Climate and Stormwater

Stormwater practitioners are now taking a more holistic approach to watershed planning, stormwater design, and infrastructure maintenance to better account for the impacts of climate change. By utilizing better data, considering project lifespans, and properly valuing the co-benefits of nature-based solutions, communities are planning for more resilient futures. 

Stormwater practitioners use precipitation data derived from a combination of federal datasets and design standards. The most widely used dataset is NOAA Atlas 14, which provides 24-hour, 6-hour, 1-hour, etc., rainfall totals for various return intervals (e.g., 2-year, 10-year, 100-year storms).

These datasets provide analysis of historic precipitation data to inform the sizing of critical stormwater infrastructure. However, historic data is no longer representative of current and future conditions. Today’s stormwater managers are preparing for greater precipitation intensity, warmer temperatures, and rising sea levels in the Chesapeake Bay watershed compared to the past several decades

As a result, many states and municipalities are incorporating their own data into their modeling to account for gaps in Atlas 14, using locally observed rainfall records to update their design standards for stormwater practices. NOAA Atlas 15 is in development, and will incorporate climate-adjusted precipitation frequency.