Regulatory floodplains are extracted from FEMA or provided by consultants to the City. Non regulatory floodplains are provided by consultants, but their accuracy is not guaranteed.FEMA floodplains can either be amended by Letters of Map Revision (LOMR), or Physical Map Revisions (PMR). Historic data between 7/17/1978 and 5/31/2018 rely on PMRs to FIRM Panels; from 5/31/2018 onwards, FEMA exposed a web API that made tracking LOMRs much easier. This is why changes to the floodplain after this date look more "piecemeal" rather than entirely replaced. FEMA Floodplains are automatically updated by a scripted process on a monthly basis.High Hazard Zones are solely recognized by the city as areas which represent the highest risk to loss of life. More information can be found here. These zones are delineated by engineering firms on behalf of the city. They are updated manually by GIS staff.Non-Regulatory Floodplains are updated infrequently.Data: Records with Null INEFFDATEs are the current floodplains.FLOODZONEs beginning with "A" have a 1% chance of flooding (e.g. the 100 Year floodplain)FLOODZONEs equal to "X" are areas with a 0.2% chance of flooding (e.g. the 500 Year floodplain)FLOODZONEs equal to "HHZ" are the High Hazard ZonesFLOODWAYs equal to 1 are Conveyance Zones
U.S. Government Workshttps://www.usa.gov/government-works
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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).
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Following the 2013 flood, the Colorado Water Conservation Board (CWCB) initiated a program to re-map the predicted 1% chance regulatory floodplain (100-year flood zone) of the most affected waterways. The program was named the "Colorado Hazard Mapping Program" or "CHAMP." This has been adopted by the Boulder County Commissioners, and will be used for regulatory decisions by the county. Not necessarily used for determining flood insurance.
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The 2013 urban flood extent data was developed using field surveys completed by City of Boulder staff and consultants, Digital Globe Worldview-2 satellite imagery (9/13/13), and public input from the Boulder Crowd Sourcing online map as well as discussions with affected property owners. Only drainages with a FEMA mapped floodplain were surveyed. Other areas of Open Space and Mountain parks land without a regulatory floodplain were not included.The flood extent data is current as of 3/28/2014 and includes information received from recent community meetings. The City of Boulder will make additional updates to this data to incorporate relevant information.The 2013 urban flood extent data does not supersede the Special Flood Hazard Area Designation (SFHA), or 100 yr floodplain, used by FEMA for Digial Flood Insurance Rate Maps or the proposed floodplain delineations from ongoing flood studies.This data is provided as graphical representation only. The City of Boulder provides no warranty, expressed or implied, as to the accuracy and/or completeness of the information contained hereon.
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Following the 2013 flood, the Colorado Water Conservation Board (CWCB) initiated a program to re-map the predicted 1% chance regulatory floodplain (100-year flood zone) of the most affected waterways. The program was named the "Colorado Hazard Mapping Program" or "CHAMP." This has been adopted by the Boulder County Commissioners, and will be used for regulatory decisions by the county. Not necessarily used for determining flood insurance.
SummaryThe City of Boulder recognizes two categories of regulatory floodplains: (1) Those released by the Federal Emergency Management Agency (FEMA) on Flood Insurance Rate Map (FIRM) Panels, and (2) High Hazard Zones. Non-regulatory floodplains include delineations from 10-, 25-, 50-, and 200-Year flood events. Effective dates for non regulatory floodplains are provided, but not guaranteed.Regulatory floodplains are extracted from FEMA or provided by consultants to the City. Non regulatory floodplains are provided by consultants, but their accuracy is not guaranteed.FEMA floodplains can either be amended by Letters of Map Revision (LOMR), or Physical Map Revisions (PMR). Historic data between 7/17/1978 and 5/31/2018 rely on PMRs to FIRM Panels; from 5/31/2018 onwards, FEMA exposed a web API that made tracking LOMRs much easier. This is why changes to the floodplain after this date look more "piecemeal" rather than entirely replaced. FEMA Floodplains are automatically updated by a scripted process on a monthly basis.High Hazard Zones are solely recognized by the city as areas which represent the highest risk to loss of life. More information can be found here. These zones are delineated by engineering firms on behalf of the city. They are updated manually by GIS staff.Non-Regulatory Floodplains are updated infrequently.Data: FLOODZONEs beginning with "A" have a 1% chance of flooding (e.g. the 100 Year floodplain)FLOODZONEs equal to "X" are areas with a 0.2% chance of flooding (e.g. the 500 Year floodplain)ZONE_SUBTY equal to FLOODWAY are conveyance zones
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FEMA DFIRM (Digital Flood Insurance Rate Map) cross sections effective December 18, 2012, created for Boulder County and all municipalities within under the direction of the FEMA Map Modernization project. This data supercedes all other flood data.Per FEMA: Data included on this CD-ROM represents Final Flood Insurance Rate Map (FIRM) data that has been published as effective FIRM or DFIRM information. The data are the official and legal representation of the effective flood zones.Boulder County added a field, "Regulating Entity" to distinguish this from Boulder County regulatory floodplain.
Rainfall on 9–13 September 2013 triggered at least 1,138 debris flows in a 3430 km 2 area of the Colorado Front Range. Most flows were triggered in response to two intense rainfall periods, one 12.5-hour-long period on 11–12 September, and one 8-hour-long period on 12 September. Data in this project pertain to an area bounded by N 40.0° – 40.375° and W 105.25° – 105.625° which includes many of the areas where high concentrations of debris flows occurred. These data include a subset of a map of landslide and debris flow scarps (Coe and others, 2014) and raster grids derived from the National Elevation Dataset. These data were used to test a new, parallel implementation of the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS, see Baum and others, 2010) for the timing and distribution of rainfall-induced shallow landslides. The data accompany an interpretive paper published in the journal Environmental Modeling & Software (Alvioli and Baum,2016)
Data licence Germany – Attribution – Version 2.0https://www.govdata.de/dl-de/by-2-0
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The hazard warning map shows flood areas and intensities (water depth or specific runoff) in extreme floods for the Elbe river and the I. Ordnung waters in Saxony on an overview scale (1:100,000) with a data level of 2004. Extreme flooding (EHQ) is an event that is significantly larger than HQ(100), at least the highest observed event, but generally HQ(300). Flood areas were calculated without taking into account the effect of existing flood protection systems, such as dams, dikes or polders. The illustrated intensities and extensions represent an enveloping of all possible flood scenarios, i.e. not all illustrated areas are affected by a single event. This also applies in the event of a failure of protective devices. In addition, the limits of the flooded areas at HQ(20) and HQ(100) are shown, also without taking into account the effect of flood protection devices. Due to the different flooding and thus damage processes, a distinction was made between shallow valley areas (slide-free, mostly non-run-changing flooding) and steep areas (dynamic flooding with boulder transport, erosion and expected run-change). Since the flood depth at the steep water sections can only indirectly give a statement about the intensity and thus about the hazard, the flow velocity on the forelands was additionally determined. The product of flood depth and flow velocity is represented as a specific runoff (runoff per metre water width) for EHQ.
The map and descriptions offer information that may be used for: land-use planning (e.g. selecting land fill sites, greenbelts, avoiding geologic hazards), for finding aggregate resources (crushed rock, sand, and gravel), for study of geomorphology and Quaternary geology. Geologic hazards (e.g., landslides, swelling soils, heaving bedrock, and flooding) known to be located in, or characteristic of some mapped units, were identified.
Surficial deposits in the quadrangle partially record depositional events of the Quaternary Period (the most recent 1.8 million years). Some events such as floods are familiar to persons living in the area, while other recorded events are pre-historical. The latter include glaciation, probable large earthquakes, protracted drought, and widespread deposition of sand and silt by wind. At least twice in the past 200,000 years (most recently about 30,000 to 12,000 years ago) global cooling caused glaciers to form along the Continental Divide. The glaciers advanced down valleys in the Front Range, deeply eroded the bedrock, and deposited moraines (map units tbg, tbj) and outwash (ggq, gge). On the plains (east part of map), eolian sand (es), stabilized dune sand (ed), and loess (elb) are present and in places contain buried paleosols. These deposits indicate that periods of sand dune deposition alternated with periods of stabilized dunes and soil formation.
Thirty-nine types of surficial geologic deposits and residual materials of Quaternary age are described and mapped in the greater Denver area, in part of the Front Range, and in the piedmont and plains east of Denver, Boulder, and Castle Rock. Descriptions appear in the pamphlet that accompanies the map. Landslide deposits, colluvium, residuum, alluvium, and other deposits or materials are described in terms of predominant grain size, mineral or rock composition (e.g., gypsiferous, calcareous, granitic, andesitic), thickness of deposits, and other physical characteristics. Origins and ages of the deposits and geologic hazards related to them are noted. Many lines between geologic units on our map were placed by generalizing contacts on published maps. However, in 1997-1999 we mapped new boundaries, as well. The map was projected to the UTM projection. This large map area extends from the Continental Divide near Winter Park and Fairplay ( on the west edge), eastward about 107 mi (172 km); and extends from Boulder on the north edge to Woodland Park at the south edge (68 mi; 109 km).
Compilation scale: 1:250,000. Map is available in digital and print-on-demand paper formats. Deposits are described in terms of predominant grain size, mineralogic and lithologic composition, general thickness, and geologic hazards, if any, relevant geologic historical information and paleosoil information, if any. Thirty- nine map units of deposits include 5 alluvium types, 15 colluvia, 6 residua, 3 types of eolian deposits, 2 periglacial/disintegrated deposits, 3 tills, 2 landslide units, 2 glaciofluvial units, and 1 diamicton. An additional map unit depicts large areas of mostly bare bedrock.
The physical properties of the surficial materials were compiled from published soil and geologic maps and reports, our field observations, and from earth science journal articles. Selected deposits in the field were checked for conformity to descriptions of map units by the Quaternary geologist who compiled the surficial geologic map units.
FILES INCLUDED IN THIS DATA SET:
denvpoly: polygon coverage containing geologic unit contacts and labels. denvline: arc coverage containing faults. geol_sfo.lin: This lineset file defines geologic line types in the geologically themed coverages. geoscamp2.mrk: This markerset file defines the geologic markers in the geologically themed coverages. color524.shd: This shadeset file defines the cmyk values of colors assigned to polygons in the geologically themed coverages.
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Following the 2013 flood, the Colorado Water Conservation Board (CWCB) initiated a program to re-map the predicted 1% chance regulatory floodplain (100-year flood zone) of the most affected waterways. The program was named the "Colorado Hazard Mapping Program" or "CHAMP." This has been adopted by the Boulder County Commissioners, and will be used for regulatory decisions by the county. Not necessarily used for determining flood insurance.
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The original source was the inundated areas as drawn by the National Geospatial Agency, which only covered major flooding along Boulder Creek and St Vrain Creek. This was supplemented by Boulder County Land Use and Parks and Open Space using imagery from the Digital Globe First Look product. Multiple images, taken on different days were used to determine the high water mark due to cloud cover. The high water mark has not been field verified. Inundated areas in the mountains were particularlly difficult to draw due to cloud and tree cover. Areas within the City of Longmont and Boulder were not drawn as it is assumed these cities will be creating their own layer. Areas within the other incorporated areas were drawn: Jamestown, Lyons, Louisville, Lafayette, and Erie. This dataset has further been refined by using Pictometry imagery flown October 2013 after the flood and using damage assessment data points. This dataset is updated as of 8/6/2014.
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This geographic dataset was updated by Boulder County Sheriff's Office Communications staff during summer 2023, to be WEA compliant and to provide coverage of all major waterways in Boulder County, including areas of City of Longmont and Town of Erie into Weld County (covered by BRETSA 911). We collaborated with Boulder County Sheriff's Office Law and Emergency Services personnel, Law/Police officials from most legal cities or towns, Boulder County Fire Districts, and Boulder Office of Emergency Management within our Public Safety Answering Point's area of authority that are susceptible to flooding events. This dataset is intended to be a flood hazard set of pre-created areas for reverse 911 notifications, for life safety purposes. The emergency responder (FIRE/LAW) would notify the BOCO 911 Communications Center about which zones to evacuate in the event of a flooding emergency. The 911 dispatch staff could use these pre-created flood hazard polygons to send a reverse notification to the area of interest. Steps to incorporate the areas of flood interest included: 1.) Obtaining new hydrological models for recently burned areas due to 2020 CalWood Fire burn scar; 2.) Utilizing Colorado Water Conservation Board post 2013-flood data (CHAMP) to unerstand updated flood risk; 3.) Meeting with publlic safety stakeholders to review their local areas of interest during collaborative working sessions, incorporating stakeholder feedback; 4.) Applying a 1/8 mile buffer to such areas of modeled interest; 5.) Simplifying edges of flood polygons to be Wireless Emergency Alert compliant; 6.) Importing the data into the emergency reverse notification tool and reviewing the resulting boundaries to ensure citizens are appropriately included in the areas of interest.
Date of Images: 3/10/2019 Date of Next Image: Unknown Purpose/Summary: Water extent map produced using the Moderate Resolution Imaging Spectrometer (MODIS). Flood image is produced by comparing images before (2/2/2018) and after (3/10/2019) the event to determine where flooding has occurred.Suggested Usage:Red pixels are classified as water. These are flooded areas that are normally dry land. This product is best used with a layer or background map with known water that is prevalent throughout the year to determine where the flooding is occurring. Satellite/Resolution: Moderate Resolution Imaging Spectrometer (MODIS); 250m resolution Credits: Brakenridge, G.R. and Kettner, A.J., March 18, 2019, "DFO Flood Event 4725", Dartmouth Flood Observatory, University of Colorado, Boulder, Colorado, USA, http://floodobservatory.colorado.edu/Events/4725/2019Malawi4725.html.
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The total amount of rain that fell in Boulder County during the September Flood of 2013, from September 10 to September 16. This information was aquired by NOAA, Earth System Research Laboratory, Physical Science Division, Climate Analyis Branch, and taken from there web page titled Boulde area flood of September 2013: Precipitation. This information is from the Advanced Hydrological Prediction Service. The URL of the this page is http://www.esrl.noaa.gov/psd/boulder/flood2013/precipplots/This page showed the total accumlation precpitation fro the period starting 12 UTC 9/9/2013 and ending 12 UTC 9/16/2013. There is a 6 hour time difference from UTC to Mountain Daylight Time, so map shows the total accumlation from 9/8 at 6:00PM to 9/16 at 6:00 PM. Process:The data was in .png file format and would need to be converted to .tif file for use in ArcMap.Add the raster dataset that you want to align in ArcMap.Add a layer that resides in your current map coordinates. For our purposes, the County boundary was used.Add the georeferencing toolbar.Using the georeferencing toolbar, Add control points that link known raster positions to your existing data.Save the georeferenced image when satisfied.Repeat for each of the precipitation rasters.Create feature classes for each raster timeframe.The following fields were added to record the precipitation amounts.RainfallMinRainfallMaxDigitize or sketch a polygon defining the features shape.Update the attributes for each field, using the precipitation amounts available in the raster legend.
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Regulatory floodplains are extracted from FEMA or provided by consultants to the City. Non regulatory floodplains are provided by consultants, but their accuracy is not guaranteed.FEMA floodplains can either be amended by Letters of Map Revision (LOMR), or Physical Map Revisions (PMR). Historic data between 7/17/1978 and 5/31/2018 rely on PMRs to FIRM Panels; from 5/31/2018 onwards, FEMA exposed a web API that made tracking LOMRs much easier. This is why changes to the floodplain after this date look more "piecemeal" rather than entirely replaced. FEMA Floodplains are automatically updated by a scripted process on a monthly basis.High Hazard Zones are solely recognized by the city as areas which represent the highest risk to loss of life. More information can be found here. These zones are delineated by engineering firms on behalf of the city. They are updated manually by GIS staff.Non-Regulatory Floodplains are updated infrequently.Data: Records with Null INEFFDATEs are the current floodplains.FLOODZONEs beginning with "A" have a 1% chance of flooding (e.g. the 100 Year floodplain)FLOODZONEs equal to "X" are areas with a 0.2% chance of flooding (e.g. the 500 Year floodplain)FLOODZONEs equal to "HHZ" are the High Hazard ZonesFLOODWAYs equal to 1 are Conveyance Zones