Rock Tunnel Traditional Cache
GrayFinders2: Reconstruction still under way. New treatment technology is different than described in cache. Archiving to make room for a new one.
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Difficulty:
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Terrain:
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Size: 
(micro)
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“Bens Creek supports aquatic life all through its 42-square-mile drainage, but the number and diversity of species increases sharply below Thomas Mills, where drainage from the limestone-floored Hillman Mine enters. However, that boost comes at a price in the form of iron that coats the streambed and smothers organisms. SCRIP’s first treatment system – the Rock Tunnel Project – was built at Thomas Mills to keep much of that iron out of the stream. The Bens Creek headwaters have recently been affected by a different mine discharge farther upstream. The state Department of Environmental Protection has begun construction on a treatment system to address that problem. When Bens Creek joins the Stony Creek River just upstream of Ferndale, it’s increased pH helps neutralize the acidic effects of Shade and Paint creeks and greatly improves the river’s chemistry.” (Stony Creek River Improvement Project (SCRIP) website).
The Rock Tunnel Treatment System consists of a series of overflow and underflow weirs that allow the iron to drop out of the water on the upflow sections rather than fight gravity or to drop out on the downflow sections as the velocity slows after crossing over the weir (see attached sketch). The long central wood frame barrier forces the water to travel the length of the pond twice, providing more weirs and more opportunities for the iron to precipitate out. Unfortunately, higher than expected water levels submerge all of the weirs, allowing some of the flow to short circuit the system by flowing over top of all the weirs. The steep rocky outlet channel then helps to aerate the discharge before it enters the stream.
Its easiest to turn around later if you park at the driveway entrance end of the pond and walk the breast to the posted coordinates. This also gives you a better opportunity to see the weirs. The interior slopes of the pond are relatively steep, so exercise caution near the edges, especially with small children. If you can't follow instructions, see attributes.
Cache is a log only, pop top container in black electrical tape. Bring your own pen.
If snow cover closes the site access drive, the cache is NOT accessible. Blocking even one lane of a narrow rural road with your vehicle, particularly in poor weather conditions just to grab a cache, is dangerous and poor caching etiquette.
Additional Hints
(Decrypt)
prageny yrt