Water is arguably the most important resource in New Mexico. The recent ‘El Nino’ treated us well, bringing heavy rain last summer and snow during the winter. Does this mean that the drought is behind us?
Accessible climate data is remarkably difficult to find, buried in frustratingly complex websites such as www.nws.noaa.gov and www.wcc.nrcs.usda.gov. This blog entry is intended to introduce readers to useful data sources, with a principal focus on water resources. Only secondarily I offer a very general (and admittedly amateur) summary of the state’s recent climate history.
The best source of historical climate data is National Oceanic and Atmospheric Administration (NOAA), a division of the US Commerce Department. The site includes data from no fewer than 549 weather stations in New Mexico alone (though data is not complete for all stations.) Unfortunately, the data delivery is very cumbersome, data entry that makes one long for the Census Bureau’s Factfinder. We have grabbed and formatted data 1950- February 2016 for Albuquerque’s Sunport, which can be found here.
Average Monthly Temperature and Precipitation, 1950-2015, at Albuquerque International Airport
Source: U.S. Department of Commerce, National Oceanic & Atmospheric Administration, National Centers for Environmental Information. Station: ALBUQUERQUE INTERNATIONAL AIRPORT, NM US GHCND:USW00023050, Elev: 5310 ft. Lat: 35.042° N Lon: 106.616° W
Drought is a major concern in New Mexico. The University of Nebraska at Lincoln (UNL) employs a useful drought classification system to generate drought maps for the entire country. Classifications include None, Abnormally Dry, Moderate Drought, Severe Drought, Extreme Drought, and Exceptional Drought. UNL’s national drought maps can be found here: http://droughtmonitor.unl.edu/ and New Mexico maps can be found here: http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?NM
Here is the current map for the state:
New Mexico State University utilizes UNL data to provide an interesting time series chart of drought in New Mexico. http://weather2.nmsu.edu/drought/request/timeseries/. The chart shows the percentage of land in New Mexico by drought classification for 15 years.
The US Geological Survey (USGS) is the principal source of data on stream flow for the United States. USGS data, found at http://waterdata.usgs.gov/nm/nwis/rt updates stream flow activity in real time.
Finally, but perhaps most interesting, is a chart produced by the Texas Water Development Board, which has a strong invested interest in New Mexico’s water reserves. The chart shows acre-feet of water stored in Elephant Butte Reservoir going back 90 years.
What does all of this data tell us about New Mexico’s water situation? Compared to the period 2013-mid 2015, things look good. Less than three years ago, in summer of 2013, nearly all (98.7%) of New Mexico was in ‘Severe Drought’ and nearly half (44.9%) was in ‘Exceptional Drought’, the highest classification. Today, no part of the state is in ‘Severe Drought’ (though a dry February has moved some areas in ‘Abnormally Dry’.
But as the UNL drought maps (and NMSU’s time series chart) shows us, droughts come and go with remarkable frequency and periods of relative moisture can pass very quickly. Perhaps the most important story is the longer term trend. A millennial born in the early or mid-1980s is likely to have a skewed understanding of the state’s desert conditions. During the period 1984-2007, average precipitation in Albuquerque was nearly 10”, compared to less than 8” per year before and after. Put otherwise, only eleven times in the past 65 years has Albuquerque received more than 11” of rain; ten of those eleven times occurred during the 1984-2007 period. And don’t think that the next seven years, between 2008 and 2014, were especially dry. During that period Albuquerque averaged 7.5” of precipitation; during the period 1950-1956 Albuquerque received only an average of 5.4” of precipitation per year.
Finally, let’s look at what may appear to be small variations in precipitation mean for water supplies. Return to the Texas Water Development Agencies chart of water supplies in Elephant Butte. During the wetter years, the reservoir consistently held 2 million acre feet of water. But after only a few dry years, those supplies fell by more than 85%, to less than 250,000 acre feet.
Perhaps an easy (if overly general way) of understanding this data is like this: at current usage, if New Mexico receives 9 to 10 inches of precipitation, supplies remain relatively stable. But when precipitation falls much below that, supplies dry up quickly. And 9 or 10 inches of rain is not normal.
In addition to the sources described in this blog, visit the BBER Water Resources page for more information about New Mexico’s Water Resources.