Climatic modulation of water demand in the City of Albuquerque, New Mexico USA

David S. Gutzler1,2 Joshua S. Nims2

gutzler@unm.edu jnims@flash.net1Dept. of Earth & Planetary Sciences & 2Water 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

The ABQ City water supply now comes entirely from groundwater,so climate variability does not directly affect water supply

Albuquerque water consumption time series1

ac- f

t =

1.2

310

6 L

1994 consumption 925 L/d per capita2001 consumption 750 L/d per capita

USGS

Albuquerque basin / Rio Grande rift valley

Santa Fe group sediments

www.cabq.govonly the Upper Santa Fe group

is productive aquifer

1984 ad Albuquerque Living magazine

Water conservation: a recent concern in ABQ

Albuquerque aquifer: 1960-2002 declines

USGS

... 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 studyis the demonstration of a simple

algorithm to isolate the componentof municipal water use that is sensitive to climate variability

Does climate variability affect water use in Albuquerque?

Population certainly does!

over half of demand for City water is for residential use

Albuquerque water use by sector

summer season maximum

pronounced summertime interannual variability

Residential Consumption: Time Series by Month(data available only since 1980)

summermonths}

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

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)H2O consumption!

explained variance:

1981-1994: 65%1995-2001: 91%

regression modelworks better on independent data!

1 mm/d precip change 73 L/d consumption change 1 deg C Tmax change 15 L/d consumption change

Both precip and Tmax contribute to the regression P is the first order term

Possible effects ofconservation

1) H2O regression systematically over- estimates post-1995 data by 21 L/d per capita(a small bias!)

2) Improved fit to post-1995 data suggests thatpeople may be adjusting their H2O use to climatic conditions more carefully

• 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

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

2003 ad NOAA Climate Diagnostics Workshop

1984 ad Albuquerque Living magazine

Albuquerque?

Reno?

thanks for hosting us, Kelly!