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USGS Grindstone Gaging Station EarthCache

Hidden : 04/27/2007
2 out of 5
2 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

Welcome to the Grindstone USGS Gaging Station Hydrologic Unit 01020002 on the East Branch of the Penobscot River in Penobscot County, Maine.

This EarthCache will give you some understanding of what this little building is used for in Maine.  There are two meanings for hydrographs both coming from hydro- meaning water, and -graph meaning chart. A hydrograph plots the discharge of a river over time. This can be in response to single event such as a flood.


A hydrograph is a time record of the discharge of a stream, river or watershed outlet. Rainfall or snow melt are typically the main input to a watershed and the streamflow is often considered the output of the watershed; a hydrograph is a representation of how a watershed responds to rainfall or snow melt. They are used in hydrology and water resources planning.


During times of potential flooding, field crews from the U.S. Geological Survey (USGS) race to gather vital hydrologic data. They measure the river flow and water levels to provide the information needed by river forecasters, engineers, and emergency managers who rely on data from the USGS network of about 70 Maine streamflow-gaging stations The network is funded in a cooperative program of federal, State, and local agencies, and is part of a national network maintained by the USGS. Many of these stations are equipped to transmit real-time streamflow data. In times of emergency, real-time streamflow information is a key element in the protection of lives and property.


This station monitors the watershed east of Baxter State Park and is located just above Grindstone Falls on the East Branch of the Penobscot River.  The East Branch begins near the headwater of the Allagash River at East Branch Pond.



    Drainage area: 837.00 square miles

    Contributing drainage area: 1,086.0 square miles,

    Datum of gage: 294.74 feet above sea level   NGVD29.


This gaging station is operated and maintained in cooperation with:

Maine Emergency Management Agency

Maine River Flow Advisory Commission.

The U.S. Geological Survey


REALTIME FOR THE GRINDSTONE GAGE: Real-time data typically are recorded at 15-60 minute intervals, stored onsite, and then transmitted to USGS offices every 1 to 4 hours, depending on the data relay technique used. Recording and transmission times may be more frequent during critical events. Data from real-time sites are relayed to USGS offices via satellite, telephone, and/or radio and are available for viewing within minutes of arrival at either of these two webpages.


Site #1                         Site #2


To log this EarthCache: You must post a photo of your GPS with the gage house in the background.  Then email the owner the height at the nearest time of your visit and the volume of discharge at that time.

If you enjoy this earthcache you may want to check the Maine Geological Survey located at They have developed a number of information sheets or field localities giving a great deal of information about geologic features. They also have a number of books and maps about Maine’s natural history/ geology that you might find interesting.

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