Casa del Agua and Desert House: Two Residential Demonstration-Research Projects on Water and Energy Efficiency

An Essay on a presentation made by Richard Brittain to Diwan al-Mimar on May 31, 2001

Prepared by Mohammad al-Asad and Majd Musa in association with Richard Brittain, 2002





 (1) Richard Brittain is an Assistant Research Professor in the School of Architecture at the University of Arizona. He teaches courses in desert architecture and architectural photography, as well as design-build studios. His private practice focuses on residential desert architecture, utilizing adobe and rammed earth wall materials, passive solar energy efficiency, and water conservation techniques with rainfall harvesting and graywater reuse systems. For additional information on Richard Brittain, see

 (2) The amount of rainfall in Amman ranges from 300 mm in the eastern parts of the city to about 500 in its western parts. The relationship between the two rainfall patterns, the unimodal of Amman and the Bimodal of Tucson, was discussed in a public lecture entitled "Creating Landscapes In Water-Scarce Environments: A Case Study Of Tucson, Arizona" presented by Margaret Livingston at Darat al-Funun in Amman in May, 30. For additional information on this subject, see the documentation of the lecture in the e-publications section of this web site.

 (3) For a complete list of the participants in the project, see note 7 below.

 (4) For more information on low-water-use plants and drip irrigation systems, see the documentation of Livingston's lecture, "Creating Landscapes in Water-Scarce Environments: A Case Study of Tucson, Arizona" in the e-publications section of this web site.

 (5) Harvested rainwater has been used historically for drinking and irrigation. With urban development, large centralized water supply systems have replaced individual water harvesting systems. However, people more recently have become reacquainted with water harvesting as an effective water conservation tool that provides free water independently from the municipal supply. Water harvesting also reduces off-site flooding and erosion by holding rainwater on site. In addition, passive water harvesting (which also is discussed in this essay) forces salts down and away from the root zone of plants, thus allowing for greater root growth.

For more information on rainwater harvesting, see Harvesting Rainwater for Landscape Use (Tucson: Arizona Department of Water Resources, 1999). This document is available online through the web site of the Water Wiser program of the American Water Works Association. The web site also includes a list of references related to the subject of rainwater harvesting and graywater reuse, as well as full texts of manuals and books on these subjects. In addition, the web site of the American Water Works Association provides downloadable publications relating to water harvesting.

 (6) See Glenn France, Evaluating the Effectiveness of a Community Water Conservation Demonstration / Education Project: Casa del Agua, Tucson, Arizona (Master's Thesis, University of Arizona, 1989).

 (7) For additional information on the Casa del Agua project, see Richard Brittain, K. James Cook, Kenneth Foster, Glenn France, Susan Hopf, and Martin Karpiscak, "Casa del Agua: Water Conservation Demonstration House - 1986 through 1998," Journal of the American Water Resources Association 37-5 (October 2001): 1237 - 1248.

 (8) For additional information on the Desert House project, see Richard Brittain, Kenneth Foster, and Martin Karpiscak, "Desert House: A Demonstration / Experimentation in Efficient Domestic Water and Energy Use," Water Resources Bulletin 30-2 (April 1994): 329 - 333.

 (9) The R-factor refers to "unit thermal resistance," which is the thickness of the element divided by the thermal conductivity of the material of which it is made.

 (10) An acre-foot is the volume of water that would cover one acre (about 4,000 square meters) to a depth of one foot (30.5 cm). This would amount to 1220 cubic meters.

 List of Figures*

Figure 1: A view of the Casa del Agua demonstration project in Tucson, Arizona.

Figure 2: A view of the backyard of Casa del Agua that shows the concrete paving and extended rooftop.

Figure 3: The installation of the underground rainwater storage tanks at Casa del Agua.

Figure 4: The landscaped area above the underground rainwater tanks at Casa del Agua: lawn area, Mesquite tree, and potted plants placed on the tanks' access manways.

Figure 5: The "hanging garden" at Casa del Agua: lettuce growing out of PVC pipes.

Figure 6: A view of the Desert House demonstration project and its surrounding context in the Desert Botanical Garden in Phoenix, Arizona.

Figure 7: The layout plan of Desert House.

Figure 8: A view of the ramada and adjacent vines installed at the south side of Desert House.

Figure 9: The technical exhibit at Desert House: the interactive computer.

Figure 10: The information center at Desert House: the model of Desert House and a simulation of the positions of the sun at the different times of the day and different times of the year.

 * All images are courtesy of Richard Brittain.


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