Consider incorporating CO2 sensors or outdoor airflow monitors into the building design, as required by the credit. Discuss with the project team the indoor air quality (IAQ) and energy benefits of installing monitoring devices in the project.
Determine the best ventilation strategy for your building: natural, mechanical, or mixed-mode ventilation. The choice of ventilation system is more likely to be shaped by the LEED minimum ventilation prerequisite (IEQp1) and increased ventilation credit (IEQc2), not this credit.
Integrating the stormwater plan into the design at an early stage and calculating the stormwater reduction percentages significantly decreases additional costs. This way, landscaping and building infrastructure can be designed with stormwater reduction in mind.
Quantity of stormwater is typically the more difficult measurement for project teams to reduce. Detention basins can help reduce peak flow rate, but they may not reduce overall stormwater quantity. This is a common municipal requirement, and you may need to take additional measures to meet the credit requirements.
Some jurisdictions may have stormwater standards that are similar to the LEED requirements. For example, Portland, Oregon's Title 17, Public Improvements, Chapter 17, 17.38.030 Section C, states that the quantity and flow rate of stormwater leaving the site after development shall be equal to or less than the quantity and flow rate of stormwater leaving the site before development, as much as is practicable.
Research historical climate records to understand the frequency, intensity, and duration of the design storm event. A longer record of daily rainfall events (rather than monthly rainfall averages) will result in more accurate sizing of components like cisterns.
We recommend that the civil engineer conduct a cost-benefit analysis of stormwater-reduction strategies, including cisterns, porous pavement, rain gardens, parking garages (instead of parking lots), detention ponds, green roofs, sand filters, or detention tanks.
The Rational Method is the most common for determining peak discharge rate and runoff volume. It requires the runoff coefficient for each surface type, the total area for each surface type, and the total project area.
