Alternative Computational Approach Improving Hydrologic Design of Low‐Impact Development Facilities

ABSTRACT Low‐impact development (LID) facilities such as bioretention cells, infiltration trenches, permeable pavements, rainwater harvesting systems, and green roofs are widely used in North America to reduce the detrimental environmental impact of urban development. The design‐storm approach is commonly used for determining the required sizes of LID facilities. An alternative computational approach was recently developed that uses analytical equations to directly quantify LID facilities' hydrologic performance statistics. These equations enable the convenient sizing of individual LID facilities to achieve desired levels of performance. The main objectives of this commentary are (1) to illustrate how this approach was developed, (2) to demonstrate how this new approach may be used in engineering practice, and (3) to reveal the shortcomings of the conventional approach and demonstrate how the new approach may be used to improve the hydrologic design of LID facilities. Also described in this commentary are the obstacles that may be encountered in the adaptation and implementation of the new approach and what may be done to remove them.