Green Infrastructure Solutions – NVOC’s Porous Pavement Performance Study

Sylvan Avenue –  Ann Arbor, Michigan: The City of Ann Arbor is currently installing one of the first permeable pavement streets in southeast Michigan.  Permeable pavement, due to its porous nature, allows a significant amount of storm water to be absorbed back into the ground, rather than adding to a city’s storm water system.  In combined sewer communities porous pavement saves money and energy that would normally be required to treat and/or pump storm water.  In communities where sewers are separated it, reduces polluted flow volumes from entering our waterways.   In addition, porous pavement also greatly reduces flooding.  However, much of what is known about the performance of porous pavement is theoretical and experimental.  Looking for trends and comparisons to better understand the changes in storm water volumes due to porous pavement, the city of Ann Arbor recently accepted a proposal from NVOC to evaluate storm water discharge before and after construction. .

To collect the data needed, NVOC installed a v-notch weir and two pressure transducers into the manhole directly in front of Sylvan Avenue’s storm water collection pipe (see photo).  Utilizing this data in combination with the weir plate and a rainfall data, comparisons can be formulated between rainfall event size and approximate discharge of water into Sylvan Avenue’s storm sewer.

NVOC began preconstruction flow monitoring on Sylvan Avenue in late April, obtaining data for several significant rainfall events.  Removal of existing pavement began in late May with an anticipated completion of the porous pavement by mid July of this year.  The monitoring will continue for roughly 18 months.  NVOC will present data to the city at 6 month intervals.   This performance data will assist

NVOC in quantifying the actual volume reductions achievable through the installation of porous pavement and further our water/energy nexus work.