-
Difficulty:
-
-
Terrain:
-
Size: 
(not chosen)
Related Web Page
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
The Penobscot is the largest river in Maine and the second largest in New England (after the Connecticut). The river drains an 8,592 square-mile (22,252 km 2 ) watershed, roughly one-quarter of the state's land area.
There is plenty of parking at Bangor's Waterfront Park. This earth cache can easily be completed from a wheelchair at the coordinates and can even be done from the Handicapped parking closest to the coordinates.
• The mainstream of the river begins at the confluence of the East and West Branches at Medway and flows to Stockton Springs/Castine, where it opens up into Penobscot Bay.
• The Penobscot estuary is a classic drowned river valley: the prehistoric Penobscot began as glacial melt water, meandering east and west before finding its current course. The river carved a valley through granite and metamorphic rock, a valley which was later inundated by the rising postglacial sea.The Penobscot River estuary extends approximately from Bangor to Searsport/Bucksport where it meets Penobscot Bay. During extreme high tides and low flows, the tide may reach as far as Eddington Bend. With a surface area of over 23,000 acres, the Penobscot River estuary is the largest estuary in Maine and part of one of the largest embayment on the East Coast. The Penobscot is also a significant freshwater inflow to the Gulf of Maine, discharging 10 billion gallons per day (Hasbrouck, 1995).
The estuary is classified as partially mixed. River flow and tidal flow are balanced; salt and fresh water mix to some degree, although the lower layers of water remain saltier than the upper layers. Salinity is greatest at the mouth of the estuary and decreases upstream. The extent of salt water moves up and downstream tidally and seasonally, depending on freshwater flows. During high flows in April, fresh water can extend as far south as Winterport. As river discharge decreases and flood tides reach further up the estuary, salt water can be found in Hampden and Brewer. Salinity in the estuary is between 17 and 20 ppt; marine water has been observed in bottom layers of the estuary as far north as Bucksport (Haefner, 1967).
The transition zone between freshwater and marine environments is spatially small, but plays a disproportionately large role in the ecosystem. The estuary is a rich feeding environment for birds and fish, and the Penobscot eelgrass, salt marsh, and mudflats provide critical nursery habitat for countless species of fish larvae and adults. The estuary is the ecological bottleneck where migrating fish converge on their way upstream. The estuary is also a region of intense biochemical transformation of nutrients and contaminants (Casper, 2004).
Estuary Facts:
Mean depth: 29 ft (8.8 m)
Max depth: 101 ft (30.8 m)
Surface area: 23,600 acres (95.5 km2)
Volume (at MLW): 30 billion ft3 (850 million m3)
Mean tide: 6.5 ft at Bangor (2.0 m)
Great job, Medic Drew47... Congrats on 1st to complete… well done answers!
As an Earth Cache, there is no 'container’ to discover. Rather, with this cache, you discover something about the geology of the area.
Logging requirements:
Send an e-mail to me through my profile indicating the name of the Earth cache in the subject line and tell how many were in your group.
Please submit the following information:
Look for the high water mark on the bridge support of the Joshua Chamberlain Bridge; this is the green bridge, the middle of the 3 bridges you can observe from the Bangor Waterfront Park:
1. You will measure by guesstimate the distance from the high water mark on the cement pilons to the top of the support beams of the bridge.
2. Next you will measure by guesstimate the distance from the high water mark to the wet water mark. This will tell you the tidal flow at this point in time. What is the difference?
3. Using this point as a reference and observing the Penobscot River flow, do you think this tidal river is approaching a high or low tide? Explain your conclusion.
Bonus: Did you observe any estuary wildlife during your visit? Enjoy your visit to this Urban Earthcache!
References:
Casper, A.F. 2004. From the river to the sea – initial responses of the lower food web of the Kennebec River to dam removal and some implications for the Penobscot River-Estuary. Penobscot River Science Forum, October 19-20, 2004, Orono, ME.
Haefner, P.A. 1967. Hydrography of the Penobscot River (Maine) Estuary. J. Fish. Res. Bd. Canada 24:1553-1571. PDF
Hasbrouck, S. 1995. Maine Rivers and Streams. Geographical Digest Series #6, University of Maine Water Resources Program, Orono, ME.
Additional Hints
(No hints available.)