Landscape Architects Need Better Data to Design for the Future
planitimpact / May 31, 2019
There is no doubt that cities across the United States are facing the consequences of aging stormwater infrastructure. As billions of dollars are spent managing stormwater, cites such as Kansas City and Philadelphia are taking a green infrastructure approach to address future needs and meet regulatory demands from the EPA.
In both of these cases, the cities’ current stormwater management needs outweigh the capacity of existing gray infrastructure. One of the driving reasons for this is not only age, but increase in rainfall throughout the United States. This is exemplified in the Mid-America Regional Council’s Green Infrastructure Framework for the Kansas City metro area:
“Measured data over the past half century has shown an increase of four inches of average annual rainfall. It is predicted that rainfall will continue to increase through the last half of this century by as much as six inches of average annual rainfall.”
The resulting challenge for landscape architects is how to accommodate the growing need for green infrastructure elements grounded in future conditions. Some firms are working with cities to develop typologies and toolkits to achieve water management goals. But if we look to existing design resources such as public agencies (to which certification systems like SITES point), their historically-derived data for stormwater design calculations isn’t as applicable to future trends as they once were.
Sometimes these resources lock designers into arbitrary or outdated values for capturing rainfall. The issue is not with the methodology of these sources, but rather with the “moving average” of climate data, even over 30-year periods. There’s no time or budget to continuously update the depth of design rainfall events even as these values have changed in the last 10 years. SITES partially tackles this by defining statistical events as targets rather than specific depths. But for designers to evaluate historical data themselves is difficult, time-consuming, and sometimes unclear how or when data can be used. This also makes it expensive for clients.
PlanIT Impact’s upcoming stormwater module will leverage better data by utilizing the Unity API. By relying on algorithms that compute more specific location-based observational data, we can automatically use more recent, spatially-detailed rainfall data to calculate design conditions relevant at the site scale. PlanIT Impact provides an easy-to-use survey of climate data and plugs it into standard models. It quickly turns troves of data into legible information for designers and their clients.
This is only the beginning. As landscape architects look forward to the end of the 21st century, it will be necessary to future-cast designs to see how they hold up to future conditions, rather than rely on historical data that no longer reflects the world as we know it today.