by Michael Igo, Affil. ASLA, PE, D.WRE, LEED AP, CID
In the age of awareness of climate change, we often hear the terms “100-year storm,” “500-year tides,” or “25-year drought” thrown around. Intuitively, we tend to think that a 100-year storm occurs once every 100 years. However, this is only partly true, as there are key phrases missing from this notion: a 100-year storm will occur once every 100 years on average and based on past data.
The use of an X-Year event derives from what is known in mathematics as the exceedance probability, or the likelihood of an event being greater than a predefined parameter in a given timeframe. Statistics of past data (storms, tides, earthquakes, etc.) are used to create charts based on size and the probability of occurring.
Western states face new struggles to match water use with water supply. Landscape architects are finding a wide range of regulations and incentives to drive landscape water use down and support a growing population.
The 2019 Colorado River Drought Contingency Plan committed each of the Colorado Basin states to reduce the amount of water they take from the Colorado River during drought conditions. The junior water rights holder, Arizona, committed to a 7% reduction in annual water use starting in 2020. That state is home to the second-fastest growing city in the U.S., with a 56.6% increase in population since the last census: Buckeye, AZ. This is one of several dynamics that are impacting water policies in the Colorado Basin states: Arizona, California, Colorado, Nevada, New Mexico, Wyoming, and Utah.
To reduce water use states are turning to the remaining area of conservation potential: water that is consumed in urban landscapes. In past years, urban water use per capita was reduced through promotion of low-flow bathroom fixtures and water-wise clothes washers that have been replacing old models. A sampling of many approaches that Western cities and counties are applying to meet their water conservation goals follows.
The 900-acre Pontilly area of New Orleans is composed of two moderate-income, minority-majority neighborhoods—Pontchartrain Park and Gentilly Woods. For decades, these neighborhoods have repeatedly experienced losses due to flooding and both were severely damaged by Hurricane Katrina with hundreds of homes destroyed.
In response, the neighborhoods collaborated to form the Pontilly Disaster Collaborative (PDC) that seeks solutions to localized flooding issues caused by rainfall events. PDC approached the New Orleans Redevelopment Authority (NORA), who had received ownership of many residential properties in Pontilly following Katrina, to utilize vacant lots for managing stormwater. A landscape architect at NORA recognized the value of the community organization’s idea and began seeking funding through the FEMA Hazard Mitigation Grant Program (HMGP). Continue reading →
Water conservation is an important topic in landscape architecture, as its professionals are stewards of the built and natural environment for society. Without a balanced water supply, drinking water, sanitation, ecological balance, and safety cannot be secured for our existence. Thus, when we speak of water conservation, what we really mean is freshwater or domestic water conservation.
Furthermore, some of the areas of water conservation discussed below are not only about water quantity conservation, but also water quality conservation in our natural surroundings. The adage “an ounce of prevention is worth a pound of cure” is true in water conservation in the sense that not only does saving and using less water in landscapes reduce the quantity of water consumed, but it also prevents poor quality water for reuse or filtering site water from being reintroduced into the environment and conserves existing precious clean freshwater for domestic uses and for habitats.
When a site is altered from its natural or previously disturbed state, the patterns of rainfall runoff and infiltration are also altered. Natural areas that were once reliant on ample infiltration can be deprived of recharge from paved and developed sites by sealing off underground soils from the atmosphere or just by increasing the velocity of water movement across a site such that runoff does not have time to infiltrate. High velocity, unmitigated stormwater flow can cause erosion of valuable land areas, transport sediment that could fill in and cause eutrophication of natural water bodies, cause damage to sites and structures downstream, and serve as a massive heat exchanging liquid as rain falls on, passes across, and carries away the latent heat trapped in urban pavement—polluting otherwise ecologically-balanced freshwater supplies and habitats.
Modifications to the American Society of Landscape Architects (ASLA) Headquarters building, now known as the Center for Landscape Architecture (CLA), are nearing completion for higher performance in water conservation. The exterior improvements are of particular interest to landscape architects and others who are sustainably-minded, as part of their ongoing Energy-Starinitiatives. In addition to interior upgrades and hardscape improvements outside, the primary improvements of high interest to ASLA’s Water Conservation PPN include the water-harvesting system and the WaterSmart approach to irrigation for the greenroof, the new courtyard (east of the building) and the planted canopy overhanging the front windows and entry on the north side.
Familiarity with a whole host of water resource professionals, environmental activists, and scientists who play an active role in helping to shape the federal government’s role in water resources management enables me to share details about the controversial New Madrid Levee Project.
A resolution from the White House Council of Environmental Quality (CEQ) provides an overview of the St. John’s Bayou and New Madrid Floodway Project (New Madrid Levee project for short), a proposed quarter-mile levee in southeast Missouri. This resolution was the result of a deal CEQ brokered between the United States Fish and Wildlife Service (USFWS) and USACE, who disagreed on whether mitigation the USACE proposed was adequate to replace the wetland and floodplain functions the New Madrid Levee would eliminate.
One might conclude that this case study is a poster child for how to (or how not to) manage our big river systems in the US. With the resolution, CEQ stopped the pending USACE project in its tracks while it was under final stage review to construct the New Madrid Levee. The New Madrid Levee would have severed the Mississippi River from the last place in all of Missouri where the river can flow into the floodplain to create backwater habitat that is vital for flood attenuation and fish and wildlife habitat. Approximately 50,000 acres of wetlands (comparable in size to Washington, DC) with valuable water conservation and critical fish and wildlife functions would be eliminated should the proposed levee ever be built.
For those of you interested in water conservation planning and design, the 2015 Annual Meeting & EXPO in Chicago offers a diverse array of learning opportunities in both traditional areas, including storm-water management, riparian and wetland restoration, green infrastructure, as well as in emerging topics, such as natural water features and water reuse. Please find the following list of sessions that may appeal to Water Conservation PPN members and enthusiasts:
As the notion of “sustainable sites” becomes increasingly important, the Natural Water Feature can provide the rejuvenating and life-affirming elements of water, while maximizing a site’s sustainability factor. Borrowing design techniques from natural and constructed wetlands and the increasingly popular “natural swimming pool,” the Natural Water Feature offers a green alternative to the traditional, chlorinated, and resource consuming display.
So what exactly is a Natural Water Feature? While the definition is still being debated, there are three main aspects upon which everyone agrees:
First, the display will use a non-chemical water treatment system. The Natural Water Feature relies on a living ecosystem in lieu of adding chlorine and acid. Chemical pollution becomes a non-issue—nature does the work.
Second, the Natural Water Feature should use minimal mechanical gear and electricity. This means eliminating or downsizing the mechanical filter and its pump, the effect pump, and other equipment—which translates into using less energy.
Third, the display should use recaptured water where possible, and in general, minimize the use of potable water. Some localities demand this for any water feature.
I just hosted an event where twenty-five people watched a video of a flushing toilet and gave it a standing ovation. Granted, I live near Hollywood in Los Angeles, but this was not a showing of some avant-garde cinema (today’s Hollywood cinema could never be confused with avant-garde; perhaps, if Captain America were flushing the toilet). This was a combined USGBC and Living Building Challenge meeting to figure out how to get to Net Zero Water in LA.
The toilet in question was a composting toilet that uses no water, but a highly evaporative alcohol lubricant to flush the waste into a digester unit in the basement. Gross? Maybe, but we Californians have to come to terms with the inevitable conclusion that our state’s multi-trillion dollar, 100 year-old water infrastructure system transporting Northern California snowpack to Southern California bathrooms will not be enough. California holds 10% of the country’s population, provides 40-60% of the nation’s fresh fruits and vegetables, and has a big enough industry and economy to be rated 8th in the world. California will only continue to get more populous, hungrier, and thirstier over time; the flushing composting toilet was not only grand entertainment for us but a hopeful sign that we will be able to solve our water resource problems by being smarter designers.
What does this have to do with landscape architecture, you may ask? Well, we landscape architects and related industries need to be smarter and more careful in the conservation of our water resources.
Given the urgent need to address aging water infrastructure across the United States, public-private partnerships, or PPPs, offer a possible solution. The ongoing discussion of PPPs’ potential includes an overview of 2013’s PPP-related developments by Michael Deane, Executive Director of the National Association of Water Companies, for The Huffington Post and an article by Giulio Boccaletti, Managing Director of Global Water for The Nature Conservancy, in The Guardian that takes a look at financing solutions for natural infrastructure.
Earlier this year, ASLA’s Government Affairs Manager, Mark Cason, observed a roundtable discussion of PPPs focused on water supply and treatments. The roundtable, hosted by the House Transportation and Infrastructure Committee, addressed the challenges municipalities face in operating, maintaining, and financing their water and waste water systems. Panelists also outlined the substantial federal and state investments needed to address all of the demands, especially as the original infrastructure reaches the end of its life cycle.
Synthetic Surface Sport Fields for Water Conservation & Long-Term Carbon Footprint Reduction
Sustainability experts typically agree on two measures for high performance sport fields: total fresh water saved, and net reduction in carbon footprint with all factors considered over the life cycle of the sports field.
So, what are the water conservation features for synthetic surface sport fields, and what other factors determine how green your sport field grass is? Before outlining features and factors to consider, we’ll take a look at a project at Western Washington University that is an example of a high performance sports field design with synthetic surface fields that are truly greener, including high performance for water conservation.
“If the design and specification is done right, all-weather synthetic surface fields including adequate subsurface drainage will minimize runoff. This is especially important at our Western Washington University (WWU) campus in Bellingham, Washington in the Pacific Northwest,” says Linda Beckman, Vice President for Student Affairs at WWU. “Ideally, synthetic surface will be selected for high recycled content, as a low-VOC product for air quality concerns, and will be maintained properly. Upfront, we decided to fund proper maintenance and also decided it will be recycled when it nears the end of its life, and to select a consultant who understands the full picture of environmental performance from products and systems. Our Pacific Northwest strong environmental commitment is met by using the sport field surface system we approved—we did it right and we did it green.”
Flying home from 2013 ASLA Annual Meeting in Boston, my flight back to Seattle encountered typical Midwest winter weather in the Great Lakes area, perhaps the only large region in the US without an existential threat to their fresh water supply. My hours traveling gave me time to reflect on the Annual Meeting’s over a dozen sessions related to water conservation. Three education sessions plus our Water Conservation PPN Meeting are featured below, all of which reflect how the water conservation focus at the 2012 Phoenix conference remained high on the national agenda at the Boston 2013 conference. Below, you’ll find my thoughts on a project in San Diego, biophilic design, plus discussion among a dozen leading water conservation professionals.
Whether you attended the Annual Meeting or could not make the trip to Boston this year, I’m happy to share a few highlights. Each session title is a link, providing more information about the presenters or subject of that session, so please take a look!
From meeting increasing demand with aging water infrastructure to planning for extreme weather events, the challenges of managing water wisely are growing ever more numerous and complex.
The World Resources Institute recently released a report, Natural Infrastructure: Investing in Forested Landscapes for Source Water Protection in the United States, on how forests, wetlands, and floodplains can play a central role in avoiding and alleviating water-related crises. Drawing on the expertise of more than 50 authors, the report describes in detail how currently underutilized natural infrastructure might be harnessed to improve water management practices, and the many opportunities there are for doing so. The case studies included range from forest-based efforts in Maine, Oregon, North Carolina, Colorado, and Washington to a stormwater control program on Staten Island, New York.
The report is intended to be “a call to action for water utility staff and land managers alike to bring natural infrastructure into focus in their institutions, with this guide as a foundation from which businesses and municipalities can innovate in the face of a growing water crisis.” By investing in natural infrastructure now, water managers can both reduce the costs of water management and help to ensure access to clean water for generations to come.
A recent interdisciplinary design competition, Infill Philadelphia: Soak it Up!, encouraged a wide array of professionals to propose innovative solutions addressing Philadelphia’s aging combined sewer system. According to the Philadelphia Water Department (PWD), about 60% of the city still operates on combined sewer. Through the city’s efforts to become the greenest city in America by 2015, Philadelphia has become a national leader in stormwater management planning and policy by creating Green City, Clean Waters, a progressive 25-year stormwater management plan focusing on using green stormwater infrastructure to reduce pollutants in local waterways.
Nevada DOT responds to water and budget limitations for landscapes.
Embracing soil as an important player in water conservation, the ASLA Water Conservation Professional Practice Network spotlights the Nevada Department of Transportation (NDOT) Landscape Architecture, where they have adopted a standard policy of “no irrigation” for southern Nevada freeway landscape enhancements. To respond to that challenge, designers are utilizing porous inorganic amendments as an aid to increase plant-available water in the soil in a region where rainwater harvesting challenges are unique.
Cool pavement systems as a hot mix asphalt alternative is encouraged by state legislation in California.
The Water Conservation PPN is highlighting two ways cool pavement technology save water. First, reducing paving temperature reduces water evaporation from soil adjacent to paving. Also, plants in close proximity to pavement lose water quickly, when compared to plants adjacent to cool pavements. In addition to positive air quality impacts (carbon, VOC’s, temperature, etc.), water conservation is a good reason to look at new resin based paving technology. This will be explored here through a case study of a project in Northern California: Lake Merritt located in the middle of Oakland, CA.