LID from Rules to Reality—The Role of the Plan Reviewer

What is Low Impact Development? This deceptively simple question was presented to a group of stakeholders during the development of Low Impact Development (LID) stormwater programs in North Carolina in 2008, and today, we have yet to get past a draft definition. Although the objectives are apparent — that the built-upon environment should be planned, designed, and constructed to preserve the natural hydrologic qualities inherent to the pristine site — what makes a developed site capable of being called LID is more difficult to define in the context of achieving the requirements of any particular stormwater management ordinance. Is a project worthy of being labeled "Low Impact Development" Has the designer done enough throughout the development planning, design and construction process to meet the intent of LID philosophy? While conventional and LID stormwater management examples on either extreme of the spectrum may be clear cut, the majority of projects incorporate a hybrid approach, combining conventional stormwater management practices with any number of LID techniques. With an infinite number of site specific variables involved, a standard evaluation method is necessary to objectively compare two sites with different natural and proposed characteristics. In the paper to follow, examples from coastal North Carolina permitting programs will be used to construct an example permitting system for sustainable stormwater management plan review. Because of a desire to highlight permitting programs, this paper uses new development permitting as its foundation, but the principles and concepts discussed could be used to objectively evaluate all kinds of stormwater infrastructure improvement projects. The permitting system proposed in this paper draws from real world examples, but is not an actual permitting program at this time.