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ICE EFFECTS ON STREAMFLOW
The formation of ice on rivers can cause discharge values to appear unusually high. Display of these erroneous discharge data may result in improper assessment of flow conditions and misuse of the data. For this reason, display of discharge values for streams significantly affected by ice may be disabled from view. Display of discharge data will resume when ice conditions are no longer present. Discharge values for streams minimally affected by ice will continue to be displayed. Flows for streams with these conditions appear to increase during the night and decrease to near-base-line conditions around midday. To estimate the correct discharge for these streams, use the flow rate that corresponds to the bottom of the discharge curve, rather than the peak that corresponds to the top of the curve. Note that this method of estimation is possible only when no surface runoff is occurring. Daily mean discharges for periods of both significant and minimal ice-effect will be estimated and published in the Annual Water-Data Report for the water year in which they occurred.
71o24'44", Middlesex County,
Hydrologic Unit 01070005, 30 ft north of State Highway 2 and 150 ft
east of Wetherbee Street in Acton.
AQUIFER--Sand and gravel, glaciated regions; ice contact deposits aquifer.
WELL CHARACTERISTICS--Augered observation water-table well, diameter 2.0 in., depth 33.8 ft, screened 31.8 to 33.8 ft.
INSTRUMENTATION--Data Collection Platform with satellite telemeter, June 2001 to current year. Monthly measurement prior to June 2001.
DATUM--Elevation of land-surface datum is 153 ft above National Geodetic Vertical Datum of 1929, from topographic map.
PERIOD OF RECORD--January 1965 to current year. Prior to October 1974, published in Massachusetts Hydrologic-Data Report No. 17.
COOPERATION BY--Massachusetts Department of Conservation and Recreation, Office of Water Resources.