THE ROLE OF GROUNDWATER SAPPING ON LITTLE SPRING CREEK, GREAT SAND DUNES NATIONAL PARK AND PRESERVE, COLORADO, USA

The Great Sand Dunes National Park and Preserve (GRSA) is located in the San Luis Valley of southern Colorado, approximately thirty-seven miles northeast of Alamosa. The park hosts the tallest dune in North America and a complex aeolian system consisting of four major components: sabkha, sand sheet, dune field, and a sand ramp. A complete drainage system with headwaters originating above the dune field and to the east and a terminus located in the sabkha is a unique feature of GRSA. Because of non-consumptive ground and surface water rights associated with the park and the importance of water in this desert environment, the National Park Service is interested in understanding the hydrological processes affecting the dune field and meeting its obligation to protect the natural water levels necessary to maintain cultural, physical, and biological processes of the park.

Critical GRSA resources are gaining streams that emerge from the sand sheet and appear to be groundwater sapping systems. Few groundwater sapping studies have paid attention to the environment surrounding the groundwater sapping. Therefore, they neglect the important role groundwater sapping may play in channel incision and channel enlargement. In this study, a series of groundwater maps have been produced using well data, LiDAR, and precision surveying technology to gain an understanding of the environmental impact and importance groundwater sapping has at GRSA.