Chinquapin Water Supply Test Well Installation
A test well would be drilled in the Chinquapin area, approx. 40' south of the Ranger residence on the west side of Wawona Rd. (site #1). If site #1 well proves to have insufficient water, then a 2nd test well would be drilled east of Wawona Rd, at site #2, on the S. side of Indian Ck, (within 20' of an existing, but insufficient capped well (ca. 1982)). Monitoring wells and devices will be installed near the test well(s) to monitor potential impacts.
The test well would be up to 6" diameter, up to 1000' deep. If the test well hits sufficient water it will ultimately serve as a monitoring well calculating the safe yield for a (future) production well. The well(s) would be installed using an air rotary drilling rig (50k- 55k lbs, 45' long truck). A support truck with casing and most of the drill pipe would be parked either end-to-end relative to the rig or at 90 degrees. An auxiliary air compressor will be parked near the rig. Access to site #1 is along the access road for the Ranger Residence. Cuttings and water ejected from the hole may be routed through a diverter pipe at the surface and then run through a cyclone separator (mounted on the rig) or run through an approved silt fence containment system. Cuttings will be disposed of by NPS at an approved site. Testing involves pumping the well constantly for 15-20 days, with monitoring. The water will be disposed of as follows: after discharge into a hopper and separated from cuttings the water would be pumped out of the hopper to a small temporary holding area to allow sediments to drop out, the run through several small impoundment areas lined with filter fabric before being discharged into a nearby drainage. The cuttings and water produced by the drilling operation would consist of only naturally occurring materials. If drilling conditions change, the possibility exists that a foam would be used to assist in removing the cuttings from the hole. Foams formulated for use in potable water wells would be used. The water production would be tested periodically during drilling to make an on-going assessment of the well's yield.
If the test wells do not become production wells, they will be capped and sealed to federal and state standards. Monitoring wells: One drilled to the top of bedrock (50-100') cased with 2in PVC pipe slotted at the bottom 2 ft of the well. This well would be drilled using a drill rig and placed as close as practicable to the stream along a line drawn perpendicular to the stream to the production well. This well would be fitted with a water level datalogging device.
One or two shallow(<25'), hand-augered or pounded drive point, wells immediately adjacent to the stream along the line described above. Wells would be cased with 1.5 inch steel pipe or 2 inch PVC. These wells would be fitted with water level datalogging devices.V-notch weir: A low flow v-notch weir (see attached diagram and photo) would be installed in Indian Creek. The weir would be installed with the minimum amount of concrete necessary to secure in place and seal the edges (note: there is no need to build the extensive structure pictured in attached photo). The weir would be sized to accommodate flows less than 1 cfs (450 gpm). Higher flows would simply pass over the top of the weir. The weir would be fitted with a 2 in PVC stilling well to accommodate a water level datalogger.
Background – To investigate the potential water supply options at Chinquapin for current and future area facilities, YI and the park propose to drill (up to) 2 test wells.