SLVGO pushes ahead
on Sangre de Cristo Dark Sky Reserve
by Owen Woods
A 3,800-square-mile area of the San Luis Valley, Wet Mountain Valley, and Huerfano County is in the process of being designated as a dark sky reserve. If approved, it would make it the largest dark sky reserve in the world.
San Luis Valley Great Outdoors (SLVGO) is spearheading the project and plans to submit a completed application to the International Dark-Sky Association by 2022. The designation would bring with it a wealth of environmental, human health and economic benefits, as well as an overall reduction of light pollution, according to the International Dark-Sky Association. Reducing light pollution can in turn mitigate the health and environmental damage that it has caused so far. Advocates of the dark-sky reserve hope to help the Valley navigate the process and demonstrate how light pollution can be sustainably managed in the future.
The Citizen sat down with Dani Gronhovd, the community connections coordinator for SLVGO, to better understand how a dark sky is measured, what the communities within this proposed dark sky region can expect from a dark sky designation, and what kind of local government ordinances are required for the application. Gronhovd has been working with communities throughout the San Luis Valley, in the Wet Mountain Valley communities of Westcliffe and Silvercliff, and Walsenburg and La Veta in Huerfano County to reach out and educate the public on the process of becoming a dark sky reserve.
The core area of the proposed reserve is in the Sangre de Cristo Wilderness Area. According to the USDA, the SDC Wilderness Area covers 220,803 acres, which is just 345 square miles of the proposed 3,800-square-mile dark sky reserve.
DARK SKY READINGS
As part of the application process, dark sky readings must be conducted. “The core is the Sangre de Cristo Wilderness Area and the Great Sand Dunes,” Gronhovd explained. A group of volunteers has been conducting tests monthly since the summer of 2019, in every part of the proposed reserve area – as far south as the state line and as far north as the Orient Land Trust. “We go to the same locations over and over again.”
Different parts of the proposed reserve area can provide different readings. And seasonal and time fluctuations can occur that can cause a wide range of readings. “We just try to take as many readings as we can so we can even out that curve, that variability.”
The tests are conducted with a device called an SQM, or Sky Quality Meter, that measures sky brightness in astronomer units, which is magnitudes per square arcsecond.
“It’s a strange measurement,” Gronhovd said. The higher the number, the darker the sky. The IDA requires an average measurement of 21.2 magnitudes per square arcsecond. “We consistently get around 21 to 22. It’s consistently dark in the region. There’s a minimum standard you have to reach for sky quality. And we’re definitely there.”
The readings are a small but vital part of the application process. The wildfire smoke the Valley has been enduring this summer has thrown off readings, but the IDA understands that these natural disasters will affect the night skies, and Gronhovd feels hopeful the smoke will not hinder the application.
The most important aspect of the application process is community support and engagement, and agreement from local governments. “We need that support from the community to be designated as a dark sky reserve,” Gronhovd said.
Within the reserve area, 80 percent of the population and 80 percent of the designated land area need to adopt the Lighting Management Plan. If the application is approved by IDA, the municipalities in the reserve will have to adopt outdoor lighting ordinances. These ordinances are the main point of contention among local governments.
“There’s a lot of mixed reviews … The kind of overall reaction that I get is that people are very interested. They’re very interested, but don’t know whether or not they should dive into it now and say, ‘Yes, we’re gonna adopt this lighting management plan and be a part of your effort.’ Or they might just want to step back and see how it goes, ‘see what other counties and what other municipalities do and let’s see what kind of benefits they reap from this initiative…’” Gronhovd said.
A challenge some communities face is simply size. Workforce and funding affect how outdoor lighting ordinances are enforced. With limited – or no – code enforcement, the entire effort is hindered. “And, ultimately, peer pressure from neighbors to preserve dark night skies is far more effective than any ordinance,” Kairina Danforth, mayor of Crestone, told the Denver Post.
“Typically, lighting is a complaint-based issue,” said Grovhovd. Light trespass has become a point of discussion. With a dark sky approval, code enforcement can enact light management just as they do noxious weed management. Code enforcement does have the Lighting Management Plan as a reference guide. There are also municipality-wide changes that would go into effect with an approved reserve. For example, for every 5,000 residents, 10 night-sky friendly lighting fixtures would have to be installed. The minimum requirements for reserves are extensive, and you’re encouraged to read them here.
In the Lighting Management Plan, there are 5 minimum provisions:
- That outdoor lighting conforms to local and national laws.
- That outdoor light is used only when absolutely necessary, in an appropriate amount, and used strictly to ensure public safety.
- Outdoor lights that give off more than 500 lumens must be fully shielded (“fully shielded is defined as such that the light source is screened and its light directed in such a way that none is emitted above the horizontal plane passing through the lowest light-emitting portion of a fixture”). Lights that give off less than 500 lumens may be unshielded for different purposes, such as historical preservation. The Dark-Sky Association require light fixtures to be redesigned to lower impact on the night sky. Motion-activated sensor lights that have less than five minutes of illumination after activation are exempt from the Lighting Management Plan.
- Short-wavelength light emissions have to be minimized, and will have to be restricted to lamps not exceeding 3000 Kelvins, or light that must not emit more than 25% of its total power, or scotopic-to-photopic ratio that must not exceed 1.3.
- Visitor, or tourist, lighting has to be regulated. Camping and recreational vehicles have to limit their light emissions, inappropriate “light painting” and unnecessary use of searchlights has to be outlawed. A key aspect of this is that visitor safety must not be compromised.
The specifics of these requirements may seem to bog down implementation of the ordinances and make them appear to be more complicated than they really are. The point of a positive community outreach and engagement is to educate the public on the benefits of a dark sky that goes far beyond ordinances. The laws are a minor piece to a major puzzle – the great beyond.
WHY IT MATTERS
Dark skies don’t just benefit migratory birds and wildlife – dark skies are important to human health. According to studies from the American Medical Association, Harvard Medical School, and an extensive study published by Environmental Health Perspectives, light pollution is associated with an increase in cancers, obesity, diabetes, and sleep and mental health disorders. The American Light At Night (ALAN) Database has compiled articles and studies of the effects of light pollution on everything from animals to humans.
Eighty percent of Americans, according to a 2016 study, can’t see the Milky Way. Life has moved so quickly in the past few hundred years, that we often forget to look up. The wonder of the stars has transgressed time itself. Efforts like the Sangre de Cristo Dark Sky Reserve may inconvenience us today, but think of how we may feel tomorrow when the stars look just a little brighter.
Hopeful, Gronhovd said, “We’re just trying to mitigate light pollution, keep our skies dark, and make sure we’re using our lighting in a responsible manner.”
Night sky photo courtesy Great Sand Dunes National Park and Preserve