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Green Laws & Blue Water

By Buck Abbey, ASLA, School of Landscape Architecture, Louisiana State University, and LASN associate editor




Irvine, in Orange County, Southern California, enacted their landscape ordinance to promote sustainability.
Photo by Guy Nelson
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Green Laws--An emerging way to ensure that nature in the city is cared for is to enact a comprehensive landscape code that specifies minimum standards for that care. In recent years, city after city across the nation are taking an interest in on-site storm water management as a component of community landscape codes.

Landscape codes typically provide for the planting of specific areas of a building site and, to a lesser extent, construction of such site facilities as parking lots, site service areas, pavements, urban walls, landscape buffers, irrigation systems and visual screens that serve a variety of uses. In most communities, the reason for the ordinance is the protection of the public, health, safety and welfare by placing land use regulations on lot compatibility, damage to natural systems, regulation on those that provide landscape design, maintenance, arboriculture or landscape construction services. Community green laws are also creating standards to protect tree canopy, provide for shade, prevent storm water run off, abate erosion and cool hot urban environments.






Chapel Hill, North Carolina ordinances provide design standards for habitat preservation, tree protection, landscaping, screening, buffering, parking lot design, open space, lighting, storm water management and erosion/sedimentation control.


"Blue Laws"

While many communities enact green law ordinances merely for beauty or economic development, there are other important reasons for written landscape codes. Over two decades ago, Davis in California's Central Valley enacted a landscape ordinance for solar control, particularly in regard to parking lots. Energy from the sun is of course a resource just waiting to be harvested. Irvine, in Orange County, Southern California, enacted their landscape ordinances to promote sustainability, a form of recycling natural resources and reducing the reliance upon energy resources. Santa Monica, in Los Angeles County is concerned with rainfall. Santa Monica, known as the "Sustainable City," recovers all rainfall to capture pollutants before they find their way into Santa Monica Bay. All rainwater falling in this community is harvested and cleaned of pollutants.

Many communities in Florida, such as Lake Mary and St. Lucie County, see water as a resource to harvest and recycle, so they base their ordinances on the need to conserve natural stores of fresh water. These communities understand it is a wise water policy to reuse water for landscape irrigation purposes. Collier County on the west coast and Volusia County on the east coast both require on-site storm water management and have standards that call for the design of on-site storm water facilities.

Some of the new Georgia codes are directed toward sustaining tree canopy, preventing soil erosion and allowing rainwater to filter back into the ground. These codes call for a certain density of trees on all development sites and this density provides space for storm water capture. Carolina tree ordinances are being written to establish a certain number of trees per acre. These codes are concerned with canopy standards, shade requirements and tree preservation and in each community these planted or preserved landscape area can be used for storm water management as well.

In Louisiana, the small community of Hammond, just northwest of Lake Pontchartrain, has enacted the state's first landscape code that addresses on-site storm water management as part of the community green law. The Hammond code has been enacted to comply with the EPA and the Louisiana Department of Environmental Quality mandates to reduce nonpoint pollution of streams and waterways. This codes sets design standards for stream bank buffers, drainage filters, parking lot bioswales and the use of porous paving. In addition, the Hammond code requires that parking lot drainage flow through deep rooted perennial ornamental grasses within swales in the road frontage landscape strip. Too much water is a problem in Louisiana so the Louisiana Department of Environmental Quality is working on a model landscape code that will help clean the state's coastal waters. Maryland, Virginia, New Jersey, Florida and Washington state have recognized the same problem for over a decade so their local codes recognize storm water management.

Chapel Hill, North Carolina sets an example of how storm water management can be central to good site design. Chapel Hill's ordinance provides design standards for critical areas, habitat preservation, tree protection, landscaping, screening, buffering, parking lot design, open space, lighting, storm water management and erosion/sedimentation control.






Santa Monica, Calif. has a sustainable city plan it adopted on September 20, 1994 and updated in October of 2006 to establish sustainability targets to meet by 2010.


A Prediction

This trend is an obvious prediction for the future of all landscape codes. But even more so when the country's largest city becomes aware of on site storm water management and enacts a landscape code to require that storm water is managed where it falls.

New York City recently adopted similar regulations as part of Mayor Blumberg's program PlaNYC, a sustainability plan for America's largest city. To make New York sustainable into the future, New York City zoning resolutions now allow for the use of permeable paving, inverted crown planting beds and bioswales within parking lots.

The New York City landscape code requires open parking areas to be graded to allow storm water runoff to drain into all planting islands and perimeter landscaped areas. Planting islands are to be designed to have inverted slopes to allow a minimum six inches and a maximum of one foot of stormwater capacity. Surface water collected here must drain or infiltrate within 24 hours. Planting islands are to be constructed of soil with a depth of at least three feet measured from the surface of the adjoining open parking area. Beneath such soil, filter fabric and six inches of gravel shall be provided to ensure rapid drainage. Proper drainage rates are attained through underdrains that are connected to detention storage that meets the drainage and flow requirements of the Department of Environmental Protection or through infiltration through the surrounding soil volume. To allow for overflow, elevated catch basins are designed in the planting island in case the design storm is exceeded. A six-inch raised slotted curb is designed to edge the planting island and allow inflow.

It is my prediction that on-site storm water management will become a standard part of community landscape codes in the years ahead, and EPA Phase II storm water regulations will be phased in across the country. Green laws will make blue water.






D.G. "Buck" Abbey, Associate Professor of Landscape Architecture at Louisiana State University, is LASN's Associate Editor for Ordinances.

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June 18, 2019, 6:47 pm PDT

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