The Federal Emergency Management Agency (FEMA) creates and provides authoritative data related to flood insurance. Using that data, the Los Angeles County Department of Public Works has developed a public-facing web viewer for accessing flood zone information in the County of Los Angeles (Flood Zone Determination Website). Flood Zones are represented by letters for special flood hazard areas by FEMA. For example, Zone A areas have a 1 percent annual chance of flooding. This flood is also called the 100-year flood. Property owners with structures in Flood Zone A, which have a federally backed mortgage are required to obtain flood insurance.

Looking for more than just a current flood map? Visit Search All Products to access the FEMA website and obtain a full range of flood risk products for your community.

Purpose:

To provide flood zone information to the public.

Supplemental Information:

Data from Flood Insurance Rate Maps (FIRMs), where available digitally, can be found on the official FEMA’s National Flood Hazard Layer. The DFIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper Flood Insurance Rate Maps (FIRMs) FEMA Flood Maps can be obtained from the FEMA Flood Map Service Center (MSC) The National Flood Hazard Layer (NFHL) is a digital database that contains flood hazard mapping data from FEMAs National Flood Insurance Program (NFIP). This map data is derived from Flood Insurance Rate Map (FIRM) databases and Letters of Map Revision (LOMRs). The NFHL is for community officials and members looking to view effective regulatory flood hazard information in a Geographic Information Systems (GIS) application.

FEMA has additional information on the National Flood Insurance Program and Flood Hazard Mapping.

The Los Angeles County Flood Control District (District) was established in 1915 and encompasses approximately 2,758 square miles. The District operates and maintains one of the most complex systems of flood control and water conservation in the Country. The District’s current infrastructure includes 14 major dams and reservoirs, 483 miles of concrete and soft-bottom channels, 3,380 miles of underground storm drain conduits, 82,275 catch basins, 48 pump stations, 173 debris basins, 181 crib dams, 29 sediment placement sites, 27 spreading grounds, 21 low-flow diversion structures, 3 seawater barrier systems with 290 seawater barrier injection wells, 1 constructed wetland, and 1 mitigation bank area. Employees of the Los Angeles County Public Works (PW) serve as staff for the District. The District is separate from PW and funds of each entity remain in separate accounts. PW pays the District for the use of District equipment, materials and property used for County purposes. The District is empowered to carry out the objectives of the Los Angeles County Flood Control Act of 1915, California Water Code, Appendix, Chapter 28 (the Act). The objectives are to provide for the control and conservation of flood, storm and other wastewater and to protect from damage such as flood or storm waters, the harbors, waterways, public highways and property within the District. These powers are exercised by the County Board of Supervisors (Board), which acts as the governing body of the District. The duties of the Board include approving the District’s budget, determining the District’s tax rates, approving contracts, and determining when to issue bonds authorized by the voters of the District.

This dataset seeks to encapsulate right of way parcel information for the Los Angeles County Flood Control District(LACFCD). It contains polygons representing each parcel and attribute information information that lists the basic identification information of those parcels. There is also information on the underlying right-of-way map that the parcel polygon and attributes are based on--with a link to that map in the Land Records Information Website.This data is maintained by the Right of Way Section of the Survey/Mapping and Property Management Division of the Department of Public Works. It is drawn to be coincident with the county's landbase linework and thus may not be a true representation of a parcel's boundary. It is intended to be used as a general information tool and is not survey quality.Field ListFacilityThe primary name of the facility this parcel belongs to. Typically the name of the river, stream, or drainage project it is a part of.Parcel_NoThe identification number for a particular parcel within a facility. The parcel number is not necessarilly unique.EstateThe type of estate that the LACFCD holds over a particular parcel. This field will list the following attributes:Fee: The LACFCD owns the parcel outright.Easement: The LACFCD holds an easement over this parcel. The type of easement is not listed in this data. It can usually be found in the linked right of way map or by contacting Right of Way Engineering.Quitclaim: This is a parcel which the LACFCD owned or had an easement over at some point but has now sold, released its claim, or transferred its right of way to another party.Other: This is a catch-all attribute for any sort of relationship that does not fit in the other estate types. One example of this is a permit that grants temporary rights to the LACFCD. Map_NoThe primary right of way map that shows a parcel and that served as the basis for the information shown in the dataset. These maps are maintained and are considered to take precedence over the data in this dataset.MapLinkThis is a link to a a scan of the map, if one exists, listed in the "Map_No" field. These are color scans found in the LA County's Land Records Information Website. Update Schedule: QuarterlyContact Info:Diego Veradvera@dpw.lacounty.gov(626) 458-7368Right of Way SectionSurvey/Mapping and Property Management DivisionDepartment of Public Works

The Los Angeles County Storm Drain System shows drains, channels, catch basins, and debris basins in the County of Los Angeles using a web-based map viewer. It currently includes facilities owned and maintained by the Los Angeles County Flood Control District (District), the City of Los Angeles, and United States Army Corps of Engineers (Corps). Information on the facilities, such as date built, size, and material can be obtained by selecting them. The plans are also available for the Corps and District facilities.

The Los Angeles County Flood Control District is managed by the Los Angeles County Department of Public Works.

This dataset seeks to encapsulate right of way parcel information for the Los Angeles County Flood Control District(LACFCD). It contains polygons representing each parcel and attribute information information that lists the basic identification information of those parcels. There is also information on the underlying right-of-way map the parcel polygon and attributes are based on with a link to that map in the Land Records Information Website.This data is maintained by the Right of Way Section of the Survey/Mapping and Property Management Division of the Department of Public Works. It is drawn to be coincident with the county's landbase linework and thus may not be a true representation of a parcel's boundary. It is intended to be used as a general information tool and is emphatically not survey quality.Field ListFacilityThe primary name of the facility this parcel belongs to. Typically the name of the river, stream, or drainage project it is a part of.Parcel_NoThe identification number for a particular parcel within a facility. The parcel number is not necessarilly unique.EstateThe type of estate that the LACFCD holds over a particular parcel. This field will list the following attributes:Fee: The LACFCD owns the parcel outright.Easement: The LACFCD holds an easement over this parcel. The type of easement is not listed in this data. It can usually be found in the linked right of way map or by contacting Right of Way Engineering.Quitclaim: This is a parcel which the LACFCD owned or had an easement over at some point but has now sold, released its claim, or transferred its right of way to another party.Other: This is a catch-all attribute for any sort of relationship that does not fit in the other estate types. One example of this is a permit that grants temporary rights to the LACFCD. Map_NoThe primary right of way map that shows a parcel and that served as the basis for the information shown in the dataset. These maps are maintained and are considered to take precedence over the data in this dataset.MapLinkThis is a link to a a scan of the map, if one exists, listed in the "Map_No" field. These are color scans found in the LA County's Land Records Information Website. Update Schedule: QuarterlyContact Info:Diego Veradvera@dpw.lacounty.gov(626) 458-7368Right of Way SectionSurvey/Mapping and Property Management DivisionDepartment of Public Works

This EnviroAtlas dataset describes the total counts and percentage of population, land area, and impervious surface in the 1% Annual Chance Flood Hazard area or 0.2% Annual Chance Flood Hazard area of each block group. The flood hazard area is defined by the National Flood Hazard Layer (NFHL) produced by the Federal Emergency Management Agency (FEMA, www.fema.gov). This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk; classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to earth's surface using the UTM projection and coordinate system. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12,000.

These are the main layers that were used in the mapping and analysis for the Santa Monica Mountains Local Coastal Plan, which was adopted by the Board of Supervisors on August 26, 2014, and certified by the California Coastal Commission on October 10, 2014. Below are some links to important documents and web mapping applications, as well as a link to the actual GIS data:

Plan Website – This has links to the actual plan, maps, and a link to our online web mapping application known as SMMLCP-NET. Click here for website. Online Web Mapping Application – This is the online web mapping application that shows all the layers associated with the plan. These are the same layers that are available for download below. Click here for the web mapping application. GIS Layers – This is a link to the GIS layers in the form of an ArcGIS Map Package, click here (LINK TO FOLLOW SOON) for ArcGIS Map Package (version 10.3). Also, included are layers in shapefile format. Those are included below.

Below is a list of the GIS Layers provided (shapefile format):

Recreation (Zipped - 5 MB - click here)

Coastal Zone Campground Trails (2012 National Park Service) Backbone Trail Class III Bike Route – Existing Class III Bike Route – Proposed

Scenic Resources (Zipped - 3 MB - click here)

Significant Ridgeline State-Designated Scenic Highway State-Designated Scenic Highway 200-foot buffer Scenic Route Scenic Route 200-foot buffer Scenic Element

Biological Resources (Zipped - 45 MB - click here)

National Hydrography Dataset – Streams H2 Habitat (High Scrutiny) H1 Habitat H1 Habitat 100-foot buffer H1 Habitat Quiet Zone H2 Habitat H3 Habitat

Hazards (Zipped - 8 MB - click here)

FEMA Flood Zone (100-year flood plain) Liquefaction Zone (Earthquake-Induced Liquefaction Potential) Landslide Area (Earthquake-Induced Landslide Potential) Fire Hazard and Responsibility Area

Zoning and Land Use (Zipped - 13 MB - click here)

Malibu LCP – LUP (1986) Malibu LCP – Zoning (1986) Land Use Policy Zoning

Other Layers (Zipped - 38 MB - click here)

Coastal Commission Appeal Jurisdiction Community Names Santa Monica Mountains (SMM) Coastal Zone Boundary Pepperdine University Long Range Development Plan (LRDP) Rural Village

Contact the L.A. County Dept. of Regional Planning's GIS Section if you have questions. Send to our email.

description: The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). In addition to the preceding, required text, the Abstract should also describe the projection and coordinate system as well as a general statement about horizontal accuracy.; abstract: The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). In addition to the preceding, required text, the Abstract should also describe the projection and coordinate system as well as a general statement about horizontal accuracy.

In 2016, Los Angeles County embarked on an effort to update the 1996 LA River Master Plan to better address existing and new challenges along the river. The updated Plan was approved and adopted by the Los Angeles County Board of Supervisors in June 2022, which now serves as a guiding document for implementation efforts along the river. This Plan covers a wide range of social and environmental aspects of the LA River, the watershed, and the communities along the river through data-driven methodology. For more information on the updated LA River Master Plan (LARMP), please visit the LA River Master Plan website.Purpose:

To provide the public with information datasets used in the analysis for the updated LA River Master Plan.

Description:

The updated LA River Master Plan is organized by nine goals, each of which represents an equally important active future priority for the LA River. These goals were informed by a rich collection of data describing the physical, social, and cultural attributes of the LA River. Hundreds of datasets were referenced and applied within the Plan to provide critical understanding of community needs and mapping for specific goals. To view and access a wide range of dataset topics such as People Experiencing Homelessness, Water Quality Prioritization, Historical Ecologies of LA County, Arts and Culture Need, Flood Risk Reduction Need, Housing Affordability Need, Parks Need, Displacement Risk, Known Projects, Major Project Zones, and more, please visit the LA River Master Plan Data website.

A viewer intended to provide the public with information regarding the jurisdictional responsibilities of a variety of Public Works core services as well as links to key indicators for communities throughout the county. It should help a member of the public identify important PW services and help with identifying contact information for additional help. Jurisdictional boundaries include layers on infrastructure for a number of core Public Works areas of focus, such as:Flood ControlSewers and LandfillsTransporationWaterGarbage DisposalPublic Works FacilitiesInformation is also available for services in any given area using the "Service Locator".Information is available for communities and cities using "Community Profiles".

The Floodplain Mapping/Redelineation study deliverables depict and quantify the flood risks for the study area. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The Floodplain Mapping/Redelineation flood risk boundaries are derived from the engineering information Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). (Source: FEMA Guidelines and Specifications, Appendix M: Data Capture Standards (March, 2009))

Debris Basins are key components of the Los Angeles County Flood Control District's (LACFCD) flood control system. Typically located at the mouths of canyons, debris basins capture sediment, gravel, boulders, and vegetative debris that are washed out of the canyons during storms, protection lower lying communities from possible flooding and property damage. Due to the transitory changes in capacity and sediment, the DPW only provides point locations of its debris basins data. More information on dams and debris basins are available from the Los Angeles County Department of Public Works' Sediment Management website.

Hurricane Harvey made landfall near Rockport, Texas on August 25 as a category 4 hurricane with wind gusts exceeding 150 miles per hour. As Harvey moved inland the forward motion of the storm slowed down and produced tremendous rainfall amounts to southeastern Texas and southwestern Louisiana. Historic flooding occurred in Texas and Louisiana as a result of the widespread, heavy rainfall over an 8-day period in Louisiana in August and September 2017. Following the storm event, U.S. Geological Survey (USGS) hydrographers recovered and documented 2,123 high-water marks in Texas, noting location and height of the water above land surface. Many of these high-water marks were used to create flood-inundation maps for selected communities of Texas that experienced flooding in August and September, 2017.
The mapped area boundary, flood inundation extents, depth rasters, and coastal surge layer were created to provide an estimated extent of flood inundation in Coastal basins including East and West Matagorda Bay Subbasins, East and West San Antonio Bay Subbasins, and Aransas Bay Subbasin, Texas. The mapped area of the Coastal basins were separated into three sections based on the availability and location of high-water marks. The maps of the eastern part of the East Matagorda Bay Subbasin include a 17-mi reach of Peyton Creek and a 16-mi reach of Big Boggy Creek, and flood-inundation map for 6-mi reach of Little Boggy Creek in Matagorda County. The maps of the western part of East Matagorda Bay Subbasin include a 13.5-mi reach of West Carancahua Creek, 14.5-mi reach of East Carancahua Creek, and 9.6-mi reach of Keller Creek within Matagorda, Jackson, and Calhoun Counties. The maps of the middle part of the East Matagorda Bay Subbasin are for a 21-mi reach of the Tres Palacios River within Matagorda County. These geospatial data include the following items: 1. bnd_emb1, bnd_emb2, and bnd_tres_palacios; shapefiles containing the polygon showing the mapped area boundary for the Coastal basins flood maps, 2. hwm_emb_1, hwm_emb2, and hwm_tres_palacios; shapefiles containing high-water mark points used for inundation maps, 3. polygon_emb1, polygon_emb_2, and polygon_tres_palacios; shapefiles containing mapped extent of flood inundation for the Coastal basins, derived from the water-surface elevation surveyed at high-water marks, 4. depth_emb1, depth_emb2, and depth_tres; raster files for the flood depths derived from the water-surface elevation surveyed at high-water marks, and 5. coastal_surge.lyr; a layer file generated from the depth raster depicting water height above ground recorded at the high-water marks. The upstream and downstream mapped area extent is limited to the upstream-most and downstream-most high-water mark locations. In areas of uncertainty of flood extent, the mapped area boundary is lined up with the flood inundation polygon extent. The mapped area boundary polygon was used to extract the final flood inundation polygon and depth raster from the water-surface elevation raster file. Depth raster files were created using the "Topo to Raster" tool in ArcMap (ESRI, 2012). The HWM elevation data from the USGS Short-tern Network (STN) was used to create the flood water-surface raster file (U.S. Geological Survey [USGS], 2018, Short-Term Network Data Portal: USGS flood information web page, accessed February 13, 2018, at https://water.usgs.gov/floods/FEV.). The water-surface raster was the basis for the creation of the final flood inundation polygon and depth layer to support the development of flood inundation map for the Federal Emergency Management Agency's (FEMA) response and recovery operations.

The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to earth's surface using the State Plane projection and coordinate system. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12,000.

The National Weather Service issues warnings for severe weather that are imminent or actively occurring. This layer shows shorter-term warnings for the following events:Special Marine Warnings - potentially hazardous weather conditions of short duration (up to 2 hours) that may include sustained winds or gusts of 39 mph or greater, hail 0.75” or greater in diameter, or waterspouts.Severe Thunderstorm Warnings - storms with winds of 58 mph or higher or hail 1” or greater in diameter.Tornado Warnings - imminent or active tornados.Extreme Wind Warnings - surface winds of 115 mph or greater associated with non-convective, downslope, derecho, or sustained hurricane winds are expected to occur within one hour.Flash Flood Warnings - conditions are favorable for flash flooding. It does not mean that flash flooding will occur, but it is possible.SourceCurrent Warnings: https://www.weather.gov/source/crh/shapefiles/CurrentWarnings.tar.gzSample DataSee Sample Layer Item for sample data during Weather inactivity!Update FrequencyThe service is updated every 5 minutes using the Aggregated Live Feeds methodology.Area CoveredContiguous United StatesWhat can you do with this layer?Customize the display of each attribute by using the Change Style option for any layer.Query the layer to display only specific types of weather watches and warnings.Add to a map with other weather data layers to provide inside on hazardous weather events.Use ArcGIS Online analysis tools, such as Enrich Data, to determine the potential impact of weather events on populations.This map is provided for informational purposes and is not monitored 24/7 for accuracy and currency.If you would like to be alerted to potential issues or simply see when this Service will update next, please visit our Live Feed Status Page!

The National Weather Service issues warnings for severe weather that are imminent or actively occurring. This layer shows shorter-term warnings for the following events:Special Marine Warnings - potentially hazardous weather conditions of short duration (up to 2 hours) that may include sustained winds or gusts of 39 mph or greater, hail 0.75” or greater in diameter, or waterspouts.Severe Thunderstorm Warnings - storms with winds of 58 mph or higher or hail 1” or greater in diameter.Tornado Warnings - imminent or active tornados.Extreme Wind Warnings - surface winds of 115 mph or greater associated with non-convective, downslope, derecho, or sustained hurricane winds are expected to occur within one hour.Flash Flood Warnings - conditions are favorable for flash flooding. It does not mean that flash flooding will occur, but it is possible.SourceCurrent Warnings: https://www.weather.gov/source/crh/shapefiles/CurrentWarnings.tar.gzSample DataSee Sample Layer Item for sample data during Weather inactivity!Update FrequencyThe service is updated every 5 minutes using the Aggregated Live Feeds methodology.Area CoveredContiguous United StatesWhat can you do with this layer?Customize the display of each attribute by using the Change Style option for any layer.Query the layer to display only specific types of weather watches and warnings.Add to a map with other weather data layers to provide inside on hazardous weather events.Use ArcGIS Online analysis tools, such as Enrich Data, to determine the potential impact of weather events on populations.This map is provided for informational purposes and is not monitored 24/7 for accuracy and currency.If you would like to be alerted to potential issues or simply see when this Service will update next, please visit our Live Feed Status Page!