Site Design Measures/Low Impact Development
Site design measures are site planning approaches aimed at either preventing or reducing adverse impacts of stormwater pollutants and increases in peak runoff rate, volume and duration on water quality and beneficial uses. Site design measures include techniques such as protection of natural resources and/or reduction of impervious surfaces used when planning the layout of a development or redevelopment project. Typical site design measures include protection of natural resources, reduction of impervious surfaces, incorporation of detention areas in landscaping, pervious paving, green roofs, and directing roof downspouts to drain to landscaped areas. All of these measures help to protect water quality by filtering stormwater through plants and soil and allowing stormwater to infiltrate into the ground, thus mimicking the natural dydrology of the undeveloped site. The inclusion of site design measures within a project may also reduce the size of treatment and/or hydromodification management measures required for the site.
The Program has developed the following reports and work products which discuss the inclusion of site design measures in new development and redevelopment projects. Other useful technical reports which discuss site design techniques are included on the list.
C.3. Stormwater Handbook
Since its development in 2003, the C.3 Stormwater Handbook has been the main document used by Co-permittees to efficiently and effectively implement NPDES Permit Provision C.3. It consists of a compilation of various tools and work products used to help mitigate the potential impacts of new projects and redevelopment projects on stormwater quality and quantity. The C.3 Stormwater Handbook is updated periodically. In May 2006, the handbook was updated to include revisions of C.3 adopted in 2005.
Site Design Guidebook
In 2004, the Program completed a document entitled Developments Protecting Water Quality: A Guidebook of Site Design Examples (Guidebook) that provides information on local projects or areas where innovative design measures which protect water quality have been applied. The Guidebook was updated to include additional examples in February 2007.
Site Design Awards Program
Since 2006, the Program has offered a Site Design Awards Program to recognize Santa Clara Valley's public agency and private development community leaders who are solving site design challenges, reducing stormwater pollution and runoff quantity and meeting the requirements of the municipal NPDES permit. Applications for Site Design Awards also help provide additional site design examples for inclusion in the Site Design Guidebook. Past award winners are described in a series of fact sheets.
Site Design Dialogues
The Program, in conjunction with the SCBWMI Land Use Subgroup, hosted four dialogues (October 8, October 29, November 12 and December 10, 2003) to explore the underlying issues that may lead to potential conflicts when incorporating better site designs from a water quality perspective. Each meeting involved identifying potential conflicts; a better understanding of the underlying issues surrounding the conflicts, brainstorming possible solutions that could help resolve the underlying issues; and identifying additional stakeholders (e.g., city departments, citizen groups) that should be involved in the discussion.