1. Climatic modulation of water demand in the City of Albuquerque, New Mexico USA David S. Gutzler 1,2 Joshua S. Nims 2 gutzler@unm.edu jnims@flash.net 1 Dept. of Earth & Planetary Sciences & 2 Water Resources Program University of New Mexico, Albuquerque 1. Is there significant climatic modulation of water consumption? 2. Yes, if data are filtered to emphasize year-to-year changes in residential consumption in the summer season 3. Assessment of Albuquerque’s water conservation efforts supported by a grant from the NOAA RISA program

2. The ABQ City water supply now comes entirely from groundwater, so climate variability does not directly affect water supply Albuquerque water consumption time series 1 ac-ft = 1.23  10 6 L 1994 consumption  925 L/d per capita 2001 consumption  750 L/d per capita

3. USGS Albuquerque basin / Rio Grande rift valley Santa Fe group sediments

4. www.cabq.gov only the Upper Santa Fe group is productive aquifer 1984 ad Albuquerque Living magazine Water conservation: a recent concern in ABQ

5. Albuquerque aquifer: 1960-2002 declines USGS

6. ... we need to remove, or filter out, the huge effect of population growth before considering climatic effects (simply dividing by population doesn't work) The principal result of this study is the demonstration of a simple algorithm to isolate the component of municipal water use that is sensitive to climate variability Does climate variability affect water use in Albuquerque? Population certainly does!

7.  over half of demand for City water is for residential use Albuquerque water use by sector

8.  summer season maximum  pronounced summertime interannual variability Residential Consumption: Time Series by Month (data available only since 1980) summer months }

9. Population change is very steady (perhaps artificially so); looking at year-to-year changes in summer residential use is remarkably effective for isolating the sensitivity of total water consumption to climate variability Results to follow are based on JJAS residential use, 1980-2001; defining “summer” = JJA or JAS yields very similar results Summer climate and water use time series 2000, 2001 hot & dry; 2002/3 data continue this trend

10. Regression calculated on pre-conservation period (1981-1994), using 1995-2001 period as independent data Year-to-year changes in climate and summer residential water use are highly correlated this regression works equally well on total (instead of per capita) H 2 O consumption! explained variance: 1981-1994: 65% 1995-2001: 91% regression model works better on independent data!

11. 1 mm/d precip change  73 L/d consumption change 1 deg C Tmax change  15 L/d consumption change Both  precip and  T max contribute to the regression  P is the first order term Possible effects of conservation 1)  H 2 O regression systematically over- estimates post-1995 data by 21 L/d per capita (a small bias!) 2) Improved fit to post- 1995 data suggests that people may be adjusting their H 2 O use to climatic conditions more carefully

12. Climate variability matters for summer residential use Residential use >50% of total consumption Just under 50% of residential use occurs in summer Interannual variability is about +/- 15% of avg consumption Precip, Tmax anomalies account for most of this variance  examination of year-to year changes in consumption brings out the climate signal Explicit examination of the climatically sensitive component of water use can help assess conservation efforts Useful climate predictions would help water managers Climate affects maximum demand for water (in summer) Conclusions: Water Demand in ABQ

13. Short data record:...Would a major multi-year drought affect these statistics?...Long term effects of continued conservation efforts? Explicit inclusion of economic effects on consumption? Generalization to other cities in the SW US? Albuquerque’s water supply (100% groundwater) is now buffered from climate variability.... how does this affect consumption tendencies? Questions / Future Work

14. 2003 ad NOAA Climate Diagnostics Workshop 1984 ad Albuquerque Living magazine Albuquerque? Reno? thanks for hosting us, Kelly!