eNews February 2017

Recipient of NM WRRI Student Water Research Grant Studying Effect of Tree Canopy Cover on Discharge of Upper Gallinas Watershed in New Mexico (continued)

The Gallinas River is a tributary of the Pecos River System in northern New Mexico, yielding an average of 3,100 acre-feet of water annually. The upper Gallinas watershed is located approximately 20 miles northwest of Las Vegas, NM and covers approximately 52,500 acres. Historical high resolution aerial photography of this region has been purchased from the Earth Data Analysis Center (EDAC). These images are available only in a non-georeferenced format. Therefore, a widely used image processing software system called ERDAS Imagine is being used to georeference the images so they can be used in other geographic information system programs. Another software package, eCognition Developer, is also being used to assist in the proper classification of image features.

Water discharge and precipitation data for the watershed have been obtained from a local gauging station and weather station near Las Vegas, NM. The tree canopy cover, water discharge, and precipitation data are being analyzed for possible correlations, and therefore possible cause and effect relationships, using a standard regression analysis software package (RStudio). Preliminary results concerning canopy coverage only suggest a sharp increase from the 1930s to 2014, likely due to reduced logging and grazing, fire suppression, and different land management practices over that time interval. It is expected that further analyses of this kind will lead to more useful insights to inform water management policies in the future.