USGS Water-Year Summary 2023

390945091494001 Mexico

Cambrian-Ordovician aquifer system
Champlainian Series

LOCATION - Lat 39°09'45.1", long 91°49'40.6" referenced to North American Datum of 1983, in NE 1/4 NW 1/4 NE 1/4 sec.32, T.51 N., R.8 W., Audrain County, MO, Hydrologic Unit 07110006,

REVISIONS HISTORY -
Revisions: Land-surface datum was updated to 817.24 ft NAVD88 on May 22, 2023, as determined by a GNSS survey by Missouri DNR. Land-surface datum was previously published as 815 ft NAVD88 from topographic map. Discrete water-level measurements prior to May 22, 2023, are referenced to the original datum.

The data from 10/06/2000 to 12/14/2009 was modified after it was previously set to 'Approved'. A -2.00 ft measuring point height correction was applied to this data on 11/15/2010. It was discovered the reported measuring point height of 0.00 ft was in error after a QA site visit and the needed correction was applied.

GROUNDWATER RECORDS

DATUM - Land-surface datum is 817.24 ft above North American Vertical Datum of 1988. Measuring point: unknown, 2.0 ft above land-surface datum, Oct. 24, 2001 to present.  

PERIOD OF RECORD - 10/06/2000 to present.

GAGE - From 10/06/2000 to present, DCP with telemetry capability. From 10/06/2000 to February 23, 2005, water level measuring device is float driven encoder. From February 23, 2005 to present, the water level measuring device is a vented, submersible pressure transducer.

COOPERATION - Data furnished by Missouri Department of Natural Resources (MDNR).

REMARKS - Data from 10/06/2000 to 12/14/2009 has been processed by the USGS using 27 field water level measurements made during the period to verify the recorded water levels. The record from 10/06/2000 to 02/23/2005 is considered fair because the float frequently 'sticks' in the well for short periods of time. Data from 02/23/2005 to 12/14/2009 since the pressure tranducer was installed is considered good. Data from 12/14/2009 to 07/08/2010 is good based on 4 water level measurements made in the well to verify the recorded data and is accurate to +/- 0.05 ft. Data from 07/08/2010 to 10/17/2011 is good based on 3 water level measurements made in the well to verify the recorded data and is accurate to +/- 0.10 ft. Data from 10/17/2011 to 07/29/2012 is good based on 4 water level measurements made in the well to verify the recorded data and is accurate to +/- 0.10 ft. Data from 07/30/2012 to 11/25/2013 is good based on 4 water level measurements made in the well to verify the recorded data and is accurate to +/- 0.05 ft. The record from 11/26/2013 to 07/08/2014 is good based on 4 water level measurements made during the period to verify the recorded data and is accurate to +/- 0.10 ft. The record from 07/09/2014 to 01/27/2016 is good based on 4 water level measurements made during the period to verify the recorded data and is accurate to +/- 0.05 ft. The record from 01/28/2016 to 11/13/2016 is good based on 2 water level measurements made during the period to verify the recorded data and is accurate to +/- 0.05 ft. The record from 11/14/2016 to 08/01/2017 is good based on 2 water level measurements made during the period to verify the recorded data and is accurate to +/- 0.05 ft. The record from 08/02/2017 to 01/23/2018 is good based on 1 water level measurement made during the period to verify the recorded data and is accurate to +/- 0.10 ft. The record from 01/24/2018 to 02/13/2018 is good based on 1 water level measurement made during the period to verify the recorded data and is accurate to +/- 0.10 ft. The record from 02/14/2018 to 08/22/2018 is good based on 1 water level measurement made during the period to verify the recorded data and is accurate to +/- 0.05 ft. The record from 08/23/2018 to 03/13/2019 is good based on 1 water level measurement made during the period to verify the recorded data and is accurate to +/- 0.05 ft. The record from 03/14/2019 to 09/22/2019 is good based on 1 water level measurement made during the period to verify the recorded data and is accurate to +/- 0.10 ft. 

All further remarks can be found in RMS as of 09/23/2019.