Freiburg is known as an ecocity. The newly built neighbourhoods of Vauban and Rieselfeld were developed and built according to the idea of sustainability. The citizens of Freiburg are known in Germany for their love of cycling and recycling.

This past December, as climate talks in Copenhagen commenced, I sat in talks in Istanbul listening to local government representatives, building professionals and academics discuss concrete actions that can and have been taken to reduce greenhouse gases in cities around the world. The 8th annual Ecocity World Summit posed a compelling alternative to the fights and frustrations that mired the climate talks of Copenhagen in conflict. Cities represent about 75% of greenhouse gas emissions worldwide, and the birth of the “eoocity” concept a few decades ago may have marked the beginning of our most tangible solution yet. From recycling, wastewater treatment and green building to smart urban planning, public transit and renewable energy generation, ecocity plans and ideas have emerged with a list of seemingly “no-brainer” action items to pursue.

While in theory, the “ecocity” may seem like a very straightforward concept, in practice the challenges prove tough to transcend. The urban and suburban sprawl that plagues regions in the United States, Canada, Australia, and New Zealand may seem like an almost insurmountable barrier to reducing carbon emissions. However, in Istanbul, a city of 13 million and growing, sprawl is compounded by the fact that much of the development is unplanned. This is also true for other mega-cities like Rio de Janeiro where families often add stories to their own homes, creating unsound structures that may collapse during natural disasters. Such unplanned settlements also make it difficult to create underground tunnels for a metro system, as there may be no record of where gas and electricity lines run underground. Traffic and a lack of environmental practices like wastewater treatment are also a major issue for such megacities.

Historical considerations also present challenges, as the rich cultural heritage of ancient cities demands a certain authenticity of design. Moreover, as cities like Istanbul go to dig tunnels for eco-features like an underground metro, they may discover archeological treasures that force them to stop digging.

In modern cities of intense density like Hong Kong, Tei Pei, and Singapore, a lack of space to erect renewable power generation and urban farming operations create challenges to meeting energy and food demands without importing food and energy. In many developing nations, a lack of laws to regulate pollution and a lack of enforcement for existing environmental laws also create little incentive to move towards renewable energy. Some regions lack the resources to produce renewable energy, forcing them to make a decision between a local energy economy and a clean energy economy.

Approaches to creating an ecocity to solve these problems vary. According to Elizabeth Rapoport of the University College of London, there are three main categories of ecocities. Ecovillages, such as Cerro Gordo in the U.S. are small pastoral communities. Masterplanned ecocities such as Tianjin, China and Masdar, Abu Dabi, are new cities that incorporate ecological principles from day one. Models in already retrofitted ecocities like Curitiba, Brazil and Freiburg, Germany have the greatest potential to transform the already developed world, where builders and planners will have to make improvements on the existing infrastructure and building stock. Taking lessons from other more advanced cities will be an important step in the process if cities want to avoid reinventing the wheel. Conversely, avoiding some of the mistakes that more established cities have made will be crucial for nascent cities in the developing world.

The term “ecocity,” like other trendy terms including “green” and “sustainable” will likely be the subject of abuse over the coming years and decades. While there is no one-size-fits-all solution for the cities of the world, the sooner the international community comes together to define an ecocity that really does live up to the name, the more clear direction and success cities will have in reducing greenhouse gas emissions and pollution while improving the quality of life for their residents. Hopefully the local governments involved in redesigning our cities can learn to work together more effectively than did the participants in Copenhagen. Unfortunately, that’s a low bar.

A solar thermal power plant that uses a tower.

Recent disputes over water use in deserts that are well suited for solar thermal power plants have illustrated the need for a holistic approach to urban needs. Solar thermal plants use cheaper technology than photovoltaics (solar panels), but require substantial water because mirrors heat a liquid to create steam that drives an electricity-generating turbine. Similar to a fossil fuel power plant, the steam must be condensed back to water and cooled for reuse. Typically this happens in a cooling tower and requires constant replenishment of water as the excess heat and water evaporates. Alternatively, dry cooling can be used, but requires fans and heat exchangers and is much more expensive.

The American Southwest is currently the site of plans for dozens of multibillion-dollar solar power plants on thousands of acres of desert. In California, solar developers have already been forced to switch to less water-intensive technologies when local officials have refused to give up water. Furthermore, some large solar projects are currently tangled in conflicts with state regulators over water consumption.

Considering the effects of power generation on the ability to provide water for a community will be crucial as water becomes even scarcer and renewable power projects burgeon to replace fossil fuel production.

Using low-carbon technologies that are not water-intensive combined with smart city planning and sound water use policies will help cities to avoid water disputes among stakeholders. Cities around the world have already implemented rainwater harvesting policies to help address water shortages by simply catching and using the rainwater that is currently diverted into storm drains – and ultimately, into the ocean. Moreover, California implemented a new policy at the beginning of 2009 to allow the installation or alteration of a clothes washer greywater system to be exempt from a construction permit that was previously required. Greywater systems allow a household to irrigate a landscape with recycled water.

Employing green rooftops and community gardens in dense cities and maintaining substantial surrounding open space is a strategy for water conservation as well because the less paved or impermeable surfaces exist, the less urban runoff occurs and the more ground water can be recharged. Furthermore, water use intensity is greatly affected by population density. According to the Sierra Club’s Challenge to Sprawl, three households per residential acre (typical suburban sprawl) on average equates to 1,032 gallons of water used per household per day. Conversely, 100 households per residential acre on average equates to 192 gallons of water used per household per day

Such policies will relieve pressure when citizens take advantage of them to conserve and they mean greater efficiency in the use of resources. Policies that force vital human services (such as power production and delivery of water) to compete for the same resources are unlikely to succeed. Moreover, the monetary and environmental cost of water projects like desalinization is substantially higher than simply allowing citizens to catch rainwater or irrigate with recycled water. Thus, tax payer dollars are better spent when policies support sound urban design and resource conservation.

Several city planning and policy experts will be addressing the issue of water use in cities at the upcoming EcoCity World Summit in Istanbul this December. Presenters will include Richard Register of EcoCity Builders, Walter Hood (urbanist, landscape architect), Ken Yeang (bioclimatic design), David Hall (New Vista Ecocity), the World Bank Eco2Cities program, Global Footprint Network, Janet Larsen of Earth Policy Institute (representing Lester Brown’s Plan B), and Brent Toderian, head of City Planning for City of Vancouver, Canada and author of the EcoDensity Initiative.

Photo: “IWS - watercache.com”; 5600 gallon commercial rainwater collection system for LEED Gold rated fire station in Denton, Texas. Rainwater is used to irrigate native plant landscaping around the station.

As battles over water rights rage and profligate water usage continues in many places, policy makers will have to find tools to lead communities towards more responsible water management.  One such policy tool is an ordinance to encourage or even require rainwater harvesting.

The best rainwater harvesting policies protect water as a human right, protect public health and promote sustainability. Through a combination of incentives, taxes and penalties, meaningful water conservation can be achieved.

Restrictive policies can create barriers to implementation and add unnecessary costs, but well-designed policies will encourage rainwater harvesting and help to maximize the benefits of implementing these systems. When developing a rainwater catchment policy or ordinance, consider the following criteria.  Your policy or ordinance should be:

•    Economically viable and ecologically sustainable
•    Achievable and measurable
•    Easy for the public to understand and simple to implement with streamlined processes
•    Reviewed by actual rainwater harvesting professionals
•    Include education and technical training for the public, staff and elected officials
•    Include financial support such as subsidies or grants for low-income communities

Semantics are also important to consider.  How you define rainwater can greatly affect outcomes.  Avoid classifying rainwater as stormwater, runoff, greywater or wastewater.

Hundreds of thousands of rainwater harvesting systems exist throughout the world.  While in many places in the U.S. rainwater harvesting is actually banned because of “first come, first serve” laws dating back a century, a few American cities actually require that new buildings use cisterns to store roof runoff.

Legislation around the U.S.:

Tucson, Arizona: In October of 2008, the city of Tucson, Arizona became the first municipality in the country to require developers of commercial properties to harvest rainwater for landscaping.  The new measure – approved by a unanimous vote by the City Council – requires that new developments meet 50% of their landscaping water requirements by capturing rainwater. The new rule goes into effect June 1, 2010.

Santa Fe County, New Mexico: Residences with 2,500 sq ft or more area must install an active rainwater catchment system comprised of cisterns. All commercial developments are required to collect all roof drainage into cisterns to be reused for landscape irrigation.

Albuquerque and Bernalillo County, New Mexico: Residences with 2,500 sq ft or more area must install an active rainwater catchment system comprised of cisterns. All commercial developments are required to collect all roof drainage into cisterns to be reused for landscape irrigation.

State of Texas: In 2001, the Texas legislature amended the Texas Tax Code to allow taxing units of government the option to exempt from taxation all or a part of the assessed value of the property on which water conservation modifications have been made.

City of Austin, Texas: The residents of the city of Austin can buy rain barrels at subsidized rates and also they can claim a rebate for the installation of approved cistern systems. Commercial/industrial properties can collect rebates up to $40,000 for the installation of rainwater harvesting and Grey water systems.

City of San Antonio, Texas: The San Antonio Water System’s (SAWS) will give up to 50% rebate on the cost of new water-saving equipment, including rainwater harvesting systems, to its commercial, industrial and institutional customers. Rebates are calculated by multiplying acre-feet of water conserved by a set value of $200/acre-foot.

State of Arizona: The Government announced a one-time tax credit of 25% of the cost of water conservation system (the maximum limit is $1,000) for its residents. The water conservation system is defined as any system, which can harvest residential grey water and/or rainwater. The builders are eligible to get the tax credit up to $200 per residence unit constructed with a water conservation system. Any citizen in this state who has purchased a water harvesting system on or after January 1st, 2008, can apply for the Arizona tax credit. There is roughly $250,000 per year allocated for these tax credits.

Legislation around the world:

Mumbai, India: The state government has made rainwater harvesting mandatory for all buildings that are being constructed on plots that are more than 1,000 sq m in size.

New Delhi, India: Since June 2001, the Ministry of Urban affairs and Poverty Alleviation has made rainwater harvesting mandatory in all new buildings with a roof area of more than 100 sq m and in all plots with an area of more than 1000 sq m, that are being developed.  Furthermore, the Central Ground Water Authority (CGWA) has made rainwater harvesting mandatory in all institutions and residential colonies in notified areas (South and southwest Delhi and adjoining areas like Faridabad, Gurgaon and Ghaziabad). This is also applicable to all the buildings in notified areas that have tubewells.

Haryana, India: Haryana Urban Development Authority (HUDA) has made rainwater harvesting mandatory in all new buildings irrespective of roof area.

Himachal Pradesh, India: All commercial and institutional buildings, tourist and industrial complexes, hotels etc, existing or coming up and having a plinth area of more than 1,000 square meters will have rain water storage facilities commensurate with the size of roof area. No objection certificates, required under different statutes, will not be issued to the owners of the buildings-unless they produce satisfactory proof of compliance of the new law. Toilet flush systems will have to be connected with the rainwater storage tank. It has been recommended that the buildings will have rain water storage facility commensurate with the size of roof in the open and set back area of the plot at the rate of 0.24 cft. Per sq m of the roof area.

Bangalore, India: In order to conserve water and ensure ground water recharge, the Karnataka government in February 2009 announced that buildings, constructed in the city will have to compulsorily adopt rain water harvesting facility. Residential sites, which exceed an area of 2400 sq ft (40 x 60 ft), shall create rain harvesting facility according to the new law.

Victoria, Australia: Since July 2005, new houses and apartments in Victoria must be built to meet the energy efficiency and water management requirements of the 5 Star standard, which requires either a rainwater tank for toilet flushing, or a solar hot water system.

South Australia: New homes are required to have a rainwater tank plumbed into the house.

Syndey and New South Wales, Australia: The BASIX (Building And Sustainability Index) building regulations call for a 40% reduction in mains water usage. In order to meet the BASIX target for water conservation, a typical single dwelling design must include a rainwater tank or alternative water supply for outdoor water use and toilet flushing and/or laundry, among other water conservation devices.

Gold Coast, Australia: Construction of 3,000-litre (800-gallon) rainwater tank is mandatory in the Pimpama Coomera Master Plan area of Gold Coast. This is for all homes and businesses centers connected to the Class A+ recycled Water system (those approved for development after 29 August 2005). The tank should be plumbed to their cold-water washing machine and outdoors faucets.

Queens land, Australia: Residents can get a rebate of up to $1,500 for the purchase and installation of home rainwater storages.

Germany: Rain taxes in Germany are a great example of internalizing externalities for a more fair system.  Fees are collected for the amount of impervious surface cover on a property that generates runoff directed to the local storm sewer.  That means that the more the rainwater is caught and conserved, the less rainwater runs off and is added to the storm drains. Less runoff allows for smaller storm sewers, which, in turn, saves construction and maintenance costs at the site. Thus there is a large incentive to convert impervious pavement/roof into a porous surface.

Rainwater catchment policy has implications not only for addressing water shortages, but also for reductions in energy use and related carbon emissions, as treating water consumes a lot of energy (in California, municipal water supply and wastewater treatment systems account for about 35% of energy used by municipalities.).  As local governments begin to face mandatory emissions reductions, saving water may become a cost-effective way to shave off carbon emissions that requires little capital investment compared with other strategies.

In October of 2008, the city of Tucson, Arizona became the first municipality in the country to require developers of commercial properties to harvest rainwater for landscaping.  The new measure – approved by a unanimous vote by the City Council – requires that new developments meet 50% of their landscaping water requirements by capturing rainwater. The new rule goes into effect June 1, 2010.

While environmentalists had pushed for a 100% requirement, the city chose the 50% requirement after developers expressed concern that a higher percentage would have required the installation of expensive cistern systems.

The ordinance will reduce stormwater runoff, said Brad Lancaster,a nationally recognized rainwater-harvesting expert who lives in Tucson. Lancaster said he hopes the new Tucson ordinance will inspire other municipalities to follow suit.

Members of the development community – which was represented in the stakeholder group convened by the City Council to work out recommendations for a rainwater harvesting ordinance – were supportive.

Councilman Rodney Glassman said the popularity of the measure is due to the inclusiveness of the process that created it. Before drafting the ordinance, the Council convened the stakeholder group, which included interests representing builders, developers, environmental groups and others, to work out a proposal that would be acceptable to the community.

Tucson also offers tax incentives to encourage residents to use rainwater harvesting. Other local governments, including Santa Fe and Albuquerque, N.M., require new homes to use rainwater harvesting, but not commercial properties. Today, rainwater harvesting is mandatory in places like Bermuda, parts of Australia and New Zealand, and there is a thriving rain catchment industry in Texas, Hawaii, Arizona, California and Oregon.  In water-scarce regions where fish populations have been decimated and are on the verge of extinction, there are no excuses for ignoring this effective conservation technique.

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