. SECTION 5. The Flood Management Plan satisfies the Federal Emergency Management Agency's requirement for the City's continued participation in the National Flood Insurance Program. SECTION 6. The City Council hereby finds that the public necessity, convenience, general welfare, and good zoning practice justifies the approval and implementation of the Flood Management Plan which is consistent with the City's General Plan. SECTION 7. On the basis of the finding set forth above in this Resolution, that said Flood Management Plan, a copy of which is attached hereto as Exhibit"A" and incorporated by this reference as though fully set forth herein, is hereby approved and adopted by the City Council of the City of Huntington Beach. PASSED AND ADOPTED by the City Council of the City of Huntington Beach at a regular meeting thereof held on the 5th day of September , 2000. Mayor ATTEST: APPROVED AS TO FORM: City Clerk 1-4-49 City Attorney �� 4-V � I I1�1I�� REVIE ED AND APPROVED: INIT TED AND APPROVED: pC,V4 City Administrator Director lanning 2 4/s:4-2000 Resolutions: Flood Management Plan RLS 2000-717 8-17-00 Res. No.2000-85 s� p� 1 n z. y69 v _ tiro�� \ fir ,�v :\ \ �\ *., \ ,� 'S \. \ �,�;�\•.�� \;,..\ `�:\�h;;�\ � v., � � Res. No.2000-55 CITY OF HUNTINGTONSEA AUGUST i 1 a Res. No.2000-85 TABLE OF CONTENTS Section Pape 1.0 PURPOSE AND INTRODUCTION 1 1.1 Purpose 1 1.2 Introduction 1 1.2.1 Floodplain Created 1 1.2.2 Flood Hazard Study 1 1.2.3 National Flood Insurance Program 2 1.2.4 Community Rating System 2 1.2.5 City Council Direction 3 2.0 FLOOD MANAGEMENT PLAN COMMITTEE 4 2.1 Committee Established 4 2.2 Committee Membership 4 2.3 Committee Meetings 4 3.0 COMMUNITY DESCRIPTION 6 4.0 HAZARDS 7 4.1 Weather Related Flooding 7 4.1.1 Tropical Storms 8 4.1.2 Heavy Rain 8 4.1.3 High Water Table/Wetlands 8 4.1.4 Tornados 8 4.2. Flood Control 9 4.2.1 Santa Ana River 9 4.2.2 Dam Failure 9 4.2.3 Flood Control Channels 11 4.2.4 Pump Stations 12 4.3 Pacific Ocean Activity 13 4.3.1 High Tides 13 4.3.2 High Surf 14 4.3.3 Beach/Bluff Erosion 14 4.3.4 Tsunami 14 4.4 Accidents 14 4.4.1 Reservoirs 14 4.4.2 Water maintfire Hydrant Breaks 14 4.5 Other Geologic Hazards 15 i - Res. No. 2000--85 5.0 HAZARD RELATED IMPACTS 16 5.1 Heavy Rain/Tropical Storms 16 5.1.1 Repetitive Flooding Areas 20 5.1.2 Repetitive Loss Properties 26 5.1.3 Santa Ana River History 27 5.2 High Tides and High Surf 28 5.3 Tornados 28 5.4 Buildings 29 5.4.1 Public Buildings 29 5.4.2 Historic/Local Landmarks 29 5.4.3 Critical Facilities 30 5.4.4 Hazardous Chemical Facilities 30 5.5 Wetlands, Undeveloped Properties, and Open Space Areas 30 5.6 Protective Measures in Effect or Under Construction 31 5.6.1 Santa Ana River Mainstem Project 31 5.6.2 County Projects 31 5.6.3 Local Projects 34 5.6.4 Flood Insurance 36 5.6.5 Seawalls 37 5.6.6 Warning Systems and Evacuation 37 5.6.7 Zoning and Construction Regulations 38 5.6.8 Beach/Wetland Protection 38 5.7 Fiscal Impact 38 5.7.1 Funding 38 5.7.2 Flood Damage Expenses 39 5.7.3 Flood Management/Prevention Expenses 40 5.7.4 Financial Assistance 41 6.0 GOALS 42 7.0 POSSIBLE ACTIVITIES 43 8.0 RECOMMENDATION 45 8.1 Goal EH4— Flooding 45 8.2 Goal U3 — Storm Drainage 47 8.3 Goal EH5 —Tsunami 49 8.4 Goal ERC2 — Biological Resources 49 8.5 Goal EH2 -- Erosion 50 8.6 Goal LU 14— Open Space 50 8.7 Goal HCR1 — Historical Resources 51 8.8 Recommended Activities Matrix 52 9.0 IMPLEMENTATION 57 ii Res. No.2000-85 10.0 REFERENCES 58 11.0 GLOSSARY 59 iid Res. No.2000-85 EXHIBITS Exhibit No. Description Following Page 1 Vicinity Map 6 2 Ranges of Elevations in Huntington Beach 6 3 Near Surface Water 8 4 Geographic Features 8 5 Prado Dam Indunation Map 10 6 Regional Drainage System 11 7 Regional Drainage Map 11 8 Flood Control Channels and Pump Stations 11 9 Moderate Tsunami Run-Up Area 14 10 Newport-Inglewood Fault Zone 15 11 Subsidence Areas 15 12 Potentially Unstable Slope Areas 15 13 Liquefaction Potential 15 14 Methane Overlay Districts 15 15 Rainfall Data Chart 16 16 Local Flooding Map 20 17 Santa Ana River and Residual Floodplains 36 iv Res. No.2000-85 1.0 PURPOSE AND INTRODUCTION 1.1 PURPOSE The purpose of this document is to identify potential flood hazards and methods to reduce or mitigate flood damage. Adoption of the Flood Management Plan (Plan) will assist local, state, and federal flood mitigation and planning efforts. It will also ensure that flood insurance premium reductions continue to be available to Huntington Beach property owners and tenants. 1.2 INTRODUCTION 1.2.1 Floodplain Created In 1968 Congress created the National Flood Insurance Program (NFIP) in response to the rising cost of taxpayer disaster relief for flood victims and the increasing amount of damage caused by floods nationwide. This program was administered by the Federal Insurance Administration (FIA), a part of the Department of Housing and Urban Development. It led to the mapping of areas susceptible to 100-year flooding from known rivers, creeks, and other large bodies of water. The 100-year floodplain is also referred to as a special flood hazard area (SFHA). In 1971 the US Army Corps of Engineers delineated the limits of such a flooding in Huntington Beach. This map was based on the historical data and hydrological studies for areas within the Santa Ana River Floodplain that includes Huntington Beach. During President Carter's administration, the Federal Emergency Management Agency (FEMA) was created and FIA transferred to FEMA. In the early 1980s, the City petitioned FIA to reconsider the floodplain as delineated on the flood map for Huntington Beach. As a result, over 80 residential neighborhoods were removed from the floodplain by the issuance of multiple Letters of Map Amendment based on the actual site elevation and lowest floor elevation of the various structures in relation to the established base flood elevation. Since then the flood map has been revised several times based on other hydrological data and to reflect protective measures in place. It continues to depict over 50 percent of the city within the 100-year floodplain. 1.2.2 Flood Hazard Study During April 1974 the City of Huntington Beach Planning Department prepared a Flood Hazard Study as a background report for the City's combined Seismic- Safety Element of the General Plan. The intent of that report was to compile what was known at that time about the actual flood potential in the City, to identify existing control measures, to examine land use hazards, and to 1 Res. No.2000-85 investigate hazard abatement alternatives. Floodwater from the Santa Ana River was the only source of flooding considered in the report. Discussion of the control measures for the river and the flood control drainage systems that traversed the city was minimal. This information was incorporated into the General Plan that was adopted in 1976. A comprehensive General Plan update occurred in 1996. It includes the Hazards Element that addresses local hazards including tsunamis and flooding and identifies goals and policies to minimize these hazards. 1.2.3 National Flood Insurance Program Flood insurance is available to residents and property owners of communities that adopt and enforce floodplain management regulations required by FEMA. The City of Huntington Beach entered the flood program on February 16, 1983, with the adoption of the City's first floodplain development regulations. These regulations enforce the requirements of FEMA for development of property located within the SFHA. The basic objective of the floodplain regulations is to ensure new buildings will be protected from flood damage and that development will not aggravate existing flooding conditions. Much of the City lies within the SHFA. Huntington Beach is one of 19,000 communities nationwide participating in the National Flood Insurance Program. 1.2.4 Community Rating System In 1994, the City Council directed staff to apply for participation in the NFIP Community Rating System (CRS) which is a special program used by FEMA to allow reductions in flood insurance premiums. CRS contains many activities that exceed FEMA requirements for implementation to minimize flood damage. These include activities for public awareness as well as various methods and practices to protect property. Communities that can demonstrate that they implement activities that exceed the minimum requirements are awarded credit points. The credit points are then translated into classes (1-10, with 1 being the highest class). A minimum of 500 points is required for participation in the CRS program, which results in a class 9 rating. Each rating allows reduction in flood insurance premiums. The City received 1,112 points and initially a class 9 rating effective October 1995 with a Class 8 rating effective October 1, 1996. Class 8 communities are allowed a ten-percent reduction in flood insurance premiums. In 1999, prior to the five-year recertification of the CRS application, the City was notified that there are 15 repetitive loss properties in the City. As part of the CRS program, communities with ten or more properties that have received financial assistance from NFIP two or more times within a ten year period must prepare and adopt a floodplain management plan. Subsequently, the City submitted documentation supporting that protective measures had been implemented to reduce flood damage to some of the properties. FEMA confirmed this information and revised the repetitive loss properties to seven. Although no 2 Res. No.20W85 longer a mandatory requirement to.adopt a flood management plan, Planning staff believes that adoption of a flood management plan is beneficial to the community since many areas within the City are subjected repetitive flooding. This document will provide essential information and formulates a strategy to reduce flood damage in the future. At the conclusion of the five-year recertification, the City received 1,551 points and a Class 7 rating effective October 2000. Properties located in SFHA zones A (with no base flood elevation), AE, AO, AH, V, and VE will receive 15 percent reduction in flood insurance premiums. Properties located in other flood zones, i.e., X and A99, will continue to receive five-percent reduction for the rate applicable to these preferred risk flood zones. 1.2.5 City Council Direction At the November 1, 1999, City Council meeting, the City Council directed the Planning Director to prepare a Flood Management Plan for its adoption. This Plan will supplement the previously prepared documents that address flooding. During the FMP process, FEMA advised staff that the FMP did not need to comply with the mandatory completion time because eight of the 15 repetitive loss properties would benefit from recent improvements to County flood control channels. Staff believed that the FMP is important to the community and continued the process. 3 Res. No.2000-85 2.0 FLOOD MANAGEMENT PLAN COMMITTEE 2.1 COMMITTEE ESTABLISHED A Flood Management Plan Committee was created consisting of a representative each from the Departments of Planning, Building and Safety, Fire, Public Works -- Engineering, Public Works — Maintenance, and Administration — Public Information. Staff invited seven members of the community who live within areas subject to repetitive flooding to join the committee. 2.2 COMMITTEE MEMBERSHIP The Committee members are: Valerie Curry Resident Chris Gray Public Works Department— Maintenance Jim Hicks Resident Jack Kintz Resident Steve Krieger Public Works Department— Engineering Glorria Morrison Fire Department Khanh Nguyen Building and Safety Department Bob O'Donnell Resident Tom Pejovich Resident Susan Pierce Planning Department (Chairperson) John Tarvin Public Works Department— Maintenance Walt White Resident Cecil Wright Resident The following staff members provided assistance to the Committee: Dave Dominguez Community Services Department Joe Mangiamell Public Works Department- GIS 2.3 COMMITTEE MEETINGS The first meeting of the committee was held on November 4, 1999. At that meeting the committee determined that the focus of the Plan would be to address flooding on a citywide basis and to consider all sources of flooding. Biweekly meetings continued to define hazards, identify problems related to the hazards, set goals to reduce flood hazard damage, identify activities to attain the goals, and to draft an action plan. A representative from the County of Orange Flood Program met with the committee to discuss known problems with the County's flood control channels and mitigation efforts completed and proposed. Input was solicited from various agencies and adjacent cities. Past flood 4 Res. No.2000-85 damagelproblem information was requested from residents of repetitive loss properties. Results of the inquiries and agencies' input were incorporated into committee discussions and the Plan. 5 r 4E s MTIM Wpm ME k b� trnp pwm,� n ti e x� COUNT GoSol id2 : YF al.�W aWaU a:a.�.m - 777 Q rf drVE X$ 07 qw Mon, SaL Y my umrr If INNUM-SaAam Mall P EXHIBIT angel of Elevation in the 9 City Of Huntington Beach JN I AA Elevation Ranges f9amc�Gt�� :15� S v'w �3w 25'Eo 0 A, 5:to loft r w SY, xt w 10 it Sty to 75 k ZOA3 3.997 o E to 5 Etna Cx Y: ii cm 9u.5i3; i ,Magjot MwF33§ 101,L I 006q. 4.814 % ,_ so y 1,493 EXHIBIT Res. No.2000-85 3.0 COMMUNITY DESCRIPTION Huntington Beach, California, is located at the northwestern edge of Orange County. It is bordered by Westminster to the north, Fountain Valley to the northeast, the Pacific Ocean to the west and southwest, Seal Beach to the northwest, and the Santa Ana River to the east. Costa Mesa and Newport Beach lie east of the Santa Ana River. The boundaries of the city are irregularly shaped with a base of approximately nine miles along the coastline. The area within the city boundary is 27.7 square miles. (See Exhibit 1.) Population estimates reveal approximately 199,326 persons reside in Huntington Beach. Huntington Beach has a mean annual rainfall of 12 inches, and a mean monthly temperature of approximately 62°F. The topography, which is primarily flat, varies from below sea level to over 100 feet above sea level. There are two mesa areas that disrupt the steady slope of the land toward the ocean. Exhibit 2 depicts elevations within the City. A considerable portion of the community is less than 10 feet above sea level and properties located in the eastern portion are lower than the Santa Ana River. Several areas of the city are also lower than the top of the adjacent County flood control channel. Three major highways traverse the City to provide both regional and inter- regional access. Pacific Coast Highway (State Highway 1) parallels the shore and provides regional access from Newport Beach to Seal Beach. State Highway 39 (Beach Boulevard) runs in a north-south direction near the center of the city. It provides access from Orange and Los Angeles Counties to the coast. Interstate 405 (San Diego Freeway) at the northern edge of the city provides regional access to coastal cities in both Orange and Los Angeles Counties. 6 Res. No.2000-85 4.0 HAZARDS Geologic and seismic hazards have been identified in the General Plan. These hazards include shallow water depth, faults, liquefaction, tsunami and seiche, subsidence, methane, and flooding. Flooding can be the result of a variety of causes or hazards. The Committee identified the following hazards for inclusion in the Flood Management Plan: Bluff erosion Pump stations Dam failure Reservoirs Earthquake faults Santa Ana River Flood control channels Subsidence Heavy rain Tornados High ground water table Tropical storms High surf Tsunami High tides Unstable slopes Liquefaction Water main breaks Methane These hazards are grouped into five general categories for discussion. They are: ♦ Weather related flooding from heavy rains, tropical storms, and tornados ♦ Flood control (Santa Ana River, dam failure, flood control channels, pump stations) ♦ Pacific Ocean activity including high surf, high tide, tsunami, beachlbluff erosion ♦ Accidents such as reservoir leaks and water main breaks ♦ Geologic hazards including earthquake, subsidence, liquefaction, methane, unstable slopes 4.1 WEATHER RELATED FLOODING Huntington Beach weather conditions are consistent with coastal southern California. During the winter months an average of 12 inches of rainfall occurs in this semi-arid region. Summer months are warm and dry. A threat of severe winter storms is greatest during December to March. The threat from tropical storms is greatest August through October as a result of hurricanes from Mexico. The southwest facing beach of Huntington Beach can cause surf and wave impact from both winter and summer storms. Heavy rains combined with high tide and rough surf create an increased potential for flooding. High tides often prevent the Santa Ana River flow into the ocean and result in flooding in the south end of the city. 7 Res. No.2000-85 4.1.1 Tropical Storms The City has experienced tropical storms related to an El Nino condition. An El Nino is an oceanic and atmospheric phenomenon in the Pacific Ocean that causes climatic disturbances. The disturbances occur when the ocean temperatures in the southeastern portion of the Pacific are unusually high. Air pressure is very low over the warm water. This causes the moist air to rise, causing clouds and heavy rainfall. As the trade winds blow from east to west, the unusually warm weather and tropical rain storms hit southern California including Huntington Beach. 4.1.2 Heavy Rain Several areas in the City have repeatedly experienced local flooding due to heavy rain. Many of these areas are adjacent to pump stations and/or flood control channels that are not capable of containing the floodwaters. Several areas are low lying areas where proper drainage is not provided. And, in some areas, there are no catch basins to direct water flow to a storm drainage system. Because the city is relatively flat, there is not enough decline in elevation to allow water flow by gravity to the ocean and pumps must be used or provided to insure timely drainage. During periods of heavy rains, water fills the storm drainage system to capacity. Nearby pump stations are unable to pump the accumulated rainwater.into the substandard flood control channels. Drainage problems occur as the excess water begins to fill streets and accumulates on adjacent properties. 4.1.3 High Water Table/Wetlands A large portion of the southeastern area of the city has a high water table. (See Exhibit 6.) When the city experiences heavy rains, the land is incapable of absorbing any additional water and flooding may occur. Some of the high water table areas have been classified as wetlands. Wetlands may be found on the inland side of Pacific Coast Highway between the Santa Ana River and Beach Boulevard and in the Bolsa Chica area inland of Pacific Coast Highway between Warner Avenue and Seapoint Street. (See Exhibit 4.) The Talbert.Marsh wetland and the Bolsa Chica receive local drainage waters and tidal influx from the Pacific Ocean. These wetlands provide a holding area for localized flooding and a habitat for wildlife. 4.1.4 Tornados A tornado is a violent whirling wind accompanied by a funnel-shaped cloud extending down from a cumulonimbus cloud. The vortex may be several hundred yards wide whirling destructively at speeds up to 300 miles per hour. The narrowest portion is where the funnel touches the ground. The funnel is 8 i ai SEAL AHUlm Mill ME \ Ek \ \ HM WNT LLV \•fir 3 r/ ONE. r i/r C, r S `•\,..:, v 1� f \ +,�a Ifr i/r i� 3 IA � ppp . Low nd ,MM \ \ 'h agg,,,,,,B • rlr Grr CWA <: I O-ao Feet ! 0 FW �s Fee Y „ter \�\�\ � ,\ \ jai \ <3 Feed NEAR SURFACE WATER EXHIBITLIJ 3, 7 f. 9I e aesaw �� ------------ 05 WSW uj is 4� 1wry.1oil f Mass f' Res. No. 2000-85 visible by the dust it accumulates and the condensation of water in the center. Tornados develop in low-pressure areas of high winds and usually spin counterclockwise. Damage occurs as the tornado funnel moves over and touches land. Structures may explode when they are not sufficiently ventilated to adjust rapidly to the change in air pressure. Rain and hail often accompany tornados. Although tornados are rare in southern California, three tornados have damaged properties in the City. 4.2 FLOOD CONTROL 4.2.1 Santa Ana River Huntington Beach lies within the Santa Ana River floodplain. The Santa Ana River begins near the Mt. San Gorgonio summit in the San Bernardino Mountains at an elevation of over 8,000 feet. Its course drains over 90 miles through both the San Bernardino and Santa Ana ranges; 27 miles of the river course flows through Orange County to the Pacific Ocean. The Santa Ana River drainage basin covers 2,450 square miles and is the largest basin in southern California. Many hundreds of years ago the Santa Ana River flowed through the area now known as the Bolsa Chica wetlands. Later it abandoned its course and established a new course in the Santa Ana Gap. Alterations to the river's path created the cliffs of Upper Newport Bay and deposited sands that formed the Newport-Balboa Peninsula. The Santa Ana River is the largest river in Southern California and the flow from the Prado Dam reservoir through Orange County was perennial. Since construction of the Prado Dam in Riverside County, increasing upstream usage, and development in adjacent counties, the river is very low most of the year. Most of the water is used for irrigation and recharging the underground water basin. Little continues to flow to the ocean. With the completion of the Prado Dam and channelization of the river, water flow was contained in 1940. At that time most of the river followed its natural course while the remaining portion including that within the City was a levee, sand bottom channel. 4.2.2 Dam Failure There are two flood control dams that control flood flow of the Santa Ana River. The Seven Oaks Dam is located on the river in the upper Santa Canyon about eight miles northeast of the City of Redlands, in San Bernardino County. This dam was completed in 1999. The Prado Dam is about 40 miles downstream of the Seven Oaks Dam. Approximately 47 billion gallons (145,600 acre-feet) of water can be stored in the Seven Oaks reservoir and 61 billion gallons (187,600 acre-feet) in the Prado reservoir. During a flood, the Seven Oaks Dam will store water destined for the Prado Dam for as long as the reservoir at Prado Dam is rising. When the water surface of 9 Res 200*0.tS Prado Dam reservoir is leis than the buffer pool, eater conservation releases are rude. Water eo'n ery tion releases are. en made In coordination with the ein r , e County Water'District basQd on the capacity of the groundwater recharge facilities and agreements with ether agencies. Flood con.,trol releases oecro€r when the, water surface in the reservoir exceeds the buffer pool. l elaases are increased to match inflow from upstream � z000 cubic feet per second), The, objective of the flood control ;operation is to drain the rese r m r- pools as quickly, as possible without exceeding the capacity of the channel downstream, When the water surface elevation in the'Prado Dam reservoir exceeds 543 feet, uncontrolled releases from the spi'lway',occur. In the event of Prado.Darn faiiuro floodwaters would florin through the, Santa Ana Canyon on Its way to the, Pacific Ooean. The food would range from bout 3_Or-1 feet wide.in the canyon to over 15 idles wide downstream at the Santa>Ana. Freeway (interstate ), The.flooding woluld impact over One million people and 110,000 acres. Within 8-10 hours, tha€ntersection of each cede Yard and Edinger Avenue would experience severe flooding. The peas.'elevation would be 32 ft. with -ft. average age over the river's'bank depth'. The, greatest flooding -would occvr in the area between the, Bola Chica Mesa and the Newport Beach Mesa where flood depths can vary from one to rime feet,'; (See Exhibit 5) ♦ ~��v atRMa.3'v,YV 7.r2.2 °v v..- 2 `. >< � "'°i♦�,.`7: "'£ e7rt vY,ab @�:.ai�': ves hv�♦�y � .r�'mc\�zvt �c.�i�A.z.�i:: si;<caz.aft�tzaxY v,�?:::.,♦��.. "yet' ` v�v�3•P`�e. F+e-.. a ♦ aN7.hu>� 10 R f r Ar €fir?� 5 €�13 °ram V 3,r I PC L AT fit?< xA F � a t xx i hN F � ARtA?c o'11,45 ORMATIO.N '.OM- r i li 2 BRAVO DAM U 51-92A v'f Rt5t K AANIVAf_ HOLD AVG. OVER,BANK f-tT PRADO DAB INUNDATION . MAC WITHIN THE CITE U TINGTON 8'CUT OF NVm,TnlfqTow,,aRA-cR -------------------- ' c EXHIBIT 5 e' E, Res. No.2000-85 4.2.3 Flood Control Channels A large amount of water from other parts of Orange County flow through Huntington Beach on the way to the ocean. These regional water flows are carried through flood control channels owned and operated by the County of Orange. In addition to these channels, the City of Huntington Beach maintains flood control channels to drain local floodwaters. (See Exhibits 6, 7, 8, and 16.) 4.2.3.1 County Channels The existing County channels were constructed in the early 1960s to meet 65 percent of the 25-year rainfall (flood) level, the design criterion at that time. These channels were constructed with a restrictive bottom, which reduces the amount of water that could be carried. The restrictive bottoms allow the County to slow the runoff water flow rate while still allowing the system to remove runoff water. At that time the County believed that the restrictive design could be removed or the channel bottom smoothed in the future to increase the efficiency of the channel capacity. Today's design standard is for 100 percent of the 100-year flood. (A 100-year flood is a flood event that has a one percent chance of being equaled or exceed in any year.) Bartlett Park, located north of Adams Avenue and east of Beach Boulevard, is an emergency retention basin. The County has an easement on this property to retain water that will eventually be pumped by the County's pump station, that is located on the south side of Adams Avenue, downstream into the Huntington Beach (1301) channel and eventually into the Pacific Ocean. The basin was constructed approximately ten years ago. 4.2.3.2 City Channels The City of Huntington Beach maintains four storm drain channels throughout the city. These channels were designed to accommodate up to 60 percent of a 25-- year flood event. Ground level channels exacerbate flooding because the amount of water that can be pumped into these channels is less than a channel constructed below grade. Localized flooding then occurs because the pump stations are unable to pump additional water into the channel without the . possibility of overflow onto adjacent properties. 11 404-85 REGIONAL DRAINAGE SYSTEM Orange County Flood Control District Channels that pass through Huntington Beach Balsa Chica Channel (CO2)with tributaries Anaheim-Barber City Channel (CO3) &' Westminster Channel (C04) 1. Drains portions of Huntington Beach, Westminster, Los Alamitos, Cypress, Garden Grove, Stanton and Anaheim. 2. Drainage passes through Anaheim Bay and the Seal Beach National Wildlife Refuge before emptying into the Pacific Ocean at Seal Beach. East Garden Grove-Wintersburg Channel (C05)with tributary Ocean View Channel (C06) 1. Drains portions of Huntington Beach, Westminister,Fountain Valley, Santa Ana and Garden Grove. 2. Drainage passes through the Bolsa Chica Biological Reserve before entering Huntington Harbor,Anaheim Bay and the Seal Beach National Wildlife Refuge before emptying into the Pacific Ocean at Seal Beach. Sunset Channel (C07) 1. Drains a small portion of west Huntington Beach. 2. _Drainage passes through Huntington Harbor, Anaheim_ Bay and the Seal Beach National Wildlife Refuge before emptying into the Pacific Ocean at Seal Beach. Talbert Channel(D02)with tributaries Huntington Beach Channel(D01)&Fountain Valley Channel(D05) 1. Drains portions of south Huntington Beach and Fountain Valley. 2. Drainage passes through the Talbert Marsh before emptying into the Pacific Ocean just west of the Santa Ana River. EXHIBIT S (map on Exhibit 7) � 4 €na; ` 'a s� � .o i 'bb ..;�r J.r •'�1 ��FS� � 4? � � e33 /t r s'T',�'�^+�';,'r ;r �,. . fit, ` %�'., 5 '`.• >,,K� , F' ^E'y i:, 4 vo. 7. .1;E S' � L��y..' 9+ :• � p:" � 3 a e^h 'f ',,tl�S� 4 � 'St3 �3 Yw-°S� `w' Elf t4/ 1,�� r t ✓S?' g s, r ^s ".�} � �+ h ,- r'r"rL Y �<` fit\ ,, fti.�, 1_ � Y• "� y.t r r".�> '� s,Y .:"Sk � �.+`< .x. Y.wt'`at•w'r.,5 t ? � +�> .� ♦ � .yk3 � � t r * �,;. f f15 Q} � 4-' t � � ... y. �S 5• L � t i i r r < f s i Flood.Control Chwnefs and �? stom n Drain Pump long it I} irl yt f MAW i t, 1 E ATUMA t Y., t#i�La,A.h4C.A � BYitX44StRF'GLi^o :. � c 3L� P.LMIL11134 WELDS Y :tt4 YPCtCFCi5mN € 2 Was MO + €La WS MAP 3I, xm 1m tte>: is Skc s i �cr,one cArnrxi,��>si� a� : 3E D�1�mbtt€m nxatxxai:�iRY;S '� E )c3.�'3.�.xta S�w.aafavt S�fa'�€�vya4' fGdthl;at£kJnf'a f7oAC'�m icolia�"Z We + - L aA:. 1'V^ A¢'eaia�� tii�asio*m?r+ : �v gig gyp;IT 'i:8 8 `"ii'a9.3ava.teFssae�P�otadeLtax»Ya»lyti>vet5,etafb T' s � n earthen>.flood control channel 4.2.4 Pump Stations' There are pump stations A+ithin the City that are an important.t part..of the drainage system. They are. € sed to pump vvate€-flovi from:low ly€ q public,and d private property to higher channel elevations for eventual few to the.ocean, Pump stations mayalso p�,lmp water into flood central channels from storm drains that do not flow directly to the ocean, One of the pump stations is owned and operated by the County of Orange- it has six pumps. The!rerna ninstations are owned and loperated by the Huntington Beach Publio Works e art€ ent. Depending on the size. off the tributaN, area.a station€ eon'have tw.0 to ei hA pumps. Currently there are 47 pumps in the 15 city-owned stations.. Every sta ler is-setup differently € their functionality remains' he same. The number of Operating::,PUM 11 p in a station is correlated t tie hey ht !the water ter the station. Once a r�de�erra�ir€ d ei��atia leas��e€� reached thefirst' pump is activated. If the eater level continue tq rise, ditior€ai peps- activated. Each pump operates in €.€a€sr n trying to keep tha Nvater level at the predetermined elevation. The pumps continue:to ru unt€1 the water level recedes, Once this happens the p €glps smut down in. the opp site order than they start, Pump stat€on locations ,are shown on Ex €b€ts 8 and 16, Prey r€tl ail of the it 's pump stations are operating within gear current design capacities and are considered deficient b urrent standards,' 1 R . Nas 2000-85 7 IP c yn d... t w�'an:�\K� J �-.-.T+^1r.4ti'-mryu\�-1+•.VT1A�1C4+Y..i: . Shields Pump Stet€cry The County e# Orar€ e has informed. the!City that instellat-On et additional pumps or pump stations will not improve the drainage problems that frequently exist during periods of heavy rains until its channels are lrr€prcved. The,main problem lies with the incapacity of the clam€el systern to carry any add.,ifional waterthat- rnaybepurnped. Capacity in a channel is dependent on its height and width and on the design of the channel(s) downstream, When a channel does not ompl,£with tie minimtim FEMA I00-year capacity, 'my additional water pumped) into e channel may breach the channel banks, cause channel tazlure, andlar create flooding problems for'adjacent pro- edi �. 4.3 1 �&,' l lC OCEAN ACTIVITY 4.3,E High Tides Tides are the periodic r1se and fMl of all ocean watersle.sulting from the grey.itab n l attraction of the.,moon end the sun upo the water and upon the earth. Because the ccr# s muc >Ooser to the earth than the son., it i the principal cause of tides. The location of the moon over the earth.creates a. powerful pull on the water, which then rises Abo-ve its norrnallevei, Hipp end low'. waters alternate in. e continuous cycle with two high Waters and two low water every lunar day, The average lunar day is.244 hours 50 n-vin €ter and 28 seconds. Two successive high or low eaters are generally the a e height. 3 Res. No.2000-85 4.3.2 High Surf High surf occurs when wind from storms at sea forces the water level and wave action toward the shore. Typical surf in Huntington Beach is two to four feet, and waves up to 25 feet have occurred during heavy storms. 4.3.3 Beach/bluff erosion Beach and bluff erosion is a result of the high tides and high surf. Continual erosion could impact highway and beach access and possible bluff failure. 4.3.4 Tsunami A tsunami is an oceanographic event with gigantic waves that strike the surrounding shore with tremendous force. Underground earthquakes, midocean volcanic eruptions, and serious atmospheric disturbances cause the waves. A tsunami threat to the City of Huntington Beach is considered to be low to moderate. Since the city has southwest facing beaches, they are vulnerable to south and west tidal surges or tsunamis. Predicted wave heights vary from 4.0 ft. to 9.2 ft. for 100-year occurrences and from 6.8 ft. to 16.0 ft. for 500-year occurrences. Areas subject to tsunami runup are depicted on Exhibit 9. 4.4 ACCIDENTS 4.4.1 Reservoirs A total of 49.5 million gallons of water can be stored in the city. There are two reservoirs located in the city and a new one under construction. The Overmeyer Reservoir consists of two storage areas, 21.5 million gallons and 3 million gallons. This reservoir is located at the water warehouse/maintenance facility at Huntington Street and Garfield Avenue. A second water reservoir, Peck Reservoir, is located at Springdale Street and Skylab Road. This reservoir contains 16 million gallons of water. These reservoirs are underground and no flooding could occur if the reservoirs fail; no properties would be affected. A new reservoir, Edwards Hill, which is under construction, is located west of Edwards Street, north of Garfield. This reservoir is mostly underground, and will have a 25 million gallon capacity. Any water leakage would drain westerly into the Bolsa Chica wetlands. 4.4.2 Water main/fire hydrant breaks Accidents to water mains or fire hydrants may cause temporary localized flooding. Water main damage could occur anywhere within the city because of age, pipe corrosion or sudden changes in pressures. Fire Department and 14 � u L Vim d NFr 5 W - y,oo- ias C NKa awl FT fi�l1'y�,�,d'4r t (s a f "Sys,x"a+r f �rC� {sis ��Lf��ni�t �ff f`�n,��r•, t 7 �04 +t tr 'T �y°t.✓�s.q�'�' <S.t r,�Crs'af' s',C Lr;Fr•• IRA OWN, .- 9»,„ra.� 0.S f k' f •.7'�66 rCi'..''t"4��.3' �S��:� �„ L°J� M'nv,. os q sf S t{ syf t S ro tP. tff v rI;41 kt r 5" i f n h 5 itt �TL�vSy a is �b sits SCS �'" SrS'^ItIN.VI eP/ ° �� x zit S S j ,k.� 'r �s _ �pS'3 -•ao-. f^. ti NO @a y r'S fil- �y l ^fir• Res. No.2000-85 Public Works maintenance personnel routinely inspect these water sources to ensure that the facilities are in good working order. Accident related damage would be short term flooding. 4.5 OTHER GEOLOGIC HAZARDS Some geologic hazards may create or be affected by flooding. These include earthquake faults, subsidence, and unstable slopes. A series of earthquake faults traverse the city. An earthquake could rupture water lines, damage bridges and flood control channels, or create crevices that would allow water accumulation. Earthquake tremors can cause soils with liquefaction potential to loose strength and liquefy. This may result in ground settlement, which sometimes causes buildings to sink or tip over, or shallow landslide conditions. Oil, water, and gas extraction in the city has created areas where subsidence may occur. This extraction reduces the force on the ground surface allowing land and/or structures to collapse and become more tightly packed. Sea level rise affects coastal flooding as land subsidence occurs. When the two are combined there is threat of serious future flood damage to the coastal areas. Unstable slopes may fail during heavy rains and may create mudflows. These hazards plus methane, which is found in areas where oil extraction has occurred, are shown on Exhibits 10 - 14 and are addressed in the Hazard Element of the General Plana Methane does not create or impact flood damage but is a known hazard to the community. It is included for information only. 15 LAD 7A,WE ta Aw, IV�M i w,w SC• 4 �,ys 99 /7s6,�3'0;7fiA�e� MMA to If 0 it _ Elt1: �1� � � '�" Q �b_,y.�� •�r':y,E4 gf1.�14f�y 9�,�y.✓`kfif.+�,��F'.. �,L�+�S' SA � ,� 'tS9' NA >Rr `f^r 811 &pa M� w r h S• �v 0 j car. S,sY77 j' 4 LV i ,i 4-Y]�f{;.S ,SF',.v�.R 15` 4A ;Y o b fit • �M / y a #amf # WO aYHIFb'NYI "�¢¢ %b55f5' b+bvN Yry'f91+Y I % 1.0 o f WN 07 f }s5�, ,g}., t ' � a L_!.(� bJ.s � �` � � f�➢��' f 3�"j {f,6� ;•'J`}„"�R �� ,p-r�� y x� ___—�q.. ...w.a'M<�.« G k} I'{yy� 63K ¢ m a G<�sr :,� 4 � CA YIN �t x 4 ; sR ysB < {� � fy !Y ty" y4�4Ica�'�`a f•sai;tt�i .:�� 6 1e�� 'L'fJ'"ii p2s TP � 5 � lip ir h97A6' Rt r�no°w a g i�.M.,�.�^^^�x mum WON iF"`s"4q,V,,.............M,�....,,..I � �� ... i- ` ------------ Fesi UJ UJ WESTMINSTER SEAL F Ell �#' �&��•a r/��i/\`\\i.\\\\. ✓ tom;\��\ '� i 10 VAUEY kois rril r t" Ilk Syr v4t,�}\ ii frd'• ;C \\r\\? `✓cY \ t✓✓r +' rr a //f lrF/�%' tika` Y\ �.\.;�k�a `\ 4�✓F/J x``, "^ � 4C Y r �fU if h { p\ \X4 +•t `�' /r\\•\•�•1\A•r{�\� � '. : A -X r\C�'r�, l/i r•i... '>-.._ •„a4�~ pg �> >/r a w ��\\ �h� •\4\\4 3 ci.Gi�i�l,{/i�lrr/'ir� rnti. \��✓.ff�f �\� z u:�J3'K"�5 �s� Nfi 1,1,E IRV r\�\\\a\,\t \•4 r\ ` `� tagod low rh �Jtgj-,to Very sigh poteinft w%r \ s LIQUEFACTION POTENTIAL 9,n-j ;En EXHIBIT .OfTy 01 AL PLAN Res. No.2000-85 5.0 HAZARD RELATED IMPACTS 5.1. HEAVY RAINfTROPICAL STORMS As previously mentioned the mean average rainfall for Huntington Beach is 12 inches. Rainfall records measured at the Meadowlark Golf Course area for the past 20 fiscal years are shown on Exhibit 15. Periods of heavy rainfall over 20 inches are: 1977/1978 26 inches 1982/1983 22.5 inches 1992/1993 22.10 inches 1994/1995 21.8 inches 1997/1998 27.5 inches A brief summary of flooding events reported in local newspapers follows: 9 Following a heat wave in 1939 with record high temperature of 119 degrees on September 21, a tropical rainstorm with heavy winds walloped the coast, drowning dozens of people, sinking boats, and flooding homes. A 300-foot section of the Huntington Beach pier was tam out. ➢ During the February 1969 storm, Huntington Beach storm drains and flood control channels were unable to handle the extreme water flow and nearly all of the lowlands were covered with water. ➢ A series of storms in 11983 lashed Orange County's coast causing heavy damage to the Huntington Beach pier and flooding many homes. As a result, more than 900 homes were inundated with water. Damage was $25 million. (The City's Emergency Operations Center[EOC] was activated for three days.) 16 8 'P x. y is<:i:' ......::><::>::>::: :vi::<i:;�v:ti':.:`':,tint';:=,;:;_i:,'.:::".,.::: .....................::::::..........................:........ ......::.....:..:............ .\., ;:.:Nf iy:;.;t M r'• %�.;... ci:«;i;i..':i;_ ;t;t::::: :�+}tcw✓:% t: yi;: ::: :>- i.. .t.i....t...t...t...: �� ll�..�lll�l ..........:.....:.:�...:::.:.�:..:::::. .....................................:. 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South el Adams ;avenue and North New Britain - 1983 17 8 \:)' ,\s 4\ \ 4 v` is \\. 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Jc ..3R :: :,vi? :�:0:.::35'%pz:?:d},}a?C;v::.y»♦.cy:::.,�:::��::�?::?y:':::.:k .:,.�,:; ..va:i`i�:�'? \ ,:?aea7."iSt:':x;:.�\.:?:��ca•- ?: .... ..:c....... ..\... `�':.�� ;.v:`:•,"�\ .\\.;.\. �i�aA\i$;:SS:S:c\''�?:�>�:�::K�:�:\,.�.,��:?.:.�:>:;•:'.x.:;.;,;::�;�;.;+ '.;•.. .\ 3<i33i�i�? a:vX?n?ii^i}\\��???::i�ii:�iii:?v:.�?i?::�i::, ::�i:�iii5 ...:?v:•�.:.:. ,. �a v?\-\\�: a,. \ O ..}........ \♦�<i :;;� `:�:::� ::°vvti? :?•;:v::;::;ti;:.-:.��;.;; :: .j}e- �v`w@:\a ? �i;ai'•, v. •• ,.� -vim,`'`',`\��`v:`i'\\ Af d * A A �6 A r.� Res. No.2000-85 events that related to this storm included flooded streets, high surf, raging storm drains, and significant erosion at the city beach. The high surf undermined restroom buildings at the city beach. (City's Emergency Operation Center [EOC] was activated.) ➢ EOC was activated twice during the first week of February 1998 as a result of continuing storms with increased intensity due to an El Nino condition. The intensity of rain caused closure of numerous streets throughout the City. A sudden downpour, preceded by constant rainfall caused a flash flood down Brookhurst Street, between Garfield and Adams Avenues. The water entered the Del Mar Mobilehome Park, raising the water levels in parts of the park up to 2-3 feet within 30 minutes. Twenty-five residents were evacuated to the park's recreation room and remained there until Fire and Public Works crews managed to pump and drain out most of the water. Approximately 500 sandbags were used to barricade the park's entry. None of the mobilehomes sustained flood damage. ➢ A two mile stretch of Pacific Coast Highway was closed at Bolsa Chica State Beach due to more than 2-inches of rain and 10-foot high waves during February 2000. Power outages were experienced in several areas of the City. 5.1.1 Repetitive Flooding Areas Areas that have experienced local flooding within the past 20 years are depicted in Exhibit 16. A description of flooding problems in these areas is identified in the following paragraphs. Approximate water depths are measured from the flowline of adjacent streets. Each of the areas has common problems: inadequate drainage, properties lower than the nearby flood control channel, or lower than the nearest arterial street. During normal rains as well as heavy rains, many of the residential neighborhoods in the City experience flooding. This is a result of a common development design in the 1960-1970s that created neighborhoods below the level of the adjacent arterial. In these areas it is common to experience curb-to-curb flooding. Many properties that have been graded in a manner that allows water flow toward the house/structure. Flooding occurs where tree roots have raised sidewalks and cracked curbs and gutters prevent natural drainage to the storm drain. 20 IV ; a (Mt AVE26 aM lL ,�� 30 NOT TO SCALE — < - 1 € ° ' s LEGEND ; # ' -BOUNDARY CIS PUMP TAT] N COUNTY CHANNELS i €AID€ AREAS� OF � LOCAL FLOODING APPROXIMATE LOCATION . � OF CRITICAL. FLOOD AREA CIS F TN. Q, WORKS DEPARTMENT Of Puou:cl LOCALFLOODINGMAP 1,N L � I � Ises EXHIBIT - w ------------ ��\\�.�t�ilk�C�\ ♦ , ` `y.,.%t it h \ L . Area 1 - Heavy rain combined with extrem e. ,;high tides '6.8 fb t or greater) impair the water t aa,n properly facim the area mar Saybrook Lane soot of Edinger Avenue,, Water depth i es imated'to be:about one fiaot, 5.1.1 ,area 2 The area in the v i€pity of Alhambra Drive, Glencoe Avenue, Silver Lane and MacDonald Avenue (northwest of Hall'Avenue are BeachREou evard is defrc,ent in drainage facilities such as e€rrt� , gutters, and a storm drain system. Depth of water is estimated to be about the feet:during periods of heavy rain. 5.1.1.3 Area 3 - >l lei.$area north of War ner Aveaue,'west f S r€n9d e Street is s1tuated lower than the adjacent C-05 (East Garden Gr ?tile - Wintersbue, Channel):aid is considered to be in a levee condition. The nei hbor oqd experiences ofi=s to ens fre€r Me dowl rig Golf Coum,e d rl€ig P.*er€eels cif eav rain. The deficient storm drain system cannot hat dl fleets every fro a moderate rain. Could with thisdrainage problem n s ptrsid ce.that the ei r d 15aexperienced, (l e water hay been as deep assthr°e met d rir :ri ds f fseev< €ai€ e In ' , water� ithin thl e channel breached the banks.s. flooding tie property to the east of the flood control channel. 21 e's, £ fti ZZ yp1 \ Lark, t.ee area . a 1A Area 4—A deficient storm drain system results, ire two to three feet of flooding at Rogers Drive and Remington Lane, so theeet of Warner.Avenue rid Graham Street duri periods of heavy rein, . A-5 Area, 5 - One to,hv feet of flood n results ddrthg enod of heed rain due to a € storm elnter Heil ' del Street area: 511�6 Area 6- A deficient storm drain system results in.one to h1vo feet of flooding,in.the area of Shields Drive (north of Werner Avenue between Springdale and Edwards Streets)during periods of heavy rain. 51A.7 Area 7—The defickant flood control channel North of Warner Avenue at oldenwest'Street has overflowed durin periods of ee% reln '. causing two to three feet of flooding, The deficient storm dril in,Goldenwest Street € of`v rner er eel cause-s flooding problems .1 A area 8-Heavy "air. and.deficient storm drain ystern result €n:three to four feet of flooding in the area df Corsican Drive a nd B rdoo Lane',(weat'of Gotha rd Street and north of Wamer venue). This neighborhood is: hunted lower tt�er thesurroundl free, and r ldered to be i e levee condition since,it is located'adjacent to the C05 (East Garden 'Grove - intlerebur Channel). 5JA'9 Area 9 - Deficient:storm.drain system results in one to two feet of flooding In the TalbertAvenue and Sprin dale treat ire !durin periods of heavy rein.' 22 5.g 11.0 Area 10 -- Properties in the area of Michael l rive an effe south of SlaterAvenue are low lyin re-as, T'he d, cierst stermdrain System, results tu�de free et of tlecxd!1� ring er1�d� of r� �era�e reim This area 1902, 1 9 , 19- , 19195, 1 7, and 1 99 , The 19 3' eve t was so sever.e'that the National Guard patrolled the neighborhood aster the residents were evacuated. 5 l,1.1 t Area I I w Properties located in. the Newman Avenue and Forest, Lane area south of Area 10 have use to three feet of floodingduring Periods of heavy rain>due to t e, defident bra€na e,i cyst rn, Drainage from the ernewervr hi-ch is looted scout4 of thi� nei hborhoo , "lows kectly into the low yin properties located On Newman Avenue. This algu ce cunt s flood€ impacts' in Area 1 W ♦a M \ :M, �\a ♦ M1 r S S �,\♦��.♦ \\\\ter e x♦\\5..\��•t ------------------ IN a as Goad Shepherd Cemetery viewed from Newman'Avenue w 1994 3 �- w. .°v{ \ ' �a��\ .:ice �` !•+�k�\ \ -w vaLacuYa �.. Water fr r l e d l e herd emeater f owrig �ertl��rlx�� across'. Newman Avenue . Area - 3i nd'Seve, teer�tl� Streets e ver€en �n€ �b�� flooding during. Periods of heed :ire as result of the defidient stor dr €n ss stem mciudi€ig the lack of stoma drains. . 13 area 13— Mein and'Fourteenth.Streets experience.one foot of flooding d ri periods of hea r l re €l t ie t Store drain S tern. .l.3.14 Are,a 14 Properties located between Seve th and Twenty-second tr et south: r r� e r ver e ertence one t by Beet of flood €� dorir� periods of heavy rain: asr.esultlbf the deficient tom drain system. . P a Ares '— obile o e!Park west of Beech Boulevard:and: north'. f Adwita>Aven e his olie to wo feet of flooding d rlr er d �;r r� due to deficient storm drain systems including the lack of Storm, drains. . Area 16''— A iIarge efem east of e C -Oull}4 rd'and.south of Adams Avenue e b' ser sl imp e�ted d� �r� tine �� rainy se on � rains and channel failure resulted inthree to four feet of water- 24 x t + v IndianapolisAV;--nu:e and b each Boulevard area '� 198 tme-UHarnilton: in a facilities curbs,'gutte € r drain stem.' € Of water is brnatdd to be one to three duriinig periods of heave rain. 5"11.18 Area 1 — Portions of the Condominium corm lex located at the northwest corer of Atl nt�Ave and €Magnolia Street x 'rI s up to one ar £ ofwteuri � � � rindue to a dej;i it � rn d Cr � r e rain system, Area 1 - In,the area south of Atianta,even any 1 a n 1jM Str-eak= the earthen Rood control channel failed and Ca Used up to sly fe6t al'flood€rya, +1 1, Area —Heavy rain and a deficient storm drain SYstem r ult�in bNO feet of flooding in the area, Of York-tOw: Avenue/ ��€sh�rd Street. �� , eater breached the barks of the flood'control channel, Area 21 Mobil ho€ e parrs located Ir€ the'Garfiteld v r" € 11 r l t r t try t r re bst r##l6ll° i per^th t d c € t '. Control channel, A deficient storm drain Sys-tem r'esuR n four to sly feet of flooding in the aresa during periods of heavy ram.. In, 1983 and 1995,water breached:the banks.of the ftood.control channel. 5.�1.1, Area 2 - Pr'dpertie located south of act �€� verrue'and east of Br:?okht.€apt Street, erg., Meredith Gardens, drain into theSanta.An River. T el 25 Res. No. 2000-85 deficient storm drain system does not allow proper drainage into the Santa Ana River during periods of moderate rain. During the heavy rains such as 1983, 1995, 1997, and 1998, the area was flooded with three to four feet of water. 5.1.1.23 Area 23 — Heavy rain and a deficient storm drain system result in one to two feet of flooding for southbound traffic on Bolsa Chica Street near Bolsa Avenue. 5.1.1.24 Area 24 -- Heavy rains and a deficient storm drain system cause floodwaters up to two feet deep in the vicinity of Newland Street and Edinger Avenue. Three county flood control channels are in the immediate area. 5.1.1.25 Area 25—A deficient storm drain system results in one to two feet of flooding in the area of Brookhurst and Bushard Streets during periods of heavy rain. 5.1.1.26 Area 26 — Heavy rain accompanied with high tides (6.4 feet or greater) impair drainage in the Huntington Harbour area. Depth of water is estimated to be about one foot higher than the top of curb. 5.1.1.27 Area 27 — Heavy rain and a deficient storm drain system results in one to two feet of flooding in the area of Twelfth and Lake Streets. 5.1.1.28 Area 28 — Properties in the Alabama Street, Utica Avenue, and Detroit Street area south of Yorktown Avenue have deficient storm drains and experience up to one foot of flooding during periods of heavy rain. 5.1.1.29 Area 29—One foot of flooding is experienced in the Crabb Lane and Speer Avenue area during periods of heavy rains due to lack of storm drains. 5.1.1.30 Area 30 — One to two feet of flooding water during periods of heavy rain is the result of a deficient storm drain system (lack of storm drains) in the area of Main Street and Garfield Avenue. 5.1.1.31 Area 31 — One foot or more of flooding impacts Pacific Coast Highway from Warner Avenue to Goldenwest Street during periods of heavy rain coupled with high tides. 5.1.2 Repetitive Loss Properties Fifteen properties within the City have received flood insurance benefits twice within a 10-year period since 1978 as a result of heavy rains. FEMA describes these properties as Repetitive Loss Properties. The 15 properties represent 33 claims. These properties are located near the East Garden Grove - Wintersburg Channel (C05), Talbert Channel (D02), East Valley — Fountain Valley Channel (D05), Huntington Beach Channel (D01), Michael Channel, and the juncture of 26 Res. No.2000-85 three channels at Interstate 405, Beach Boulevard, and Edinger Avenue. All are located in areas where localized flooding reoccurs. The majority of the claims happened in 1995 and 1997-1998. Some of these flood claims were based on the inadequacies of the local drainage system with the flood control channels full of water; others were based on poor on-site drainage patterns. During the 1992, 1995, and 1997-1998 flooding events for the repetitive loss properties, the flood control channels were filled to capacity and floodwaters filled the streets and continued to rise until homes were filled. High water levels were maintained for several hours until rainfall diminished and the channel levels receded to allow proper drainage. Repetitive loss properties at the lowest point in neighborhoods where storm drain catch basins are located experienced a deluge of water when heavy rains filled the channels to capacity. In many cases the homes are lower than the channel and receive excess floodwater. In a couple of instances, flood damage was a result of rain entering the dwelling through windows and chimneys and yard grading which allowed water flow directly toward the house. 5.1.3 Santa Ana River History The earliest recorded flooding event occurred in 1810, when adobe buildings were washed into the Santa Ana River. In 1825 the River changed its course and created what is now known as the Balboa Peninsula. Storms in 1861-1862, with constant rain for almost four weeks, created an inland sea in Orange County when the peak flow of 320,000 cubic feet of water per second raged through the Santa Ana Gap. Standing water approximately four feet deep up to four miles from the river lasted about three weeks. This flooding is considered as having a recurrence interval greater than a 200-year flood. Later in 1884, the river cut a new channel. More serious flooding occurred in 1889. Half a million dollars of damage and four deaths were the result of the river running wild through most of western Orange County in 1916. Floods were also recorded in 1925 and 1937, however, they did not match the disaster of 1938. At that time an 8-foot wall of water swept out of the Santa Ana canyon leaving 19 dead. Water flows in the river measured 100,000 cubic feet per second. This disaster led to the construction of the Prado Dam in 1941, Twin floods of 1969 resulted in $21 million in damages and five deaths. Peak water discharge flow reached 77,000 cubic feet per second above the Prado Dam and 6,000 cubic feet per second below the dam. Emergency sandbagging kept the river within its channel as it approached Huntington Beach on its way to the ocean. On February 24, 1969, almost six inches of rain fell, overflowing dams and flooding parks and canyons. 27 Res. No.2000-85 5.2 HIGH TIDES AND HIGH SURF When high tides and high surf occur simultaneously, portions of Pacific Coast Highway are inundated with water. Portions of Pacific Coast Highway are often flooded between Warner Avenue and Seapoint Street. The Public Works Department works closely with the California State Department of Transportation (CalTrans)to ensure that Pacific Coast Highway is protected as much as possible from high surf damage. In the event that the roadway is inundated, traffic is diverted and/or the highway is closed. In 1983, ocean waves reached Pacific Coast Highway between Newland and Magnolia Streets. Heavy rain, high surf, and high tides impact the beaches along Huntington Beach's shoreline. Bolsa Chica State Beach has been inundated by high surf conditions. Areas of the beach, multi-purpose trail, restroom and parking lot areas were flooded. Park facilities were lost to high surf and storm conditions in 1983. The beach is also inundated by debris that washes ashore from the San Gabriel River. Huntington State Beach is impacted by debris that washes onto the beach from flooding impacts upstream along the Santa Ana River. High tides and high surf conditions also erode the beach sand. High tides coupled with heavy rain force stormwater to back up in the flood control channels. This backup may create water to breach the channels. Public Works Department monitors the tide table on a regular basis. When the table indicates a high tide greater than six feet will occur, inflatable gags are placed in storm drains to prevent salt-water intrusion into the local drainage channels within the Sunset Beach area, northwest of Warner to Intrepid Island. Tidal surge was experienced in the Huntington Harbour area following an earthquake in Alaska during 1964. Sandbagging efforts by City personnel and local residents minimized damage to the area. 5.3 TORNADOS In 1978 a waterspout came in off the coast of Huntington Beach causing a tornado that hit Huntington-by-the Sea Mobilehome Park located near Newland Street and Pacific Coast Highway. About 45 mobilehomes were destroyed or seriously damaged. This event led to the creation of an emergency response team program. In 1991 a waterspout came inland causing a tornado that hit Driftwood Mobilehome Park and some residences in the Altanta Avenue and Newland Street area. About 40 mobilehomes and two other residences suffered moderate damage; five residences had minor damage. The City responded to the incident along with the American Red Cross. Canteens were set up along with mental health professionals to attend to the personal needs of the victims. There were 28 Res. No. 2000$5 no injuries and no temporary shelter was required. Since the homeowners were insured from this type of loss, the event was not proclaimed a local emergency. In 1998 a tornado hit the Villa Huntington Mobile Estates located south of Slater Avenue and west of Beach Boulevard. A storage shed and several roofs were blown away by the powerful wind. Traffic signals were non-functioning and power outage lasted approximately two hours in the immediate area. 5.4 BUILDINGS There are over 70,000 buildings in Huntington Beach. Of these approximately 54,500 are 1-4 family structures. Five buildings are listed on the National Register of Historical Structures. 5.4.1 Public Buildings Included in the total number of buildings are the following public facilities: 5 police stations 8 fire stations (one under construction) 1 marine safety building 1 city hall 1 community college 4 high schools 43 elementary and middle schools 5 libraries 3 post offices 4 public maintenance facilities (beaches, public works corporate yard, parks, and water operations) 5 community centers 1 art center 1 parking structure Flood impacts on these buildings may hamper the City's normal operations, flood assistance efforts, and temporary shelter for displaced persons. 5.4.2 Historic/Local Landmarks The City's General Plan identifies many local landmarks considered to be of significant importance to the community. Five of the identified landmarks are listed on the National Register of Federal Historic Places. They are: Newland House, Helm House Furnishing Company, Helm-Worthy House, Garner House, and the City Gym,and pool, which are still used for the original purpose. All are located in repetitive loss areas except the Newland House. Other landmarks include areas of archeological significance such as Edwards Hill and Bartlett Park, and areas where structures constructed during the early 1900s 29 Res. No.2000-85 such as the Townlot area still exist. Flood damage to these properties may significantly diminish their historic value. 5.4.3 Critical Facilities Flooding can impact critical facilities. Critical facilities that may need special attention include one 133-bed hospital and three nursing/rehabilitation centers with a combined total of 448 beds. It is important that ensure safe evacuation procedures can be attained with minimal disruption. Other critical facilities include the electrical generation plant, four electrical substations, and 42 bridges. Flooding at any of the electrical facilities may cause power outages or shortages. If damage occurs to any of the bridges crossing the flood control channels or Santa Ana River, evacuation routes may be seriously hampered. 5.4.4 Hazardous Chemical Facilities Large expansive sites with hazardous materials include Boeing which has 50 percent of all hazardous chemicals in the City, the water and sewage treatment facility, rotary mud dumpsite, major oil company storage facilities, and the oil fields along Pacific Coast Highway and scattered in the Holly-Seacliff and downtown areas. Businesses that store or use hazardous chemicals are monitored by the Fire Department and are identified in the City's Emergency Management Plan. A combination of hazardous materials and floodwaters may be detrimental to life, property, and the environment. 5.5 WETLANDS_, UNDEVELOPED PROPERTIES, AND OPEN SPACE AREAS As previously mentioned, wetlands are designed by nature to hold water and provide habitat for wildlife. When the floodwaters enter the site, problems may occur if the runoff water contains hazardous substances. Waters then become contaminated and wildlife-feeding or nesting areas are affected. Recent oil spills at sea have impacted the shore and wetland areas and necessitated significant cleanup efforts. The Talbert Marsh is a restored wetland and lies inland of Pacific Coast Highway between Brookhurst Street and the Santa Ana River. The Talbert Channel flows through the area and exits into the ocean. The Bolsa Chica Wetland located near Pacific Coast Highway and Warner Avenue is surrounded by the City but lies outside the city limits. (See Exhibit 4.) Huntington Beach has 71 parks, which encompass 577.28 acres. The many local public school sites provide additional open space areas. The park areas, as well as undeveloped areas and play fields adjacent to public schools, have pervious ground surfaces that absorb water naturally and may also contain floodwaters. Within the parks there are lakes that also act as retention basins for 30 Res. No. 2000-85 heavy rains. The lakes include Talbert Lake, Huntington Lake, Shipley Lake, Carr Park Lake, and Sully-Miller Lake. There are also retention areas within Bartlett Park, Good Shepherd Cemetery, Ocean View High School, Oka Elementary School, Argosy Drive east of Graham Street, Home Depot, and adjacent to the equestrian center on Goldenwest Street. There are relatively few areas in the city that have not been developed and/or are vacant. These are depicted in the Vacant Land Survey available in the Planning Department. Preventive measures must be observed to ensure that mudflow is not generated from any vacant/undeveloped site. 5.6 PROTECTIVE MEASURES IN EFFECT OR UNDER CONSTRUCTION 5.6.1 Santa Ana River Mainstem Project Almost thirty years ago planning efforts began to tame the Santa Ana River, which is the greatest flood threat west of the Mississippi River. This project is known as the Santa Ana River Mainstem Project and cost $1.4 billion. A coordinated effort between local, county, state and federal agencies and the business community was realized in 1990 when land was cleared in preparation of construction of the Seven Oaks Dam, a 550-foot high, 3,000-foot-long dam, in San Bernardino County. In 1991 construction began on the lower three miles of the riverbed from Adams Avenue to the Pacific Ocean. The river channel adjacent to Huntington Beach was deepened, widened, and lined with concrete. Later the remaining portion of the river in Orange County was completed or is near completion. The Seven Oaks Dam was completed in 1999. These measures protect Huntington Beach from a 100-year flood. A core component of the Santa Ana River Mainstem Project includes the increase in the Prado Dam's capacity to maintain a major flood. The Prado Dam will be raised 28.4 feet and approximately 2,000 acres added to accommodate the reservoir behind it. This portion of the project when completed will provide protection to the City of Huntington Beach from a 190-year flood. Lack of sufficient funding sources and the Orange County bankruptcy have impacted the progress of the Prado Dam. Recent Federal legislation has appropriated partial funds for this project. The anticipated completion date is expected by 2005. Prado Dam expenses are estimated to be $470 million. 5.6.2 County Projects Following the March 1983 storm, the County intermittently made repairs to its channels. This storm devastated over 100 homes within the Talbert Gap area in southeastern Huntington Beach. Repairs were made to the D01 (Huntington Beach) Channel where channel failure occurred and up to five feet of flooding impacted properties adjacent to the channel. D05 (East Fountain Valley) and D02 (Talbert) Channels were concrete lined at Brookhurst Street and Garfield Avenue where extensive damage occurred to many mobilehomes. 31 Res. No.2000-85 The Talbert Gap outlet was moved 300 feet northwest of the Santa Ana River bridge on Pacific Coast Highway. Reconstruction of the Santa Ana River bridge and Pacific Coast Highway were completed in late 1989. At that time the County granted a conservation easement and fee title to the Huntington Beach Wetland Conservancy to control and manage restoration of a wetlands and wildlife area of 25 acres adjacent to the outlet. In the last 10 years in conjunction with the Santa Ana River Mainstem project, the County has an on-going program to improve, and has constructed portions of several channels to provide 100-year protection. Prior to improving a channel, the County requires reports for each channel that assess the current capacity and demand. They have contracted with various engineering firms to study the various flood control channels and to prepare a recommendation for improvements to meet the 100-year flood capacity. Recently a report for the Talbert Channel was prepared and completed which resulted in on-going improvements. Since 1939 the County has been making improvements to the Talbert and Huntington Beach channels to increase the capacity to 100-year flood protection. Vertical steel sheet piling has been installed to increase the channels' capacity. Orange County's consultant is presently conducting flood studies to determine the necessary changes to improve the remaining County channels to comply with the 100-year minimum capacity. These studies should be completed in the next five years. Until the studies are complete and accepted by FEMA, properties in the SFHA for the D01, D02, and D05 channels will remain as flood zone A99 and the properties in the SFHA for the C05 and C06 channels will remain flood zone A. When completed, these channels will be eligible for improvements by the County as funding permits. Local property tax assessments generate funding for County flood control measures. Funding is also received form FEMA's Hazard Mitigation Grant program and the U.S. Army Corps of Engineers. The County has a seven-year plan for drainage improvements to FEMA's 100-year minimum standard. Only porjects shown in the first year are recommended for inclusion in the budget. All others are subject to change. Flood control improvements for channels within, Huntington Beach that are included in the seven-year plan are shown on the next page. 32 Res. No. 2000-85 COUNTY OF ORANGE SEVEN-YEAR FLOOD CONTROL IMPROVEMENT PLAN Fiscal Caca#io>t1 Es imp e. 2000-2001 C05 Near Gothard and railroad bridge 2,750,000 D01 1,750 ft upstream of Newland to 4,500,000 Atlanta D02 Indianapolis to Adams 500,000 D02 Atlanta to Indianapolis 500,000 2001-2002 C05 Quartz to Magnolia/Edinger 21300,000 D01 Magnolia to 1,750 ft. upstream of 6,400,000 Newland 2002-2003 C05 Magnolia/Edinger to Bushard 5,300,000 D01 Atlanta to Indianapolis 2,600,000 D02 Adams to Yorktown 4,850,000 2003-2004 C05 Bushard to 1600 ft. upstream 4,000,000 2004-2005 D01 Indianapolis to Adams 5,000,000 2005-2006 None 2006-2007 C05 1600 ft. upstream Bushard to 3,000,000 Brookhurst C06 Bushard to Brookhurst 1,300,000 Total 43,000,000 Since 1987, the County has spent$25 million on D- drainage systems with a total of$32.6 million on both C- and D- drainage systems within the county that directly or indirectly benefit the City. Completion of the entire county channel improvements in Huntington Beach is anticipated to occur within the next 10-15 years barring any unforeseen catastrophes. All improvements should ideally begin at the lowest portion of the channel with the work progressing upstream so that the completed portions are capable of containing water from a 100-year storm. The County, however, improves portions of the channels in various areas of the county that will provide protection and not create additional flood problems in other areas. 33 Res. No.2000-85 Until these improvements are completed, certified by FEMA, and the official flood maps are revised, properties located within 100-year flood areas are subject to flood loss and flood insurance requirements. Projects that can increase the flood intervals will enjoy less possibility of flood damage and are not required to be insured from flood damage. A Letter of Amendment was issued by FEMA for 100-year protection improvements to the Anaheim-Barber Channel (CO3) effective February 28, 1996. These improvements protect properties in north Huntington Beach between Rancho Road and Springdale Street adjacent to the City of Westminster from a 100-year flood. Therefore, flood insurance is not required for these properties. 5.6.3 Local Projects There are many local flood control projects that have been completed, under construction, or pending final improvement. These include: ➢ Curbs and gutters have been constructed in Repetitive Flooding Area 2, but there is still more to complete. ➢ Additional catch basins have been constructed in Repetitive Flooding Area 10, however, flooding still remains a concern until additional measures are undertaken. ➢ The Main Street/Garfield Avenue area (Repetitive Flooding Area 14) has been improved with new paving, curb and gutters, which should alleviate future flooding problems in this area. ➢ A pump was added to the pump station in Repetitive Flooding Area 20, but the station is too small to solve the flooding problem. ➢ Demolition and reconstruction of the existing deficient Shields pump station is underway. It is scheduled for completion by October 2001 (Repetitive Flooding Area 6). ➢ In Repetitive Flooding Area T construction of a new storm drain and appurtenances in Goldenwest Street between the C05 channel and Norma Drive is scheduled for completion by October 2000. ➢ Construction of the Slater Channel improvements.began on May 30, 1999, with an anticipated completion date of February 2001. The project consists of concrete lining the existing channel and appurtenances between Springdale and Goldenwest Streets. 34 Rosa Nba MO-05 hilurdy,'Ch,k:nnei re lig.r m it wil> provide 4,00 feet of neW channel at the confluence >it the C0 chars�eia `hi proj cL'is a��affi€� i€ al Clearance from the US Army Corps of Engineers. Funding from,th6 om.rnu€iity Development loc rant programs has.:bee. lloc; d to study s design, antrct!i s to'# '€ Channel (RepetitNe Roodina:Area ',10). The has € it ht ilatl sf new stnr drain and p urtenar ces such as add';rional inlets az,d a gates for intrepid Lane, Prior to the rainy season e cl veer, the i� Iic rl s 1� rtnIent ir�� ct�, clears and maintains the City s fled control channels. rRai gauge readings:are taken at the take Street'Fire Station. and forwarded t the Public Works l e art€nent, mainte€ance divislon, R& advance poss.ibje flood: warning. DUrInq. and,prior to predicted le a-v r rain, the Public Works Department rain patrol areas known to haveexperienced ficodin ,n the oast. Barricades are placed. at intersection ae d'l ag 'placed in str.ta € lec tiara, and storm drains inspected:fbr debris needed., Sandbags are made available to the biic t theCity Yard if time Permits, Citizen volunteers such as ComMuniWErnerg e cy Respons Team (€.,ERT and Radio Amateur Civil, Emergency;, ervi as (RACES) provide fled proteotiom-and assistance to the City and to property owners ;�- ti y Community volunteers assisting in sandbagging' ------..«._._._-•c----'...,.,.,. ,....___ - „�M1 �, :e f,'+, yj% SEE ' '� M'GP 1, , �*p. '2; 6 �'f'C /� �' `"vim '� F r � •�` t ' 1 RESIDUAL FLOUPPLAINS, � _ � rah r+.�,•, F r � t;�n "dN o �w�i1K9•�?JbD'7 A�6SOb110�'E ter, s �u vo�,�wasts;st<so�:mrafx t wwwa=c==oua G:lY 714G0."Kf>nY ,� Y taar s2,x�r "� t n ..: ..t Res, €a 2NO,8 ti 4 pan 8. } SR \ 4 4 «Community Emergency i espcinse Team (CERT)volunteers 5,6A Hood Insurance s a participant'in the NAP, flood inswrance is,avai:labla to Huntington Beach property owners and tenants whether or not the property is located in the. F as identified by FEMA. Flood insurance 's is require, for all p.roperves in the SFH +ith mort a es backed by the federal overn e t. There are: 17,495Str�€ct��re in the City i Ur hdyf orr,S 2, billionp against } €od da ge.' urrercFas�,�aga,total of . d.+ k7t 6.i C[f�:i��5� 1Db f1W1�i"l-s CF Bc:R L7:��u2 '�rvt�+�'+. 2`.l r�..+ 0�k1i� f."ar �> t,-1:lS�Ch.Ea 'yor 17,381rtten posicie toe truetres. ceSU,flood Insurance ie .: 'Million have been paid to local 0itize€�� e to'i�eavy mina and channel malfu ctio ��WY ropy owner ��f�s� �e��r �� d in Mare °1 were not'insured from flood loss, hIese citizens were able to, receive lam'interest loans to repair the e. in 1996 the Santa Any Rig;er floodpf in in Orange County wPIS,determuned b FEMA to protected from€ er flood'by a p ro jectundercotstrction. . This ete€r i i n le l to t € new i€ € rarlce!rate maps �' Cl l� ) that identify € uch of the Ofty.within:a zped l flood: hazard area. The news F fi les rezoned mo t of the city to'flood -o-ne efleative Jan ar; 3, 1997, Followi€0 ce =-fncation of the Santa Ana liver improvements, the FIRMS were again revised rezoning ,portions flood zone A99 to flood zone A due to localized find hazards from Countv and Gigs,owned channels. Approximately one s Qar mile of zone was added to an area P-reVIOUSlY Outside of A99 and appro it t ly five percent of zone A99 was added to zone X Whose, € aps became effective June 14, 0 0� (See Exhibit 17.) 6 J Res. No.2000-85 5.6.5 Seawalls Huntington Harbour is an area consisting of several man-made islands. Seawalls have been constructed along the perimeter of the islands to protect the development from the high tides. The seawalls are owned and maintained by the adjacent development project. A few have been reconstructed in the past few years due to deterioration. A seawallllevee also protects a residential development near the juncture of Talbert Avenue and Graham Street along the City boundary from ocean intrusion from the Bolsa Chica wetland area. 5.6.6 Warning Systems and Evacuation A major nonstructural flood protection measure is the National Waming System (NAWAS). This system identifies severe weather conditions and tsunamis, and is operated by the National Oceanic and Atmospheric Administration through the National Weather Service. The National Weather Service cooperates with State, County, and local officials to alert coastal residents when major storms or tsunamis necessitate precautionary measures be undertaken. The California State Warning System receives information from the NAWAS at the State Office of Emergency Services (OES) headquarters in Sacramento. This system extends to the Orange County Operational Area (storm center), which advises local jurisdictions. During a major storm, the Orange County Storm Center is activated. This center provides predicted flood events and related data to the City's Emergency Operation Center (EOC)which is located at City Hall. EOC is a state of the art facility that was funded in part by FEMA and is activated when a threat to the City is imminent. EOC has established operation procedures for emergencies including flooding. When the City receives flood warnings or a threat exists, flood warnings are disseminated over local radio stations KWVE (107.9 FM) and KXMX (95.9 FM) utilizing Emergency Alerting Systems and local cable TV HBTV-3 (Channel 3). If EOC determines that evacuation is necessary, the City's waming sirens located at each fire station will be sounded. This alerts area residents to check the radio or television for further information and advice. Other forms of notification may include helicopter and vehicle public address loud speakers and door-to-door canvassers. The Police Department is responsible for alerting and warning the public in areas where flooding is imminent. The Fire Department assists in evacuating non- 37 4 Res. No. 2000-85 ambulatory citizens. Marine Safety staff assists in areas where boats may be used for evacuation. 5.6.7 Zoning and Construction Regulations The City has adopted floodplain development regulations to ensure that new projects are constructed in a flood safe manner. At the time a property owner desires to develop a vacant site, planning and zoning approval must be received to confirm that the project complies with local zoning requirements including floodplain development regulations. Building and grading permits must be issued that confirm the development will be designed and constructed in compliance with drainage and building codes adopted by the City. New development must also comply with the National Pollution Discharge Elimination System (NPDES) requirements to ensure that runoff from the site does not affect any water source. Prior to final building permit inspection, an elevation certificate must be submitted verifying that a building constructed in the floodplain was elevated one foot above the base flood elevation. 5.6.8 Beach/Wetland Protection The State Department of Parks and Recreation participates with the County, State Department of Boating and Waterways, and the US Army Corps of Engineers in the regional sand replenishment project that occurs on a five-year cycle. This ensures that there is adequate sandy beach to minimize flooding of property from ocean activity. Relocating a beach park vehicle exit and constructing a tall sand berm to prevent surf waters from flooding Pacific Coast Highway has mitigated loss of state beach facilities. Sand dunes protect the fresh water wetlands along Pacific Coast Highway between Magnolia and Brookhurst Streets. As mentioned in Section 5.6.7, a seawall/levee protects a residential neighborhood along the southwesterly City boundary and also provides protection from neighborhood drainage into the wetlands. 5.7 FISCAL IMPACT 5.7.1 Funding Current funding for City drainage improvements is derived from the City's General Fund and drainage fees from developers. Drainage fees are assessed on new construction and used only in the drainage area where the construction occurs. As a result, drainage districts with new development areas such as Holly-Seacliff receive more funding than a district with older neighborhoods and little or no new construction. Improvements in other areas must be budgeted and authorized by the City Council. 38 Res. No.2000-85 Grant funding is a possible source of revenue for drainage improvements. The City has received funding from several sources including FEMA, the California Office of Emergency Services, and the Community Development Block Grant (CDBG) program. 5.7.2 Flood Damage Expenses The City incurs expense from flooding events. These expenses include activation of the EOC; barricading streets; patrol, clean up of mud, water, and debris; and fallen tree removal and replacement. EOC activation along with damage and response costs to the City since 1988 are over $4 million and include: 1988 Winter storm and pier damage $ 1,300,000 1992 Flooding $ 104,000 1995 Flooding $2,600,000* 1997 El Niho Flooding $ 160,000 1998 El Nino Flooding $ 112,000 Total $ 4,276,000 *The City was declared a disaster site on January 5, 1995, following the heavy rains that deluged Huntington Beach. Cities are eligible to receive financial assistance following a disaster that enables them to recover from the natural disaster. FEMA reimburses a maximum of 75% of the eligible damage and response costs. Consequently, a claim was submitted to FEMA to recover the expenses incurred from the flood disaster. A few of the expenses are listed on the next page. 39 Res. No. 2000-85 1995 FEMA CLAIM! ITEMS COSTS Marine Safety response $14,320 Fire Department response $5,102 Police De artment response $9,502 Public Works response $70,558 Trees $25,018 Sewer line cave-in $18,166 Street repairs $10,412 Sea curtains $13,496 Trash racks $10,625 Prince park $110,025 Debris removal $48,001 Slater Channel $235,690* Bluffto Park $1,943,604 Natural gas $21,195 Lifeguard tower $2,435 Horse stables $5,072 Corsican Channel $14,312 Slater Channel temporary repairs $20,026 'This cost was deobligated but resulted in a final obligation of$909,934. 5.7.3 Flood Management/Prevention Expenses The Planning Department sends an annual flood protection/information brochure to over 26,000 residents located in the floodplain. This brochure includes a flood map, flood warning and flood insurance information, property protection suggestions, flood safety tips, and local flooding history. Printing and mailing cost are approximately$6,000. The winter edition of the Sands, a Community Services activities publication, also includes much of the same information Total yearly average cost for flood management/prevenbon by the Public Works Department maintenance crews is $101,815. This includes: • Annual local drainage channel inspection and cleaning $23,697 • storm preparations $50,048 • storm duty $21,302 • high tide patrol $6,767 40 Res. No.2000-85 Currently the City operates 15 pump stations with 47 pumps with an annual maintenance and operational budget of$300,000 or approximately $6,400 per pump. The actual maintenance and operational costs are closer to $1,000,000 or approximately $21,280 per pump. Property operating procedures should include regularly scheduled equipment maintenance, replacement, and cleaning. The replacement cost for a single pump with appurtenances is estimated at $900,000. 5.7A Financial Assistance During 1998, the City received FEMA mitigation grant funding of$3.3 million for Slater Channel and $468,000 to realign Murdy Channel. In 1999, $1.6 million FEMA mitigation grant funding was received for Shields pump station. In November 1999, $300,000 in federal funds was received to study the bluff erosion along Pacific Coast Highway and to determine mitigation measures. Total cost of the 27-month study is estimated at $1.02 million. The City expects to apply for an additional $210,000 grant in 2000 and provide matching funds for the project. In late 1999, the City received $425,000 in reimbursement by the federal government for the City's handling of floods caused by severe storms in past years. In 2000, the City received $397,800 in CDBG funds for the Michael Channel. These grants will be used to complete the flood-related projects identified in the City's Capital Improvement Program during fiscal years 1999-2000 and 2000-2001. These projects are shown on below. IMPROVEMENT CITY $ FEMA $ C©BG $ TOTAL $ Goldenwest St. storm 346,540 0 0 346,540 drain Slater Channel 827,484 2,482,480 0 3,309,964 Shields pump station 611,664 1,245,000 0 1,856,664 Murdy Channel 106,250 318,750 0 425,000 realignment Intrepid t_n. storm 130,000 0 0 130,000 drain Michael Channel 0 0 397,800 397,800 Total 2,021,938 4,046,230 397,800 6,465,968 41 SECTION 6.0 GOALS Res. No.2000-85 6.0 GOALS The Flood Management Plan Committee reviewed the goals of the Huntington Beach General Plan and seven were found to be appropriate to the Flood Management Plan. ❖ Flooding (EH4}: Eliminate to the greatest degree possible, the risk from flood hazards to life, property, public investment and social order in the City. ❖ Storm Drainage U3): Provide a flood control system which is able to support the permitted land uses while preserving the public safety; upgrade existing deficient systems and pursue funding sources to reduce the costs of flood control to the City. 4• Tsunami (EH5): Protect human life, to the greatest extent feasible, from tsunamis and seiche hazards. ❖ Biological Resources (ERC2): Protect and preserve significant habitats of plant and wildlife species, including wetlands for their intrinsic values. ❖ Erosion (EH2): Reduce the potential threat for mesa edge and bluff erosion hazards, and the potential for beach sand loss. ❖ Open Space (LU14}: Preserve the City's open space. ❖ Historical Resources HCR1): Promote the preservation and restoration of the sites, structures and districts which have architectural, historical, and/or archaeological significance to the City of Huntington Beach. 42 Res. No. 2000-85 SECTION 7.0 POSSIBLE ACTIVITIES Res. No. 2000-85 7.0 POSSIBLE ACTIVITIES The CRS guidelines require the FMP to identify all the activities considered by the Committee and state why an activity was not recommended in Section 8.0. The Committee considered many possible ways to reduce flood losses and to attain the goals applicable to the Flood Management Plan. At almost every meeting, the Committee stated that the County's regional drainage system affects flooding in Huntington Beach and that the City should be pro-active in all developments in the regional drainage area. There was considerable concern that most of the flood control channels (both City and County owned) were not in compliance with FEMA's 100-year standard. The storm drains, channels and pump stations should be improved to this standard as soon as economically possible. Until the systems are upgraded, the Committee believes that development should be limited to minimize future flooding impacts. Whenever private property drainage problems are created by water flow from public property, it should be corrected. The Committee believes that the Master Plan of Drainage should be updated and implemented on an annual or biennial basis. Many of the activities cited in the CRS application were specifically recommended to continue to be implemented. The following activities were discussed but are not recommended for implementation: • Limit development until flood control deficiencies corrected • Become involved in all projects in regional drainage area • Establish citywide drainage fee • Building acquisition or relocation For the following reasons: • Drainage studies and improvement plans are required-to ensure no drainage impact to surrounding area. • . Projects in northern part of drainage area are not forwarded to the city for review and comment. • City Council will review funding recommendations from the infrastructure committee. • Insufficient funds to acquire/relocate floodprone buildings. The activities recommended in Section 8.0 were then compared to the six mitigation categories suggested by FEMA. Each of the categories has two or more recommended activities to mitigate flood hazard to the city. Preventive: Activities that include planning and zoning, open space preservation, floodplain regulations, drainage system maintenance, stormwater management, 43 Res. No.2000-85 and dune and beach maintenance. These are usually enforced by Planning, Building, and Public Works Departments. Property Protection: These activities are usually undertaken by property owners on a case-by-case basis and include relocation, acquisition, building elevation, floodproofing, sewer backup protection, and insurance. Natural Resource Protection: Activities that preserve or restore natural areas or the natural functions of floodplains include erosion and sediment control, best management practices, and wetland protection. These are implemented by the Planning and Public Works Departments. Emergency EmeEgency Services: Activities that are undertaken during a flood to minimize its impact include warning and evacuation, critical facility protection, and health and safety maintenance. These activities are the responsibility of the Emergency Operations Center (EOC), safety personnel (Fire, Police, and Marine Safety), and Public Works Department. Structural Proiects: Activities that keep floodwaters away from an area include seawalls, water diversion, channel modifications, beach nourishment, and storm drainage system improvements. They are designed by engineers and managed by city and county public works staff. Public Information: Activities that advise property and business owners about the hazards, ways to protect people and property from flood damage, and the natural and beneficial functions of the local floodplain are implemented by the Planning Department. The Library, EOC, and the Public Information office may provide assistance. 44 @S.No. SECTION 8.0 RECOMMENDATION Res. No. 2000-85 8.0 RECOMMENDATION The Committee recommends the following activities. These activities will achieve the goals of the Flood Management Plan and General Plan and will supplement the implementation programs identified in the General Plan. Existing and/or similar General Plan implementation programs are shown in parenthesis. 8.1 Goal EH4 - Flooding: Eliminate to the greatest degree possible, the risk from flood hazards to life, property, public investment and social order in the City. 8.1.1 Continue to enforce and update floodplain regulations when revised by the Federal government (I-EH 15) Responsible department: Planning Funding source: General fund Timetable: ongoing 8.1.2 Protect public facilities from flooding (I-EH 2d) Responsible department: Public Works Funding source: General fund Timetable: ongoing 8.1.3 Assist managers and owners of critical facilities as listed in Section 5.4.3 to develop flood protection plans Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.1.4 Encourage floodproofing and retrofitting property/structures to prevent substantial flood damage and provide technical information (I-EH 9-b) Responsible department: Planning, Building, Fire (Emergency Services) Funding source: not applicable Timetable: ongoing 8.1.5 Continue to update, distribute, and provide flood protection information and materials (I-EH 8a) Responsible department: Planning, Library, and Fire (Emergency Services) Funding source: General fund Timetable: ongoing 45 Res. No.2000-85 8.1.6 Maintain adequate flood insurance on public structures Responsible department: Administrative Services Funding source: General fund Timetable: ongoing 8.1.7 Provide floodplain information to property and business owners, realtors, and prospective buyers and encourage flood insurance (I-EH 8d) Responsible department. Planning Funding source: not applicable Timetable: ongoing 8.1.8 Maintain close liaison with nearby cities and with County, State and Federal agencies (I-EH ex and I-EH 2h) Responsible department: Public Works, Planning and Administration Funding source: not applicable Timetable: ongoing 8.1.9 Continue to participate in the National Flood Insurance Program and Community Rating System (I-EH 14) Responsible department: Administration and Planning Funding source: General fund Timetable: ongoing 8.1.1 0 Continue to implement the City's emergency operation procedures as outlined in the City's Emergency Management Plan, in particular, the Flood Warning and Evacuation procedures (I-EH 13b) Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.1.11 Continue to utilize citizen volunteers, e.g., CERT and RACES (I-EH 13c) Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.1.12 Continue to provide a sandbag program Responsible department. Public Works Funding source: General fund Timetable: ongoing 46 Res. No.2000-85 8.1.13 Encourage the State to modify the roadway profile of Pacific Coast Highway between Warner Avenue and Goldenwest Street to prevent street closure due to flooding. Responsible department. Public Works, Administration, Planning Funding source: General fund Timetable: January 2001 8.2 Goal U3 -Storm Draina e: Provide a flood control system which is able to support the permitted land uses while preserving the public safety; upgrade existing deficient systems and pursue funding sources to reduce the costs of flood control to the City. 8.2.1 Upgrade the City's flood control system (storm drains, catch basins, pump stations, and channels) to current FEMA standards (100-year flood) and concentrate on the repetitive flood areas first. (I-EH 1a) Responsible department: Public Works Funding source: General fund, Capital improvement program, drainage fees, FEMA mitigation funds, Community Development Block Grant funds Timetable: October 2020 8.2.2 Quarterly the City Council shall lobby the County to correct, upgrade, and maintain the County's flood control system in the city to current FEMA standards (100-year flood) Responsible department., City Council Funding source: General fund Timetable: by January 2001 and quarterly thereafter 8.2.3 Evaluate existing street conditions for replacement and/or installation of facilities to allow proper conveyance of storm flows to the city's flood control systems (1-U3 9) Responsible department., Public Works Funding source: Measure "M", Gas tax, General fund Timetable: January 2010 8.2.4 Maintain the City's flood control system and continue biannual inspection and cleaning of City's flood control system (I-EH 1a) Responsible department. Public Works Funding source: General fund Timetable: ongoing 47 Res. No.2000-85 8.2.5 Update the City's Master Plan of Drainage to evaluate the effectiveness of the City's flood control system (I-EH 1a and 1-U 4) Responsible department: Public Works Funding source: General fund, drainage fees Timetable: October 2001 8.2.6 Lobby the federal, state and county governments to study, pursue and expand the wetlands from Beach Boulevard to Brookhurst Street for floodwater mitigation. Responsible department. Public Works, Administration, Planning Funding source: General fund Timetable: ongoing 8.2.7 Evaluate and upgrade open areas, e.g., Meadowlark Golf Course, Central Park, Good Shepherd Cemetery, to eliminate offsite drainage and subsequent impact to private property Responsible department: Public Works Funding source: to be determined Timetable: ongoing 8.2.8 Continue to support reconstruction of deteriorating seawalls Responsible department. Planning Funding source: not applicable Timetable: ongoing 8.2,9 Pursue funding from County, State and Federal agencies (1-U 6) Responsible department: Public Works and Administration Funding source: not applicable Timetable: ongoing 8.2.10 Develop and support new funding sources to help accomplish drainage goals Responsible department. Public Works, Administration, Administrative Services Funding source: to be determined Timetable: ongoing 8.2.11 Continue to participate in County watershed studies and programs Responsible department: Public Works Funding source: General fund Timetable: ongoing 48 Res. No. 2000-85 8.3 Goal EH3 -Tsunami: Protect human life, to the greatest extent feasible, from tsunamis and seiche hazards. 8.3.1 Update the Tsunami Emergency Operation plan, Operations Plan — 2, as needed (I-EH 2a) Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.3.2. Continue to provide tsunami warning to the community (I-EH 17) Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.3.3 Educate the public regarding the potential threat of a tsunami Responsible department: Fire (Emergency Services) Funding source: General fund Timetable: ongoing 8.4 Goal ERC2 - Bological Resources: Protect and preserve significant habitats of plant and wildlife species, including wetlands for their intrinsic values. 8.4.1 Implement best management practice plans and National Pollution Discharge Elimination Plans (1-U 9) Responsible department: Public Works and Planning Funding source: General fund Timetable: ongoing 8.4.2 Investigate and install in-line wetlands in drainage courses where ever feasible Responsible department: Public Works Funding source: General fund, Drainage fees, FEMA mitigation funds, Community Black Grant funds Timetable: ongoing 8.4.3 Prohibit filling of wetlands except as permitted by the General Plan (I-ERC le) Responsible department. Planning Funding source: not applicable Timetable: ongoing 49 Res. No.2000-85 8.4.4 Encourage the State to maintain the coastal dunes adjacent to the Bolsa Chica Wetlands and in the Huntington Beach Wetlands to better protect the areas from storm surges Responsible department: Community Services Funding source: General fund Timetable: ongoing 8.4.5 Continue the Coastal Conservation District zoning on the wetlands Responsible department. Planning Funding source: not applicable Timetable: ongoing 8.5 Goal EH2 — Erosion: Reduce the potential threat for mesa edge and bluff erosion hazards, and the potential for beach sand loss. 8.5.1 Establish building setbacks from all slopes including mesa and bluff edges Responsible department: Planning Funding source: General fund Timetable: October 2002 8.5.2 Participate.in the bluff (between Goldenwest and Seapoint Streets) erosion study and implement recommendations Responsible department: Public Works Funding source: General fund Timetable: ongoing 8.6 Goal LU14 - Open Space: Preserve the City's open space. 8.6.1 Limit construction in existing open space areas only to necessary structures such as restrooms, picnic shelters Responsible department: Planning and Community Services Funding source: not applicable Timetable: ongoing 8.6.2 Evaluate the possibility of the City purchasing surplus school sites to allow playfields to remain as open areas and provide for floodwater retention areas Responsible department: Community Services Funding source: General fund Timetable: ongoing 50 Res. No.2000-85 8.7 Goal HCR1 - Historical Resources: Promote the preservation and restoration of the sites, structures and districts which have architectural, historical, and/or archaeological significance to the City of Huntington Beach. 8.7.1 Encourage property owners to floodproof historical structures (I-EH 9b) Responsible department: Planning Funding source: General fund Timetable: ongoing 8.7.2 Encourage property owners of historical structures to maintain adequate flood insurance (I-EH 8d) Responsible department. Planning Funding source: General fund Timetable: ongoing 8.8 Recommended Activities Matrix (see following pages) 51 Flood Management Plan Recommended Activities Y a c O U. :o 12 « = - t c u c y p E � d a V 'C N 'E C a 'a V r� a a Goal Activity Responsible Department Schedule Status EM4-Flooding 8.1.1-Continue to enforce and update floodplain X Ongoing regulations when revised by the Federal government 8.1.2-Protect public facilities from flooding X Ongoing 8.1.3-Assist managers and owners of critical X Ongoing facilities as listed in Section 5.4.3 to develop flood protection plans 8.1.4-Encourage floodproofing and retrofitting X X X Ongoing property/structures to prevent substantial flood damage and provide technical information 8.1.5-Continue to update,distribute,and provide X X X Ongoing flood protection information and materials 8.1.6-Maintain adequate flood insurance on public X Ongoing structures 8.1.7-Provide floodplain information to property X Ongoing and business owners,realtors,and prospective buyers and encourage flood insurance 8.1.8-Maintain close liaison with nearby titles and X X X Ongoing with County,State,and Federal agencies m 8.1.9-Continue to participate in the National Flood X X Ongoing o Insurance Program and Community Rating System 0 0 0 i oa 52 c go a c > a o u C S! C d in O O E 7 E E U U °' a Goal Activity Responsible Department Schedule Status 8,1.10-Continue to Implement the City's X Ongoing emergency operation procedures as outlined in the City's Emergency Management Plan,in particular, the Flood Warning and Evacuation procedures 8.1.11 -Continue to utilize citizen volunteers,e.g., X Ongoing CERT and RACES 8.1.12-Continue to provide a sandbag program X Ongoing 8.1.13—Encourage the State to modify the X X X Ongoing roadway profile of Pacific Coast Highway between Warner Avenue and Goidenwest Street to prevent street closure due to flooding U3-Storm 8.2,1 -Upgrade the City's flood control system X October 2020 Drainage (storm drains,catch basins,pump stations,and channels)to current FEMA standards(100-year flood)and concentrate on the repetitive flood areas first Quarterly the City Council shall lobby the X by January County to correct,upgrade,and maintain the 2001 and County's flood control system to current FEMA quarterly standards(100-year flood) thereafter 8.2.3-Evaluate existing street conditions for X January 2010 replacement and/or installation of facilities to allow proper conveyance of storm flows to the city s flood control systems 8.2.4-Maintain the City's flood control system and X Ongoing continue biannual inspection and cleaning of City's flood control system m N Q h1 G O O 53 CA o um 'C O LL '8 i U ,,,, C r.U_ to3 yv0 Em FL 2 E Eu) 3 E E U Goal Activity Responsible Department Schedule Status 8.2.5-Update the City%Master Plan of Drainage to X October 2001 evaluate the effectiveness of the City's flood control system 8.2.6-Lobby the federal,state and county X X X Ongoing governments to study,pursue and expand the wetlands from Beach Blvd.to Brookhurst St.for floodwater mitigation 8.2.7-Evaluate and upgrade open areas,e.g., X Ongoing Meadowlark Golf Course,Central Park,Good Shepherd Cemetery to eliminate offsite drainage and subsequent Impact to private property. 8.2.8-Continue to support reconstruction of x Ongoing deteriorating seawalls 8.2.9-Pursue funding from County,State and X X Ongoing Federal agencies 8.2.1--Develop and support new funding sources X X X Ongoing to help accomplish drainage goats 8.2.11-Continue to participate in County X Ongoing watershed studies and programs Eli5-Tsunami 8.3.1 -Update the Tsunami Emergency Operation X Ongoing plan,Operations Plan 2,as needed 8.3.2-Continue to provide tsunami warning to the X Ongoing community 8.3.3-Educate the public regarding the potential X Ongoing threat of a tsunami z 0 N O O O 54 C6 i �, M o V V � Q 4 Goal Activity Responsible Department Schedule Status ERC2-Biological 8.4.1-Implement best management practice plans X X I Ongoing Resources and National Pollution Discharge Elimination Plans 8.4.2-Investigate and install in-line wetlands in X Ongoing drainage courses whenever feasible 8.4.3-Prohibit filling of wetlands except as allowed X Ongoing by the General Plan 8.4.4—Encourage the State to maintain the coastal X Ongoing dunes adjacent to the Balsa Chica wetlands and in the Huntington Beach wetlands to better protect the areas from storm surges 8.4.5—Continue the Coastal Conservation District X Ongoing zoning on the wetlands EH2-Erosion 8.5.1—Establish building setbacks from all slopes X October 2002 Including mesa and bluff edges 8.5.2—Participate in the bluff(between Goldenwest X Ongoing and Seapolnt Streets)erosion study and implement recornmendatlons LU14-Open 8.6.1 -Limit oonstruclion in existing open space X X Ongoing Space areas only to necessary structures such as restrooms,picnic shelters 8.6.2—Evaluate the possibility of the City X Ongoing purchasing surplus school sites to allow playflelds to remain as open areas and provide for floodwater retention areas >a ro H z o 0 0 55 �° M 3 J y m o E 2 m =y Ey 0 a U U a a Goal Activity Responsible Department Schedule Status Ongoing HCR1-Historical 8.7.1-Encourage property owners to floodproof X Resources historical structures -T 8.7.2-Encourage property owners of historical Ongoing Ongoing structures to maintain adequate flood Insurance m z a ns 0 0 0 56 t�7Dn Res. No.2000-85 SECTION 9.0 IMPLEMENTATION Res. No. 2000-85 9.0 IMPLEMENTATION The Planning Department will maintain the Floodplain Management Plan. The Planning Director will be responsible for ensuring the overall implementation of the plan and for presenting an annual update to the Planning Commission and City Council. The update will include an overview of the plan and the progress made over the preceding 12 months to implement the recommendations listed in Section 8.0. 57 Res. No.2000-85 10.0 REFERENCES City of Huntington Beach Emergency Management Plan City of Huntington Beach General Plan —adopted May 13,1996 County of Orange, Public Facilities and Resources Department Flood Insurance Study for the City of Huntington Beach, Federal Emergency Management Agency—August 16, 1982 Flood Insurance Study for the County of Orange and Incorporated Cities, Federal Emergency Management Agency— 1989, 1992, 1995, 1997 editions Flood Study, City of Huntington Beach Planning Department—April 1974 Geotechnical Inputs, City of Huntington Beach Planning Department— February 1974 National Flood Insurance Program Seismic-Safety Element, City of Huntington Beach Planning Department— October 1974 State of California Department of Parks and Recreation State of California Department of Water Resources Technical Background Report for the City of Huntington Beach General Plan Update — July 2, 1992 The Orange County Register US Army Corps of Engineers, Los Angeles District 58 Res.No.200"5 SECTION 11 .0 GLOSSARY Res. No.2000-85 11.0 GLOSSARY 100-year flood A flood having one percent chance of being equaled or exceeded in any given year (also called based flood). Acre-feet A measurement of water volume. One acre foot equals 325,851 gallons. Catch basin An opening in the street adjacent to the curb that allows water from the street to flow into an underground drainage pipe. Critical facility Facilities that either provide emergency services or house and serve many people who would be injured or killed in a case of disaster damage to the facility, e.g., r hospitals, emergency service, utility facilities, and communication. Culvert A closed conduit for the passage of stormwater under a highway, railroad, or other embankment. Detention basin An area used to decrease the peak flow form a drainage area by storing a portion of the runoff permanently. Drainage area An area that uses a common storm drain or channel system. Erosion The process by which soil and rock are detached and moved by running water, wind, ice, and/or gravity. Facilities Components of the storm drain system, such as catch basins, pipes, manholes, and channels. Flood control channel An open conduit usually trapezoidal or rectangular in shape used to move extremely large amounts of water through a drainage area. 59 Res. No.2000.85 Flood Insurance Rate Map (FIRM) The official map on which areas of special flood hazard, the risk premium zones, and the floodway applicable to the community are delineated. Flood or flooding A general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters; the unusual and rapid accumulation of runoff of surface waters from any source; mudslides; and condition resulting from flood-related erosion. Floodplain Any land area susceptible to being inundated by water from any source. Gutter A paved surface adjacent to a curb for draining water at the edge of a street or road. Infrastructure Facilities owned by the City that require on-going maintenance and eventual replacement. Landslide A general term for a falling mass of soil or rocks. Levee A raised area bordering an irrigated area, river or other body of water designed to prevent water from overflowing. Master Plan of Drainage An engineering report outlining the drainage facilities needed for improvement and the financing of the proposed drainage systems by the land's tributary to the given facility. National Geodetic Vertical Datum A datum used to reference base flood of 1929 (NGVD) elevations (also know as mean sea level). Peak water flow The amount of water flow measured in cubic feet per second. 60 Res. No.2000-85 Pump station A building equipped with one or more pumps designed to lift water from one area to another. Reservoir A body of water collected and stored for future use in a natural or artificial lake or structure. Retention basin A depressed area of land designed by nature or manmade to retain water for a short period of time. Sand dunes Naturally occurring accumulations of sand in ridges or mounds landward of the beach. Special flood hazard area (SFHA) Land located in a floodplain within a community subject to a one percent chance of flooding in any given year (100- year flood). Storm drain An enclosed conduit (pipe) intended for the reception and transfer of stormwater through a drainage area. Storm drainage system A system composed of pipes, catch basins, gutters, channels, and pump stations designed to transport stormwater to a larger body of water e.g., lake, bay, ocean. Subsidence The gradual, local settling, or sinking of the earth's surface with little or no horizontal motion; usually the result of gas, oil, or water extraction. Tributary A storm drain and/or channel flowing into a larger storm drain and/or channel. Velocity The rate of water flow measured in feet per second. 61 Res. No.2000-85 Wetland Lands which may be covered periodically or permanently with shallow water and include saltwater marshes, freshwater marshes, open or closed brackish water marshes, swamps, mudflats, and fens. 62 Res. No. 2000-85 STATE OF CALIFORNIA ) COUNTY OF ORANGE } ss: CITY OF HUNTINGTON BEACH } I, CONNIE BROCKWAY, the duly elected, qualified City Clerk of the City of Huntington Beach, and ex-off icio 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 the 5th day of September, 2000 by the following vote: AYES: Julien, Sullivan, Harman, Garofalo, Dettloff, Bauer NOES: None ABSENT: Green ABSTAIN: None City Clerk and ex-officio C erk of the City Council of the City of Huntington Beach, California