Groundwater recharge in desert playas: current rates and future effects of climate change

TitleGroundwater recharge in desert playas: current rates and future effects of climate change
Publication TypeJournal Article
Year of Publication2018
AuthorsMcKenna OP, Sala O.E
JournalEnvironmental Research Letters
Volume13 014025
Pagination10 pp.
Date Published01/2018
Accession NumberJRN00661
ARIS Log Number350016
Keywordsclimate change, desert playas, groundwater recharge, Jornada LTER, precipitation variability, runoff modeling, watershed ecology

Our results from playas, which are topographic low areas situated in closed-catchments in drylands, indicated that projected climate change in Southwestern USA would have a net positive impact over runon and groundwater recharge beneath playas. Expected increased precipitation variability can cause up to a 300% increase in annual groundwater recharge beneath playas. This increase will overshadow the effect of decreased precipitation amount that could cause up to a 50% decrease in recharge beneath playas. These changes could have a significant impact on groundwater and carbon storage. These results are important given that groundwater resources in Southwestern USA continue to decline due to human consumption outpacing natural recharge of aquifers. Here, we report on groundwater recharge rates ranging from less than 1 mm to greater than 25 mm per year beneath desert playas. Playas located in larger and steeper catchments with finer-textured soils had the highest rates of recharge. Vegetation cover had no effect on recharge beneath playas.We modeled catchment runoff generation and found that the amount of runon a playa receives annually strongly correlated to the rate of groundwater recharge beneath that playa. Runon occurred during precipitation events larger than 20 mm and increased linearly with events above that threshold.