03 May April Rain Puts UpstreamPgh Rain Gardens to the Test
April 2024 was nearly Pittsburgh’s rainiest April on record (falling second to 1901), and it’s been the rainiest start to a year since recording began in 1870. Needless to say, it’s been a true test for the UpstreamPgh rain gardens.
This past month, our Oakwood Batavia and Maple Avenue green stormwater projects, which are equipped with meters to measure their performance, have intercepted an estimated 272,695 gallons of stormwater! That’s over 6,800 bathtubs! In addition to those sites, we have several other green stormwater projects that have helped reduce flooding and kept polluted water out of our rivers this rainy season. These sites are located primarily within the Nine Mile Run Watershed, which includes all of Wilkinsburg and parts of Pittsburgh, Swissvale, and Edgewood. We’ve chosen their locations based on a variety of factors, including land cover, environmental equity scores, and runoff capture potential.
What is a rain garden?
The basic premise of a rain garden is that its concave shape can transform into a small pond during heavy rains, allowing the water to slowly percolate into the soil, roots, and groundwater.
The best time to check on rain gardens is when it’s raining, so we went out during a heavy storm to see what was happening. As you can see in this video, the bioswale in the middle of this Wilkinsburg parking lot is channeling water into a larger rain garden, where the water can pool – reducing flooding in the parking lot and recharging groundwater!
Dornbush St Green Infrastructure Project
The Dornbush St green stormwater project on a sunnier day
We’ve also been closely watching our newest site, the Dornbush St Green Infrastructure Project in East Hills. While the site is yet to be planted, we could see the runoff from Dornbush Street making its way into the two new green-stormwater inlets and into the rain gardens. As you can see in the photo below, stormwater rushing down Dornbush Street (the second steepest street in the city), is channeled through the green-stormwater inlets that connect to the basin.
We also installed a subsurface storage tank, called an R-tank, which captures overflow from the two rain gardens, and then slowly releases it over time. The R-tank system allows the site to manage larger rainfall events than the surface rain gardens can capture. The project is projected to capture up to 1.7 million gallons of runoff per year and we are monitoring the project to verify the projections.
Rain Gardens as Flood Defense
The roughly 18 inches of rain that has drenched Pittsburgh so far this year has caused landslides, property damage, storm-sewer overflows, and road closures from overflowing waterways.
Climate change is causing more intense rain events in the United States, particularly in the Northeast. Like all impacts of the climate crisis, it won’t be felt equally. Flooding compounds issues that low-income communities face, as substandard housing and neglected infrastructure are more vulnerable to flooding damage, and paying for repairs can come at a high cost. Cities like Pittsburgh with aging sewer systems are not equipped to handle these record levels of rainfall, which can result in sewage overflows into our rivers.
Building green stormwater infrastructure is one way we can protect communities from the impacts of climate change. While we need bold policy changes and major investments in renewable energy to address the root causes of the climate crisis, solutions like this can serve as immediate, localized responses to build resilience within our cities.
If you’d like to get more involved in these projects, consider becoming a member of the Environmental Justice Table or volunteering as a rain garden Urban EcoSteward!