Bathymetric LIDAR pilot shows high-resolution nearshore detail but limited penetration; UGS seeks $1.8 million for expanded mapping

Mike Vandenberg, head of the Energy Minerals program at the Utah Geological Survey (UGS), presented results from a June 2023 bathymetric LIDAR pilot funded in part by the Great Salt Lake Advisory Council and UGS.

The pilot covered roughly 50 square miles on the west side of Bridger Bay and was contracted to NV5 Geospatial. Vandenberg said processing took several months and the pilot yielded high-resolution nearshore bathymetry where the green laser could reach the bottom, producing vertical resolution on the order of 0.2 meters. In those areas the dataset revealed features such as microbialite domes and previously unmapped meter-scale mounds that may indicate groundwater discharge under the lake.

But the pilot also met important limitations. "So overall, we got data only on 28% of this area that we shared. So we spent a $100,000 and only got 28% of the data," Vandenberg said, noting that turbidity, transient surface conditions and water depth limited penetration of the green laser to approximately 14 feet of water in the best locations. The pilot also showed unexplained voids in otherwise shallow shelf areas where returns were absent; the team is investigating whether those gaps were ephemeral (foam, slicks, waves) or caused by other factors.

Vandenberg said the State approved $1.8 million in one-time funds from the Forest Fire State Lands restricted account to support a broader bathymetric LIDAR effort. UGS has issued a solicitation to several qualified vendors and is holding follow-up meetings; the procurement will target prioritized nearshore bands rather than deep-center areas where pilot results suggest the method is unlikely to return bottom data.

Vandenberg recommended continued pilot work in wetlands, ponded shallow zones, and Farmington/Bear River Bay to test methodology before committing to larger-area flights. He invited attendees to review a poster of pilot results and to provide feedback on priorities and the vendor selection process.