When installing underground storage tanks you must always consider the level of the water table, surface pressure and an anchoring system. A great solution, if feasible, is to install tanks under a driveway, building or patio with access through a fitted manhole.
We have been designing large-scale residential and commercial rainwater harvesting systems in California since 1997, primarily for irrigation use in the landscape. We like to consider our landscapes that incorporate rainwater harvesting as “closed loop systems,” as we begin the design by determining our end-water usage.
It Starts with Plant Selection
It starts with the type of plants we choose. We look at the irrigation requirements for the proposed planting areas. In our design we hydrozone, i.e., put plants together with similar water needs and choose a high percentage (75–90 percent) of our plants from a rich, diverse native and drought-tolerant plant palette. This way we get the most aesthetics and the most efficient water usage out of our site. Many of these plants add more water-saving benefits to the site, in that they help bind the soil and prevent erosion and excess runoff.
Lawns, of course, are the biggest water users, so reducing lawn areas reduces water needs, which in turn requires a smaller rain harvesting system. Our goal is to supply most (or all) of our plant irrigation needs with harvested rainwater.
Three 7,500-gallon “Short Boy” water catchment tanks are placed beneath a patio.
Other site-specific factors we consider in determining our end-use needs for irrigation water include water percolation rates (dependent on soil type), and evapotranspiration (ET) rates—how fast the water evaporates from or absorbs into the soil. These rates determine how often and how much we need to apply water to the plants. My experience is that most homeowners over water their plants by a factor of two to three times. With the use of “Smart” ET- based automatic irrigation controllers we can now plug in the data for each zone, including the types of plants, soil type and topography. The controller sends this data to a local satellite station to determine the ET rate for the day. Only the amount of water needed on any given day is then administered to the plants. Usually included is a rain sensor that automatically turns the irrigation off if there is any precipitation. When operating on a rainwater system, the irrigation water supply is limited for the year, so we also recommend the irrigation system includes a flow sensor, which when a leak is detected informs the owner or landscape management team of the problem via email or cell phone.
We use drip irrigation as our preferred method of irrigation. Subsurface drip is becoming more popular in the U.S. Subsurface drip is said to deliver 90 percent of the water directly to the roots of the grasses and plants, compared to 60 percent when using a spray system. It is also estimated that subsurface drip irrigation can save up to 70 percent more than spray heads, and up to 25 percent more than regular drip systems. We then add a two to three inch thick top layer of woodchip mulch to the planting areas to add to the efficiency of the system.
This component system of pumps and pipes source the water stored in above ground tanks and is connected to a “Smart” ET- based automatic irrigation controller. The controller sends this data to a local satellite station to determine the ET rate for the day, ensuring only the amount of water needed on any given day flows to the plants. The irrigation system should include a flow sensor to detect leaks.
Filtered Roof Water
In most cases, the roof surfaces of the home (or other buildings on the lot) can provide the quantity of water needed for a full planting design, so importantly, we determine in advance our irrigation needs and design for the greatest efficiency. Roofs are the cleanest rainwater source, as opposed to surface drained storm water. Because of the particulates that storm water picks up on landscape surfaces, such as asphalt and concrete, it is typically of a lower quality. From the roof downspouts the rainwater may be directed through filters, which are usually quite simple, to appropriately sized storage tanks and then pumped and filtered again before entering directly into the efficiently designed irrigation system. It is important to size the pipes, filters, and storage system appropriately, based on the runoff rates of a heavy storm in a particular area. There also must be a well-planned solution to accommodate overflow during a particularly heavy storm.
Above or Below Ground Tanks
There have been many successful rain-harvesting systems installed in California. An above ground rainwater storage solution is the least expensive, but most space-consuming alternative. We typically install above ground tanks when there is enough room to screen them from view, although some landscape architects are now specifying attractive rainwater tanks as site features if the planting area is small and does not require much water storage, such as a small inner-urban back yard.
Underground tank systems usually cost twice as much to install because of the excavation, but of course have far less visual and spatial impact. One must always consider the level of the water table, surface pressure and an anchoring system when installing underground storage tanks. A great solution, if feasible, is to install underground tanks under a driveway, building or patio with access through a fitted manhole, such as is typical on a city street. Either way, the overall water savings is well worth the investment, if the system is well designed, and there is enough water captured to handle most of the irrigation needs of the site.
Ready for tank delivery! The water gets to the underground tanks from roof downspouts, then is directed through filters, which are usually quite simple, to appropriately sized storage tanks and then pumped and filtered again before entering directly into the efficiently designed irrigation system. It is important to size the pipes, filters, and storage system appropriately, based on the runoff rates of a heavy storm in a particular area.
Bobby Markowitz is Principal of Earthcraft Landscape Design and a frequent contributor to Green Architecture Notes.
You’ve probably heard of LEED, (Leadership in Energy and Environmental Design), and maybe if you’re in California you have heard of GreenPoint Rated or the eminent CALGreen Code, but wrapping your head around how these standards compare and what they mean to your building project can be a big task. In this article, I’ll try to break it down a bit. For more detailed information, please visit the web sites of each compliance organization: LEED, GreenPoint or CALGreen
LEED, developed by a non-profit organization called the U.S. Green Building Council, was really the forerunner in developing an industry standard for sustainable building practices in the United States. GreenPoint Rated (GPR) is a system used for houses and developed by Build It Green, another non-profit based in California, with the goal of creating a standard that would be less expensive and therefore more accessible to homeowners. CALGreen is a building code that will become effective in California for both residential and commercial buildings on January 1st, 2011. Some municipalities in the Bay Area are even requiring permit applicants to get certification from GPR and/or LEED as a way of ensuring that CALGreen standards have been met.
Both GPR and CALGreen systems of measurement are based loosely on the LEED standards, but there are some differences and modifications made to clarify or make easier the systems of measurement that are in place. For simplicity, I’ll compare the residential measures as a common base for all three systems. All systems break green building components down into areas of sustainability that they are addressing with varying names and sub- categories. However, the general concept is shared: sustainable building practices fall into these categories:
- Water Efficiency
- Energy Efficiency
- Material Resources
- Environmental /Air Quality
GPR arranges their checklist in a way that relates more closely with building systems themselves such as structural frame and finishes, but are then cross-referenced with one of the above categories. All of the systems have mandatory or prerequisite measures that must be met, and the two voluntary systems (LEED and GPR) have additional strategies that go above and beyond to earn points. A minimum number of points is required for certification, and the more points earned the higher the level of certification.
Since LEED and other green building certification systems have begun gaining popularity, there have been a number of articles and independent studies published on the value added by achieving certification, such as “An Inconvenient Value” by www.AwarenessIntoAction.com and “The cost & benefit of achieving Green buildings” by Davis Langdon. We hope the trend continues to catch on and the up-front cost continues to come down as demand for sustainable building materials and methods continue to rise.
Now let’s dig a little deeper into the subcategories and the particular goals of each. The charts below are not meant to be comprehensive, but instead give an overview, hitting the highlights of each system. Note that The CALGreen system has two “Tiers” that can be sought, which require additional prerequisites. I’ve included these prerequisites under ‘additional points/measures’ in order to maintain clarity of the basic requirements in the charts below.
Bridgett Shank works at Feldman Architecture and is a frequent contributor to Green Architecture Notes.
Advances in green technology and a fondness for reused or reclaimed materials have led to more innovative and creative sustainable products for the home. As a new addition to Green Architecture Notes, we will be posting a new section on products that we find to be perfect examples of how green IS beautiful, practical, and inspiring. In this post, the adaptive reuse of reclaimed materials yield stunning furnishings and fixtures which divert materials from landfill and reduce energy used in the production of new materials.
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Products in Top Row:
left – The Scrap Light collection from Graypants demonstrates how simple pieces of salvaged corrugated cardboard become mesmerizing. These lanterns create stunning patterns with light and shadow in any space.
center – The Studio Sectional from Environment Furniture has a relaxed, informal quality. Upholstered with recycled army tent canvas fabric, the distressed and weathered characteristics will continue to develop and patina over time.
right – Urban Hardwood is best known for breathing new life back into trees that would typically be heading straight to the landfill. The Sycamore Slab coffee table positions a pair of slabs side-by-side and fastens them together with steel infill. This simple design lets the wood’s beauty speak for itself.
Products in Bottom Row:
left -The Asturia Armchair from Espasso, designed by Carlos Motta, is strong, durable, and elegant. Built from reclaimed and demolition woods collected in urban centers like Sao Paulo, this chair is suitable for both indoor and outdoor use.
center – Graypants is redefining the “recliner” with their latest design, the slice chair. Constructed from scraps of flat sheets of plywood, the slices allow the ottoman to slide out, creating a lounge chair.
right – Ending with a PUNCH! of color.… We introduce an area rug from the Color Reform Collection by ABC Carpet. This rug is hand-woven from recycled Indian Sari silk, then over-dyed to create a powerful statement packed with mono-chromatic vibrancy.
Cork is a fantastic, 100% natural, material that has been used as an insulting material for years, although is not well known by most of the people working on sustainable and zero carbon projects.
So what makes this material special?
Cork is the bark of Cork Oak (Quercus Suber), collected every 9 years and later transformed and adapted to different uses. During its life, cork retains an elevated portion of CO2 and requires very low energy to be transformed.
The most common use in construction – as a thermal insulation material – is Insulation Cork Board (ICB). This material is produced using raw cork (which can be a sub product of the cork stopper industry) in granulated form that is placed in autoclave where it stays for 20 minutes under vapor at 360º C (680º F). As the cork starts to expand and forms into blocks, it starts to agglutinate by means of its natural resin and also gains its characteristic brown color. The process is free of any artificial chemicals keeping the material 100% natural.
Cork is particularly resistant to insects and maintains its characteristics over time. In 2000, in the north of Portugal, a very large cold store built in 1969 was dismantled. Cork was used as thermal insulation and it was fully recovered to produce new cork based materials. What is remarkable is that the cork was analyzed in laboratory and had exactly the same characteristics as new cork meaning that its use hasn’t diminished any of its qualities.
In a recently completed K-12 school renovation project where we used cork extensively as a thermal insulation material on roofs (metal and concrete slab), we came to the following conclusions:
• The material behaves very well during construction, in good or bad weather;
• No special skill is necessary to apply this material;
• Any cuts or changes needed during work are easily achieved on site.
In an ongoing project we’re using the same material as a roof and facade insulation as part of a render system and expect to achieve a very high performance for the building.
In recent years, Portuguese architects have been exploring this material as a cladding. The Portuguese pavilion in the Hanover Expo 2000 used cork blocks as a facade. Recently, the Portuguese Pavilion in the Expo Shanghai which was entirely covered in cork panels won a design award and also in Architectos Anonimos ‘s Cork House which is shown below.
Coimbra, Portugal - Pavilhão de Portugal Expo 2000, Álvaro Siza & Eduardo Souto de Moura.
As a conclusion, we can say that cork is a natural, recyclable and environmental friendly product, highly adequate for green or zero carbon projects, as insulation and cladding material, with a guaranty of total reuse in the end of the building life-cycle making it a very good cradle-to-cradle material.
Cork House by Arquitectos Anonimos, Portugal.
For more information from a cork supplier, see Amorim Cork Composites.
Fernando Ribeiro studied in Portugal and England where he obtained a Master Degree in Architectural Design after which he worked in Macau on several high profile projects. He is the co-founder of Arqwork Arquitectura, a practice engaged in a broad range of projects from K-12 schools to retail spaces. His practice is driven by passion in designing buildings and enhancing people’s lives. Fernando’s interest in sustainable design led him to engage in developing a more practical approach to architecture through the use of simple technical solutions and natural materials.
As a new segment of Green Architecture Notes, we plan to periodically share images from talented photographers and authors who are focusing on Sustainability and Design. Our inaugural post is drawn from the aptly named Green is Beautiful book by photographer Claudio Santini and Dafna Zilafro. Green is Beautiful offers 30 stunning residences each exemplifying sustainable design. Below we offer images from a few favorites. For more information, see Claudio Santini’s website, www.claudiosantini.com, or Amazon.com.
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Description of Images Top Row
left – Carver + Schicketanz Architects creates a warm modern space that ties expansive views in with tactile, rustic salvaged materials in the Treadwell Residence.
center left – At Sintesi Design’s Kuperberg Residence, large pivot doors and a shade trellis blur the boundaries of indoor-outdoor living.
center right – Working within a tight urban lot, Zack DeVito Architects masterfully directs daylight from overhead to bring natural light deep into the Chattanooga Townhouses in San Francisco.
right – Pugh+Scarpa incorporates clean energy generation into the Scarpa Residence by wrapping a photovoltaic array across the roof and down one façade of the building.
Description of Images Bottom Row
left – O plus L’s Nordine Residence features clean lines and celebrates the use of thermal mass in a board-formed concrete fireplace and concrete floors.
center left – Stone walls and concrete floors make up a simple and elegant material palette for the Piperno Residence by Luigi Villano.
center right – Through careful siting and the use of a green roof, Feldman Architecture allows House Ocho to sit quietly in the landscape, while views of the lush terrain dominate the visitor’s experience.
left – Recycled timbers from an old barn span the dining room and frame the sweeping view of the Petaluma River at the Sutton Residence by Sutton Suzuki Architects.
Hannah Brown is a current contributor to Green Architecture Notes, works with Feldman Architecture and teaches at California College of the Arts in the Architecture Department.
From time to time, the Editors of Green Architecture Notes turn the spotlight on businesses where sustainable products or technologies have been implemented in a move toward a more environmentally-conscious practice. Mueller Nicholls, a General Contractor and Cabinet Shop in Oakland, California, is one such business which is leading by example through a pioneering effort to reduce their reliance on fossil fuels.
Solar panels atop the Mueller Nicholls Builders' cabinet shop
A general contractor and cabinet shop will typically use a significant amount of energy for several functions, most notably for running portable and stationary tools, powering computers, illuminating facilities, and shuttling workers and materials to and from jobsites. At Mueller Nicholls, we’ve long focused on making our operations more sustainable, and recently, we’ve concentrated on greening up two conspicuous sources of energy demands in our business. In the spirit of inspiring other companies to do the same, we wish to share some key points from our experiences investing in alternate and green sources of energy to run the shop and office as well as some of our company vehicles.
The cabinet side of the Mueller Nicholls’ business uses roughly 10,000 KW of electricity every month. We’ve been eying the sun for quite some time as a potential power source, and in the summer of 2008, we took the plunge and installed a complete photovoltaic solar system. The system generates 90% of yearly energy needs; we’re thrilled to have cut our dependency on less renewable sources of energy by such a large margin.
Although we focused on the sustainable concerns when installing the systems, financial considerations also came into play. At that time, the federal tax credits were substantial and just about to expire. We determined that the payback period would be a brief eight years (we’re 25% there!), and the idea of the monthly payments going to a local bank as opposed to a large utility was attractive. For the PV system, the monthly cost of financing roughly equals the monthly power bill prior to installation of the system. Mueller Nicholls’ location in West Oakland made the logistical considerations very easy. We have 250 panels that fit easily on the 16,000 square foot flat roof of the cabinet shop and also plenty of space for the inverters at the electrical panels. The entire crew is aware that we’re getting our energy from the sun, which is a source of pride for green-minded employees.
With regards to our transportation, in 2006 we began replacing our standard SUVs and sedans in order to upgrade to hybrid vehicles. Having company cars at the office allows a large number of employees to bike to work – sometimes up to seven employees out of twenty-two – and then to share the cars as necessary. At this point in time, there are four hybrid company vehicles and our fleet gas consumption has decreased by roughly 1,300 gallons per year. At $3.00/gallon, this saves $3,900 per year in fuel costs.
One of the four hybrid vehicles in the Mueller Nicholls fleet
When we purchased these cars, electric cars were less than practical from many standpoints. Hopefully by the time we need to retire this fleet, we’ll be able to switch to electric cars. We also have two diesel delivery trucks, which we plan to convert to bio-diesel as this option becomes financially feasible. We look forward to the day when we can expand our PV system in order to charge electric vehicles and have portable PV solar panels as a way to provide power to a job site.
While our journey towards using more renewable energy sources for our power consumption is far from over, we’re pleased to have taken these first steps. In a marketplace flooded with companies that tout their sustainable practices, we believe it’s crucial to put our money where our mouth is and to reduce the impact that our cabinet and construction practices have on the planet.
Jill Moran is a construction professional with 20 years of varied experience in high-end residential remodeling. Her recent entry into motherhood, timed precisely with the downturn in the local construction industry, has resulted in a slight re-engineering of her career. She currently works closely with the management team at Mueller Nicholls, with an emphasis on communicating to the world at large about residential remodeling.