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|Prairie Island Observation Well PI98-14|
|Township:||Welch (T114N R16W)|
|Location:||0.17 miles northeast of Prairie Island Boulevard, 2.02 miles east if the intersection of Co. Rd. 68 and Co. Rd. 54|
|Land-surface elevation:||688.16 feet, NAVD88|
|Installation:||Sep. 3, 1998, By the USGS|
|Open interval:||15.4–19.6 feet|
|Original and current use:||monitoring, USGS|
|Type:||surficial sand and gravel|
|Thickness:||more than 22 feet (0–>22 feet, BLS)|
|Deposit:||sand and gravel alluvium deposited by a glacial melt-water stream|
Water levels below land surface are accurate to 0.01 feet. Water levels above National American Vertical Datum of 1988 (sea level) are calculated by subtracting recorded water levels from the land surface elevation, which is accurate only to plus-or-minus 0.01 feet based on optical level survey. Water-level differences are accurate to within 0.001 feet.
Note: The water levels measured at this field site are accurate only to a precision of two decimal places, not the 3 decimal places shown on this web site. Thus, the three-decimal place data do not reflect the absolute accuracy of the water level but only relative differences in the water level over time. This three-decimal place precision was useful at sites similar to this one for hydrologic analyses such as estimation of ground-water recharge and evapotranspiration.
Water temperatures are accurate to plus-or-minus 0.1°C.
Shelter temperature is the air temperature inside the shelter, which is unventilated, and does not represent ambient air temperature, particularly during daylight hours.
Precipitation is accurate to 0.01 inches except during freezing periods (about Dec. through early Apr.). The rain gage is unheated and uncovered. The precipitation data during freezing periods result from melting of snow (accumulated in the rain gage) during warm periods and do NOT represent actual precipitation. Precipitation totals during freezing periods May underestimate actual totals because the rain gage funnel may be full of snow (preventing further accumulation) or because snow in the funnel may sublimate instead of melt.