Agenda - Planning Commission - 01/31/2013 - Special

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storm sewers). Pervious pavement can also be allowed, or even required, for parking areas to promote on -site infiltration. To illustrate, in 2011 Los Angeles adopted an LID ordinance requiring that the first 0.75 inch of rainfall be captured on -site (Ordinance No. 181899). The city also provides information on best practices such as rain barrels, permeable pavement, planters, rain gardens, and dry wells through its Stormwater Program (Los Angeles 2012). Another approach to encourage the reuse of water is requiring that developers install dual pipe systems to allow for the use of nonpotable water for irrigation purposes. A secondary pipe (sometimes called a purple pipe) is used to transport this water in a parallel system separate from the potable water. For example, Windsor, California, requires the installation of purple pipe for landscape irrigation purposes 012-7-105). 3. Be Cool Cooling down buildings, parking areas, and other surfaces that tend to absorb heat from the sun can help reduce energy usage —particularly in climates dependent on air conditioning. Trees, landscaped open space, and landscaped (green) roof areas can help reduce the heat island effect and maximize pervious surfaces in urbanized areas, and zoning codes can play a particularly important role in promoting pervious surfaces. Trees can play a major role in lowering both site -specific and aggregate ambient air temperatures, and many communities have incorporated tree planting and preservation requirements into their zoning codes. Another effective technique is to require that a certain minimum percentage of a paved parking area is shaded. Rancho Cordova, California, uses this approach (§23.716). Black asphalt absorbs light (and heat), resulting in 57 percent more electricity use than lighter colored concrete (Adrian and labanputra 2005). Requiring highly reflective surfaces (i.e., those with a tight color high-albedo index of at least 29) for roofs, parking areas, streets, and other paved areas increases the efficacy of artificial lighting and can reduce heat island effects. California's green building code, CalGreen, includes provisions requiring that buildings and paved areas have a certain solar reflectance to minimize heat gain if they are not shaded (§A5.1o6.11.2). Austin, Texas, has similar reflectance requirements for flat roofs and also actively encourages the provision of green roofs through code incentives (Austin 2012). 4. Let the Sun Shine While the previous point focused on how to eliminate solar heat gain to lower air conditioning bills, in certain instances, maximizing solar access increases the opportunity to generate electricity or heat water with a solar energy system. Heating water accounts for 15 to 3o percent of electricity use in homes equipped with electric water heaters, and using a solar water heater can result in a 5o to 8o percent QQ Minimum parking lot shade requirements can lessen urban heat island effects. cost savings. Furthermore, many homes have space for a 4kW rooftop solar energy system, which in some circumstances can offset total annual electricity use. Consequently, some states protect the rights of property owners to receive sunlight. These solar access protections often enable property owners to use solar easements to prevent neighbors from building structures that may block solar panels, garden areas, passive solar heating, or other features that require solar access. A few states even protect solar access without a solar easement. The Database of State Incentives for Renewable Energy includes a state -by -state breakdown of solar rights and access protection laws (www.dsireusa.org). At the local level, many jurisdictions have a solar access or solar easement provisions in their development regulations. These provisions either enable the recordation of easements or establish a solar envelop by right to ensure that solar systems are not blocked or made less efficient by development on neighboring properties. Subdivision or zoning provisions can also encourage buildings and neighborhoods to be designed along an east -west access to maximize solar exposure. The percentage of homes that are positioned for optimum solar access could be specified in the code (e.g., 5o percent). This will at least provide the opportunity 25% 50% 50% 0% Notes: 1. This diagram is intended to reflect the manner in which shade is credited under various conditions. 2. Trees may receive 25%, 50%, 75%, or 100% as shown. 3. Shade overlap is not counted twice. ZONINGPRACTICE 12.12 AMERICAN PLANNING ASSOCIATION I page 4