U.S. Department of the Interior U.S. Geological Survey Inter-Agency Datum Establishment and Conversion Collaboration in Missouri. Paul H. Rydlund Jr. PLS U.S. Geological Survey Missouri Water Science Center 2013 National Height Modernization Partner Meeting Western States Regional Webinar

What’s the problem? Reporting vertical datum differences generates confusion and depreciates public confidence.Reporting vertical datum differences generates confusion and depreciates public confidence.

What’s the problem? Reporting vertical datum differences generates confusion and depreciates public confidence.Reporting vertical datum differences generates confusion and depreciates public confidence. River Forecasting For example….

What’s the problem? Public welfare regarding impactsPublic welfare regarding impacts

What’s the problem? Cooperative agencies all disseminate vertical datum for reference of hydrologic products. Consistency (and accuracy) is needed.Cooperative agencies all disseminate vertical datum for reference of hydrologic products. Consistency (and accuracy) is needed.

What’s the problem? Levee overtopping concerns exist where USGS streamgage datum and datum for levee surveys differ.Levee overtopping concerns exist where USGS streamgage datum and datum for levee surveys differ. For example…. Public Protection Level

What’s the problem? Inundation mapping, whether agency function or private sector, is dependent upon datum representing consistency and quality.Inundation mapping, whether agency function or private sector, is dependent upon datum representing consistency and quality.

USGS Policy Guidance NAVD88 is the recommended datum established in the Federal Geographic Data framework (USGS - Office of Water Information Technical memorandum ).

USGS Database Statistics 1.84,944 Surface-Water sites  62,032 determined elevation from maps  7,737 from levels  8,023 unknown source  1,269 from a GPS 2.4,771 already reported to NAVD88

NGS-USGS-NWS-USACE Streamgage Datum Workgroup Workgroup interaction and support for datum conversion of USGS streamgages to NAVD 88Workgroup interaction and support for datum conversion of USGS 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 heightWhat method to measure/compute/derived updated height Create guidelines that other regions/districts can useCreate guidelines that other regions/districts can use

NGS-USGS-NWS-USACE Streamgage 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 resourcesMethod for conversion – driven by accuracy requirements and resources 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 Conversion or Survey – “The USGS Missouri Model” Cooperative Interest Cooperative Interest Gage location hydraulics or channel instability 1. Evaluation of Source Datum Source Datum 2. Cooperative Interest Interest 3. Hydraulics and Stability and Stability 4. Accuracy assured with USACE ‘CEPD’ with USACE ‘CEPD’ and NWS modeling and NWS modeling interests interests Source Datum genesis and condition Accuracy

NWK SWL MVL MVS MVM USACE MODOT MDNR Inter-Agency Collaboration in Missouri

Missouri River Datum Discrepancy Example Inter-Agency Collaboration in Missouri

Continuing Inter-Agency Collaboration in Missouri – FY 13 USACE – SWL USGS - MOWSC USGS - ARWSC

Continuing Inter-Agency Collaboration in Missouri – FY 13

Inter-Agency Collaboration in Missouri – FY 14

 Datum 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 of NGVD 29 and NAVD 88 datum Dissemination of NGVD 29 and NAVD 88 datum Inter-Agency Collaboration

Datum Surveys – Assistance and Collaboration

Inter-Agency Collaboration Datum Surveys – Assistance and Collaboration

Benefits of Inter-Agency Collaboration Enhance Resources Enhance Resources Reduce Expense Reduce Expense Quality Assurance Quality Assurance Agency Consensus Agency Consensus Public Approval Public Approval

USGS Resources – Questions? USGS Global Positioning System Web Committee