Buzard, R.M.Overbeck, J.R.2022report, dataReport of InvestigationRI 2022-5Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys22 p., 2 sheets, scale 1:50,000https://doi.org/10.14509/30908Coastal bluff stability assessment for Homer, Alaska, Report of Investigation 2022-5, evaluates the stability of coastal bluffs in Homer, Alaska, using aerial imagery and modern elevation data. We produce maps of historical shoreline change and an alongshore bluff instability hazard score. Shoreline change is calculated by comparing the bluff top and toe positions in historical and modern orthorectified aerial imagery. Since 1951, Homer's coastal bluffs have eroded at an average rate of -1.0 ft/yr (-0.29 m/yr). Key indicators of bluff instability are historical shoreline change rates, bluff slope and height, vegetation, existing erosion protection structures, and water drainage. Most of the Homer coastline has a low to medium bluff instability hazard score. These coastal hazard assessment products can guide decisions to reduce risk. These products are released as a DGGS publication component with an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30908).These coastal hazard assessment products can guide decisions to reduce risk.>baseline: Shore-parallel line from which transects are cast >bluff_toe_2019_bare_earth: Bluff toe delineated from 2019 digital elevation model >bluff_toe_all_veg: Bluff toe delineated from imagery >bluff_top_all_veg: Bluff top edge delineated from imagery >bluff_top_2019_bare_earth: Bluff top edge delineated from 2019 digital elevation model >DSAS_ave_rates: Average shoreline change of top and toe veg lines >DSAS_ave_rates_clip_toe: Same as DSAS_ave_rates, but transects clipped to bluff toe >DSAS_toe_rates: Shoreline change statistics for bluffToe_all_veg >DSAS_top_rates: Shoreline change statistics for bluffTop_all_veg >DSAS_transects: transects drawn perpendicular to Baseline to measure shoreline change. >slope_stability_transects: Alongshore transects with shoreline change statistics and instability scores19512022ground conditionCompleteUnknown-151.730844-151.37180059.68976159.631397ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysCoastalCoastal ErosionCoastal and RiverDGGSEngineeringEngineering GeologyEnvironmentEnvironmentalErosionGeodatabaseGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyGeotechnicalGroundwater EmergenceHazardsHydrologyImage InterpretationInterpretationLandslideMethodsSlidesSlopeSlumpSurfaceAlaska Division of Geological & Geophysical SurveysBeluga LakeBidarki CreekBluff PointCook InletDiamond CreekFritz CreekHomerKachemak BayLampert LakeShingle BeachThis report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.The Federal Emergency Management Agency (FEMA) provided funding through a Cooperative Agreement to the Alaska Division of Geological & Geophysical Surveys to complete this Coastal Bluff Stability Project under grant number EMS-2019-CA-00022-R05. We thank FEMA Cooperating Technical Partners Program, the City of Homer, and the Homer Planning Commission for supporting this work. Major improvements were made thanks to the thorough and insightful reviews by Bret Hig Higman, Chris Maio, Barrett Salisbury, and FEMA. Much of this study was possible thanks to the foundational work by Steve Baird and the Kachemak Bay National Estuarian Research Reserve.Buzard, R.M.2021Raw Data FileRDF 2021-21Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys10 phttps://doi.org/10.14509/30824Reger, R.D.1978Geologic ReportGR 61BFairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveysp. 5-9https://doi.org/10.14509/409Salisbury, J.B.Daanen, R.P.Herbst, A.M.2021Raw Data FileRDF 2021-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys6 phttps://doi.org/10.14509/30591Suleimani, E.N.Nicolsky, D.J.Salisbury, J.B.2019Report of InvestigationRI 2018-5 v. 2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys97 p., 11 sheetshttps://doi.org/10.14509/30095This assessment is based on remotely sensed products and semi-automated techniques. This approach allows for a consistent metric to be applied across broad scales, but it is less accurate at small scales because it is unsupervised. The results are appropriate for regional-scale assessments of hazards, but localized interpretations should be made with critical judgment. DGGS staff have performed visual qualitative and quantitative assessments of each digitized line, orthorectified image, and calculated output values to ensure geologically reasonable results. The coastal bluff stability maps highlight existing hazards and are tools to guide decisions to improve community safety. However, various factors that are unknown or difficult to quantify could impact bluff stability. The accompanying report provides additional information about the procedures used to determine uncertainty values for shoreline positions and shoreline change statistics.not applicableThis publication is part of a DGGS Report of Investigations (RI). An RI is the completed product of original research and analysis. RIs use professional cartography and undergo rigorous peer review, editing, and revision.The total uncertainty of each year's image orthorectification and shoreline delineation are quantified and discussed in the accompanying report. Users must recognize the scope and purpose of this study, the source data's limitations, and the uncertainties inherent to hazard modeling. We encourage users to reference the accompanying report when using the database output for purposes other than graphical displays.Himmelstoss, E.A.Farris, A.S.Henderson, R.E.Kratzmann, M.G.Ergul, AyhanZhang, OuyaZichichi, J.L.Thieler, E.R.2018Open-File ReportOF 2018-1179United StatesU.S. Geological Survey110 phttps://dggs.alaska.gov/pubs/id/30649ArcGIS extension2018publication dateHimmelstoss, E.A. and others, 2018data compilation and analysisData compilation and analysis - This analysis focuses on two goals: (1) calculate historical bluff erosion and (2) estimate current bluff stability. Historical bluff erosion is computed using orthorectified aerial imagery and the Digital Shoreline Analysis System (DSAS; Himmelstoss and others, 2018). Bluff stability is estimated by combining variables that factor into instability: height, slope angle, vegetation, drainage, erosion history, and shoreline armoring. A comprehensive description of the procedures and source data is available in the accompanying report.Himmelstoss, E.A. and others, 20182022vectorUniversal Transverse Mercator50.999600-1530500000.0000000coordinate pair.00000001.00000001MetersNAD83 (2011)GRS 806378137298.257222101baselineShore-parallel line from which transects are castDGGSbaselineDSAS_IDIdentification number of baselinethis reportLong Integerbluff_toe_2019_bare_earthBluff toe delineated from 2019 digital elevation modelDGGSbluff_toe_2019_bare_earthDSAS_dateApproximate shoreline acquisition datethis reportMM\DD\YYYYDSAS_uncyRelative uncertainty of shoreline delineationthis reportMetersbluff_toe_all_vegBluff toe delineated from imageryDGGSbluff_toe_all_vegDSAS_dateApproximate shoreline acquisition datethis reportMM\DD\YYYYDSAS_uncyRelative uncertainty of shoreline delineationthis reportMetersbluff_top_all_vegBluff top edge delineated from imageryDGGSbluff_top_all_vegDSAS_dateApproximate shoreline acquisition datethis reportMM\DD\YYYYDSAS_uncyRelative uncertainty of shoreline delineationthis reportMetersbluff_top_2019_bare_earthBluff top edge delineated from 2019 digital elevation modelDGGSbluff_top_2019_bare_earthDSAS_dateApproximate shoreline acquisition datethis reportMM\DD\YYYYDSAS_uncyRelative uncertainty of shoreline delineationthis reportMetersDSAS_ave_ratesAverage shoreline change of top and toe veg linesDGGSDSAS_ave_ratesTransectIDTransect identification numberthis reportLong IntegerAzimuthTransect angle clockwise from norththis reportDegreesTCDTotal cumulative distance of transect along baselinethis reportMetersEPR_aveAverage end point rate - the distance of oldest and youngest shorelines divided by timespanthis reportMeters per yearEPR_ave_uncUncertainty of end-point ratethis reportMeters per yearWLR_aveAverage weighted linear regression rate of change of the bluff toe and top edgethis reportMeters per yearWCI90_aveStandard error of weighted linear regression slope with 90 percent confidence intervalthis reportMeters per yearDSAS_ave_rates_clip_toeSame as DSAS_ave_rates, but transects clipped to bluff toeDGGSDSAS_ave_rates_clip_toeTransectIDTransect identification numberthis reportLong IntegerAzimuthTransect angle clockwise from norththis reportDegreesTCDTotal cumulative distance of transect along baselinethis reportMetersEPR_aveAverage end point rate - the distance of oldest and youngest shorelines divided by timespanthis reportMeters per yearEPR_ave_uncUncertainty of end-point ratethis reportMeters per yearWLR_aveAverage weighted linear regression rate of change of the bluff toe and top edgethis reportMeters per yearWCI90_aveStandard error of weighted linear regression slope with 90 percent confidence intervalthis reportMeters per yearDSAS_toe_ratesShoreline change statistics for bluff_toe_all_vegDGGSDSAS_toe_ratesTransectIDTransect identification numberthis reportLong IntegerBaselineIDIdentification number of baseline the transect was cast fromthis reportLong IntegerTransOrderTransect identification numberthis reportLong IntegerAzimuthTransect angle clockwise from norththis reportDegreesShrCountCount of shorelines used for statisticthis reportLong IntegerTCDTotal cumulative distance of transect along baselinethis reportMetersSCEShoreline change envelope - greatest distance between shorelinesthis reportMetersNSMNet-shoreline movement - distance between the oldest and youngest shorelinesthis reportMetersEPREnd point rate - distance of oldest and youngest shorelines divided by timespanthis reportMeters per yearEPRuncEnd point rate uncertaintythis reportMeters per yearLRRLinear regression rate of changethis reportMeters per yearLR2R-squared value of linear regressionthis reportDouble IntegerLSEStandard error of linear regressionthis reportMeters per yearLCI90Standard error of linear regression slope with 90 percent confidence intervalthis reportMeters per yearWLRWeighted linear regression rate of changethis reportMeters per yearWR2R-squared value of weighted linear regressionthis reportDouble IntegerWSEStandard error of weighted linear regressionthis reportMeters per yearWCI90Standard error of weighted linear regression slope with 90 percent confidence intervalthis reportMeters per yearDSAS_top_ratesShoreline change statistics for bluff_top_all_vegDGGSDSAS_top_ratesTransectIDTransect identification numberthis reportLong IntegerBaselineIDIdentification number of baseline the transect was cast fromthis reportLong IntegerTransOrderTransect identification numberthis reportLong IntegerAzimuthTransect angle clockwise from norththis reportDegreesShrCountCount of shorelines used for statisticthis reportLong IntegerTCDTotal cumulative distance of transect along baselinethis reportMetersSCEShoreline change envelope - greatest distance between shorelinesthis reportMetersNSMNet-shoreline movement - distance between the oldest and youngest shorelinesthis reportMetersEPREnd point rate - distance of oldest and youngest shorelines divided by timespanthis reportMeters per yearEPRuncEnd point rate uncertaintythis reportMeters per yearLRRLinear regression rate of changethis reportMeters per yearLR2R-squared value of linear regressionthis reportDouble IntegerLSEStandard error of linear regressionthis reportMeters per yearLCI90Standard error of linear regression slope with 90 percent confidence intervalthis reportMeters per yearWLRWeighted linear regression rate of changethis reportMeters per yearWR2R-squared value of weighted linear regressionthis reportDouble IntegerWSEStandard error of weighted linear regressionthis reportMeters per yearWCI90Standard error of weighted linear regression slope with 90 percent confidence intervalthis reportMeters per yearDSAS_transectstransects drawn perpendicular to Baseline to measure shoreline changeDGGSDSAS_transectsBaselineIDIdentification number of baseline the transect was cast fromthis reportLong IntegerTransOrderTransect identification numberthis reportLong IntegerAzimuthTransect angle clockwise from norththis reportDegreesslope_stability_transectsAlongshore transects with shoreline change statistics and instability scoresDGGSslope_stability_transectsprofileProfile numberthis reportShort integerprofStartXX coordinate of profile start pointthis reportNAD83 (2011) UTM Zone 5NprofStartYY coordinate of profile start pointthis reportNAD83 (2011) UTM Zone 5NprofEndXX coordinate of profile end pointthis reportNAD83 (2011) UTM Zone 5NprofEndYY coordinate of profile end pointthis reportNAD83 (2011) UTM Zone 5NtoeXX coordinate of bluff toe on profilethis reportNAD83 (2011) UTM Zone 5NtoeYY coordinate of bluff toe on profilethis reportNAD83 (2011) UTM Zone 5NtoeZElevation of bluff toe on profilethis reportNAD83 (2011) UTM Zone 5NtopXX coordinate of bluff top edge on profilethis reportNAD83 (2011) UTM Zone 5NtopYY coordinate of bluff top edge on profilethis reportNAD83 (2011) UTM Zone 5NtopZElevation of bluff top edge on profilethis reportMeters NAVD88 (GEOID12B)vegPercCoverPercentage of vegetation above 1.0 m tall on slopethis reportPercent (0 to 100)vegAveHeightAverage height of vegetation on slopethis reportMetersbluffHeightHeight of bluff from toe to top edgethis reportMetersbluffWidthWidth of bluff from toe to top edgethis reportMetersslopePercAngle of slope measured in slope percentthis reportSlope percentslopeDegAngle of slope measured in degreesthis reportDegreesEPRAverage end point rate - distance of oldest and youngest shorelines divided by timespanthis reportMeters per yearEPRUncUncertainty of end-point ratethis reportMeters per yearWLRAverage weighted linear regression rate of change of the bluff toe and top edgethis reportMeters per yearWCI90Standard error of weighted linear regression slope with 90 percent confidence intervalthis reportMeters per yearinstArmorInstability score due to lack of armoringthis report0 (very low) to 3 (high)instErosionInstability score due to erosionthis report0 (very low) to 3 (high)instSlopeInstability score due to slope angle and heightthis report0 (very low) to 3 (high)instVegInstability score due to lack of vegetationthis report0 (very low) to 3 (high)instDrainageInstability score due to drainagethis report0 (very low) to 3 (high)instCombineCombined instability scorethis report0 (very low) to 3 (high)Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.RI 2022-5The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.Contact DGGS for current pricingdatabasehttps://doi.org/10.14509/30908Free download20221216Alaska Division of Geological & Geophysical SurveysSimone MontayneMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions