Green Laws & Blue Water,
Landscape Ordinances and Storm Water

Prof. Buck Abbey, ASLA, CELA

© all rights reserved.

Robert Reich School of Landscape Architecture

Louisiana State University, Baton Rouge, Louisiana

Louisiana Water Quality Conference 2007

October 29-31 2007

University of Louisiana , Lafayette, Lafayette, Louisiana

"Abstract"

Architects, landscape architects, engineer, and interior designers have designed with life safety codes for many years. The codes set forth design standards, commonly accepted construction practices and agency requirements that must be met for all construction projects. Building codes are closely related to community zoning laws and are often found within the same set of municipal laws. Designers are required to see that construction plans are in compliance with standard building codes and contractors must build accordingly.

Landscape Architects have been working with landscape design since the late 1960’s. Standard building codes largely do not pertain to site development, land clearing, tree preservation, water conservation, storm water management or landscape construction. Building codes primarily address buildings. Landscape codes regulate site development though the police power of zoning are becoming an important aspect of land use regulations in Louisiana.

One of the newest trends in landscape code development is to include on-site storm water management standards within community landscape codes. These standards must be based in part on low impact development practices, must utilize a variety of storm water BMP’s and be designed around specific storm water design principles. These all must become a standard of practice for landscape architects and civil engineers who develop drainage plans and specifications.

“Green Laws”

An emerging way to ensure that nature in the city is cared for is to enact a comprehensive landscape code which specifies minimum standards for caring for nature in the city, especially site development, land clearing, habitat preservation, tree protection, irrigation, water conservation and on-site storm water management. In recent years, city after city across the nation have turned to this type of local planning and design public policy as a means of ensuring better site design acceptable community design, tree preservation and better landscape construction within the city. The better codes are all contained within a community’s zoning ordinance.

Landscape codes typically provide for the construction of such site facilities as parking lots, site service area, pavements, urban walls, landscape buffers, irrigation systems, visual screens, and the design of yard plantings that serve a variety of uses. In most communities, the reason for the ordinance is the protection of the public by placing land use regulations on lot compatibility, damages to natural systems, water usage, and those that provide landscape design, maintenance, arboriculture or landscape construction services. Communities are also creating standards to protect tree canopy, provide for shade, prevent storm water run off, abate erosion, and cool hot urban environments.

“Blue Laws”

While many communities enact green law ordinances merely for beauty or economic development, there are other important reasons for landscape codes to be written. In recent years Davis, California enacted a landscape ordinance for solar control, particularly in regards to parking lots. Energy from the sun is seen as resource to be harvested to provide energy for the home. Near by Irvine, California, enacted an ordinance to promote sustainability that is a form or recycling natural resources and reducing the reliance upon energy resources. Santa Monica, in Los Angeles, county is concerned with rainfall. Santa Monica is known as the ‘sustainable city’ and recovers all rain that falls that on the city to recaptures pollutants before they find their way into Santa Monica bay. All rain water 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 be harvested and recycled so they base their ordinances on the need to conserve natural stores of fresh water. These communities understand it is 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 on on-site storm water facilities.

Some of the new Georgia codes are directed toward sustaining tree canopy, preventing soil erosion and allowing rain water 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. Louisiana is exploring on-site storm water management and green parking lot design. In the Carolinas tree codes are being written to provide for certain stated 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 utilized for storm water management as well.

In Louisiana, the Hammond landscape code is the first landscape code to address on-site storm water management. The Hammond code requires a degree of storm water management not seen in other Louisiana communities. This ordinance has been enacted to comply with the Environmental Protection Agency and Louisiana DEQ mandates to reduce non-point 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. .

Waterways, fifty (50) feet in width along both banks of natural streambeds, riverbanks and drainage canals maintained by the parish and measured from the mean high water line must be undeveloped and maintained in its natural forested condition. In addition the Hammond code suggests where possible, and at the discretion of the city building department, a portion of the drainage from the parking areas shall be drained through deep-rooted perennial ornamental grasses within swales in the road frontage landscape strip.  Based upon lot size, site conditions, and parking requirements, parking tiers shall be separated by a minimum three (3) feet of landscape filter areas. Landscape filter areas are to include a groundcover and landscape material that will achieve one hundred (100) per cent coverage when mature. Examples of plant materials that can be used for this purpose include turf grass sod, monkey grass (Ophiopogon japonicus), liriope (Liriope muscari), Japanese ardesia (Ardisa japonica), Asian jasmine (Trachelospermum asiaticum) , or iris (Iris Hexagonae species series and hybrids, Iris pseudacorus). Parking spaces that exceed the minimum number required by the Hammond Zoning Ordinance are not required to be hard surfaced but can be paved with porous paving that will allow the infiltration of water.

Recently New York City adopted similar regulations as part of Mayor Blumberg’s PlaNYC Sustainability Plan for America’ largest city. To make New York sustainable into the future, Article II, Chapter 5: Accessory Off-Street Parking and Loading Regulations of the 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 landscape code requires The open parking area shall be graded to allow stormwater runoff to drain into all planting islands and perimeter landscaped areas. Planting islands shall have an inverted slope to allow a minimum six inches and a maximum of one foot of stormwater ponding, and surface ponding must drain in at least 24 hours. To allow for adequate drainage, elevated catchbasins shall be placed in the planting island above the ponding level. 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 shall be 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. A raised curb shall edge the planting island, shall be at least six inches in height and shall contain inlets at appropriate intervals to allow stormwater infiltration from open parking areas.

The Chapel Hill, North Carolina landscape ordinance is an example of how tree ordinances, landscape codes and storm water management can all be part of site design. Chapel Hill’s ordinance is based upon integrating the tree and landscape code into the zoning ordinance in the form of site design standards. These standards including regulations for critical areas, habitat preservation (especially of ‘significant stands’), tree care, tree protection, landscaping, screening, buffering, parking lot design, open space, integrated management practices, lighting, storm water management and erosion/sedimentation control. They are all part of the zoning code.

Fulton County, Georgia’s tree law mentions control of soil erosion, moderation of storm water runoff, improved water quality, interception of airborne particulate matter and the reduction of air pollutants as major design requirements. Enhanced wildlife habitat is also mentioned as are the reduction of noise and glare, climate moderation, aesthetics, scenic quality and increased property value.

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 and Virginia have recognized the same problem for over a decade so their local codes call for forest preservation.

The Louisiana Department of Environmental Quality is in the process of crafting a model landscape code for use in Louisiana towns and cities that must meet Phase II storm water requirements. The model code is available to Louisiana communities who care to enact landscape regulations and on-site storm water management regulations into their community zoning code within their current landscape code.

LDEQ Model Storm Water Code

The storm water design requirements of a well-crafted landscape code must address several factors. As a minimum they must include statutory authority and applicability to local zoning and land use planning procedures that meet the storm water needs of a community. These ordinance will generally set minimum control requirements, provide a range of design criteria, and recommend the design of stormwater BMP that are adapted to local rainfall amounts and local soil conditions. Figure 1. as seen below provides the recommended BMP’s as storm water management measures that will work the best in local Louisiana landscape codes.

Whichever BMP’s are selected, be they structural or non-structural they all should include the planting of native vegetation. Therefore, this is the principal reason local stormwater regulatory requirements should be housed in the community landscape code and not the local drainage code. The later is concerned with centralized storm water systems and landscape codes are more suitable for the design and construction of de-centralized, on-site storm water facilities.

Finally it is important that the storm language within a community be written to require the preparation of on-site storm water plans and details that can be reviewed and approved by local public works agencies prior to being given to landscape contractors for site construction. Many states have Storm Water Design Manuals that assist designer’s with the preparation of storm water plans, details and specifications. Louisiana does not.

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Projects Smaller Than One Acre in Size

Micro-detentions (Rain Gardens)

Vegetative Swales (Bioswales)

Planted Storm Water Buffers

Planted Parking Lot Interiors (with reverse crown planting beds)

Storm Water Groves (Natural Forest Floor Preserved)

Infiltration Trenches (French Drains)

Parking Lot Detentions (Both Interior and Exterior)

Natural Wetland Preservation

Porous Paving (Green Parking)

Projects over One Acre May Also Include

Disconnected Roof Tops

Disconnected Parking Lots

Dry Ponds (Detentions)

Wet Ponds (Retentions)

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Fig. no. 1-Louisiana Storm Water BMP’s for Site Development

Since permitting is a common practice associated with landscape plans this too needs to be part of a local on-site storm water ordinance. Permits get issued, inspections are made and landowners are often required to post a bond or sign a permanent maintenance agreement to ensure upkeep of the storm water facilities. Should annual maintenance not be undertaken and the storm water system fails to perform as designed, the permit can be suspended and site occupancy can be revoked until corrections are made. Other penalties are possible.

And of course there will be permit fee to cover the cost of plan review, inspection and administrative activities by the local department of public works or landscape and forestry office. An of course all well crafted landscape codes make a provision for definitions, appeal, severability and effective date. Figure 2 is an outline for the Louisiana Model Landscape Code on-site storm water management ordinance.

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Sec. 17.1 Recitals, Purpose & Intent

Sec. 17.2 Applicability of Landscape Requirements

Sec. 17.3 Definitions

Sec. 17.4. Landscape Design, Irrigation and Storm Water Management Standards. ¹

Sec. 17.5. Landscape, Irrigation & Storm Water Plan Requirements

Sec. 17.6. Alternative Compliance

Sec. 17. 7. Administrative Procedures, Permits and Inspection Requirements

Sec. 17. 8. Administrative Guidelines & Design Manual. ²

Sec. 17.9. Penalty For Violation of Part

Sec. 17.10. Enforcement and Appeal

Sec. 17.11. Director & Staff (Public Works, Tree and Landscape Commission)

Se. 17.12. Part Supplementary to Other Ordinances

Sec. 17.13 Conflicts

Sec. 17.14. Severability

Sec. 17.15. Effective Date

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1. Contains Storm Water Best Management Practices and Design Criteria

2. State Storm Water Design Manual

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Fig. no. 2 -Louisiana Storm Water Model Landscape Code Outline

On-Site Storm Water Design Principles

Natural methods of storm water management in urban areas should based upon principles of low impact development are cost-effective and provide additional benefits, such as load reduction, increased aesthetics and economic value, reduced maintenance, sustainable natural resources, and preservation of local heritages. Local zoning laws provide guidance and regulation to developers. Landscape codes within zoning dictate how the landscape should be designed, and, if crafted properly, could recognize Louisiana’s need for managing high volumes of storm water runoff, sedimentation and flooding. A model landscape code such as the LDEQ Model crafted to include both landscaping and on-site storm water management standards is a new tool for city planning agencies that oversee development and construction. The code addresses land clearing, tree preservation, site planting, parking lot design, sediment control during construction, irrigation, water conservation, low impact development procedures, and on-site storm water control for new and redeveloped projects, which are permitted under the general rules of zoning law.

The design of small on-site storm water facilities is important for dealing with water quality problems in Louisiana. Recent studies conducted on behalf of LDEQ by the author have formulated several principles that should be incorporated into any community storm water based landscape code. Now these principles need testing under project implementation conditions but for now they are worth thinking about when crafting a community storm water based landscape code. The principles can be seen in Figure no. 3. Several of them are in need of comments as a conclusion to this paper.

First. It is important that decentralized storm water management become a part of all site design for projects large and small. This will be best accomplished as part of the landscape plan approval procedure that the local landscape code requires as mentioned above. Secondly, each community must prepare historical local storm water data that must be used as part of the design process and calculations that are necessary for the preparation of storm water plans and BMP details. Data is needed for intensity, duration and frequency of storms of a much finer calibration than commonly found associated with tables used with the Rational Method of computing storm water flow. Ultimately, each community will have to settle upon two important storm water principles directly related the character of storms. That is a local “design storm” volume and required “capture percentage” of that storm that must be disconnected, captured, stored, filtered, infiltrated, evaporated, and evapo-transpirated on the site where it falls.

Preliminary studies by the offer seem to indicate that in Louisiana on average from South to North in Louisiana that a design storm of 11/2” in which forty (40) percent is managed on site are workable numbers. If the rooftop and the parking lot of each development is disconnected from down slope flow, it is quite possible to raise this capture percentage to sixty (60) percent of total design storm volume. Parking lot detentions and roof top water recycling into irrigation systems are two methods of capturing and keeping storm water where it falls along with any non-point pollutants that might originate there.

Thirdly, each community must decide what is the appropriate “permeability ratio” for every development site and land use category in its community zoning ordinance and incorporate this standard into their municipal code. A reasonable permeability ratio is thirty (30) percent of site area. Without this minimum amount of open space set aside and dedicated to storm water management and planting it will be impossible to design storm water BMP’s to meet the capture percentage of the design storm. Therefore the three most important principles include the design storm, capture percentage and permeability ratio. The other principles can be studied in detail in Figure 3.

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Twelve On-site Storm Water Management Principles

For Louisiana

Total Site Area (TSA) of any zoned lots will consist of development, vegetative areas and on-site storm water management facilities.

Landscaped Areas (LA) become micro storm water management facilities.

Rear and Side Buffers for storm water management, planting and screening comprising 30 percent of total site area. (TSA x .30).

Street Yard Buffer of a minimum of 78% percent of required front yard set back width. (SYB / .78).

Total Side Buffer Width to meet zoning standards of a minimum of 6 percent of property width (PW X .06).

A Permeability Ratio (PR) between total site area and permeable open space of at least 30 percent. (TSA x OS= .30) to a maximum of 54.3 percent.

Vehicular Use Area (VUA) used for cars, planting and storm water management shall containing a minimum of 12.3 percent permeable planted area.(VUA X .123).

Street Wall Planting Areas (SWPA) sized for building façade enhancement and roof top run off collection of a minimum width of 2/10 the height of the building. (BH X .20).

Stream Bank Buffers (SBB) or Water Front Yards (WFY) of a minimum depth of 50 percent of stream width. ( SW x .50 stream width) (WFY x .50 stream width).

BMP’s Storm Water BMP’s recommended by the EPA consisting of bio-swales, planted buffers, grassed swales, sand filters, micro-detentions, infiltration trenches, irrigation cisterns, storm water chambers, and porous paving.

Capture Percentage (CP), 40% of design storm rainfall volume.

Design Storm (DS) , 11/2 inches of rainfall per hour intensity.

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Fig. no. 3- On-Site Storm Water Design Principles

Conclusion

The primary purpose of the LDEQ model landscape code is to solve problems of community site development and design that presently allow property developers to increase the amount of storm water run off and it attendant non-point pollution into public conveyance systems and then into fresh water bodies.

This model landscape code is a site development friendly method that will encourage developers to landscape their development sites in combination with non-structural storm water best management practices in such a way as to maintain existing run off rates at predevelopment levels while at the same time adding to the visual appeal of the property though the use of landscape plants and design.

This method of site construction favors nature and works to utilize natural methods for controlling site development impacts while at the same time reducing development costs. LID principles driving the development of this code include a) better site design, b) minimization of impervious surfaces, c) protection of natural drainage features and existing tree vegetation, d) reduce land disturbance activities, e) promote low maintenance landscaping that reduces the use of herbicides, fertilizers, pesticides and lawn grass, f) protect stream banks and lake edges, and g) reduce storm water ‘time of concentration at site outfalls.

The emphasis of the LID storm water best management practices in this code is on the use of non-structural storm water best management practices (BMP’s) as defined by the Environmental Protection Agency. Non-structural methods, which also can be called ‘micro-methods’ of storm water management, are best used on small parcels of land where available space is limited and decentralized drainage is practical and efficient. This is often the case in the city and suburban fringe where landscape codes are utilized for better land use practices and site design performance on small sites generally less than five (5) acres in extent. Non-structural methods do not use complicated engineering formulas to calculate water flow and capture and release. Calculations are simply based on computing water storage volume according to the design storm capture ratio. Non-structural methods are designed according to the principle that trapping rainwater where it falls, or close to where it falls, where storm water capture volume meets or exceeds rainfall.

These micro-methods of storm water management rely upon ground shaping, surface material selection and vegetation plantings to modify the infiltration capabilities of grassed landforms, beds and planted buffers. These earth friendly methods that replicate nature’s methods of storm water management make it easy for landscape architects, engineers or contractors to design site facilities to better detain, retain and infiltrate storm water. Landscape design practices also make it easy for landscape contractors who build and plant project sites to manipulate ground surfaces to capture rainfall.

In the near future in Louisiana, landscape administrators, landscape architects and civil engineers and architects will need to know more about on-site storm water management and how developers must comply with Phase II NPDES rules, erosion control BMP’s, green parking lot design science and a host of topics concerning urban horticulture, irrigation water distribution and reuse and on site storm water management techniques.

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BACKGROUND READING ON GREEN LAWS

Abbey, D.G. Buck, "Green Laws, Building Landscapes In The Twenty-first century". Proceedings 1999 ASLA Annual Meeting, American Society of Landscape Architects, Washington D. C.. 1999.

Abbey, D.G. Buck, "Green Laws In Three Communities". Proceedings 2003 National Urban Forest Conference, American Forest, Washington D. C.. 2003.

Abbey, D.G. Buck, "U.S. Landscape Ordinances". John Wiley & Son, Inc., New York, NY. 1998.

Abbey, D.G. Buck, "Guide To Writing A Landscape Ordinance". Louisiana Association of Nurserymen, Baton Rouge, LA. 1988.

Abbey, D.G. Buck, "Guide To Writing A City Tree Ordinance". Louisiana Association of Nurserymen, Baton Rouge, LA. 1993.

Bernhardt, E.A. and Swiecki, T.J., Guidelines for Developing and Evaluating Tree Ordinances, California Department of Forestry and Fire Protection Urban Forestry Program, Sacramento, CA. 1991.

Bowen, C., Landscape Ordinances: To Define and Protect, Zoning Practice, American Planning Association, April 2004.

Fazio, James., How To Write A Municipal Tree Ordinance, Bulletin No. 9. National Arbor Day Foundation, Nebraska City, Nebraska. 1991.

Garber, Melvin., Components of a Tree and Landscape Ordinance, University of Georgia, November, 2000.

Duerksen, Christopher. J., Richman, Suzanne, Tree Conservation Ordinances, PAS Report Number 446, American Planning Association, Chicago, Il. 1993.

Moll, Gary, Ebenreck, Sara., Shading Our Cities, Island Press, Washington D.C., 1989.

Robinette, Gary, O. "Local Landscape Ordinances." Agora Communications, Plano, Texas, 1992.

Wolfe, K.L., Trees, Parking and Green Law: Strategies For Sustainability, College of Forest Resources, University of Washington, Seattle, WA. 2004

__________________., International Zoning Code, International Code Council Inc., Country Club Hills, IL, 2002.

WEBOGRAPHY NOTES

1..The Landscape Ordinance Research Project at Louisiana State University has conducted studies of landscape and tree laws since 1987. Visit their web site that provides useful information about community landscape codes, code vocabulary, design components, and technical standards. Visit LSU at www.greenlaws.lsu.edu.

2.. Visit the LDEQ Splash-Splash Storm Water web site at www.abbey-associates.com/splash-splash

Biography

Prof. D.G. Buck Abbey is Associate Professor of Landscape Architecture at the Robert Reich School of Landscape Architecture at LSU and Principal of the Louisiana, landscape architecture - planning firm, Abbey Associates, Inc.. He has taught design, construction, plant materials, professional practice, graphics and computer technology courses at LSU since 1974. Abbey received his terminal degree from Harvard University. He is a recognized authority on municipal landscape codes and is the author of the book, U.S. Landscape Ordinances. This book published by John Wiley & Sons, Inc. Publishers in 1998 has several awards. He provides consulting services on landscape codes and site planning nationwide. He is Associate Editor and writes a montly column for Landscape Architect & Specifier News Magazine in Tustin, California.

Abbey maintains a research web site at LSU on the subject of landscape, tree and land alteration ordinances. The site provides assistance to anyone seeking help with writing landscape codes, tree preservation laws and land development code. The site can be visited at www.greenlaws.lsu.edu/

Parts of this paper were made in a presentation in Florida in January 2005 and in Charlotte, North Carolina in 2006 and published with the meeting papers of the 2005 Louisiana Surface Water Conference, University of Louisiana, Lafayette, Louisiana. This work has been made possible in part by grants from the USDA Forest Service, Urban and Community Forestry Program of the Louisiana Department of Agriculture And Forestry , The Louisiana Department of Environmental Quality and Environmental Protection Agency, and the Florida Chapter of the International Society of Arboriculture (ISA). (Green Laws & Blue Water V3, Final)