Chapter 4 Risk Assessment

Requirement §201.6(c)(2): [The plan shall include] A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards.

As defined by the Federal Emergency Management Agency (FEMA), risk is a combination of hazard, vulnerability, and exposure. “It is the impact that a hazard would have on people, services, facilities, and structures in a community and refers to the likelihood of a hazard event resulting in an adverse condition that causes injury or damage.”

The risk assessment process identifies and profiles relevant hazards and assesses the exposure of lives, property, and infrastructure to these hazards. The process allows for a better understanding of a community’s potential risk to natural hazards and provides a framework for developing and prioritizing mitigation actions to reduce risk from future hazard events.

This risk assessment followed the methodology described in the FEMA publication Understanding Your Risks—Identifying Hazards and Estimating Losses (FEMA 386-2, 2002), which breaks the assessment down to a four-step process:

1. Identify Hazards; 2. Profile Hazard Events; 3. Inventory Assets; and 4. Estimate Losses.

Data collected through this process has been incorporated into the following sections of this chapter:

➢ Section 4.1: Hazard Identification identifies the hazards that threaten the planning area and describes why some hazards have been omitted from further consideration. ➢ Section 4.2: Hazard Profiles discusses the threat and impacts to the planning area and describes previous occurrences of hazard events and the likelihood of future occurrences. ➢ Section 4.3: Vulnerability Assessment assesses the planning areas’ exposure to natural hazards; considering assets at risk, critical facilities, future development trends, and, where possible, estimates potential hazard losses. ➢ Section 4.4: Capability Assessment inventories existing mitigation activities and policies, regulations, plans, and projects that pertain to mitigation and can affect net vulnerability.

This risk assessment covers the entire geographical extent of unincorporated Lake County (i.e., the Lake County Planning Area). And as required by FEMA, this risk assessment for the Lake County Planning Area also includes an evaluation of how the hazards and risks vary across the Planning Area.

Lake County Public Review Draft 4-1 Local Hazard Mitigation Plan Update January 2018 This LHMP Update involved a comprehensive review and update of each section of the 2012 risk assessment. As part of the risk assessment update, new data was used, where available, and new analyses were conducted. Where data from existing studies and reports was used, the source is referenced throughout this risk assessment. Refinements, changes, and new methodologies used in the development of this risk assessment update are summarized in Chapter 2 What’s New and also detailed in this risk assessment portion of the plan. 4.1 Hazard Identification

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type…of all natural hazards that can affect the jurisdiction.

The Lake County Hazard Mitigation Planning Committee (HMPC) conducted a hazard identification study to determine the hazards that threaten the Planning Area. This section details the methodology and results of this effort.

Data Sources

The following data sources were used for this Hazard Identification portion of the plan:

➢ HMPC input ➢ National Climatic Data Center Storm Events Database ➢ 2012 Lake County Hazard Mitigation Plan ➢ 2013 State of California Hazard Mitigation Plan ➢ 2017 Draft Lake County Emergency Operations Plan ➢ FEMA Disaster Declaration Database

4.1.1. Results and Methodology

Using existing hazards data and input gained through planning meetings, the HMPC agreed upon a list of hazards that could affect Lake County. Hazards data from the California Office of Emergency Services (Cal OES), FEMA, California Department of Water Resources, the National Oceanic and Atmospheric Administration (NOAA), and many other sources were examined to assess the significance of these hazards to the Planning Area. Significance was measured in general terms and focused on key criteria such as frequency and resulting damage, which includes deaths and injuries, as well as property and economic damage. The natural hazards evaluated as part of this plan include those that have occurred historically or have the potential to cause significant human and/or monetary losses in the future. Only the more significant (or priority) hazards have a more detailed hazard profile and are analyzed further in Section 4.3 Vulnerability Assessment.

The following hazards in Table 4-1, listed alphabetically, were identified and investigated for this LHMP Update. As a starting point, the 2013 California State Hazard Mitigation Plan was consulted to evaluate the applicability of new hazards of concern to the State to the Planning Area. Building upon this effort, hazards from the past plan were also identified, and comments explain how hazards were updated from the previous plan. Most hazards from the 2012 plan were profiled in this Plan Update. Some hazards were

Lake County Public Review Draft 4-2 Local Hazard Mitigation Plan Update January 2018 reclassified and added to: water shortage was added to the drought hazard, quagga mussels were added with cyanobacterial bloom in as aquatic biological hazard, and geothermal gas release was expanded in the volcano hazard. New hazards include agricultural hazards, climate change, hazardous materials transportation, and subsidence.

Table 4-1 Lake County Hazard Identification and Comparison

2017 Hazards 2012 Hazards Comment Agricultural Hazards – New hazard. Aquatic Biologic Hazards: Cyanobacterial Greater analysis was performed based on monitoring cyanobacterial bloom bloom data from the County. Aquatic Biologic Hazards: quagga – New hazard mussel Climate Change – New hazard. Dam Failure Dam Failures Dam inundation analysis was performed. Drought and Water Shortage Drought The water shortage discussion was added. Additional vulnerability discussion was added. Earthquake Earthquake A Hazus analysis was performed to add to the vulnerability discussion. Flood: 1%/0.2% Annual Chance Floods DFIRM flood analysis was performed. Assets at risk, populations at risk, and critical facilities at risk to flooding were analyzed. Flood: Localized/Stormwater Localized Flooding Additional discussions of specific areas of localized flooding were discussed. Hazardous Materials Transportation – New hazard. Landslide and Debris Flows Landslides A greater analysis was performed using GIS. Values at risk, populations at risk, and critical facilities were analyzed. Levee Failure Levee Failure (as The hazard was broken out from the flood hazard and part of flood) a larger discussion of levee failure in the County was added. Severe Extreme Heat – New hazard. Severe Weather: Heavy Rains, Snow, Severe Storms Similar analysis was performed. and Storms (winds, hail, lightning) Subsidence – New hazard. Volcano Volcano Eruption/ Additional discussions regarding vulnerability were Geothermal Gas added. Included additional information on the Release Geothermal Gas hazard. Wildfire Fire Additional analysis was performed on the fire hazard severity zone layer. Assets at risk, populations at risk, and critical facilities at risk to wildfire were analyzed.

Lake County Public Review Draft 4-3 Local Hazard Mitigation Plan Update January 2018 Table 4-2 was completed by the County and HMPC to identify, profile, and rate the significance of identified hazards. Only the more significant (or priority) hazards have a more detailed hazard profile and are analyzed further in Section 4.3 Vulnerability Assessment. Table 4-35 in Section 4.2.20 Natural Hazards Summary provides an overview of these significant hazards.

Lake County Public Review Draft 4-4 Local Hazard Mitigation Plan Update January 2018 Table 4-2 Lake County Hazard Identification

Probability of Climate Geographic Future Magnitude/ Change Hazard Extent Occurrences Severity Significance Influence Agricultural Hazards Significant Highly Likely Limited High Medium Aquatic Biological Hazards: Significant Highly Likely Limited High High cyanobacterial bloom Aquatic Biological Hazards: quagga Significant Likely Critical High High mussel Climate Change Extensive Likely Limited High – Dam Failure Limited Occasional Limited High Low Drought and Water Shortage Extensive Likely Critical High Medium Earthquake Extensive Likely Critical High Low Flood: 1%/0.2% Annual Chance Limited Occasional/Unlikely Limited High Medium Flood: Localized/Stormwater Limited Likely Limited Medium Medium Hazardous Materials Transport Limited Likely Limited Medium Low Landslide and Debris Flows Significant Likely Limited Medium Medium Levee Failure Significant Likely Limited Medium Medium Severe Weather: Extreme Heat Significant Likely Critical Medium Medium Severe Weather: Heavy Rains, Snow, Significant Highly Likely Critical High High and Storms Severe Weather: High Winds Significant Likely Critical High Low Subsidence Limited Occasional Limited Low Low Volcano Significant Unlikely Critical High Low Wildfire Significant Highly Likely Critical High High Geographic Extent Magnitude/Severity Limited: Less than 10% of planning Catastrophic—More than 50 percent of property severely damaged; shutdown of area facilities for more than 30 days; and/or multiple deaths Significant: 10-50% of planning area Critical—25-50 percent of property severely damaged; shutdown of facilities for at Extensive: 50-100% of planning least two weeks; and/or injuries and/or illnesses result in permanent disability area Limited—10-25 percent of property severely damaged; shutdown of facilities for Probability of Future more than a week; and/or injuries/illnesses treatable do not result in permanent Occurrences disability Highly Likely: Near 100% chance of Negligible—Less than 10 percent of property severely damaged, shutdown of occurrence in next year, or happens facilities and services for less than 24 hours; and/or injuries/illnesses treatable every year. with first aid Likely: Between 10 and 100% Significance chance of occurrence in next year, Low: minimal potential impact or has a recurrence interval of 10 Medium: moderate potential impact years or less. High: widespread potential impact Occasional: Between 1 and 10% Climate Change Impact: chance of occurrence in the next Low: Climate change is not likely to increase the probability of this hazard. year, or has a recurrence interval of Medium: Climate change is likely to increase the probability of this hazard. 11 to 100 years. High: Climate change is very likely to increase the probability of this hazard. Unlikely: Less than 1% chance of occurrence in next 100 years, or has a recurrence interval of greater than every 100 years.

Lake County Public Review Draft 4-5 Local Hazard Mitigation Plan Update January 2018 4.1.2. Disaster Declaration History

One method the HMPC used to identify hazards was the researching of past events that triggered federal and/or state emergency or disaster declarations in the Planning Area. Federal and/or state disaster declarations may be granted when the severity and magnitude of an event surpasses the ability of the local government to respond and recover. Disaster assistance is supplemental and sequential. When the local government’s capacity has been surpassed, a state disaster declaration may be issued, allowing for the provision of state assistance. Should the disaster be so severe that both the local and state governments’ capacities are exceeded, a federal emergency or disaster declaration may be issued allowing for the provision of federal assistance.

The federal government may issue a disaster declaration through FEMA, the U.S. Department of Agriculture (USDA), and/or the Small Business Administration (SBA). FEMA also issues emergency declarations, which are more limited in scope and without the long-term federal recovery programs of major disaster declarations. The quantity and types of damage are the determining factors.

A USDA declaration will result in the implementation of the Emergency Loan Program through the Farm Services Agency. This program enables eligible farmers and ranchers in the affected county as well as contiguous counties to apply for low interest loans. A USDA declaration will automatically follow a major disaster declaration for counties designated major disaster areas and those that are contiguous to declared counties, including those that are across state lines. As part of an agreement with the USDA, the SBA offers low interest loans for eligible businesses that suffer economic losses in declared and contiguous counties that have been declared by the USDA. These loans are referred to as Economic Injury Disaster Loans. These are discussed in Section 4.2.4.

Based on the disaster declaration history provided in Table 4-3, Lake County is among the many counties in California susceptible to disaster. Details on federal and state disaster declarations were obtained by the HMPC, FEMA, and Cal OES and compiled in chronological order in Table 4-3. A review of state declared disasters indicates that Lake County received 22 state declarations between 1950 and 2017. Of the 22 state declarations: 14 were associated with severe winter storms, heavy rains, or flooding; 2 were for drought; 2 were from economic disasters, 2 were for freeze and severe weather conditions; 1 was for fire, and 1 was for road damage. A review of federal disasters shows 23 federal disaster declarations. Of these 23 federal declarations: 15 were associated with severe winter storms, heavy rains, or flooding; 7 were for wildfire, and 1 was for hurricane (a nationwide declaration for Katrina evacuations). A summary of these events by disaster type is shown in Table 4-4. THERE MAY BE ONE FOR THE RECENT FIRES – FM WILL MONITOR

Table 4-3 Lake County State and Federal Disaster Declarations, 1950-2017

Year Disaster Disaster Type Disaster Disaster # State Federal Name Cause Declaration # Declaration # 2017 California Flood Storms DR-4308 REQUESTED 4/1/2017 Severe Winter FROM CAL Storms, OES Flooding, Mudslides

Lake County Public Review Draft 4-6 Local Hazard Mitigation Plan Update January 2018 Year Disaster Disaster Type Disaster Disaster # State Federal Name Cause Declaration # Declaration # 2017 California Flood Storms DR-4301 REQUESTED 2/14/2017 Severe Winter FROM CAL Storms, OES Flooding, Mudslides 2016 Clayton Fire Fire Fire FM-5145 – 8/14/2016 2015 Valley Fire and Fire Fire DR-4240 – 8/22/2015 Butte Fire 2015 Valley Fire Fire Fire FM-5112 – 9/12/2015 2015 Rocky Fire Fire Fire FM-5093 – 7/29/2015 2014 California Drought Drought GP 2014-13 1/17/2014 – Drought 2012 Wye Fire Fire Fire FM-5004 – 8/13/2012 2006 2006 June Flood Storms DR 1646 – 6/5/2006 Storms 2005/2006 2005/06 Flood Storms DR‐1628 – 2/3/2006 Winter Storms 2005 Hurricane Economic Hurricane EM‐3248 2005 – 9/13/2005 Katrina Evacuations 2003 State Road Road Damage Flood GP 2003 1/1/2003 – Damage 2001 Energy Economic Greed GP 2001 1/1/2001 – Emergency 1998 1998 El Nino Flood Storms DR‐1203 Proclaimed 2/19/1998 Floods 1997 1997 January Flood Storms DR‐1155 1/2/97‐ 1/4/1997 Floods 1/31/97 1996 Lake County Fire Fire DC-96-03 – 8/1/1996 Fire 1995 California Flood Storms DR-1046 Proclaimed 3/12/1995 Severe Winter Storms, Flooding, Landslides, Mud Flows 1995 1995 Severe Flood Storms DR‐1044 1/6/95‐ 1/13/1995 Winter Storms 3/14/95 1987 1987 Fires Fire Fire GP 9/10/87, – 9/3/87 1986 1986 Storms Flood Storms DR‐758 2/18‐86- 2/18/1986 3/12/86 1985 Hidden Valley Fire Fire FM-2055 – 7/11/1985 Lake Fire

Lake County Public Review Draft 4-7 Local Hazard Mitigation Plan Update January 2018 Year Disaster Disaster Type Disaster Disaster # State Federal Name Cause Declaration # Declaration # 1983 Winter Storms Flood Flood DR‐677 12/8/82‐ 2/9/1983 3/21/83 1980 April Storms Flood Storms – 4/1/1980 – 1979 Gasoline Economic OPEC – 5/8/1979- – Shortage 11/13/79 1977 1977 Drought Drought Drought EM-3023 1/20/1977 – 1972 1972 Freeze Freeze Freeze – 7/13/1972 – 1970 1970 Freeze Freeze Freeze – 5/1/70, – 5/19/70, 6/8/70, 6/10/70, 7/24/70 1970 1970 Northern Flood Flood DR 283 1/27/1970 - 2/16/1970 California 3/2/1970 Flooding 1964 1964 Late Flood Storms DR-183 – 12/24/1964 Winter Storms 1963 1963 Floods Flood Storms DR-145 2/7/63, 2/25/63 and Rains 2/26/63, 2/29/63, & 4/22/63 1963 1963 Floods Flood Storms – 2/14/1964 – 1958 1958 April Flood Storms DR-52 4/5/1958 4/4/1958 Storms and Floods 1958 1958 February Flood Storms CDO 58-03 2/26/1958 – Storms and Floods 1955 1955 Floods Flood Flood DR-47 12/22/1955 12/23/1955 1950 1950 Floods Flood Flood OCD 50-01 11/21/1950 – Source: Cal OES, FEMA

Table 4-4 Lake County – State and Federal Disaster Declarations Summary 1950-2017

Disaster Type Federal Declarations State Declarations Count Years Count Years Drought 0 – 2 1977, 2014 Economic 0 – 2 1979, 2001 Fire 7 1985, 1996, 2012, 2015 (three 1 1987 times), 2016 Flood (including heavy 15 1955, 1958, 1963, 1964, 1970, 14 1950, 1955, 1958 (twice), 1963 rains and storms) 1983, 1986, 1995 (two times), (twice), 1970, 1980, 1983, 1986, 1997, 1998, 2005/2006, 2006, 1995 (twice), 1997, 1998 2017 (two times)

Lake County Public Review Draft 4-8 Local Hazard Mitigation Plan Update January 2018 Disaster Type Federal Declarations State Declarations Count Years Count Years Freeze 0 – 2 1970, 1972 Hurricane 1 2005 0 – Road Damage 0 – 1 2003 Totals 23 – 22 – Source: Cal OES, FEMA

Disasters since 2012

As detailed above, there have been six FEMA disaster declarations since the 2011 plan, three were from wildfires in 2015, one from a wildfire in 2016, and two from rains in early 2017. There was a state disaster declaration for drought in 2014. 4.2 Hazard Profiles

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the…location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

The hazards identified in Section 4.1 Hazard Identification, are profiled individually in this section. These profiles set the stage for Section 4.3 Vulnerability Assessment, where the vulnerability is quantified for each of the priority hazards.

Each hazard is profiled in the following format:

➢ Hazard/Problem Description—This section gives a description of the hazard and associated issues followed by details on the hazard specific to the Lake County Planning Area. Where known, this includes information on the hazard extent, area, seasonal patterns, speed of onset/duration, and magnitude and/or any secondary effects. ➢ Past Occurrences—This section contains information on historical incidents, including impacts where known. The extent or location of the hazard within or near the Lake County Planning Area is also included here. Historical incident worksheets were used to capture information on past occurrences. ➢ Frequency/Likelihood of Future Occurrence—The frequency of past events is used in this section to gauge the likelihood of future occurrences. Where possible, frequency was calculated based on existing data. It was determined by dividing the number of events observed by the number of years on record and multiplying by 100. This gives the percent chance of the event happening in any given year (e.g., three droughts over a 30-year period equates to a 10 percent chance of experiencing a drought in any given year). The likelihood of future occurrences is categorized into one of the following classifications: ✓ Highly Likely—Near 100 percent chance of occurrence in next year or happens every year ✓ Likely—Between 10 and 100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less ✓ Occasional—Between 1 and 10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years

Lake County Public Review Draft 4-9 Local Hazard Mitigation Plan Update January 2018 ✓ Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years. ➢ Climate Change—This section contains the effects of climate change (if applicable). The possible ramifications of climate change on the hazard are discussed.

Section 4.2.20 Natural Hazards Summary provides an initial assessment of the profiles and assigns a level of significance or priority to each hazard. Those hazards determined to be of high or medium significance were characterized as priority hazards that required further evaluation in Section 4.3 Vulnerability Assessment. Those hazards that occur infrequently or have little or no impact on the Planning Area were determined to be of low significance and not considered a priority hazard. Significance was determined based on the hazard profile, focusing on key criteria such as frequency and resulting damage, including deaths/injuries and property, crop, and economic damage. The ability of a community to reduce losses through implementation of existing and new mitigation measures was also considered as to the significance of a hazard. This assessment was used by the HMPC to prioritize those hazards of greatest significance to the Planning Area, enabling the County to focus resources where they are most needed.

The following sections provide profiles of the natural hazards that the HMPC identified in Section 4.1 Hazard Identification. The severe weather hazards are discussed first because it is the secondary hazards generated by severe weather (e.g., flood and wildfire) that can result in the most significant losses. The other hazards follow alphabetically.

Data Sources

In general, information provided by planning team members is integrated into this section with information from other data sources. The data sources listed below formed the basis for this Hazard Profiles portion of the plan. Where data and information from these studies, plans, reports, and other data sources were used, the source is referenced as appropriate throughout this risk assessment.

➢ 2012 Sacramento River Individual Agency Summary Reports ➢ 2013 State of California Multi-Hazard Mitigation Plan ➢ Cal-Adapt ➢ CAL FIRE Wildfire History Database ➢ California Climate Adaptation Strategy ➢ California Department of Public Health ➢ California Department of Water Resources Best Available Maps ➢ California Department of Water Resources Division of Safety of Dams ➢ California Division of Mines and Geology ➢ California’s Drought of 2007-2009, An Overview. State of California Natural Resources Agency, California Department of Water Resources.” ➢ California Invasive Plant Council ➢ California Natural Resource Agency ➢ California Office of Emergency Services ➢ Clear Lake Cyanotoxin Monitoring Program ➢ Climate Change and Health Profile Report – Lake County ➢ Climate Change Impacts in the United States ➢ Enhanced Fujita Scale. National Oceanic and Atmospheric Administration Storm Prediction Center.

Lake County Public Review Draft 4-10 Local Hazard Mitigation Plan Update January 2018 ➢ Federal Emergency Management Agency – Disaster Declaration Database ➢ Federal Emergency Management Agency – Wind Zones in the United States ➢ Federal Emergency Management Agency: Building Performance Assessment: Oklahoma and Kansas Tornadoes ➢ Federal Emergency Management Agency: Multi-Hazard Identification and Risk Assessment. ➢ Final Clear Lake Watershed Sanitary Survey 2012 Update ➢ Galloway, Jr Dr. Gerald E. Levees in History: The Levee Challenge. Water Policy Collaborative, University of Maryland, Visiting Scholar, USACE, IWR. ➢ Harmful Cyanobacteria Blooms and Their Toxins in Clear Lake and The Sacramento-San Joaquin Delta ➢ Intergovernmental Panel on Climate Change ➢ Lake County 2010 Cyanobacteria Report ➢ Lake County Agricultural Commissioner Crop Reports ➢ Lake County Community Wildfire Protection Plan ➢ Lake County Department of Water Resources ➢ Lake County Emergency Operations Plan ➢ Lake County General Plan ➢ Lake County General Plan Background Report ➢ Lake County Digital Flood Insurance Rate Map ➢ Lake County Flood Insurance Study (2005 Adopted and Preliminary 2014) ➢ Lake County Housing Element ➢ Lake County Public Works ➢ Marine Invasive Species Act of 2003 ➢ National Aeronautics and Space Administration ➢ National Climate Assessment ➢ National Climatic Data Center Storm Events Database. ➢ National Drought Mitigation Center ➢ National Flood Insurance Program ➢ National Integrated Drought Information System ➢ National Oceanic and Atmospheric Administration Storm Prediction Center ➢ National Oceanic and Atmospheric Administration’s National Climatic Data Center ➢ National Park Service ➢ National Performance of Dams Program ➢ National Weather Service Heat Index ➢ Public Policy Institute of California. If drought continues: Environment and poor rural communities most likely to suffer. [press release]. ➢ Science Magazine ➢ Southern California Association of Governments ➢ State of California Department of Conservation Farmland Mapping and Monitoring Program ➢ Strategic Fire Plan: Sonoma-Lake-Napa Unit ➢ SWAMP HAB Field Guide ➢ Underwood, E. Models predict longer, deeper US droughts. Science, 347(6223) 707 DOI: 10.1126/science.347.6223.707. 2015. ➢ United State Geologic Survey. Earthquake Intensity Zonation and Quaternary Deposits, Miscellaneous Field Studies Map 9093, 1977. ➢ US Army Corps of Engineers ➢ US Bureau of Reclamation

Lake County Public Review Draft 4-11 Local Hazard Mitigation Plan Update January 2018 ➢ US Department of Agriculture ➢ US Department of Agriculture – Farm Service Agency Secretarial Disasters Declarations ➢ US Department of Transportation Pipeline and Hazardous Materials Safety Administration ➢ US Drought Monitor ➢ US Fish and Wildlife Service ➢ US Geological Survey Publication 2014-3120 ➢ US Geological Survey Open File Report 2015‐3009 ➢ US Geological Survey – Biological Resource Division ➢ US Geological Survey – Volcanic Ash: Effect & Mitigation Strategies ➢ USA Today ➢ Western Regional Climate Center

4.2.1. Severe Weather: General

Severe weather is generally any destructive weather event, but usually occurs in the Lake County Planning Area as localized storms that bring heavy rain, lightning, and strong winds.

The National Oceanic and Atmospheric Administration’s National Climatic Data Center (NCDC) has been tracking severe weather since 1950. Their Storm Events Database contains data on the following: all weather events from 1993 to current (except from 6/1993-7/1993); and additional data from the Storm Prediction Center, which includes tornadoes (1950-1992), thunderstorm winds (1955-1992), and hail (1955-1992). This database contains 131 severe weather events that occurred in Lake County between January 1, 1950, and March 31, 2017. Table 4-5 summarizes these events.

Table 4-5 NCDC Severe Weather Events for Lake County 1950-3/31/2017*

Event Type Number Deaths Deaths Injuries Injuries Property Crop of Events (indirect (indirect) Damage Damage Blizzard 1 0 0 0 0 $0 $0 Debris Flows 2 0 0 0 0 $300,000 $0 Drought 15 0 0 0 0 $0 $0 Flash Flood 1 0 0 0 0 $0 $0 Flood 10 1 0 1 0 $23,410,000 $0 Frost/Freeze 2 0 0 0 0 $0 $0 Hail 1 0 0 0 0 $0 $0 Heat 1 0 0 0 0 $0 $0 Heavy Rain 5 0 0 0 0 $0 $0 Heavy Snow 3 0 0 0 0 $0 $0 High Wind 12 0 0 0 0 $168,000 $0 Strong Wind 1 0 0 0 0 $1,000 $0 Wildfire 10 5 0 25 0 $1,500,000 $0 Winter Storm 62 0 0 0 0 $0 $0 Winter Weather 5 0 0 0 0 $0 $0

Lake County Public Review Draft 4-12 Local Hazard Mitigation Plan Update January 2018 Event Type Number Deaths Deaths Injuries Injuries Property Crop of Events (indirect (indirect) Damage Damage Total 131 6 0 26 0 $25,379,000 $0 Source: NCDC *Note: Losses reflect totals for all impacted areas

The NCDC table above summarize severe weather events that occurred in Lake County. Only a few of the events actually resulted in state and federal disaster declarations. It is further interesting to note that different data sources capture different events during the same time period, and often display different information specific to the same events. While the HMPC recognizes these inconsistencies, they see the value this data provides in depicting the County’s “big picture” hazard environment.

As previously mentioned, most all of Lake County’s state and federal disaster declarations have been a result of severe weather. For this plan, severe weather is discussed in the following subsections:

➢ Extreme Heat ➢ Heavy Rains, Snow, and Storms (Hail/Lightning/Wind/Tornadoes) ➢ High Wind

While the HMPC decided not to include cold and freeze as a hazard, cold weather does happen periodically, with little effect to the County. Record colds are shown in Table 4-6.

Table 4-6 Lake County – Record Cold Temperatures by Month from 1920 to 2002

Month Temperature Date Month Temperature Date January 12 1/30/1975 July 35 7/10/1953 February 15 2/6/1989 August 34 8/31/1982 March 21 3/3/1966 September 12 9/28/1982 April 24 4/1/1976 October 23 10/29/1971 May 29 5/13/1942 November 20 11/17/1961 June 30 6/8/1950 December 9 12/9/1972 Source: Western Regional Climate Center – Lakeport Coop Station

4.2.2. Severe Weather: Extreme Heat

Hazard/Problem Description

According to information provided by FEMA, extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks. Heat kills by taxing the human body beyond its abilities. In a normal year, about 175 Americans succumb to the demands of summer heat. In the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the heat wave of 1980 more than 1,250 people died. Extreme heat can also affect the agricultural industry. Extreme heat as it affects agriculture in Lake County is discussed further in the agricultural hazards discussion in Section 4.2.4.

Lake County Public Review Draft 4-13 Local Hazard Mitigation Plan Update January 2018 Heat disorders generally have to do with a reduction or collapse of the body’s ability to shed heat by circulatory changes and sweating or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds a level at which the body can remove it, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body’s inner core begins to rise and heat-related illness may develop. Elderly persons, small children, chronic invalids, those on certain medications or drugs, and persons with weight and alcohol problems are particularly susceptible to heat reactions.

Heat emergencies are often slower to develop, taking several days of continuous, oppressive heat before a significant or quantifiable impact is seen. Heat waves do not strike victims immediately, but rather their cumulative effects slowly take the lives of vulnerable populations. Heat waves do not cause damage or elicit the immediate response of floods, fires, earthquakes, or other more “typical” disaster scenarios. While heat waves are obviously less dramatic, they are potentially more deadly. According to the 2013 California State Hazard Mitigation Plan, the worst single heat wave event in California occurred in Southern California in 1955, when an eight-day heat wave resulted in 946 deaths.

The Heat Index describes how hot the heat‐humidity combination makes it feel. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration. As the HI rises, so do health risks.

➢ When the HI is 90°F, heat exhaustion is possible with prolonged exposure and/or physical activity. ➢ When it is 90°‐105°F, heat exhaustion is probable with the possibility of sunstroke or heat cramps with prolonged exposure and/or physical activity. ➢ When it is 105°‐129°F, sunstroke, heat cramps or heat exhaustion is likely, and heatstroke is possible with prolonged exposure and/or physical activity. ➢ When it is 130°F and higher, heatstroke and sunstroke are extremely likely with continued exposure. Physical activity and prolonged exposure to the heat increase the risks.

The NWS has in place a system to initiate alert procedures (advisories or warnings) when extreme heat is expected to have a significant impact on public safety. The expected severity of the heat determines whether advisories or warnings are issued. The NWS HeatRisk forecast provides a quick view of heat risk potential over the upcoming seven days. The heat risk is portrayed in a numeric (0-4) and color (green/yellow/orange/red/magenta) scale which is similar in approach to the Air Quality Index (AQI) or the UV Index. This can be seen in Table 4-7.

Table 4-7 National Weather Service Heat Risk Categories

Category Level Meaning Green 0 No Elevated Risk Yellow 1 Low Risk for those extremely sensitive to heat, especially those without effective cooling and/or adequate hydration Orange 2 Moderate Risk for those who are sensitive to heat, especially those without effective cooling and/or adequate hydration Red 3 High Risk for much of the population, especially those who are heat sensitive and those without effective cooling and/or adequate hydration Magenta 4 Very High Risk for entire population due to long duration heat, with little to no relief overnight Source: National Weather Service

Lake County Public Review Draft 4-14 Local Hazard Mitigation Plan Update January 2018 The NWS office in Sacramento can issue the following heat-related advisory as conditions warrant.

➢ Heat Advisories are issued during events where the HeatRisk is on the Orange/Red threshold (Orange will not always trigger an advisory) ➢ Excessive Heat Watches/Warnings are issued during events where the HeatRisk is in the Red/Magenta output

The Western Regional Climate Center (WRCC) maintains data on weather normal and extremes in the western United States. There are four weather stations in Lake County. The Lakeport station has the longest period of record, and was chosen for this Plan Update. WRCC data for the County is summarized below.

Lake County— Lakeport Weather Station, Period of Record 1966 to 2016)

According to the WRCC, in Lake County, monthly average maximum temperatures in the warmest months (May through October) range from the mid-70s to the low 90s. The highest recorded daily extreme was 112°F on August 10, 1971. In a typical year, maximum temperatures exceed 90°F on 77.5 days.

Figure 4-1 Lake County— Daily Temperature Averages and Extremes

Source: Western Regional Climate Center, www.wrcc.dri.edu/

Table 4-8 Lake County – Record High Temperatures

Month Record High Date Month Record High Date January 79 1/8/1962 July 112 7/13/1972 February 80 2/10/1954 August 112 8/10/1971 March 87 3/31/1966 September 108 9/3/1998 April 92 4/15/1947 October 101 10/3/1980 May 99 5/30/1950 November 91 11/3/1950

Lake County Public Review Draft 4-15 Local Hazard Mitigation Plan Update January 2018 Month Record High Date Month Record High Date June 107 6/15/1966 December 78 12/6/1957 Source: Western Regional Climate Center

Past Occurrences

Disaster Declaration History

There have been no FEMA or Cal OES disasters related to extreme heat, as shown in Table 4-3.

NCDC Events

The NCDC data shows only one extreme heat incident for Lake County since 1993. Specific impacts for this event were not reported in the database. Information for this event shown in Table 4-9.

Table 4-9 NCDC Extreme Heat Events in Lake County 1993 to 3/31/2017*

Event Date Deaths Injuries Property Damage Crop Damage Heat 7/29/2000 0 0 $0 $0 Total 1 0 $0 $0 Source: NCDC *Deaths, injuries, and damages are for the entire event, and may not be exclusive to the County.

Hazard Mitigation Planning Committee Events

The HMPC identified the following events related to extreme temperatures in the Lake County Planning Area.

➢ ANY EVENTS NOT CAPTURED ABOVE?

Likelihood of Future Occurrence

Likely—Temperature extremes are likely to continue to occur annually in the Lake County Planning Area. Temperatures at or above 90°F are common most summer days in the County.

Climate Change and Extreme Heat

The California Climate Adaptation Strategy (CAS), citing a California Energy Commission study, states that “over the past 15 years, heat waves have claimed more lives in California than all other declared disaster events combined.” This study shows that California is getting warmer, leading to an increased frequency, magnitude, and duration of heat waves. These factors may lead to increased mortality from excessive heat, as shown in Figure 4-2.

Lake County Public Review Draft 4-16 Local Hazard Mitigation Plan Update January 2018 Figure 4-2 California Historical and Projected Temperature Increases – 1961 to 2099

Source: Dan Cayan; California Climate Adaptation Strategy

As temperatures increase, California and Lake County will face increased risk of death from dehydration, heat stroke, heat exhaustion, heart attack, stroke and respiratory distress caused by extreme heat. According to the CAS report and the 2013 State of California Hazard Mitigation Plan, by 2100, hotter temperatures are expected throughout the state, with projected increases of 3-5.5°F (under a lower emissions scenario) to 8-10.5°F (under a higher emissions scenario). These changes could lead to an increase in deaths related to extreme heat in Lake County.

Cal Adapt also noted that overall temperatures are expected to rise substantially throughout this century. During the next few decades, scenarios project average temperature to rise between 1 and 2.3°F; however, the projected temperature increases begin to diverge at mid-century so that, by the end of the century, the temperature increases projected in the higher emissions scenario (A2) are approximately twice as high as those projected in the lower emissions scenario (B1).

These projections also differ depending on the time of year and the type of measurement (highs vs. lows), all of which have different potential effects to the state's ecosystem health, agricultural production, water use and availability, and energy demand. Future temperature estimates from Cal-Adapt are shown in Figure 4-3.

Lake County Public Review Draft 4-17 Local Hazard Mitigation Plan Update January 2018 Figure 4-3 Lake County – Future Temperature Estimates in High and Low Emission Scenarios

Source: Cal-Adapt – Temperature: Decadal Averages Map

4.2.3. Severe Weather: Heavy Rains, Snow, and Storms (Hail/Lightning/Tornadoes)

Hazard/Problem Description

Storms in the Lake County Planning Area are generally characterized by heavy rain often accompanied by strong winds and sometimes lightning and hail. Approximately 10 percent of the thunderstorms that occur each year in the United States are classified as severe. A thunderstorm is classified as severe when it contains one or more of the following phenomena: hail that is three-quarters of an inch or greater, winds in excess of 50 knots (57.5 mph), or a tornado. Heavy precipitation in the Lake County area falls mainly in the fall, winter, and spring months.

Heavy Rain and Storms

The NWS reports that storms and thunderstorms result from the rapid upward movement of warm, moist air. They can occur inside warm, moist air masses and at fronts. As the warm, moist air moves upward, it cools, condenses, and forms cumulonimbus clouds that can reach heights of greater than 35,000 ft. As the rising air reaches its dew point, water droplets and ice form and begin falling the long distance through the clouds towards earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft of air that spreads out at Earth's surface and causes strong winds associated with thunderstorms.

For Lake County, four climatic factors work together to develop the annual season of precipitation: geographical altitude, pacific coastal mountain range barriers, prevailing storm tracks, and air masses.

Lake County Public Review Draft 4-18 Local Hazard Mitigation Plan Update January 2018 ➢ The County’s location in the Pacific Coastal mountain range naturally gives the County varying elevations. The coastal mountain elevations in the County range from an average of 1,200 feet to over 7,000 feet. ➢ Lake County is located in the center of the Pacific Coastal mountain range. The mountain range acts as a barrier to approaching air masses, which approach the mountains from the west, 30 miles inland from the Pacific Ocean coastline. The mountains act as a lifting mechanism as air masses migrate over them, increasing the chance for precipitation. ➢ The winter storm track for Lake County funnels storm systems from a semi-permanent low pressure system in the Gulf of Alaska southward to the California coast following the Westerlies, a global atmospheric wind pattern that provides a relatively consistent westerly flow of air throughout most of the year. ➢ Air masses typical of Lake County are classified as marine polar. The County’s proximity to the Pacific Ocean, in conjunction with the aforementioned storm track, brings cold and moist marine polar air masses over the County throughout much of the year, especially during the winter months.

According to the HMPC, short-term, heavy storms can cause both widespread flooding as well as extensive localized drainage issues. With the increased growth of the area, the lack of adequate drainage systems has become an increasingly important issue. In addition to the flooding that often occurs during these storms, strong winds, when combined with saturated ground conditions, can down very mature trees.

Information from the Lakeport weather station introduced in Section 4.2.1 Severe Weather: General, is summarized below.

Lake County—Lakeport Weather Station, Period of Record 1920 to 2012

According to the WRCC, average annual precipitation in Lake County is 28.36 inches per year. The highest recorded annual precipitation is 44.50 inches in 1973; the highest recorded precipitation for a 24-hour period is 5.43 inches on December 10, 1937. The lowest recorded annual precipitation was 9.96 inches in 1976. Average monthly precipitation for Lake County is shown in Figure 4-4. Daily average and extreme precipitations are shown in Figure 4-5.

Lake County Public Review Draft 4-19 Local Hazard Mitigation Plan Update January 2018 Figure 4-4 Lake County—Monthly Average Total Precipitation

Source: Western Regional Climate Center, www.wrcc.dri.edu/

Figure 4-5 Lake County—Daily Average and Extreme Precipitation

Source: Western Regional Climate Center, www.wrcc.dri.edu/

Snow

During the winter months, the higher elevations of the County can experience snowfall. According to the NWS and the WRCC, winter snow storms can include heavy snow, ice, and blizzard conditions. Heavy snow can immobilize a region, closing roads, stranding commuters, stopping the flow of supplies, and disrupting emergency and medical services. Accumulations of snow can collapse roofs and knock down trees and power lines. In rural areas, homes and farms may be isolated for days, and unprotected livestock

Lake County Public Review Draft 4-20 Local Hazard Mitigation Plan Update January 2018 may be lost. The cost of snow removal, damage repair, and business losses can have a tremendous impact on cities and towns.

Some winter storms are accompanied by strong winds, creating blizzard conditions with blinding wind- driven snow, severe drifting, and dangerous wind chills. Strong winds accompanying these intense storms and cold fronts can knock down trees, utility poles, and power lines. Blowing snow can reduce visibility to only a few feet in areas where there are no trees or buildings. Serious vehicle accidents with injuries and deaths can result.

The upper elevations of Lake County does experience snowfall on a seasonal basis, mostly between the months of November through March. Winter snow storms in this part of the County, including strong winds and blizzard conditions, can result in localized power and phone outages and closures of streets, highways, schools, businesses, and nonessential government operations. During periods of heavy snow there is also an increase in the number and severity of traffic accidents. People can become isolated in their homes and vehicles and are unable to receive essential services.

Lake County—Lakeport Weather Station, Period of Record 1920 to 2012

According to the WRCC, average snowfall is 4.0 inches, as shown in Figure 4-6. The highest annual snowfall fell in 1962, when 4.0 inches fell. Highest monthly snowfall accumulation came in January of 1937, when 15.0 inches fell. Average snowdepths in January through March fall at 0.1 inches. This can be seen in Figure 4-7.

Figure 4-6 Lake County—Snowfall Averages and Extremes

Source: Western Regional Climate Center

Lake County Public Review Draft 4-21 Local Hazard Mitigation Plan Update January 2018 Figure 4-7 Lake County—Snowdepth Averages and Extremes

Source: Western Regional Climate Center

Hail

Hail is formed when water droplets freeze and thaw as they are thrown high into the upper atmosphere by the violent internal forces of thunderstorms. Hail is sometimes associated with severe storms within the Lake County Planning Area. Hailstones are usually less than two inches in diameter and can fall at speeds of 120 miles per hour (mph). Severe hailstorms can be quite destructive, causing damage to roofs, buildings, automobiles, vegetation, and crops.

The National Weather Service classifies hail by diameter size, and corresponding everyday objects to help relay scope and severity to the population. Table 4-10 indicates the hailstone measurements utilized by the National Weather Service.

Table 4-10 Hailstone Measurements

Average Diameter Corresponding Household Object .25 inch Pea .5 inch Marble/Mothball .75 inch Dime/Penny .875 inch Nickel 1.0 inch Quarter 1.5 inch Ping-pong ball 1.75 inch Golf-Ball 2.0 inch Hen Egg 2.5 inch Tennis Ball 2.75 inch Baseball

Lake County Public Review Draft 4-22 Local Hazard Mitigation Plan Update January 2018 Average Diameter Corresponding Household Object 3.00 inch Teacup 4.00 inch Grapefruit 4.5 inch Softball Source: National Weather Service

Lightning

Lightning is defined by the NWS as any and all of the various forms of visible electrical discharge caused by thunderstorms. Thunderstorms and lightning are usually (but not always) accompanied by rain. Cloud- to-ground lightning can kill or injure people by direct or indirect means. Objects can be struck directly, which may result in an explosion, burn, or total destruction. Or, damage may be indirect, when the current passes through or near an object, which generally results in less damage.

Intra-cloud lightning is the most common type of discharge. This occurs between oppositely charged centers within the same cloud. Usually it takes place inside the cloud and looks from the outside of the cloud like a diffuse brightening that flickers. However, the flash may exit the boundary of the cloud, and a bright channel, similar to a cloud-to-ground flash, can be visible for many miles.

Cloud-to-ground lightning is the most damaging and dangerous type of lightning, though it is also less common. Most flashes originate near the lower-negative charge center and deliver negative charge to earth. However, a large minority of flashes carry positive charge to earth. These positive flashes often occur during the dissipating stage of a thunderstorm's life. Positive flashes are also more common as a percentage of total ground strikes during the winter months. This type of lightning is particularly dangerous for several reasons. It frequently strikes away from the rain core, either ahead or behind the thunderstorm. It can strike as far as 5 or 10 miles from the storm in areas that most people do not consider to be a threat (see Figure 4-8). Positive lightning also has a longer duration, so fires are more easily ignited. And, when positive lightning strikes, it usually carries a high peak electrical current, potentially resulting in greater damage.

Lake County Public Review Draft 4-23 Local Hazard Mitigation Plan Update January 2018 Figure 4-8 Cloud to Ground Lightning

Source: National Weather Service

Lightning in the County is also a concern due to the number of fires that have been started by lightning strikes. Wildfire is discussed in more detail in Section 4.2.19.

Tornadoes

Tornadoes and funnel clouds can also occur during these types of severe storms. Tornadoes are another severe weather hazard that can affect the Lake County Planning Area, primarily during the rainy season in the late fall and early spring. Tornadoes form when cool, dry air sits on top of warm, moist air. Tornadoes are rotating columns of air marked by a funnel-shaped downward extension of a cumulonimbus cloud whirling at destructive speeds of up to 300 mph, usually accompanying a thunderstorm. Tornadoes are the most powerful storms that exist. They can have the same pressure differential across a path only 300 yards wide or less as 300-mile-wide hurricanes. Figure 4-9 illustrates the potential impact and damage from a tornado.

Lake County Public Review Draft 4-24 Local Hazard Mitigation Plan Update January 2018 Figure 4-9 Potential Impact and Damage from a Tornado

Source: FEMA: Building Performance Assessment: Oklahoma and Kansas Tornadoes

Prior to February 1, 2007, tornado intensity was measured by the Fujita (F) scale. This scale was revised and is now the Enhanced Fujita scale. Both scales are sets of wind estimates (not measurements) based on damage. The new scale provides more damage indicators (28) and associated degrees of damage, allowing for more detailed analysis and better correlation between damage and wind speed. It is also more precise because it takes into account the materials affected and the construction of structures damaged by a tornado. Table 4-11 shows the wind speeds associated with the original Fujita scale ratings and the damage that could result at different levels of intensity. Table 4-12 shows the wind speeds associated with the Enhanced Fujita Scale ratings.

Table 4-11 Original Fujita Scale

Fujita (F) Fujita Scale Wind Typical Damage Scale Estimate (mph) F0 < 73 Light damage. Some damage to chimneys; branches broken off trees; shallow- rooted trees pushed over; sign boards damaged. F1 73-112 Moderate damage. Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off roads. F2 113-157 Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground. F3 158-206 Severe damage. Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown. F4 207-260 Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated.

Lake County Public Review Draft 4-25 Local Hazard Mitigation Plan Update January 2018 Fujita (F) Fujita Scale Wind Typical Damage Scale Estimate (mph) F5 261-318 Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters (109 yards); trees debarked; incredible phenomena will occur. Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/f-scale.html

Table 4-12 Enhanced Fujita Scale

Enhanced Fujita (EF) Scale Enhanced Fujita Scale Wind Estimate (mph) EF0 65-85 EF1 86-110 EF2 111-135 EF3 136-165 EF4 166-200 EF5 Over 200 Source: National Oceanic and Atmospheric Administration Storm Prediction Center, www.spc.noaa.gov/faq/tornado/ef-scale.html

Tornadoes can cause damage to property and loss of life. While most tornado damage is caused by violent winds, the majority of injuries and deaths generally result from flying debris. Property damage can include damage to buildings, fallen trees and power lines, broken gas lines, broken sewer and water mains, and the outbreak of fires. Agricultural crops and industries may also be damaged or destroyed. Access roads and streets may be blocked by debris, delaying necessary emergency response.

Past Occurrences

Disaster Declaration History

A search of FEMA and Cal OES disaster declarations turned up multiple events. Heavy rains and storms have caused flooding in the County. Events where flooding resulted in a state or federal disaster declaration are shown in Table 4-13.

Table 4-13 Lake County – Disaster Declarations from Heavy Rain and Storms 1950-2017

Disaster Type Federal Declarations State Declarations Count Years Count Years Flood (including heavy 15 1955, 1958, 1963, 1964, 1970, 14 1950, 1955, 1958 (twice), 1963 rain and storms) 1983, 1986, 1995 (two times), (twice), 1970, 1980, 1983, 1986, 1997, 1998, 2005/2006, 2006, 1995 (twice), 1997, 1998 2017 (two times) Source: FEMA, Cal OES

NCDC Events

The NCDC data recorded 73 hail, heavy rain, and winter weather incidents for Lake County since 1950. No incidents of tornado were found in the NCDC database for the County. A summary of these events is

Lake County Public Review Draft 4-26 Local Hazard Mitigation Plan Update January 2018 shown in Table 4-14 Events in the NCDC database specific to Lake County showing damages, deaths, or injuries are detailed below the table.

Table 4-14 NCDC Severe Weather Events in Lake County 1950-3/31/2017

Event Type Number Deaths Deaths Injuries Injuries Property Crop of Events (indirect (indirect) Damage Damage Hail 1 0 0 0 0 $0 $0 Heavy Rain 5 0 0 0 0 $0 $0 Winter Storm 62 0 0 0 0 $0 $0 Winter Weather 5 0 0 0 0 $0 $0 Total 73 0 0 0 0 $ 0 $0 Source: NCDC

➢ January 4, 2008 –A powerful Pacific storm brought widespread winds gusting to 60 mph and in some areas to more than 80 mph across interior Northern California, causing extensive damage and numerous power outages. Rainfall and liquid equivalent amounts ranged from 2 to 3 inches in the northern Central Valley and 4 to 11 inches in the mountains of Shasta County. Snowfall totals of 3 to 11 feet were reported in the northern Sierra Nevada Mountains, with winds up to and possibly exceeding 100 mph coupled with heavy snow bringing blizzard conditions. A 73-mph gust was measured at the Lyons Valley RAWS automated weather station, 10 miles northwest of Lakeport. Numerous buildings were damaged due directly to the wind and/or to flying debris and falling trees and branches. Power was out to many customers for up to a day. A 65 mph wind gusts was recorded 18 miles south southeast of Saddle Camp. Numerous buildings were damaged due directly to the wind and/or to flying debris and falling trees and branches. Power was out to many customers for up to a day. No deaths or injuries were reported. $168,000 in damages were attributed to the storm, though not all in Lake County. ➢ March 6, 2016 – A very wet pattern brought moderate precipitation and high snow levels at first, followed by a stronger and colder system with heavy mountain snow, local flooding, and strong and damaging Valley winds. Additional weather systems continued precipitation through Sunday and Monday. Strong winds uprooted a 90-foot-high pine tree. $1,000 in damages and cleanup costs were reported.

Hazard Mitigation Planning Committee Events

The HMPC noted the following events:

➢ In September 2003, thunderstorm activity from a former Pacific Ocean Hurricane produced hundreds of lightning strikes throughout the Mendocino National Forest and Lake County areas.

Likelihood of Future Occurrence

Likely – Based on NCDC data and HMPC input, 73 heavy rain, hail, lightning, and thunderstorm wind incidents over a 67-year period (1950-2016) equates to a severe storm event every year. As noted, this database likely doesn’t capture all heavy rain, hail, lightning, tornado, and winter weather events. Severe weather is a well-documented seasonal occurrence that will continue to occur often in the Lake County Planning Area.

Lake County Public Review Draft 4-27 Local Hazard Mitigation Plan Update January 2018 Climate Change and Heavy Rains, Snow, and Storms

According to the CAS, while average annual rainfall may increase or decrease slightly, the intensity of individual rainfall events is likely to increase during the 21st century. This may bring stronger thunderstorm winds. It is unlikely that hail will become more common in the County. The amount of lightning and tornadoes is not projected to change.

Cal-Adapt noted that, on average, the projections show little change in total annual precipitation in California. Furthermore, among several models, precipitation projections do not show a consistent trend during the next century. The Mediterranean seasonal precipitation pattern is expected to continue, with most precipitation falling during winter from North Pacific storms. One of the four climate models projects slightly wetter winters, and another projects slightly drier winters with a 10 to 20 percent decrease in total annual precipitation. However, even modest changes would have a significant impact because California ecosystems are conditioned to historical precipitation levels and water resources are nearly fully utilized. Future precipitation estimates for the County are shown in Figure 4-10.

Figure 4-10 Lake County– Future Precipitation Estimates: High and Low Emission Scenarios

Source: Cal-Adapt – Precipitation: Decadal Averages Map

Cal-Adapt also noted that March snow levels in the eastern, higher-elevation portion of the region will drop to almost zero by the 2090s, a decrease of 2 to 10 inches from 2010 levels. In areas with more snow, 3 to 5 inches of reduction will occur by 2050. In areas with currently little snow (<3 inches), the snowpack is projected to be near zero by 2050. (CCSM3 climate model; high emissions scenario)

4.2.4. Severe Weather: High Winds

Hazard/Problem Description

High winds, often accompanying severe storms and thunderstorms, can cause significant property and crop damage, threaten public safety, and have adverse economic impacts from business closures and power loss.

Lake County Public Review Draft 4-28 Local Hazard Mitigation Plan Update January 2018 The Planning Area is subject to significant, non-tornadic (straight-line), winds. High winds, as defined by the NWS glossary, are sustained wind speeds of 40 mph or greater lasting for 1 hour or longer, or winds of 58 mph or greater for any duration. These winds may occur as part of a seasonal climate pattern or in relation to other severe weather events such as thunderstorms. Straight-line winds may also exacerbate existing weather conditions by increasing the effect on temperature and decreasing visibility due to the movement of particulate matters through the air, as in dust and snow storms. The winds may also exacerbate fire conditions by drying out the ground cover, propelling fuel around the region, and increasing the ferocity of exiting fires. These winds may damage crops, push automobiles off roads, damage roofs and structures, and cause secondary damage due to flying debris.

Figure 4-11 depicts wind zones for the United States. The map denotes that Lake County falls into Zone I, which is characterized by high winds of up to 130 mph.

Figure 4-11 Wind Zones in the United States

Source: Federal Emergency Management Agency

Lake County Public Review Draft 4-29 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no past federal or state disaster declarations due to high winds, according to Table 4-3.

NCDC Events

The NCDC data recorded 13 high wind incidents for Lake County since 1950. No incidents of tornado were found in the NCDC database for the County. A summary of these events is shown in Table 4-15. Events in the NCDC database specific to Lake County showing damages, deaths, or injuries are detailed below the table.

Table 4-15 NCDC Severe Weather Events in Lake County 1950-3/31/2017

Event Type Number Deaths Deaths Injuries Injuries Property Crop of Events (indirect (indirect) Damage Damage High Wind 12 0 0 0 0 $168,000 $0 Strong Wind 1 0 0 0 0 $1,000 $0 Total 13 0 0 0 0 $169,000 $0 Source: NCDC

HMPC Events

➢ The HMPC noted that wind was the issue in the County in the recent fires. ➢ In November of 2013, the County experienced a windstorm that lasted 3 ½ days. No information on damages were provided.

Lake County Public Review Draft 4-30 Local Hazard Mitigation Plan Update January 2018 Likelihood of Future Occurrence

Likely – Based on NCDC data and HMPC input, 13 wind incidents over a 62-year period (1955-2016) equates to a severe storm event every 4.7 years. As noted, this database likely doesn’t capture all wind events. Severe weather is a well-documented seasonal occurrence that will continue to occur often in the Lake County Planning Area.

Climate Change and High Winds

According to the CAS, while average annual rainfall may increase or decrease slightly, the intensity of individual thunderstorm events is likely to increase during the 21st century. This may bring stronger thunderstorm winds. The CAS does not discuss non-thunderstorm winds.

4.2.5. Agricultural Hazards

Hazard/Problem Description

Agriculture has always been an integral part of Lake County and has continually grown and changed along with the County. Today, the soils and climate of Lake County make it an ideal area to sustain many agricultural endeavors. Agriculture in Lake County is a mosaic of farm land intermingled with other uses in the rural setting which typifies the County. This land provides marketable products, open space, wildlife habitat, watershed and an aesthetic environment. According to the California Department of Conservation’s Farmland Mapping and Monitoring Program (FMPP), the County has approximately 309 acres of prime farmland, 1,274 acres of farmland of statewide importance, 476 acres of unique farmland, 23,141 acres of farmland of local importance, and 117,278 acres of grazing land. These numbers have been reduced since 2004 due to increased development in the County. (see Table 4-16).

Table 4-16 Lake County Farmland Inventory, 2004, 2014

Soil Category 2004 Acres 2014 Acres Prime Farmland 15,463 10,127 Farmland of Statewide Importance 1,432 827 Unique Farmland 11,999 11,207 Farmland of Local Importance 19,468 23,670 Grazing Land 240,001 23,9724 Urban and Built-Up Land 14,443 15,743 Water 501,385 502,729 Other Land 46,793 46,811 Total Area Inventoried 850,984 850,838 Source: State of California Department of Conservation Farmland Mapping and Monitoring Program, www.conservation.ca.gov/

According to the 2015 Lake County Crop Report, many commodities are grown in Lake County. This includes vegetable crops; nursery and flower products; timber products; fruit and nut crops; livestock and

Lake County Public Review Draft 4-31 Local Hazard Mitigation Plan Update January 2018 poultry; apiary, eggs, and wool products; and pasture and rangeland. The top three commodities for the County are fruit and nut, livestock, and filed and seed crops.

According to the 2015 crop report, the gross value of Lake County Agriculture production for 2015 was $101,135,648. This is an increase of 9%. The increase can be attributed to an increase in the value of the wine grape and pear industries. The gross value of wine grapes was $63,390,181 an increase of 7% from 2014. The total tonnage was 38,786 and the total grape acreage was 9,455, an increase of 673 acres. The tons per acre increased slightly and the average price per ton in-creased by 7%. The wine grape return (price per ton) was the highest on record. In 2015 the gross value of pears was $26,098,171, an increase of 21% from 2014. The total production increased by 9,002 tons, and the price per ton increased by 2%. The pear price per ton on all Bartlett pears was the highest on record. The gross value of walnuts was $5,383,560 a decrease of 25% and production slightly decreased. The price per ton decreased by 19% and acreage increased to 4,016. There was a big difference in the price per pound for conventional growers ($.65) and organic growers ($3.00). Increases were noted in nursery production (36%), miscellaneous fruit (14%), livestock and poultry products (23%), and vegetables (3%). Decreases were noted in livestock productions (4%), field crops (33%) and timber (1,250%).

A summation of crop production values, sourced from the Lake County Agricultural Commissioner’s Annual Crop Reports, from 2011-2015 for Lake County is shown in Table 4-17.

Table 4-17 Lake County – Value of Agricultural Production 2011-2015

Crop 2011 2012 2013 2014 2015 Fruit & Nut $62,136,847 $78,634,818 $89,567,410 $85,560,872 $94,977,570 Livestock $1,959,100 $2,390,555 $2,718,983 $2,306,555 $2,219,530 Productions Livestock & $113,121 $149,321 $135,685 $137,760 $179,034 Poultry Products Nursery $793,107 $1,443,295 $640,458 $941,566 $1,474,200 Vegetable $295,894 $344,182 $411,255 $286,309 $296,002 Field & Seed $148,300 $1,872,340 $2,217,400 $2,600,000 $1,959,865 Crops Timber $46,915 $7,900 $181,920 $397,690 $29,447 Total $66,824,284 $84,842,411 $96,173,111 $92,230,752 $101,135,649 Source: Lake County Agricultural Commissioner

According to the HMPC, agricultural losses occur on an annual basis and are usually associated with severe weather events, including heavy rains, floods, heat, and drought. The 2013 State of California Multi-Hazard Mitigation Plan attributes most of the agricultural disasters statewide to drought, freeze, and insect infestations. Other agricultural hazards include fires, crop and livestock disease, insects, and noxious weeds.

Lake County Public Review Draft 4-32 Local Hazard Mitigation Plan Update January 2018 Natural Disasters and Severe Weather

According to the US Department of Agriculture (USDA), every year natural disasters, such as droughts, earthquakes, extreme heat and cold, floods, fires, earthquakes, hail, landslides, and tornadoes, challenge agricultural production. Because agriculture relies on the weather, climate, and water availability to thrive, it is easily impacted by natural events and disasters. Agricultural impacts from natural events and disasters most commonly include: contamination of water bodies, loss of harvest or livestock, increased susceptibility to disease, and destruction of irrigation systems and other agricultural infrastructure. These impacts can have long lasting effects on agricultural production including crops, forest growth, and arable lands, which require time to mature.

Insect Pests

Lake County is threatened by a number of insects that, under the right circumstances, can cause severe economic and environmental harm to the agricultural industry. Insects of concern to plants and crops include the gypsy moth, Japanese beetle, light brown apple moth, European grapevine moth, light brown apple moth, European pine shoot moth, Mediterranean fruit flies, Oriental fruit flies, melon flies, and glassy-winged sharpshooter. The Lake County Department of Agriculture traps and monitors all of these agricultural pests. Pest detection is a proactive program that seeks to identify exotic, invasive insects. These pests have a wide host ranges and are difficult and costly to manage once established. Early detection is essential for quick and efficient eradication. Public participation is critical to the success of this program, since staff relies on the goodwill of property owners who allow traps to be placed on their properties. The Agriculture Department deployed 545 traps between spring and fall in 2015.

Weeds

Noxious weeds, defined as any plant that is or is liable to be troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate, are also of concern. Noxious weeds within the Planning Area include those listed on Table 4-18.

Table 4-18 Lake County Weeds of Concern

Species of Concern Barb Goatgrass Giant Reed Downybrome Spotted Yellow Starthistle Jubatagrass Knapweed Scotch Broom Brazilian Egeria Goat’s Rule French broom English ivy Hyrilla Perrenial Urugray and Purple loosestrife Parrotfeather Eurasian Scotch thistle pepperweed creeping water watermilfoil primrose Himalayan Red sesbania Spanish broom Medusahead Smallflower Saltcedar blackberry tamarisk Source: California Invasive Plant Council

The Lake County Department of Agriculture uses mechanical and chemical control measures to contain all of these agricultural pests. Noxious weeds have been introduced in the Planning Area by a variety of means, including through commercial nurseries. An absence of natural controls, combined with the aggressive

Lake County Public Review Draft 4-33 Local Hazard Mitigation Plan Update January 2018 growth characteristics and unpalatability of many of these weeds, allows these weeds to dominate and replace more desirable native vegetation. Negative effects of weeds include the following:

➢ Loss of wildlife habitat and reduced wildlife numbers; ➢ Loss of native plant species; ➢ Reduced livestock grazing capacity; ➢ Increased soil erosion and topsoil loss; ➢ Diminished water quality and fish habitat; ➢ Reduced cropland and farmland production; and ➢ Reduced land value and sale potential.

According to the HMPC, the consequences of agricultural disasters to the Planning Area include ruined plant crops, dead livestock, ruined feed and agricultural equipment, monetary loss, job loss, and possible multi-year effects (i.e., trees might not produce if damaged, loss of markets, food shortages, increased prices, possible spread of disease to people, and loss or contamination of animal products). When these hazards cause a mass die-off of livestock, other issues occur that include the disposal of animals, depopulation of affected herds, decontamination, and resource problems. Those disasters related to severe weather may also require the evacuation and sheltering of animal populations. Overall, any type of severe agricultural disaster can have significant economic impacts on both the agricultural community and the entire Lake County Planning Area.

Past Occurrences

Disaster Declaration History

Located in the Pacific Coastal mountain range between 1,200 and 7,000 feet in elevation, the agricultural lands of Lake County have historically been affected by weather related events such as freeze, heavy rain, and drought. The severe weather events can have devastating effects on fruit set and harvest causing losses in yield and affecting quality. The Lake County Department of Agriculture provided information on disaster declarations from 2012 through 2016. These are shown in Table 4-19.

Table 4-19 Lake County – USDA Disaster Declarations

Disaster Declaration Disaster Cause Primary or Contiguous Crop Disaster Year Number County S3246 Freezing temperatures Contiguous 2012 S3379 Drought Contiguous 2012 S3452 Drought Contiguous 2012 S3565 Drought – FAST TRACK Contiguous 2013 S3569 Drought – FAST TRACK Primary 2013 S3637 Drought – FAST TRACK Primary 2014 S3743 Drought Contiguous 2014 S3797 Drought Primary 2014 S3784 Drought – FAST TRACK Primary 2015

Lake County Public Review Draft 4-34 Local Hazard Mitigation Plan Update January 2018 Disaster Declaration Disaster Cause Primary or Contiguous Crop Disaster Year Number County S3943 Drought Contiguous 2015 S3964 Drought – FAST TRACK Contiguous 2016 S4163 Drought – FAST TRACK Primary 2017 Source: Lake County Agricultural Commissioner, US Farm Service Agency

NCDC Events

The NCDC does not track agriculture events.

Hazard Mitigation Planning Committee Events

The HMPC noted that agriculture events occur yearly, though with varying levels of damages.

Likelihood of Future Occurrence

Highly Likely—As long as severe weather events, insects, and weeds continue to be an ongoing concern to the Lake County Planning Area, the potential for agricultural losses remains.

Climate Change and Agricultural Hazards

According to the CAS, addressing climate change in agriculture will encompass reducing vulnerability through adapting to the ongoing and predicted impacts of climate. Agriculture in California is vulnerable to predicted impacts of climate change, including less reliable water supplies, increased temperatures, and increased pests.

4.2.6. Aquatic Biologic Hazards: Cyanobacteria Bloom

Hazard/Problem Description

Clear Lake is California’s largest freshwater lake, covering 43,000 acres (68 square miles) of surface area with 110 miles of shoreline. The lake’s vast size gives it the ability to support large populations of waterfowl such as ducks, pelicans, grebes, blue herons, egrets, and osprey year-round and winter populations of bald eagles and white pelicans.

The average depth of the lake is about 25 feet. Historically, the natural level of Clear Lake was maintained by the Grigsby Riffle, a rock sill located at the confluence of Cache and Siegler Canyon Creeks. The Cache Creek Dam, controlled by the Yolo County Flood Control District, is about three miles downstream of the Riffle. The dam is capable of releasing far more water than the upstream channel to the riffle is physically capable of accommodating. Because of the limited discharge capacity of the upstream channel, it is possible for the lake to flood in the near-shore areas during extended periods of heavy rainfall.

Prevailing winds and the lake's modest depth facilitate vertical mixing. Submerged thermal springs and gas vents in the floor of the lake further promote mixing. These geologic features are not considered to impact

Lake County Public Review Draft 4-35 Local Hazard Mitigation Plan Update January 2018 the Clear Lake water utilities negatively. The lake stratifies during warm summer days, but generally recirculates during the cooler nights unless surface conditions are unusually calm.

Clear Lake has three distinct arms with distinct drainage basins: Upper Arm, Oaks Arm, and Lower Arm. Westerly winds push surface water from the Upper Arm into the Oaks Arm and Lower Arm, setting up a return flow of bottom water. "The Narrows" limits those exchanges. It takes about 100 days for water in the Lower Arm and Oaks Arm to be completely exchanged with the Upper Arm due to wind driven currents.

The growth of blue-green algae can cause considerable degradation of the lake shore and surface environment during summer and fall. Algal problems are typically most serious at the eastern end of the lake where prevailing winds can push floating algae into huge rotting mats that produce strong odors. Erosion of sediments from the upper watershed carries nutrients that contribute to algal growth.

The major manifestation of water pollution is the algae in Clear Lake. Although the problem appears to be largely a result of natural conditions conducive to algae growth, man’s activities including land disturbance and fertilizing the soil no doubt contribute to the problem. Other pollutants, organic pesticides and mercury, found in the lake are hazardous to the fish and, in significant enough concentration, result in fish kills.

Cyanobacteria (blue green algae) is becoming an increasingly significant hazard in Clear Lake. Cyanobacteria can produce toxins that can be harmful for animals and people when consumed at high levels. Currently research in not clear on what levels of toxins are harmful, however, the Environmental Protection Agency recently published conservative guidelines to ensure that human safety is preserved. While current water treatment processes appear to filter out toxins to safe levels, there is the possibility on contamination in the future.

Clear Lake is identified as an impaired water body for nutrients and mercury on the State Water Resources Control Board CWA 303d list, and on its southeastern shoreline is Sulphur Bank Mercury Mine, Superfund Site EPA #: CAD980893275, established in 1990. The Clear Lake Nutrient TMDL was adopted in 2006 and the Clear Lake Mercury TMDL was adopted in 2003. California Office of Environmental Health Hazard Assessment issued a fish consumption advisory, most recently updated in 2014, for Clear Lake due to mercury levels in fish tissues. Extensive cyanobacteria harmful algal blooms including the cyanobacteria Microcystis spp. occur in Clear Lake. These are promoted by anthropogenic nutrient loading from runoff of sediment, storm and agricultural waters containing nutrients such as phosphates. Sewage overflows and leaking septics also contribute to the nutrient problem in Clear Lake.

According to the SWAMP HAB Field Guide, there is a cyanobacterial chart and id details cyanobacteria groups and the toxins that they potentially produce. This is shown in Figure 4-12. These connections to potential toxin production are based on published research of laboratory cultures and cyanobacteria collected from the field. Note that research is still finding new connections and this chart is not an exhaustive review of all published cyanobacteria research; use this informational chart with caution and do not solely rely on it to determine risks from cyanobacteria. It is recommended to confirm toxin presence using an analytical method (field toxin detection kits, laboratory based analysis).

The groups of cyanobacteria are identified to the taxonomic level of genus, among this genus are numerous species - it is not necessary to identify cyanobacteria down to the species level to assess potential toxin

Lake County Public Review Draft 4-36 Local Hazard Mitigation Plan Update January 2018 production. Species level identification takes more time and resources. When toxins production has been measured for an individual species, the entire genus that they belong to is assumed to produce toxins - this is a precautionary approach. This chart also highlights that cyanobacteria are capable of producing more than one toxin; therefore, toxin analysis should be planned accordingly.

Lake County Public Review Draft 4-37 Local Hazard Mitigation Plan Update January 2018 Figure 4-12 Cyanobacteria and Known Toxins Chart

Source: SWAMP HAB Field Guide

Lake County Public Review Draft 4-38 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no federal or state disaster declarations from aquatic biological hazards.

NCDC Events

The NCDC does not track aquatic biologic hazards.

Hazard Mitigation Planning Committee Events

In 2009, Clear Lake experienced a heavy bloom of cyanobacteria, primarily lyngbya. These visible blooms were most concentrated at the southern end of the lake where prevailing winds and geographic conditions support the accumulation algae mats. A similar bloom again occurred in 2010. In 2010, Cecile Mioni and Raphael Kudela from the University of California, Santa Cruz performed a series of toxicity investigations regarding the cyanobacteria in Clear Lake. During their 2010 sampling events, Mioni and Kudela noted that algal blooms were dominated by Nitzchia, Melosira, Phormidium cincinnatum, Oocystis, Anabaena spiroides and Microsystis aeruginosa. Potentially harmful cyanobacteria that were found included: Aphanizomenon, Microcystis aeruginosa, Anabaena spiroides, and Lyngbya cincinnati (also known as Phormidium cincinnatum) during the summer. The two dominant “mat-forming” cyanobacteria found in their study were Lyngbya cincinnati and Anabaena spiroides. They concluded that the lake does not appear to have significant recreational risks to toxin exposures, but that the levels of the microcystins (a toxin to humans) would require further investigation.

From June to October 2011, Cecile Mioni and Raphael Kudela provided research and prepared the Harmful Cyanobacteria Blooms and Their Toxins in Clear Lake and The Sacramento-San Joaquin Delta (California) report as part of the SWRCB Surface Water Ambient Monitoring Program (SWAMP). This state funded research had specific objectives to address including:

➢ Monitor monthly discrete and continuous sampling stations located in critical habitats of the Sacramento-San Joaquin Delta and in each arm of Clear Lake in order to: ✓ Perform an assessment of the toxicity of the cyanobacteria growing in Clear Lake and the Sacramento-San Joaquin Delta. ✓ Identify and enumerate harmful cyanobacteria in these two systems using traditional microscopy and molecular methods. ➢ Provide a better understanding of the mechanisms underlying the source, occurrence and toxicity levels of harmful cyanobacteria in these systems, ➢ Investigate possible algae-related symptoms by Lake County residents, domestic animals and wildlife (Dr. Tait, Lake County Department of Health). ➢ Serve as a source of information that will direct and promote actions to improve water quality and enhance other monitoring programs.

Some highlights provided in the conclusions of the Harmful Cyanobacteria Blooms and Their Toxins in Clear Lake and The Sacramento-San Joaquin Delta report recommend taking into account the biological influence of translocation of nutrients between sediment and the water column, preventing or reducing G.

Lake County Public Review Draft 4-39 Local Hazard Mitigation Plan Update January 2018 echinulata at the sediment level rather than the water column to help prevent blooms, examination of internal nutrient cycling of nitrogen and phosphorus and further investigations of iron and sulfates.

On September 8, 2011, CDPH collected samples at various water treatment plants around the lake in response to public concerns in Lake County during the noxious cyanobacteria blooms. These concerns were regarding recreation and drinking water from Clear Lake. The purpose of the sample collection was to measure the concentration of the six microcystins entering water treatment plants and to assess how effectively six microcystins were removed at different stages of treatment. This event involved ten utilities including; BPWD, CMWC, CBIC, CLOCWD, HMWC, CWSC Lucerne, LCSD-Soda Bay, NMWC, RPR, and WMHP. Following the sampling event, all ten utilities received a letter from CDPH indicating the successful removal of the six microcystins was attributed to the optimization of their treatment systems for compounds in both soluble and insoluble form.

Because there are toxins associated with blue-green algae, utilities can be affected in the future with more taste and odor issues. A possible remedy to the severe water quality issues introduce by blue-green algae near intakes could be to install a dual intake system with a switch or automation that allows for one intake to shut off and the other to turn by a limiting detection limit (e.g. pH) or another treatment factor.

The utilities may also consider supporting future investigations to identify any highly carcinogenic nitrogenous disinfection byproducts formed by the algal blooms. If there are byproducts identified directly related to the algal blooms and are found not regulated, local government representatives may want work with state agencies and EPA to establish adequate measures for future monitoring and regulation.

Over the period of 2005 to 2015 Chlorophyll A data collected 5-7 times per year by CA Department of Water Resources in the center of each arm of each lake shows a range of results from the low of 20 ug/L to the high of 270 ug/L.

Likelihood of Future Occurrences

Highly Likely – Cyanobacterial bloom is an annual event in Clear Lake. The severity of it varies by year. Biologists predict that this phenomenon is likely to recur for an unknown period of time. Although a research project has demonstrated only low levels of cyanotoxins to date, the risk for toxin production in algal blooms is known to vary widely with time and location.

4.2.7. Aquatic Biologic Hazards: Quagga Mussels

Hazard/Problem Description

Clear Lake supports considerable growth of vascular aquatic plants. These include native species, and in the past, have included the exotic invasive Hydrilla, which formed mats so dense as to be unsuitable even for fish habitat. The lake is heavily used for recreational boating and supports sport fishing year round. Native fish have been largely replaced by introduced warm-water species, notably black bass, catfish, carp, and largemouth bass. Clear Lake is the source of drinking water for more than 45,000 community residents. The lake is also home to many bass tournaments because of its prize fishing, and residents and tourists alike enjoy various forms of boating and recreation on the lake.

Lake County Public Review Draft 4-40 Local Hazard Mitigation Plan Update January 2018 Quagga and zebra Mussels are an invasive species of the same genus, Dreissena. The two species appear similar and can be mistaken for the other. These mussels are native to Eurasia and have spread across the United States. They have the ability to multiply rapidly and have no natural predator in the United States. When established in a water-body the mussels become an ecological and economical threat. They can remove food and nutrients necessary for other species, clog pipes, damage boat motors. Quagga and zebra mussels are the size of a thumbnail (see Figure 4-13).

The introduction of quagga mussels (often referred to as Dreissenids) to the Pacific Southwest Region brings the potential to extend devastating impacts into a geographical area already challenged with water- related problems.

Figure 4-13 Quagga and Zebra Mussels

Source: US Fish and Wildlife Service

Zebra mussels are an invasive species first recognized in Lake St. Clair, near Detroit, Michigan, in 1988; shortly thereafter, the Quagga mussel was identified. Since then, the Quagga mussel has rapidly spread across much of the western United States and in 2007 was detected at Lake Mead in Nevada. Later surveys found Quagga mussels in Lake Mohave in Nevada, Lake Havasu in Arizona, and the Colorado River Aqueduct System which serves Southern California. In California the first confirmed find of Zebra mussels occurred at San Justo Lake in 2008. These mussels have the ability to survive for a number of days on land by their ability to retain moisture. As a result, there is concern these mussels can spread into Clear Lake by transportation on recreational boats. The mussels reproduce quickly, disrupting the ecosystem, and have the potential to clog drinking water intakes and motor boat engines, and litter beaches with jagged, foul smelling shells. Figure 4-14 is an example of mussels clogging a pipe.

Lake County Public Review Draft 4-41 Local Hazard Mitigation Plan Update January 2018 Figure 4-14 Mussels Clogging a Pipe

Source: Don Schloesser, USGS, Biological Resources Division

Past Occurrences

Disaster Declaration History

There have been no federal or state disaster declarations from aquatic biological hazards.

NCDC Events

The NCDC does not track aquatic biologic hazards.

Hazard Mitigation Planning Committee Events

There have been no past occurrences of these mussels in the County, according to the HMPC. Figure 4-15 illustrates the Quagga and Zebra mussel sightings in California as of May 2012. Most of the mussel sightings are in Southern California. No mussel sightings have been officially detected in Clear Lake. The nearest infected body of water to Clear Lake was reported in 2008 in the San Justo Lake located in San Benito County, California, about three miles southwest of Hollister. According to Lake County Water Resources Department and Lake County Special Districts, quagga and zebra mussels loom as potential problems in Clear Lake.

Lake County Public Review Draft 4-42 Local Hazard Mitigation Plan Update January 2018 Figure 4-15 Quagga and Zebra Mussel Sightings in California

Source: Final Clear Lake Watershed Sanitary Survey 2012 Update

Lake County Public Review Draft 4-43 Local Hazard Mitigation Plan Update January 2018 Likelihood of Future Occurrences

Likely – The use of motor boats and registered watercraft can inadvertently continue to degrade water quality. Quagga and/or Zebra mussels can enter into Clear Lake through transport on visiting or local watercraft. Should these mussels become established in Clear Lake, they would represent a potentially significant cost to water utilities as they have to similar water districts across the nation. If these mussels infect Clear Lake there will be an increased risk of contaminating water-bodies downstream similar to how the Colorado River served as a carrier to Southern California. According to the 100th Meridian Initiative no practical technologies or biocides are available to remove these mussels once entered into a water body. As a result preventing infected boats from entering Clear Lake appears to be the only countermeasure. However, any proposed countermeasures to prevent contaminated boats or restricting boat use from entering Clear Lake could affect the local economy and as a result should be considered carefully.

4.2.8. Climate Change

Hazard/Problem Description

Climate change is the distinct change in measures of weather patterns over a long period of time, ranging from decades to millions of years. More specifically, it may be a change in average weather conditions such as temperature, rainfall, snow, ocean and atmospheric circulation, or in the distribution of weather around the average. While the Earth’s climate has cycled over its 4.5-billion-year age, these natural cycles have taken place gradually over millennia, and the Holocene, the most recent epoch in which human civilization developed, has been characterized by a highly stable climate – until recently.

This LHMP is concerned with human-induced climate change that has been rapidly warming the Earth at rates unprecedented in the last 1,000 years. Since industrialization began in the 19th century, the burning of fossil fuels (coal, oil, and natural gas) at escalating quantities has released vast amounts of carbon dioxide and other greenhouse gases responsible for trapping heat in the atmosphere, increasing the average temperature of the Earth. Secondary impacts include changes in precipitation patterns, the global water cycle, melting glaciers and ice caps, and rising sea levels. According to the Intergovernmental Panel on Climate Change (IPCC), climate change will “increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems” if unchecked.

Through changes to oceanic and atmospheric circulation cycles and increasing heat, climate change affects weather systems around the world. Climate change increases the likelihood and exacerbates the severity of extreme weather – more frequent or intense storms, floods, droughts, and heat waves. Consequences for human society include loss of life and injury, damaged infrastructure, long-term health effects, loss of agricultural crops, disrupted transport and freight, and more. Climate change is not a discrete event but a long-term hazard, the effects of which communities are already experiencing.

Climate change adaptation is a key priority of the State of California. The 2013 State of California Multi- Hazard Mitigation Plan stated that climate change is already affecting California. Sea levels have risen by as much as seven inches along the California coast over the last century, increasing erosion and pressure on the state’s infrastructure, water supplies, and natural resources. The State has also seen increased average temperatures, more extreme hot days, fewer cold nights, a lengthening of the growing season, shifts

Lake County Public Review Draft 4-44 Local Hazard Mitigation Plan Update January 2018 in the water cycle with less winter precipitation falling as snow, and earlier runoff of both snowmelt and rainwater in the year. In addition to changes in average temperatures, sea level, and precipitation patterns, the intensity of extreme weather events is also changing.

In Lake County, the HMPC noted that each year it seems to get a bit warmer and snow seems to start at higher levels. It was also noted that 2017 was one of the wettest years ever. California’s Adaptation Planning Guide: Understanding Regional Characteristics has divided California into 11 different regions based on political boundaries, projected climate impacts, existing environmental setting, socioeconomic factors and regional designations. Lake County falls within the North Coast Region characterized as a sparsely settled region where the region’s economy is primarily tourism and agriculturally-based. In addition, the North Coast is home to sandy beaches and several estuaries that support rich biodiversity. Due to varied terrain, it is also home to several microclimates and distinct ecosystems. Table 4-20 provides a summary of Cal-Adapt Climate Projections for the North Coast Region.

Table 4-20 Lake County – Cal Adapt Climate Projections

Effect Ranges Temperature January increase in average temperatures: 2°F by 2050 and up to 5°F by 2100. July increase in average Change, temperatures: 3°F by 2050 and up to 6°F by 2100 (Modeled average temperatures; high emissions 1990-2100 scenario) Precipitation Annual precipitation varies by location with a subtle decrease throughout the century in most areas. Areas of heavy rainfall (80 inches or more) are projected to lose 5 to 7 inches by 2050 and 11 to 15 inches by the end of the century. Slightly drier places are projected to see a decrease of around 3 to 4 inches by 2050 and 6 inches of precipitation by 2100. (CCSM3 climate model; high carbon emissions scenario) Heat wave Heat wave is defined as five consecutive days over 68°F over most of the coastal areas and as high as 93°F in some inland areas to the south. Little change is expected by 2050 with possibly one to three more heat waves projected in region. By 2100, projected heat waves are more variable. Along much of the coast eight to 15 more heat waves than currently occur are projected. Inland it is variable, but generally lower, between two and eight more waves per year. Snowpack March snow levels in the eastern, higher-elevation portion of the region will drop to almost zero by the 2090s, a decrease of 2 to 10 inches from 2010 levels. In areas with more snow, 3 to 5 inches of reduction will occur by 2050. In areas with currently little snow (<3 inches), the snowpack is projected to be near zero by 2050. (CCSM3 climate model; high carbon emissions scenario) Wildfire Substantial increase in fire risk is expected throughout the region. Modest increases in area burned are projected for 2050. By 2100, the projected frequency increases dramatically. Lake County is projected to have up to 2.5 times greater wildfire frequency. (GFDL climate model; high carbon emissions scenario) Source: Cal-Adapt

Past Occurrences

Disaster Declaration History

Climate change has never been directly linked to any declared disasters.

NCDC Events

The NCDC does not track climate change events. Lake County Public Review Draft 4-45 Local Hazard Mitigation Plan Update January 2018 Hazard Mitigation Planning Committee Events

CAN THE COUNTY PROVIDE ANY INPUT ON NOTABLE IMPACTS TO THE COUNTY FROM CLIMATE CHANGE?

Likelihood of Future Occurrence

Highly Likely – Climate change is virtually certain to continue without immediate and effective global action. According to NASA, 2016 was on track to be the hottest year on record, and 15 of the 17 hottest years ever have occurred since 2000. Without significant global action to reduce greenhouse gas emissions, the IPCC concludes in its Fifth Assessment Synthesis Report (2014) that average global temperatures is likely to exceed 1.5 C by the end of the 21st century, with consequences for people, assets, economies and ecosystems, including risks from heat stress, storms and extreme precipitation, inland and coastal flooding, landslides, air pollution, drought, water scarcity, sea level rise and storm surges.

Climate Scenarios

The United Nations IPCC developed several greenhouse gas (GHG) emissions scenarios based on differing sets of assumptions about future economic growth, population growth, fossil fuel use, and other factors. The emissions scenarios range from “business-as-usual” (i.e., minimal change in the current emissions trends) to more progressive (i.e., international leaders implement aggressive emissions reductions policies). Each of these scenarios leads to a corresponding GHG concentration, which is then used in climate models to examine how the climate may react to varying levels of GHGs. Climate researchers use many global climate models to assess the potential changes in climate due to increased GHGs.

Key Uncertainties Associated with Climate Projections

➢ Climate projections and impacts, like other types of research about future conditions, are characterized by uncertainty. Climate projection uncertainties include but are not limited to: ✓ Levels of future greenhouse gas concentrations and other radiatively important gases and aerosols, ✓ Sensitivity of the climate system to greenhouse gas concentrations and other radiatively important gases and aerosols, ✓ Inherent climate variability, and ✓ Changes in local physical processes (such as afternoon sea breezes) that are not captured by global climate models.

Even though precise quantitative climate projections at the local scale are characterized by uncertainties, the information provided can help identify the potential risks associated with climate variability/climate change and support long term mitigation and adaptation planning.

The following maps (shown in and) are excerpts from the Global Climate Change Impacts report that show the magnitude of the observed and projected changes in annual average temperature. It is important to discuss these projected temperature changes, as heat is a major driver of climate and climate related phenomena. The map for the period around 2000 shows that most areas of the United States have warmed 1 to 2°F compared to the 1960s and 1970s. Although not reflected in these maps of annual average temperature, this warming has generally resulted in longer warm seasons and shorter, less intense cold

Lake County Public Review Draft 4-46 Local Hazard Mitigation Plan Update January 2018 seasons. The average warming for the country as a whole is shown on the thermometers adjacent to each map. By the end of the century, the average U.S. temperature is projected to increase by approximately 7 to 11°F under the higher emissions scenario and by approximately 4 to 6.5°F under the lower emissions scenario.

Maps show projected change in average surface air temperature in the later part of this century (2071-2099) relative to the later part of the last century (1970-1999) under a scenario that assumes substantial reductions in heat trapping gases and a higher emissions scenario that assumes continued increases in global emissions. These are shown in Figure 4-16.

Figure 4-16 Projected Temperature Change – Lower and Higher Emissions Scenario

Source: National Climate Assessment

According to the California Natural Resource Agency (CNRA), climate change is already affecting California and is projected to continue to do so well into the foreseeable future. Current and projected changes include increased temperatures, sea level rise, a reduced winter snowpack altered precipitation patterns, and more frequent storm events. Over the long term, reducing greenhouse gases can help make these changes less severe, but the changes cannot be avoided entirely. Unavoidable climate impacts can result in a variety of secondary consequences including detrimental impacts on human health and safety, economic continuity, ecosystem integrity and provision of basic services.

The CNRA’s 2014 Climate Adaptation Strategy (CAS) delineated how climate change may impact and exacerbate natural hazards in the future, including wildfires, extreme heat, floods, and drought.:

➢ Climate change is expected to lead to increases in the frequency, intensity, and duration of extreme heat events and heat waves in Lake County and the rest of California, which are likely to increase the risk of mortality and morbidity due to heat-related illness and exacerbation of existing chronic health conditions. Those most at risk and vulnerable to climate-related illness are the elderly, individuals with

Lake County Public Review Draft 4-47 Local Hazard Mitigation Plan Update January 2018 chronic conditions such as heart and lung disease, diabetes, and mental illnesses, infants, the socially or economically disadvantaged, and those who work outdoors. ➢ Higher temperatures will melt the Sierra snowpack earlier and drive the snowline higher, resulting in less snowpack to supply water to California users. ➢ Droughts are likely to become more frequent and persistent in the 21st century. ➢ Intense rainfall events, periodically ones with larger than historical runoff, will continue to affect California with more frequent and/or more extensive flooding. ➢ Storms and snowmelt may coincide and produce higher winter runoff from the landward side, while accelerating sea-level rise will produce higher storm surges during coastal storms. Together, these changes may increase the probability of floods and levee and dam failures, along with creating issues related to salt water intrusion. ➢ Warmer weather, reduced snowpack, and earlier snowmelt can be expected to increase wildfire through fuel hazards and ignition risks. These changes can also increase plant moisture stress and insect populations, both of which affect forest health and reduce forest resilience to wildfires. An increase in wildfire intensity and extent will increase public safety risks, property damage, fire suppression and emergency response costs to government, watershed and water quality impacts, vegetation conversions and habitat fragmentation.

4.2.9. Dam Failure

Hazard/Problem Description

Dams are manmade structures built for a variety of uses including flood protection, power generation, agriculture, water supply, and recreation. When dams are constructed for flood protection, they are usually engineered to withstand a flood with a computed risk of occurrence. For example, a dam may be designed to contain a flood at a location on a stream that has a certain probability of occurring in any one year. If prolonged periods of rainfall and flooding occur that exceed the design requirements, that structure may be overtopped or fail. Overtopping is the primary cause of earthen dam failure in the United States.

Dam failures can also result from any one or a combination of the following causes:

➢ Earthquake; ➢ Inadequate spillway capacity resulting in excess overtopping flows; ➢ Internal erosion caused by embankment or foundation leakage, or piping or rodent activity; ➢ Improper design; ➢ Improper maintenance; ➢ Negligent operation; and/or ➢ Failure of upstream dams on the same waterway.

Water released by a failed dam generates tremendous energy and can cause a flood that is catastrophic to life and property. A catastrophic dam failure could challenge local response capabilities and require evacuations to save lives. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Major loss of life could result as well as potentially catastrophic effects to roads, bridges, and homes. Electric generating facilities and transmission lines could also be damaged and affect life support systems in communities outside the immediate hazard area. Associated water supply, water quality and health concerns could also be an issue. Factors that influence the potential severity of a

Lake County Public Review Draft 4-48 Local Hazard Mitigation Plan Update January 2018 full or partial dam failure are the amount of water impounded; the density, type, and value of development and infrastructure located downstream; and the speed of failure.

In general, there are three types of dams: concrete arch or hydraulic fill, earth and rockfill, and concrete gravity. Each type of dam has different failure characteristics. A concrete arch or hydraulic fill dam can fail almost instantaneously; the flood wave builds up rapidly to a peak then gradually declines. An earth- rockfill dam fails gradually due to erosion of the breach; a flood wave will build gradually to a peak and then decline until the reservoir is empty. And, a concrete gravity dam can fail instantaneously or gradually with a corresponding buildup and decline of the flood wave.

The California Department of Water Resources (Cal DWR) Division of Safety of Dams has jurisdiction over impoundments that meet certain capacity and height criteria. Embankments that are less than six feet high and impoundments that can store less than 15 acre-feet are non-jurisdictional. Additionally, dams that are less than 25 feet high can impound up to 50 acre-feet without being jurisdictional. Cal DWR, Division of Safety of Dams assigns hazard ratings to large dams within the State. The following two factors are considered when assigning hazard ratings: existing land use and land use controls (zoning) downstream of the dam. Dams are classified in three categories that identify the potential hazard to life and property:

➢ High hazard indicates that a failure would most probably result in the loss of life ➢ Significant hazard indicates that a failure could result in appreciable property damage ➢ Low hazard indicates that failure would result in only minimal property damage and loss of life is unlikely

According to data provided by Lake County, Cal DWR, and Cal OES, there are 21 dams of concern to Lake County that were constructed for flood control, storage, treatment impoundments, electrical generation, and recreational purposes. Of the 21 dams, 11 are rated as High Hazard, 4 as Significant Hazard, 6 as Low Hazard. Figure 4-17 identifies the 21 dams located in the Lake County Planning Area.

Lake County Public Review Draft 4-49 Local Hazard Mitigation Plan Update January 2018 Figure 4-17 Lake County Dam Inventory

Lake County Public Review Draft 4-50 Local Hazard Mitigation Plan Update January 2018 Table 4-21 Lake County Dam Inventory

Owner Maximum EAP Hazard Dam Structural Storage Name Classification Type River/Stream Height (ft) (acre-ft) Adobe Creek Lake County High Rockfill Adobe Creek 36 695 Not Watershed reported Protection District Allen Richard and Significant Rockfill Tr Kelsey Cr 33 85 Not Wendy reported Reynolds Bar X Ranch Heart High Rockfill Crazy Creek 30 147 Not Reservoir # 2 Consciousness reported Church Bordeaux, Langtry Low Rockfill Tr Bucksnort 42 538 Not Lake Farms, LLC Creek reported Bottoms Middletown High Rockfill Tr Helena 47 315 Not Enterprises Creek reported Burgundy, Langtry Low Rockfill Tr Bucksnort 27 200 Not Lake Farms, LLC Creek reported Cache Creek Yolo County High Gravity Cache Creek 35 320,000 Y Flood Control and Water Conservation District Coyote Creek Hidden Valley High Rockfill Coyote Creek 92 3,375 Not Lake reported Association Graham Sue Low Rockfill Tr Highland 39 62 Not Thomason Cr reported Guenoc Lake Langtry Significant Rockfill Bucksnort 50 3,237 Not Farms, LLC Creek reported Highland Lake County High Rockfill Highland 76 3,500 Y Creek Watershed Creek Protection District Homestake Homestake High Rockfill Tr Hunting Cr 171 0.4 Y Tailings Mining Company Indian Valley Yolo County High Earth North Fork 210 261,000 Y Flood Control Cache Creek and Water Conservation District Lake Co San Lake County Significant Rockfill Tr Burns Val 40 530 Not Dist Sanitation Creek reported District

Lake County Public Review Draft 4-51 Local Hazard Mitigation Plan Update January 2018 Owner Maximum EAP Hazard Dam Structural Storage Name Classification Type River/Stream Height (ft) (acre-ft) Lake Co San Lake County High Rockfill Tr Lyons 78 870 Not Dist 2 Sanitation Creek reported District Lakeport City of High Rockfill Tr Manning Cr 51 650 Not Lakeport reported Municipal Sewer District Number 1 Langtry Langtry Low Rockfill Tr Cassidy 50 525 Not Farms, LLC Creek reported Mccreary Langtry Low Rockfill Bucksnort 20 2,100 Not Farms, LLC Creek reported Peters Stephen Low Rockfill Benmore 33 112 Not Cowan Creek reported Scott Pacific Gas High Gravity Eel River 135 80,600 Y and Electric Company Spring Valley County of Significant Rockfill Wolf Creek 37 325 Not Lake reported Source: Cal OES and the National Performance of Dams Program *One Acre Foot=326,000 gallons

Dam failure is a natural disaster from two perspectives. First, the inundation from released waters resulting from dam failure is related to naturally occurring floodwaters. Second, dam failure would most probably happen in consequence of the natural disaster triggering the event. M any bodies of water located in Lake County are man-created reservoirs. Some of the reservoirs only slightly raise the water level of the lake behind them. Indian Valley Reservoir is the county’s largest man-made lake in size, storing over 359,000 acre-feet. A large number of small reservoirs within the county harness agriculture waters that were created solely by the dam’s construction.

Most dams in Lake County are removed from the population clusters. The remote locations of the dam’s shields residences from the potential hazards associated with dam failure and resulting inundation. There are three exceptions to this, Indian Valley Reservoir, Coyote Creek Dam and the effluent storage reservoir at the Southeast Wastewater Treatment Plant. The County has nine dams of concern.

➢ Cache Creek ➢ Scott Dam ➢ Indian Valley ➢ Coyote Creek ➢ Highland Creek ➢ Adobe Creek ➢ Northwest Wastewater Treatment Plan ➢ Southeast Wastewater Treatment Plant ➢ Lakeport Wastewater Treatment Plant

Lake County Public Review Draft 4-52 Local Hazard Mitigation Plan Update January 2018 These are discussed below.

Cache Creek

The Cache Creek Dam is located 3.5 miles downstream of the outlet from Clear Lake. The dam is a concrete, gravity-type structure. This dam is owned and operated by Yolo County Flood Control and Water Conservation District (YCFCWCD). The relationship between Clear Lake and the dam is unique in that the dam does not control maximum overflows from Clear Lake. The Grigsby Riffle located near Lake Street between Clear Lake and the dam controls maximum outflows. Because of this unique relationship, there are two separate failure scenarios:

➢ Winter Failure: When the lake is above 7.56 feet Rumsey (full), the dam is releasing flows at the channel capacity and there is little water stored behind the dam. Catastrophic dam failure under these conditions would result in a minimal flood wave downstream. ➢ Sunny Day Failure: A sunny day failure would be the most severe if Clear Lake is full and there are minimal releases from the dam. Catastrophic failure of the dam would release all the water stored between the dam and the Grigsby Riffle, causing a significant flood wave (8 to 18 feet high) through the Cache Creek Canyon. At this elevation, flows from Clear Lake would be limited to approximately 2,500 cfs by the Grigsby Riffle. The flood wave would be mitigated to insignificant levels by the storage pool at the Capay Diversion Dam.

No communities below the Cache Creek Dam would be flooded by a dam failure. The primary concern would be persons using the creek area for recreational purposes, which could include rafting, kayaking, fishing or using low lying areas adjacent to the creek. If the lake level is still high, failure of the dam could cause significant property damage along Cache Creek above the dam, as water levels would drop rapidly between the Dam and the Grigsby Riffle causing bank and retaining wall failures, and destruction of many of the docks within Cache Creek, followed by high flow velocities as the Clear Lake drained to the level of the Grigsby Riffle.

Scott Dam

Scott Dam is located on the upper Eel River in the Mendocino National Forest. It can be reached through Potter Valley, Mendocino County or Elk Mountain Road from Upper Lake. Dam failure inundation zones include Mendocino County communities, and the Cities of Rio Dell, Fortuna and Ferndale in Humboldt County to the Pacific Ocean. The dam is owned and operated by Pacific Gas & Electric (PG&E). Scott Dam is the second largest dam in Lake County, located at the western edge of Lake Pillsbury. Failure of this dam would result in potential damage to life and property at Soda Creek Station, PG&E campsites along the Eel River, and catastrophic damage to life and property in neighboring Mendocino County and further north into Humboldt County. Residents of Lake Pillsbury area would be isolated due to damaged roads. Emergency planning considerations would be to conduct air evacuation from rural Gravelly Airport. Emergency management considerations would be to provide assistance to other counties.

Indian Valley

Indian Valley Dam is located approximately 5 miles north of State Highway 20 between Clear Lake and Williams. It can be reached by Walker Ridge Road. The dam is an earthen structure, and is the largest dam

Lake County Public Review Draft 4-53 Local Hazard Mitigation Plan Update January 2018 in Lake County. The dam is owned and operated by the Yolo County Flood Control and Water Conservation District. Failure of this dam would result in flooding. The primary area of concern is the Spring Valley development where residents are located in the inundation zone. There are 210 residential structures subject to flooding in Lake County due to dam failure. The potential exists for the washout of New Long Valley Road and State Highway 20, which would isolate and trap numerous residences. Other evacuation concerns would be for seasonal population along Cache Creek and vehicular traffic on State Highway 20. Catastrophic damage would be experienced downstream to Yolo County communities.

Coyote Creek

Coyote Creek Dam is located east of Highway 29, between the communities of Lower Lake and Middletown at the Hidden Valley Lake residential area. Coyote Creek Dam is owned and operated by the Hidden Valley Lake Association. The dam is an earthen structure. Failure of the dam would cause extensive property damage to residential structures, an Elementary School, commercial buildings, a golf course and State Highway 29.

Highland Creek

Highland Creek Dam is located approximately 0.5 miles west of Adobe Creek Dam. The dam can be reached on Highland Springs Road, Bell Hill Road or the Old Toll Road. The dam is an earthen structure. The dam is owned and operated by the Lake County Watershed Protection District. Dam failure inundation zones include Adobe Creek areas south of State Highway 29. Failure of the dam would result in extensive property damage to residential structures and agricultural properties along Adobe Creek.

Adobe Creek

Adobe Creek Dam is located approximately 5 miles south of Finley. It can be reached from State Highway 29 by the Highlands Springs turn-off on Bell Hill Road near Kelseyville or from Hopland in Mendocino County via Old Toll Road. Adobe Dam is an earthen structure. Lake County Watershed Protection District is the Owner and Operator of the dam. Dam failure inundation zones include Adobe Creek areas south of State Highway 29. Failure of the dam would result in extensive property damage to residential structures and agricultural properties along Adobe Creek.

Northwest Wastewater Treatment Plan

Northwest Wastewater Treatment Plant is located approximately 5 miles north northwest of the City of Lakeport. It can be reached from Highway 29 at the Nice/Lucerne cutoff. Northwest Wastewater Treatment Plant Reservoir is an earthen structure. Lake County Special District is the Owner and Operator of the reservoir. Failure of the dam would result in extensive property damage to residential structures, juvenile hall facility and agricultural properties along Waylan Way and Hill Road.

Southeast Wastewater Treatment Plant

Southeast Wastewater Treatment Plant is located approximately 1.5 miles north of the City of Clearlake. It can be reached from State Highway 53 by the north Old Highway 53 turn-off and then on to Pond Road. Southeast Wastewater Treatment Plant Reservoir is an earthen structure. Lake County Special District is

Lake County Public Review Draft 4-54 Local Hazard Mitigation Plan Update January 2018 the Owner and Operator of the reservoir. Failure of the dam would result in extensive property damage to residential structures along Pond Road, areas of Old Hwy 53 and Rumsey Road.

Lakeport Wastewater Treatment Plant

Lakeport Wastewater Treatment Plant is located approximately 1 mile southwest of the City of Lakeport. It can be reached from Highway 29/175 intersection. Lakeport Wastewater Treatment Plant Reservoir is an earthen structure. City of Lakeport is the Owner and Operator of the reservoir. Failure of the dam would result in extensive property damage to residential structures and agricultural properties along Linda Lane in Lakeport.

Past Occurrences

Disaster Declaration History

There have been no disasters declarations related to dam failure in Lake County.

NCDC Events

There have been no NCDC dam failure events in Lake County.

NPDP Events

The National Performance of Dams Program at Stanford University tracks dam failures. A search of the National Performance of Dams Program database showed no past dam failure events in Lake County.

Hazard Mitigation Planning Committee Events

According to the HMPC, there has never been a major dam failure in Lake County. There have been two agricultural reservoirs that have failed in Lake County over the past 28 years. DETAILS ON THESE? FROM PREVIOUS PLAN.

The HMPC also indicated that the Cache Creek dam, while not failing, had an issue in 2012 when the release gate jammed contributing to extended releases and flooding.

Also identified by the HMPC, a past landslide is evident downstream of the Indian Valley Reservoir dam which resulted in a debris impediment upstream of the Spring Valley subdivision. This landslide area, with limited access, may contribute to future flow issues within this area.

In addition, the HMPC noted that a Kelsey Creek concrete structure that is no longer in service that could potentially impede flows.

Likelihood of Future Occurrence

Occasional—The County remains at risk to dam breaches/failures from numerous dams under a variety of ownership and control and of varying ages and conditions. Although, there is no history of past dam failures, given the number and types of dams in the County and their ages, a potential exists for future dam

Lake County Public Review Draft 4-55 Local Hazard Mitigation Plan Update January 2018 issues, including failures, in the Lake County Planning Area. Thus, the HMPC determined the likelihood of future occurrence to be occasional. In addition to the aging dam infrastructure, this ranking was based on the recent issues with the nearby Oroville dam, that was at risk of overtopping and failure during the Winter 2017 storms. There is concern that many of the State’s older dams, including those in Lake County, could start experiencing similar problems.

Climate Change and Dam Failure

Increases in both precipitation and heat causing snow melt could increase the potential for dam failure and uncontrolled releases in Lake County.

4.2.10. Drought and Water Shortage

Hazard/Problem Description

Drought

Drought is a gradual phenomenon. Although droughts are sometimes characterized as emergencies, they differ from typical emergency events. Most natural disasters, such as floods or forest fires, occur relatively rapidly and afford little time for preparing for disaster response. Droughts occur slowly, over a multi-year period, and it is often not obvious or easy to quantify when a drought begins and ends. Water districts normally require at least a 10-year planning horizon to implement a multiagency improvement project to mitigate the effects of a drought and water supply shortage.

Drought is a complex issue involving (see Figure 4-18) many factors—it occurs when a normal amount of precipitation and snow is not available to satisfy an area’s usual water-consuming activities. Drought can often be defined regionally based on its effects:

➢ Meteorological drought is usually defined by a period of below average water supply. ➢ Agricultural drought occurs when there is an inadequate water supply to meet the needs of the state’s crops and other agricultural operations such as livestock. ➢ Hydrological drought is defined as deficiencies in surface and subsurface water supplies. It is generally measured as streamflow, snowpack, and as lake, reservoir, and groundwater levels. ➢ Socioeconomic drought occurs when a drought impacts health, well-being, and quality of life, or when a drought starts to have an adverse economic impact on a region.

Lake County Public Review Draft 4-56 Local Hazard Mitigation Plan Update January 2018 Figure 4-18 Causes and Impact of Drought

Source: National Drought Mitigation Center

Drought in the United States is monitored by the National Integrated Drought Information System (NIDIS). A major component of this portal is the U.S. Drought Monitor. The Drought Monitor concept was developed jointly by the NOAA’s Climate Prediction Center, the NDMC, and the USDA’s Joint Agricultural Weather Facility in the late 1990s as a process that synthesizes multiple indices, outlooks and local impacts, into an assessment that best represents current drought conditions. The final outcome of each Drought Monitor is a consensus of federal, state, and academic scientists who are intimately familiar with the conditions in their respective regions. A snapshot of the drought conditions in California and the Planning Area can be found in Figure 4-19. A snapshot from 2015 and 2016 is shown in Figure 4-20.

Lake County Public Review Draft 4-57 Local Hazard Mitigation Plan Update January 2018 Figure 4-19 Current Drought Status in Lake County

Source: US Drought Monitor

Figure 4-20 Previous Drought Status in Lake County

Source: US Drought Monitor

Lake County Public Review Draft 4-58 Local Hazard Mitigation Plan Update January 2018 The California Department of Water Resources (DWR) says the following about drought:

One dry year does not normally constitute a drought in California. California’s extensive system of water supply infrastructure—its reservoirs, groundwater basins, and inter-regional conveyance facilities—mitigates the effect of short-term dry periods for most water users. Defining when a drought begins is a function of drought impacts to water users. Hydrologic conditions constituting a drought for water users in one location may not constitute a drought for water users elsewhere, or for water users having a different water supply. Individual water suppliers may use criteria such as rainfall/runoff, amount of water in storage, or expected supply from a water wholesaler to define their water supply conditions.

The drought issue in California is further compounded by water rights. Water is a commodity possessed under a variety of legal doctrines. The prioritization of water rights between farming and federally protected fish habitats in California contributes to this issue.

Drought is not initially recognized as a problem because it normally originates in what is considered good weather, which typically includes a dry late spring and summer in Mediterranean climates, such as in California. This is particularly true in Northern California where drought impacts are delayed for most of the population by the wealth of stored surface and ground water. The drought complications normally appear more than a year after a drought begins. In most areas of California, ranchers that rely on rainfall to support forage for their livestock are the earliest and most affected by drought. Even below normal water years could affect ranchers depending on the timing and duration of precipitation events. It is difficult to quantitatively assess drought impacts to Lake County because not many county-specific studies have been conducted. Some factors to consider include the impacts of fallowed agricultural land, habitat loss and associated effects on wildlife, and the drawdown of the groundwater table. The most direct and likely most difficult drought impact to quantify is to local economies, especially agricultural economies. The State has conducted some empirical studies on the economic effects of fallowed lands with regard to water purchased by the State’s Water Bank; but these studies do not quantitatively address the situation in Lake County. It can be assumed, however, that the loss of production in one sector of the economy would affect other sectors.

The drawdown of the groundwater table is one factor that has been recognized to occur during repeated dry years. Lowering of groundwater levels results in the need to deepen wells, which subsequently lead to increased pumping costs. These costs are a major consideration for residents relying on domestic wells and agricultural producers that irrigate with groundwater and/or use it for frost protection. Some communities in higher elevations with shallow bedrock do not have a significant source of groundwater.

Drought impacts are wide-reaching and may be economic, environmental, and/or societal. The most significant impacts associated with drought in the Planning Area are those related to water intensive activities such as agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. Also, during a drought, allocations go down and water costs increase, which results in reduced water availability. Voluntary conservation measures are a normal and ongoing part of system operations and actively implemented during extended droughts. A reduction of electric power generation and water quality deterioration are also potential problems. Drought conditions can also cause soil to compact and not absorb water well, potentially making an area more susceptible to flooding and erosion.

Lake County Public Review Draft 4-59 Local Hazard Mitigation Plan Update January 2018 Water Shortage

Northern Sacramento Valley counties, including Lake County, generally have sufficient groundwater and surface water supplies to mitigate even the severest droughts of the past century. Many other areas of the State, however, also place demands on these water resources during severe drought. For example, Northern California agencies, including those from Lake County, were major participants in the Governor’s Drought Water Bank of 1991, 1992, and 1994. The HMPC noted the County utilizes mostly groundwater, with many residents on wells; thus, there is a smaller impact in Lake County compared to other areas more dependent on surface water sources. Surface water is also used in the County, but to a lesser extent than groundwater.

Past Occurrences

Disaster Declaration History

There has been two state disaster related to drought and water shortage in Lake County issued in 1977 and 2014. This can be seen in Table 4-22.

Table 4-22 Lake County – Disaster Declarations from Drought 1950-2017

Disaster Type Federal Declarations State Declarations Count Years Count Years Drought 0 – 2 1977, 2014 Source: FEMA, Cal OES

2014 Governor’s Drought Declaration

California’s ongoing response to its five-year drought has been guided by a series of executive orders issued by Governor Edmund G. Brown Jr. that are listed below beginning with the most recent and continuing in reverse chronological order:

➢ Executive Order B-37-16, May 9, 2016: The Governor’s latest drought-related executive order established a new water use efficiency framework for California. The order bolstered the state’s drought resilience and preparedness by establishing longer-term water conservation measures that include permanent monthly water use reporting, new urban water use targets, reducing system leaks and eliminating clearly wasteful practices, strengthening urban drought contingency plans and improving agricultural water management and drought plans. ➢ Executive Order B-36-15, November 13, 2015: This executive order called for additional actions to build on the State’s ongoing response to record dry conditions and assist recovery efforts from 2015’s devastating wildfires. ➢ Executive Order B-29-15, April 1, 2015: Key provisions included ordering the State Water Resources Control Board (Board) to impose restrictions to achieve a 25-percent reduction in potable urban water usage through February 28, 2016; directing the California Department of Water Resources (DWR) to lead a statewide initiative, in partnership with local agencies, to collectively replace 50 million square feet of lawns and ornamental turf with drought tolerant landscapes, and directing the California Energy

Lake County Public Review Draft 4-60 Local Hazard Mitigation Plan Update January 2018 Commission to implement a statewide appliance rebate program to provide monetary incentives for the replacement of inefficient household devices. ➢ Executive Order B-28-14, December 22, 2014: The order cited paragraph 9 of the January 17, 2014 Proclamation and paragraph 19 of the April 25, 2014 Proclamation (both are linked below) and extended the operation of the provisions in these paragraphs through May 31, 2016. ➢ Executive Order B-27-14, October 6, 2014: The order directed State agencies to assist local governments in their response to wildfires during California’s drought conditions. ➢ Executive Order B-26-14, September 18, 2014: The order facilitated efforts to provide water to families in dire need as extreme drought continued throughout California. ➢ Proclamation of a Continued State of Emergency, April 25, 2014: The order strengthened the State’s ability to manage water and habitat effectively in drought conditions and called on all Californians to redouble their efforts to conserve water. ➢ Drought State of Emergency, January 17, 2014: The Governor proclaimed a State of Emergency and directed State officials to take all necessary actions to make water immediately available. Key measures in the proclamation included: ✓ Asking all Californians to reduce water consumption by 20 percent and referring residents and water agencies to the Save Our Water campaign – www.saveourwater.com – for practical advice on how to do so; ✓ Directing local water suppliers to immediately implement local water shortage contingency plans; ✓ Ordering the Board to consider petitions for consolidation of places of use for the State Water Project and Central Valley Project, which could streamline water transfers and exchanges between water users; ✓ Directing DWR and the Board to accelerate funding for projects that could break ground in 2014 and enhance water supplies; ✓ Ordering the Board to put water rights holders across the state on notice that they may be directed to cease or reduce water diversions based on water shortages; ✓ Asking the Board to consider modifying requirements for releases of water from reservoirs or diversion limitations so that water may be conserved in reservoirs to protect cold water supplies for salmon, maintain water supplies and improve water quality.

NCDC Events

There have been 15 NCDC drought events in Lake County. All of these were for the 2014-2016 drought, but no damages, injuries, or losses were reported in the NCDC database.

Hazard Mitigation Planning Committee Events

Historically, California has experienced multiple severe droughts. According to the DWR, droughts exceeding three years are relatively rare in Northern California, the source of much of the State’s developed water supply. The 1929-34 drought established the criteria commonly used in designing storage capacity and yield of large northern California reservoirs. Table 4-23 compares the 1929-34 drought in the Sacramento and San Joaquin Valleys to the 1976-77, 1987-92, and 2007-09 droughts. Figure 4-21 depicts California’s Multi-Year Historical Dry Periods, 1850-2000.

Lake County Public Review Draft 4-61 Local Hazard Mitigation Plan Update January 2018 Table 4-23 Severity of Extreme Droughts in the Sacramento and San Joaquin Valleys

Sacramento Valley Runoff San Joaquin Valley Runoff Drought Period (maf*/yr) (percent Average 1901-96) (maf*/yr) (percent Average 1906-96) 1929-34 9.8 55 3.3 57 1976-77 6.6 37 1.5 26 1987-92 10.0 56 2.8 47 2007-09 11.2 64 3.7 61 Source: California’s Drought of 2007-2009, An Overview. State of California Natural Resources Agency, California Department of Water Resources. Available at: http://www.water.ca.gov/drought/docs/DroughtReport2010.pdf *maf=million acre feet

Figure 4-21 California’s Multi-Year Historical Dry Periods, 1850-2000

Source: California Department of Water Resources, www.water.ca.gov/ Notes: Dry periods prior to 1900 estimated from limited data; covers dry periods of statewide or major regional extent

Figure 4-22 depicts runoff for the State from 1900 to 2015. This gives a historical context for the 2014- 2015 drought to past droughts

Figure 4-22 Annual California Runoff –1900 to 2015

Source: California DWR

The HMPC noted that during the 2014 drought that was just declared over by the California Governor in April 2017, the County experienced significant economic impacts, many associated with the recreational

Lake County Public Review Draft 4-62 Local Hazard Mitigation Plan Update January 2018 industry as well as the agricultural industry. In addition, the recent drought increased tree mortality in the County associated with both dying trees due to lack of moisture and those infected with Bark Beetle and other issues such as Sudden Oak death. Drought also compounded the wildfire risk throughout the County.

Other issues identified by the HMPC included those associated with the levels of the lake dropping during the extended drought. Specifically, the lake levels fell below water intake facilities impacting the ability to supply water to County communities. Special districts put in and ordinance; mandatory water restrictions in Cobb Mountain were 50 gallons per day per person. Most water is groundwater the larger systems are from the lake; some of the ground water systems were under mandatory moratorium for building like in Hidden Valley Lake. To help ward this off, there is discussions of consolidation of water systems in the County and put in water system interties. 8 systems on Cobb mountain are being consolidated. Changes in ordinances are needed. Some individual wells went dry, there was a fire suppression issues in that the mutual aid resources pulled water out of an area that had water but wasn’t allowed to pull water. There are no generators at the wells and no booster systems.

Water Shortage

Figure 4-23 illustrates several indicators commonly used to evaluate water conditions in California. The percent of average values are determined by measurements made in each of the ten major hydrologic regions. The chart describes water conditions in California between 2001 and 2012. The chart illustrates the cyclical nature of weather patterns in California. Snow pack and precipitation increased between 2005 and 2006, began decreasing in late 2006, and began to show signs of recovery in 2009.

Figure 4-23 Water Supply Conditions, 2001 to 2012

Source: 2013 State of California Hazard Mitigation Plan

Beginning in 2012, snowpack levels in California dropped dramatically. 2015 estimates place snowpack as 5 percent of normal levels. Snowpack measurements have been kept in California since 1950 and nothing in the historic record comes close to 2015’s severely depleted level. The previous record for the lowest snowpack level in California, 25 percent of normal, was set both in 1976-77 and 2013-2014. In “normal”

Lake County Public Review Draft 4-63 Local Hazard Mitigation Plan Update January 2018 years, the snowpack supplies about 30 percent of California’s water needs, according to the California Department of Water Resources. Snowpack levels began to increase in 2016, and in 2017 snowpack increased to the largest in 22 years, according to the State Department of Water Resources.

With a reduction in water, water supply issues based on water rights becomes more evident. Some agricultural uses, such as grapes, are severely impacted through limited water supply. Drought and water supply issues will continue to be a concern to the Planning Area. Irrigation of agricultural lands continues to be a concern in the Planning Area. Also noted by the HMPC, several areas within the County, such as the Long Valley area, had ground water wells go dry affecting water supply to County residents. EXPAND ON THIS

Likelihood of Future Occurrence

Drought

Likely—Historical drought data for the Lake County Planning Area and region indicate there have been 5 significant droughts in the last 84 years. This equates to a drought every 16.8 years on average or a 6.0 percent chance of a drought in any given year. However, based on this data and given the multi-year length of droughts, the HMPC determined that future drought occurrence in the Planning Area are likely.

Water Shortage

Occasional — Recent historical data for water shortage indicates that Lake County may at some time be at risk to both short and prolonged periods of water shortage. Based on this it is possible that water shortages will affect the County in the future during extreme drought conditions. However, to date, Lake County has continued to have relatively consistent water supply. TRUE?

Climate Change and Drought and Water Shortage

Climate scientists studying California find that drought conditions are likely to become more frequent and persistent over the 21st century due to climate change. The experiences of California during recent years underscore the need to examine more closely the state’s water storage, distribution, management, conservation, and use policies. The Climate Adaptation Strategy (CAS) stresses the need for public policy development addressing long term climate change impacts on water supplies. The CAS notes that climate change is likely to significantly diminish California’s future water supply, stating that:

California must change its water management and uses because climate change will likely create greater competition for limited water supplies needed by the environment, agriculture, and cities.

The regional implications of declining water supplies as a long‐term public policy issue are recognized in a Southern California Association of Governments July 2009 publication of essays examining climate change topics. In one essay, Dan Cayan observes:

In one form or another, many of Southern California’s climate concerns radiate from efforts to secure an adequate fresh water supply…Of all the areas of North America, Southern California’s annual receipt of precipitation is the most volatile – we only occasionally see a “normal” year, and in the last few we have swung from very wet

Lake County Public Review Draft 4-64 Local Hazard Mitigation Plan Update January 2018 in 2005 to very dry in 2007 and 2008….Southern California has special challenges because it is the most urban of the California water user regions and, regionwide, we import more than two‐thirds of the water that we consume.

Members of the HMPC noted a report published in Science magazine in 2015 that stated:

Given current greenhouse gas emissions, the chances of a 35+ year “megadrought” striking the Southwest by 2100 are above 80 percent.

The HMPC also noted a report from the Public Policy Institute of California that thousands of Californians – mostly in rural, small, disadvantaged communities – already face acute water scarcity, contaminated groundwater, or complete water loss. Climate change would make these effects worse.

4.2.11. Earthquake

Hazard/Problem Description

An earthquake is caused by a sudden slip on a fault. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up, and the rocks slip suddenly, releasing energy in waves that travel through the earth’s crust and cause the shaking that is felt during an earthquake. The amount of energy released during an earthquake is usually expressed as a magnitude and is measured directly from the earthquake as recorded on seismographs. An earthquake’s magnitude is expressed in whole numbers and decimals (e.g., 6.8). Seismologists have developed several magnitude scales. One of the first was the Richter Scale, developed in 1932 by the late Dr. Charles F. Richter of the California Institute of Technology. The Richter Magnitude Scale is used to quantify the magnitude or strength of the seismic energy released by an earthquake. Another measure of earthquake severity is intensity. Intensity is an expression of the amount of shaking at any given location on the ground surface (see Table 4-24). Seismic shaking is typically the greatest cause of losses to structures during earthquakes.

Table 4-24 Modified Mercalli Intensity (MMI) Scale

MMI Felt Intensity I Not felt except by a very few people under special conditions. Detected mostly by instruments. II Felt by a few people, especially those on upper floors of buildings. Suspended objects may swing. III Felt noticeably indoors. Standing automobiles may rock slightly. IV Felt by many people indoors; by a few outdoors. At night, some people are awakened. Dishes, windows, and doors rattle. V Felt by nearly everyone. Many people are awakened. Some dishes and windows are broken. Unstable objects are overturned. VI Felt by everyone. Many people become frightened and run outdoors. Some heavy furniture is moved. Some plaster falls. VII Most people are alarmed and run outside. Damage is negligible in buildings of good construction, considerable in buildings of poor construction. VIII Damage is slight in specially designed structures, considerable in ordinary buildings, and great in poorly built structures. Heavy furniture is overturned.

Lake County Public Review Draft 4-65 Local Hazard Mitigation Plan Update January 2018 MMI Felt Intensity IX Damage is considerable in specially designed buildings. Buildings shift from their foundations and partly collapse. Underground pipes are broken. X Some well-built wooden structures are destroyed. Most masonry structures are destroyed. The ground is badly cracked. Considerable landslides occur on steep slopes. XI Few, if any, masonry structures remain standing. Rails are bent. Broad fissures appear in the ground. XII Virtually total destruction. Waves are seen on the ground surface. Objects are thrown in the air. Source: Multi-Hazard Identification and Risk Assessment, FEMA 1997

California is seismically active because it sits on the boundary between two of the earth’s tectonic plates. Most of the state ‐ everything east of the San Andreas Fault ‐ is on the North American Plate. The cities of Monterey, Santa Barbara, Los Angeles, and San Diego are on the Pacific Plate, which is constantly moving northwest past the North American Plate. The relative rate of movement is about two inches per year. The San Andreas Fault is considered the boundary between the two plates, although some of the motion is taken up on faults as far away as central Utah.

Faults

A fault is defined as “a fracture or fracture zone in the earth’s crust along which there has been displacement of the sides relative to one another.” For the purpose of planning there are two types of faults, active and inactive. Active faults have experienced displacement in historic time, suggesting that future displacement may be expected. Inactive faults show no evidence of movement in recent geologic time, suggesting that these faults are dormant. This does not mean, however, that faults having no evidence of surface displacement within the last 11,000 years are necessarily inactive. For example, the 1975 Oroville earthquake, the 1983 Coalinga earthquake, and the 1987 Whittier Narrows earthquake occurred on faults not previously recognized as active. Potentially active faults are those that have shown displacement within the last 1.6 million years (Quaternary). An inactive fault shows no evidence of movement in historic (last 200 years) or geologic time, suggesting that these faults are dormant.

Two types of fault movement represent possible hazards to structures in the immediate vicinity of the fault: fault creep and sudden fault displacement. Fault creep, a slow movement of one side of a fault relative to the other, can cause cracking and buckling of sidewalks and foundations even without perceptible ground shaking. Sudden fault displacement occurs during an earthquake event and may result in the collapse of buildings or other structures that are found along the fault zone when fault displacement exceeds an inch or two. The only protection against damage caused directly by fault displacement is to prohibit construction in the fault zone.

The geology of the Northern California Coastal Region is distinct from the rest of California. Geologists and seismologists find the region of special interest because of the San Andreas Fault, which is within 30 miles to the west, the Hayward fault, and Rogers fault extension into the Mayacamas fault which is within 10 miles to the west of Lake County. These are the major faults in the area and are described in more detail below.

➢ The San Andreas Fault traverses the entire length of the State of California. The fault zone is located approximately 30 miles west of the Lake County line traveling the coastline of Mendocino County. The

Lake County Public Review Draft 4-66 Local Hazard Mitigation Plan Update January 2018 ground shaking of an 8.3 magnitude earthquake on the northern section of the fault would result in serious damage and loss of life to Northern California including Lake County. The maximum credible earthquake (MCE) capable of being generated along this system, which was responsible for the October 17, 1989 Loma Prieta earthquake (Richter magnitude 7.1), is 8.3 on the Richter scale. ➢ The Mayacama Fault traverses the Lake and Mendocino County lines in the eastern mountains less than 20 miles from the Clear Lake basin. The Mayacama Fault is the northern segment of the Healdsburg/Rodgers Creek Fault Zone in Sonoma County. The Healdsburg/Rodgers Creek Fault line is the northern segment of the Hayward Fault Zone traversing the eastern portion of the San Francisco Bay Area. Trenching studies across the fault by USGS have resulted in an estimated 250-year recurrence interval for magnitude 7.0 earthquakes. The last major earthquake along the Healdsburg/Rogers Fault was in 1808, and the USGS considers this fault a prime potential for future large earthquakes. The Hayward Fault Zone has a 25 percent chance of producing an earthquake of magnitude 7.0 or greater within the next 30 years, according to the California Division of Mines and Geology.

Throughout Lake County there are several small active faults, with most centered in the Cobb Mountain area. Minor earthquakes occur almost daily in the south county geothermal fields near the geysers influenced region (more information below). A major threat to the entire a Northern California region is the Mendocino Triple Junction in Humboldt County, were three plates, the Gorda, the North American, and the Pacific are in contact. The region is part of the Cascadia Subduction Zone (“CSZ”) and vulnerable to an earthquake up to the 9.0 magnitude range. The CSZ runs from the Cape Mendocino area of Humboldt County to north of Vancouver Island off British Columbia, Canada.

Figure 4-24 shows fault locations in and near Lake County.

Lake County Public Review Draft 4-67 Local Hazard Mitigation Plan Update January 2018 Figure 4-24 Active Faults in and near Lake County

Source: Lake County 2008 General Plan Lake County Public Review Draft 4-68 Local Hazard Mitigation Plan Update January 2018 Earthquake Hazards

Earthquakes can cause structural damage, injury, and loss of life, as well as damage to infrastructure networks, such as water, power, gas, communication, and transportation. Earthquakes may also cause collateral emergencies including dam and levee failures, seiches, hazmat incidents, fires, avalanches, and landslides. The degree of damage depends on many interrelated factors. Among these are: the magnitude, focal depth, distance from the causative fault, source mechanism, duration of shaking, high rock accelerations, type of surface deposits or bedrock, degree of consolidation of surface deposits, presence of high groundwater, topography, and the design, type, and quality of building construction. This section briefly discusses issues related to types of seismic hazards.

Ground Shaking

Ground shaking is motion that occurs as a result of energy released during faulting. The damage or collapse of buildings and other structures caused by ground shaking is among the most serious seismic hazards. Damage to structures from this vibration, or ground shaking, is caused by the transmission of earthquake vibrations from the ground to the structure. The intensity of shaking and its potential impact on buildings is determined by the physical characteristics of the underlying soil and rock, building materials and workmanship, earthquake magnitude and location of epicenter, and the character and duration of ground motion.

Actual ground breakage generally affects only those buildings directly over or nearby the fault. Ground shaking generally has a much greater impact over a greater geographical area than ground breakage. The amount of breakage and shaking is a function of earthquake magnitude, type of bedrock, depth and type of soil, general topography, and groundwater. As with most communities in Northern California near active faults, much of Lake County would be susceptible to violent ground shaking.

Seismic Structural Safety

Older buildings constructed before building codes were established, and even newer buildings constructed before earthquake-resistance provisions were included in the codes, are the most likely to be damaged during an earthquake. Buildings one or two stories high of wood-frame construction are considered to be the most structurally resistant to earthquake damage. Older masonry buildings without seismic reinforcement (unreinforced masonry) are the most susceptible to the type of structural failure that causes injury or death.

The susceptibility of a structure to damage from ground shaking is also related to the underlying foundation material. A foundation of rock or very firm material can intensify short-period motions which affect low- rise buildings more than tall, flexible ones. A deep layer of water-logged soft alluvium can cushion low- rise buildings, but it can also accentuate the motion in tall buildings. The amplified motion resulting from softer alluvial soils can also severely damage older masonry buildings.

Other potentially dangerous conditions include, but are not limited to: building architectural features that are not firmly anchored, such as parapets and cornices; roadways, including column and pile bents and abutments for bridges and overcrossings; and above-ground storage tanks and their mounting devices. Such features could be damaged or destroyed during strong or sustained ground shaking. Lake County Public Review Draft 4-69 Local Hazard Mitigation Plan Update January 2018 Liquefaction Potential

Liquefaction is a process whereby soil is temporarily transformed to a fluid formed during intense and prolonged ground shaking. Areas most prone to liquefaction are those that are water saturated (e.g., where the water table is less than 30 feet below the surface) and consist of relatively uniform sands that are loose to medium density. In addition to necessary soil conditions, the ground acceleration and duration of the earthquake must be of sufficient energy to induce liquefaction.

Liquefaction during major earthquakes has caused severe damage to structures on level ground as a result of settling, titling, or floating. Such damage occurred in San Francisco on bay-filled areas during the 1989 Loma Prieta earthquake, even though the epicenter was several miles away. If liquefaction occurs in or under a sloping soil mass, the entire mass may flow toward a lower elevation. Also of particular concern in terms of developed and newly developing areas are fill areas that have been poorly compacted.

The poorly consolidated younger alluvium that occupies valley floor areas of the county near Clear Lake basin are considered to have high to very high potential for liquefaction.

Settlement

Settlement can occur in poorly consolidated soils during ground shaking. During settlement, the soil materials are physically rearranged by the shaking to result in a less stable alignment of the individual minerals. Settlement of sufficient magnitude to cause significant structural damage is normally associated with rapidly deposited alluvial soils or improperly founded or poorly compacted fill. These areas are known to undergo extensive settling with the addition of irrigation water, but evidence due to ground shaking is not available.

Other Hazards

Earthquakes can also cause landslides and dam failures. Earthquakes may cause landslides (discussed in Section 4.2.13), particularly during the wet season, in areas of high water or saturated soils. Finally, earthquakes can cause dams to fail (see Section 4.2.6 Dam Failure). In addition, a large earthquake may cause a seiche in Clear Lake. A seiche is a tsunami on a lake that occurs as a result of earth shaking, often combined with landslide or other earth movements.

Geysers Geothermal Steam Field

The Geysers Geothermal Field is located west of the Middletown area in both Lake and Sonoma Counties (see Figure 4-25). Since the early 1980’s, geothermal power development has occurred in this area as a major industry. Seismic studies of the area have indicated there is a potential increase in micro seismic of 4.0 or less on the Richter scale with a relationship between micro seismic activity and geothermal production in the Geysers. A 4.0 or less earthquake does not result in dangerous ground shaking.

Lake County Public Review Draft 4-70 Local Hazard Mitigation Plan Update January 2018 Figure 4-25 Lake County – Geothermal Resource Areas

Source: 2008 Lake County General Plan Lake County Public Review Draft 4-71 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no disaster declarations in the County.

NCDC Events

Earthquake events are not tracked by the NCDC database.

USGS Events

The USGS National Earthquake Information Center database contains data on earthquakes in the Lake County area. Table 4-25 shows the approximate distances earthquakes can be felt away from the epicenter. According to the table, a magnitude 5.0 earthquake could be felt up to 90 miles away. The USGS database was searched for magnitude 5.0 or greater on the Richter Scale within 90 miles of the City of Clear Lake in Lake County. These results are detailed in Table 4-26.

Table 4-25 Approximate Relationships between Earthquake Magnitude and Intensity

Richter Scale Magnitude Maximum Expected Intensity (MM)* Distance Felt (miles) 2.0 - 2.9 I – II 0 3.0 - 3.9 II – III 10 4.0 - 4.9 IV – V 50 5.0 - 5.9 VI – VII 90 6.0 - 6.9 VII – VIII 135 7.0 - 7.9 IX – X 240 8.0 - 8.9 XI – XII 365 *Modified Mercalli Intensity Scale. Source: United State Geologic Survey, Earthquake Intensity Zonation and Quaternary Deposits, Miscellaneous Field Studies Map 9093, 1977.

Table 4-26 Magnitude 5.0 Earthquakes within 90 Miles of Lake County*

Date Richter Magnitude Location 12/14/2016 5.01 8km NW of The Geysers, California 8/10/2016 5.09 20km NNE of Upper Lake, California 8/24/2014 6.02 6km NW of American Canyon, California 9/3/2000 5 Northern California 1/24/1980 5.8 San Francisco Bay area, California 11/22/1977 5.2 Northern California 8/2/1975 5.2 Northern California 8/1/1975 5.7 0km WSW of Palermo, California Source: USGS *Search dates 1950 – July 1, 2017

Lake County Public Review Draft 4-72 Local Hazard Mitigation Plan Update January 2018 Figure 4-26 shows major historical earthquakes in California from 1769 to 2010.

Figure 4-26 Historic Earthquakes in California

Source: 2013 State of California Multi-Hazard Mitigation Plan

Lake County Public Review Draft 4-73 Local Hazard Mitigation Plan Update January 2018 Hazard Mitigation Planning Committee Events

Seismic activity within the past 200 years has shown absence of any major damaging earthquake occurring along the identified fault lines within Lake County. The HMPC has identified several earthquakes that were felt by area residents and/or caused damaging shaking in Lake County by faults outside the County. Details on some of these events follow.

➢ There was an earthquake in 1808 along the Healdsburg/Rogers fault. There is little known about the damages in the Lake County area from this event. ➢ On April 18, 1906 following the San Francisco 8.0 + earthquake on the San Andreas, widespread damage and loss of life affected several Northern California counties including Lake County. ➢ The 1989 Loma Prieta earthquake had minor impacts in Lake County. ➢ As previously mentioned, there are daily small earthquakes in the Geysers geothermal field west of Middletown. ➢ DETAILS OF EVENTS – ESPECIALLY THE 2014 and 2016 EVENTS FROM THE TABLE ABOVE

The HMPC also noted that recharge steam fields that causes small earthquakes. Two earthquakes not related to the geysers that are in the northeast portion in the County in the 4.0 range. Based on the fault lines that run in the County are on the eastern side and are a risk, with the Indian Valley Dam and the slide on Cache Creek with a bad winter that would add issues to the area. Propane tanks and mobile homes would be damaged.

Likelihood of Future Occurrence

Occasional (major earthquake); Highly Likely (minor earthquake)—Lake County seismic activity within the past two hundred years has shown absence of any major or damaging earthquake occurring on identified fault lines within Lake County. However, the possibility of an earthquake is an ever-present phenomenon in Lake County. The combination of plate tectonics and associated California coastal mountain range building geology, essentially guarantees earthquake as a result of the periodic release of tectonic stresses. Lake County’s mountainous terrain lies in the center of the North American and Pacific tectonic plate activity. There have been earthquakes as a result of this activity in the historic past, and there will continue to be earthquakes in the future of the California north coastal mountain region.

Mapping of Future Occurrences

Maps indicating the maximum expectable intensity of groundshaking for the County are available through several sources. Figure 4-27, prepared by the California Division of Mines and Geology, shows the expected relative intensity of ground shaking and damage in California from anticipated future earthquakes. The shaking potential is calculated as the level of ground motion that has a 2% chance of being exceeded in 50 years, which is the same as the level of ground-shaking with about a 2,500-year average repeat time. Although the greatest hazard is in areas of highest intensity as shown on the map, no region is immune from potential earthquake damage.

Lake County Public Review Draft 4-74 Local Hazard Mitigation Plan Update January 2018 Figure 4-27 Maximum Expectable Earthquake Intensity

Source: California Division of Mines and Geology

The U.S. Geological Survey (USGS) issues National Seismic Hazard Maps as reports every few years. These maps provide various acceleration and probabilities for time periods. Figure 4-28 depicts the peak horizontal acceleration (%g) with 10% probability of exceedance in 50 years (a 500-year event) for the planning region. The figure demonstrates that the County falls in the 40%g (orange) to 80%g (red). This data indicates that the expected severity of earthquakes in the region is relatively high, as damage from earthquakes typically occurs at peak accelerations of 30%g or greater.

Lake County Public Review Draft 4-75 Local Hazard Mitigation Plan Update January 2018 Figure 4-28 Peak Horizontal Acceleration with 10% Probability of Occurrence in 50 Years

Source: USGS National Seismic Hazard Maps

Figure 4-29 depicts the peak horizontal acceleration (%g) with 2% probability of exceedance in 50 years (a 2,500-year event) for the County. The figure demonstrates that the County falls in the 40%g (orange) to 80%g (red). This data indicates that the expected severity of earthquakes in the region is relatively high, as damage from earthquakes typically occurs at peak accelerations of 30%g or greater.

Lake County Public Review Draft 4-76 Local Hazard Mitigation Plan Update January 2018 Figure 4-29 Peak Horizontal Acceleration with 2% Probability of Occurrence in 50 Years

Source: USGS National Seismic Hazard Maps

In 2014, the USGS and the California Geological Survey (CGS) released the time‐dependent version of the Uniform California Earthquake Rupture Forecast (UCERF III) model. The UCERF III results have helped to reduce the uncertainty in estimated 30‐year probabilities of strong ground motions in California. The UCERF map is shown in Figure 4-30 and indicates that Lake County has a moderate to high risk of earthquake occurrence, which coincides with the likelihood of future occurrence rating of occasional.

Lake County Public Review Draft 4-77 Local Hazard Mitigation Plan Update January 2018 Figure 4-30 Probability of Earthquake Magnitudes Occurring in 30 Year Time Frame

Source: United States Geological Survey Open File Report 2015‐3009

Climate Change and Earthquake

Climate changes is unlikely to increase earthquake frequency or strength.

4.2.12. Flood: 1%/0.2% Annual Chance

Hazard/Problem Description

Flooding is the rising and overflowing of a body of water onto normally dry land. History clearly highlights floods as one of the natural hazards impacting Lake County. Floods are among the most costly natural disasters in terms of human hardship and economic loss nationwide. Floods can cause substantial damage to structures, landscapes, and utilities as well as life safety issues. Floods can be extremely dangerous, and even six inches of moving water can knock over a person given a strong current. A car will float in less than two feet of moving water and can be swept downstream into deeper waters. This is one reason floods kill more people trapped in vehicles than anywhere else. During a flood, people can also suffer heart attacks or electrocution due to electrical equipment short outs. Floodwaters can transport large objects downstream

Lake County Public Review Draft 4-78 Local Hazard Mitigation Plan Update January 2018 which can damage or remove stationary structures, such as dam spillways. Ground saturation can result in instability, collapse, or other damage. Objects can also be buried or destroyed through sediment deposition. Floodwaters can also break utility lines and interrupt services. Standing water can cause damage to crops, roads, foundations, and electrical circuits. Direct impacts, such as drowning, can be limited with adequate warning and public education about what to do during floods. Where flooding occurs in populated areas, warning and evacuation will be of critical importance to reduce life and safety impacts from any type of flooding.

Health Hazards from Flooding

Certain health hazards are also common to flood events. While such problems are often not reported, three general types of health hazards accompany floods. The first comes from the water itself. Floodwaters carry anything that was on the ground that the upstream runoff picked up, including dirt, oil, animal waste, and lawn, farm and industrial chemicals. Pastures and areas where cattle and hogs are kept or their wastes are stored can contribute polluted waters to the receiving streams.

Floodwaters also saturate the ground, which leads to infiltration into sanitary sewer lines. When wastewater treatment plants are flooded, there is nowhere for the sewage to flow. Infiltration and lack of treatment can lead to overloaded sewer lines that can back up into low-lying areas and homes. Even when it is diluted by flood waters, raw sewage can be a breeding ground for bacteria such as e. coli and other disease causing agents.

The second type of health problem arises after most of the water has gone. Stagnant pools can become breeding grounds for mosquitoes, and wet areas of a building that have not been properly cleaned breed mold and mildew. A building that is not thoroughly cleaned becomes a health hazard, especially for small children and the elderly.

Another health hazard occurs when heating ducts in a forced air system are not properly cleaned after inundation. When the furnace or air conditioner is turned on, the sediments left in the ducts are circulated throughout the building and breathed in by the occupants. If a city or county water system loses pressure, a boil order may be issued to protect people and animals from contaminated water.

The third problem is the long-term psychological impact of having been through a flood and seeing one’s home damaged and irreplaceable keepsakes destroyed. The cost and labor needed to repair a flood-damaged home puts a severe strain on people, especially the unprepared and uninsured. There is also a long-term problem for those who know that their homes can be flooded again. The resulting stress on floodplain residents takes its toll in the form of aggravated physical and mental health problems.

Warning and Evacuation Procedures

Lake County and its incorporated communities have a variety of systems and procedures established to protect its residents and visitors to plan for, avoid, and respond to a hazard event including those associated with floods and wildfires. This includes Pre-Disaster Public Awareness and Education information which is major component in successfully reducing loss of life and property in a community when faced with a potentially catastrophic incident. Much of this information is not specific to a given hazard event and is

Lake County Public Review Draft 4-79 Local Hazard Mitigation Plan Update January 2018 always accessible to the public on local County and City websites. Specific warning and evacuation systems and procedures include information relative to: CodeRed Emergency Mass Notification System which can send out telephone, email, and text alerts to registered phones. The County is updating its evacuation language to mirror evacuation language use in the FireScope FOG Manual. Additional information on these warning and evacuation procedures as well as post-disaster mitigation policies and procedures can be found in Section 4.4, Capabilities, of this Risk Assessment. UPDATE THIS LANGUAGE. IT IS EXAMPLE LANGUAGE FROM OTHER PLANS.

Floodplains

The area adjacent to a channel is the floodplain (see Figure 4-31). Floodplains are illustrated on inundation maps, which show areas of potential flooding and water depths. In its common usage, the floodplain most often refers to that area that is inundated by the 1% annual chance (or 100-year) flood, the flood that has a one percent chance in any given year of being equaled or exceeded. The 1% annual chance flood is the national minimum standard to which communities regulate their floodplains through the National Flood Insurance Program. The 500-year flood is the flood that has a 0.2% chance of being equaled or exceeded in any given year. The potential for flooding can change and increase through various land use changes and changes to land surface, which result in a change to the floodplain. A change in environment can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity.

Figure 4-31 Floodplain Schematic

Source: FEMA

Lake County Public Review Draft 4-80 Local Hazard Mitigation Plan Update January 2018 The Lake County Planning Area is susceptible to various types of flood events as described below.

➢ Riverine flooding – Riverine flooding, defined as when a watercourse exceeds its “bank-full” capacity, generally occurs as a result of prolonged rainfall, or rainfall that is combined with already saturated soils from previous rain events. This type of flood occurs in river systems whose tributaries may drain large geographic areas and include one or more independent river basins. The onset and duration of riverine floods may vary from a few hours to many days. Factors that directly affect the amount of flood runoff include precipitation amount, intensity and distribution, the amount of soil moisture, seasonal variation in vegetation, snow depth, and water-resistance of the surface due to urbanization. In the Lake County Planning Area, riverine flooding is largely caused by heavy and continued rains, sometimes (though rarely) combined with snowmelt, and heavy flow from tributary streams. These intense storms can overwhelm the local waterways as well as the integrity of flood control structures. The warning time associated with slow rise floods assists in life and property protection. ➢ Flash flooding – Flash flooding describes localized floods of great volume and short duration. This type of flood usually results from a heavy rainfall on a relatively small drainage area. Precipitation of this sort usually occurs in the winter and spring. Flash floods often require immediate evacuation within the hour and thus early threat identification and warning is critical for saving lives ➢ Localized/Stormwater flooding – Localized flooding problems are often caused by flash flooding, severe weather, or an unusual amount of rainfall. Flooding from these intense weather events usually occurs in areas experiencing an increase in runoff from impervious surfaces associated with development and urbanization as well as inadequate storm drainage systems. More on localized flooding can be found in Section 4.2.13. ➢ Dam failure flooding – Flooding from failure of one or more upstream dams is also a concern to the Lake County Planning Area. A catastrophic dam failure could easily overwhelm local response capabilities and require mass evacuations to save lives. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Major loss of life could result, and there could be associated health concerns as well as problems with the identification and burial of the deceased. Dam failure is further addressed in Section 4.2.6 Dam Failure.

Major Sources of Flooding

California has 10 hydrologic regions. Lake County sits in the Sacramento and North Coast hydrologic regions.

➢ The Sacramento River hydrologic region covers approximately 17.4 million acres (27,200 square miles). The region includes all or large portions of Modoc, Siskiyou, Lassen, Shasta, Tehama, Glenn, Plumas, Butte, Colusa, Sutter, Yuba, Sierra, Nevada, Placer, Sacramento, El Dorado, Yolo, Solano, Lake, and Napa counties. Small areas of Alpine and Amador counties are also within the region. Geographically, the region extends south from the Modoc Plateau and Cascade Range at the Oregon border, to the Sacramento-San Joaquin Delta. The Sacramento Valley, which forms the core of the region, is bounded to the east by the crest of the Sierra Nevada and southern Cascades and to the west by the crest of the Coast Range and Klamath Mountains. The Sacramento metropolitan area and surrounding communities form the major population center of the region. With the exception of Redding, cities and towns to the north, while steadily increasing in size, are more rural than urban in nature, being based in major agricultural areas.

Lake County Public Review Draft 4-81 Local Hazard Mitigation Plan Update January 2018 ➢ The North Coast Hydrologic Region encompasses redwood forests, inland mountain valleys, and the semi-desert-like Modoc Plateau. The region includes all or large parts of Modoc, Siskiyou, Del Norte, Trinity, Humboldt, Mendocino, Lake, and Sonoma counties. It also includes small areas of Glenn and Marin counties. The region includes the Pacific Ocean coastline from Tomales Bay to Oregon, and then extends east along the border to the Goose Lake Basin. This region covers roughly 19,500 square miles, or more than 12 percent of California’s land area. Most of the region is mountainous and rugged. The dominant topographic features in the region are the California Coast Range, the Klamath Mountains, and Modoc Plateau. The mountain crests, which form the eastern boundary of the region, are about 6,000 feet elevation with a few peaks higher than 8,000 feet. About 425 miles of ocean shoreline form the western boundary of the region. All streams in the North Coast Hydrologic Region empty into the Pacific Ocean between Bodega Bay and Oregon. Only 13 percent of the land is classified as valley or mesa, and more than half of that is in the higher-elevation northeastern part of the region in the upper Klamath River Basin.

A map of the California’s hydrological regions is provided in Figure 4-32.

Lake County Public Review Draft 4-82 Local Hazard Mitigation Plan Update January 2018 Figure 4-32 California Hydrologic Regions

Source: California Department of Water Resources

Lake County Public Review Draft 4-83 Local Hazard Mitigation Plan Update January 2018 The Lake County Waterway System

The 2014 Preliminary FIS noted that Lake County is characterized by diversified topography. Its southern portion is typical California foothill country, with rolling hills and level valleys; the central portion is dominated by the Clear Lake depression; and its northern sector is mostly rugged mountains. Elevations range from approximately 600 feet, where Putah Creek crosses the southeastern county boundary, to over 7,000 feet at Snow Mountain on the eastern boundary. Much of the terrain in headwater areas, especially in the northern sector, is quite precipitous. Drainage from the northern part of Lake County is westward, directly to the ocean, and drainage in the central and southern sectors is eastward to Clear Lake, which eventually ends up in the Sacramento River. Lake County encompasses multiple rivers, streams, creeks, and associated watersheds. Lake County crosses 6 watersheds. These include the following watersheds:

➢ Upper Eel Watershed ➢ Middle Fork Eel Watershed ➢ Russian Watershed ➢ Upper Stony Watershed ➢ Upper Cache Watershed ➢ Upper Putah Watershed

Lake County contains an abundance of streams and lakes. Cole Creek, Adobe Creek, Anderson Creek, Copsey Creek, Coyote Creek, Dry Creek, Herndon Creek, Kelsey Creek, North Fork Cache Creek, Puta Creek, Schindler Creek, Scotts Creek, and St. Helena Creek all run through areas of the County. Clear Lake, Pillsbury, and Indian Valley Reservoir are the principal bodies of water in Lake County:

➢ Clear Lake, the largest freshwater lake entirely in California, covers an area of 64 square miles at a normal lake level of 1,320 feet. Its principal tributaries are Scotts, Middle, Clover, Kelsey, and Adobe Creeks. The creeks enter the north end of the lake by way of Rodman Slough, Kelsey, and Adobe Creeks. Outflow from the lake is controlled by a small dam on Cache Creek. Active storage capacity is defined by a court decree that sets upper and lower stages. Within these decree limits, storage capacity is approximately 315,000 acre-feet. ➢ Lake Pillsbury, a power and irrigation project in the Eel River drainage, is situated in the northwest corner of the county. The reservoir has a surface area of approximately 3 square miles, a lake level of approximately 1,800 feet, and a storage capacity of 87,000 acre-feet. ➢ Indian Valley Reservoir is a multiple purpose project located 11 miles upstream from the mouth of North Fork Cache Creek. It has a surface area of approximately 6 square miles, a storage capacity of 300,000 acre-feet, and a gross pool elevation of 1,485 feet.

Other smaller bodies of water in Lake County are Upper and Lower Blue Lakes, Thurston Lake, Borax Lake, Little Borax Lake, and Highland Lake. Some of the lakes at the higher elevations are intermittent.

Figure 4-33 illustrates the primary watersheds of Lake County, as well as the primary waterways in the County.

Lake County Public Review Draft 4-84 Local Hazard Mitigation Plan Update January 2018 Figure 4-33 Primary Watersheds and Waterways of Lake County

Lake County Public Review Draft 4-85 Local Hazard Mitigation Plan Update January 2018 The Water Resources element of the 2008 Lake County General Plan also discussed water resources in the County. The primary purpose of the Water Resources Element is to ensure that Lake County’s surface and groundwater resources are protected and sustained. This element contains goals, policies, and programs designed to address water resources. It also contains a map of water resources in the County. This can be seen in Figure 4-34.

Lake County Public Review Draft 4-86 Local Hazard Mitigation Plan Update January 2018 Figure 4-34 Lake County – Water Resources

Source: 2008 Lake County General Plan

Lake County Public Review Draft 4-87 Local Hazard Mitigation Plan Update January 2018 Flooding in Lake County

The 2014 Preliminary FIS noted that flooding in Lake County results from prolonged heavy rainfall over tributary areas during the period from November through March. Flooding is more severe either when antecedent rainfall has caused saturated ground conditions or when the ground is frozen in the higher elevations and infiltration is minimal. On rare occasions, melting snow could augment runoff from general rain. Rain flooding on streams is characterized by high peak flows with durations of 2 to 3 days. On Clear Lake, stage could continue above flood level for many days. In the northern sector of the County, floods in the Eel River drainage would be extremely rare events and, due to the lack of development, damage potential is minimal. The outlets of Lake Pillsbury are normally open during the winter and closed during spring to store for power and irrigation. The channel downstream is capable of containing all high flows that could reasonably be expected.

Of the streams, tributaries to Clear Lake, Scotts, Cole, Kelsey, and Adobe Creeks have the most serious flooding problems. These streams also contribute significantly to high lake stages and lakeshore flooding. Windset may increase the depth and extent of shoreline flooding, but the most important factor is inadequate outlet capacity, which increases and prolongs high lake stages. Clear Lake Dam is capable of impounding water in the lake to an elevation of 10.3 feet on the Rumsey gage (located on the city wharf in Lakeport) or approximately 1,329 feet above the National Geodetic Vertical Datum 1929 (NGVD). The gage datum is 1318.26, and lake stages are converted to elevations above NGVD by adding this figure.

Orders of the Superior Court of the State of California in and for the County of Mendocino set limits to raising the level of Clear Lake (Noted in the FIS as M.M Gopcevic et. al. versus Yolo Water and Power Company, a corporation et. al., October 7, 1920). These orders prohibit raising Clear Lake above 7.56 feet above zero on the Rumsey Gauge; the level may be raised above 7.56 feet but not above 9.00 feet for a period not exceeding ten successive days during storms. It is not physically possible to operate within these limits because outflow is restricted by the Grigsby Riffle, a natural restriction on the outlet channel upstream of the dam. In order to reduce flooding, efforts were made in 1938 to reduce the restriction at the Grigsby Riffle. However, the courts stopped these actions. The Superior Court of the State of California in and for the County of Yolo prohibited changing the outlet of Clear Lake to increase the flow of waters from Clear Lake into Cache Creek (Note in the FIS as Mary E. Bemmerly and Agnes H. Bemmerly versus the County of Lake et. al., December 18, 1940). In essence, the effect of the court orders is to prolong flood stages and prevent their rapid reduction. Flood conditions along the lakeshore may continue for as long as 90 days.

Flood problems along Cache Creek downstream from Clear Lake are largely confined to the main stem reach in the vicinity of Lower Lake and along the lower reaches of North Fork Cache Creek. In the Putah Creek basin, the principal flood problems are in Coyote and Collayami Valleys and in Middletown.

Other Sources of Flooding

A weather pattern called the “Pineapple Express”, which is also known as an atmospheric river, contributes to the flooding potential of the area. A pineapple express brings warm air and rain to the West Coast. A relatively common weather pattern brings southwest winds to the Pacific Northwest or California, along with warm, moist air. The moisture sometimes produces many days of heavy rain, which can cause extensive flooding. The warm air also can melt the snow pack in the mountains, which further aggravates

Lake County Public Review Draft 4-88 Local Hazard Mitigation Plan Update January 2018 the flooding potential. In the colder parts of the year, the warm air can be cooled enough to produce heavy, upslope snow as it rises into the higher elevations of the Sierra Nevada or Cascades. Forecasters and others on the West Coast often refer to this warm, moist air as the “Pineapple Express” because it comes from around Hawaii where pineapples are grown. This is shown in Figure 4-35.

Figure 4-35 Pineapple Express Weather Pattern

Source: USA TODAY research by Chad Palmer http://www.usatoday.com/weatherwpinappl.htm

Lake County Flood Mapping

As part of the County’s ongoing efforts to identify and manage their flood prone areas, Lake County relies on a variety of different mapping efforts. What follows is a brief description of FEMA and DWR mapping efforts covering the Lake County Planning Area.

FEMA Floodplain Mapping

FEMA established standards for floodplain mapping studies as part of the National Flood Insurance Program (NFIP). The NFIP makes flood insurance available to property owners in participating communities adopting FEMA-approved local floodplain studies, maps, and regulations. Floodplain studies that may be approved by FEMA include federally funded studies; studies developed by state, city, and regional public agencies; and technical studies generated by private interests as part of property annexation and land development efforts. Such studies may include entire stream reaches or limited stream sections depending on the nature and scope of a study. A general overview of floodplain mapping is provided in the

Lake County Public Review Draft 4-89 Local Hazard Mitigation Plan Update January 2018 following paragraphs. Details on the NFIP and mapping specific to the County are in Section 4.3 Vulnerability Assessment.

Flood Insurance Study (FIS)

The FIS develops flood-risk data for various areas of the community that will be used to establish flood insurance rates and to assist the community in its efforts to promote sound floodplain management. The current Lake County FIS is dated September 30, 2005. This study covers both the unincorporated and incorporated areas of the County. The FIS is in the process of being updated. A preliminary FIS, dated June 18, 2014 was issued and was used during the development of this Plan Update.

Flood Insurance Rate Map (FIRM)

The FIRM is designed for flood insurance and floodplain management applications. For flood insurance, the FIRM designates flood insurance rate zones to assign premium rates for flood insurance policies. For floodplain management, the FIRM delineates 1% and 0.2% annual chancer floodplains, floodways, and the locations of selected cross sections used in the hydraulic analysis and local floodplain regulation. The County FIRMs have been replaced by digital flood insurance rate maps (DFIRMs) as part of FEMA’s Map Modernization program, which is discussed further below.

Letter of Map Revision (LOMR) and Map Amendment (LOMA)

LOMRs and LOMAs represent separate floodplain studies dealing with individual properties or limited stream segments that update the FIS and FIRM data between periodic FEMA publications of the FIS and FIRM.

Digital Flood Insurance Rate Maps (DFIRM)

As part of its Map Modernization program, FEMA is converting paper FIRMS to digital FIRMs, DFIRMS. These digital maps:

➢ Incorporate the latest updates (LOMRs and LOMAs); ➢ Utilize community supplied data; ➢ Verify the currency of the floodplains and refit them to community supplied basemaps; ➢ Upgrade the FIRMs to a GIS database format to set the stage for future updates and to enable support for GIS analyses and other digital applications; and ➢ Solicit community participation.

DFIRMs for Lake County have been developed, are dated September 30, 2005, and are being used for the flood analysis for this LHMP Update. A new DFIRM update is in process. A preliminary FIS and DFIRM, dated June 18, 2014 were released. This DFIRM data has not been finalized, and was not used for analysis is this Plan Update. Information from the preliminary 2014 FIS was used.

CAN WE GET ANY INFO ON WHAT WAS CHANGED FROM 2005 to 2014 MAPS?

Lake County Public Review Draft 4-90 Local Hazard Mitigation Plan Update January 2018 California Department of Water Resources Best Available Maps (BAM)

Also to be considered when evaluating the flood risks in Lake County are various floodplain maps developed by the California DWR for various areas throughout California, and in the Sacramento-San Joaquin Valley cities and counties. The FEMA regulatory maps provide just one perspective on flood risks in Lake County. Senate Bill 5 (SB 5), enacted in 2007, authorized the California DWR to develop the Best Available Maps (BAM) displaying 1% and 0.5% (200-year) annual chance floodplains for areas located within the Sacramento-San Joaquin (SAC-SJ) Valley watershed. This effort was completed by DWR in 2008. DWR has expanded the BAM to cover all counties in the State and to include 0.2% annual chance floodplains.

Different than the FEMA DFIRMs which have been prepared to support the NFIP and generally reflect only the 1% and 0.2% annual chance flood risks, the BAMs are provided for informational purposes and are intended to reflect current 1%, 0.5% (200-year) as applicable, and 0.2% annual chance flood risks using the best available data. The 100-year floodplain limits on the BAM are a composite of multiple 1% annual chance floodplain mapping sources. It is intended to show all currently identified areas at risk for a 100- year flood event, including FEMA’s 1% annual chance floodplains. The BAM are comprised of different engineering studies performed by FEMA, Corps, and DWR for assessment of potential 1%, 0.5%, and 0.2% annual chance floodplain areas. These studies are used for different planning and/or regulatory applications, and for each flood frequency may use varied analytical and quality control criteria depending on the study type requirements.

The value in the BAMs is that they provide a bigger picture view of potential flood risk to the County than that provided in the FEMA DFIRMs. This provides the community and residents with an additional tool for understanding potential flood hazards not currently mapped as a regulated floodplain. Improved awareness of flood risk can reduce exposure to flooding for new structures and promote increased protection for existing development. Informed land use planning will also assist in identifying levee maintenance needs and levels of protection. By including the FEMA 1% annual chance floodplain, it also supports identification of the need and requirement for flood insurance. Figure 4-36 shows the BAM for the Lake County Planning Area.

Lake County Public Review Draft 4-91 Local Hazard Mitigation Plan Update January 2018 Figure 4-36 Lake County– Flood Awareness (Best Available) Map

Source: California DWR Legend explanation: Blue - FEMA 1%, Orange – Local 1% (developed from local agencies), Red – DWR 1%r (Awareness floodplains identify the 1% annual chance flood hazard areas using approximate assessment procedures.), Pink – USACE 1% (2002 Sac and San Joaquin River Basins Comp Study), Yellow – USACE 0.5% (2002 Sac and San Joaquin River Basins Comp Study), Tan – FEMA 0.2%, Grey – Local 0.2% (developed from local agencies), Purple – USACE 0.2%(2002 Sac and San Joaquin River Basins Comp Study).

Lake County Public Review Draft 4-92 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

A list of state and federal disaster declarations for Lake County from flooding is shown on Table 4-27.

Table 4-27 Lake County – State and Federal Disaster Declaration from Flood 1950-2017

NCDC Events

The NCDC tracks flooding events for the County. Events have been tracked for flooding since 1993. Table 4-28 shows events in Lake County since 1993. Information on specific events from this table that affected Lake County are described below the table.

Table 4-28 NCDC Flood Events in Lake County 1993 to 3/31/2017

Deaths Injuries Property Crop Injuries Deaths Date Event (direct) (direct) Damage Damage (indirect) (indirect) 1/25/1997 Flash Flood 0 0 $0 $0 0 0 1/1/1997 Flood 0 0 $0 $0 0 0 1/1/1997 Flood 0 0 $0 $0 0 0 2/2/1998 Flood 0 0 $0 $0 0 0 2/2/1998 Flood 0 0 $15,000,000 $0 0 0 2/2/1998 Flood 0 0 $0 $0 0 0 2/11/2000 Flood 0 0 $0 $0 0 0 1/1/2006 Flood 1 1 $1,000,000 $0 0 0 12/11/2014 Flood 0 0 $400,000 $0 0 0 1/10/2017 Flood 0 0 $10,000 $0 0 0 2/9/2017 Flood 0 0 $7,000,000 $0 0 0 Totals 1 1 $23,410,000 $0 0 0 Source: NCDC

➢ February 2nd to 28th, 1998 – The Clear Lake region of Lake County was hit hard by flooding. Clear Lake is a very slow--draining natural lake (on a day with no rainfall, the lake drains at about the rate of 1 inch per 24 hours when at these reported levels). 500 residents in the town of Clearlake Oaks were evacuated and kept from their homes for weeks. This town alone suffered $5 million of the damage

Lake County Public Review Draft 4-93 Local Hazard Mitigation Plan Update January 2018 recorded above. The town of Lakeport had 60 homes flooded. Rainfall rates of 4 inches in 6 hours were observed during the 2nd and 3rd. Clear Lake reached all-time record levels on the 23rd, 2.5 feet above flood stage. The flooding continued into March and April. The main transportation artery through the county, State Route 20, was closed for weeks. In total, $15 million in damages were recorded, though most of the damages were not in Lake County. No deaths or injuries were reported. ➢ January 1st to 3rd, 2006 – A series of warm winter storms brought heavy rain, mudslides, flooding, and high winds to Northern California. Three deaths occurred due to these storms. A Solano County man was killed by a falling tree, a Lake County man drowned while fishing during the storm, and a Stanislaus County woman died while crossing a flooding stream on foot. Counties declared in need of federal disaster assistance include: Alpine, Amador, Butte, Colusa, El Dorado, Lake, Nevada, Placer, Plumas, Sacramento, San Joaquin, Shasta, Solano, Sutter, Yolo, and Yuba. In total, $1 million in damages were recorded, though most of the damages were not in Lake County. ➢ December 11, 2014 – An atmospheric river event beginning early December 11th brought periods of heavy rainfall, flooding from overly saturated grounds and high river/stream water levels, and heavy snow above 7000 ft. Windy conditions persisted through the event, causing trees and tree branches to fall down and localized power outages affecting hundreds of thousands of homes across Northern California. Snowfall of 1 to 2 feet caused travel problems at Sierra passes. Winds were reported to reach as high as 50-60 mph in the valley/foothill region, and over 100 mph in the mountains. On December 22, Governor Brown declared a state of emergency for heavy rain, flooding and wind damage in counties including Tehama, Lake, Shasta, and Yolo. Flooding was reported in Clearlake, bringing significant and widespread damage. Neighborhoods were evacuated. Roads were damaged. Extensive road repair and debris removal was required. No deaths or injuries were reported. ➢ February 2, 2017 – Storms brought a range of significant weather impacts to northern interior California. The first storm was very wet and warm, the second not quite as wet but cooler with lower snow levels. Both storms brought strong, damaging winds. The heavy rain brought widespread flooding of small streams and rivers, with some flooding of main stem rivers. Wet conditions from previous storms brought saturated ground and elevated reservoirs, with flood control releases. There was also mountain snow many feet deep, and damaging winds, with numerous trees down on roads, vehicles, and homes. Many roads, including major highways such as Interstate 80, were shut down due to mudslides, heavy snow, flooding, washouts or avalanche suppression. Other significant impacts include numerous accidents due to slippery roads, evacuations and rescues due to flooding. Event Narrative Flooding of Clear Lake brought the closure of multiple roads. Lakeshore Boulevard was closed due to flooding between Lange Street and Giselman Street, Other strees closed included Esplanade Street, K Street, Konoctie Avenue, and Lupoyoma Avenue. Clear Lake’s level stayed in flood stage for a month and led to mandatory evacuations in parts of the city of Lakeport. Lake County Public Works Director said early assessments suggested damage to county-maintained roads ranged between $5 million and $7 million. No deaths or injuries were reported in Lake County.

FIS Events

Clear Lake, its tributaries, and other streams in Lake County have a long history of flooding. Several flood periods are documented during the last half of the 20th century, and many severe floods have occurred since 1900. Stage recordings for Clear Lake have been maintained since 1874. These records show that a 7.56- foot stage on the Rumsey Gage has been exceeded 54 times and a 9-foot stage on the Rumsey Gage has been exceeded 27 times. Some of the most damaging floods of recent times have occurred in 1937-38, 1940, 1956, 1958, 1964-65, 1970, 1974, 1983, and 1986. The maximum known stage on Clear Lake, 13.66

Lake County Public Review Draft 4-94 Local Hazard Mitigation Plan Update January 2018 feet, occurred in January 1890. The next highest stage, 13.38 feet, occurred in February 1909. Some of the higher lake stages that have occurred since construction of Clear Lake Dam in 1915 are shown in Table 4-29.

Table 4-29 Flood Stages for Clear Lake since 1915

Date Stage (feet) Elevation (feet NGVD)* February 1938 10.25 1,328.84 February 1942 9.60 1,328.19 February 1956 9.53 1,328.18 February 1958 10.86 1,329.51 January 1965 9.03 1,327.68 January 1970 10.37 1,329.02 April 1974 9.10 1,327.75 February 1980 9.61 1,328.26 April 1982 9.17 1,327.82 March 1983 11.32 1,329.58 February 1986 11.34 1,329.60 March 1995 10.73 1,328.99 February 1998 11.44 1,329.70 Source: 2014 Preliminary FIS *The elevation figure represents a combination of lake stage and appropriate gage elevation datum; gage datum (feet NGVD): 1,318.59 feet through 1947; 1,318.65 feet 1947 through 1982; 1,318.26 feet to present (U.S. Department of the Interior, Water Resources Data, Gage No. 11450000).

In 1958, the lake level exceeded decree level (7.56 feet) on February 4, was 10.2 feet at the time of peak tributary inflow on February 24, and reached its maximum in 50 years (10.88 feet) on February 27. After slowly receding to 8.0 feet on March 20, the lake again rose to 10.0 feet on April 6 and did not recede to decree level until early June. The maximum possible release from the lake happened during the entire period.

In addition to the clouding of Clear Lake, the FIS noted the following events:

In the last 50 years, Lakeport has experienced six stream bank overflow flood events. The flooding occurred in December 1937, February 1940, December 1964, January 1970, January 1983, and February 1986.

A downpour in mid-December 1937 caused Forbes Creek to overflow its banks and flood easterly along Martin Street for several blocks and then northerly along Main Street. Flooding also occurred along Tenth Street from Tenth Street Drain overflow. Residential, commercial, and agricultural properties were flooded and damaged. Substantial streambank erosion was caused and roads throughout the area were closed due to inundation by floodwaters and the deposition of debris.

Lake County Public Review Draft 4-95 Local Hazard Mitigation Plan Update January 2018 The February 1940 floodwaters inundated property at several locations in Lakeport, especially along Martin Street from Forbes Creek to Main Street and along Tenth Street. The floodwaters inundated agricultural, residential, and commercial properties, and overflowed roads causing short-term closures.

During the December 1964 cloudburst, flooding on Martin Street looked like a full-fledged river. Main Street was flooded and some businesses were inundated. Others were sandbagged to prevent flooding. City crews worked many hours pumping water and sandbagging. Numerous streets were closed by floodwaters, and south of the city, much of State Highway 29 was covered by floodwaters and debris.

In January 1970, extensive rainfall caused flooding of 1- to 2-foot depths in lower, eastern parts of the city. Resort areas, trailer parks, and campgrounds were inundated, and traffic on some roads was diverted. Residential and commercial areas and public facilities suffered damages.

In January 1983, floodwaters forced the closure of streets and roads in various locations around town for indefinite periods of time. Several blocks of Martin and Armstrong Streets were closed as were Main Street at Tenth and Eleventh Streets and portions of major county and state highways northwest and south of the City. Flood fighting and sandbagging efforts took place on Martin and South Main Streets.

In February 1986, flooding affected practically all sections of Lakeport. In the northeastern section, city firefighters sandbagged in the Lakeshore Boulevard area and helped in evacuation work there. In the east- central section, floodwaters covered much of Tenth Street. In the west-central section, Compton and Spun Streets were flooded. In the southeastern section, portions of Martin and South Main Streets were impassable and along Esplanade, city firemen evacuated some residents. In the eastern section (the lakefront), water was in the front yards of lakeside homes and much sandbagging was done to prevent further damage. Sandbagging activities were accomplished throughout the city to protect residences and businesses. Sewer pumps in many areas were working 24 hours a day for an extended period to alleviate further problems.

Major floods in Lakeport, caused by cloudbursts and high lake stages, generally inundate residential and commercial properties and recreation/vacation facilities. Agricultural land is inundated causing erosion, damaged or destroyed crops, and loss of production. Streets, roads, and highways are either overtopped, washed out, or covered with debris causing the temporary cessation of traffic flow. Flood- fighting activities (such as sandbagging) are necessary, and the evacuation of flooded areas is sometimes required.

Hazard Mitigation Planning Committee Events

The HMPC provided additional information on the following historical flood events in the County.

➢ INSERT ANY EVENTS NOT CAPTURED ABOVE

Lake County Public Review Draft 4-96 Local Hazard Mitigation Plan Update January 2018 Likelihood of Future Occurrence

1% Annual Chance Flood

Occasional— The 1% annual chance flood (100-year) is the flood that has a 1 percent chance of being equaled or exceeded in any given year. This, by definition, makes the likelihood of future occurrence occasional. However, the 100-year flood could occur more than once in a relatively short period of time.

0.2% Annual Chance Flood

Unlikely—The 0.2% annual chance flood (500-year) is the flood that has a 0.2 percent chance of being equaled or exceeded in any given year. This, by definition, makes the likelihood of future occurrence unlikely.

Climate Change and Flood

According to the CAS, climate change may affect flooding in Lake County. While average annual rainfall may increase or decrease slightly, the intensity of individual rainfall events is likely to increase during the 21st century. It is possible that average soil moisture and runoff could decline, however, due to increasing temperature, evapotranspiration rates, and spacing between rainfall events. Reduced snowpack and increased number of intense rainfall events are likely to put additional pressure on water infrastructure which could increase the chance of flooding associated with breaches or failures of flood control structures such as levees and dams. Future precipitation projections were shown in Figure 4-10 in Section 4.2.3.

4.2.13. Flood: Localized Flooding

Hazard/Problem Description

Flooding occurs in areas other than the FEMA mapped floodplains. Flooding may be from drainages not studied by FEMA, lack of or inadequate drainage infrastructure, or inadequate maintenance. Most streams, drainage channels, and drainage facilities are not maintained by a public agency and are the responsibility of individual property owners, and occasionally non-governmental organizations.

Localized, stormwater flooding also occurs throughout the County during the rainy season from November through April. Prolonged heavy rainfall contributes to a large volume of runoff resulting in high peak flows of moderate duration. Flooding is more severe when previous rainfall has created saturated ground conditions. Urban storm drainpipes and pump stations have a finite capacity. When rainfall exceeds this capacity, or the system is clogged, water accumulates in the street until it reaches a level of overland release. This type of flooding may occur when intense storms occur over areas of development.

In addition to flooding, damage to these areas during heavy storms can include pavement deterioration, washouts, landslides/mudslides, debris areas, and downed trees. The amount and type of damage or flooding that occurs varies from year to year, depending on the quantity of runoff. These areas and the types of damage are presented in Table 4-30. PLEASE PROVIDE COMPLETED TABLE OF LOCALIZED FLOOD ISSUE/PROBLEM AREAS. HAVE ANY MAPS BEEN DEVELOPED OF PROBLEM AREAS – WHAT ABOUT FOR DAMAGES FROM THE MOST RECENT 2017 STORMS?

Lake County Public Review Draft 4-97 Local Hazard Mitigation Plan Update January 2018 Table 4-30 Lake County Localized Flooding Areas

High Water/ Pavement Creek Landslides/ Downed Road Name Flooding Deterioration Washouts Crossing Mudslides Debris Trees Esplanade St X X X X (Lakeport) Lakeshore X X X X X Boulevard (Lakeport) Royale Avenue X X X (Lakeport) Park Street X X X (Lakeport) Martin Street X X X (Lakeport)

Source: Lake County

WHAT AREAS ARE WORST? CAN WE GET SOME WRITE UPS ABOUT THESE AREAS?

Past Occurrences

Disaster Declarations

There are no identified state or federal disaster declarations for localized flooding. However, localized flooding was likely an issue during previous declarations for severe storms, heavy rains and floods.

NCDC Events

The past occurrences of localized flooding are included in the 1% and 0.2% annual chance flood hazard profile in Section 4.2.12.

Hazard Mitigation Planning Committee Events

The HMPC noted the following additional past occurrences of localized flooding:

➢ Flooding has historically been one of Lakeport’s major safety concerns. In the past thirty-five years, federal disasters due to flooding were declared nine times in the City of Lakeport during 1983, 1986,

Lake County Public Review Draft 4-98 Local Hazard Mitigation Plan Update January 2018 1995 (twice), 1997, 1998, 2006 and 2017 (twice). Flooding in Lakeport historically results from two distinct types of events: shoreline flooding due to high lake levels and wind velocity, and stream bank flooding caused by high intensity cloudburst storms over one or more of the drainage areas. Notable public streets affected by high lake levels include Esplanade Street, Lakeshore Boulevard, Royale Avenue and Park Street. Public streets affected by high intensity storms include Martin Street. The Lake County Sheriff’s Office is located on Martin Street near Lakeport’s western city limit boundary. ➢ PAST OCCURRENCES OF LOCALIZED FLOODS AND DETAILS NOT CAPTURED ABOVE? 2017 STORMS?

Likelihood of Future Occurrence

Highly Likely—With respect to the localized, stormwater flood issues, the potential for flooding may increase as storm water is channelized due to land development. Such changes can create localized flooding problems in and outside of natural floodplains by altering or confining natural drainage channels. Urban storm drainage systems have a finite capacity. When rainfall exceeds this capacity or systems clog, water accumulates in the street until it reaches a level of overland release. With older infrastructure, this type of flooding will continue to occur on an annual basis during heavy rains. ANYTHING TO ADD?

Climate Change and Localized Flood

While average annual rainfall may decrease slightly, the intensity of individual rainfall events is likely to increase during the 21st century, increasing the likelihood of overwhelming stormwater systems built to historical rainfall averages. This makes localized flooding more likely.

4.2.14. Hazardous Materials Transport

Hazard/Problem Description

According to the EPA, a hazardous material is any item or agent (biological, chemical, physical) which has the potential to cause harm to humans, animals, or the environment, either by itself or through interaction with other factors. Hazardous materials can be present in any form; gas, solid, or liquid. Environmental or atmospheric conditions can influence hazardous materials if they are uncontained.

The U.S. Occupational Safety and Health Administration’s (OSHA) definition of hazardous material includes any substance or chemical which is a “health hazard” or “physical hazard,” including: chemicals which are carcinogens, toxic agents, irritants, corrosives, sensitizers; agents which act on the hematopoietic system; agents which damage the lungs, skin, eyes, or mucous membranes; chemicals which are combustible, explosive, flammable, oxidizers, pyrophorics, unstable-reactive or water-reactive; and chemicals which in the course of normal handling, use, or storage may produce or release dusts, gases, fumes, vapors, mists or smoke which may have any of the previously mentioned characteristics.

The Environmental Protection Agency (EPA) incorporates the OSHA definition, and adds any item or chemical which can cause harm to people, plants, or animals when released by spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping or disposing into the environment. The EPA maintains a list of 366 chemicals that are considered extremely hazardous substances (EHS). This list was developed under the Superfund Amendments and Reauthorization Act.

Lake County Public Review Draft 4-99 Local Hazard Mitigation Plan Update January 2018 The presence of EHSs in amounts in excess of a threshold planning quantity requires that certain emergency planning activities be conducted.

A release or spill of bulk hazardous materials could result in fire, explosion, toxic cloud or direct contamination of water, people, and property. The effects may involve a local site or many square miles. Health problems may be immediate, such as corrosive effects on skin and lungs, or be gradual, such as the development of cancer from a carcinogen. Damage to property could range from immediate destruction by explosion to permanent contamination by a persistent hazardous material.

Accidents involving the transportation of hazardous materials could be just as catastrophic as accidents involving stored chemicals, possibly more so, since the location of a transportation accident is not predictable. The U.S. Department of Transportation divides hazardous materials into nine major hazard classes. A hazard class is a group of materials that share a common major hazardous property, i.e., radioactivity, flammability, etc. These hazard classes include:

➢ Class 1—Explosives ➢ Class 2—Compressed Gases ➢ Class 3—Flammable Liquids ➢ Class 4—Flammable Solids; Spontaneously Combustible Materials; Dangers When Wet Materials/Water-Reactive Substances ➢ Class 5—Oxidizing Substances and Organic Peroxides ➢ Class 6—Toxic Substances and Infectious Substances ➢ Class 7—Radioactive Materials ➢ Class 8—Corrosives ➢ Class 9—Miscellaneous Hazardous Materials/Products, Substances, or Organisms

Highways and railways constitute a major threat due to the myriad chemicals and hazardous substances, including radioactive materials, transported in vehicles, trucks, and rail cars. Specifically, the Lake County Emergency Operations Plan addresses the transportation of hazardous materials as follows:

Due to extensive agricultural operating, the increasing development of geothermal power plants, gold mining operations and the fact that Highway 20 (the state-designated transportation route between Interstate 5 and Highway 101 for northern California) traverses the County, hazardous materials like to be encountered in Lake County are: pesticides, herbicides, and sundry toxins in solid, liquid, and gaseous form; explosives; petroleum products; flammables; geothermal wastes to include liquid form from drilling sumps and hydrogen sulfide from power plants; chemicals, cyanide and lime from gold mining operations; and low level radioactive wastes. Because of the state-designated route through Lake County, the majority of toxics and radioactive materials that travel from the coast to the central valley traverse Lake County and at several points actually border either Clear Lake or Blue Lakes, producing an extreme vulnerability to water quality.

In addition, while most routes are known, the County has not quantified the amount of hazardous materials that are transported through it en route to adjoining counties.

Lake County Public Review Draft 4-100 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no federal or state disaster declarations for hazardous materials in Lake County.

NCDC Events

The NCDC does not track hazardous materials events.

PHMSA Events

The United States Department of Transportation Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Office of Hazardous Materials Safety performs a range of functions to support the safe transport of hazardous material. One of these functions is the tracking of hazardous materials incidents in the United States. The database was searched for hazardous materials incidents in Lake County. A summary of rail and highway incidents since 1970 in the Lake County Planning Area are shown in Table 4-31. 19 separate events were contained in the database. Incidents where damages or spill amounts were large are discussed after the table.

Table 4-31 Lake County Hazardous Materials Incidents by Jurisdiction and Date

Amount Date of Incident Mode of Transportation Commodity Quantity of Incident Incident City Route Transportation Phase Short Name Released Damages 2/4/1986 Kelseyville – Highway N/A Hazardous 3 gallons $0 Waste Liquid 7/2/1987 Lakeport – Highway N/A Hydrochloric 15 $0 Acid gallons 8/19/1991 Kelseyville No 1 Highway In Transit Sodium 15 $250 Coldwater Hydroxide gallons Creek Geo Solution Pl 12/5/1991 Lakeport 1275 Craig Highway Unloading Sulfuric Acid 3 gallons $205 Ave 1/8/1992 Lower Lake 26775 Highway Unloading Caustic 0.0625 $0 Margan Alkali gallons Valley Road Liquids 2/1/1993 Middletown Sacrats Mine Highway In Transit Hydrogen 94 $5,558 Rd Peroxide gallons 8/15/1995 Kelseyville Highway 29 Highway In Transit Gasoline 1,600 $364,600 gallons 8/13/1996 Clearlake State Hwy Highway In Transit Fuel 3050 $264,634 20 Aviation gallons Turbine

Lake County Public Review Draft 4-101 Local Hazard Mitigation Plan Update January 2018 Amount Date of Incident Mode of Transportation Commodity Quantity of Incident Incident City Route Transportation Phase Short Name Released Damages 1/23/2001 Lakeport 5050 Brush Highway Unloading Petroleum 15 $17 Street Gases gallons Liquefied 10/9/2001 Lakeport Hwy 29 Highway In Transit Gasoline 3,700 $164,070 gallons 2/27/2002 Lakeport 1275 Craig Highway Unloading Corrosive 1 gallons $201 Ave Liquids N.O.S. 9/16/2004 Lakeport Craig Highway In Transit Alcohols 0.03125 $0 Avenue N.O.S. gallons 7/9/2005 Middletown Highway In Transit Gasoline 4,000 $90,000 gallons 9/29/2006 Lakeport 1275 Craig Highway Unloading Caustic 1 gallons $0 Ave. Alkali Liquids 4/21/2009 Santa Rosa 4095 So. Highway Loading Potassium 1 gallons $0 Moorland Hydroxide Ave. 1/12/2010 Kelseyville 5226 4th St. Highway Unloading Kerosene 1.5 $28,713 Span #8 gallons 10/11/2011 Glenhaven Highway In Transit Kerosene 400 $84,480 gallons 1/17/2013 Lakeport 1275 Craig Highway Unloading Hydrogen 1.98135 $0 Ave. Peroxide gallons 12/22/2014 Kelseyville 7405 Highway Unloading Liquefied 0.13368 $0 Sodabay Propane Gas gallons Road Totals $1,002,728 Source: PHMSA Database – Search dates 01/01/1970 – 07/01/2017

August 15, 1995 – The driver was unable to stop in time for stopped traffic. He swerved to avoid hitting the vehicle in front of him causing the trailer to overturn on its side. The driver was suspended and received a post-accident safety briefing. Gasoline was spilled, and there was damage to the vehicles. Damages were estimated at almost $365,000.

August 13, 1996 – a Columbia Helicopters Inc. (CHI) driver lost control of transport vehicle on Hwy 20 and the cargo tank containing jet a rolled over. The friction from the asphalt road wore a hole in the cargo tank. Approximately 3,050 gallons of jet a leaked out of cargo tank. Caltrans & local fire department responded. Fuel reached Grizzly Creek which was almost dry. Fuel traveled approximately 1/2 mile downstream before being stopped by earthen dam created by Caltrans. CHI hired IT Corp. to clean up the spill. It removed remaining free product. CHI had to replace approximately 300 feet of culvert and 80 feet of road way. The creek bed was aerated until sampling revealed acceptable levels. Approximately $265,000 in damages were attributed to this event.

Lake County Public Review Draft 4-102 Local Hazard Mitigation Plan Update January 2018 October 9, 2001 – The driver of a pickup truck crossed over center line and struck a semi head-on. The truck/trailer unit rolled over. 3,700 gallons of gasoline was pilled. Damages from the spill (and resulting clean up) and roll over totaled almost $165,000.

July 9, 2005 – A Gulf truck was traveling north on Hwy 29. A vehicle was making a left turn from a two lane highway. The vehicle was taking a left then decided to turn back into lane. Gulf driver went to the right to miss the vehicle. Trailer tires went on soft shoulder and turned truck over. Truck and trailer landed on its side hole. The Fire department took packing materials and used to stop leak but it still leaked. 4,000 gallons eventually leaked. Damages from the spill and rollover were $90,000.

October 10, 2011 – A driver attempted delivery of heating oil on a dirt road uphill with switchbacks. Roadway gave way under truck, causing it to roll downhill and stop against a tree. Truck ended on its side and leaked fuel from dome cover and vapor system. 400 gallons of fuel oil spilled. Damages from the spill, cleanup costs, and damages to the truck were estimated at almost $85,000.

Hazard Mitigation Planning Committee Events

The HMPC noted the following events:

➢ ANYTHING TO ADD?

Likelihood of Future Occurrence

Likely – Given that 19 hazardous materials incidents have happened in transport through the County in the past 47 years (and many other releases go unreported to national databases), it is likely a hazardous materials incident will occur in Lake County every 5.2 years. However, according to Caltrans, most incidences are related to releases during loading and unloading of cargo, and during transport of fluids from the transporting vehicles themselves and not the cargo. Thus, the likelihood of a significant hazardous materials release within the County is more limited and difficult to predict.

Climate Change and Hazardous Materials

Climate change is unlikely to affect hazardous materials transportation incidents.

4.2.15. Landslides and Debris Flows

Hazard/Problem Description

According to the California Geological Survey, landslides refer to a wide variety of processes that result in the perceptible downward and outward movement of soil, rock, and vegetation under gravitational influence. Common names for landslide types include slump, rockslide, debris slide, lateral spreading, debris avalanche, earth flow, and soil creep. Landslides may be triggered by both natural and human- induced changes in the environment that result in slope instability.

The susceptibility of an area to landslides depends on many variables including steepness of slope, type of slope material, structure and physical properties of materials, water content, amount of vegetation, and

Lake County Public Review Draft 4-103 Local Hazard Mitigation Plan Update January 2018 proximity to areas undergoing rapid erosion or changes caused by human activities. These activities include mining, construction, and changes to surface drainage areas. Landslide events can be determined by the composition of materials and the speed of movement. A rockfall is dry and fast while a debris flow is wet and fast. Regardless of the speed of the slide, the materials within the slide, or the amount of water present in the movement, landslides are a serious natural hazard.

Landslides often accompany other natural hazard events, such as floods, wildfires, or earthquakes. Landslides can occur slowly or very suddenly and can damage and destroy structures, roads, utilities, and forested areas, and can cause injuries and death. POST FIRE DEBRIS FLOW MAPS WILL BE ADDED

The General Plan Background report notes that the major geologic hazard facing the County is that associated with slope instability. Due to the hilly terrain and subsurface geology of the Mesozoic Franciscan Formation, large areas along the Mayacmas Mountains and north of Highway 20 are prone to slope failure. These areas constitute slightly over 40% of the County's area.

The draft 2017 EOP noted that slope instability is greatly affected by slope and geology. Areas on steeper slopes are more susceptible to failing, as a result of heavy rains, excavation, or earthquakes. Slope failures (or landslides) constitute the most widespread geologic hazard in the County. The hills and ridges to the southeast are characterized by very steep slopes and by sharp differences in the strength and stability of the geological materials underlying the surface soils. These differences are generally expressed by the lack or presence of landslide deposits, which are widely but unevenly distributed on the slopes. Most landslide damage has taken place within pre-existing landslide deposits. Lake County could be isolated if State Highway 20, 175, and 29 were impacted by landslides or large debris flow.

Soil erosion is another common form of soil instability. Erosion is a function of soil type, slope, rainfall intensity, and groundcover. It accounts for a loss in many dollars of valuable soil, is aesthetically displeasing, and often induces even greater rates of erosion and sedimentation. Sedimentation is simply the accumulation of soil as a result of erosion. Construction activities often contribute greatly to erosion and sedimentation. Besides being a pollutant in its own right, sediment acts as a transport medium for other pollutants, especially nutrients, pesticides, and heavy metals, which adhere to the eroded soil particles. As the sediment drains into watercourses, the combination of these pollutants adversely affects water quality. Clear Lake water quality suffers from high naturally occurring sedimentation.

Figure 4-37 was developed for the 2013 State of California Multi-Hazard Mitigation Plan. It indicates that most areas throughout Lake County are at moderate to high risk for landslides.

Lake County Public Review Draft 4-104 Local Hazard Mitigation Plan Update January 2018 Figure 4-37 Landslide Susceptibility Areas

Source: 2013 State of California Multi-Hazard Mitigation Plan

Lake County Public Review Draft 4-105 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no disaster declarations associated with landslides in Lake County, as shown in Table 4-4.

NCDC Events

The NCDC contains no records for landslides in Lake County.

Hazard Mitigation Planning Committee Events

The HMPC noted that Clearlake Riviera and Lakeside Heights are areas that have experienced landslides in the past.

In addition, as detailed in the dam failure hazard profile, a past landslide is evident downstream of the Indian Valley Reservoir dam which resulted in a debris impediment upstream of the Spring Valley subdivision. This landslide area, with limited access, may contribute to future flow issues within this area.

The HMPC also noted that Lake Pillsbury has only one serviceable non-paved road to the community and one other road that could service the area could only be passed with an all-terrain vehicle. This is true of Anderson Springs community and the Anderson Springs road. Hwy 20 North of Clearlake Oaks and North of Glenhaven has steep cliff slopes above the highway near the lake. There is slope stability, but there is a few hundred thousand cubic yards that has the potential to slide into the lake and could possibly cause a seiche. There are no previous occurrences of seiche on the lake. The face of the Konocti Mountain has slid off and created the peninsula.

Likelihood of Future Occurrence

Likely—Based on data provided by the HMPC, landslides are naturally occurring events that will inevitably happen as long as gravity itself is a controlling factor upon the landscape. Since Lake County’s mountainous terrain challenges gravity as it rapidly rises to upper elevations, much of the high-relief topography in the county can be identified as land with the potential for landslides. Much of that land though is in remote and undeveloped locales, which reduces the risk of this natural hazard. Given the nature of localized problems identified within the County, landslides will likely continue to impact the area when heavy precipitation occurs, as they have in the past.

Climate Change and Landslide and Debris Flows

According to the CAS, climate change may result in precipitation extremes (i.e., wetter wet periods and drier dry periods). More information on precipitation increases can be found in Section 4.2.3. While total average annual rainfall may decrease only slightly, rainfall is predicted to occur in fewer, more intense precipitation events. The combination of a generally drier climate in the future, which will increase the chance of drought and wildfires, and the occasional extreme downpour is likely to cause more mudslides, landslides, and debris flows.

Lake County Public Review Draft 4-106 Local Hazard Mitigation Plan Update January 2018 4.2.16. Levee Failure

Hazard/Problem Description

A levee is a raised area that runs along the banks of a stream or canal. Levees reinforce the banks and help prevent flooding by containing higher flow events to the main stream channel. By confining the flow to a narrower steam channel, levees can also increase the speed of the water. Levees can be natural or manmade. A natural levee is formed when sediment settles on the stream bank, raising the level of the land around the stream. To construct a man-made levee, workers place dirt or concrete along the stream banks, creating an embankment. This embankment is flat at the top, and slopes at an angle down to the water. For added strength, sandbags are sometimes placed over dirt embankments.

Levees provide strong flood protection, but they are not failsafe. Levees are designed to protect against a specific flood level and could be overtopped during severe weather events or dam failure. Levees reduce, not eliminate, the risk to individuals and structures located behind them.

A levee system failure or overtopping can create severe flooding and high-water velocities. It’s important to remember that no levee provides protection from events for which it was not designed, and proper operation and maintenance are necessary to reduce the probability of failure.

Under-seepage refers to water flowing under the levee through the levee foundation materials, often emanating from the bottom of the landside slope and ground surface and extending landward from the landside toe of the levee. Through-seepage refers to water flowing through the levee prism directly, often emanating from the landside slope of the levee. Both conditions can lead to failure by several mechanisms, including excessive water pressures causing foundation heave and slope instabilities, slow progressing internal erosion, and piping leading to levee slumping.

Rodents burrowing into and compromising the levee system is a significant issue in the Planning Area. Erosion can also lead to levee failure. Figure 4-38 depicts the causes of levee failure.

Lake County Public Review Draft 4-107 Local Hazard Mitigation Plan Update January 2018 Figure 4-38 Potential Causes of Levee Failure

Source: USACE

Overtopping failure occurs when the flood water level rises above the crest of a levee. As shown in Figure 4-39, overtopping of levees can cause greater damage than a traditional flood due to the often lower topography behind the levee.

Figure 4-39 Flooding from Levee Overtopping

Source: Levees in History: The Levee Challenge. Dr. Gerald E. Galloway, Jr., P.E., Ph.D., Water Policy Collaborative, University of Maryland, Visiting Scholar, USACE, IWR.

Lake County Public Review Draft 4-108 Local Hazard Mitigation Plan Update January 2018 Lake County Levees

Agricultural levees were constructed in many areas of Lake County. Most of these agricultural levees only provide protection from the 5 to 20 percent annual chance flood event (20 to 5-year flood). While these levees protect agricultural ground, many rural homes have been constructed in the area “protected” by the levee. Most of the “protected” areas behind these levees are mapped as FEMA floodplains, so the newer homes have flood resistant construction. When these levees fail, the flooding is rapid and deep, as evidenced by the levee failures along Scotts Creek in 1995 and 2005 and Alley Creek in 2005. Because these levees are not maintained by a public agency, their repair is problematic. They generally are not eligible for public disaster funding (FEMA) and responsibility for repair may be placed on the property owner where the levee failure occurred.

Local County Levees

A map of those levees in the County that the County has control over is shown on Figure 4-40. This map includes the Middle Creek left bank (3.35 miles), Middle Creek right bank (2.66 miles), Scotts Creek left bank (1.36 miles), and the Page, Alley, and Clover Creek Diversion right bank (1.49 miles) and left bank (1.03 miles). WHAT ABOUT THOSE BY PUTAH CREEK AS DISCUSSED BELOW?

Lake County Public Review Draft 4-109 Local Hazard Mitigation Plan Update January 2018 Figure 4-40 Lake County – Local Levees Map

Source: Lake County Public Works

Lake County Public Review Draft 4-110 Local Hazard Mitigation Plan Update January 2018 Engineered levees have been constructed to protect the community of Upper Lake and portions of the Hidden Valley Lake Subdivision.

The Lake County Flood Control and Water Conservation District operates and maintains the Middle Creek Flood Control Project in Upper Lake. The project consists of a system of 14.4 miles of levees, a pump station and a diversion channel to divert Clover Creek overflow around the town of Upper Lake. The upper portion of the project protects the community of Upper Lake from flooding by Middle Creek and Clover Creek. The lower portion of the system protects farmland and some residences from inundation by Clear Lake. The draft 2017 EOP noted the following about the Middle Creek Levees:

Located on Middle Creek, Scotts Creek, Clover Creek and Rodman Slough near Upper Lake, the levees are earthen structure and are at risk once the lake reaches 7.56' Rumsey. Once the lake reaches 9.0' Rumsey, Board of Supervisors approval should be sought to create an emergency spillway, and reclamation property owners and operators should be notified. At 10.0' Rumsey residents should be notified to prepare for evacuation in the event of a breach or overflow. Failure of these levees would inundate approximately a 1750 -acre area that has 25 residences and could require or cause closure of the Nice-Lucerne cutoff and Highway 20.

The 2012 LHMP Update noted that the Middle Creek Flood Control Project levees were constructed to reduce the flooding in Upper Lake by the US Army Corps of Engineers (USACE) in 1959. These levees were designed to provide protection to Upper Lake from the 0.5 percent annual chance flood (200-year flood). When the Flood Insurance Study and Flood Insurance Rate Maps (FIRM’s) were prepared by FEMA in the mid-1970’s, these levees upstream of the confluence of Middle and Scotts Creeks were accredited with providing protection to at least the 1% annual chance flood (100-year flood). Since adoption of the FIRM’s, FEMA has adopted regulations establishing criteria for levees to be certified as providing protection the one percent annual chance flood (100-year flood). In 2005, because of the potential for levee failure and the resulting catastrophic flooding, FEMA adopted a policy of remapping levees as non-certified (not providing protection) unless the local community provided evidence that the levee meets the certification criteria.

In 2010, FEMA began the remapping process in Lake County. Based on observations of levee performance in the last 50 years and preliminary engineering analyses, it did not appear that the levees in Upper Lake could be certified as meeting FEMA criteria. There does not appear to be sufficient freeboard in portions of the levee system flood and the area near Highway 20 and Mendenhall Avenue floods frequently from interior drainage, as there is no pump station to pump out local runoff when Middle Creek is at high stage. This will place a majority of the community of Upper Lake within FEMA mapped floodplains by 2012.

The 2014 Preliminary FIS stated that Levees that were shown as providing protection on the 2005 DFIRM Panels and were eligible, were offered the Provisionally Accredited Levee (PAL) option. Levee accreditation data was not provided by Lake County and therefore levees along the following flooding sources were de-accredited in this revision: Middle Creek; Clover Creek and Clover Creek Diversion; Scotts Creek.

As a result of these mapping efforts, there are no certified levees in the Planning Area providing 0.1% level of protection.

Lake County Public Review Draft 4-111 Local Hazard Mitigation Plan Update January 2018 The Middle Creek Flood Control Project levees downstream of the confluence of Middle and Scotts Creeks were subject to multiple failures during construction, and subsequently were not constructed to the design standard. These levees do not provide protection form the one percent annual chance flood (100-year flood) and were not accredited in the FIS and FIRM’s (the floodplain extends behind the levees). The substandard levees provide limited protection (approximately a 28% chance of failure in any given year) to 1,650 acres of agricultural and residential properties. In addition, State Highway 20, the Nice-Lucerne Cutoff, Robinson Rancheria and a major PG&E transmission line are “protected” by the substandard levees. In 1995, the County requested assistance from the USACE to evaluate an ecosystem restoration project in the Upper Lake Reclamation Area to reduce flood risk in the area. Ecosystem restoration (a program created after the 1993 Mississippi River floods) was pursued as it was apparent that conventional flood control measures would not meet favorable benefit-cost criteria. The USACE completed a Reconnaissance Study in 1997, which recommended restoration of the entire area of reclaimed land and three mapped floodplains. A combined Feasibility Study/Environmental Impact Study/Environmental Impact Report (FS/EIS/EIR) was prepared and completed in May 2004. The Project consists of acquiring all properties within the floodplain, demolishing unneeded infrastructure, flood-proofing the electric transmission lines, elevating roadways, building a bridge on the Nice-Lucerne Cutoff, construction of channels with in the project area, breaching the levees and installing pilot plantings. This will restore the area to near its pre-European condition and reduce flood threats. In addition, the Project will provide water quality and habitat benefits. The Lake County Watershed Protection District has acquiring 7 residential properties in the Project area with DWR grant funds. Additional properties will be acquired as funding becomes available. WHAT HAS HAPPENED HERE? PLEASE UPDATE THIS INFORMATION

Levees were constructed when the Hidden Valley Lake subdivision (HVL) was developed in the 1960’s to protect the southeastern part of the subdivision from flooding from Putah Creek. When the FIRM’s were prepared by FEMA in the mid-1970’s, these levees were accredited with providing protection to at least the 1% annual chance flood (100-year flood). During several high runoff events in the 1980’s and 1990’s, homes were flooded behind the levee as runoff from behind the levee accumulated and was not pumped out fast enough. Two repetitive loss properties are located in this area. For this reason, the County requested the area be studied to determine the extent of the floodplain. In 1998, FEMA issued new FIRM’s for several areas including the HVL area. The revised FIRM’s de-accredited the levees and mapped the area based on the worst case levee failure. This now placed 286 residential parcels, all or partially, in the 1% annual chance (100-year) floodplain, where they were not considered in the floodplain prior to 1998. Investigations of the levee shortly afterward confirmed the levee did not meet FEMA levee certification criteria and would cost 3 to 7 million dollars to improve the levee and interior drainage to meet FEMA certification criteria, plus require a public agency assume maintenance responsibility for the levees. Due to the high cost per parcel, no further action was taken to upgrade the levee. WHAT HAPPENED HERE SINCE?

During the creation of the 2014 Preliminary FIS, selected reaches were restudied to apply FEMA policy to a levee built around a subdivision and golf course within the old Coyote Creek floodplain. Coyote Creek diverts around the development before emptying into Putah Creek. An 8-foot-high levee exists on the left banks of both Coyote Creek and Putah Creek. This levee is not certified by any governmental agency. Levee freeboard is less than 3 feet between River Mile (RM) 10.28 and RM 10.46, as well as in the vicinity of RM 11.07. Irrespective of inadequate freeboard, since no public agency maintains the levee system, the

Lake County Public Review Draft 4-112 Local Hazard Mitigation Plan Update January 2018 hydraulic analysis assumed that the left-bank levee along Putah and Coyote Creeks will fail under the 1- percent-annual-chance flood.

In addition, the HMPC noted that a special district in the County has a treated effluent storage reservoir (412 acre feet) that is contained by a levee.

USACE Levees

The US Army Corps of Engineers (USACE) maintains another levee (Maintenance Area 17) in the County, accounting for 3.9 miles of additional levee. The USACE leveed areas are shown on Figure 4-41.

Lake County Public Review Draft 4-113 Local Hazard Mitigation Plan Update January 2018 Figure 4-41 Lake County – Maintenance Area 17 Levees (USACE)

Source: 2012 Sacramento River Individual Agency Summary Reports

Lake County Public Review Draft 4-114 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Disaster Declaration History

There have been no disasters declarations related to levee failure in Lake County, as shown on Table 4-4

NCDC Events

There have been no NCDC levee failure events in Lake County.

Hazard Mitigation Planning Committee Events

Scotts Creek in 1995 and 2005 and Alley Creek in 2005. CAN WE GET INFO ON THESE AND ANY OTHERS? THESE WERE FROM THE OLD PLAN

Likelihood of Future Occurrence

Likely – Due to the number and age of levees in Lake County, future levee failures are currently considered likely.

Climate Change and Levee Failure

In general, increased flood frequency in California is a predicted consequence of climate change. Mechanisms whereby climate change leads to an elevated flood risk include more extreme precipitation events and shifts in the seasonal timing of river flows. This threat may be particularly significant because recent estimates indicate the additional force exerted upon the levees is equivalent to the square of the water level rise. These extremes are most likely to occur during storm events, leading to more severe damage from waves and floods.

4.2.17. Subsidence

Hazard/Problem Description

Land subsidence is defined as the sinking of the land over man-made or natural underground voids. Subsidence can result in serious structural damage to buildings, roads, irrigation ditches, underground utilities, and pipelines. It can disrupt and alter the flow of surface or underground water. Weight, including surface developments such as roads, reservoirs, and buildings and manmade vibrations from such activities as blasting or heavy truck or train traffic can accelerate the natural processes of subsidence. In Lake County, there are generally two types of subsidence of concern: subsidence from groundwater pumping and the settling of the ground over abandoned mine workings (i.e., the creation of sinkholes). Karst may also happen in the County, but it is of lesser concern.

Groundwater Pumping

Severe groundwater overdraft may lead to subsidence, a permanent lowering of the ground surface due to consolidation of sediments. Water is a necessity for ranchers raising beef cattle, growing vineyards and

Lake County Public Review Draft 4-115 Local Hazard Mitigation Plan Update January 2018 orchard crops or farmers growing annual truck crops. Livestock must be supplied with water and crops must be irrigated.

Fluctuations in the level of underground water caused by pumping or by injecting fluids into the earth can initiate sinking to fill the empty space previously occupied by water or soluble minerals. The consequences of improper use of land subject to ground subsidence can be excessive economic losses, including the high costs of repair and maintenance for buildings, irrigation works, highways, utilities, and other structures. This results in direct economic losses to citizens as well as indirect economic losses through increased taxes and decreased property values.

Abandoned Mines

Past mining activities have created surface subsidence in some areas and have created the potential for subsidence in other areas. Lake County is home to many abandoned mines. Mines and mining, always dangerous while in operation, posed new dangers when abandoned. Airshafts were left exposed or covered by a few boards. They are typically holes of 4 to 10 feet in diameter on the surface, extending hundreds of feet down to the mine tunnels below. Access shafts were often covered hurriedly by closing off the mine mouth (entrance) with logs, then backfilling with rock and earth. In time, the forgotten but reclaimed site sprouted vegetation, hiding a large hole lurking perhaps as little as 8 to 10 feet below the surface. Figure 4-42 shows abandoned mines in and around Lake County.

Lake County Public Review Draft 4-116 Local Hazard Mitigation Plan Update January 2018 Figure 4-42 Abandoned Mines in Lake County

Source: California Department of Conservation, Office of Mine Reclamation

Lake County Public Review Draft 4-117 Local Hazard Mitigation Plan Update January 2018 Karst

Distinctive surficial and subterranean features developed by solution of carbonate and other rocks and characterized by closed depressions, sinking streams, and cavern openings are commonly referred to as karst. Originally the term defined surface features derived by solution of carbonate rocks, but subsequent use has broadened the definition to include sulfates, halides, and other soluble rocks. The term has been expanded also to cover interrelated forms derived by solution on the surface in the subsurface. Fortunately for Lake County, very little karst exists in the County.

Past Occurrences

Disaster Declaration History

There have been no disaster declarations related to subsidence in Lake County.

NCDC Events

The NCDC database shows no past occurrences of subsidence.

Hazard Mitigation Planning Committee Events

ANY EVENTS TO ADD?

Likelihood of Future Occurrence

Occasional—Soil subsidence (or sinkholes) due to mining activity has historically been seen as an outcome of the mining activity that occurred in the history of Lake County. Given the number of mines in the County, there does exist the possibility of future subsidence. The General Plan Background Report noted that the likelihood of local subsidence problems occurring due to extraction of geothermal resources appears remote. Substantial subsidence due to local geothermal development has not been noted to date. However, geothermal development has only occurred in areas of Lake County characterized by dry steam resources at relatively deep locations. Development of liquid dominated geothermal resources, particularly in residential and agricultural areas, would require careful monitoring to insure that subsidence problems do not occur.

Climate Change and Subsidence

Climate change is unlikely to change the causes of subsidence (abandoned mines, karst, and groundwater pumping) in the County. However, data is showing that the groundwater table is lowering causing subsidence in California which can be compounded by the changes in precipitation and periods of drought.

Lake County Public Review Draft 4-118 Local Hazard Mitigation Plan Update January 2018 4.2.18. Volcano (and geothermal gases)

Hazard/Problem Description

The California State Hazard Mitigation Plan identifies volcanoes as one of the hazards that can adversely impact the State. However, there have been few losses in California from volcanic eruptions. Of the approximately 20 volcanoes in the State, only a few are active and pose a threat. Of these, the Clear Lake Volcano poses a threat to Lake County. According to the USGS, the Clear Lake volcanic field lies in the northern Coast Ranges, California. The volcanic field consists of lava dome complexes, cinder cones, and maars of basaltic-to-rhyolitic composition. Mount Konocti, a dacitic lava dome on the south shore of Clear Lake, is the largest volcanic feature. The area has intense geothermal activity, caused by a large, still hot silicic magma chamber about 14 km wide and 7 km beneath the surface. It provides the heat source for the Geysers, the world's largest producing geothermal field on the SW side of the volcanic field. Its geothermal power plants can generate approximately 2000 megawatts, enough to power two cities the size of San Francisco. The latest volcanic activity happened about 10,000 years ago and formed maars and cinder cones along the shores of Clear Lake, the largest natural freshwater lake in California. Volcanism around Clear Lake is related to the complex San Andreas transform fault system. Figure 4-43 shows volcanoes in or near California and the location of the Clear Lake area relative to the Lake County Planning Area.

Lake County Public Review Draft 4-119 Local Hazard Mitigation Plan Update January 2018 Figure 4-43 Active Volcanoes in California and in the Lake County Area

Source: 2013 State of California Hazard Mitigation Plan

As shown in Figure 4-44, active volcanoes pose a variety of natural hazards. Explosive eruptions blast lava fragments and gas into the air with tremendous force. The finest particles (ash) billow upward, forming an eruption column that can attain stratospheric heights in minutes. Simultaneously, searing volcanic gas laden with ash and coarse chunks of lava may sweep down the flanks of the volcano as a pyroclastic flow. Ash in the eruption cloud, carried by the prevailing winds, is an aviation hazard and may remain suspended for

Lake County Public Review Draft 4-120 Local Hazard Mitigation Plan Update January 2018 hundreds of miles before settling to the ground as ash fall. During less energetic effusive eruptions, hot, fluid lava may issue from the volcano as lava flows that can cover many miles in a single day. Alternatively, a sluggish plug of cooler, partially solidified lava may push up at the vent during an effusive eruption, creating a lava dome. A growing lava dome may become so steep that it collapses, violently releasing pyroclastic flows potentially as hazardous as those produced during explosive eruptions.

Figure 4-44 Volcanoes and Associated Hazards

Source: USGS Publication 2014-3120

During and after an explosive or effusive eruption, loose volcanic debris on the flanks of the volcano can be mobilized by heavy rainfall or melting snow and ice, forming powerful floods of mud and rock (lahars) resembling rivers of wet concrete. These can rush down valleys and stream channels as one of the most destructive types of volcano hazards.

Lake County Public Review Draft 4-121 Local Hazard Mitigation Plan Update January 2018 Populations living near volcanoes are most vulnerable to volcanic eruptions and lava flows, although volcanic ash can travel and affect populations many miles away and cause problems for aviation. The USGS notes specific characteristics of volcanic ash. Volcanic ash is composed of small jagged pieces of rocks, minerals, and volcanic glass the size of sand and silt, as shown in Figure 4-45. Very small ash particles can be less than 0.001 millimeters across. Volcanic ash is not the product of combustion, like the soft fluffy material created by burning wood, leaves, or paper. Volcanic ash is hard, does not dissolve in water, is extremely abrasive and mildly corrosive, and conducts electricity when wet.

Figure 4-45 Ash Particle from 1980 Mt. St Helens Eruption Magnified 200 Times

Source: US Geological Survey: Volcanic Ash: Effect & Mitigation Strategies. http://volcanoes.usgs.gov/ash/properties.html.

Volcanic ash is formed during explosive volcanic eruptions. Explosive eruptions occur when gases dissolved in molten rock (magma) expand and escape violently into the air, and also when water is heated by magma and abruptly flashes into steam. The force of the escaping gas violently shatters solid rocks. Expanding gas also shreds magma and blasts it into the air, where it solidifies into fragments of volcanic rock and glass. Once in the air, wind can blow the tiny ash particles tens to thousands of miles away from the volcano.

The average grain-size of rock fragments and volcanic ash erupted from an exploding volcanic vent varies greatly among different eruptions and during a single explosive eruption that lasts hours to days. Heavier, large-sized rock fragments typically fall back to the ground on or close to the volcano and progressively smaller and lighter fragments are blown farther from the volcano by wind. Volcanic ash, the smallest particles (2 mm in diameter or smaller), can travel hundreds to thousands of kilometers downwind from a volcano depending on wind speed, volume of ash erupted, and height of the eruption column.

The size of ash particles that fall to the ground generally decreases exponentially with increasing distance from a volcano. Also, the range in grain size of volcanic ash typically diminishes downwind from a volcano

Lake County Public Review Draft 4-122 Local Hazard Mitigation Plan Update January 2018 (becoming progressively smaller). At specific locations, however, the distribution of ash particle sizes can vary widely.

The impact of coarse air fall is limited to the immediate area of the volcanic vent. Structures may be damaged by accumulation of falling lava fragments or burnt by their high heat. Wildfires may be ignited by coarse ash. Although generally non‐lethal, fine ash fall is the most widespread and disruptive volcanic hazard. People exposed to fine ash commonly experience various eye, nose, and throat symptoms. Short‐ term exposures are not known to pose a significant health hazard. Long‐term health effects have not been demonstrated conclusively. Ash deposited downwind of the volcano covers everything like a snowfall, but also infiltrates cracks and openings in machinery, buildings, and electronics. Falling ash can obscure sunlight, reducing visibility to zero. When wet, it can make paved surfaces slippery and impassable. Fine ash is abrasive, damaging surfaces and moving parts of machinery, vehicles, and aircraft. Life‐threatening and costly damage can occur to aircraft that fly through fine ash clouds. Newly fallen volcanic ash may result in short‐term physical and chemical changes in water quality. Close to the volcano, heavy ash fall may cause roofs to collapse, waste water systems to clog, and power systems to shut down. In agricultural areas, fine ash can damage crops, and sicken livestock. Resuspension of ash by human activity and wind cause continuing disruption to daily life.

In addition, the area of Lake County where Clearlake is located has numerous geothermal sources and mineral springs that release gases through surface vents. Hydrogen sulfide, carbon dioxide and methane gases leach out from underground magma through hot springs and during volcanic activity. Hydrogen Sulfide is a flammable, colorless gas that has a characteristic smell of rotten eggs at low concentrations. Once released, H2S can remain in the atmosphere for an estimated 18 hours. The World Health

Organization recommends that exposure to H2S be avoided. Children are readily affected by H2S because it is heavier than air; the gas accumulates in poorly ventilated, low-lying areas and travels along the ground. At concentration between 0.00011–0.00033 ppm no health effects have been found in humans. Exposure to higher concentrations may trigger eye and nose irritation as well as breathing difficulties in asthmatics. Most people can tolerate exposure levels up to 20 ppm for some hours without any harm. At 500 ppm victims will look intoxicated and at 700 ppm, H2S will cause loss of consciousness and death if the victim is not resuscitated within three minutes. Survivors suffer from long term, or permanent health effects, such as headaches, poor motor function, poor memory and poor attention span. The scope and magnitude of the problem are not well understood, nor are the health risks to residents who may experience low level and/or intermittent exposures. Engineering efforts to mitigate the worst areas of gas release through filtration and venting have been only partially successful. A thorough geologic study of the area is needed in order to better understand the nature and scope of the risk and the mitigation measures that could be appropriately applied.

Past Occurrences

Disaster Declarations

There have been no disaster declarations related to volcano.

Lake County Public Review Draft 4-123 Local Hazard Mitigation Plan Update January 2018 NCDC Events

The NCDC does not track volcanic activity.

Hazard Mitigation Planning Committee Events

The HMPC noted no volcanic events. However, there have been numerous past events of geothermal gas releases. The HMPC noted that in early 2010, the spontaneous localized release of toxic and explosive levels of hydrogen sulfide and methane gases from the soil in a residential neighborhood in the City of Clearlake posed a danger that had not been identified in nearly twenty years. One household was evacuated as a result of these gases. These gases continue to be detected to varying degrees. OTHERS? CAN WE GET SOME IDEA OF THE FREQUENCY AND SEVERITY OF THESE GAS RELEASES?

USGS Events

The Clear Lake Volcanics erupted during four periods of time beginning at about 2 million years ago. There is a general decrease in age northward from 2 million years ago in the south to about 10,000 years in the north. Geophysical data suggests there is currently a spherical to cylindrical magma chamber about 8.7 miles in diameter and about 4.3 mi from the surface. Seismic studies indicate that the vertical extent is approximately 18.6 miles deep.

4 eruptive episodes have been recognized: 2.1-1.3 million years ago, 1.1-0.8 million years ago, 0.65-0.30 million years ago., and 100,000-10,000 years ago. These can be seen on Figure 4-46. The total volume of about 100 individual eruptions exceeds 70 cubic kilometers. Eruptive products from the first activity episode are found in the east of the field. The second activity episode constructed Cobb Mountain (1 million years ago) and Mount Hannah (0.9 million years ago). The third episode of activity was at the Mount Konocti–Thurston Lake area, the most voluminous dacite and rhyolite feature of the Clear Lake volcanics. The most recent activity, up to about 10,000 years ago were small mostly basaltic and andesitic eruptions in the north of the field.

Lake County Public Review Draft 4-124 Local Hazard Mitigation Plan Update January 2018 Figure 4-46 Clear Lake – Past Eruptions

Source: USGS *Ma = million years ago

Likelihood of Future Occurrences

Unlikely—According to the USGS, the complex eruptive history over the past 2 million years and the 10,000-year age of the youngest eruption indicate that the Clear Lake magmatic system is not extinct and that future eruptions are likely. Such a long period of multiple volcanic events and the large volume (approximately 1,400 km3, 335 mi3) magma chamber suggest that the Clear Lake system could be in pre- caldera early evolutionary stage. Although future eruptions are likely in the Clear Lake field, prediction of the timing is difficult because activity has been episodic in the past. From dates and numbers of ash beds beneath Clear Lake, and the apparent lack of eruptions in the past 10,000 years is a geologically brief lull in activity after frequent eruptions (about 34, or averaging one every 1,800 years) in the previous 60,000 years. Episodes of volcanic activity have typically continued for at least 300,000 years, so that the youngest episode, which began about 100,000 years ago could be in an early stage and may continue for another 200,000 years. Eruptions are likely to be located close to, beneath, or northeast of Clear Lake, especially around the east arm of the lake. Phreatomagmatic eruptions would occur near the lake and would pose ash- fall and wave hazards to the lakeshore and ash-fall hazards to areas within a few kilometers of the vent. Eruptions away from the lake would produce cinder cones and flows and would be hazardous within a few kilometers of the vents.

4.2.19. Wildfire

Hazard/Problem Description

California is recognized as one of the most fire‐prone and consequently fire‐adapted landscapes in the world. The combination of complex terrain, Mediterranean climate, and productive natural plant communities, along with ample natural and aboriginal ignition sources, has created conditions for extensive Lake County Public Review Draft 4-125 Local Hazard Mitigation Plan Update January 2018 wildfires. Wildland fire is an ongoing concern for the Lake County Planning Area. Generally, the fire season extends from early spring through late fall of each year during the hotter, dryer months. However, in recent years, wildfire season is more of a year long event. Fire conditions arise from a combination of high temperatures, low moisture content in the air and fuel, an accumulation of vegetation, and high winds.

Potential losses from wildfire include human life, structures and other improvements, natural and cultural resources, quality and quantity of water supplies, cropland, timber, and recreational opportunities. Economic losses could also result. Smoke and air pollution from wildfires can be a severe health hazard. In addition, catastrophic wildfire can create favorable conditions for other hazards such as flooding, landslides, and erosion during the rainy season. AFTER ACTION REPORTS WILL BE ADDED. POST FIRE DEBRIS FLOW MAPS AS WELL.

Wildland Urban Interface

Throughout California, communities are increasingly concerned about wildfire safety as increased development in the foothills and mountain areas and subsequent fire control practices have affected the natural cycle of the ecosystem. While wildfire risk is predominantly associated with wildland urban interface (WUI) areas, significant wildfires can also occur in heavily populated areas. The wildland urban interface is a general term that applies to development adjacent to landscapes that support wildland fire. The WUI defines the community development into the foothills and mountainous areas of California. The WUI describes those communities that are mixed in with grass, brush and timbered covered lands (wildland). These are areas where wildland fire once burned only vegetation but now burns homes as well. The WUI for Lake County consists of communities at risk (shown in Table 4-77 in Section 4.2.18) as well as the area around the communities that pose a fire threat.

There are two types of WUI environments. The first is the true urban interface where development abruptly meets wildland. The second WUI environment is referred to as the wildland urban intermix. Wildland urban intermix communities are rural, low density communities where homes are intermixed in wildland areas. Wildland urban intermix communities are difficult to defend because they are sprawling communities over a large geographical area with wild fuels throughout. This profile makes access, structure protection, and fire control difficult as fire can freely run through the community.

WUI fires are often the most damaging. WUI fires occur where the natural and urban development intersect. Even relatively small acreage fires may result in disastrous damages. WUI fires occur where the natural forested landscape and urban‐built environment meet or intermix. The damages are primarily reported as damage to infrastructure, built environment, loss of socio‐economic values and injuries to people.

The pattern of increased damages is directly related to increased urban spread into historical forested areas that have wildfire as part of the natural ecosystem. Many WUI fire areas have long histories of wildland fires that burned only vegetation in the past. However, with new development, a wildland fire following a historical pattern now burns developed areas. WUI fires can occur where there is a distinct boundary between the built and natural areas or where development or infrastructure has encroached or is intermixed in the natural area. WUI fires may include fires that occur in remote areas that have critical infrastructure easements through them, including electrical transmission towers, railroads, water reservoirs,

Lake County Public Review Draft 4-126 Local Hazard Mitigation Plan Update January 2018 communications relay sites or other infrastructure assets. Human impact on wildland areas has made it much more difficult to protect life and property during a wildland fire. This home construction has created a new fuel load within the wildland and shifted firefighting tactics to life safety and structure protection.

Lake County Wildfires

Wildland fires affect grass, forest, and brushlands, as well as any structures located within them. Where there is human access to wildland areas the risk of fire increases due to a greater chance for human carelessness and historical fire management practices. Generally, there are four major factors that sustain wildfires and allow for predictions of a given area’s potential to burn. These factors include fuel, topography, weather, and human actions.

➢ Fuel – Fuel is the material that feeds a fire and is a key factor in wildfire behavior. Fuel is generally classified by type and by volume. Fuel sources are diverse and include everything from dead tree leaves, twigs, and branches to dead standing trees, live trees, brush, and cured grasses. Also to be considered as a fuel source are manmade structures, such as homes and other associated combustibles. The type of prevalent fuel directly influences the behavior of wildfire. Fuel is the only factor that is under human control. The 2016 Strategic Fire Plan for Sonoma-Lake-Napa Unit describes the fuels in the County. There are a wide range of fuels in Lake County. Fuels range from Tule wetland and grass/oak woodland to decadent chaparral, to mixed conifer forests. The higher elevations are generally timbered while lower elevations tend to be chaparral or grassy oak woodland. Due to aggressive fire suppression tactics and lack of wildland fuels reduction, both the vertical arrangement and horizontal continuity of fuels will promote rapid fire growth. Where disked vineyards have been established in place of chaparral brush fields they can act as effective fuel breaks. Where vineyards have gone fallow, left untended, the fire will still spread through the vineyard. Critical concerns are when the chaparral dead-to-live ratio exceeds 50%, and live fuel moisture drops to near 60% in late summer and early fall. ➢ Topography – An area’s terrain and land slopes affect its susceptibility to wildfire spread. Both fire intensity and rate of spread increase as slope increases due to the tendency of heat from a fire to rise via convection. The arrangement of vegetation throughout a hillside can also contribute to increased fire activity on slopes. The 2016 Strategic Fire Plan noted that elevation within Lake County ranges from 1,500 feet near lake level to peaks reaching 5,000 to 7,000 feet on the Mendocino National Forest. The topography consists of broad rounded trending ridges running North/South splitting around Clearlake. Slopes generally increase as you go from ridgeline to drainage bottom. Steep slopes, drainages and timber fuels can significantly hinder firefighting efforts. Vineyards, roads and other manmade features provide a limited network of barriers that assist firefighting efforts. Road access off of well-developed county roads can be sketchy at times with rough, narrow, often steep and rocky roads. ➢ Weather – Weather components such as temperature, relative humidity, wind, and lightning also affect the potential for wildfire. High temperatures and low relative humidity dry out fuels that feed wildfires, creating a situation where fuel will ignite more readily and burn more intensely. Thus, during periods of drought, the threat of wildfire increases. Wind is the most treacherous weather factor. The greater a wind, the faster a fire will spread and the more intense it will be. In addition to wind speed, wind shifts can occur suddenly due to temperature changes or the interaction of wind with topographical features such as slopes or steep hillsides. Lightning also ignites wildfires, often in difficult to reach terrain for firefighters. The 2016 Strategic Fire Plan noted that in Lake County, the weather is generally warm and dry during the day with good relative humidity recovery at night. Mid slope elevations may see

Lake County Public Review Draft 4-127 Local Hazard Mitigation Plan Update January 2018 poor humidity recovery due to inversions. Critical weather patterns are generally those that have higher temperatures and dryer conditions with poor nighttime humidity recovery such as north and east winds. When these conditions combine with the topography, expect extreme rates of spread, especially along exposed ridges and through constricted areas. Peak summer day temperatures generally range from 90- 110F, with relative humidity ranging between 10 – 25%. Temperatures and humidity moderate and winds tend to increase immediately adjacent to Clearlake. Gradient winds are generally out of the west or northwest at 5-10 mph, ➢ Human Actions – Most wildfires are ignited by human action, the result of direct acts of arson, carelessness, or accidents. Many fires originate in populated areas along roads and around homes, and are often the result of arson or careless acts such as the disposal of cigarettes, use of equipment or debris burning. Recreation areas that are located in high fire hazard areas also result in increased human activity that can increase the potential for wildfires to occur.

Wildfire Environment of Lake County, California

The 2008 Lake County Community Wildfire Protection Plan (CWPP) noted much about the wildfire environment on the County. From the grasslands and chaparral to the pine/oak woodlands and conifer forests, it is generally believed today that fires in the rural landscape of Lake County are less frequent and more severe compared to the patterns present before Europeans settled the area. This region evolved with fire, and fire will continue to shape it. Much of the vegetation in the county is adapted to, meaning it has evolved with, fire. For example, ponderosa pine (Pinus ponderosa) and incense cedar (Calocedrus decurrens) both produce very thick bark with age, helping them to withstand the heat of low and moderate intensity fire.

Lake County is no exception to the increasingly common problem of property loss and habitat destruction from wildfire. Fuel loads have been accumulating to unnaturally high levels throughout the region due to decades of fire suppression and prevalent land-management practices. This has led to an increase in large, catastrophic wildfires. In 2008, fire protection agencies responded to 687 fires in Lake County. One of the largest fires that year was the Walker Fire, burning a total of 14,500 acres in the Walker Ridge area near Colusa County. It started at the same time as the extensive lightning strike fires burned throughout northern California, stressing local fire protection resources. Further, in 2012 the Wye Fire burned in Lake and Colusa County, consuming 7,394 acres. In 2015, due to drought conditions that occurred throughout California, other major fires occurred: the Valley Fire and and Rocky Fire. These fires caused major damage. In 2016, the Clayton Fire caused large damages in the County as well (more information on these can be found in the past occurrences section of this hazard profile)

One of the tools used to predict fire behavior based on vegetation type is called “fuel models.” Fuel models give fire managers a general idea of the type of vegetation that can be found in a given area, and how it is expected to burn. Of the standard 13 fuel models identified in California by CAL FIRE, eight can be found in Lake County. They are: Grass, Pine/Grass, Tall Chaparral, Light Brush, Intermediate Brush, Hardwood/Conifer Light, Medium Conifer, and Heavy Conifer (see Figure 4-47).

Lake County Public Review Draft 4-128 Local Hazard Mitigation Plan Update January 2018 Figure 4-47 Lake County – Fuel Models

Source: 2008 Lake County CWPP

Lake County Public Review Draft 4-129 Local Hazard Mitigation Plan Update January 2018 Fuel models are combined with topographic slope and fuel density information to provide a fuel hazard assessment of fire behavior under extreme conditions. CAL FIRE’s recent Fire Hazard Severity Zones (FHSZ) analysis is based on fuels, terrain, and weather. Most of Lake County’s wildland areas are mapped within Very High Fire Hazard Severity Zones, as are the communities of Nice, Lucerne, the Rivieras, Cobb, Lake Pillsbury, and a few others. However, most of the County’s residents live in High or Moderate FHSZs around Clear Lake and the valleys.

Another tool used to understand fire is “fire regime.” Fire regime is a measurement of fire’s historic natural occurrence in the landscape. It includes the season, frequency, intensity, and spatial distribution of fire. In other words, it models how often fire historically would burn through a certain place and at what intensity. A standardized set of five fire regimes is used nationwide. There are two pre-settlement fire regimes found in Lake County: Fire Regime I—a natural fire-return interval between 0–35 years of low-severity fire, and Fire Regime III—a frequency of between 35–100 years of mixed-severity fire.

The difference in fire regime between pre- and post-European settlement is described by the “condition class,” or degree of departure from the historical natural fire regime. The greater the departure from the natural fire regime, the greater the variations to ecological components and the higher the risk of losing key ecosystem components. All three condition class levels (of low, moderate, and high departure from historical conditions) are present in Lake County. The largest area in Lake County (at 45%) contains those ecosystems with a low departure from their natural fire regime, and hence low risk of key ecosystem loss. Another 22% are at a moderate departure. Those areas with a significant departure and high risk of ecosystem loss, are 20% of the county lands, and located primarily in the mountainous regions of the north and south. Finally, 13% are not classified because they are not wildlands. For more information on fire regime and condition class, see Figure 4-48 and Figure 4-49.

Lake County Public Review Draft 4-130 Local Hazard Mitigation Plan Update January 2018 Figure 4-48 Lake County – Fire Regime Class

Source: 2008 Lake County CWPP

Lake County Public Review Draft 4-131 Local Hazard Mitigation Plan Update January 2018 Figure 4-49 Lake County – Fire Condition Class

Source: 2008 Lake County CWPP

Lake County Public Review Draft 4-132 Local Hazard Mitigation Plan Update January 2018 Past Occurrences

Past occurrences of fire in the County are quite numerous. There are also numerous sources that capture portions of these past occurrences. This section uses disaster declarations, NCDC events, CAL FIRE events, 2016 Fire Plan, and 2008 CWPP events to paint the picture of past occurrences of wildfire. Events not captured by these plans and databases are then supplemented by the HMPC.

Disaster Declaration History

A search of FEMA and Cal OES disaster declarations turned up multiple events. These are shown in Table 4-32.

Table 4-32 Lake County – State and Federal Disaster Declaration from Wildfire 1950-2017

Disaster Type Federal Declarations State Declarations Count Years Count Years Fire 7 1985, 1996, 2012, 2015 (three 1 1987 times), 2016 Totals 7 – 1 – Source: Cal OES, FEMA

NCDC Events

The NCDC has tracked wildfire events in the County dating back to 1993. The 10 events in Lake County are shown in Table 4-33.

Table 4-33 NCDC Wildfire Events in Lake County 1993 to 3/31/2017

Date Event Injuries Deaths Property Crop Injuries Deaths (direct) (direct) Damage Damage (direct) (direct) 6/12/2008 Wildfire 0 0 $0.00 $0.00 0 0 6/21/2008 Wildfire 0 0 $0.00 $0.00 0 0 7/1/2008 Wildfire 0 0 $0.00 $0.00 0 0 9/7/2009 Wildfire 0 0 $0.00 $0.00 4 0 7/11/2014 Wildfire 1 21 $0.00 $0.00 0 0 7/29/2015 Wildfire 0 0 $0.00 $0.00 0 0 8/1/2015 Wildfire 0 0 $0.00 $0.00 0 0 8/9/2015 Wildfire 0 0 $0.00 $0.00 0 0 9/12/2015 Wildfire 4 4 $0.00 $0.00 0 0 8/13/2016 Wildfire 0 0 $1,500,000.00 $0.00 0 0 Totals 0 27 $500,000,000 $0 12 0 Source: NCDC *Deaths, injuries, and damages are for the entire event, and may not be exclusive to the County.

Lake County Public Review Draft 4-133 Local Hazard Mitigation Plan Update January 2018 CAL FIRE Events

CAL FIRE, USDA Forest Service Region 5, Bureau of Land Management (BLM), the National Park Service (NPS), Contract Counties and other agencies jointly maintain a comprehensive fire perimeter GIS layer for public and private lands throughout the state. The data covers fires back to 1878 (though the first recorded incident for the County was in 1917). For the National Park Service, Bureau of Land Management, and US Forest Service, fires of 10 acres and greater are reported. For CAL FIRE, timber fires greater than 10 acres, brush fires greater than 50 acres, grass fires greater than 300 acres, and fires that destroy three or more residential dwellings or commercial structures are reported. CAL FIRE recognizes the various federal, state, and local agencies that have contributed to this dataset, including USDA Forest Service Region 5, BLM, National Park Service, and numerous local agencies.

Fires may be missing altogether or have missing or incorrect attribute data. Some fires may be missing because historical records were lost or damaged, fires were too small for the minimum cutoffs, documentation was inadequate, or fire perimeters have not yet been incorporated into the database. Also, agencies are at different stages of participation. For these reasons, the data should not be used for statistical or analytical purposes.

The data provides a reasonable view of the spatial distribution of past large fires in California. Using GIS, fire perimeters that intersect Lake County were extracted and are listed in summary in Table 4-34, and in detail in Appendix E. There are 415 fires recorded in this database for Lake County greater than 50 acres. Each of them was tracked by CAL FIRE. Appendix E lists each fire’s date, cause code, name, total acreage burned, and acreage burned in Lake County. Many more small fires have occurred, but were not included in the analysis.

Figure 4-50 shows fire history for the County, colored by the size of the acreage burned. This map contains fires from 1950 to 2016, while the detailed tables of wildfire shown in Appendix E contain fires from 1910 to 2016, though the first recorded wildfire in this database in Lake County is from 1916.

Lake County Public Review Draft 4-134 Local Hazard Mitigation Plan Update January 2018 Figure 4-50 Lake County Wildfire History – CAL FIRE 1910 to 2016

Lake County Public Review Draft 4-135 Local Hazard Mitigation Plan Update January 2018 Table 4-34 Lake County – Wildfire History Summary by Cause 1910-2016

Cause of Fire Fire Count Fire Area (in Acres) Lightning 23 101,610.3 Equipment Use 25 93,849.9 Smoking 2 587.0 Campfire 10 39,397.9 Debris 14 16,167.6 Arson 31 244,257.8 Miscellaneous 37 231,044.5 Vehicle 6 12,113.3 Powerline 8 2,316.2 Unknown / Unidentified 257 619,086.6 Escaped Prescribed Burn 2 362.0 Lake County Total 415 1,360,793.1 Source: CAL FIRE

2008 CWPP Events

The fire history of an area is a description of the time, space, and cause of fires in the area. In fire jargon, “fire risk” is often associated with fire history, as this term describes the events that cause a fire to start (i.e. ignitions).

Fire history is important because it illustrates the potential for future fires. Large fires often repeat themselves; thus, it is useful to understand burning patterns over time. An area’s fire history also portrays ignition patterns that can target effective prevention programs. For example, if there is a history of frequent fires along a well-traveled route, roadside vegetation management may be in order. Additionally, fire history discerned through fire scars on tree rings may indicate the way fires have changed over time, both in frequency and intensity. This may point to appropriate goals for future fuel conditions.

Fire Caused by Natural Lightning

Lightning fires in northern California, including Lake County, are common in the summer and fall months, particularly in the higher elevations where strikes are more likely to occur. Fires ignite when lightning strikes coincide with rainless, windy weather; however, lightning fires rarely occur in the spring. Lightning fires pose a significant threat to Lake County and its many communities, especially during dry lightning events where burning conditions are met.

In the summer of 2008, over 2,000 fires burned throughout Northern California as a result of thunderstorms and dry conditions that occurred from the coast to the Sierra Nevada. Approximately 4,046 acres burned within Lake County at that time. These fires, fueled by extremely dry vegetation, quickly overwhelmed fire-fighting resources as they burned through thousands of acres. Lake County, as well as much of the rest of Northern California, experienced unhealthy, smoky days for a long period of time (over a month in some Northern California communities). When lightning starts multiple fires, suppression resources may not be

Lake County Public Review Draft 4-136 Local Hazard Mitigation Plan Update January 2018 adequate or available for new fires. This occurred in June of 2008 when the Walker Fire (see below) started in the middle of the lightning fire siege of Northern California. The Walker Fire was understaffed for many days while resources were committed elsewhere.

Native American Period Fire History

It is widely understood that during the pre-settlement period, Native Americans used fire as a resource management tool throughout California and the West. In fact, “When Spanish explorer Juan Rodriguez Cabrillo anchored in San Pedro Bay in October of 1542, it was the chaparral fires that gave him the signal that the coast was occupied by humans. A succession of explorers, missionaries, and settlers thereafter would continually note the ‘smoky air’ from these fires in their journals in every corner of the state – in the coastal redwood forests, the tule marshes of the Delta, the southern oak woodlands, the mixed conifer forests, and the northern hazelnut flats”.

The use of fire as a tool ranged from plant cultivation and land clearing to mast production and hunting. For example, in Lake County the native Pomo burned bracken fern patches to enhance them; the new fronds were eaten and the rhizomes used to create basket designs. The acreage burned by California’s earliest humans was significant; fire scientists Robert Martin and David Sapsis estimate that 5.6 to 13 million acres of California burned annually under both lightning and indigenous people’s fire regimes. However, fire scientist Scott Stephens, Sapsis, and others have now estimated lower numbers. They estimate that 4,447,896 acres burned annually in California prior to 1800, excluding the southwestern deserts.26 This estimate of prehistoric annual area burned in California is 88% of the total annual “extreme” wildfire area burned in the entire United States within a single decade (1994–2004). From 1950 to 1999, the average annual area burned by wildfire in all vegetation types in California was approximately 25,2047 acres/yr, only approximately 5.6% of what traditionally burned in a similar timeframe. Regardless of errors in either estimation, prior to modern fire suppression very large amounts of land burned in California. Skies were likely smoky much of the summer and fall in California during this period.

European Settlement Fire History

During European settlement, logging—primarily of the largest, oldest trees—became common, with subsequent changes in forest structure and fuel volumes. Many forms of land management during this era (such as logging, grazing, development, and most notably fire suppression) have influenced the fire history of Lake County.

As a result of large destructive fires in the West and Midwest in the early part of the 1900’s, the perception of fire as a beneficial tool, such as seen by Native Americans, was overlooked and instead viewed as a major threat to lives, property, and natural resources. The outcome of this viewpoint was the “10 a.m. policy” adopted by the US Forest Service in 1935. This policy sought to aggressively suppress fires and have them extinguished by 10 a.m. the morning following a fire being discovered. This type of land management activity (intensive fire suppression), combined with increased development, a resulting lack of homeowner defensible space, logging of the largest trees, etc., has led to an increase in the amount of flammable materials now accumulated within Lake County. Today it is widely accepted that fires now burn longer and hotter than those prior to European settlement.

Lake County Public Review Draft 4-137 Local Hazard Mitigation Plan Update January 2018 Post European Settlement Fire History to 2008

During the last century, fire history has changed dramatically. Forest fuels have changed through more modern cultural practices of timber harvesting, mining, and grazing. Fire control in the west, including Lake County, has been extremely effective, particularly since the 1930’s. Wildfire now escapes less than two percent of the time—but those escaped fires cause the vast majority of damage.

Lake County fire history shows that there have been several major wildland-urban interface (WUI) fires. In the autumn of 1961, a 9,000+-acre fire burned through the Cobb Mountain area, destroying several structures. In the fall of 1964, the South County region again was subject to a 52,000-acre fire known as the Hanley Fire that started near the Lake/Napa County border northwest of Calistoga. This wildland fire ultimately burned all the way to the city limits of Santa Rosa, approximately forty miles southwest. That same year, a 15,000-acre wildland fire started at the Lake County dump (possibly the result of the past practice of burning garbage at the dump) and threatened the community of Middletown. In the fall of 1968, the Lower Lake area was subject to a 10,000-acre wildland fire. In 1981, the Lang Peak Fire consumed 11,000 acres. In 1981, the Cow Mountain Fire traveled eastward from the Bureau of Land Management (BLM) lands near Ukiah in Mendocino County and burned to the foothills near Lakeport. In 1985 an interface fire burned through the Hidden Valley residential community, leaving significant property damage. The Mendenhall Fire burned approximately 70,000 acres in Lake and Mendocino Counties in 1987, while the Fouts Fire burned 19,000 acres in Lake and Colusa Counties.

The most recent large fires in Lake County have been the 1996 Fork Fire, the 2001 Trough Fire, and the 2008 Walker Fire. The Fork Fire started on the southern end of the Mendocino National Forest and burned 83,000 acres and eleven structures. The fire threatened the northern shore of Clear Lake, including the communities of Nice and Lucerne, and burned east almost to the Colusa County line. The Trough Fire started in eastern Colusa County at an intersection of U.S Forest Service roads in heavy brush and moved into Lake County. This fire burned through 24,970 acres, including portions of the Snow Mountain Wilderness. The most recent large fire—the Walker Fire—started on June 22, 2008. The likely source of this fire was a vehicle being driven near Indian Valley Reservoir hitting a rock with its metal undercarriage. This fire burned 14,500 remote acres in the eastern portion of Lake County.

Figure 4-52 and Figure 4-51 show Lake County fire history, both by the decade in which the fire occurred, and by the ignition source (where known). This is useful to compare fire history both temporally and by cause.

Lake County Public Review Draft 4-138 Local Hazard Mitigation Plan Update January 2018 Figure 4-51 Lake County – Fire History by Decade 1920 to 2008

Source: 2008 Lake County CWPP Lake County Public Review Draft 4-139 Local Hazard Mitigation Plan Update January 2018 Figure 4-52 Lake County – Fire History by Ignition Source 1920 to 2008

Source: 2008 Lake County CWPP

Lake County Public Review Draft 4-140 Local Hazard Mitigation Plan Update January 2018 Hazard Mitigation Planning Committee

The HMPC noted that fire has played a significant historical role in defining the current vegetative strata in Lake County.

➢ 2012 Wye Fire – The Wye Fire burned 7,934 acres in Lake and Colusa counties. Challenging fire behavior, low reality humidity, very high temperatures, and erratic winds contributed to the spread of the fire. The fire burned an area around Highway 20 east of Highway 53 and in the Clearlake Oaks area. The smoke from the fires could be seen for miles. It could be seen from Napa County from the south and Butte County from the north. The fire destroyed two structures and one outbuilding. In addition, two other structures were damaged. 3 injuries were attribute to this fire. At its peak, more that 1,250 fire personnel from multiple agencies were involved in the fire fight. Multiple evacuation orders were put out. The Wye Fire resulted in a federal disaster declaration (FM-5004). ➢ 2015 Rocky Fire – The Rocky Fire was a wildfire that burned in Lake County, California during the 2015 California wildfire season. The fire, which ignited July 29, burned 69,438 acres, destroying 43 residences and 53 outbuildings before it was contained on August 14. On August 12 Cal Fire officials confirmed that the fire had merged with the Jerusalem Fire which was burning to the south. On August 19 investigators from Cal Fire determined that the fire had been caused by a faulty gas-powered water heater inside an outbuilding. Multiple evacuation orders were put forth for areas near Morgan Valley Road and Rocky Creek Road. Fortunately, no injuries or deaths were reported. ➢ 2015 Valley Fire – The Valley Fire was a wildfire during the 2015 California wildfire season that started on September 12 in Lake County, California. The fire started shortly after 1:00 pm near Cobb and by 6:30 PM had burned more than 10,000 acres. The fire quickly spread into Middletown and Hidden Valley, threatening northern Sonoma County around The Geysers, and northern Napa County, approaching Pope Valley and Angwin. On September 12, mandatory evacuation orders were issued for Cobb, Middletown, Loch Lomond, Harbin Hot Springs, Hidden Valley Lake, the Clearlake Riviera, Riviera West, and Soda Bay communities of unincorporated parts of Kelseyville, Pope Valley and Angwin. By midnight of the first day, scores of homes and businesses had been destroyed in Middletown, along with at least 50 homes in Cobb as well as the entire Hoberg’s Resort, an historic retreat built in the 1880s. The resort community of Harbin Hot Springs was also destroyed. Evacuation centers were established in the town of Kelseyville to the northwest and Calistoga to the southeast. By September 13, the fire had reached 50,000 acres and had destroyed much of Cobb, Middletown, Whispering Pines, and parts in the south end of Hidden Valley Lake. High winds spread the fire very quickly. The fire ultimately spread to 76,067 acres, killed four people and destroyed nearly 2,000 buildings. At the time, the fire wass the third-worst fire in California history, based on the total structures burned. A Cal Fire investigation pointed to faulty wiring of a hot tub installation as the cause of the fir. ➢ 2016 Clayton Fire – The Clayton Fire was a wildfire that started on August 13, 2016 just south of Lower Lake in Lake County, California. The fire was first reported at 6:03 pm on August 13 near Highway 29 and Clayton Creek Road. By August 14, the second day, 10 homes had been destroyed and up to 6,000 people had been evacuated from Lower Lake and Clearlake, including St. Helena Hospital Clearlake. An evacuation center was opened at Highlands Senior Center and was evacuated the following day. By August 15, the third day, 5 percent of the fire had been contained, burning a total of 3,000 acres, 175 buildings, including the offices of a Habitat for Humanity affiliate, had been destroyed and 1,044 fire personnel were on the ground. Road closures were announced throughout the area, including Clayton Creek Road at Highway 29, Morgan Valley Road, North Spruce Grove Road at Spruce Grove Road,

Lake County Public Review Draft 4-141 Local Hazard Mitigation Plan Update January 2018 and Jerusalem Grade South Spruce Grove Road. State Route 53 at Highway 29 is closed. New evacuation centers were opened at Twin Pine Casino, Kelseyville High School, and the Seventh-day Adventist Church in Lakeport. By August 16, the fourth day, 1,664 fire personnel were on the ground and 20 percent of the fire had been contained. It was reported, at the time, as burning a total of 4,000 acres. Additionally, the Clearlake area of the Avenues and neighborhoods from Polk Avenue to Cache Creek, east of Highway 53, had been evacuated. A state of emergency was declared for Lake County by California Governor Jerry Brown. On the fifth day, August 17, road closures remained and evacuation centers also remained open, with 40 percent of the fire being contained, burning a total of 3,929 acres, and 2,327 fire personnel were on the ground. By August 24, the fire was 98 percent contained and has burned a total of 3,929 acres and has destroyed 300 buildings. A construction worker from Clearlake was arrested and faced 17 counts of arson related to the Clayton Fire and other fires.

Likelihood of Future Occurrence

Highly Likely — From May to October of each year, Lake County faces a serious wildland fire threat. Fires will continue to occur on an annual basis in the Lake County Planning Area. The threat of wildfire and potential losses are constantly increasing as human development and population increase and the wildland urban interface areas expand. Due to its high fuel load and long, dry summers, most of Lake County continues to be at risk from wildfire.

Climate Change and Wildfire

Warmer temperatures can exacerbate drought conditions. Drought often kills plants and trees, which serve as fuel for wildfires. Warmer temperatures could increase the number of wildfires and pest outbreaks, such as the western pine beetle. Cal-Adapt’s wildfire tool predicts the potential increase in the amount of burned areas for the year 2085, as compared to recent (2010) conditions. This is shown in Figure 4-53. Based on this model, Cal-Adapt predicts that wildfire risk in Lake County will increase slightly in the near term, and subside during mid-to late-century. However, wildfire models can vary depending on the parameters used. Cal-Adapt does not take landscape and fuel sources into account in their model. In all likelihood, in Lake County, precipitation patterns, high levels of heat, topography, and fuel load will determine the frequency and intensity of future wildfire.

Lake County Public Review Draft 4-142 Local Hazard Mitigation Plan Update January 2018 Figure 4-53 Lake County – Project Increase in Wildfire Burn Areas

Source: Cal-Adapt

4.2.20. Natural Hazards Summary

Table 4-35 summarizes the results of the hazard identification and hazard profile for the Lake County Planning Area based on the hazard identification data and input from the HMPC. For each hazard profiled in Section 4.2, this table includes the likelihood of future occurrence and whether the hazard is considered a priority hazard for the Lake County Planning Area.

Table 4-35 Hazard Identification/Profile Summary and Determination of Priority Hazards

Hazard Likelihood of Future Occurrence Priority Hazard Agricultural Hazards Highly Likely Y Aquatic Biologic Hazards: cyanobacterial bloom Highly Likely Y Aquatic Biologic Hazards: quagga mussel Likely Y Climate Change Likely Y Dam Failure Occasional Y Drought and Water Shortage Likely Y Earthquake Likely Y Flood: 1%/0.2% Annual Chance Occasional/Unlikely Y Flood: Localized/Stormwater Likely Y Hazardous Materials Likely Y Landslide and Debris Flows Likely Y Levee Failure Likely Y

Lake County Public Review Draft 4-143 Local Hazard Mitigation Plan Update January 2018 Hazard Likelihood of Future Occurrence Priority Hazard Severe Extreme Heat Likely Y Severe Weather: Heavy Rains, Snow, and Storms Highly Likely (winds, hail, lightning) Y Severe Weather: High Winds Highly Likely Y Subsidence Occasional N Volcano (and geothermal gases) Unlikely Y Wildfire Highly Likely Y

Lake County Public Review Draft 4-144 Local Hazard Mitigation Plan Update January 2018 4.3 Vulnerability Assessment

Requirement §201.6(c)(2)(ii): [The risk assessment shall include a] description of the jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section. This description shall include an overall summary of each hazard and its impact on the community.

Requirement §201.6(c)(2)(ii)(A): The plan should describe vulnerability in terms of the types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas.

Requirement §201.6(c)(2)(ii)(B): [The plan should describe vulnerability in terms of an] estimate of the potential dollar losses to vulnerable structures identified in paragraph (c)(2)(i)(A) of this section and a description of the methodology used to prepare the estimate.

Requirement §201.6(c)(2)(ii)(C): [The plan should describe vulnerability in terms of] providing a general description of land uses and development trends within the community so that mitigation options can be considered in future land use decisions.

With Lake County’s hazards identified and profiled, the HMPC conducted a vulnerability assessment to describe the impact that each hazard would have on the County. The vulnerability assessment quantifies, to the extent feasible using best available data, assets at risk to natural hazards and estimates potential losses. This section focuses on the vulnerabilities of the Lake County Planning Area (i.e., unincorporated Lake County) as a whole.

This vulnerability assessment followed the methodology described in the FEMA publication Understanding Your Risks—Identifying Hazards and Estimating Losses. The vulnerability assessment first describes the total vulnerability and assets at risk and then discusses vulnerability by hazard.

Data Sources

Data used to support this assessment included the sources listed below. Where data and information from these studies, plans, reports, and other data sources were used, the source is referenced as appropriate throughout this vulnerability assessment. :

➢ CAL FIRE GIS datasets ➢ USFS GIS datasets ➢ County staff ➢ ArkStorm at Tahoe - Stakeholder Perspectives on Vulnerabilities and Preparedness for an Extreme Storm Event in the Greater Lake Tahoe, Reno and Carson City Region. 2014. ➢ California Adaptation Planning Guide ➢ Cal-Adapt ➢ Cal-IPC ➢ CAL FIRE GIS datasets ➢ CalTrans, Truck Networks on California State Highways. 2015. ➢ California Department of Conservation

Lake County Public Review Draft 4-145 Local Hazard Mitigation Plan Update January 2018 ➢ California Department of Finance, E-1 Report ➢ California Department of Finance, E-4 Report ➢ California Department of Finance, P-1 Report ➢ California Department of Fish and Wildlife’s Natural Diversity Database ➢ California Department of Food and Agriculture ➢ California Department of Water Resources Best Available Maps ➢ California Department of Water Resources DAC Mapping Tool ➢ California Department of Water Resources Division of Safety of Dams ➢ California Native Plant Society ➢ California Natural Diversity Database – BIOS Viewer Tool ➢ California Office of Emergency Services – Dam Inundation Data ➢ California Office of Historic Preservation ➢ Climate Change and Health Profile Report – Lake County ➢ Existing plans and studies ➢ Final Clear Lake Watershed Sanitary Survey 2012 Update ➢ FEMA’s HAZUS-MH 2.2 GIS-based inventory data ➢ FEMA Digital Flood Insurance Rate Map. ➢ FEMA Madera County Flood Insurance Study. ➢ Kenward, Alyson PhD, Adams-Smith, Dennis, and Raja, Urooj. Wildfires and Air Pollution – The Hidden Health Hazards of Climate Change. Climate Central. 2013. ➢ Liu, J.C., Mickley, L.J., Sulprizio, M.P. et al. Climatic Change. 138: 655. doi:10.1007/s10584-016- 1762-6. 2016. ➢ Lake County Assessor’s Office ➢ Lake County Building Department ➢ Lake County Digital Flood Insurance Rate Map ➢ Lake County Emergency Operations Plan ➢ Lake County Flood Insurance Study (2005 Adopted and Preliminary 2014) ➢ Lake County Flood Management Plan ➢ Lake County GIS data ➢ Lake County General Plan ➢ Lake County General Plan Environmental Impact Report ➢ Lake County Housing Element ➢ National Drought Mitigation Center – Drought Impact Reporter ➢ National Levee Database ➢ National Park Service – Historic American Buildings Survey and Historic American Engineering Record ➢ Personal interviews with planning team members and staff from the County and participating jurisdictions ➢ Proceedings of the National Academy of Sciences ➢ Public Health Alliance of Southern California ➢ Statewide GIS datasets from other agencies such as Cal OES, FEMA, USGS, CGS, Cal Atlas, and others ➢ University of California ➢ US Census Bureau 2010 Household Population Estimates ➢ US Fish and Wildlife Service ➢ US Fish and Wildlife Service’s National Wetlands Inventory maps

Lake County Public Review Draft 4-146 Local Hazard Mitigation Plan Update January 2018 ➢ US Geological Survey ➢ US Geological Survey Landslide Maps ➢ Written descriptions of inventory and risks provided by Lake County ➢ Personal interviews and discussions with planning team members and staff from the County and participating jurisdictions

4.3.1. Lake County Vulnerability and Assets at Risk

As a starting point for analyzing the Lake County Planning Area’s vulnerability to identified hazards, the HMPC used a variety of data to define a baseline against which all disaster impacts could be compared. If a catastrophic disaster was to occur in the Planning Area, this section describes significant assets at risk in the Planning Area. Data used in this baseline assessment included:

➢ Total values at risk; ➢ Critical facility inventory; ➢ Cultural, historical, and natural resources; and ➢ Growth and development trends.

Total Values at Risk

Parcel Inventory and Assessed Values

This analysis captures the values associated with assessed assets located within the Lake County. The 2017 GIS parcel layer and the Lake County Assessor data, dated 1/3/2017, obtained from Lake County, was used for the basis of this analysis. This data provided by Lake County represents best available data.

Understanding the total assessed value of Lake County is a starting point to understanding the overall value of identified assets at risk in the County. When the total assessed values are combined with potential values associated with other community assets such as area populations, public and private critical infrastructure, historic and cultural resources, and natural resources, the big picture emerges as to what is potentially at risk and vulnerable to the damaging effects of natural hazards within the County.

Methodology

Lake County’s 2017 Assessor Data and the County’s GIS parcel data were used as the basis for the inventory of assessed values for both improved and unimproved parcels within the County. This data provides the land and improved values assessed for each parcel. Other GIS data, such as jurisdictional boundaries, roads, streams, and area features, was also obtained from Lake County to support countywide mapping and analysis of assets at risk. The Countywide Lake County GIS parcel data contained 64,118 parcels, including the areas of the City of Clearlake, City of Lakeport, and the unincorporated areas of Lake County. This plan focuses on the unincorporated Lake County area as the Planning Area for this effort, and therefore the GIS parcel data specific to the Lake County Planning Area contained 47,206 parcels.

Analysis is first provided in this section for the entire Lake County broken out by incorporated Lake County and its two incorporated communities. Hazard specific analyses contained in the remainder of this Plan were not conducted for the incorporated communities as they were not participating jurisdictions for this

Lake County Public Review Draft 4-147 Local Hazard Mitigation Plan Update January 2018 planning effort. They are only included here to provide an overview of parcels and values contained within the geographic boundaries of Lake County. All other analysis contained in this plan is specific to the Lake County Planning Area, which includes the unincorporated County and its 18 communities detailed in Table 4-36.

Table 4-36 Lake County (unincorporated) Communities

Communities Clearlake Lucerne Kelseyville Clearlake Park Nice Lakeport Finley Whispering Pines Lower Lake Hidden Valley Lake Clearlake Oaks Middletown Lake Pillsbury Cobb Upper Lake Loch Lomond Glenhaven Witter Springs Source: Lake County

Data Limitations & Notations

Although based on best available data, the resulting information should only be used as an initial guide to overall values in the County. In the event of a disaster, structures and other infrastructure improvements are at the greatest risk of damage. Depending on the type of hazard and resulting damages, the land itself may not suffer a significant loss. For that reason, the values of structures and other infrastructure improvements are of greatest concern. Also, it is critical to note a specific limitation to the assessed values data within the County, created by Proposition 13. Instead of adjusting property values annually, no adjustments are made until a property transfer occurs. As a result, overall property value information is most likely low and may not reflect current market or true potential loss values for properties within the County.

The 2017 GIS parcel and Assessor data (Table M) was obtained to perform the spatial analysis. The initial Table M contained 65,351 records. The initial GIS parcel data contained 64,118 records. When the assessor table was linked to the GIS parcel attribute table, there were 64,118 successful record matches. GIS was used to compare parcel polygons and parcel centroids, or points, representing the center of each parcel polygon. For the purposes of this analysis, the centroids which were not coincident in locations were re- positioned to overlay on the corresponding polygons so that each assessor record (with a unique assessor parcel number) was spatially positioned on the corresponding parcel. In addition, multiple parcels polygons in the GIS data were constructed as multi-part features, of which only one centroid was representative of each parcel polygon. Thus, in some instances, the position of the centroids may result in less accurate hazard analysis overlay results for approximately 120 of these records. The data did not contain duplicate records. In total, 64,118 records were utilized for the analysis.

Property Use Categories

Lake County provided a Zoning dataset containing a base zoning code which provide detailed descriptive information about how each property is generally used, such as residential, commercial, or industrial. The

Lake County Public Review Draft 4-148 Local Hazard Mitigation Plan Update January 2018 zoning codes were refined and categorized into the following property use categories and linked back to the Lake County Assessor data. The final property use categories for the Lake County include:

➢ Agricultural ➢ Commercial ➢ Industrial ➢ Open Space/Rural Lands ➢ Residential ➢ Unknown

Once Use Codes were grouped into categories, the number of total and improved parcels and land and improved values were inventoried for the County and jurisdictions by property use.

Estimated Content Replacement Values

Lake County’s assigned property use categories were used to develop estimated content replacement values (CRVs) that are potentially at loss from hazards. FEMA’s standard CRV factors were utilized to develop more accurate loss estimates for all mapped hazard analyses. FEMA’s CRV factors estimate value as a percent of improved structure value by property use. Table 4-37 shows the breakdown of the different property uses in Nevada and their estimated CRV factors.

Table 4-37 Lake County – Content Replacement Factors by Property Use

Lake County Property Hazus Property Use Hazus Content Use Categories Categories Replacement Values Agricultural Agricultural 100% Commercial Commercial 100% Industrial Industrial 150% Open Space / Rural Lands Agricultural 100% Residential Residential 50% Unknown Other 100% Source: Hazus

Lake County Values at Risk Results

Values at Risk without Contents

Values associated with land, and improved structure values were identified and summed to determine total assessed values at risk in the Lake County Planning Area. Together, the land value and improved structure value make up the majority of assessed values associated with each identified parcel or asset. Improved parcel counts were based on the assumption that a parcel was improved if a structure value was present. Information on other values such as personal property values were not readily available for inclusion in this effort.

Table 4-38 shows the total values or exposure for the entire Lake County geographic area, by jurisdiction. This includes unincorporated Lake County, which for purposes of the plan is the Lake County Planning

Lake County Public Review Draft 4-149 Local Hazard Mitigation Plan Update January 2018 Area, in addition to the two incorporated communities. With the exception of this table which is included to provide an understanding of all assets by jurisdiction that are located within the geographic county boundaries, all other analysis data and tables is specific to the Lake County Planning Area (Unincorporated County).

The values for the Lake County Planning Area are broken out by property use type and are provided in Table 4-39.

Table 4-38 Lake County (unincorporated County) and Incorporated Communities – Total Values at Risk by Jurisdiction

Property Use Total Parcel Improved Total Land Improved Total Value Count Parcel Count Value Structure Value Unincorporated 47,206 22,900 $2,044,169,239 $2,956,943,629 $5,001,112,868 Lake County City of Clearlake 14,484 7,189 $268,596,049 $521,148,239 $789,744,288 City of Lakeport 2,428 2,015 $158,715,482 $310,085,351 $468,800,833 Total 64,118 32,104 $2,471,480,770 $3,788,177,219 $6,259,657,989 Source: Lake County 1/3/2017 Parcel/Assessor’s Data

Table 4-39 Lake County – Total Values at Risk by Property Use

Total Parcel Improved Parcel Total Land Improved Property Use Count Count Value Structure Value Total Value Agricultural 2,438 1,562 $250,288,855 $228,964,355 $479,253,210 Commercial 1,698 1,086 $141,004,647 $267,683,150 $408,687,797 Industrial 40 27 $6,673,010 $11,970,324 $18,643,334 Open Space / 5,534 1,425 $408,134,763 $326,517,853 $734,652,616 Rural Lands Residential 37,493 18,800 $1,238,067,964 $2,121,807,947 $3,359,875,911 Unknown 3 0 $0 $0 $0 Total 47,206 22,900 $2,044,169,239 $2,956,943,629 $5,001,112,868 Source: Lake County 1/3/2017 Parcel/Assessor’s Data

As detailed in Chapter 1, there are 18 unincorporated communities that make up the unincorporated County or Lake County Planning Area. Table 4-40 breaks out the Lake County Planning Area into the 18 communities to show values at risk by community.

Table 4-40 Lake County – Total Values at Risk by Unincorporated Communities

Unincorporated Total Parcel Improved Total Land Improved Total Value Communities Count Parcel Count Value Structure Value Clearlake 132 40 $15,978,129 $4,861,835 $20,839,964 Clearlake Oaks 5,327 2,675 $196,917,653 $245,812,342 $442,729,995 Clearlake Park 1,228 503 $48,601,864 $48,891,936 $97,493,800

Lake County Public Review Draft 4-150 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Total Value Communities Count Parcel Count Value Structure Value Cobb 2,039 1,182 $67,839,321 $93,446,318 $161,285,639 Finley 199 175 $15,887,876 $20,458,154 $36,346,030 Glenhaven 213 149 $14,197,369 $16,585,888 $30,783,257 Hidden Valley Lake 3,552 2,523 $95,993,179 $398,565,604 $494,558,783 Kelseyville 8,136 5,224 $472,831,295 $790,205,691 $1,263,036,986 Lake Pillsbury 972 196 $19,504,919 $17,049,902 $36,554,821 Lakeport 3,450 2,462 $286,558,896 $431,912,367 $718,471,263 Loch Lomond 775 473 $30,515,523 $40,780,072 $71,295,595 Lower Lake 2,902 1,713 $234,224,354 $184,553,151 $418,777,505 Lucerne 9,262 1,684 $124,136,922 $149,860,628 $273,997,550 Middletown 2,281 1,289 $201,117,200 $273,845,029 $474,962,229 Nice 4,099 1,277 $81,607,576 $112,920,386 $194,527,962 Upper Lake 2,111 1,074 $112,619,103 $106,031,170 $218,650,273 Whispering Pines 349 154 $9,728,770 $7,287,256 $17,016,026 Witter Springs 179 107 $15,909,290 $13,875,900 $29,785,190 Total 47,206 22,900 $2,044,169,239 $2,956,943,629 $5,001,112,868 Source: Lake County 1/3/2017 Parcel/Assessor’s Data

Values at Risk with Contents

Table 4-41 shows the total values of the Lake County Planning Area as shown in Table 4-40, but with estimated content replacement values (CRVs) included (using CRV multipliers from Table 4-37). This table is important as potential losses to the County include structure contents. In addition, loss estimates contained in the hazard vulnerability sections of this Chapter will use calculations based on the total values, including content replacement values.

Table 4-41 Lake County – Total Values at Risk by Property Use with Content Replacement Values

Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Clearlake Agricultural 4 1 $330,254 $914,474 $914,474 $2,159,202 Commercial 2 0 $324,880 $0 $0 $324,880 Industrial 1 1 $152,287 $664,988 $997,482 $1,814,757 Open Space / 79 16 $11,331,328 $1,506,457 $1,506,457 $14,344,242 Rural Lands Residential 43 22 $3,839,380 $1,775,916 $887,958 $6,503,254 Unknown 3 0 $0 $0 $0 $0

Lake County Public Review Draft 4-151 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Clearlake Total 132 40 $15,978,129 $4,861,835 $4,306,371 $25,146,335 Clearlake Oaks Agricultural 86 35 $11,436,951 $19,607,537 $19,607,537 $50,652,025 Commercial 175 129 $14,367,870 $17,890,159 $17,890,159 $50,148,188 Industrial 0 0 $0 $0 $0 $0 Open Space / 924 239 $51,459,237 $27,565,820 $27,565,820 $106,590,877 Rural Lands Residential 4,142 2,272 $119,653,595 $180,748,826 $90,374,413 $390,776,834 Unknown 0 0 $0 $0 $0 $0 Clearlake Oaks 5,327 2,675 $196,917,653 $245,812,342 $155,437,929 $598,167,924 Total Clearlake Park Agricultural 0 0 $0 $0 $0 $0 Commercial 7 1 $228,619 $776,792 $776,792 $1,782,203 Industrial 0 0 $0 $0 $0 $0 Open Space / 7 2 $832,800 $184,690 $184,690 $1,202,180 Rural Lands Residential 1,214 500 $47,540,445 $47,930,454 $23,965,227 $119,436,126 Unknown 0 0 $0 $0 $0 $0 Clearlake Park 1,228 503 $48,601,864 $48,891,936 $24,926,709 $122,420,509 Total Cobb Agricultural 9 2 $74,547 $440,615 $440,615 $955,777 Commercial 36 23 $2,822,834 $4,061,572 $4,061,572 $10,945,978 Industrial 0 0 $0 $0 $0 $0 Open Space / 188 66 $11,106,695 $7,600,418 $7,600,418 $26,307,531 Rural Lands Residential 1,806 1,091 $53,835,245 $81,343,713 $40,671,857 $175,850,815 Unknown 0 0 $0 $0 $0 $0 Cobb Total 2,039 1,182 $67,839,321 $93,446,318 $52,774,462 $214,060,101 Finley Agricultural 151 132 $14,200,278 $17,863,125 $17,863,125 $49,926,528 Commercial 17 15 $861,533 $1,172,457 $1,172,457 $3,206,447 Industrial 0 0 $0 $0 $0 $0 Open Space / 0 0 $0 $0 $0 $0 Rural Lands Residential 31 28 $826,065 $1,422,572 $711,286 $2,959,923

Lake County Public Review Draft 4-152 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Unknown 0 0 $0 $0 $0 $0 Finley Total 199 175 $15,887,876 $20,458,154 $19,746,868 $56,092,898 Glenhaven Agricultural 0 0 $0 $0 $0 $0 Commercial 31 29 $3,705,972 $2,901,948 $2,901,948 $9,509,868 Industrial 0 0 $0 $0 $0 $0 Open Space / 26 9 $2,608,499 $3,423,524 $3,423,524 $9,455,547 Rural Lands Residential 156 111 $7,882,898 $10,260,416 $5,130,208 $23,273,522 Unknown 0 0 $0 $0 $0 $0 Glenhaven 213 149 $14,197,369 $16,585,888 $11,455,680 $42,238,937 Total Hidden Valley Lake Agricultural 0 0 $0 $0 $0 $0 Commercial 3 0 $0 $0 $0 $0 Industrial 0 0 $0 $0 $0 $0 Open Space / 46 0 $18,838 $0 $0 $18,838 Rural Lands Residential 3,503 2,523 $95,974,341 $398,565,604 $199,282,802 $693,822,747 Unknown 0 0 $0 $0 $0 $0 Hidden Valley 3,552 2,523 $95,993,179 $398,565,604 $199,282,802 $693,841,585 Lake Total Kelseyville Agricultural 608 481 $76,656,595 $70,938,644 $70,938,644 $218,533,883 Commercial 261 172 $26,316,082 $46,001,208 $46,001,208 $118,318,498 Industrial 11 8 $1,769,157 $3,247,620 $4,871,430 $9,888,207 Open Space / 516 176 $51,813,940 $34,331,370 $34,331,370 $120,476,680 Rural Lands Residential 6,740 4,387 $316,275,521 $635,686,849 $317,843,425 $1,269,805,795 Unknown 0 0 $0 $0 $0 $0 Kelseyville 8,136 5,224 $472,831,295 $790,205,691 $473,986,077 $1,737,023,063 Total Lake Pillsbury Agricultural 44 3 $454,457 $130,860 $130,860 $716,177 Commercial 2 0 $154,806 $0 $0 $154,806 Industrial 0 0 $0 $0 $0 $0 Open Space / 479 37 $10,120,257 $1,740,865 $1,740,865 $13,601,987 Rural Lands

Lake County Public Review Draft 4-153 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Residential 447 156 $8,775,399 $15,178,177 $7,589,089 $31,542,665 Unknown 0 0 $0 $0 $0 $0 Lake Pillsbury 972 196 $19,504,919 $17,049,902 $9,460,814 $46,015,635 Total Lakeport Agricultural 557 400 $57,594,166 $55,924,269 $55,924,269 $169,442,704 Commercial 147 121 $20,034,457 $85,812,485 $85,812,485 $191,659,427 Industrial 6 4 $711,045 $1,666,653 $2,499,980 $4,877,678 Open Space / 398 115 $27,396,754 $18,848,975 $18,848,975 $65,094,704 Rural Lands Residential 2,342 1,822 $180,822,474 $269,659,985 $134,829,993 $585,312,452 Unknown 0 0 $0 $0 $0 $0 Lakeport Total 3,450 2,462 $286,558,896 $431,912,367 $297,915,701 $1,016,386,964 Loch Lomond Agricultural 38 6 $688,742 $482,993 $482,993 $1,654,728 Commercial 15 10 $1,418,178 $1,183,235 $1,183,235 $3,784,648 Industrial 0 0 $0 $0 $0 $0 Open Space / 104 45 $7,942,604 $5,778,783 $5,778,783 $19,500,170 Rural Lands Residential 618 412 $20,465,999 $33,335,061 $16,667,531 $70,468,591 Unknown 0 0 $0 $0 $0 $0 Loch Lomond 775 473 $30,515,523 $40,780,072 $24,112,542 $95,408,137 Total Lower Lake Agricultural 230 132 $32,982,597 $20,066,082 $20,066,082 $73,114,761 Commercial 132 76 $14,312,139 $16,253,993 $16,253,993 $46,820,125 Industrial 1 0 $50,929 $0 $0 $50,929 Open Space / 829 237 $80,684,824 $33,985,718 $33,985,718 $148,656,260 Rural Lands Residential 1,710 1,268 $106,193,865 $114,247,358 $57,123,679 $277,564,902 Unknown 0 0 $0 $0 $0 $0 Lower Lake 2,902 1,713 $234,224,354 $184,553,151 $127,429,472 $546,206,977 Total Lucerne Agricultural 20 2 $510,673 $577,733 $577,733 $1,666,139 Commercial 215 155 $12,944,678 $17,283,113 $17,283,113 $47,510,904 Industrial 0 0 $0 $0 $0 $0

Lake County Public Review Draft 4-154 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Open Space / 350 32 $17,350,732 $2,904,542 $2,904,542 $23,159,816 Rural Lands Residential 8,677 1,495 $93,330,839 $129,095,240 $64,547,620 $286,973,699 Unknown 0 0 $0 $0 $0 $0 Lucerne Total 9,262 1,684 $124,136,922 $149,860,628 $85,313,008 $359,310,558 Middletown Agricultural 88 47 $12,803,732 $10,815,617 $10,815,617 $34,434,966 Commercial 191 158 $17,090,002 $26,528,574 $26,528,574 $70,147,150 Industrial 16 10 $3,062,426 $5,445,874 $8,168,811 $16,677,111 Open Space / 758 235 $91,883,907 $163,939,143 $163,939,143 $419,762,193 Rural Lands Residential 1,228 839 $76,277,133 $67,115,821 $33,557,911 $176,950,865 Unknown 0 0 $0 $0 $0 $0 Middletown 2,281 1,289 $201,117,200 $273,845,029 $243,010,056 $717,972,285 Total Nice Agricultural 4 3 $565,573 $54,701 $54,701 $674,975 Commercial 375 129 $18,531,349 $34,642,650 $34,642,650 $87,816,649 Industrial 3 2 $399,318 $526,924 $790,386 $1,716,628 Open Space / 28 3 $1,098,931 $1,241,104 $1,241,104 $3,581,139 Rural Lands Residential 3,689 1,140 $61,012,405 $76,455,007 $38,227,504 $175,694,916 Unknown 0 0 $0 $0 $0 $0 Nice Total 4,099 1,277 $81,607,576 $112,920,386 $74,956,345 $269,484,307 Upper Lake Agricultural 518 268 $35,190,569 $24,516,502 $24,516,502 $84,223,573 Commercial 79 62 $7,628,964 $12,654,200 $12,654,200 $32,937,364 Industrial 2 2 $527,848 $418,265 $627,398 $1,573,511 Open Space / 684 163 $31,561,613 $17,126,052 $17,126,052 $65,813,717 Rural Lands Residential 828 579 $37,710,109 $51,316,151 $25,658,076 $114,684,336 Unknown 0 0 $0 $0 $0 $0 Upper Lake 2,111 1,074 $112,619,103 $106,031,170 $80,582,227 $299,232,500 Total Whispering Pines Agricultural 4 0 $46,409 $0 $0 $46,409 Commercial 10 6 $262,284 $520,764 $520,764 $1,303,812

Lake County Public Review Draft 4-155 Local Hazard Mitigation Plan Update January 2018 Unincorporated Total Parcel Improved Total Land Improved Estimated Total Value Communities / Count Parcel Count Value Structure Contents Property Use Value Value Industrial 0 0 $0 $0 $0 $0 Open Space / 45 16 $4,367,310 $1,275,455 $1,275,455 $6,918,220 Rural Lands Residential 290 132 $5,052,767 $5,491,037 $2,745,519 $13,289,323 Unknown 0 0 $0 $0 $0 $0 Whispering 349 154 $9,728,770 $7,287,256 $4,541,738 $21,557,764 Pines Total Witter Springs Agricultural 77 50 $6,753,312 $6,631,203 $6,631,203 $20,015,718 Commercial 0 0 $0 $0 $0 $0 Industrial 0 0 $0 $0 $0 $0 Open Space / 73 34 $6,556,494 $5,064,937 $5,064,937 $16,686,368 Rural Lands Residential 29 23 $2,599,484 $2,179,760 $1,089,880 $5,869,124 Unknown 0 0 $0 $0 $0 $0 Witter Springs 179 107 $15,909,290 $13,875,900 $12,786,020 $42,571,210 Total

Lake County 47,206 22,900 $2,044,169,239 $2,956,943,629 $1,902,024,818 $6,903,137,686 Total Source: Lake County 1/3/2017 Parcel/Assessor’s Data

Critical Facility Inventory

TO BE INSERTED WHEN COMPLETED

Cultural, Historical, and Natural Resources

Assessing Lake County’s vulnerability to disaster also involves inventorying the cultural, historical, and natural resource assets of the area. This information is important for the following reasons:

➢ The community may decide that these types of resources warrant a greater degree of protection due to their unique and irreplaceable nature and contribution to the overall economy. ➢ In the event of a disaster, an accurate inventory of cultural, historical and natural resources allows for more prudent care in the disaster’s immediate aftermath when the potential for additional impacts is higher. ➢ The rules for reconstruction, restoration, rehabilitation, and/or replacement are often different for these types of designated resources. ➢ Natural resources can have beneficial functions that reduce the impacts of natural hazards, for example, wetlands and riparian and sensitive habitat which help absorb and attenuate floodwaters and thus support overall mitigation objectives.

Lake County Public Review Draft 4-156 Local Hazard Mitigation Plan Update January 2018 Cultural and Historical Resources

Lake County has a large stock of historically significant homes, public buildings, and landmarks. To inventory these resources, the HMPC collected information from a number of sources. The California Department of Parks and Recreation Office of Historic Preservation (OHP) was the primary source of information. The OHP is responsible for the administration of federally and state mandated historic preservation programs to further the identification, evaluation, registration, and protection of California’s irreplaceable archaeological and historical resources. OHP administers the National Register of Historic Places, the California Register of Historical Resources, California Historical Landmarks, and the California Points of Historical Interest programs. Each program has different eligibility criteria and procedural requirements.

➢ The National Register of Historic Places is the nation’s official list of cultural resources worthy of preservation. The National Register is part of a national program to coordinate and support public and private efforts to identify, evaluate, and protect historic and archeological resources. Properties listed include districts, sites, buildings, structures, and objects that are significant in American history, architecture, archeology, engineering, and culture. The National Register is administered by the National Park Service, which is part of the U.S. Department of the Interior. ➢ The California Register of Historical Resources program encourages public recognition and protection of resources of architectural, historical, archeological, and cultural significance and identifies historical resources for state and local planning purposes; determines eligibility for state historic preservation grant funding; and affords certain protections under the California Environmental Quality Act. The Register is the authoritative guide to the state’s significant historical and archeological resources. ➢ California Historical Landmarks are sites, buildings, features, or events that are of statewide significance and have anthropological, cultural, military, political, architectural, economic, scientific or technical, religious, experimental, or other value. Landmarks #770 and above are automatically listed in the California Register of Historical Resources. ➢ California Points of Historical Interest are sites, buildings, features, or events that are of local (city or county) significance and have anthropological, cultural, military, political, architectural, economic, scientific or technical, religious, experimental, or other value. Points designated after December 1997 and recommended by the State Historical Resources Commission are also listed in the California Register.

Historical resources included in the programs above are identified in Table 4-42.

Table 4-42 Lake County Historical Resources

National State Point of Resource Name (Plaque Number) Register Landmark Interest Date Listed City Anderson Marsh Archeological District (N656) X 8/24/1978 Lower Lake Archeological Site No. Ca-Lak-711 (N780) X 5/25/1979 Anderson Springs Battle Of Bloody Island (427) X 3/16/1949 Upper Lake Borax Lake--Hodges Archeological Site (N1738) X 10/3/1991 Clearlake

Lake County Public Review Draft 4-157 Local Hazard Mitigation Plan Update January 2018 National State Point of Resource Name (Plaque Number) Register Landmark Interest Date Listed City Cache Creek Archeological District (N2001) X 12/30/1997 Lower Lake Cobb Valley School (P496) X 1/13/1977 Cobb Cobblestone Building (P714) X 6/12/1989 Clearlake Community Methodist Church (P62) X 9/22/1967 Middletown Great Western Quicksilver Mine (P60) X 9/22/1967 Middletown Konocti Harbor (P449) X 12/22/1975 Clearlake Lake County Courthouse (N59) X 10/28/1970 Lakeport Lake County House/Middletown Hotel/Herrick X 5/15/1996 Middletown House/Berry Ho (P820) Lakeport Carnegie Library (N2406) X 4/10/2008 Lakeport Lower Lake Historic Schoolhouse (P772) X 8/21/1992 Lower Lake Lower Lake Schoolhouse, Konocti Grange Hall X 9/22/1967 Lower Lake (P61) Lower Lake Stone Jail (429) X 3/16/1949 Lower Lake Old Lake County Courthouse (897) X 6/16/1976 Lakeport Patwin Indian Site (N152) X 2/23/1972 Clearlake Oaks Site of Stone and Kelsey Home (426) X 3/16/1949 Kelseyville St. Helena Toll Road and Bull Trail (467) X 8/30/1950 Middletown St. John's Episcopal Church (P679) X 11/28/1986 Lakeport Stone House (450) X 11/2/1949 Middletown Sulphur Bank Mine (428) X 3/16/1949 Clearlake Oaks Source: California Department of Parks and Recreation Office of Historic Preservation, http://ohp.parks.ca.gov/

It should be noted that these lists may not be complete, as they may not include those currently in the nomination process and not yet listed. Additionally, as defined by the California Environmental Quality Act (CEQA) and the National Environmental Policy Act (NEPA), any property over 50 years of age is considered a historic resource and is potentially eligible for the National Register. Thus, in the event that the property is to be altered, or has been altered, as the result of a major federal action, the property must be evaluated under the guidelines set forth by CEQA and NEPA. Structural mitigation projects are considered alterations for the purpose of this regulation.

Natural Resources

Natural resources are important to include in cost/benefit analyses for future projects and may be used to leverage additional funding for mitigation projects that also contribute to community goals for protecting sensitive natural resources. Awareness of natural assets can lead to opportunities for meeting multiple objectives. For instance, protecting wetlands areas protects sensitive habitat as well as reducing the force of and storing floodwaters. The County has mapped natural areas that exist in the County. These are shown on Figure 4-54.

Lake County Public Review Draft 4-158 Local Hazard Mitigation Plan Update January 2018 Figure 4-54 Lake County – Natural Areas

Source: 2008 Lake County General Plan

Lake County Public Review Draft 4-159 Local Hazard Mitigation Plan Update January 2018 Lake County has over 10,000 acres of parks, public lands, and 500 square miles of waterways that are managed by various government entities, including the cities, county, state and federal governments (i.e., Bureau of Land Management, U.S. Forest Service) and non-profit organizations (i.e., The Nature Conservancy). These areas can be seen on Figure 4-55.

Lake County Public Review Draft 4-160 Local Hazard Mitigation Plan Update January 2018 Figure 4-55 Lake County – Parks and Recreation Areas

Source: 2008 Lake County General Plan Lake County Public Review Draft 4-161 Local Hazard Mitigation Plan Update January 2018 Special Status Species

To further understand natural resources that may be particularly vulnerable to a hazard event, as well as those that need consideration when implementing mitigation activities, it is important to identify at-risk species (i.e., endangered species) in the Planning Area. An endangered species is any species of fish, plant life, or wildlife that is in danger of extinction throughout all or most of its range. A threatened species is a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Both endangered and threatened species are protected by law and any future hazard mitigation projects are subject to these laws. Candidate species are plants and animals that have been proposed as endangered or threatened but are not currently listed.

The California Natural Diversity Database, a program that inventories the status and locations of rare plants and animals in California, was queried to create an inventory of special status species in Lake County. Table 4-43 lists the name, federal status, state status, California Department of Fish and Wildlife status, and the California Rare Plant rank of species in Lake County.

Table 4-43 Special Status Species in Lake County

Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Animals – Amphibians Ambystoma californiense California tiger salamander Threatened Threatened WL – Dicamptodon ensatus California giant salamander None None SSC – Rana boylii foothill yellow-legged frog None Candidate SSC – Threatened Rana draytonii California red-legged frog Threatened None SSC – Taricha rivularis red-bellied newt None None SSC – Animals – Birds Accipiter gentilis northern goshawk None None SSC – Aquila chrysaetos golden eagle None None FP, WL – Circus cyaneus northern harrier None None SSC – Elanus leucurus white-tailed kite None None FP – Haliaeetus leucocephalus bald eagle Delisted Endangered FP – Pandion haliaetus osprey None None WL – Branta hutchinsii leucopareia cackling (=Aleutian Canada) Delisted None – – goose Ardea alba great egret None None – – Ardea herodias great blue heron None None – – Egretta thula snowy egret None None – – Nycticorax nycticorax black-crowned night heron None None – – Coccyzus americanus occidentalis western yellow-billed cuckoo Threatened Endangered – – Artemisiospiza belli belli Bell's sage sparrow None None WL –

Lake County Public Review Draft 4-162 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Falco mexicanus prairie falcon None None WL – Falco peregrinus anatum American peregrine falcon Delisted Delisted FP – Progne subis purple martin None None SSC – Agelaius tricolor tricolored blackbird None Candidate SSC – Endangered Baeolophus inornatus oak titmouse None None – – Pelecanus erythrorhynchos American white pelican None None SSC – Phalacrocorax auritus double-crested cormorant None None WL – Athene cunicularia burrowing owl None None SSC – Strix occidentalis caurina northern spotted owl Threatened Threatened SSC – Animals – Crustaceans Calasellus californicus An isopod None None – – Linderiella occidentalis California linderiella None None – Animals – Fish Archoplites interruptus Sacramento perch None None SSC – Lavinia exilicauda chi Clear Lake hitch None Threatened – – Hysterocarpus traski pomo Russian River tule perch None None SSC – Oncorhynchus mykiss irideus steelhead - northern California Threatened None – – DPS Animals – Insects Andrena blennospermatis Blennosperma vernal pool None None – – andrenid bee Bombus caliginosus obscure bumble bee None None – – Bombus occidentalis western bumble bee None None – – Trachykele hartmani serpentine cypress wood- None None – – boring beetle Hedychridium milleri Borax Lake cuckoo wasp None None – – Dubiraphia brunnescens brownish dubiraphian riffle None None – – beetle Hydrochara rickseckeri Ricksecker's water scavenger None None – – beetle Saldula usingeri Wilbur Springs shorebug None None – – Animals – Mammals Erethizon dorsatum North American porcupine None None – – Perognathus inornatus San Joaquin Pocket Mouse None None – – Gulo gulo California wolverine Proposed Threatened FP – Threatened Martes caurina humboldtensis Humboldt marten None Candidate SSC – Endangered

Lake County Public Review Draft 4-163 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Pekania pennanti fisher - West Coast DPS Proposed Candidate SSC – Threatened Threatened Taxidea taxus American badger None None SSC – Antrozous pallidus pallid bat None None SSC – Corynorhinus townsendii Townsend's big-eared bat None None SSC – Lasionycteris noctivagans silver-haired bat None None – – Lasiurus blossevillii western red bat None None SSC – Lasiurus cinereus hoary bat None None – – Myotis evotis long-eared myotis None None – – Myotis lucifugus little brown bat None None – – Myotis thysanodes fringed myotis None None – – Myotis yumanensis Yuma myotis None None – – Animals – Mollusks Pyrgulopsis ventricosa Clear Lake pyrg None None – – Margaritifera falcata western pearlshell None None – – Anodonta oregonensis Oregon floater None None – – Gonidea angulata western ridged mussel None None – – Animals – Reptiles Emys marmorata western pond turtle None None SSC – Sceloporus graciosus graciosus northern sagebrush lizard None None – – Community – Aquatic – Central Valley Drainage None None – – Rainbow Trout/Cyprinid Stream – Clear Lake Drainage None None – – Cyprinid/Catostomid Stream – Clear Lake Drainage Resident None None – – Trout Stream – Clear Lake Drainage Seasonal None None – – Lakefish Spawning Stream Community – Terrestrial – Coastal and Valley Freshwater Coastal and None – – Marsh Valley Freshwater Marsh – Great Valley Mixed Riparian Great Valley None – – Forest Mixed Riparian Forest

Lake County Public Review Draft 4-164 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank – Northern Basalt Flow Vernal Northern None – – Pool Basalt Flow Vernal Pool – Northern Interior Cypress Northern None – – Forest Interior Cypress Forest – Northern Vernal Pool Northern None – – Vernal Pool – Northern Volcanic Ash Vernal Northern None – – Pool Volcanic Ash Vernal Pool – Serpentine Bunchgrass Serpentine None – – Bunchgrass Plants – Bryophytes Plagiobryoides vinosula wine-colored tufa moss None None – 4.2 Trichodon cylindricus cylindrical trichodon None None – 2B.2 Grimmia torenii Toren's grimmia None None – 1B.3 Mielichhoferia elongata elongate copper moss None None – 4.3 Didymodon californicus California beard-moss None None – 4.2 Tortella alpicola alpine crisp-moss None None – 2B.3 Plants – Vascular Chlorogalum pomeridianum var. dwarf soaproot None None – 1B.2 minus Allium fimbriatum var. purdyi Purdy's onion None None – 4.3 Eryngium constancei Loch Lomond button-celery Endangered Endangered – 1B.1 Lomatium hooveri Hoover's lomatium None None – 4.3 Lomatium repostum Napa lomatium None None – 4.3 Asclepias solanoana serpentine milkweed None None – 4.2 Anisocarpus scabridus scabrid alpine tarplant None None – 1B.3 Balsamorhiza macrolepis big-scale balsamroot None None – 1B.2 Calycadenia micrantha small-flowered calycadenia None None – 1B.2 Centromadia parryi ssp. parryi pappose tarplant None None – 1B.2 Centromadia parryi ssp. rudis Parry's rough tarplant None None – 4.2 Erigeron greenei Greene's narrow-leaved daisy None None – 1B.2 Harmonia hallii Hall's harmonia None None – 1B.2 Harmonia nutans nodding harmonia None None – 4.3 Harmonia stebbinsii Stebbins' harmonia None None – 1B.2 Helianthus exilis serpentine sunflower None None – 4.2

Lake County Public Review Draft 4-165 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Hemizonia congesta ssp. Mendocino tarplant None None – 4.3 calyculata Lasthenia burkei Burke's goldfields Endangered Endangered – 1B.1 Layia septentrionalis Colusa layia None None – 1B.2 Micropus amphibolus Mt. Diablo cottonweed None None – 3.2 Tracyina rostrata beaked tracyina None None – 1B.2 Azolla microphylla Mexican mosquito fern None None – 4.2 Amsinckia lunaris bent-flowered fiddleneck None None – 1B.2 Cryptantha dissita serpentine cryptantha None None – 1B.2 Hackelia amethystina amethyst stickseed None None – 4.3 Plagiobothrys lithocaryus Mayacamas popcornflower None None – 1A Arabis blepharophylla coast rockcress None None – 4.3 Arabis modesta modest rockcress None None – 4.3 Boechera ultraalsa Snow Mountain rockcress None None – 1B.1 Streptanthus barbiger bearded jewelflower None None – 4.2 Streptanthus brachiatus ssp. Socrates Mine jewelflower None None – 1B.2 brachiatus Streptanthus brachiatus ssp. Freed's jewelflower None None – 1B.2 hoffmanii Streptanthus glandulosus ssp. Hoffman's bristly jewelflower None None – 1B.3 hoffmanii Streptanthus hesperidis green jewelflower None None – 1B.2 Streptanthus morrisonii ssp. Three Peaks jewelflower None None – 1B.2 elatus Streptanthus morrisonii ssp. Kruckeberg's jewelflower None None – 1B.2 kruckebergii Streptanthus vernalis early jewelflower None None – 1B.2 Brasenia schreberi watershield None None – 2B.3 Legenere limosa legenere None None – 1B.1 Viburnum ellipticum oval-leaved viburnum None None – 2B.3 Calystegia collina ssp. oxyphylla Mt. Saint Helena morning- None None – 4.2 glory Calystegia collina ssp. tridactylosa three-fingered morning-glory None None – 1B.2 Calystegia collina ssp. venusta South Coast Range morning- None None – 4.3 glory Calystegia purpurata ssp. coastal bluff morning-glory None None – 1B.2 saxicola Cuscuta jepsonii Jepson's dodder None None – 1B.2 Sedella leiocarpa Lake County stonecrop Endangered Endangered – 1B.1

Lake County Public Review Draft 4-166 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Carex comosa bristly sedge None None – 2B.1 Carex hystericina porcupine sedge None None – 2B.1 Carex klamathensis Klamath sedge None None – 1B.2 Carex praticola northern meadow sedge None None – 2B.2 Arctostaphylos manzanita ssp. Konocti manzanita None None – 1B.3 elegans Arctostaphylos stanfordiana ssp. Raiche's manzanita None None – 1B.1 raichei Amorpha californica var. Napa false indigo None None – 1B.2 napensis Astragalus breweri Brewer's milk-vetch None None – 4.2 Astragalus clevelandii Cleveland's milk-vetch None None – 4.3 Astragalus rattanii var. Jepson's milk-vetch None None – 1B.2 jepsonianus Lupinus antoninus Anthony Peak lupine None None – 1B.3 Lupinus sericatus Cobb Mountain lupine None None – 1B.2 Trifolium hydrophilum saline clover None None – 1B.2 California macrophylla round-leaved filaree None None – 1B.2 Juglans hindsii Northern California black None None – 1B.1 walnut Monardella viridis green monardella None None – 4.3 Trichostema ruygtii Napa bluecurls None None – 1B.2 Calochortus uniflorus pink star-tulip None None – 4.2 Erythronium helenae St. Helena fawn lily None None – 4.2 Fritillaria glauca Siskiyou fritillaria None None – 4.2 Fritillaria pluriflora adobe-lily None None – 1B.2 Fritillaria purdyi Purdy's fritillary None None – 4.3 Limnanthes floccosa ssp. floccosa woolly meadowfoam None None – 4.2 Hesperolinon adenophyllum glandular western flax None None – 1B.2 Hesperolinon bicarpellatum two-carpellate western flax None None – 1B.2 Hesperolinon didymocarpum Lake County western flax None Endangered – 1B.2 Hesperolinon drymarioides drymaria-like western flax None None – 1B.2 Hesperolinon sharsmithiae Sharsmith's western flax None None – 1B.2 Iliamna bakeri Baker's globe mallow None None – 4.2 Malacothamnus helleri Heller's bush-mallow None None – 3.3 Sidalcea hickmanii ssp. Lake Pillsbury checkerbloom None None – 1B.2 pillsburiensis Sidalcea oregana ssp. hydrophila marsh checkerbloom None None – 1B.2

Lake County Public Review Draft 4-167 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Toxicoscordion fontanum marsh zigadenus None None – 4.2 Calyptridium quadripetalum four-petaled pussypaws None None – 4.3 Lewisia stebbinsii Stebbins' lewisia None None – 1B.2 Clarkia gracilis ssp. tracyi Tracy's clarkia None None – 4.2 Epilobium nivium Snow Mountain willowherb None None – 1B.2 Piperia leptopetala narrow-petaled rein orchid None None – 4.3 Piperia michaelii Michael's rein orchid None None – 4.2 Castilleja rubicundula var. pink creamsacs None None – 1B.2 rubicundula Cordylanthus tenuis ssp. serpentine bird's-beak None None – 4.3 brunneus Orobanche valida ssp. howellii Howell's broomrape None None – 4.3 Erythranthe nudata bare monkeyflower None None – 4.3 Antirrhinum subcordatum dimorphic snapdragon None None – 4.3 Antirrhinum virga twig-like snapdragon None None – 4.3 Gratiola heterosepala Boggs Lake hedge-hyssop None Endangered – 1B.2 Penstemon newberryi var. Sonoma beardtongue None None – 1B.3 sonomensis Calamagrostis ophitidis serpentine reed grass None None – 4.3 Imperata brevifolia California satintail None None – 2B.1 Orcuttia tenuis slender Orcutt grass Threatened Endangered – 1B.1 Puccinellia simplex California alkali grass None None – 1B.2 Stipa lemmonii var. pubescens pubescent needle grass None None – 3.2 Collomia diversifolia serpentine collomia None None – 4.3 Eriastrum brandegeeae Brandegee's eriastrum None None – 1B.1 Eriastrum tracyi Tracy's eriastrum None Rare – 3.2 Leptosiphon acicularis bristly leptosiphon None None – 4.2 Leptosiphon jepsonii Jepson's leptosiphon None None – 1B.2 Navarretia cotulifolia cotula navarretia None None – 4.2 Navarretia jepsonii Jepson's navarretia None None – 4.3 Navarretia leucocephala ssp. Baker's navarretia None None – 1B.1 bakeri Navarretia leucocephala ssp. few-flowered navarretia Endangered Threatened – 1B.1 pauciflora Navarretia leucocephala ssp. many-flowered navarretia Endangered Endangered – 1B.2 plieantha Navarretia myersii ssp. deminuta small pincushion navarretia None None – 1B.1 Navarretia paradoxinota Porter's navarretia None None – 1B.3

Lake County Public Review Draft 4-168 Local Hazard Mitigation Plan Update January 2018 Scientific Name Common Name Federal Status State Status CDFW CA Rare Status Plant Rank Eriogonum nervulosum Snow Mountain buckwheat None None – 1B.2 Eriogonum tripodum tripod buckwheat None None – 4.2 Potamogeton zosteriformis eel-grass pondweed None None – 2B.2 Delphinium uliginosum swamp larkspur None None – 4.2 Myosurus minimus ssp. apus little mousetail None None – 3.1 Ranunculus lobbii Lobb's aquatic buttercup None None – 4.2 Ceanothus confusus Rincon Ridge ceanothus None None – 1B.1 Ceanothus divergens Calistoga ceanothus None None – 1B.2 Ceanothus sonomensis Sonoma ceanothus None None – 1B.2 Horkelia bolanderi Bolander's horkelia None None – 1B.2 Brodiaea leptandra narrow-anthered brodiaea None None – 1B.2 Brodiaea rosea Indian Valley brodiaea None Endangered – 1B.1 Sources: California Natural Diversity Database BIOS Viewer Tool Federal Status Endangered: The classification provided to an animal or plant in danger of extinction within the foreseeable future throughout all or a significant portion of its range. Threatened: The classification provided to an animal or plant which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Proposed Endangered: The classification provided to an animal or plant that is proposed for federal listing as Endangered in the Federal Register under Section 4 of the Endangered Species Act. Proposed Threatened: The classification provided to an animal or plant that is proposed for federal listing as Threatened in the Federal Register under Section 4 of the Endangered Species Act. Candidate: The classification provided to an animal or plant that has been studied by the United States Fish and Wildlife Service, and the Service has concluded that it should be proposed for addition to the Federal Endangered and Threatened species list. None: The plant or animal has no federal status. Delisted: The plant or animal was previously listed as Endangered or Threatened, but is no longer listed on the Federal Endangered and Threatened species list. CDFW Status FP: Fully Protected: This classification was the State of California's initial effort to identify and provide additional protection to those animals that were rare or faced possible extinction. SSC: Species of Special Concern: To this end, the Department has designated certain vertebrate species as "Species of Special Concern" because declining population levels, limited ranges, and/or continuing threats have made them vulnerable to extinction. The goal of designating species as "Species of Special Concern" is to halt or reverse their decline by calling attention to their plight and addressing the issues of concern early enough to secure their long-term viability. WL: Watch List: Species that were previously designated as "Species of Special Concern" but no longer merit that status, or which do not yet meet SSC criteria, but for which there is concern and a need for additional information to clarify status. CA Rare Plant Rank 1A: Plants presumed extinct in California and rare/extinct elsewhere 1B.1: Plants rare, threatened, or endangered in California and elsewhere; seriously threatened in California 1B.2: Plants rare, threatened, or endangered in California and elsewhere; fairly threatened in California 1B.3: Plants rare, threatened, or endangered in California and elsewhere; not very threatened in California 2A: Plants presumed extirpated in California, but more common elsewhere 2B.1: Plants rare, threatened, or endangered in California, but more common elsewhere; seriously threatened in California 2B.2: Plants rare, threatened, or endangered in California, but more common elsewhere; fairly threatened in California 2B.3: Plants rare, threatened, or endangered in California, but more common elsewhere; not very threatened in California 3.1: Plants about which we need more information; seriously threatened in California 3.2: Plants about which we need more information; fairly threatened in California

Lake County Public Review Draft 4-169 Local Hazard Mitigation Plan Update January 2018 3.3: Plants about which we need more information; not very threatened in California 4.1: Plants of limited distribution; seriously threatened in California 4.2: Plants of limited distribution; fairly threatened in California 4.3: Plants of limited distribution; not very threatened in California

Wetlands

Wetlands are habitats in which soils are intermittently or permanently saturated or inundated. Wetland habitats vary from rivers to seasonal ponding of alkaline flats and include swamps, bogs, marshes, vernal pools, and riparian woodlands. Wetlands are considered to be waters of the United States and are subject to the jurisdiction of the U.S. Army Corps of Engineers as well as the California Department of Fish and Wildlife (CDFW). Where the waters provide habitat for federally endangered species, the U.S. Fish and Wildlife Service may also have authority.

Wetlands are a valuable natural resource for communities providing beneficial impact to water quality, wildlife protection, recreation, and education, and play an important role in hazard mitigation. Wetlands provide drought relief in water-scarce areas where the relationship between water storage and streamflow regulation is vital, and reduce flood peaks and slowly release floodwaters to downstream areas. When surface runoff is dampened, the erosive powers of the water are greatly diminished. Furthermore, the reduction in the velocity of inflowing water as it passes through a wetland helps remove sediment being transported by the water.

Wetlands in Lake County are generally small, isolated features dependent on riparian water, ditch leaks or overflows, diversions by agricultural operations or natural seeps or springs. Man-made or naturally occurring wetlands provide an important biological resource both through provision of localized habitat and habitat for migratory species and as a natural water filtration system. The primary issues related to wetlands are loss due to filling as a result of land development; degradation or loss due to interruption of water supply from natural and man-made drainage systems; and degradation due to degraded water quality, resulting from increased pollution from urban runoff, sedimentation, pesticides and herbicides. Wetlands in the County are shown in Figure 4-56.

Lake County Public Review Draft 4-170 Local Hazard Mitigation Plan Update January 2018 Figure 4-56 Lake County – Wetlands

Lake County Public Review Draft 4-171 Local Hazard Mitigation Plan Update January 2018 Natural and Beneficial Functions

Wetlands are often found in floodplains and depressional areas of a watershed. Many wetlands receive and store floodwaters, thus slowing and reducing downstream flow. Wetlands perform a variety of ecosystem functions including food web support, habitat for insects and other invertebrates, fish and wildlife habitat, filtering of waterborne and dry-deposited anthropogenic pollutants, carbon storage, water flow regulation (e.g., flood abatement), groundwater recharge, and other human and economic benefits.

Wetlands, and other riparian and sensitive areas, provide habitat for insects and other invertebrates that are critical food sources to a variety of wildlife species, particularly birds. There are species that depend on these areas during all parts of their lifecycle for food, overwintering, and reproductive habitat. Other species use wetlands and riparian areas for one or two specific functions or parts of the lifecycle, most commonly for food resources. In addition, these areas produce substantial plant growth that serves as a food source to herbivores (wild and domesticated) and a secondary food source to carnivores.

Wetlands slow the flow of water through the vegetation and soil, and pollutants are often held in the soil. In addition, because the water is slowed, sediments tend to fall out, thus improving water quality and reducing turbidity downstream.

These natural floodplain functions associated with the natural or relatively undisturbed floodplain that moderates flooding, such as wetland areas, are critical for maintaining water quality, recharging groundwater, reducing erosion, redistributing sand and sediment, and providing fish and wildlife habitat. Preserving and protecting these areas and associated functions are a vital component of sound floodplain management practices for the Lake County Planning Area.

Farmlands

Williamson Act

The Williamson Act, also known as the California Land Conservation Act of 1965, enables local governments to enter into contracts with private landowners for the purpose of restricting specific parcels of land to agricultural or related open space use. When the County enters into a contract with the landowners under the Williamson Act, the landowner agrees to limit the use of the land to agriculture and compatible uses for a period of at least ten years and the County agrees to tax the land at a rate based on the agricultural production of the land rather than its real estate market value. This affects the County’s overall values for assessed taxable lands. The County has designated areas as agricultural preserves within which the county will enter into contracts for the preservation of the land in agriculture. The County has 49,658 acres under Williamson Act Contract as of 2009, the last year that data was reported by the County to the State. Locations can be seen on Figure 4-57.

Lake County Public Review Draft 4-172 Local Hazard Mitigation Plan Update January 2018 Figure 4-57 Lake County – Williamson Act Lands

Source: California Department of Conservation

Lake County Public Review Draft 4-173 Local Hazard Mitigation Plan Update January 2018 State Inventory of Important Farmland

The Farmland Mapping and Monitoring Program was established in 1984 to document the location, quality, and quantity of agricultural lands and conversion of those lands over time. The program provides impartial analysis of agricultural land use changes throughout California. For inventory purposes, several categories were developed to describe the qualities of land in terms of its suitability for agricultural production. The State Department of Conservation utilizes the following classification system:

➢ The Prime Farmland category describes farmland with the best combination of physical and chemical features able to sustain long term agricultural production. This land has the soil quality, growing season, and moisture supply needed to produce sustained high yields. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date. ➢ Farmland of Statewide Importance is farmland similar to Prime Farmland but with minor shortcomings, such as greater slopes or less ability to store soil moisture. Land must have been used for irrigated agricultural production at some time during the four years prior to the mapping date. ➢ Unique Farmland is farmland of lesser quality soils used for the production of the state’s leading agricultural crops. This land is usually irrigated, but may include nonirrigated orchards or vineyards as found in some climatic zones in California. Land must have been cropped at some time during the four years prior to the mapping date. ➢ Farmland of Local Importance is either currently producing crops or has the capability of production. This farmland category is determined by each county’s board of supervisors and a local advisory committee.

The 2014 maps are the most recent versions. These lands are shown in Figure 4-58.

Lake County Public Review Draft 4-174 Local Hazard Mitigation Plan Update January 2018 Figure 4-58 Lake County – Map of Important Farmlands 2014

Source: State of California Department of Conservation

Lake County Public Review Draft 4-175 Local Hazard Mitigation Plan Update January 2018 Growth and Development Trends

As part of the planning process, the HMPC looked at changes in growth and development, both past and future, and examined these changes in the context of hazard-prone areas, and how the changes in growth and development affect loss estimates and vulnerability. Information from the Lake County General Plan Housing Element, the California Department of Finance, and the US Census Bureau form the basis of this discussion.

Current Status and Past Development

The estimated population of Lake County (both incorporated communities and the unincorporated County) for January 1, 2017 was 64,945, representing an eight-fold increase from just over 8,000 people in 1940. Table 4-44 illustrates the pace of population growth in Lake County dating back to 1940. The data on population and housing growth shows that Lake County saw tremendous growth during the late the 20th century. That growth has slowed between 2000 and 2010, and the County has seen small population losses since 2010.

Table 4-44 Lake County Population Growth 1940-2017

Year Population Change Percent Increase 1940 8,069 – – 1950 11,481 3,412 42.2% 1960 13,786 2,395 20.1% 1970 19,548 5,762 41.8% 1980 36,366 16,818 86.0% 1990 50,631 14,265 39.2% 2000 58,309 7,948 15.2% 2010 64,665 6,356 10.9% 2017 64,945 280 0.01% Sources: Lake County Housing Element Background Report, California Department of Finance, US Census Bureau

Special Populations

DOES THE COUNTY HAVE INFORMATION ON OTHER SPECIAL POPULATIONS? MEETINGS DISCUSSED LARGE DISPLACED POPULATIONS FROM FIRE. HOW ABOUT ELDERLY, INFIRM, TRANSIENT POPULATIONS, ETC.

Cal DWR Special Population Mapping

The Department of Water Resources (DWR) has developed a web-based application to assist local agencies and other interested parties in evaluating disadvantaged community (DAC) status throughout the State, using the definition provided by Proposition 84 IRWM Guidelines (2015). The DAC Mapping Tool is an interactive map application that allows users to overlay the following three US Census geographies as separate data layers:

Lake County Public Review Draft 4-176 Local Hazard Mitigation Plan Update January 2018 ➢ Census Place ➢ Census Tract ➢ Census Block Group

Only those census geographies that meet the DAC definition are shown on the map (i.e., only those with an annual median household income (MHI) that is less than 80 percent of the Statewide annual MHI (PRC Section 75005(g)). In addition, those census geographies having an annual MHI that is less than 60 percent of the Statewide annual MHI are shown as "Severely Disadvantaged Communities" (SDAC). The DAC map for Lake County is shown in Figure 4-59.

Figure 4-59 Lake County – Disadvantaged Communities

TO BE INSERTED WHEN SITE IS WORKING Source: Cal DWR

Climate Change and Health Profile Report

The 2017 Climate Change and Health Profile Report noted that there are special populations in the County.

In 2010, the age-adjusted death rate in Lake County was higher than as the state average. Disparities in death rates among race/ethnicity groups highlight how certain populations disproportionately experience health impacts. Within the county, the highest death rate occurred among African-Americans and the lowest death rate occurred among Hispanics/Latinos.

In 2012, nearly 46% of adults (59,511; pooled for Mendocino and Lake Counties) reported one or more chronic health conditions including heart disease, diabetes, asthma, severe mental stress or high blood pressure. In 2012, 17% of adults reported having been diagnosed with asthma. In 2012, approximately 26% of adults were obese (statewide average was 25%). In 2012, nearly 20% of residents aged 5 years and older had a mental or physical disability (statewide average was 10%).

Development since 2011 Plan

The Lake County Building Department and Planning Department tracked total building permits issued since 2011 for unincorporated Lake County. A summary of all development is shown in Table 4-45. These are tracked by hazard area and by property use type, and area shown in Table 4-46. Lake County does track development in wildfire areas; however, the County does not track development in flood or other areas. All development in the wildfire hazard area was completed in accordance with all current and applicable development codes and standards and should be adequately protected. Thus, with the exception of more people living in the area potentially exposed to natural hazards, this growth should not cause a significant change in vulnerability of the Lake County Planning Area to identified priority hazards.

Table 4-45 Lake County Development since 2011 Summary

Property Use 2011 2012 2013 2014 2015 Residential 17 31 56 45 55 Commercial 91 136 99 101 94

Lake County Public Review Draft 4-177 Local Hazard Mitigation Plan Update January 2018 Property Use 2011 2012 2013 2014 2015 Industrial 1 4 10 3 3 Other 218 235 248 207 217 Total 327 406 413 356 369 Source: Lake County Building Department

Table 4-46 Lake County Development in Hazard Zones since 2011

Property Use 1 % Annual Chance Flood Wildfire Very High Other Residential – 84 – Commercial – 16 – Industrial – – – Other – – – Total – 100 – Source: Lake County Building Department

Future Development

As indicated in the previous section, Lake County had been steadily growing from 1940 to 2010, with a recent slowing in population growth. Long term forecasts by the California Department of Finance project population growth in Lake County continuing through the 2060. Table 4-47 shows the population projections for the County as a whole through 2060.

Table 4-47 Population Projections for Lake County (incorporated and unincorporated), 2020- 2060

2020 2025 2030 2035 2040 2045 2050 2055 2060 Lake 65,484 66,476 67,718 69,030 70,275 71,574 73,015 74,769 76,877 Source: California Department of Finance, P-1 Report

Land Use

The future use of land in the County is fundamental to attaining the vision of a balanced, self-sustaining community. A land use pattern which balances growth between rural and urban areas, as well as providing a balance between housing, employment, natural resources, and services in the County is a key element in maintaining the quality of life and unique character of the County. Descriptions of allowed uses for each classification are detailed in the 2008 Lake County General Plan Land Use Element. Figure 4-60 is sourced from this section.

Lake County Public Review Draft 4-178 Local Hazard Mitigation Plan Update January 2018 Figure 4-60 Lake County General Plan Land Use

Source: 2008 Lake County General Plan Land Use Element

Lake County Public Review Draft 4-179 Local Hazard Mitigation Plan Update January 2018 Future Development Area Analysis

Lake County has designated certain areas where future growth is being targeted and considered. The Land Use Diagram (shown on the previous page) designates land uses for the entire Planning Area. State planning law requires that the general plan cover all territory within the boundaries of the adopting city or county as well as “any land outside its boundary which in the planning agency’s judgment bears relation to its planning” (Government Code Section 65300). To carry out this directive, most counties formally delineate a “planning area” boundary in their general plans. For the purposes of the Lake County General Plan, the Planning Area has been defined as the entire unincorporated area of the county. With the countywide planning area, there are eight community plan areas including: Cobb Mountain, Kelseyville, Lakeport, Lower Lake, Middletown, Rivieras, Shoreline Communities, and Upper Lake‐Nice. These eight areas area shown on Table 4-48. Future development i