The planned dismantling and removal of the Caltech Submillimeter Observatory from Maunakea has cleared another hurdle with the publication Wednesday of the final environmental assessment.
The document, approved by the state Department of Land and Natural Resources, found that the decommissioning project, which could begin as early as February, will cause no significant impact to the environment.
As outlined in the EA, Caltech intends to completely clear the CSO site — which sits on 1.3 acres within the MaunakeaScience Reserve — and restore it to its preconstruction condition, to the greatest extent possible. Infrastructure to be removed includes the observatory building, outbuilding, foundations, cesspool, utilities and grounding grid.
The project is expected to cost Caltech a little more than $4 million and should take a few months to complete.
Caltech will surrender its sublease to the University of Hawaii’s Center for Maunakea Stewardship upon completion of the project.
CSO is one of three Maunakea summit observatories to be decommissioned to make way for the planned eventual construction of the Thirty Meter Telescope.
The 10.4-meter, 43-ton CSO radio telescope saw its first light in 1986 and ceased operation on Sept. 8, 2015.
During a Sept. 28 public meeting on the CSO decommissioning conducted via Zoom, Jim Hayes, president of Planning Solutions Inc. — the consulting firm that prepared the EA — said the project will involve about 70 truckloads of material taken down from the mountain with about 36 vehicle trips a day throughout the project.
Hayes said an archaeological and cultural monitor vetted by the state Historic Preservation Division will be on hand to ensure the project doesn’t disturb any cultural sites.
According to Hayes, brief closures of Maunakea Access Road are expected in order to transport a crane up and down the mountain. Hayes said the closures will take place during off-peak hours to ensure as little disruption as possible.
Because the site is in a state conservation district, the project requires a Conservation District Use Permit from the Board of Land and Natural Resources. BLNR also is the entity that would grant right of entry for the dismantling of the observatory and restoration of the site.
Other permits and approvals required include: Historic Preservation Review by the state Historic Preservation Division; National Pollutant Discharge Elimination System permit from the state Department of Health Clean Water Branch; a state highways permit from the Department of Transportation; and construction and grading permits from the county Department of Public Works.
The EA can be viewed at https://bit.ly/3y83iqu.
Email John Burnett at jburnett@hawaiitribune-herald.com.
