Utilizing NASA TRMM Multisatellite Precipitation Analysis (TMPA) for Water Resource Management on the Navajo Reservation

The Four Corners Region of the southwestern United States is topographically complex and extremely arid, with a majority of the annual precipitation occurring during the summer monsoon season and in the winter months. The region is home to the Navajo Nation reservation that spans roughly 27,500 square miles of desert landscape in Northern Arizona, Southeastern Utah, and Northwestern New Mexico. Nearly 174,000 people live on the reservation where many families have no access to clean running water in their homes. Lack of infrastructure as a result of minimal economic resources confounded by environmental and climatic factors have limited access to a clean water supply for many Navajo. Access to water resources are critical for the Navajo’s energy-water-food nexus (EWFN) and economic sectors, including agriculture.

Currently, precipitation observations at the surface within Navajo reservation boundaries are sparse and radar coverage is insufficient. Limitations of the surface precipitation observations distributed throughout the Navajo Nation make hydrologic assessments for water resources difficult, especially in areas where radar coverage is not available. The use of space-borne precipitation observations is believed to provide the best spatial coverage for precipitation observations in the region. This research demonstrates, using NASA’s TRMM Multi-Satellite Precipitation Analysis (TMPA), that satellite-based rainfall estimates can be utilized in near real-time hydroclimate analysis for stakeholders in the Four Corners Region and for the Navajo Nation. With knowledge of the behavior of the TMPA product, especially on a monthly and seasonal basis, water resource managers in the region and on the Navajo reservation can have access to high-resolution precipitation observations in order to assess the condition of water resources as well as drought conditions.