LIDAR GUIDED FIELD RECONNAISSANCE OF KARST FEATURES ON THE MOGOLLON RIM, COCONINO NATIONAL FOREST, SOUTHERN COLORADO PLATEAU

Karst terrains comprise 25% of the global land surface and are resource-rich areas of great importance to all lifeforms. A variety of resources occur within karst terrains including productive aquifers, abundant mineral deposits, and hydrocarbon reserves. Sinkholes, caves, and lava tubes provide shelter for rare flora and fauna, while preserving prehistoric material for centuries. Due to the fragility of karst terrains, they are vulnerable to many environmental impacts. Groundwater pollution and increased sedimentation rates represent adverse consequences of human activity in and around karst features. It is therefore necessary to protect karst terrains while preserving surrounding ecosystems and natural resources. Karst surveying commonly takes place in the subsurface within cave and aquifer systems. Thus, surficial observations are lacking and are a much needed component for connecting the subsurface with surficial karst processes.

To expand the knowledge of these surficial processes, this project focused on the rapid field inventory and assessment of karst terrain within the 64,000 acre Cragin Watershed Protection Project located on the Mogollon Rim District of the Coconino National Forest in Happy Jack, Arizona. Here, 15 Ma lava flows locally cap the expansive 250 Ma Kaibab Formation and both were found to contain abundant karst features. Using LiDAR and GPS, 286 potential karst feature sites were surveyed over a two month period. The inventory assessed 29% karst features and 38% pseudokarst features, with 31% being non-karst features. Of the karst features, 10% are emerging/sinking streams, 80% are sinkholes, and 10% are caves. Using ArcGIS Collector, data and photographs were acquired in-situ, uploaded to a shared database, and used within ArcMap to create a feature geodatabase. Resource protection buffers were designed for karst and pseudokarst features to offer protection from logging disturbance, preserve the microclimate and ecology of a feature, and prevent unnatural sedimentation rates that would destroy ecosystems and affect groundwater entering the 15,000 acre-feet C.C. Cragin Reservoir. Results suggest that within a 64,000 acre contributing area, a large number of karst and pseudokarst features play a significant role in the hydrologic system associated with the Cragin reservoir.