Amid mounting challenges to Colorado’s water supply, lawmakers are seeking to upgrade the decades-old method of tracking the state’s primary water source — snowpack. 

Since the mid-1960s, scientists have been measuring the amount of liquid water frozen within the state’s snowfields using snow telemetry, or SNOTEL, sites. Today, Colorado is home to 117 of these sites, which use pressure-sensitive pillows and sensors to gauge snowpack depth and water weight. 

The data is critical for water districts and providers to know how much water to allocate — and conserve — throughout runoff season. But the technology isn’t an exact science, and state leaders are looking for better ways for Colorado to accurately manage its water resources.

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Enter House Bill 1115, a bipartisan proposal from a group of Western Slope lawmakers that would create a new statewide snowpack measurement program using emerging tools like light detection and ranging technology, also known as lidar.

“This is a way for us to plan better in our storage facilities, in our reservoirs,” said House Speaker Julie McCluskie, a Dillon Democrat and a prime sponsor of the bill. 

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According to a May 2024 article from Colorado State University, nearly every long-term snowpack monitoring site in Colorado has seen a decline in snow water equivalent since the 1950s due to climate change, with some sites recording a decrease of nearly 80%. 

“Given the threats of drought and diminishing water resources in this state, it is incredibly important that we not miss a beat to lean in with innovative technologies, with more proactive thinking in addressing the threat to our water system and our water future,” McCluskie said. 

That’s where lidar comes in. 

Like radar, but using light, lidar sends beams from a plane or satellite towards the ground. By measuring the time it takes for the light to be reflected, scientists can calculate the depth of an area and create a 3-D model of the landscape. The flights also use a spectrometer to capture infrared images that show where snow is melting fastest. 

Glenwood Springs-based scientist Jeff Deems and his team pioneered the technology for snowpack mapping with the National Aeronautics and Space Administration in 2013. 

From those efforts, Deems co-founded Airborne Snow Observatories, a public benefit corporation that contracts with local and regional governments and water providers. Using a fleet of twin-engine planes equipped with lidar, the group runs flights to map river basins across the West.

Deems said lidar isn’t replacing SNOTEL, which remains the backbone for snow monitoring by providing a decades-long record of changes in snowpack. Instead, lidar is helping fill in the gaps. 

While SNOTEL sites pinpoint data at specific locations, lidar provides a full picture of the entire watershed. 

“The combination of the two gives us this really powerful 4D picture of a basin-wide snowpack,” Deems said. “We get the three dimensions from airborne surveys and the ‘time’ dimension from the SNOTELs, and that really gives us the best knowledge from which to anticipate and forecast our summer runoff.” 

Regional entities like Denver Water, Northern Water and the Colorado River Water Conservation District have contracted with Deems’ group in recent years to run lidar flights and create these multi-dimensional maps. 

“After a few years of investing in it, the level of specificity that it provides, especially as it relates to snow water equivalent above 9,500 feet, has been incredibly valuable,” said Lindsay DeFrates, spokesperson for the Colorado River Water Conservation District, which has allocated $500,000 to support lidar flights on the Western Slope over the next three years. 

House Bill 1115 would create a dedicated program for tools like lidar under the Colorado Department of Natural Resources’ water conservation board, allowing the state to contract for its own snowpack mapping services. 

Deems said it could lead to better coordination and streamlined support for local efforts while helping the technology become more widely available in Colorado. Lawmakers say it could revolutionize the state’s water management. 

“A real problem right now is we release probably way too much water than we should, earlier, and then we don’t have enough water in July and August in some places … and that’s the part that has really hurt our farmers and ranchers,” said Rep. Matt Soper, R-Delta, who is sponsoring the bill in the House alongside McCluskie. “This just allows us to more accurately make those predictions.” 

Better water management is a win-win for the state and its downstream neighbors, which are locked in negotiations over future use of the Colorado River. With new data influencing water allocation, the state can maximize its water contributions to the lower river basin states, Roper said. 

“We’re sending water down (to lakes Powell and Mead) and it’s sitting in basically what should be the savings account for the Colorado River,” Roper said. “And instead what’s happening is the high rate of evaporation means we’re losing credit for water we’ve already delivered for the lower basin.” 

By storing water longer at higher elevations in Colorado, Roper said the state can help mitigate how much is lost to evaporation when water is eventually released. 

But as the state looks to bring lidar in-house, lawmakers will be faced with funding questions for the program. Lidar flights can cost hundreds of thousands of dollars, and legislators remain cautious about bringing forward bills with a fiscal impact amid a tight budget year for the state.

House Bill 1115 wouldn’t approve new funding for lidar or other emerging technology. But it does allocate nearly $250,000 for the program for staffing and data systems over the next two fiscal years using existing dollars already earmarked for the water conservation board. 

McCluskie signaled the legislature could consider additional funding for the program, if created, in subsequent sessions. Lawmakers annually approve an omnibus bill to fund the water conservation board’s myriad projects. 

“I believe that we will need resources in the future as we expand this,” McCluskie said. “But I think those early conversations and moving in this direction we can do within existing resources.” 

Deems said once a state program is established, it could also open the door to new federal funding and eventually reduce the pressure on local and regional groups to foot the bill. 

House Bill 1115 is also being sponsored by Sen. Dylan Roberts, D-Frisco, and Sen. Marc Catlin, R-Montrose. It is scheduled for a House committee hearing on Feb. 20.