Page 412 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

372 Cha pte r T e n

• CWP (1998), Better Site Design, Center for Watershed Protection, Ellicott
City, MD.
• DoD (2004), Unified Facilities Criteria (UFC) Design: Low Impact Development
Manual, Department of Defense, October 24.
• Hinman, C. (2005), Low Impact Development: Technical Guidance Manual for Puget
Sound, Puget Sound Action Team, Seattle, WA.
When one is developing a site, many local land development and zoning regulations
may also impact LID designs. Some common ones are listed in Table 10.1.8.
In addition to considering the items listed in Table 10.1.8, it may be helpful to keep
a list of other concepts in the engineering toolbox for site design to aid in attaining LID
goals. Many of these are listed or reiterated in Table 10.1.9.
There are several important variables used in LID calculations which are many
times also used for local zoning calculations. Table 10.1.10 summarizes several of the
common basic ones.

Zoning Requirement Meaning Applicability to LID
Minimum landscape A minimum percentage of the These areas will reduce impervious
areas lot must be landscaped areas and may also be used for
IMPs for stormwater management
such as bioretention cells
Required landscape A minimum amount of setback These areas will reduce impervious
buffers or buffer must be landscaped areas and may also be used for
between the development on IMPs for stormwater management
the site and neighbors such as bioretention cells
Minimum trees in A minimum amount of tree These areas will reduce impervious
parking areas shading is required in parking areas and may also be used for
areas IMPs for stormwater management
such as bioretention cells
Maximum slopes on For vehicular safety and access Minimizing slopes on paved
drives/paved areas reasons there are maximum surfaces decreases the flow rate
allowed slopes in paved areas of runoff
Maximum ADA For ADA access reasons there Minimizing slopes on surfaces
(Americans with are maximum allowed slopes decreases the flow rate of runoff
Disabilities Act) slopes along the accessibility route
FAR Minimum or maximum floor Balancing FARs with lowered
area ratios are sometimes impervious cover can help
established to limit either the maintain more areas on the lot
use or the land disturbance which mimic the natural hydrology
impact on the site, respectively
Minimum and Minimum parking requirements Minimizing parking areas will
maximum parking establish adequate parking for decrease impervious surfaces
the use and maximum limits
site impacts
Road/drive width There are usually minimum and Minimizing paved areas will
requirements maximum road and drive widths decrease impervious surfaces
for safety and access reasons

TABLE 10.1.8 Example Zoning or Land Development Requirements That Impact LID Design Features