William L Finley National Wildlife Refuge EarthCache
William L Finley National Wildlife Refuge
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Coordinates listed are to the parking. You will need to walk onto the Prairie Overlook viewing platform to answer questions. The Willamette Floodplain, and the wet prairie here were designated a National Natural Landmark by the National Park Service.
The source of much of the Willamette’s fertility is derived from a series of massive ice age floods that came from Glacial Lake Missoula in Montana and scoured across Eastern Washington, sweeping its topsoil down the Columbia River Gorge. When floodwaters met log-and-ice jams at Kalama, in southwest Washington, the water caused a backup that filled the entire Willamette Valley to a depth of 300 to 400 feet above current sea level.Some geologists suggest that the Willamette Valley flooded in this manner multiple times during the last ice age.The lake gradually drained away, leaving layered sedimentary soils on the valley floor to a height of about 180 to 200 feet above current sea level throughout the Willamette valley.
An alluvial plain is a relatively flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms. A floodplain is part of the process, being the smaller area over which the rivers flood at a particular period of time, whereas the alluvial plain is the larger area representing the region over which the floodplains have shifted over geological time.
Floodplains can support particularly rich ecosystems, both in quantity and diversity. They are a category of riparian zones or systems. A floodplain can contain 100 or even 1000 times as many species as a river. Wetting of the floodplain soil releases an immediate surge of nutrients: those left over from the last flood, and those that result from the rapid decomposition of organic matter that has accumulated since then. Microscopic organisms thrive and larger species enter a rapid breeding cycle. Opportunistic feeders (particularly birds) move in to take advantage. The production of nutrients peaks and falls away quickly; however the surge of new growth endures for some time. This makes floodplains particularly valuable for agriculture.
Markedly different species grow in floodplains than grow outside of floodplains. For instance, riparian trees (that grow in floodplains) tend to be very tolerant of root disturbance and tend to be very quick-growing, compared to non-riparian trees.
Less than 1% of the Willamette Valley Wet Prairie still exists. The best example of this is located in William L. Finley Wildlife Refuge. Wet prairies are rare and endangered in the Pacific Northwest due to being converted to agricultural land, invasive plant species and urbanization.
Wet prairies are usually located in areas with poorly draining soil or soil that shallowly covers bedrock and is prevented from draining. They flood during one part of the year and are maintained by these seasonal floods. Previously, seasonal fires also kept the vegetation down. Finley has the largest, continuous tract of native wet prairie in the Willamette Valley.
Populations of several threatened and endangered species live in the refuge along with a herd of Roosevelt Elk.
To log this cache, spend some time on the viewing platform. Send me an email with the following:
1. Is this an area of poorly draining soil or shallow soil over bedrock? What are you basing your answer on? 2.Look around at the side of the ditch nearby. Can you see the different layers in the soil? What are the colors? How thick is each layer?
3. Do you see evidence of human alteration of the prairie (not counting Refuge facilities)? What are they?
4. On one of the signs at the site, it describes how both the Kalapuyans and the US Fish and Wildlife service are alike in managing the land. What is it that they do alike?
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