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Flood Hazard Mitigation Report INTERAGENCY FLOOD HAZARD MITIGATION REPORT ~ in Response to the February 2l, 1986 Disaster Declaration (FE!{A-758-DR) COVERING the California Counties of Alameda, Alpine, Amador, Butte, Calaveras, Colusa, Contra Costa, Del Norte, EI Dorado, Fresno, Glenn, Humboldt, Lake, Lassen, Madera, Marin, Mendocino, Modoc, Napa, Nevada, Placer, Plumas, Sacramento, San Joaquin, San Mateo, Santa Clara, Santa Cruz, Sierra, Solano, Sonoma, Sutter, Tehama, Trinity, Tolumne, Yolo, and Yuba. Prepared by the Region IX Interagency Flood Hazard Mitigation Team: Federal Emergency Management Agency Department of Agriculture Department of Army Department of Commerce Department of Education Department of Health & Human Services Department of Housing & Urban Development Department of Interior Department of Transportation Environmental Protection Agency Small Business Administration State of California, Office of Emergency Services State of California, Department of Water Resources MARCH 15, 1986 TABLE OF CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PART I: PART II: PART III: PART IV: PART V: APPENDICES OVERV IEW . . . . . . . . . . . . . . . . . . . . . . 6 DEVELOPMENT OF RECOMMENDATIONS ........... 9 GENERAL RECOMMENDATIONS .11 Urbanization & Structural Solutions . Floodplain Management & Insurance Flood Warning & Data Collection . . . . 12 . . 16 . . . . . . 19 SITE SPECIFIC RECOMMENDATIONS . 21 Russian River .......... Sacramento-San Joaquin Delta Napa River . . . . . . Sacramento County . . . . . . . . . 22 . . 26 . 30 . . 33 PAST RECOMMENDATIONS ................ 36 APPENDIX A APPENDIX B Requirements of Section 406, P.L. 93-288 Synoptic Situation - Storm series of February 12-21, 1986, NOAA/NWS Executive Order 11988, Floodplain Management APPENDIX C INTRODUCTION On February 21, 1986, the President declared a major disaster in the State of California (FEMA-758-DR-CA). Figure 1 is a detailed list of the declared counties. This report transmits the recommendations of the Region IX Interagency Flood Hazard Mitigation Team (IHMT) to the Federal Emergency Management Agency (FEMA) Regional Director, the Federal agencies that are a party to the Agreement, and the affected state and local governments. Purpose of the Report The report and recommendations of the team are intended to provide the framework for flood hazard mitigation during the reconstruction process to reduce the potential for future flood losses. Overview of Authority and Background Since 1936, Federal, State and local governments have expended in excess of $12 billion for structural solutions to flood problems in the United States. In spite of this investment, flood losses have continued to rise. In an effort to stem continuing increases in disaster relief programs and development pressures on the nation's floodplains, federal emphasis shifted toward a comprehensive and coordinated approach to floodplain management. An Office of Management and Budget memorandum, dated July 10, 1980, provides the basis for the establishment of regional interagency and intergovernmental hazard mitigation teams designed to promote a comprehensive approach to flood hazard mitigation during the post- flood recovery process. These teams were then formulated under the Interagency Agreement for Non-Structural damage Reduction Measures of December 15, 1980. An interagency task force in Washington, D.C. was also established by the Interagency Agreement to coordinate activities and facilitate funding to implement the recommendations in this report. The Office of Management and Budget directive required that a report be prepared by the team within 15 days of a Presidential disaster declaration, that the mitigation activities recommended in the report emphasize non-structural measures, and that Federal agencies combine their recovery actions to achieve economy of losses to the fullest extent practicable. In extraordinary circumstances involving a large scale major disaster, the report may be prepared within thirty (30) days. This report was prepared within 21 days. The report is considered to be a conceptual guide for all Federal agencies providing recovery assistance in the disaster. The FEMA/ State/Local Hazard Mitigation Coordinators (HMe) also use this report as guidance to implement the requirements of Section 406, P.L. 93-288. The Section 406 requirements are explained in Appendix A. Figure 1 DECLARED COUNTIES FEMA-758-DR-CA Date Declared Individual Public COUNTY Assistance Assistance Alameda 3/6 3/8 Alpine (adj acent) 2/27 3/8 Amador (adjacent) 2/27 3/8 Butte (adjacent) 2/27 3/8 Calaveras 2/27 3/8 Colusa (adjacent) 2/27 3/8 Contra Costa 3/6 3/8 Del Norte (adjacent) 3/10 NO EI Dorado 2/27 3/8 Fresno 3/6 NO Glenn 2/25 3/8 Humboldt 2/25 3/8 Lake 2/21 3/8 Lassen (adjacent) 2/27 3/8 Madera (adj acent) 3/6 NO Marin 2/21 3/8 Mendocino 2/27 3/8 Modoc 2/25 3/8 Napa 2/21 3/8 Nevada (adjacent) 3/12 3/8 Placer 2/27 3/8 Plumas 2/27 3/8 Sacramento 2/21 3/8 San Joaquin 2/27 3/8 San Mateo 3/6 3/8 Santa Clara 2/21 3/8 Santa Cruz 2/21 3/8 Sierra (adjacent) 2/27 3/8 Solano 2/21 3/8 Sonoma 2/21 3/8 Sutter (adjacent) 2/27 3/8 Tehama (adjacent) 2/27 3/8 Trinity (adjacent) 3/12 3/10 Tuolumne (adjacent) 2/27 3/8 Yolo (adjacent) 2/27 NO Yuba 2/21 3/8 2 FEMA will be responsible for the overall coordination of the recommen- dations and will prepare a Post Flood Recovery Progress Report which is due on June 13, 1986. 3 GLOSSARY ALE RT Automated Local Evaluation in Real Time BLM Bureau of Land Management; Department of the Interior CSC Computer Sciences Corporation DOC Department of Commerce DOl Department of the Interior DOT Department of Transportation DWR Department of Water Resources (State) ED Department of Education EPA Environmental Protection Agency FEMA Federal Emergency Management Agency FIA Flood Insurance Administration FIRM Flood Insurance Rate Map HHS Health and Human Services HMC Hazard Mitigation Coordinator HUD Department of Housing and Urban Development IHMT Interagency Hazard Mitigation Team NFIP National Flood Insurance Program NOAA National Oceanic and Atmospheric Administration; Department of Commerce NWS National Weather Service; National Oceanic and Atmospheric Administration; Department of Commerce OES Office of Emergency Services (State) OMB Office of Management and Budget SBA Small Business Administration 4 SCS Soil Conservation Service; United States Department of Agriculture USACE United States Army Corps of Engineers; Department of Army USBR United States Bureau of Reclamation; Department of Interior USGS United States Geological Survey; Department of the Interior 5 P ART I OVERVIEW The Disaster A series of storms produced a heavy amount of rainfall throughout much of California during the ten day period from February 11 to February 21, 1986. The storms reached a peak on Sunday and Monday, February 16 and 17. For about 36 hours beginning Sunday afternoon, nearly continuous heavy rains from ten to as much as 27 inches fell in the mountains north of the San Francisco Bay Area and in the Central and Northern Sierra Nevada range. This ten-day storm total is greater than 50 percent of the average annual rainfall in many of these locations. Record stream flows were measured on the Russian, Napa, lower Sacra- mento, American, Consumnes and Mokelumne Rivers. Many reservoirs on these rivers and their trihutaries were completely filled. During the same 10 day period, tide stages in the Sacramento-San Joaquin Delta rose 1.7 feet higher than previously recorded at Rio Vista. Description of Damages The storms caused widespread flood damage from the Oregon border in Northern California to Santa Cruz County along the coast and Fresno County in Central California (see Figure 2). A major levee break occurred on the Yuba River flooding the communi- ties of Linda and Olivehurst. Other levee failures resulted in the flooding of six islands, including the community of Thornton in the Sacramento-San Joaquin Delta. Severe flooding occurred along the Russian and Napa Rivers. As of March 14, 1986, FEMA and the State of California had opened 32 Disaster Application Centers in the declared counties. Approximately 11~356 individuals registered at these centers. The Individual and Family Grant Program had received 3,713 applications for assistance; 5,340 families had applied for temporary housing. The Small Business Administration had issued 5,452 loan applications for home and personal property and 2,567 loan applications for business. Additional regis- trations and applications for disaster assistance were expected. As of March 10, the American Red Cross had opened 74 shelters which served 21,000 persons. They also provided food, clothing and other necessities to 6,500 families. The Red Cross reports 14 deaths and 182 injuries resulted from the storms. 6 Figure 2 .......... .......... ............. ............. ::~M~ \ft}\? :::::;:;:;:;:;:;:;:;:: :;:;:;:::::::;:::;: ::::::;.>,.:-:.;.' .........:-:<............. .................. S H AS T A ::WM#( :;:;:;::;:;:;:;:;: .. DECLARED COUNTIES AS OF MARCH 15, 1986 SAN SAN BERNARDINO RIVERSIDE SAN DIEGO IMPER I Al 7 P.reliminary estimates indicate more than $50 million in damages to public property. Numerous state and local roads were closed due to flooding, heavy snowfall or landslides. Just south of Sacramento, Interstate 5, a major north south corridor in the state was closed for more than a week. Interstate 80 and U.S. 50 were both closed periodically during the storms. State Routes 49 and 99 were closed. Route 49 will probably not be completely open until June. Most of the roads were passable by March 14, but many required repair and restoration. Governmental and Regulatory Structure Local government in California is comprised of cities, counties and special purpose districts. Cities are incorporated entities of local government; counties govern the unincorporated areas of the state not otherwise subject to city, state, or federal laws. For the purposes of this Flood Hazard Mitigation Report, however, the legal status of these separate entities of local government is not significant. Subject to certain restrictions imposed by the State Legislature, counties and incorporated cities have the authority to enact land use and building construction standards consistent with the General Plan adopted by the county or city. Local government has traditionally relied upon urban growth and economic development to increase revenues necessary for providing governmental services. The cost of government has risen markedly in recent years, but revenues have not kept pace. Since the passage of California's Propositions 13 and 4, much of the state is increasing- ly concerned about the costs of public programs and the ability of local governments to provide adequate services based on s1gnifi- cantly reduced resources. California law authorizes the formation of special districts, such as for land reclamation, flood control or other purposes. Special purpose districts are usually single-purpose jurisdictions estab- lished apart from existing local government. Essentially, they function as independent state subdivisions, with a wide variety of organizational structures. 8 PART II DEVELOPMENT OF RECOMMENDATIONS The IHMT reviewed mitigation opportunities for the following flood hazards: (1) inundation of land, structures and facilities; (2) damage caused by levee failure; and (3) damage from high velocity flows. After much discussion, the Team decided it was not possible to formu- late work programs to mitigate all hazards. Therefore, the Team chose a dual focus for this report, resulting in work programs that apply statewide, as well as recommendations for specific locations. The Team also reemphasized recommendations they made in 1982 (FEMA-651-DR-CA) and 1983 (FEMA-677-DR-CA) for areas that sustained repeated flooding. The work programs aLe the recommendations of the IHMT and were agreed upon by the participating members. Each work program includes a work element, a background statement that describes the issue and intent of the Team, a listing of the agencies responsible for the work element, financing, and a work schedule. A major concern of the Team was continued urbanization of areas pro- tected by levees. The following problems were identified: a) Levees that were constructed for agricultural purposes; b) Levee systems that are maintained by more than one agency; c) Levees that were not constructed to current standards. Levees often provide a sense of false security, encouraging develop- ment in possibly unsafe areas. Local governments are frequently pressured to allow additional development in these areas. In addi- tion, many areas such as Linda and Olivehurst in Yuba County are not designated as floodprone by the National Flood Insurance Program (NFIP) because they are protected by project levees. Other locations are not designated as floodprone because the Flood Insurance Study was completed before the current levee policy was used to map flood prone areas. Few local jurisdictions require more stringent building codes than the minimums required by the NFIP. Continuing urbanization will expose ever growing numbers of people to dangerous flooding. Adherence to minimum NFIP standards is no longer sufficient to deter future damages in levee protected areas. Other areas within the declared counties also have significant hazards and mitigation opportunities. They will be addressed by the FEMA and State HMCs as required by Section 406, P.L. 93-288. Section 406 Lequires the State or local governments to evaluate the natural hazards of the areas where Federal disaster loans or grants are used and to take action to mitigate them. 9 Under Section 406, a FEMA and a State HMC were appointed. A. local HHC will be appointed for each jurisdiction that has significant hazards and will work closely with the FEMA and the State HMC to evaluate the impacts of the hazards, evaluate possible measures to mitigate the hazards, and recommend appropriate mitigation measures. The FEMA and State HMCs will meet with local HMCs to explain the work programs in this report and encourage their implementation. Significant hazards have been identified in the following local jurisdictions. CONTRA COSTA COUNTY Contra Costa County SACRAMENTO COUNTY Sacramento County City of Sacramento LAKE COUNTY Lake County City of Lakeport SAN JOAQUIN COUNTY San Joaquin County MARIN COUNTY Marin County City of Corte Madera Town of Fairfax City of Novato Town of Ross Town of San Anselmo SANTA CLARA COUNTY City of Gilroy SANTA CRUZ COUNTY Santa Cruz County NAP A COUNTY Napa County City of Napa City of St. Helena Town of Yountville SOLANO COUNTY Solano County City of Vacaville SONOMA COUNTY Sonoma County City of Petaluma PLACER COUNTY City of Roseville YOLO COUNTY Yolo County YUBA COUNTY Yuba County According to Section 406, the State must submit a Hazard Mitigation Plan by August 21, 1986. The State Plan will use the guidance provided by this IHMT Report as well as issues identified by the FEMA, State and Local HMCs. 10 PARTIIl GENERAL RECOMMENDATIONS 11 URBANIZATION AND STRUCTURAL SOLUTIONS The varied terrain and hydrologic conditions in California, coupled with rapid urban development, has mandated flood protection measures throughout the state. Levees are one of the widely used methods of protection. Levees in California can be generally grouped into three major categories: (1) Project levees, (2) non-project levees within the legal boundaries of the Sacramento-San Joaquin Delta, and (3) other non-project levees which include private levees. Project levees in the State have been constructed under various State and Federal authorizations and are well documented. These levees, which total about 1,760 miles in the Central Valley, are generally in very good condition. They are regularly inspected by the State and maintained by the State and local districts. E~cept for those in the Delta, non-project levees have generally neither been documented nor comprehensively studied. Such levees, which exis t throughout the State, are relied on by many Californians to provide flood protection. All levees provide a false sense of security. Private levees, often inadequately constructed, inspected and maintained, are susceptible to a higher degree of failure than project levees. Without appropriate construction guidelines, periodic inspections, and properly administered maintenance, the level of protection provided to the public is questionable. Experience with project levees has established the soundness of an effective levee management program. The absence of an effective levee management program for non-project levees has often contri- buted to flood losses in excess of what otherwise have occurred. Consequently, general statewide construction, inspection and maint- enance guidelines should be established, and a local non-project levee management plan including financing should be encouraged. WORK ~LEMENT #1: Establish a fact-finding task force to extensively research questions raised by the IHMT regarding reclamation and flood control districts. Background: A numner of questions were raised by the IHMT regarding reclamation and flood control districts and the non-project and private levees within their boundaries. These questions include but are not limited to the follo~ing: a) What is the procedure used to form these districts? b) What is the purpose and function of these districts? c) What are their powers and responsibilities? 12 d) Do they have the authority to assess and to raise revenues? e) Are minimum levee construction, inspection and maintenance standards required? f) Are emergency response plans required and if so, are they coordinated by all agencies? g) Who has oversight authority of these districts? h) What are the powers, duties and responsibilities of over- sight agencies and jurisdictional authorities? Action Agency: Fact finding task force led by FEMA and State DWR including USACE, State OES, and Reclamation Board. Financing: No special funding required. Schedule: 60 days. WORK ELEMENT #2: Recommend changes to: (1) improve non-project and private levee construction, inspection and maintenance performed by reclamation and flood control districts and (2) clarify the relationship between reclamation and flood control districts and other local, state and federal authorities. Background: These recommendations will be based on the facts established in Work Element Ill. Of particular concern to the IHMT are the non-proj ect and private levees which lie within the boundaries of locally formed reclamation and flood control districts. These levees are generally not as well maintained as project levees and have a greater likeli- hood of failure. Consequently, they often provide an inadequate level of protection to residents within these areas. In order to promote effective interaction between local/state/federal authori- ties and reclamation and flood control districts, it is necessary to determine what their authorities are and the extent of their powers, duties and responsibilities. Action Agency: IHMT Financing: No special funding required. Schedule: 60 days after the completion of Work Element #1. 13 WORK ELEMENT 113: Develop a proposal to establish and enforce statewide construction, inspection, and maintenance standards for non-project and private levees. Background: Experience with project levees has established the soundness of an effective levee management program. The lack of an overall state- wide management program for non-project and private levees, however, has often contributed to flood losses in excess of what may other- wise have occurred. Non-project levees make up approximately 80 percent of the levees in the Sacramento-San Joaquin Delta. Action Agency: State DWR as lead agency, with assistance from FEMA, USACE, USBR, SCS, and State OES and Reclamation Board. Financing: Within existing funds. Schedule: 90 days to complete a proposal for submittal to the State Legislature. WORK ELEMENT #4: Implement a statewide construction, inspection, and maintenance program for non-project and private levees, if the assessment of Work Element #3 results in appropriate legislation. Background: Often local agencies are not adequately equipped technically or financially to carry out adequate levee management measures. In April 1984, the Department of Water Resources, in connection with the February 9, 1983, disaster declaration (FEMA-677-DR) issued a report, "Non-Project Levee Hazard Mitigation". The report encouraged develop- ment of a non-project levee protection plan. Action Agency: State DWR with assistance from FEMA, USACE, USBR, SCS, and State OES and Reclamation Board. Financing: Special funding will be required. Schedule: 180 days to implement the program after receipt of legislative authorization to proceed. WORK ELEMENT #5: Encourage local governments to develop and implement a non-project levee management plan. 14 Background: The 1984 State Department of Water Resources Report, "Non-project Levee Hazard Mitigation" and the IHMT Report (FEMA-677-DR-CA) urged the development of a non-project levee management plan as an important component of a community's floodplain management program to prevent flood losses and reduce the impact of flood problems. Action Agency: FEMA and State DWR. Financing: Normal program delivery. Schedule: Immediate and ongoing. 15 FLOODPLAIII MANAGEMENT AND RATIONAL FLOOD INSURANCE PROGRAM A key effort after each flood disaster is to remind communties of the need for proper floodplain management, and to re-emphasize to the public the desirability of flood insurance as a means of offsetting personal losses. A disaster invariably discloses situations involving misinformation about flood insurance, not only among owners of resi- dences and businesses but on the part of insurance agents as well. Hhen <-l community enters the regular phase of the NFIP, they are visited by personnel of the State Department of Water Resources, offering technical assistance on the application of federal regula- tions and administering the community's floodplain management ordinance. This effort is conducted under contract with FEMA. In support of the DWR effort, the disaster provides opportunities to pinpoint communities with special regulations and ordinance problems. This effort has proven from past flood disasters to be an important part of the disaster follow-up. WORK ELEMENT #6: Train insurance agents and lenders in disaster declared counties in their responsibilities under the NFIP. Background: Federal agencies require the purchase of flood insurance as a condi- tion of disaster loans and grants. Therefore, many new flood insur- ance policies will be written during the next few months. Insurance agents in these counties may need additional training. Regular NFlP workshops should be conducted by Computer Sciences Corporation in the disaster declared counties where many policies will be written. Action Agency: FEMA/FIA through CSC. Financing: Normal program delivery. Schedule: Immediate and ongoing. WORK ELEMENT it7: Train insurance agents in writing flood insurance policies in areas where a restudy by FEMA will result in delineation of additional flood hazard zones. Background: FEMA is conducting map restudies in Napa and Sonoma Counties. It is expected that special flood hazard zone designations may change as a result of these restudies. If flood hazard zone designations change, different insurance rates will apply. 16 Action Agency: FEMA/FIA through CSC. Financing: Normal program delivery. Schedule: After the revised FIRM is published. WORK ELEMENT 118: Visit those communities which sustained substantial damage in this disaster to provide assistance to assure compliance with NFIP requirements. Background: In the aftermath of this flood, there will be many requests to rebuild or repair structures in the floodplain. During reconstruc- tion, communities will be required to enforce seldom used provisions of the NFIP. Requirements of the NFIP that should be emphasized before reconstruction are: a) Repairing substantially damaged structures; b) Replacing structures; c) Anchoring structures; d) Use of appropriate construction methods and materials for construction. Note: Mobile homes are considered structures. Action Agencies: FEMA and State DWR. Financing: Normal program activity. Schedule: Immediate and ongoing. WORK ELEMENT 119: Visit those communties which may join the NFIP as a result of the disaster to provide assistance in interpreting the regulations and enforcing their ordinance. Background: Several communities may ]01n the NFIP to qualify for the full range of federal disaster assistance. While these communities will adopt .the necessary standards to join the program, they may not fully understand their responsibilities as floodplain administrators. The Community Assistance Program (California DWR) or Community Coordina- tion Meetings (FEMA) can provide educational assistance to these 17 communities to assist them in interpreting and implementing the NFIP. Action Agency: FEMA and State DWR. Financing: Normal program activity. Schedule: Immediate and ongoing. 18 FLOOD WARNING AND DATA COLLECTION A coordinated system of flood forecasting and warning can lead to a significant reduction in impacts such as loss of life and property damage. Only after recognition of a flood threat can the warning dissemination process begin. In areas of California where stream elevations can rise quickly, advanced warning is imperative. Such advanced warning can be provided quickly and automatically by use of the Automated Local Evaluation in Real Time (ALERT) system. Once a flood has occurred, it is very important to gather as much information as possible concerning the event. In particular, dis- charge and stage data should be collected for affected streams and tributaries. This information, added to historical data, can pro- vide valuable information for forecasting and floodplain management activities. WORK ELEMENT #10: Investigate the feasibility of implementing a local cooperative flood warning system, ALERT, in areas with flood problems associated with rapid cresting streams. Background: In recent years, the National Weather Service (NOAA/NWS) has imple- mented ALERT flood warning systems in many areas of California. A NWS scientist could provide local agencies with substantial support in the areas of design, system software, and assessment of stream conditions. NWS can also assist local governments in compiling elements of a preparedness response plan. The system would be used to trigger appropriate warning to those in identified impact areas. Action Agency: NOAA/NWS, State, county and local governments. Financing: Intergovernmental. Schedule: Immediate and ongoing. WORK ELEMENT #11: Coordinate the gathering of discharge measurements for gaged and ungaged tributaries and streams in the flood impacted areas. Rackground: Many flood studies, especially those on tributaries to the Russian River and Sacramento River are based on regional estimates or very limited local data. Depths of flooding were experienced in C Zones that were in excess of sheet runoff. It is essential to know the average discharge of those streams, as compared with flood discharge. 19 Action Agency: The USGS, with technical support from the SCS, USACE, NOAA, USBR, and State DWR. Financing: USGS, with cooperation from local government and relevant federal agencies. Scheduling: Within 120 days, depending on the number of sites to be studied. 20 P ART IV SITE SPECIFIC IECOHMENDATIONS 21 RUSSIAN RIVER Description of Area The Russian River flows southward into Sonoma County from Lake Mendocino, turns west and flows to the Pacific Ocean at Jenner. The Russian River communities have traditionally been dependent upon recreational uses of the River for an economic base. Permanent residents, a growing segment of these communities, include those who service the tourist industry or work in nearby urban centers. The area is marked by its scenic beauty and small town atmosphere. The Russian River has a long history of damaging floods. Major flood stages, exceeding 46.0 feet, have occurred five times since public records were begun in 1897. Floods in the Russian River basin normally last three or four days. Flooding develops within 24-48 hours after the beginning of a flood-producing storm. How- ever, tributaries rise so rapidly that flooding occurs on some as early as four hours after heavy rainfall begins. Since the completion of the Coyote Dam at Lake Mendocino during the early 1960s, maximum flood stages on the Russian River have been reduced one to two feet. Warm Springs, the $330 million earthfilled dam completed in 1984, further reduced the maximum flood stage of this event an estimated six feet (USACE datum). The river crested at 48.6 feet in Guerneville at 7:00 a.m. on Tuesday, February 18, 1986. All of the flood impacted communities adjacent to the Russian River are unincorporated and within the jurisdiction of Sonoma County. The County is in the regular phase of the NFIP. There are approxi- mately 900 flood insurance policies in the Russian River area, providing coverage of about $34 million of structural and $5.5 million of content coverage. The Disaster Most tributaries and streams in the Russian River Basin were above flood stage with many at or near record levels. Disastrous flooding occurred along the river between Hacienda and Duncan Mills. The State Department of Water Resources maintains a telemetered gage station near Venado (elevation 1,260 feet), ten miles west of Healdsburg. During the period February 12 to February 21, a series of Pacific storms dropped from 14.3 inches to 39.28 inches of rain on the 2,200 square mile Russian River watershed. During this period, 56 percent of the annual rainfall of 70 inches was recorded. On February 17, the USGS measured a peak flow of 69,000 cubic feet per second on the Russian River near Healdsburg, producing a flood stage of 25.8 feet (27.0 feet is the flood of record). 22 At the Hacienda Bridge near Guerneville, peak flows of 91,000 cubic feet per second produced a 48.6 foot flood stage (49.6 feet is the flood of record). Initial flood stage along this reach (Guerneville) is 32.0 feet. Damage in the many small communities adjacent to the Russian River was extensive and severe. Preliminary Red Cross estimates indicated 15-20 homes were destroyed and nearly 1,000 had various levels of damage. Requests for temporary housing at the Guerneville DAC are in excess of 1,000. WORK ELEMENT #12: Determine how to avoid continued Federal investment in high flood risk areas where there is repetitive flooding, structural damage or loss of life. Background: Under the directive of the Office of Management and Budget, the IHMT is to identify "areas in which Federal investment to repair or replace structures and facilities should be avoided and the reloca- tion of people and structures out of these areas should be encouraged. II The IHMT has identified certain areas along the Russian River where Federal investment should be avoided and relocation encouraged. These are areas of repetitive damage, deep flooding and high velocity flows. The IHMT can encourage relocation out of these areas, but certain Federal programs cannot avoid funding of damaged structures. The inability to avoid funding actually encourages occupancy of these known high hazard areas. In all likelihood, these areas will require future disaster assistance. Executive Order 11988 (Appendix C) can be used to avoid Federal investment in high flood risk areas. However, the implementation of Executive Order 11988 varies from one agency to another; for example: a) Some agencies apply the full eight-step process to all agency actions in or affecting the floodplain. b) Some agencies exempt specific actions from the requirements of Executive Order 11988. c) Some agencies have determined that funding below a specified amount is exempt from the requirements of Executive Order 11988. The amounts specified vary from $5,000 to $500,000. d) Some agencies consider that they have met the Executive Order 11988 requirement by requiring the purchase of flood insurance. 23 While certain areas along the Russian River serve as an example of where Federal assistance should be avoided, there are many other locations nationwide where this also applies. The Russian River example is used to illustrate this problem. In addition to consis- tent enforcement of Executive Order 11988, other possible solutions include: a) Enacting legislation, similar to the Coastal Barriers Act or to the proposed legislation concerning the Colorado River; b) Providing more funds for relocation of structures. This issue was also discussed by the IHMT for FEMA-651-DR-CA. See page 16 of that report for details. Action Agency: Hazard Mitigation Task Force, IHMT member agencies, OMB. Financing: To be determined. Schedule: Long-range. WORK ELEMENT #13: FEMA and the State NFIP Coordinator will work closely with the Russian River communities to assure compliance with the NFIP, placing emphasis on the following requirements: a) Repairing substantially damaged structures; b) Replacing structures; c) Using appropriate construction methods and materials. Background: The damaged areas were primarily located within the designated Zone A on the Flood Insurance Rate Maps (FIRM). Older buildings and homes not floodproofed or elevated suffered major damage. As a result of this flood, there will be many requests to rebuild or repair structures in the floodplain and County officials will be required to implement many provisions of the ordinance that are not commonly used. FEMA and the State NFIP Coordinator can assist by working closely with the County and providing information during the recovery and reconstruction period. Requirements of the NFIP that will be particularly important during reconstruction are: a) The County must require that: 1) All new construction and substantial improvements of residential structures in the floodplain have the lowest 24 floor elevated to or above the base flood level; and 2) All new construction and substantial improvements of non- residential structures in the floodplain have the lowest floor elevated or floodproofed to or above the base flood leveL NOTE: "Substantial improvement" is defined as any repair, reconstruction or improvement of a structure, the cost of which exceeds 50 percent of the market value of the structure, either (1) before any improvement or repair is started; or (2) if the structure has been damaged, before the damage occurred. b) The County must review all permit applications to determine whether proposed building sites will be" reasonably safe from flooding. If a proposed building site is in a floodprone area, all new construction and substantial improvements shall: 1) Be designed and adequately anchored to prevent flotation, collapse or lateral movement of the structure; 2) Be constructed with materials and utility equipment resistent to flood damage; and 3) Be constructed by methods and practices that minimize flood damage. For some locations along the Russian River, elevating or flood- proofing of buildings may not be practical. One-hundred-year flood depths are fairly high, requiring elevation to heights that may be impractical (in some locations in excess of 30 feet). In addition, debris flow is an ever-present danger to elevated structures, as elevation was meant to keep out water and not protect against debris impact. Careful engineering analysis by licensed professionals should be completed before a permit is issued. An engineering analysis may conclude that it is not feasible to rebuild or repair buildings on certain sites. Action Agency: FEMA and State NFIP Coordinator. Financing: Existing programs. Schedule: FEMA and State NFIP Coordinators will meet with Sonoma County within 30 days. 25 SACRAMENTO-SAN JOAQUIN DELTA Once again, the fragile levee systems of the Sacramento-San Joaquin Delta were subjected to severe rains, winds, waves and tidal action. Six islands suffered levee damage and inundation during the most recent disaster, bringing the total to 18 islands inundated since 19RO. This is the fifth Presidential disaster declaration and one emergency declaration that have been made in the Delta since 1980. That is an average of one declaration per year. Not including this disaster, FEMA's Federal disaster assistance has amounted to $67.5 million and another $28.6 million under the State Natural Disaster Assistance Act (NDAA) for levee repair work. The IHMT took action in its March 24, 1983, report (FEMA-677-DR) by requesting the Governor of California to provide State leadership and resources to mitigate against future flood disasters in the Delta. Five work elements were contained in the IHMT report that specified short- and long-term work programs. The 1983 IHMT report supported recommendations in recently issued Federal and State reports containing long-term solutions to Delta problems. In compliance with Section 406, a State "Flood Hazard Mitigation Plan for the Sacramento-San Joaquin Delta" was prepared, dated September 15, 1983. With regard to long-term solutions, the State Reclamation Board, in April 1984, indicated its intent to be the non-Federal sponsor for a flood control project, if ever developed and approved. In September 1984 the Director of the Department of Water Resources reported that the State would prefer a comprehensive Federal/State plan for the Delta that would include water transfer, flood control, recreation, and fish and wildlife enhancement. The State Reclamation Board also supported the comprehensive plan. In July 1985 a coordinated planning effort was initiated by the State Department of Water Resources, the Bureau of Reclamation, and the U.S. Army Corps of Engineers which developed a joint study schedule, providing for completion of the feasibility report and environmental impact statement by 1990. Some short-term mitigation actions have taken place since 1983. FEMA, in a letter to the Governor in December 1985, requested a comprehensive updating of the actions taken and any actions recommended, but not yet completed. The State is in the process of providing that response. WORK ELEMENT #14: Make recommendations regarding continued disaster assistance for the Delta, after reviewing the State status report on the implementation of the Hazard Mitigation Plan for the Delta. 26 Background: Work Element #5 of the 1983 IHMT Report, FEMA-677-DR-CA, Supplement No.1, stated that "The Team recommends continued federal disaster assistance in the Delta, if the State and local jurisdictions take the actions recommended in Work Elements #1-4." Work Elements #1-4 from the 1983 IHMT Report are: #1. The State of California should determine what plan of action it will adopt to correct the problems of the Sacramento-San Joaquin Delta. #2. The State of California should determine what level of federal participation it will seek from Congress for its adopted plan of action. and identify the level of State and local funding. #3. The State and appropriate local jurisdictions should develop appropriate legislation to provide standards for upgrading, reconstruction, repair and maintenance of Delta levees. #4. The State and appropriate local jurisdictions should implement a program to upgrade, reconstruct, repair and maintain the Delta levees in accordance with the standards developed pursuant to Work Element #3 above. The State has completed Work Elements #1 and #2 and some actions were taken to implement Work Elements #3 and #4. In complying with all the Work Elements and Section 406, P.L. 93-288, the State published a Hazard Mitigation Plan for the Delta. On December 13, 1985, FEMA requested a status report of the State Hazard Mitigation Plan. The State is in the process of responding. The IHMT will reconvene after the response is submitted to FEMA to make a recommendation regarding continued disaster assistance. Action Agency: IHMT. Financing: Normal Agency budget. Schedule: The IHMT will reconvene within 30 days after the State's response is received. WORK ELEMENT #15: Develop and pursue alternative planning approaches to correct the flooding problems of the Sacramento-San Joaquin Delta. 27 Background: Beneficial uses of the Delta include agriculture, fish and wildlife, recreation, water supply, navigation, transportation and utilities. Federal and State programs to protect various beneficial uses of the Delta are, in some cases, confined to a single agency objective rather than a coordinated interagency objective for Delta protection. The construction of a Federal flood control project offers only one solution to the need for long-term flood protection. It is recommended that other short- and long-term approaches be investigated in conjunc- tion with a long-term project. Some approaches that may be considered are as follows: a) Develop a master plan for the Delta that is approved by all agencies, and ensure that separate projects are consistent with the master plan. b) Determine feasibility of making Delta levees eligible for P.L. 84-99 funding. c) Participate in the USACE Small Flood Control Project Flood Program (Section 205). d) Request flood control project funding via the State Cong- gressional Delegation in lieu of USACE funding. e) Develop a program to receive State and Federal maintenance funds in lieu of emergency funds. f) Seek legislation for developing a Delta user fund for levee maintenance. Potential sources of funding include, but are not limited to, Delta fishing stamp fees, boater registra- tion, State Water Project and Central Valley Project trans- fer maintenance fee, and apportionment of the general fund. g) Expand the 1982 USACE report to consider Delta flood control projects that involve channel widening. as opposed to increasing levee heights. Action Agency: The Interagency Delta Management Committee, including USACE, USBR, State DWR, and other users and beneficiaries. Financing: To be determined. Schedule: Immediate and ongoing. WORK ELEMENT #16: Define Federal interest in the Delta; i.e., each Team member will identify and provide their agency's interests, projects, activities and/or programs in or affecting the Delta and provide this information to the IHMT. 28 Background: To support a coordinated approach in planning and use of the Delta, various interests and users, both compatible and complementary, as well as those that are incompatible and dissimilar, must be identi- fied. As a first step in determining the various interests rep- resented in the Delta, the IHMT member agencies can determine what interest, if any, their respective agencies have in the Delta. This is the same request made to the team members in the IHMT report for FE~1A-677-DR, Supplement #1. However, the need to redefine the Federal interest exists. This determination of interests will be transmitted by the IHMT leader to the Interagency Delta Management Committee for analysis. Action Agency: FEMA HHS DOT USDA ED EPA USACE HUD SBA DOC DOl Financing: None required. Schedule: 30 days. 29 NAPA RIVER Description of Area The cities of Napa, St. Helena and Yountville are located along the Napa River, which is in the western portion of Napa County. Most of the development and urbanization in Napa County has occurred along the Napa River. Flooding in the Napa River Basin is the result of precipitation over the entire Napa River basin for periods in excess of 12 hours. After periods of intense rainfall, maximum river stages can be expected at the following elapsed times: City of St. Helena City of Napa 4 hours 13-14 hours Flooding occurs when the discharge exceeds approximately 7,000 cubic feet per second at St. Helena. Duration of flooding in some places has lasted as long as several weeks due to inadequate drainage of ponded flood water. The duration of flooding within the agricultu- ral area between Oak Knoll Avenue and the City of Napa is normally from one to three days. The Napa River Basin has been subject to frequent flooding, result- ing in severe damage to agriculture and urban development; 20 damaging floods have been recorded since 1~62. Prior floods that have caused great damage .in the Napa River Basin occurred in 1967, 1963, 1952, 1950, 1941 and 1940. The cities of Napa, St. Helena, and Yountville are in the regular phase of the NFIP. There was an excellent comparison between the 100-year floodplain shown on the FIRM and the actual flooding that occurred. There are approximately 296 flood insurance policies in these communities: 261 in Napa, seven in St. Helena, and 28 in Yountville. As a flood protection measure, all developers are required to up- grade channels as far upstream and downstream as is necessary to convey the 100-year flood. As a result of this requirement, improvements have been made in recent years on short sections of Salvadore Creek and American Canyon Creek. Other structural measures have been constructed on Conn Creek, Tulucay Creek and Sheehy Creek. There has been a great deal of controversy during the last 15 years regarding flood control projects in the area. A flood control project was approved by the U.S. Army Corps of Engineers, but voters expressed opposition to the project by referendum in November 1976, and in June 1977 reaffirmed their opposition. 30 The floodplains of the Napa River have been extensively developed. Also, some development exists within the floodway. Pressure for development in both the floodplain and floodway continues. The Disaster From February 16 through February 18, the Napa River Basin received over 14 inche~ of rain. Normal annual rainfall for the Napa Basin is 24 inches. The Napa River crested at 30 feet at 2:00 a.m. on Saturday, February 16. Flood stage on the river is 25 feet. Gaging stations in St. Helena and at Oak Knoll Avenue in the City of Napa show the peak discharge of this flood, compared to the 100-year flood: Station Location 1986 100-Year Flood Peak Discharge St. Helena Avenue Oak Knoll Avenue 13 ,000 cfs 28,000 cfs 11 ,500 cfs 33,000 cfs According to the "Napa Register," the storm left three dead and 27 injured in the Napa River Basin. Approximately 2,500 homes were evacuated, leaving 7,000 evacuees needing shelter. At least 120 businesses were damaged, the majority in the City of Napa. Damage surveys indicate 35 structures are uninhabitable in the City of Napa, 125 in St. Helena and 19 in Yountville. Electricity was shut down for approximately 25,000 people in the Napa River Basin. According to Building Department officials, the Pacific Gas and Electric Company substation was shut down for 30 hours. WORK ELEMENT #17: Encourage the formation of a Regional Planning Agency to develop a Master Plan for the Napa River Basin. Background: A regional agency will have the legal authority and concurrence of all local jurisdictions within the Napa River watershed and reflect floodplain management. Currently, many separate political entities, including federal agenciest the State of California and Solano, as well as Napa, counties and cities, have jurisdiction over land use along the Napa River. Due to poorly defined authorities and rights, insufficient enforcement resources, lack of information, and politi- cal pressures from special interest groups, strong control over land use along the Napa River has not been exercised in the past. Uncoordinated enforcement of regulations regarding building in the floodplain can compound the extent and scope of damages resulting 31 from flooding. Federal NFIP, State and local floodplain management policies exist which regulate development within the Napa River Basin; yet continual and ongoing development is occurring, and development pressure is intensifying. Action Agency: FEMA and State HMCs. Financing: SCS will determine the availability of financing for resource inventory mapping. Schedule: Meet with communities within 90 days. WORK ELEMENT #18: Remind local agencies within the incorporated and unincorporated areas of the Napa River Basin of their obligations under the NFIP. Background: This work element is particularly important in view of the continued development that has occurred within the Napa River floodplain despite recurrent damaging flooding. It is up to the local juris- dictions in the Napa River Basin to decide what specific plans they will adopt to solve their flooding problems. If they do not choose a structural solution, then it is critical that they enforce not only the letter but also the intent of floodplain management. The base level of the floodplain and the runoff must not be increased. Action Agency: FEMA and "State HMCs, and State NFIP Coordinator. Financing: FEMA. Schedule: Meet with the cities within the Napa River Basin within six months. 32 SACRAMENTO COUNTY In the City and County of Sacramento, there are several opportun- ities for mitigation. The area, bordered by the Sacramento and American Rivers, McClellan Air Force Base, and Placer County, is rapidly urbanizing. Existing land use is mixed. Residential sub- divisions are in the southern portion, while farming and rural communities are located in the north. Commercial and industrial facilities also exist; i.e., the Sacramento Metropolitan Airport, Natomas Airport, and the Arco Arena. In the past, the canals and unimproved lands have been able to handle the rainfall and runoff, but urbanization of the area is increasing. With additional urbanization, it can be anticipated that unless major structural improvements are made, significant local flooding will become a regular event. The flooding in Rio Linda is an example of what could happen in other areas, unless appropriate measures are taken. WORK ELEMENT 1119: Reassess the priority of the redesign and reconstruction of the Rio Linda Boulevard crossing of Arcade Creek to determine whether the project can be advanced to construction prior to 1988. Background: The City of Sacramento is developing a Federal Aid Urban Highway Project in Fiscal Year 1988 to reconstruct Rio Linda Boulevard, including raising the grade over Arcade Creek by four feet. Flood- waters left Arcade Creek in two locations: a) Upstream of the levee system near Marysville Boulevard; b) At the opening in the levee at Rio Linda Boulevard. The water then flowed into the residential area. Several hundred houses (500+) were affected by flooding from a few inches to six feet deep. There was little structural damage to the buildings. Action Agency: City of Sacramento. Financing: City of Sacramento through California Department of Transportation. Schedule: Within six months. WORK ELEMENT 1120: Review the Flood Insurance Studies for Sacramento County and the City of Sacramento to determine if the present studies: 33 a) Accounted for high stages in the Sacramento and American Rivers; b) Used the current levee policy of the NFIP. Background: Since this area is rapidly urbanizing, it is essential that the studies reflect high water levels in the rivers and the levee policy. Special attention should be paid to the county area to the east and north of the Sacramento City limits, including, but not limited to, the Rio Linda area. During the 1986 flood, the stage in the American river at the outlet of Natomas East Main Drain was higher than the 100-year flood level in the Rio Linda area. Water backed directly into that area from the American River. The water level stage in the Sacramento River may control the stage in the American River. Action Agency: FEMA. Financing: FEMA. Schedule: Within one year. WORK ELEMENT f/21: Support Sacramento County in exceeding the m1n1mum requirements of the NFIP by using local flood elevation data based on future development. Background: Sacramento County entered the regular phase of the NFIP March 15, 1979. Prior to that time, minimum elevations for new construction had been based on the Sacramento County Master Plan, developed with the 1962 County hydrological study. These elevations were three feet above the ten-year storm and one foot above the FEMA 100-year flood. FEMA Flood Maps (FIRM) do not reflect projected development pressures throughout the various watersheds. Sacramento County has the expertise to develop flood elevations reflecting full upstream development consistent with the Long-Range Countywide Master Plan. These County-generated elevations for new construction would be an addition to the minimum requirements of the NFIP. The IHMT supports the County's efforts. Action Agency: IHMT. Financing: None. Schedule: Completed. 34 WORK ELEMENT #22: Investigate the feasibility of FEMA authenticating maps produced by the local community which depict full development of watersheds. Background: The IHMT recognizes the need for mapping based on existing condi- tions to determine flood insurance rates. However, local govern- ments need support at the federal level to adopt floodplain manage- ment standards which exceed the federal minimums. It is essential that local governments have support for the enforcement of higher, more realistic floodplain management requirements. Action Agency: Local community with support of FEMA/FIA. Financing: Local. Schedule: As soon as feasible. 35 Geologist before a permit for new or reconstruction will be issued, probably resulted in fewer losses. WORK ELEMENT #23: Continue follow-up on past IHMT recommendations and Section 406 Plan for the City of petaluma, the Corte Madera Creek area of Marin County and the San Lorenzo Valley of Santa Cruz County. Background: It is important to re-emphasize past IHMT recommendations in areas that were previously addressed by the Team (FEMA-651-DR-CA and FEMA- 677-DR-CA). The Federal and State HMCs will meet with the local jurisdictions to encourage continued progress in implementing the past recommendations. Action Agency: IHMT Leader, State HMC. Financing: Normal program delivery. Schedule: Contact communities within 30 days. 37 P ART V PAST RECOMMENDATIONS There was damage in some areas that also sustained damage in 1982. These areas are the City of Petaluma, the Corte Madera Creek area of Marin County and the San Lorenzo Valley in Santa Cruz County. The flooding problems and mitigation opportunities in these locations are described in the 1982 IHMT Report (FEMA-651-DR-CA). Petaluma Recurrent flooding occurs along the Petaluma River, which flows through the center of the City and empties into the San Pablo Bay. The greatest amount of flooding occurs at the confluence of the Petaluma River and Washington Creek, adjacent to the Linda del Mar housing development. The recent rainstorm did not result in as much flooding in the area as occurred in 1982. Work Elements #48-51 of the IHMT Report have been implemented. Progress is underway to implement Work Element #52. According to the City Engineer, the City has relocated four homes and has contracts for relocating three more this Spring. Corte Madera Creek Corte Madera Creek originates in the watershed above Fairfax, passes through San Anselmo and Ross, then empties into the San Francisco Bay at Larkspur. The recent rainstorm did not result in as much flooding in the areas as in the 1982 flood. Work Elements #26-28 of the IHMT Report have been implemented. Significant progress has been made in implementing Work Element #25, completion of the U.S. Army Corps of Engineers' project. FEMA requested a status report of the mitigation measures identified in the IHMT Report in January 1986. San Lorenzo Valley . The San Lorenzo Valley and basin experienced flooding and slope failure along many of the tributaries to the San Lorenzo River during the storms of February 1986. However, the scope and extent of damage was not nearly as severe as that suffered in January 1982 and January/February 1983. A combination of factors were respon- sible for this lower level of damage. Rains during the 1986 flooding did not reach the magnitude of the previous events. Santa Cruz County has adopted many of the IHMT recommendations formulated for 65l-DR and 677-DR and continues to implement others as staff and funding allow. This, combined with a permit program that requires a site-specific geological inspection by the County 36 APPENDIX A REQUIREMENTS OF SECTION 406, P.L. 93-288 Section 406 of Public Law 93-288 requires, as a condition to receiv- ing federal disaster aid, that repairs be done in accordance with applicable codes, specifications and standards. It also requires the State or local government recipients of this aid to evaluate the natural hazards of the area in which the aid is to be used and, if appropriate, take action to mitigate the hazards. A major product of the Section 406 process is a State Hazard Mitigation Plan which describes State and local actions that have and will be taken to mitigate the hazards. Under Section 406, the Federal Emergency Management Agency (FEMA), encourages State and local governments to develop and maintain a systematic program to identify hazards, monitor changes in hazard vulnerability and develop and implement measures for reducing hazard vulnerability. Section 406 is best viewed as a dynamic ongoing process in which disaster declarations become opportunities to review and update existing hazard mitigation plans, rather than isolated events which result in completely new and independent plans. To implement Section 406, a Federal and a State Hazard Mitigation Coordinator (HMC) are appointed. Selected local jurisdictions also designate local HMCs. The Federal, State and local HMCs form survey/planning teams, who accomplish the following: a) Identify areas of significant hazards; b) Visit sites of significant hazard and evaluate impacts; c) Identify areas of damage that would require reconstruction to the standards of the National Flood Insurance Program (NFIP) or to State or local regulation; d) Review and evaluate applicable land use regulations, construction standards and other hazard mitigation measures; e) Review and evaluate existing emergency plans, including warning and evacuation plans; f) Review and evaluate existing hazard mitigation plans; g) Review other pertinent information, such as urban renewal, rehabilitation or master plans; h) Identify and evaluate measures to mitigate the disaster impacts; i) Recommend appropriate hazard mitigation measures; j) Coordinate and take actions necessary to implement the recommendations. The survey/planning team prepares a report on its activities and recommendations and submits it to the FEMA Regional Director and the Governor's Authorized Representative. The State HMC then prepares the State Hazard Mitigation Plan and submits it to the FEMA Regional Director within 180 days from the disaster declaration date. This plan must: a) Analyze the natural hazards in the disaster declared area; b) Analyze existing State and local laws, regulations and programs that pertain to hazard mitigation; c) Identify the strengths and weaknesses in existing State and local programs; d) Propose mitigation measures. The final element in the Section 406 process is to track and monitor the implementation of the State Hazard Mitigation Plan. A-2 APPENDIX B u.s. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL WEATHER SERVICE FORECAST OFFICE 660 PRICE AVENUE REDWOOD CITY, CA 94063 March 6, 1986 Synoptic Situation - Storm Series of February 12-21, 1986 Preceding the storm, the western Pacific Ocean area was charac- terized by a significant influx of cold air from Asia that resulted in the strengthening and southward displacement of a very strong zonal flow between 30N and 40N. During February 10-l3, the strong westerlies continued to shift further southward with the axis of the zonal flow moving to 30N. This pattern was generally sustained through February 22. Over the eastern Pacific, the pre-storm pattern had the very strong low latitude westerlies extending from the western Pacific, between 30N and 40N, to l45W where the main flow was diverted northward into Alaska around a Gulf of Alaska blocking high. A ridge extended from the high southward along 130W off the California coast. By February 12, the Gulf of Alaska blocking high had shifted northward to near 60N with the result that the strong Pacific westerlies were breaking through under the block towards the west coast between 30 and 40N. The trajectory of the unstable air across the entire Pacific Ocean, at relatively low latitudes over warm water, insured that the air was saturated through a very deep layer. This pattern of very moist unstable air over California persisted through February 21. East of 140W, where the zonal flow across the Pacific turned to more west-southwesterly, the moisture surges periodically organized into frontal bands as they repeatedly moved into California with extended periods of moderate or greater precipi- tation. Several times during the rainy episode, tropical air from the vicinity of Hawaii would become entrained in the very strong low latitude westerlies resulting in a strong frontal zone extending from near Hawaii into California, thus the 'pineapple connection' that usually causes heavy, warm rain in California. By February 20, an upper low was evident in the eastern Gulf of Alaska and a ridging trend was showing in the westerlies along 150W. These features were causing a weakening of the flow into California and a turning from southwesterly to westerly. As the offshore ridge continued to develop on February 21 along 140W, the rainy period in California came to an end. The moist flow and rainfall were shifted northward into the Pacific Northwest where more flooding resulted. ~~"'MO"""~'c ~J'. ,.. ~ i~~ Q > '1 ~ ~ '" ,J"Oo,t': ~<.,; ~1fr"'fNT Of c~ u.s. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL WEATHER SERVICE FORECAST OFFICE 660 PRICE AVENUE REDWOOD CITY, CA 94063 March 7, 1986 FLASH FLOODING - NORTHERN CALIFORNIA - FEBRUARY 12-19, 1986 By Monday, February lO, the strong possibility for a major storm later in the week was recognized as the synoptic situation looked very much like that which occurred during the 12/64 flood disaster in northern California. On Tuesday, February ll, mention was made in special weather statements of the severity of the approaching storm. Light rain began to fall over northwest California Tuesday morning and spread to the Bay Area by after- noon. Heavy rain was forecast to spread over the state by Wednesday. Heavy rain did fall over all of northern California Wednesday. The first flash flood watch of the storm period was issued that morning for the areas which had been burned in the previous summer's fires on the central California coast. The first flash flood warning was issued for some of these same areas that evening as very heavy rain fell in the central California coastal mountains. Though precipitation was widespread and heavy this first day, flash flooding. was not a problem outside the burn areas as conditions had been fairly dry for the past few weeks. The rain ended briefly by early Thursday. However, another strong Pacific storm was already bearing down on the state. A watch was issued Thursday morning for all of the central Califor- nia coastal ranges for Thursday night through Friday morning. By Thursday evening, heavy rain began to fall over all of northern and central California. It continued through the night and did not let up until Friday evening, with the heaviest occurring Friday morning. By Friday morning, flash flooding was occurring in the North Bay counties of Marin, Napa and Sonoma, with warnings issued through the afternoon. The watch area was extended to include much of coastal northern and central Califor- nia by Friday afternoon. Warnings had to be issued for most of the counties in this watch area Friday afternoon and evening. At noon, Friday, the NWS and USGS jointly issued a special weather statement advising of the possibility of debris flows and mud slides throughout the Bay Region for the next few days. This advisory remained in effect through the end of the storm period on February 19. By late Friday, the storm was tracking from the Bay Area north- ward and the watch was cancelled for the coastal mountains (burn areas) to the south of the Bay, but it continued in effect for counties north of San Francisco. By Saturday morning the ~~q,~~ d' ." ~ B-2 (.~ G."r ~ o,:~NTOfcd<''# had ended at most low elevation stations, but there ~as still a strong threat of heavy rain for the next few days as the jet stream continued to direct heavy rains toward California. The watch was cancelled Saturday afternoon for all areas, as only showers persisted through Sunday morning. By Sunday morning, February 16, another large storm system was moving onto the coast. Throughout the day counties were added to the watch area. By 9:00 PM, Sunday, most of northern California was under a watch through Tuesday, February 18. As the heavy rain moved through the area, warnings were issued for all counties in the watch area during the period from Sunday after- noon through Tuesday night. By Monday afternoon, February 17, widespread flooding, flash flooding and earth movement was occurring throughout northern California. The very slow moving, heavy subtropical rainfall progressed from the north and west gradually to the south and east. The heaviest precipitation occurred roughly 200 miles north and 100 miles south of a line from San Francisco to Sacramento to Lake Tahoe. At the height of the storm on Monday, the band of rain forecast to enter California stretched from California southwestward to the subtropics near Hawaii. The rain finally slackened in the west on Tuesday morning, but heavy rain and snow continued at the higher elevations in the Sierra with warnings in effect there and watches elsewhere. The next heavy band of precipitation moved onto the coast Tuesday afternoon with watches extended through Wednesday and warnings again posted for the Bay Region, lower Sacramento Valley and Northern Sierra through Wednesday morning. By Wednesday afternoon, February 19, the major portion of the storm had moved east. Though showers continued into the evening, it looked hopeful that the storm was over and w tches were cancelled. However, many rivers and streams in the region were above flood stage with many at record, or near record, levels. Disastrous flooding was occurring or beginning to subside on the North Coast, North Bay, Sacramento and San Joaquin basins (see river stage data for more information). On February 20, record tide stages were set in the Sacramento Delta, putting the entire Delta region in jeopardy of flooding due to record inflows (approximately 650,000cfs) from the Sacramento Basin. These inflows raised the predicted tide level along the Sacramento River by at least 4 feet. The record flows on all the rivers in the Sacramento and San Joaquin Basins put incredible strain on all levees and many failures occurred, causing thousands to evacuate. The most notable levee failure occurred in the Linda/Olivehurst area south of Marysvil1e/Yuba City where the entire population of these towns had to evacuate. B-3 S2cramerlto Basin: Shinoletown 10.9811 Shasta Dam lq~70 r~ed Bluff ':.U/ LhlCO 8.54 Paradise 18.86 S~C,f-amento 9.62 vacaville 13.43 Ir3V1S AFB 9.60 - _. kUS~.lan ba.Sln: ~J:~llit.s 19.20 V~nado 39.28 Santa Rosa 14.30 NaDa. t:aSln: AnONln 26.09 Whsoering Pns 29.51 Nand 1.). \)0 ~.F ,j;<.v Basins: ~:.:f?nt f i el d L.-3iJunitas Lk 25.48 23.47 ~3E;n Francisco ..., ,i:;' ! . ! .J lj.~.n Jose FeltDn b. 1.':;, 18.00 Amerlcan River Basin: Pacific House 25.98 Blue Canyon 34.25 Storm Totals (by Basin) 2/12/86 - 2/21/86 Feather Basin: Bucks Lake 55.72H Fout- Trees La Porte Strawberry DeSalba Canyon Dam Bucks Creek Oroville Dam 52.68 39.64 Vly 35.64 22.13 14.47 24.13 11.24 San Joaquin Valley Basins: Calaveras SF' 33.15 Yosemite NP 21.72 Huntington Lk 19.90 Merced L.b~ Fresno 3.37 Bakersfield .67 Glennville 4.34 Salinas River Basin: ~1ining Ridge Santa Margarta 15.36 Salinas Paso Robles 29.33 'i '7"" .i... ..:..:" 5.32 North Coast Basins: Honeydew 25.50 Gasquet 17.50 Eureka 7.90 Miranda 15.30 B-4 APPENDIX C Executive Order 11988 May 24, 1977 FLOODPLAIN MANAGEMENT By virtue of the authority vestea in me by the Constitution and statutes of the United states of America, and as President of the United States of ~erica, in furtherance of the National Environmental Policy Act of 1969, as amended (42 U.S.C. 4321 et seq.) , the National Flood Insurance Act of 1968, as amended (42 U.S.c. 4001 !! seq.) , and the Flood Disaster Protection Act of 1973 (Public Law 93-234, 81 Stat. 915), in order to avoid to the extent: possible the long and short term adverse impacts associatE!"\ with t~e occupancy and modification of flood- plains and to avoid direct or indirect support of floodplain development wherever there is a practicable alternative, it is hereby ordered as follows: Section 1. Each agency shall provide leadership and shall take action to reduce the risk of flood loss, to minimize the impact of floods on human safety, health and welfare, and to restore and preserve the natural and beneficial values served by floodplains in carrying out its responsibilit~es for (1) acquiring, managing, and disposing of Federal lands and facilities; (2) providi~g Federally undertaken, finance~, or assisted construction and improve- ments: and (3) conducting Federal activities and programs affecting land use, including but not limiteq to water and related land resources planning, regulating, and licensing activities. Sec. 2. In carrying out the activities described in Section 1 of this Order, each agency has a responsibility to evaluate the potential effects of any actions it may take in a floodplain; to ensure that its planning programs and budget requests reflect consideration of flood hazards and FEDI!RAL REGISTI!R, VOL. 42, NO. 101-WI!DNE5DAY, MAY 25, 1977 THE 'IESIDENT floodplain management; and to prescribe procedures to implement the policies and requirements of this Order, as follows: (a) (1) Before taking an action, each agency shall determine w~ether the proposed action will occur in a floodF;ain -- for major Federal actions significantly affecting the quality of the human environment, the evaluation required below will be included in any statement prepared under Section 102(2) (C) of the National Environ- mental Policy Act. This determination shall be made according to a Department of Housing and Urban Development (HUD) floodplain map or a more detailed map of an area, if available. If such maps are not available, the agency shall make a determination of the location of the floodplain based on the best available information. The Water Resources Council shall issue guidance on this information not later than October 1, 1977. (2) If an agency has determined to, or proposes to, conduct, support, or allow a" action to be locaTed in a floodplain, the agency shall consider alternatives to avoid adverse effects and incompatible development in the flood- plains. If the head of the agency finds that the only practicable alternative consistent with the law and with the policy set forth in this Order requires-siting in a floodplain, the agency shall, prior to taking action, (i) design or modify its action in order to minimize potential harm to or within the floodplain, consistent with regulations issued in accord with Section 2(d) of this Order, and (ii) prepare and circulate a notice containing an explanation of why the action is proposed to be located in the floodplain. fEDERAL REGISTEI, VOL. 42, NO. 101-WEDNESOAY, MAY 25, 1.77- C-2 THE PIESIDENT (3) For programs subject to ~~e Office of Management and Budget Circular A-95, the agency shall se~d the notice, not to exceed three pages in length including a location map, to the state and areawide A-95 clearinghouses for the geographic areas affected. The notice -shall include: (i) the reasons why the action is proposed to be located in a floodplain; (iil a statement indicating whether the action conforms to applicable state or local floodplain protection standards and (iii) a list of the alternatives considered. Agencies shall endeavor to allow a brief comment period prior to taking any action. (4) Each agency shall also provide opportunity for early public review of any plans or proposals for actions in floodplains, in accordance with Section 2(blof Executive Order No. 11514, as amended, including the development of procedures to accomplish this objective for Federal actions whose impact is not significant enough to require the preparation of an environmental impact statement under Section 102(2) (C) of the National Environmental Policy Act of 1969, as amended. (b) Any requests for new authorizations or appropriations transmitted to the Office of Management and Budget shall indicate, if an action to be proposed will be located in a floodplain, whether the proposed action is in accord with this Order. (c) Each agency shall take floodplain management into account when formulating or evaluating any water and land use plans and shall require land and water resources use appropriate to the degree of hazard involved. Agencies shall include adequate provision for the evaluation and consideration of flood hazards in the regulations and operating procedures for the licenses, permits, loan or grants-in-aid programs that they administer. Agencies FEDERAL REGlmR, VOL. 42, NO. IOI-WEDNESDAY, MAY 25, 1977 r-< 1"_ ...uaUItNl shall also encourage and provide appropriate guidance to applicants to evaluate the effects of their proposals in floodplains prior to submitting applications for Federal licenses, permits, loans or grants. (d) As allowed by law, each agency shall issue or amend existing regulations and procedures within one year to comply with this Order. These procedures shall incorporate the Unified National Program for Floodplain Management of the Water Resources Council, and shall explain the means that the agency will employ to pursue the nonhazardous use of riverine, coastal and other floodplains in connection with the activities under its authority. To the extent possible, existing processes, such as those of the Council on Environmental Quality and the Water Resources Council, shall be utilized to fulfill the requirements of this Order. Agencies shall prepare their procedures in consultation with the Water Resources Council, the Federal Insurance Administration, and the Council on Environmental Quality, and shall update such procedures as necessary. Sec. 3. In addition to the requirements of Section 2, agencies with responsibilities for Federal real property and facilities shall take the following measures: (a) The requlations and procedures established under Section 2Cd) of this Order shall, at a minimum, require the construction of Federal structures and facilities to be in accordance with the standards and . criteria and to be consistent with the intent of those . promulqated under the National Flood Insurance Proaram. They shall deviate only to the extent that the standards of the Flood Insurance Program are demonstrably inappro- priale for a given type of structure or facility. (b) If, after compliance with the requirements of this Order, new construction of structures or fEDUAL REGISTEI, VOL. 42, NO. lOl-WEDNESDAY, MAY 25, 1977 C-4 tH!! ~INT facilities are to be located in a floodplain;;aecepted floodproofing and other flood protection measures shall be applied to new construction or rehabilitation. To a~hieve flooO protection, agencies shall, wherever practicable, elevate structures above the base flood level rather than filling in land. (c) If property used by the general public has suffered flood damage or is located in an identified flood hazard area, the responsible agency shall provide on structures, and other places where appropriate, con- spicuous delineat10n of past and probable flood height in order to enhance public awareness of and knowledge about flood hazards. (d) When property in floodplains is proposed for lease, easement, right-of-way, or disposal to non-Federal public or private parties, the Federal agency shall (1) reference in the conveyance those uses that are restricted under identified Federal, State or local floodplain regulations; and (2) attach other appropriate restrictions to the uses of properties by the grantee or purchaser and any successors, except where prohibited by law; or (3) withhold such properties from conveyance. Sec. 4. In addition to any responsibilities under this Order and Sections 202 and 205 of the Flood Disaster Protection Act of 1973, as am~nded (42 O.S.C. 4106 and 4128), agencies which guarantee, approve, regulate, or insure any financial transaction which is related to an area located in a floodplain shall, prior to completing action on such transaction, inform any private parties participating in the transaction of the hazards of locating structures in the flOOdplain. PlDIIAL IIOISTD, VOl.. 42, NO. 101-WlDNlSDAY, MAY IS, 1"., THE PRESIDENT Sec. 5. The head of each agency shall submit a report to the Council on Environmental Quality and to the Watex Resources Council on June 30, 1978, regarding the statu~ of their procedures and the impact of this Order on the agency's operations. Thereafter, the Water Resources Council shall periodically evaluate agency procedures and their effectiveness. Sec. 6. As used in this Order: (a) The term "agency" shall have the same meaning as the term "Executive agency" in Section 105 of Title 5 of the United States Code and shall include the military departments; the directives contained in this Order, however, are meant to apply only to those Agencies which perform the activities described in Section 1 which are located in or affecting floodplains. (b) The term "base flood" shall mean that flood which has a one percent or greater chance of occurrence in any given year. (c) The term "floodplain" shall mean the lowland and relatively flat areas adjoining inland and coastal waters including floodprone areas of offshore islands, including at a minimum, that area subject to a one percent or greater chance of flooding in any given year. Sec. 7. Executive Order No. 11296 of August 10, 1966, is hereby revoked. All actions, procedures, and issuances taken under that Order and still in effect shall remain in effect until modified by appropriate authority under the terms of this Order. Sec. 8. Nothing in this Order shall apply to assistance provided for emergency work essential to save lives and protect property and public health and safety, performed pursuant to Sections 305 and 306 of the Disaster Relief Act of 1974 (88 Stat. 148, 42 V.S.C. 5145 and 5146). FEDERAL REGISTER, VOL. 42, NO. 101-WEDNESDAY, MAY 2s:--n77 l.-h THE PRESIDENT Sec. 9. To the extent the provisions of Section 2(a) of this Order are applicable to projects covered by Section l04(h) of the Housing and Community Development Act of 1974,. as amended (88 Stat. 640, 42 U.S.C. 5304(h)), the responsibilities under those provisions may be assumed by the appropriate applicant, if the applicant has also assumed, with respect to such projects, all of the respon- sibilities for environmental review, decisionmaking, and action pursuant to the National Environmental Policy Act of 1969, as amended. tlL --. J -...J/h?7 THE WHITE HOUSE, May 24, 1977 [FR Doc.77-15121 Filed 5-24-77;1: 42 pm] FEDERAL REGISTEI, YOLo 42. NO. 101-WEONESDAY. MAY 25. 1977 C-7