Tracking Installed Stormwater Infiltration

Why This Target?

Installed Stormwater Infiltration is a measure of the estimated amount of rainfall that is captured and infiltrated by the Green Infrastructure that the City of Ann Arbor and residents have built to manage stormwater.  The natural landscape and environment provide additional infiltration that is not included in this estimation.​

​The Data​​​​

Interpreting the Results

Infiltration estimate should continue to increase over time as the city constructs and maintains more green infrastructure to manage stormwater across the City.  The City of Ann Arbor is on the progressive edge of stormwater management using methods that mimic nature wherever possible. There is currently no industry benchmark or standard to compare results.

The fine print

Please note only residential rain gardens receiving a stormwater billing credit are included in this approximation. For this estimate we assume that the typical residential rain garden is 130 sq. ft. and infiltrates 10,946 gallons of stormwater in a typical year.  There are limitations on the interpretation of this data as the estimation is based on assumptions about infiltration rates and antecedent soil moisture conditions. ​​

To learn more about rain gardens, rain barrels, and other ways residents can earn stormwater billing credits while helping the environment, visit the city's page on Residential Stormwater Credits.