In this case the appearance of this stream of water is cause for concern.An article in today’s Daily Sentinel reported:
… Tim Hayashi and Frank Kochevar Jr., respectively the senior engineer and survey supervisor for Mesa County, found the new stream as they visited the slide on Sunday, Hayashi said.
The discovery gave new urgency to the landslide study, Hayashi said.
“We’re at a point where Frank and I have gone from checking (on the slide) from once or twice a day to just about every hour,” Hayashi said. “And that’s ‘round the clock.”
The new stream rises about 75 feet above the base of the slump block — the large mass of mud, rock and debris still clinging to the side of Grand Mesa, Hayashi said.
Its appearance marks a “significant change” in the landslide and prompted heightened scrutiny of the slide according to an emergency action plan drawn up by the county for dealing with the slide. The plan accounts for three levels of response, of which the additional awareness is the first level.
There is no immediate threat to residents or to the town of Collbran, six miles to the northwest, Hayashi said.
Experts expected the stream to appear at some point, “it was just a matter of when,” Hayashi said.
The source of the stream is the lake, or sag pond, that has collected in the V-shaped area between the mesa and the slump block, Hayashi said.
“There is no other reasonable source of water” at this time, he said …
The cataclysmic event on the Grand Mesa which occurred on May 25, 2014, took the lives of Wes Hawkins, Clancy Nichols and his son Danny Nichols. The landslide created a mud and debris field 3 miles long and ¾ of a mile wide. What officials call a “sag pond” was formed from rainwater, snowmelt and other runoff near the top of the slide.The new stream of water that has recently appeared is about 75 feet above the base of what officials call the “slump block.”
Geologists, hydrologists, and other experts have been studying the area for the past year.
“We have been using different methods such as ground based photography, satellite imagery, and then field observations — hiking to the top looking for any new cracks, changes in water level, those types of things,” said U.S. Geological Survey Geologist Jeff Coe.
“We expected to see water-related changes in the Landslide during spring runoff,” said Tim Hayashi, Senior Engineer for Mesa County. “But one of the looming questions has been, ‘What would the pond do?’”
According the Emergency Action Plan drafted for the landslide, three levels of response can be initiated. Level Three is the highest alert level. At Level One there is no extra safety risk to citizens near the area.
The Town of Collbran is about six miles northwest of the landslide. Part of the mud and debris field covers property owned by the U.S. Forest Service; the remaining land belongs to private landowners. Because of the instability of the slide area, the U.S. Forest Service restricted area remains in place, including the landslide debris field and 300 yards from the edge of the debris field.
Mesa County, in conjunction with the U.S. Geological Survey, Colorado Geological Survey, U.S. Forest Service, Department of Parks and Wildlife and state officials continue to monitor the situation. Cameras, monitors and other devices are in place to alert officials of any movement. A new monitor has been placed about 100 feet above the new stream.
Mesa County’s emergency plan calls for immediate notification of the public when conditions become hazardous to citizens. Collbran residents have previously been briefed on the possibility of water spilling over the sag pond or finding a route down the debris area.