Solar Power Shines

Alameda County is reducing CO2 emissions by 1,000+ tons per year. It is one of the nation’s earliest proving grounds for the U.S.’s fastest growing renewable energy technology.

No other county in the U.S. better exemplifies the thoughtful and ambitious deployment of solar power than Alameda County.

Alameda County has been at the forefront when it comes to using solar power — and demonstrates continued leadership in this arena. At the county level, Alameda is the nation’s largest deployer of solar power, with a total of 3.0 MW of solar photovoltaics (PV) commissioned at nine County-owned facilities.

Alameda County was keen to deploy smart energy strategies — integrating solar generation and energy efficiency measures into county-owned and operated facilities. For years, the County has been a leader in smart energy investments; this is a direct result of the vision and leadership of the County’s Board of Supervisors and General Services Agency to reduce the County’s annual overall energy usage and costs.

A number of cost-effective energy efficiency programs were launched in 1993, when the County’s General Services Agency hired its Energy Program Manager, Matt Muniz, P.E. One of Muniz’s first projects was to retrofit over 12,000 fluorescent light fixtures with energy efficient T-8 lamps and electronic ballasts and install innovative lighting controls throughout the County’s Santa Rita County Jail in Dublin, CA. Later Mr. Muniz’s energy team replaced over 550 inefficient fractional horsepower exhaust fan motors with premium efficiency motors at a payback of less than one year. Both of these projects are part of Pacific Gas & Electric’s (PG&E) “PowerSaving Partners” demand-side management program. As a PowerSaving Partner, the County has received over $3.2 million in direct incentive payments and ultimately reduced electricity costs at its Santa Rita Jail by one-third.

Charged with the task of achieving even greater energy savings at other Alameda County facilities, Mr. Muniz and his energy program colleagues implemented a number of other energy efficiency measures that presently total over $4 million in annual cost avoidance savings. These measures included lighting retrofits in 95% of County owned-buildings, the installation of state-of-the-art building automation systems in 25 facilities, replacement of most chillers with energy efficient and CFC-friendly equipment, and installation of Variable Frequency Drives to the HVAC systems in County facilities.

In early 2000, the City of Oakland was evaluating ‘green’ electricity purchase options and met with executives of PowerLight Corporation, a subsidiary of SunPower Corporation. PowerLight’s protective insulating solar electric rooftop technology gave them a new demand reduction challenge: How could he and his colleagues continue to reduce energy costs at the Santa Rita Jail by generating electricity from an onsite solar power plant?

“I thought that we had completed all the cost-effective energy saving measures that were possible at the jail,” said Matt Muniz, P.E., Alameda County’s Energy Program Manager. “But with over a half-million square feet of unused flat roof space at the jail and the recent drop in prices for solar cells I immediately concluded that solar electricity was the perfect solution for further demand reduction.”

How could Alameda County achieve its vision of becoming a leader in solar energy? Could the economics of large-scale solar PV pencil out? How would such a large capital purchase be financed?

The answers to these questions began with the abundant solar electric incentive programs available in California — the predecessors to today’s statewide California Solar Initiative program — that made the solar electric system affordable in its own right. However, an even more affordable idea was devised: to combine on-site solar electric generation with reductions in the jail’s overall energy use by implementing energy efficiency and sophisticated energy management measures.

Soon thereafter PowerLight Corporation contracted with its strategic partner, CMS Viron Energy Services (which was acquired in 2003 by Chevron Energy Solutions), to showcase the synergy between the latest advancements in solar PV and state-of-the-art energy efficiency technology.

Alameda County, PowerLight, and Viron then crafted an integrated solar electric generation and energy efficiency plan with the goal of exceeding the County’s 10% internal rate of return threshold for energy projects. It would soon serve as a model for other local governments and large commercial customers concerned about rising electricity rates, reliability, and the nation’s increasing reliance upon polluting sources to supply electricity.

The Santa Rita Jail offers proof that solar and energy efficiency are a synergistic blend of technological innovations well suited to respond to today’s stressed power grid in California. By linking the largest rooftop solar PV system in the U.S. explicitly with energy efficiency upgrades and state-of-the-art energy management software, Alameda County is able to reduce its peak power consumption, without any expenditure from its general fund. Some of the innovations that make the Santa Rita Jail project noteworthy include:

Solar Power Installation Provides Multiple Benefits:
PowerGuard® tiles incorporate state-of-the-art solar cells backed with insulating polystyrene foam, turning the sun’s free energy into usable power while increasing building thermal insulation and extending roof life. A key innovation of these roof tiles is that they can be installed on flat rooftops without penetrating the roof membrane.

Applying a “Cool Roof” Membrane with High Solar Reflectivity:
By applying a “Cool Roof” reflective coating on the jail’s existing roof, the roof area not covered by solar tiles now reflects 65% of the solar energy. This effectively reduces the roof’s temperature during the hot summer months by 50 degrees Fahrenheit. Peak electrical demand reductions result from the reduced air conditioning requirement in the occupied spaces below.

Replacing Inefficient Equipment Generates Large Electricity Savings:
Large electricity savings are garnered by replacing an old inefficient chiller with a new 850-ton high efficiency chiller that does not use CFCs that contribute to the degradation of the ozone layer. New variable speed drives attached to the new chiller, chilled water pumps, and cooling towers will respond directly to the precise real-time cooling requirements needed to deliver chilled water instead of operating at 100% speed all of the time.

Smart Energy Management Optimizes Overall System:
Implementation of Utility Vision™, a computerized energy management system developed by CMS Viron automatically reduces peak power consumption during dips in solar power generation. These dips may be caused by normal weather conditions such as cloud cover. For example, if clouds block the sun for five minutes on a summer afternoon, Utility Vision automatically reduces power consumption proportionately so that no additional purchases of expensive peak priced electricity are necessary.

Following the installation of the solar system at the Santa Rita Jail Alameda County was so pleased that it decided to add an additional 1.8 MW of clean solar power into its energy mix. Several more solar arrays were installed at the following County venues between 2003 and 2007 — the Office of Emergency Services, the Environmental Health Services, the Winton Avenue Government Building, the Wiley W. Manuel Courthouse, Hayward Public Works, Fremont Hall of Justice, and the new Juvenile Justice Center.

Alameda County’s deployment of solar power has played an enormous role in bringing down utility costs. By integrating solar power generation with energy efficiency measures, Alameda County has demonstrated enormous leadership in defining both clean and cost-efficient energy solutions. The County’s cumulative 3.0 MW of solar power systems generate 4 million kilowatt-hours of electricity annually, much of it produced during peak demand times, when the utility grid is the most strained and electricity is most expensive.

Overall, Alameda County’s solar energy investments are enabling the County to meet eight percent of its electrical needs at its facilities with clean, renewable solar power. Its grid-connected solar systems help reduce the County’s electrical demand; consequently, it saves over $500,000 annually in avoided electricity purchases. These savings add to the $3.5 million annual savings associated with its energy efficiency measures.

The environmental benefits of Alameda County’s deployment of solar power and other energy efficiency improvements are considerable. Over the next 30 years, the environment will be spared from thousands of tons of air emissions such as nitrogen oxides, sulfur dioxide and carbon dioxide. These emissions are to blame for our urban smog, a primary cause of asthma and other respiratory diseases and contribute to global warming. And over that same 30 years, the solar-generated electricity will reduce carbon dioxide emissions by 45,000 tons. These environmental savings are the equivalent to planting over 270 acres of trees or avoiding driving 71 million miles on California’s roadways.

Energy performance data is posted on the internet so that Alameda County, governmental agencies, solar customers and other interested parties can review and analyze the performance of Alameda County’s solar installations and the energy efficiency measures.

Alameda County has shown that large-scale solar systems can indeed be cost effective investments and even more cost effective if the system is integrated with the facility’s energy management infrastructure.

The solutions offered by effective deployment of solar power reflect the future of the energy industry and point the way toward stable power costs and pollution-free, local energy choices. As volatility in energy pricing continues, increasingly the public and private sector will follow Alameda County’s visionary lead.

The Impact of Energy Consumption on the Environment

What is the Biggest Culprit? Concerns about the impact of energy consumption on the environment, especially global climate change, have finally penetrated public consciousness to the point where significant political action is beginning to happen.

USEnergy3 copyAny number of events can be cited as triggering this step change in consciousness. Al Gore’s movie An Inconvenient Truth, numerous cover articles by our leading weekly magazines, a continuous stream of newspaper articles, scientific reports from prestigious committees, appeals to the President by business leaders, politicians, and scientists, etc., have outlined the risks and challenges to the planet in compelling detail. As Governor Arnold Schwarzenegger commented when he introduced Executive Order S305 on greenhouse gas reduction, “I say the debate is over. We know the science. We see the threat. And we know the time for action is now.”

The question is: where should we focus our efforts? We can begin by asking: where are the biggest culprits and what are the most immediate cost effective strategies, but the challenge is more fundamental than the idea of mitigation or conservation, as important as they are. Ultimately, we must rethink and convert our 200-year-old fossil fuel economy to renewable sources. An even more fundamental question is: can we do it in time to avoid catastrophic change and human hardship?

The recent announcement at UC Berkeley of a $500 million grant by oil giant British Petroleum (BP) to develop biofuels is not only by far the largest alliance between industry and the academies, but also the kind of investment and vision necessary to bring renewable energy swiftly to market. BP’s grant will fund hundreds of researchers in 25 teams, 18 at UC Berkeley and Lawrence Berkeley National Laboratory (LBNL) and 7 at University of Illinois Urbana-Champaign, while BP will assign up to 50 of its own researchers to join the teams. The potential of this landmark interdisciplinary effort is planetary. LBNL Director Steve Chu has estimated that if the acreage which American farmers are currently subsidized not to cultivate were planted in “switch grass” and if ethanol from this cellulose source could be brought to market at the efficiencies demonstrated in the lab, it could provide as much as 100% of the country’s transportation fuel needs. UC Berkeley Chancellor Robert Birgeneau has characterized the effort as “our generation’s moon shot.” Charles Zukoski, Vice Chancellor of Research at the University of Illinois Urbana-Champaign, described it as launching “a new age for agriculture, altering the energy economy of the planet.” As essential and groundbreaking as this effort is, how big an impact will it have on the problem?

World Energy Supply Bar GraphAn examination of our energy consumption by broad sectors reveals the following approximate breakdown: 27% transportation, 30% industrial, 22% commercial, 21% residential. Almost all the energy consumed (90%) comes from fossil fuels, with the remainder from nuclear and renewables, including wind and hydro. When each sector is examined in greater detail, some surprising facts are revealed. Within the transportation sector, only 16% is consumed by cars and trucks, the remaining 7% goes to trains and planes. Thus, if all the transportation fuel for cars and trucks (as big a number at that is) were converted to biofuels, it would still only address 16% of the problem. So what is the biggest culprit?

As Ed Mazria has pointed out in his “2030 Challenge” to design and construction professionals, if you add up the residential and commercial sectors with the portion of the industrial sector consumed by buildings, it totals 48% of the total energy consumption! If you look at electric consumption by itself, 75% goes to operate buildings. With the projected increase in electrical demand planned to be met by coal-fired power plants, the impact of buildings is even more important. Quite simply, buildings are both the biggest problem and opportunity.

Mazria also points out that over the next 30+ years, we will build approximately half again as much new square footage as already exists and we will renovate about 50% of the existing square footage. This means that in the year 2035, three quarters of the built environment in the U.S. will be either new or renovated. This gives design and construction professionals the largest responsibility for making a real difference, but as Schwarzenegger has said “the time for action is now.”

We know from over 30 years of research and development since the last oil crisis in the early 1970s, that we can reduce the energy consumption in buildings by 50-70% through intelligent conservation and the application of passive solar heating, natural ventilation and careful daylighting. The question becomes how do we get the rest of the way to zero carbon buildings — i.e., buildings which generate all of their energy needs from renewables. This is the “moon shot” challenge to design and construction professionals.

With the loads for heating, cooling and lighting reduced dramatically by the strategies above, the remaining challenge is the electric loads for building equipment, appliances and especially the so-called “plug loads” for computers, televisions, kitchen and office equipment. Conservation in lighting and appliances, especially refrigerators, are the reason why electric consumption in California has been flat for the last 20 years in spite of population growth. This phenomenon has been called the “Art Rosenfeld Effect” because he pioneered the “energy star” rating system for all appliances, especially refrigerators. Natural competition in the market place, as a result, reduced energy consumption by 50%. His colleagues at LBNL pioneered in the development of high efficiency light bulbs with a similar result.kyoto

To achieve the goal of zero carbon buildings, the country will need the next generation in conservation technologies in all areas of electric usage, including lighting, appliances, televisions, computers, etc. Fortunately, many of these technologies are in the development phases and are on the way. As demonstrated in California by the “Rosenfeld Effect”, conservation will remain the single most cost effective first step. Nonetheless, buildings will still require electric power; even with reduced loads, and the challenge is can it be met by renewables?

Through our research at the college on the application of photovoltaics and wind technologies to buildings, we have discovered recent commercially available breakthroughs which are extremely promising. By integrating photovoltaics (PV) directly into building assemblies, like roofs and curtain walls, i.e., substituting existing materials with PV materials, the cost effectiveness of PV is already competitive in some markets, especially when compared with peak power. When the next generation of efficiency achieved in the lab (20%-40%) is brought to market in 3-5 years, the integration of PV into building assemblies should become a matter of course for designers.

The story about the integration of small-scale wind machines into building design is equally promising. A new generation of vertical axis machines, double-helix spiral-like rotors, seems to have solved many of the prior problems. Quiet, non-vibrating, effective at low speeds and multi-directional, their applications on roofs and facades offers multiple design opportunities.

When both of these technologies are combined, we have discovered that they have the potential of providing more than 100% of the total electric loads, on an annual average basis, after careful conservation. Yet, the final challenge is overcoming the intermittent timing of these renewables. What do you do if there is no sun and no wind, and you are unable to capture excess energy (when available) by running the meter backwards, i.e., using the grid as storage?

The final step to zero carbon buildings, for instance providing the backup to wind and solar, comes from a surprising source — the waste streams. In our research work on sustainable neighborhoods in China, we have discovered that food wastes, the sludge from primary sewage treatment and green wastes from the landscape, urban gardening and agriculture together generate a significant energy resource in the form of biomass. New technological breakthroughs in biogas generation use a two-stage anaerobic process to convert as much as 80% of the potential energy in the biomass into biogas — methane and hydrogen. This energy source can be put to many uses, for example: providing gas for cooking, compressed gas for gas-powered vehicles, or powering gas-electric turbines for the base or back-up electric loads.

solarFor this technology to be cost effective, however, it needs a minimum flow of biomass material equal to about 8-10 tons per day, or the waste created by a mixed-use, high density neighborhood of approximately 5,000 units of housing (15,000 people). While the construction of such a neighborhood is the exception in the U.S., 10-15 of these kinds of neighborhoods are completed every day in China. We have discovered that the three renewable energy sources, wind, solar and biomass together can provide all the energy for such a neighborhood. Indeed, the neighborhood can be a significant energy exporter to the grid — especially at peak demand during summer afternoons. The challenge of realizing such an integrated and self-sustaining system of energy supply is that it requires a whole new way of doing business for the design and construction industry. The developer, architect, landscape architect, civil engineer, mechanical engineer, city departments of planning and public works, have to operate under a whole new paradigm of collaboration and integration. But the rewards are planetary; zero carbon neighborhoods could become a reality.

In the end, the goal of achieving a carbon neutral future in the building sector is at least several years off, at the building scale. It will take multiple technology breakthroughs in all areas of energy conservation and renewables before the building will be an appropriate scale for supplying all of its own energy needs. On the other hand, a carbon neutral future is already achievable at the neighborhood scale. The question is: will planning, design and construction professionals seize the opportunity?

At CED we are striving to provide the educational foundation for our students which will prepare them to seize a leadership role in this effort. UC Berkeley tops a short list of institutions with the unique combination of breadth and depth needed to develop innovative design solutions and approaches to public policy. It requires not only the collaboration of multiple faculty in our three disciplines, but also reaching across campus to civil engineering, the energy and resources group and anthropology, listed below. CED is the only school in the country where this new paradigm has a chance of being realized and is exemplified by:

  • Elizabeth Deakin and Robert Cervario’s work in transit-oriented development and the making of walkable and bikeable cities with Michael Southworth
  • Tim Duane and Randy Hester’s work to reconcile competing demands on the ecosystem on the island of Hawaii
  • Judith Stilgenbauer’s work on green infrastrutures — the multi-functional and productive features of landscape
  • Galen Cranz’s examination of the social and cultural bases of a sustainable lifestyle
  • Our building science faculty – Cris Benton, Gail Brager, Ed Arens, and Susan Ubbelohde — work on energy conservation, daylighting, lighting controls, interfloor mechanized systems, dual mode buildings and user response to environmental quality
  • Our collaboration with The Berkeley Institute of the Environment (BIE) and Energy Resources Group (ERG) faculty – Inez Fung, Dan Kammen, et.al — on renewable energy systems, solar, wind, and biomass
  • Anthropology Ph.D. student Shannon May’s work on the post occupancy evaluation of China’s fact eco-village

The greatest challenge is developing the institutional structure and pedagogy to create an effective framework for this interdisciplinary collaboration to flourish. The impact that the built environment has on our planet’s future has never been more critical to our survival and presents us with our greatest opportunity for change.

Climate for Change

The potential of landscape design to transform the built environment from its current energy-intensive state has largely been overlooked.

Contemporary energy conservation efforts emphasize architectural and engineering solutions. Green building is a trend, still divorced from the landscape and the garden, both which are green to begin with. Integral to any discussion of sustainability or green building should be a consideration of the capacity of the designed landscape to create and modify microclimates and thus conserve energy.

Prior to the oil embargo of 1973 which alerted the world to its overdependence on diminishing fossil fuel reserves, building and growth patterns had become extremely wasteful. In reaction to the prevailing attitudes that our energy supplies were inexhaustible, many architects and landscape architects began to investigate passive design techniques. Unfortunately, our fascination with later Information Age technologies diverted our attention away from these early advances and investigations.

Many of the principles of passive design explored in the 1970s had their origins in the distant past. Throughout landscape history, the harsher the climate, the more ingenious the devices and methods became for creating physically comfortable spaces. A review of historical gardens would reveal many precedents for energy efficient design. In fact, the principles of climatic site planning reach back thousands of years. In Mediterranean climates, such as ours, people lived in close connection with the landscape, adapting their environments to create comfortable living spaces by observing natural patterns and systems. One doesn’t need a complex computer model to understand how the sun moves across the sky.

The move towards an energy responsive ethic provides us with a second chance to incorporate the knowledge and methodologies from our ancient and recent pasts and implement these ideas on a large scale.

Earth

lemonaia
A solar-powered limonaia defines the edge of a south-facing terrace at Vicobello, near Siena, Italy. The adjacent formal garden is essentially an orange grove.
As early 36 BC, Varro identified the southeast-facing hillside as the ideal location for a villa. (The form of the typical “suburban” villa included house and grounds together with the total complex understood as a unit.) The southeast orientation allowed the dwelling and the garden to catch the prevailing summer breezes and block the cold northern winds in winter.

During the Renaissance there existed a “Canon of Horticultural Rule” which presented a format for placing elements in the landscape. According to the canon, the bosco or planted woodland was an integral element of the site plan. A dense plantation of evergreen trees placed on the northern side of a structure not only blocked the winter winds, but also played an important ecological role, providing abundant vegetative mass for photosynthesis and wildlife habitat. This is an extremely important lesson for contemporary design: establishing a ratio of vegetative mass to built form and maximizing tree canopy can provide great climatic benefit. A plantation mass can effectively block the sun, and thus reduce ground level temperatures and insulate buildings. Planting large areas of deciduous trees with broad canopies will produce significant quantities of oxygen, while reducing ambient temperatures in the summer.

Fire

Contemporary ideas of passive solar design are also rooted in history. All living material can trace its origins to the heavenly fire. Without the sun we cannot thrive. In the past, solar orientation was a guiding principle in laying out garden and dwelling. Leon Battista Alberti promoted the common-sense use of passive solar design as long ago as 1482. He believed that loggias should be designed not only to capture beautiful views, but also to provide year round comfort by admitting sun or breezes, depending on the season. Alberti even proposed the use of glass to keep out the winter wind and let in the undefiled daylight.

Pliny the Younger’s Laurentine villa near Rome contained a unique solar device called the heliocaminus, or heated sunbath, which was a garden room enclosed on four sides and open to the sky to capture the sun’s rays. The solar-heated heliocaminus of the Romans evolved into the giardino segreto or secret garden, ever popular in Italian Renaissance gardens. Usually a sunken space with decorative stone or stucco walls, the enclosed room deflected cold winds and collected heat from the sun. One of the finest examples of the giardino segreto can be found just outside of Florence on the grounds of the Villa Gamberaia. Located directly across from the central entrance to the villa is a narrow secret garden, hardly more than 20 feet across and 100 feet long. This diminutive garden runs east to west to ensuring exposure to the morning and afternoon sun.

Being aware of the movement of the sun also allowed Renaissance designers to develop garden elements for the year-round growth of crops. The limonaia was one of the first solar-powered spaces in temperate climates that harnessed and stored solar energy for the winter storage of citrus plants. Similar in form to the loggia, the limonaia faced south and was enclosed with large plates of glass, like a greenhouse. Operable windows regulated interior heat. Plants were placed on tiered platforms at the base of the solid north wall to receive plenty of sunlight.

The Villa Medici at Castello, a few miles from Florence, had over 300 varieties of fruit trees in cultivation, essentially making this villa a functioning agricultural landscape set within a beautiful formal garden. The ornate formal gardens of the Italian Renaissance, so often criticized as exercises in geometry imposed on nature, continue to have relevance for designers and planners today. As agricultural centers they provided sustenance for not only their owners, but the families that cultivated and maintained them. Most of the farming villas produced cash crops and could be considered self-sustaining in many respects.

The limonaia, integral to the Italian garden, can be retrofitted into contemporary gardens to serve as the foundation for sustainable communities. Relevant today for its ability to capture and store the sun’s heat, a limonaia can be an instrumental device for growing food as we move towards a more sustainable future where gardens provide not only beauty, but sustenance.

Air

nishat (3)
A shady pavilion built directly over a canal and filled with jets of aerated water at the Nishat Bagh, in Kashmir, produces a form of natural air conditioning.
Garden designers have sculpted the movement of air and designed air-cooled spaces throughout history, particularly in Mediterranean climates. Today’s designers can exploit the cooling effects of moving air to reduce the energy and environmental costs of using mechanically-cooled air-conditioning systems. Microclimates can be designed to take advantage of the cooling properties of air flow. Air can be directed, funneled, and accelerated with simple landscape and architectural forms such as seats, arbors, pergolas, garden pavilions and porches.

The Alcazar Gardens of Seville contain one of the cleverest air-cooled seats in garden history. This extraordinary bench is situated in the Jardin de la Danza, a small garden room within a series of enclosed patios. Extremely thick walls enclose the garden on the east and west, while the southern wall addresses the prevailing summer breezes with an intimate niche. Between two built-in benches, a small arched window with a decorative metal grill frames a picturesque view of the adjacent lower garden. As the breeze flows, it is forced through the small window, thus increasing its velocity at its point of exit on the opposite side of the opening. (We now understand this phenomenon as the Venturi Effect.) In addition to being naturally air-conditioned, the enclave remains cool in the summer because the thick walls that enclose it act as an insulator, while the white walls reflect the heat produced from the intense rays of the sun. This ingenious form of air conditioning remains effective to this day.

Alleés are parallel rows of evenly planted trees placed on either side of a path, avenue, or roadway, and are usually long enough to create a walk or promenade of some distance. They are commonly used to direct views, organize spaces, create vistas, and unite various parts of a garden. An alleé can also stimulate the movement of air and be used to direct air currents into specific areas of the garden, garden structures and dwellings. When planted along south-facing slopes, alleés benefit from naturally rising air currents that push air from the shaded space into building interiors.

In desert climates garden pavilions were commonly built with a south-facing porch balanced over a large pool. The shaded interior porch with its high ceiling would catch the cooled air that passed over the pool. Many variations were possible, but a connection to the garden was essential. To augment the cooling effect of the porch, the Persians suspended a curtain from the façade of the pavilion to block the hottest rays of the summer sun. The curtain was pulled back in the winter to allow the sun to enter and warm the space. A soft and luminous quality of light filtered through the fabric. When the curtain was fully extended over the pool, it acted as a large air scoop, concentrating the ephemeral breeze, and capturing water evaporating from the pool. In addition, the cloth could be moistened with rose water, cooling and scenting the interior as the moisture evaporated. The Persian garden pavilion and the Italian summer house are both designed for natural coolness. As intelligent passive design devices they represent relevant footprints for reducing energy consumption in the contemporary built environment.

Water

gamberaia
The sunken room at Villa Gamberaia in Settignano, Italy, functions as an effective solar collector for winter comfort.
The importance of water as a commodity cannot be underestimated, especially in California. Without water there can be no life. And in past cultures, the collection, storage, and movement of water was a priority in order to maintain a predictable supply throughout the year. Only then could passive microclimates be enjoyed and the art of the garden flourish.

In California, every drop of water that falls on a site should be captured and stored. Extremely high temperatures combined with lengthy droughts have turned the American west into a tinderbox. In many regions of the world water is being used more quickly than aquifers can be replenished. Water tables are falling. If this trend continues it will have a profound impact on food production and living standards.

The control and disbursement of water in California has become a politically explosive issue. Perhaps only through enlightened watershed management and a change in public attitudes toward consumption can a dependable supply of clean water be preserved. Continued research of both historical precedents and current technologies, combined with the promotion of sustainable agricultural practices, are the first steps towards redefining our relationship with water. Water is not merely a resource to be exploited for human convenience, but rather a nurturing force that links and sustains all life on earth.

In many arid climates cisterns were used as a fundamental method of storing as much rain water and runoff as possible for use during the dry season. In Los Angeles, before aqueducts brought water from the north, residential cisterns were critical elements in a system that had to balance the effects of both droughts and floods. This tradition can be resurrected in the contemporary landscape. Runoff can be directed into insulated closed cisterns built into new structures or retrofitted into existing structures.

Long before modern drip irrigation, the Persian gardener developed a simple yet efficient method for subsurface irrigation. In Yazd, one of the hottest spots on the Iranian plateau, “condensing jars” significantly reduced the amount of water lost to evaporation. Earthenware containers were placed in the soil between rows of plants, set with their narrow necks protruding just above the surface. When filled with water these containers “sweated” moisture through their porous earthen sides, directly irrigating the roots of the vegetation. Condensing jars, removed from exposure to sun and air, effectively conserved water by protecting it from evaporation.

Aerated water was often employed to cool garden structures. Forcing water under high pressure through miniature openings or thin slots would suspend fine drops of water in the surrounding air, humidifying it and lowering the temperature. To produce this effect, water would first be pumped into reservoirs on the roof. With gravity pressure, the water would descend through columns pierced with thousands of tiny holes, creating an almost invisible mist that gently cooled the room. Aerated by thousands of tiny misting jets, these garden rooms were a tranquil oasis for the body and mind.

Conclusion

Many advances have been made in green architecture and alternative building. The US Green Building Council has established standards for sustainable buildings. However, these achievements need to be integrated with energy-conserving, sustainable landscapes that create new gardens on a regional scale. New and exciting opportunities lie ahead for the creation of unified garden and architectural forms that not only conserve energy, water, and agricultural lands, but are also works of art and places for spiritual renewal.