Some facts regarding the potential impacts of astronomy on Maunakea

It is important that we base comments and judgments on facts.

By Stephanie Nagata

Stephanie Nagata
Stephanie Nagata

Thirty Meter Telescope construction has stirred public debate over the impact that the TMT project and astronomy in general has on Maunakea. While the issues involved in these ongoing discussions are extremely broad, I think it is important that we at least base our comments and judgments on facts.

In this column, I would like to share a few true and verifiable statements drawn from reliable scientific sources and uncontested court testimony.


One of the often-raised issues is the supposed impact that astronomy activity has on the aquifer beneath the summit:

  • TMT and the Astronomy Precinct overlay the Waimea aquifer.
  • The aquifer is entirely fresh water and is isolated from other portions of the aquifer.
  • The Maunakea watershed is recharged at lower elevations where it rains, not in alpine deserts. Therefore, the main threats to Maunakea’s aquifer occur at lower elevations in areas of heavier population and use.


TMT will have no adverse impact on water quantity or quality:

  • Erosion is not a concern given the permeable lava flow substrate.
  • TMT will use zero-discharge wastewater systems (closed-system), meaning that all wastewater, cleaning solutions, etc., will be collected on-site and either reused or removed for proper disposal off Maunakea.
  • TMT mirror washing wastewater will not be a hazardous waste, but will be collected in double-contained pipes and tanks for disposal off the mountain.

Lake Waiau

There is no prospect of adverse impact to Lake Waiau, which lies roughly 1.5 miles south of the TMT site, and there will be no percolation of TMT wastewater to the aquifer:

  • Water levels in the lake respond to precipitation that occurs within the drainage basin, Pu‘uwaiau.
  • There is no surface water flow from any portion of the road or other infrastructure that reaches the lake.
  • No subsurface or groundwater from the Astronomy Precinct or road corridor reaches the lake.

Plants and Arthropods

Botanical surveys were conducted mountain-wide in 2011. This inventory found extremely low diversity and cover of vascular plants, mosses, and lichens. The individual species (and combinations of species) found during this survey are present both within the TMT site as well as throughout the high-elevation lava flow habitat.

Since 2012, the Office of Maunakea Management (OMKM) conducts annual monitoring of arthropods both at the TMT site and elsewhere.

  • There are no federally endangered, threatened, or candidate endangered species in the Astronomy Precinct or at the TMT site.
  • The TMT was deliberately sited away from wēkiu bug habitat. Wēkiu bug habitat is on cinder cones, while TMT is in lava flow habitat.
  • The wēkiu bug was removed as a “candidate species” by the U.S. Fish and Wildlife Service in October 2011 after conservation actions were implemented to help protect the bug.
  • OMKM continues to monitor wēkiu bug distribution and introduced species since 2002 and 2007, respectively.

While these conclusions cover just one aspect of the overall debate, I thought it was important enough of a subject to at least share these facts in the interest of clarity.

Stephanie Nagata is director of the Office of Maunakea Management.

This column was originally published in the May 2015 issue of the Hawai‘i Island Chamber of Commerce monthly newsletter.

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