Paleoenvironmental research applied to a water rights battle at the Monte Vista National Wildlife Refuge, Colorado, USA

Keywords: environmental, geomorphology, wetland, water, Colorado, wildlife
Session Type: Virtual Guided Poster
Day: Thursday
Session Start / End Time: 4/8/2021 04:40 PM (Pacific Time (US & Canada)) - 4/8/2021 05:55 PM (Pacific Time (US & Canada))
Room: Virtual 53

Abstract

Natural wetlands and springs have dried out on the Monte Vista National Wildlife Refuge (MVNWR) in southern Colorado. Spring creek is a small, artesian fed creek that previously ran through the MVNWR. The Refuge lost their Spring Creek water rights because Alamosa Water Courts argue that wetland recharge in this area is from the Monte Vista Canal (MVC) built in the 1880’s to divert Rio Grande water for agriculture. Natural and social science methodologies were used to ascertain whether the original source of these wetlands is Spring Creek as the MVNWR asserts, or the MVC as the Alamosa Water Courts suggest. Methods include analysis of historical maps and land ownership documents, carbon 14 dating of wetland peat, dendrochronology of an associated juniper grove, and isotopic analyses of δ2H and δ18O on tree cellulose, MVC water, and groundwater. Important historical documents include an 1873 Wheeler Expedition map showing a flowing creek and marsh/wetlands around Spring Creek in 1877, before the MVC existed. Based on thirteen carbon 14 ages from peat samples in a paleowetland at the locality, the water table was higher and standing water was present before the MVC installation. Isotopic analyses of the groundwater and MVC waters show isotopic differentiation. An isotopic analysis of a tree core from the associated Juniper grove is in progress and may show whether the grove was established with groundwater or MVC water. Dendrochronology data suggest the grove was established before 1870, supporting evidence that Spring Creek was active before the MVC was constructed.