Town/City: 

Albuquerque

State/Province: 

New Mexico

Country: 

United States of America

Latitude/Longitude: 

35°06' 106°37'

Information supplied by

Christopher A. Houser

houser@scar.utoronto.ca

Scarborough College Coastal Research Group, 1265 Military Trail, Scarborough, Ontario, M1C 1A4

 (905)853-8456

Dated Wed Nov 17 21:14:29 1999

Information Topics:

City Description:

The City of Albuquerque was incorporated in 1885, shortly after the arrival of the railroad. Growth in the city was spurred during Wold War II and continued through the Cold War, by the Kirtland Air Force Base and various nuclear weapons facilities. The employment opportunities and the well-publicized quality of life lead to a steady population growth from 35,000 in 1940 to over 500,000 in the 1990's. In 1996, the population of Albuquerque was estimated to be over 670,000, with a growth rate of 13.7%, making it one of the 50 fastest growing cities in the United States. Today, Albuquerque is the regional centre of New Mexico, as is supported by various industry including tourism, and research institutes.

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Climate:

At an average elevation of 1800 m above sea level, the City of Albuquerque lies within a semiarid climatic zone. Temperature ranges from a low of 8 C in January to a high of 33 C in July. The average annual precipitation is 22 cm, of which 40% falls in the summer months during large storm events. However, the high summer temperatures, low relative humidity, abundant sunshine, and frequent wind result in large evaporation rates. Evaporation is estimated to be around 50 cm per year with a potential evaporation rate of 152 cm per year. As a result, the Albuquerque area regularly suffers drought conditions during the summer months, most recently in 1996.

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Basic Hydrogeology:

The hydrogeology of the Albuquerque area has been thoroughly documented by United States Geologic Survey (U.S.G.S.), as part of its Groundwater Atlas initiative (1995). The Rio Grande aquifer is the principal aquifer system in a 70,000-square-mile area of southern Colorado, central New Mexico, and Western Texas (Figure 1). The aquifer system consists of a network of hydraulically connected aquifers in intermountain basin-fill deposits, located along the Rio Grande Valley and nearby valleys. Groundwater flow is controlled by differences in water levels within the individual semi-enclosed basins, with a relatively small quantity of water flowing through narrow basin fill zones between the larger basins. The aquifer system in the Albuquerque area lies within the Albuquerque-Belen basin that forms part of the Rio Grande rift. The rift extends from Leadville, Colorado to Las Cruces, New Mexico. The rift is a northward-trending series of interconnected downfaulted and rotated blocks located between uplifted blocks to the east and west. In the Albuquerque, the rift has been filled with volcanic rocks and alluvium to a depth of 20,000 ft. The bedrock formations that bound the basin consist of Precambrian age granite, quartzite, schist, and gneiss, in addition to Paleozoic age marine deposits, volcanics, and clastic sedimentary rocks. Although some volcanic material, solution-altered carbonate rocks, and fractured beds can yeild water in local areas, the bedrock as a whole is considered to be an impermeable base to the aquifer system. Two geologic formations are the primary water-yielding material in the aquifer system, creating a complex series of unconfined and confined aquifers. The older Santa Fe group consists of unconsolidated to moderately consolidated lenticular deposits of gravel, sand, and clay, interbedded in some areas with andesitic and rhyolitic lava flows. The younger basin fill consists of interbedded quaternary gravel, sand, silt, and clay of fluvial origin in the Rio Grande valley. The younger basin fill material is similar in appearance and composition to the underlying older basin fill, from which it was derived, when the Rio Grande was entrenched by as much as 60 to 130 ft below the present floodplain. Thus, the contact between the older and younger units is approximately 100 ft below the present floodplain. Depth to water in the unconfined layer ranges from 0 (at the Rio Grande) to 100 ft below the land surface. Shomaker (1997) estimates that the unconfined aquifer system ranges up to 4500 m thick, and stores in excess of 1011 m3. In contrast the United States Geologic Survey (1993) found that the most productive zone of the aquifer system is much less extensive and thinner than was formerly assumed. It is predicted that the aquifer is only 1000 m thick. Transmissivities in the region South of the city have been estimated through pumping tests at 7400 m2/day (Thorn et al., 1993). Recharge to the aquifer system originates as precipitation in the surrounding mountainous areas. Runoff from rainfall or snowmelt flows a short distance before percolating through streambeds on the permeable alluvial fans. Some of the precipitation that falls on the mountains can supply water to bedrock aquifers that are formed by fractures or permeable layers in the material. The bedrock aquifers can discharge water directly to the basin-fill aquifer in the central valley along the mountain front, or discharge water to base-flow to mountain streams that recharge the basin-fill within the valley. Most of the precipitation that falls within the river valley is lost to evaporation and transpiration, with little water percolating to a depth sufficient to recharge the aquifer. Beds of relatively impermeable clay, silt, or unfractured volcanic rocks restrict the vertical movement of this groundwater to the unconfined layer. Within the Albuquerque basin groundwater flow is directed towards the river in the centre of the valley, induced by a groundwater level altitude difference of approximately 60 metres. However, groundwater withdrawal has lowered the water levels in the unconfined aquifer enough to reverse hydraulic gradients and induce additional recharge from the Rio Grande. Hansen (1995) estimates that 0.08*109 m3/yr of the Rio Grande streamflow now recharges the aquifer.

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Water Use:

Groundwater is currently the sole source of water supply for the City of Albuquerque, although surrounding irrigation projects extract water from surface supplies (NMWRRI, 1995). The city operates 93 water wells, distributed over 200 square miles, to a depth of 1,800 feet. In 1995, a total of 167*106 m3/yr was extracted from the groundwater supply, with a return flow to the aquifer of 80.4*106 m3/yr, for a total depletion of 86.6*106 m3/yr. Shomaker (1997) estimates that the demand for water will increase to 250*106 m3/yr by 2060. At present, the per capita water usage is one of the highest in the United States Southwest at 0.95 m3/day (City of Albuquerque, 1996). This high consumption rate is partly the result of Albuquerque having one of the lowest water-usage rates in the U.S. at $22.64 per 9000 gallons (34.2 m3), which are based on a service charge plus a flat rate per unit.

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Groundwater Issues:

As summarized by Smith (1989), rights to surface waters in New Mexico are regulated by a Doctrine of Prior Appropriation, and therefore, additional water use in Albuquerque is from groundwater. However, a close hydraulic connection between the river and the aquifer moderates water levels in both systems. Since the quantity of water in the Rio Grande is affected by groundwater abstraction, then developers of the groundwater supply must acquire sufficient water rights to offset the impacts of pumping. Until the early 1990's urban planning in the city was based on drawdown models developed in 1967 through the Theis equation (Thorn et al., 1993). Using this equation the City acquired sufficient pumping rights such that reclaimed wastewater would act as sufficient recharge to maintain the current level of the aquifer. However, the original model was based on assumptions of a homogeneous, isotropic, semi-infinite aquifer, with a fully-penetrating surface flow, and a perfect connection to the underlying aquifer (Thorn et al., 1993). These assumptions overestimated the recharge from the surface flow, and hence groundwater levels beneath the city started to drop more rapidly than expected. In order to offset the rapid decline in water levels, the city bought 59.4*106 m3/yr from the Colorado River system (Earp et al., 1998). Water is diverted from tributaries of the San Juan river and then rerouted to the Rio Grande. However, water levels continued to drop, leading to a reduction in the streamflow of the river. Although water rights to the Rio Grande are well entrenched, increased demand downstream in Texas, and Northern Mexico may lead to new arrangements. Considering the water demand in Ciudad Juarez, Mexico, which has a population base greater than the rest of the Rio Grande basin combined, changes in the allocation of surface water may lead to further restrictions on the water rights of cities upstream, including Albuquerque. The dewatering of the aquifer in the Albuquerque area has raised concerns about land subsidence. Shomaker (1997) using the work of Haneberg (1996) indicates that significant rates of subsidence would begin at a drawdown of 80 to 120 m. Haneberg (1997) states that groundwater levels in the city have dropped 50 m since the late 1960's. Using the current growth trend in water abstraction, the U.S.G.S. (1995), estimate that additional drawdown in parts of the city could reach 55 m by 2020. The primary concern is that land subsidence may cause similar damage to the city infrastructure as it has in Houston, Phoenix, the San Joaquin Valley, and El Paso (Haneberg, 1997). Concerns have also been raised about the quality of the groundwater supply (U.S.G.S., 1995). Turin et al. (1997) report that many of the highly productive wells along the river have been removed from service due to contamination from surrounding industry and naturally occurring arsenic in excess of the 50 ppb Environmental Protection Agency (EPA) standard. The EPA is considering changing the arsenic standards to a level between 2 and 20 ppb. Turin et al. (1997) report that it would cost the City of Albuquerque approximately $300 to $370 million to meet of standard of 5 ppb. Contamination of the groundwater supply is also occurring through the percolation of highly saline irrigation waters. Although no salinity data is presented for the Albuquerque area, infiltration of irrigation water has produced a minor saline zone (1000-3000 milligrams per litre of dissolved solids) between 100 to 150 feet thick in the Southern part of the aquifer system. The underlying freshwater zone extend to depths of 1000 to 1500 ft with a salinity of 300 to 500 feet thick. Another saline zone, with a salinity that exceeds 3000 milligrams per litre, is found in the unconfined portions of the aquifer. Dissolved solids in this zone are derived from the dissolution of calcite, gypsum, and halite in the basin fill and underlying bedrock. The salinity of this deeper groundwater source presents an economic barrier for its extraction.

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Groundwater Problems:

Although concerns over both the quantity and quality of the groundwater source in the Albuquerque area have been raised, action has only been taken with respect to the availability of the supply (Selby, pers comm). Since salinity limits extraction to the unconfined aquifer, the city can face serious economic and legal repercussions (through the Doctrine of Prior Appropriation) as a result of continued pumping of the limited resource.

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Solutions:

When the USGS (1993) raised concerns over the extent of the Albuquerque aquifer, there was a resulting change in management focus towards advocating water conservation (City of Albuquerque, 1996). The City of Albuquerque's Water Conservation Long-Term Strategy was adopted by the City Council in March, 1995. The management strategy partly involves an increase in water-use rates. In the summer, customer's that exceed 200% of their winter average are charged an additional surcharge of 21 cents/ft3. The average rate was also increased by 8.8 cents/ft3 to 65.8 cents per unit, with an additional 2.44 cent/ft3 surcharges. In conjunction with the increase in water rates, the city of Albuquerque has also implemented conservation programs for residential users. The program consists of voluntary and mandatory regulations:

Voluntary

Mandatory The city also requires that all municipal departments to develop and implement water reduction plans. As summarized by the City of Albuquerque (1997) these water management practices include:


The goal of this program is to reduce the 0.95m3 daily water use, (gpcd) between 1987 and 1993, by 30% to 0.66 m3 by 2004. Estimated savings through this program, derived through regression model analysis that takes weather and growth into account, is 70 million m3. In conjunction with this conservation program, the city has continued with its monitoring program in order to evaluate future water needs and the effects within the basin (City of Albuquerque, 1996).

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References and Other Author(s):

City of Albuquerque.  (1996)  Albuquerque's aquifer and how we meet the challenge.
City of Albuquerque Water Conservation Office. URL:  http://www.cabq.gov/resources/insert.html

Earp, D., Postlethwait, J., and Witherspoon, J. (1998) Albuquerque's environmental story. URL:  http://www.cabq.gov/aes/s5water.html/

Haneberg, W.C. (1997)  Bureau studies ground water pumping land subsidence. New
Mexico Tech. Homepage. URL:  http://www.nmt.edu/mainpage/news/haneberg.html/

New Mexico Water Resources Research Institute (1993)  Water Rates and Residential Conservation.  URL:  http://wrri.nmsu.edu/publish/dr/xvii/xvii-5.html/.

Shomaker, J.W. (1997)  Hydraulic conductivity across bedding planes: A critical control on conjunctive-use. In Groundwater in the Urban Environment: Problems, Processes, and Management.  Eds.  Chilton, J., Hiscock, K., Younger, P., Morris, B., Puri, S., Kirkpatrick, S.W., Nash, H., Armstrong, W., Aldous, P., Water, T., Tellman, J., Kimblin, R., and Hennings, S.  A.A. Balkema, Rotterdam.

Smith, Z.A.  (1989)  Groundwater in the west.  Academic Press, Inc, Toronto.

Turin, H.J., Gaume, A.N., Bitner, M.J., Hansen, H.S., and Titus, F.B. (1997) Albuquerque, New Mexico, USA : A sunbelt city rapidly outgrowing its aquifer.  In Groundwater in the Urban Environment: Problems, Processes, and Management.  Eds.  Chilton, J., Hiscock, K., Younger, P., Morris, B., Puri, S., Kirkpatrick, S.W., Nash, H., Armstrong, W., Aldous, P., Water, T., Tellman, J., Kimblin, R., and Hennings, S.  A.A. Balkema, Rotterdam.

United States Geologic Survey.  (1995)  Groundwater Atlas of the United States: Arizona, Colorado, New Mexico, Utah.  URL: http://wwwcap.er.usgs.gov/publicdocs/gwa/ch_c/index.html

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Contacts:

Dr. William C. Haneberg
New Mexico Bureau of Mines & Mineral Resources
2808 Central Avenue SE, Albuquerque NM 87106
(505) 262-2774

Andrew Selby
City of Albuquerque, Public Works Department
P.O. Box 1293, Albuquerque, New Mexico, 87103
(505) 768-3650

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