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Home My WebLink About11-18-19 City Commission Packet Materials - C16. Res 5113, Establishing North American Vertical Datum as City's Vertical Datum1 REPORT TO: Mayor and City Commission FROM: Chris Saunders, Community Development Manager Martin Matsen, Director of Community Development Mitch Reister, Director of Public Works SUBJECT: Approval of Resolution 5113 to establish NAVD88 as the City’s vertical datum in coordination with Ordinance 2032. STRATEGIC PLAN: Implements strategic plan 7.3.c to utilize best practices and improve departmental collaboration. MEETING DATE: November 18, 2019 AGENDA ITEM TYPE: Consent (legislative) RECOMMENDATION: Meets standards for approval. BACKGROUND: The City Commission provisionally approved Ordinance 2032 October 28, 2019. The ordinance replaces the City’s vertical datum used for surveying and engineering design. The packet materials are available at http://weblink.bozeman.net/WebLink8/0/doc/198035/Electronic.aspx. The current BMC sections reference vertical data points which no longer exist, and it is in the interest of the City and public welfare to establish a common datum for all City uses. The City relies upon the vertical datum to set how any point in an infrastructure project relates in the third dimension of height to other locations throughout the City. This is especially critical for water related projects where accurate grades determine whether a project is functional or not. As the City has more intensive development accurate computer modeling of the existing and future utility systems will play an increasing role. Such computer models are essential in providing accurate maintenance investments, scheduling expansion and upgrades of existing facilities, and determining where development potential may be limited. Section 34.01.010 calls for adoption of a vertical datum upon recommendation of the Director of Public Works. The Director recommends the City Commission adopt the NAVD88 standard at this time. UNRESOLVED ISSUES: None. ALTERNATIVES: As suggested by the City Commission. Commission Memorandum 215 2 FISCAL EFFECTS: None Attachments: Resolution 5113 NAVD88 summary NSRS One page summary Report compiled on November 4, 2019 216 Page 1 of 2 RESOLUTION 5113 A RESOLUTION OF THE CITY COMMISSION OF THE CITY OF BOZEMAN, MONTANA, ESTABLISHING NORTH AMERICAN VERTICAL DATUM OF 1988 (NAVD88) AS THE CITY’S VERTICAL DATUM. WHEREAS, the City of Bozeman has established Section 34.01.010, BMC authorizing adoption of a vertical datum by resolution of the City Commission; and WHEREAS, NAVD88 is the national standard for surveying and engineering vertical control; and WHEREAS, the City Commission finds that NAVD88 will provide a more consistent and reliable standard for City engineering and surveying purposes, MCA. NOW, THEREFORE, BE IT RESOLVED by the City Commission of the City of Bozeman, Montana, to wit: Section 1 The City hereby adopts the North American Vertical Datum of 1988 as the City’s vertical datum. Section 2 This Resolution once adopted supersedes any previously used vertical datum. 217 Page 2 of 2 Section 3 This Resolution is effective on the same day as Ordinance 2032. PASSED, ADOPTED, AND APPROVED by the City Commission of the City of Bozeman, Montana, at a regular session thereof held on the 18th day of November, 2019. CYNTHIA L. ANDRUS Mayor ATTEST: ROBIN CROUGH City Clerk APPROVED AS TO FORM: GREG SULLIVAN City Attorney 218 North American Vertical Datum of 1988 (NAVD 88) The North American Vertical Datum of 1988 (NAVD 88) is the vertical control datum established in 1991 by the minimum-constraint adjustment of the Canadian-Mexican-United States leveling observations. It held fixed the height of the primary tidal bench mark, referenced to the new International Great Lakes Datum of 1985 local mean sea level height value, at Father Point/Rimouski, Quebec, Canada. Additional tidal bench mark elevations were not used due to the demonstrated variations in sea surface topography, i.e., the fact that mean sea level is not the same equipotential surface at all tidal bench marks. North American Vertical Datum of 1988 (NAVD 88) consists of a leveling network on the North American Continent, ranging from Alaska, through Canada, across the United States, affixed to a single origin point on the continent. In 1993 NAVD 88 was affirmed as the official vertical datum in the National Spatial Reference System (NSRS) for the Conterminous United States and Alaska (see Federal Register Notice (FRN)). Although many papers on NAVD 88 exist, no single document serves as the official defining document for that datum. Detailed information about NAVD 88 is available here. Datum Information Tide Station Pointe-au-Pere, Rimouski Tide Station Location Quebec, Canada PID TY5255 Geodetic Survey of Canada Designation 54L071 Bench Mark 1250 G Ht above LMSL (meters) 6.271Note: The Vertical Mark Number (VM) and Permanent IDentifier (PID) shown on the bench mark sheet are unique identifiers for bench marks in the CO-OPS and NGS databases, respectively. For bench marks where both VM and PID are indicated, both tidal and geodetic vertical datum elevations are available. Datums and Reference Frames Overview Vertical Datums Horizontal and Geometric Datums New Datums 2022 Coordinate Conversion and Transformation Tool VERTCON v2.1 Tidal Datums (CO-OPS) 219 National Oceanic and Atmospheric Administration l National Geodetic SurveyNSRS NOAA’s National Geodetic Survey (NGS) defines, maintains, and provides access to the National Spatial Reference System (NSRS)— a consistent coordinate system that defines latitude, longitude, height, scale, gravity, orient- ation, and shoreline throughout the United States and is designed to meet our nation’s economic, social, and environmental needs. For 200 years, NGS and its predecessor agencies have collaborated with public and private organizations to establish reference stations at precisely determined locations. Traditionally, these locations have been identified by setting a survey mark—usually a brass, bronze, or aluminum disk. Locations might also be identified by a deeply driven rod or a prominent object, such as a water tower or church spire. More recently, NGS has fostered a network of continuously operating reference stations (CORS) where each CORS includes a highly accurate receiver that continuously collects radio signals broadcast by Global Navigation Satellite System (GNSS) satellites. Components of the NSRS include: n geodetic positional coordinates (latitude, longitude, and ellipsoid and orthometric heights) in the official U.S. datums, currently, the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88); n geopotential; n acceleration of gravity; National Geodetic Survey Positioning America for the Future geodesy.noaa.gov n deflection of the vertical; n models, tools, and guidelines; n the official national shoreline; n Global Navigation Satellite System (GNSS) orbits; n orientation, scale, and offset information relating NAD 83 to international terrestrial reference systems; and n all necessary information to describe how these values change over time. The reference stations form a network used to accurately position other points of interest. Surveyors, mapping professionals, and others use the NSRS to ensure their positional coor- dinates are compatible with those determined by others. In this way, when individuals create maps; mark property boundaries; and plan, design, and build roads, bridges, and other structures, everything matches up. For more information, contact NGS: geodesy.noaa.gov NOAA Manages the National Spatial Reference System NOAA Manages the 220