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Granite Falls Advocate Tribune - Granite Falls, MN
  • New river gauge bumps up historical river crests

  • Historical river crests, flood stages and impact levels for the community of Granite Falls have all been bumped up six inches as a result of the installation of an automated river gauge.This past summer the City of Granite Falls, with the aid of a DNR flood mitigation dollars, commissioned the U.S. Geological Surve...
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  • Historical river crests, flood stages and impact levels for the community of Granite Falls have all been bumped up six inches as a result of the installation of an automated river gauge.
    This past summer the City of Granite Falls, with the aid of a DNR flood mitigation dollars, commissioned the U.S. Geological Survey (USGS) to install the automated river gauge below the 212 Bridge to allow for the collection of timely, up-to-date river level information.
    The USGS installed the device utilizing new data reference points (NAVD88 as opposed to NVGD29), which alter the river flood stages, historical crests and impact levels to the tune of a .54 foot increase, according to National Weather Service Hydrologist Diane Cooper.
    For simplicity's sake, the adjustments have been rounded to .5 feet for both flood stages and impact levels. Below are the new historical crests, flood stage and impact levels as a result of the change in reference points.
    Flood Stages old new
    Minor 888 888.5
    Moderate 893 893.5
    Major 896 896.5
    Historical crests old new
    1) 4/7/1997 899.3 899.84
    2) 4/12/1969 896 895.84
    3) 4/15/2001 895.3 895.84
    4) 4/10/1952 894.1 894.64
    5) 6/25/1919 893.7 894.24
    6) 4/7/2011 893.01 893.55
    7) 3/23/2010 892.58 893.12
    8) 4/14/1965 892.1 892.64
    9) 4/11/1951 891.9 892.44
    10) 4/27/2001 891.6 892.14
    Impact levels old new
    Flood waters begin to impact the low steel bridge on Hwy. 212
    899 899.5
    Flood waters begin to affect 11th Ave. west of GF, impacting Bootlegger's Supper Club
    892.5 893
    Flood Waters cause Hwy. 67 southeast of town to close
    891.5 892
    Flood waters begin to flow into natural diversion channel that begins upstream of GF and flow around western and southern section of the city
    891.1 891.6
    Flood waters begin to affect Hwy. 67 southeast of town
    891 891.5
    Flood waters beginning to top the controlling bank at Hwy. 212
    889 889.5
    Flood waters to encroach the alley way along the river at the footbridge
    888 888.5

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