During a storm, rainwater can have a vastly different impact depending on where it lands. This can be the difference between runoff going through a backyard into the woods or picking up nutrients on a chicken farm before going into the Chesapeake Bay.

(Photo of Johnson-Whittle and Pyon-Chen Residence Halls https://ayerssaintgross.com/work/project/university-of-maryland-college-park-residence-halls/ )

Rain gardens are a solution to mitigate a home’s runoff. Rain gardens are shallow depressions made up of well draining soil and plants that can handle both wet and dry conditions. These depressions are meant to take in several inches of water and drain that water in less than two days.

Larger commercial areas or farmland will produce way more water than a simple rain garden could handle. This requires more complex systems commonly referred to as bioretention cells. These cells are deeply set in the ground and can have both engineered soil and a drainage pipe with a gravel layer underneath. These allow for large amounts of water flow and fast, filtering drainage times. These systems also have safety features like specific overflow sections and designs that promote plant health. Overall maximizing both runoff and nutrients collected.

Bioretention cells are actually a spectrum. The simplest form typically holds the name of a rain garden. This means each cell can be personally designed for the plot of land, depending on both nutrient and runoff demand.

Read more at:
https://extension.umd.edu/sites/extension.umd.edu/files/2021-03/FC-MGPub%20Rain%20Gardens%20Rainscaping.pdf
https://megamanual.geosyntec.com/npsmanual/bioretentionareasandraingardens.aspx