U.S. Department of the InteriorU.S. Geological Survey

Inter-Agency Datum Establishment and Inter-Agency Datum Establishment and Conversion Collaboration in Missouri.Conversion Collaboration in Missouri.

Paul H. Rydlund Jr. PLSPaul H. Rydlund Jr. PLSU.S. Geological SurveyU.S. Geological SurveyMissouri Water Science CenterMissouri Water Science Center

2013 National Height Modernization Partner Meeting2013 National Height Modernization Partner MeetingWestern States Regional WebinarWestern States Regional Webinar

What’s the problem?What’s the problem?

• Reporting vertical datum differences generates Reporting vertical datum differences generates confusion and depreciates public confidence.confusion and depreciates public confidence.

What’s the problem?What’s the problem?

• Reporting vertical datum differences generates Reporting vertical datum differences generates confusion and depreciates public confidence.confusion and depreciates public confidence.

River ForecastingRiver Forecasting

For example….For example….

What’s the problem?What’s the problem?

• Public welfare regarding impactsPublic welfare regarding impacts

What’s the problem?What’s the problem?

• Cooperative agencies all disseminate vertical datum for Cooperative agencies all disseminate vertical datum for reference of hydrologic products. Consistency reference of hydrologic products. Consistency ((and and accuracyaccuracy)) is needed. is needed.

What’s the problem?What’s the problem?

• Levee overtopping concerns exist where USGS Levee overtopping concerns exist where USGS streamgage datum and datum for levee surveys differ.streamgage datum and datum for levee surveys differ.

For example….For example….

Public Protection LevelPublic Protection Level

What’s the problem?What’s the problem?

• Inundation mapping, whether agency function or private Inundation mapping, whether agency function or private sector, is dependent upon datum representing sector, is dependent upon datum representing consistency and quality.consistency and quality.

USGS Policy GuidanceUSGS Policy Guidance

NAVD88 is the recommended datum established NAVD88 is the recommended datum established in the Federal Geographic Data framework in the Federal Geographic Data framework

(USGS - Office of Water Information Technical (USGS - Office of Water Information Technical memorandum 2002.01). memorandum 2002.01).

USGS Database StatisticsUSGS Database Statistics

1.1. 84,944 Surface-Water sites84,944 Surface-Water sites

62,032 determined elevation from maps62,032 determined elevation from maps 7,737 from levels7,737 from levels 8,023 unknown source 8,023 unknown source 1,269 from a GPS1,269 from a GPS

2.2. 4,771 already reported to NAVD884,771 already reported to NAVD88

NGS-USGS-NWS-USACE NGS-USGS-NWS-USACE Streamgage Datum WorkgroupStreamgage Datum Workgroup

• Workgroup interaction and support for datum conversion of Workgroup interaction and support for datum conversion of USGS streamgages to NAVD 88USGS streamgages to NAVD 88• Driven by “unfunded mandate” to update gage datumsDriven by “unfunded mandate” to update gage datums• Pilot states of Missouri, North Carolina, and MichiganPilot states of Missouri, North Carolina, and Michigan

• GoalsGoals• Establish decision model:Establish decision model:

• How to prioritize gages to update?How to prioritize gages to update?• How to determine accuracy needed?How to determine accuracy needed?• What method to measure/compute/derived updated What method to measure/compute/derived updated

heightheight• Create guidelines that other regions/districts can useCreate guidelines that other regions/districts can use

NGS-USGS-NWS-USACE NGS-USGS-NWS-USACE Streamgage Datum WorkgroupStreamgage Datum Workgroup

• Site Priority – driven by need and resourcesSite Priority – driven by need and resources• Cooperative Interest – needed by multiple agenciesCooperative Interest – needed by multiple agencies• Location, e.g. high population areas subject to floodingLocation, e.g. high population areas subject to flooding• Accuracy Requirement – dictate method for conversionAccuracy Requirement – dictate method for conversion

• Method for conversion – driven by accuracy requirements and Method for conversion – driven by accuracy requirements and resourcesresources• Rename datumRename datum• Simplistic Height Conversion Tool: VERTCON, CORPSCONSimplistic Height Conversion Tool: VERTCON, CORPSCON• GNSS SurveyGNSS Survey• LevelingLeveling

• RoadblocksRoadblocks• Lack of resources regarding personnel, expertise, and fundingLack of resources regarding personnel, expertise, and funding

NAVD 88 Datum Conversion : Simple Height NAVD 88 Datum Conversion : Simple Height Conversion or Survey – “The USGS Missouri Model”Conversion or Survey – “The USGS Missouri Model”

Cooperative Interest

Cooperative Interest

Gage locationhydraulics or channel instability

1. Evaluation of 1. Evaluation of Source DatumSource Datum

2. Cooperative 2. Cooperative InterestInterest

3. Hydraulics 3. Hydraulics and Stabilityand Stability

4. Accuracy assured4. Accuracy assured with USACE ‘CEPD’with USACE ‘CEPD’ and NWS modeling and NWS modeling interestsinterests

Source Datum genesis and condition

Accuracy

NWKNWK

SWLSWL

MVLMVL

MVSMVS

MVMMVM

USACEUSACE

MODOTMODOT

MDNRMDNR

Inter-Agency Collaboration in MissouriInter-Agency Collaboration in Missouri

Missouri River Missouri River Datum DiscrepancyDatum DiscrepancyExampleExample

Inter-Agency Collaboration in MissouriInter-Agency Collaboration in Missouri

Continuing Inter-Agency Collaboration in Continuing Inter-Agency Collaboration in Missouri – FY 13Missouri – FY 13

USACE – SWLUSACE – SWLUSGS - MOWSCUSGS - MOWSCUSGS - ARWSCUSGS - ARWSC

Continuing Inter-Agency Collaboration in Continuing Inter-Agency Collaboration in Missouri – FY 13Missouri – FY 13

Inter-Agency Collaboration in Missouri – FY 14Inter-Agency Collaboration in Missouri – FY 14

Datum Surveys – Moving ForwardDatum Surveys – Moving Forward

USGS and USACE duplicative surveys at important gaging locations Main stem Missouri and Mississippi River gages Water resource operation project gages Limited duplication at tributary gages

USGS / USACE surveys Sharing of metadata and results Overcome cost prohibitive gaging locations Augmenting staff for local/regional GNSS campaigns

USGS Gaging Installation Installation of an observable benchmark

Dissemination ofNGVD 29 andNAVD 88 datum

Dissemination ofNGVD 29 andNAVD 88 datum

Inter-Agency Collaboration

Inter-Agency Collaboration

Datum Surveys – Assistance and CollaborationDatum Surveys – Assistance and Collaboration

http://www.ngs.noaa.gov/ADVISORS/AdvisorsIndex.shtmlhttp://www.ngs.noaa.gov/ADVISORS/AdvisorsIndex.shtml

Inter-Agency Collaboration

Mark.W.Huber@usace.army.milMark.W.Huber@usace.army.milDatum Surveys – Assistance and CollaborationDatum Surveys – Assistance and Collaboration

Benefits of Inter-Agency Collaboration

Enhance ResourcesEnhance Resources

Reduce ExpenseReduce Expense

Quality AssuranceQuality Assurance

Agency ConsensusAgency Consensus Public ApprovalPublic Approval

USGS Resources – Questions?

http://water.usgs.gov/usgs/osw/gps/

USGS Global Positioning System Web CommitteeUSGS Global Positioning System Web Committee