A line feature class of the county flood criteria boundaries within Miami-Dade County. The purpose of the Miami-Dade County Flood Criteria Map is to determine the minimum ground surface elevation of developed properties, crown/grade of roads, and secondary canal banks based on a 10-year, 24-hour storm event, 2060 scenario with SLR, and the minimum top elevation of seawalls, unless higher elevations are required by other regulatory applicable standards. Available for review and comment October 22, 2021 through December 22, 2021.Updated: Every 10 yrs The data was created using: Projected Coordinate System: WGS_1984_Web_Mercator_Auxiliary_SphereProjection: Mercator_Auxiliary_Sphere

A polygon feature class of the Coastal A Zone boundaries. Developed to aid the spatial location of the Coastal A Zones in Miami-Dade County for permitting purposes. Based on the Miami-Dade County Digital Flood Insurance Rate Map (DFIRM), effective September 11, 2009 published by FEMA and the ASCE 24 guidelines. 'Coastal A� Zone according to FEMA, is the area landward of a V Zone or landward of an open coast without mapped V Zones. In a coastal A Zone, the principal source of flooding will be astronomical tides, storm surges, seiches or tsunamis and not riverine flooding. During base flood conditions, the potential for breaking wave heights between 1.5 feet and 3.0 ft, will exist.Updated: Not Planned The data was created using: Projected Coordinate System: WGS_1984_Web_Mercator_Auxiliary_SphereProjection: Mercator_Auxiliary_Sphere

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).

A line feature class of the county flood criteria boundaries within Miami-Dade County, adopted by the County Commission in 1982.Updated: Every 10 yrs The data was created using: Projected Coordinate System: WGS_1984_Web_Mercator_Auxiliary_SphereProjection: Mercator_Auxiliary_Sphere

Updated FEMA Flood Mapping for Broward County, FL. This is a preliminary assessment of updates to Flood Zones from December 2019.

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.

This dataset, called FloodPop, contains estimates of the population and housing in high flood hazard areas in the contiguous US at the Census block, tract, county, and state levels as well as classified building footprints and validation data. The dataset corresponds with the forthcoming manuscript entitled “High-resolution estimates of the US population in high fluvial flood hazard areas”.

Note: The folders building_footprints.gdb, building_footprints_df, and validation/ buildings_w_lu.gdb contain modified building footprints from Overture Maps (https://overturemaps.org/), including information from OpenStreetMap (https://www.openstreetmap.org/), USA Structures, the National Structure Inventory, and the US release of Microsoft Building footprints. The data in building_footprints.gdb, building_footprints_df, and validation/buildings_w_lu.gdb are made available under the Open Database License (ODbL) v1.0 (https://opendatacommons.org/licenses/odbl/1-0/), while the rest of the repository is made available under the CC BY 4.0 license (https://creativecommons.org/licenses/by/4.0/) .

Contents

fp_summaries: FloodPop results in tabular and geospatial formats. Each file in this folder has columns from the original census dataset at the corresponding spatial scale and similar added columns.

Files • blocks_by_state.gdb: An Esri file geodatabase containing a feature class of FloodPop results at the Census block level for each state. State abbreviations are at the beginning of the feature class name. • cartographic.gdb: An Esri file geodatabase containing feature classes representing cartographic tract, county, and state level FloodPop estimates. The feature classes should be used for visualization but not used for analysis. • summaries.gdb: An Esri file geodatabase containing feature classes representing tract, county, and state level FloodPop estimates. The feature classes can be used for analysis. • summary_csvs: Comma Separated Value (CSV) files containing FloodPop estimates for Census blocks, tracts, counties, and states. This folder also contains a CSV (state_res_or_not_summary.csv) that summarizes the sources of building classifications by state, parsing out the count and area of buildings for residential (res_or_not = 1), non-residential (res_or_not = 0), and unknown (res_or_not = -1) buildings.

Added columns For files in the fp_summaries folder, estimates of the population, total housing units, and occupied housing units were appended to census data boundaries. Census variables “p1_001n” (total population), “h1_001n” (total housing units), and “h1_002n” (occupied housing units) were added to all census boundaries. Then, columns were added for each census variable intersecting each scenario of estimated flood hazard (SFHA, best-available SFHA, and either SFHA). Lower and upper bounds were calculated for population and occupied housing units but not for total housing units as block-level counts for total housing units did not have privacy noise added. Columns related to population use the prefix “pop_”, total housing units uses “tot_hu_”, and occupied housing units uses “occ_hu_”. An example of the naming convention for population estimate columns is below, and this was replicated for total housing units (without upper and lower bounds) and occupied housing units: • pop_sfha: Estimated population within the FEMA Special Flood Hazard Area (SFHA). • pop_sfha_low: Lower bounds (90% CI) of estimated population within the FEMA Special Flood Hazard Area (SFHA). • pop_sfha_high: Upper bounds (90% CI) of estimated population within the FEMA Special Flood Hazard Area (SFHA). • pop_best_sfha: Estimated population within the FEMA SFHA (if mapped by FEMA) or the estimated SFHA (if not mapped by FEMA). • pop_best_sfha_low: Lower bounds (90% CI) of estimated population within the FEMA SFHA (if mapped by FEMA) or the estimated SFHA (if not mapped by FEMA). • pop_best_sfha_high: Upper bounds (90% CI) of estimated population within the FEMA SFHA (if mapped by FEMA) or the estimated SFHA (if not mapped by FEMA). • pop_either_sfha: Estimated population within either the FEMA SFHA or estimated SFHA. • pop_either_sfha_low: Lower bounds (90% CI) of estimated population within either the FEMA SFHA or estimated SFHA. • pop_either_sfha_high: Upper bounds (90% CI) of estimated population within either the FEMA SFHA or estimated SFHA.

Additional columns for block-level results • out_sfha_area: Building footprint area (m2) that does not intersect the SFHA. • within_sfha_area: Building footprint area (m2) that intersects the SFHA. • ratio_area_sfha: The ratio of total building footprint area that intersects the SFHA. • out_est_sfha_area: Building footprint area (m2) that does not intersect the estimated SFHA. • within_est_sfha_area: Building footprint area (m2) that intersects the estimated SFHA. • ratio_area_est_sfha: The ratio of total building footprint area that intersects the estimated SFHA. • out_best_sfha_area: Building footprint area (m2) that does not intersect the best-available SFHA. • within_best_sfha_area: Building footprint area (m2) that intersects the best-available SFHA. • ratio_area_best_sfha: The ratio of total building footprint area that intersects the best-available SFHA. • out_either_sfha_area: Building footprint area (m2) that does not intersect either SFHA. • within_either_sfha_area: Building footprint area (m2) that intersects either SFHA. • ratio_area_either_sfha: The ratio of total building footprint area that intersects either SFHA. • ci_low: Lower bounds estimate (90% CI) of block population. • ci_high: Upper bounds estimate (90% CI) of block population. • ci_low_hu: Lower bounds estimate (90% CI) of block occupied housing units. • ci_high_hu: Upper bounds estimate (90% CI) of block occupied housing units.

validation: Folder containing geodatabases used for the presented validation exercises that focus on Mecklenburg County, NC, Miami-Dade County, FL, and Sacramento, CA. • buildings_w_lu.gdb: Modified Overture Maps building footprints for the validation area with land use classifications from local datasets. • input_cities.gdb: Parcels with classified land use from local datasets. • sj_cities.gdb: Parcels that intersect modified Overture Maps building footprints for the validation area. • validation_blocks.gdb: FloodPop estimates for census blocks that intersect modified Overture Maps building footprints for the validation area.

building_footprints.gdb: An Esri file geodatabase containing classified building footprint feature classes for each state used to create FloodPop estimates. Each footprint contains information on building classification, presence within the SFHA, estimated SFHA, and FEMA study footprint, and Census block. State abbreviations are at the beginning of the feature class name.

building_footprint_dfs: Folder containing a tabular version (Parquet format) of building footprints for each state. State abbreviations are at the beginning of the file name.

A polygon feature class of the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) map panels for Miami-Dade County.Updated: Every 10 yrs The data was created using: Projected Coordinate System: WGS_1984_Web_Mercator_Auxiliary_SphereProjection: Mercator_Auxiliary_Sphere

Public Facing Web Application for Flood Zone in Brevard County

FEMA Flood Hazard Area - Zone A This map shows the area that have a 1% chance of flooding each year. This map is a combination of the FEMA flood layers from Hamilton, Suwannee, and Columbia Counties. For more information on this map and others in the series for the Flood Extent Mapping for the Suwannee River at White Springs, please contact Kelly Godsey, Senior Service Hydrologist with the National Weather Service in Tallahassee at Kelly.Godsey@noaa.gov

The flooding in the greater New Orleans area that resulted from Hurricanes Katrina and Rita in September, 2005, left behind accumulations of sediments up to many centimeters thick on streets, lawns, parking lots, and other flat surfaces. These flood sediment deposits have been the focus of extensive study by the US Environmental Protection Agency (EPA) and Louisiana Department of Environmental Quality (LDEQ) due to concerns that the sediments may contain elevated levels of heavy metals, organic contaminants, and microbes.

The U.S. Geological Survey (USGS) is characterizing a limited number of flood sediment samples that were collected on September 15-16 and October 6-7, 2005, from the greater New Orleans area by personnel from the USGS Louisiana Water Science Center in Baton Rouge. Small samples (< 3 pints each) of wet to dry flood sediment were collected from 11 localities around downtown New Orleans on September 15, 2005, and two large samples (40 pints each) of wet flood sediment were collected from the Chalmette area on September 16. Twelve additional samples (8-10 pints each) were collected from New Orleans, Slidell, Rigolets, and Violet on October 6 and 7.

The USGS characterization studies of these flood sediments are designed to produce data and interpretations regarding how the sediments and any contained contaminants may respond to environmental processes. This information will be of use to cleanup managers and DoI/USGS scientists assessing environmental impacts of the hurricanes and subsequent cleanup activities.

[Summary provided by the USGS.]

Large amounts of rain fell on southern Maine from the afternoon of April 15, 2007, to the afternoon of April 16, 2007, causing substantial damage to houses, roads, and culverts. This report provides an estimate of the peak flows on two rivers in southern Maine - the Mousam River and the Little Ossipee River because of their severe flooding. The April 2007 estimated peak flow of 9,230 ft per second at the Mousam River near West Kennebunk had a recurrence interval between 100 and 500 years; 95-percent confidence limits for this flow ranged from 25 years to greater than 500 years. The April 2007 estimated peak flow of 8,220 ft per second at the Little Ossipee River near South Limington had a recurrence interval between 100 and 500 years; 95-percent confidence limits for this flow ranged from 50 years to greater than 500 years.

[Summary provided by the USGS.]

Lake Mack Flood Zones in Lake County FL.

Lead-rich sediments, containing at least 1000 ppm of lead (Pb), and derived mainly from discarded mill tailings in the Coeur d'Alene mining region, cover about 60 km2 of the 80-km2 floor of the main stem of the Coeur d'Alene River valley, in north Idaho. Although mill tailings have not been discarded directly into tributary streams since 1968, frequent floods continue to re-mobilize sediment from large secondary sources, previously deposited on the bed, banks, alluvial terraces, and natural levees of the river. Thus, lead-rich sediments (also enriched in iron, manganese, zinc, copper, arsenic, cadmium, antimony and mercury) continue to be deposited on the floodplain. This is hazardous to the health of resident and visiting human and wildlife populations, attracted by the river and its lateral lakes and wetlands.

This report documents and compares depositional rates and lead concentrations of lead-rich sediments deposited on the bed, banks, natural levees, and flood basins of the main stem of the Coeur d'Alene River during several time-stratigraphic intervals. These intervals are defined by their stratigraphic positions relative to the base of the section of lead-rich sediments, the 1980 Mt. St. Helens volcanic-ash layer, and the sedimentary surface at the time of sampling. Four important intervals represent sediment deposition during the following time spans (younger to older): 1. Baseline, from 1980 to about 1993 (after tailings disposal to streams ended, but before any major removals of lead-rich sediments); 2. Early post-tailings-release, from about 1968 to 1980; 3. Historic floodplain-contamination, from about 1903 to 1968; and 4. Background, before the 1893 flood (the first major flood after large-scale mining and milling began upstream in 1886).

Medians of baseline depositional rates and lead concentrations in levee sediments vary laterally, from 6.4 cm/10y and 3300 ppm Pb on riverbanks and levee fore-slopes to 2.8 cm/10y and 3800 ppm Pb on levee back-slope uplands. In lateral flood basins, baseline medians increase with water depth, from 2.2 cm/10y and 1900 ppm Pb in lateral marshes, to 2.9 cm/10y and 2100 ppm Pb in littoral margins of lateral lakes, and 4.0 cm/10y and 4400 ppm Pb on limnetic bottoms of lateral lakes.

The median of lead concentrations in baseline sediments is 82 percent of the median for early post-tailings-release sediments, with a 69-percent probability that the two data sets represent statistically different populations. By contrast, the median of lead concentrations in baseline sediments is 57 percent of the corresponding median for historic-interval sediments, and these two data sets definitely represent statistically different populations. The area-weighted average of medians of lead concentrations in baseline sediments of all depositional settings is 2900 ppm Pb, which is 1.6 times the 1800 ppm Pb that can be lethal to waterfowl. It also is 2.9 times the 1000-ppm-Pb threshold for removal of contaminated soil from residential yards in the Coeur d'Alene mining region, and 111 times the 26-ppm median of background lead concentrations in pre-industrial floodplain sediments.

During episodes of high discharge, lead-rich sediments will continue to be mobilized from large secondary sources on the bed, banks, and natural levees of the river, and will continue to be deposited on the floodplain during frequent floods. Floodplain deposition of lead-rich sediments will continue for centuries unless major secondary sources are removed or stabilized. It is therefore important to design, sequence, implement, and maintain remediation in ways that will limit recontamination.

[Summary provided by the USGS.]