Simulating Streamflow Under a Warming Climate: Implications for Acequia Communities in the Upper Rio Grande

TitleSimulating Streamflow Under a Warming Climate: Implications for Acequia Communities in the Upper Rio Grande
Publication TypeConference Proceedings
Year of Conference2014
AuthorsSteele, Caitriana, Elias Emile, Rango Albert, Mejia John, and Fernald A.
Conference Name82nd Annual Western Snow Conference
Series TitleProceedings of the Western Snow Conference
Date Published2014
Conference LocationDurango, Colorado
Keywordsclimate change, irrigation, New Mexico, Streamflow simulation

Over the next century, it is predicted that warmer temperatures and altered precipitation patterns in the Upper Rio Grande (URG) basin will have a deleterious effect on the seasonal accumulation of snowpack and the timing and duration of snowmelt. In Northern New Mexico, acequia communities situated at the outlet of snowmelt basins are particularly exposed to climate-induced changes in snowmelt runoff. In this paper, we assess the variability in climate-affected streamflow of four tributaries of the Rio Grande. Each tributary is an important source of surface water for acequia communities. We used the Snowmelt Runoff Model (SRM) to simulate runoff from 4 sub-basins for years when the annual volume of water produced was above the median annual value (1984-2013). This exercise yielded basin-specific model parameters that could be then applied in SRM simulations of snowmelt runoff under altered climate conditions. For 60 CMIP-3 and CMIP-5 general circulation models we determined central tendency and spread of projected changes in precipitation and temperature at two locations, comparing the period 1980-1999 with 2040-2069 and 2080-2099. For simulations of streamflow under a changed climate, we used data from those models which best represented hotter-dryer (HD), warmer-dryer (WD), hotter-wetter (HW) and warmer-wetter (WW) conditions. Our results suggest that in agreement with other studies, annual volume of runoff is closely tied to changes in precipitation amount, while peak flow timing is affected by warming temperatures. If there is sufficient snow accumulation, increasing temperatures result in earlier occurrence of peak springtime flows. With insufficient snow accumulation, the characteristic snowmelt hydrograph is lost entirely. In a warmer climate with wetter conditions, springtime peak flows occur earlier in the year, are of shorter duration and are of greater volume than historic flows.