Slide 19 of 35
Notes:
Generalized flow paths for the 1998-present Curry Village Rockslides
In August of 1997, the temporary treatment system above Happy Isles was replaced with a permanent treatment system located in a topographic bowl not visible in this picture, but located near the words “1998-present leach field” in the upper right corner of the photograph.
The dominant discontinuity set at Glacier Point not only controls the angle and shape of the top of the cliff, dipping generally to the east (left) in this photograph, but members of this set are clearly visible in the photograph dipping from the vicinity of the 1998-present leach field toward the rockslide release area. Water can be seen emanating from the fractures in the rock in pictures taken following the November 1998 (and later) rockslide events. Calculations indicate that as little as 400 to 800 gallons of water are capable of triggering the Curry Village slides and as much as 5000 gallons of water per day are entering the leach field during peak tourist seasons.
It should be noted that from spring through mid summer, the public restrooms are closed and porta-potties are used because the leach field remains saturated. It is not known to us, what other facilities use this leach field but it likely that the gift shop and café are among them. It is highly unlikely that snowmelt would continue to saturate the soil in this area in June and July based on elevation and watershed size. Paving and other ground modification also appear to have increased surface water runoff into the topographic bowl.
