Curb Cut Raingardens

IMG_2015

During the summer of 2014, two rain garden bio-retention basins were installed on properties located at 507 and 508 Panther Trail.  These basins were installed as a pilot project with portions of funding from the Yahara WINs Reverse Auction Pilot program and Dane County's Urban Stormwater Pollution Prevention program.    

Construction began on August 12, 2014.  The basin at 507 Panther Trail is 8’ x 12’ x 4’.  The basin at 508 Panther Trail is 8’ x 12’-6” x 3’.  The depth of the basin at 508 Panther was limited by a gas line adjacent to the basin.  Construction of the basins occurred during the course of one day.  Final site stabilization occurred within the week and plantings occurred shortly thereafter. 

A modeling effort was conducted for the two bio-retention basins constructed based on their as-built conditions.  Using the as-built conditions, the estimated Total Phosphorous removed per year is 5.40 pounds for both basins. Modeling of the reduction for the basins, as constructed, showed a 49% reduction in Total Phosphorous.

 

Total Phosphorous (TP)

Total 15-yr Service Life TP Reduction (lbs)

Construction Cost

Cost per Pounds of TP Removed

 

Without Basin

(lbs/yr.)

With Basin

(lbs/yr)

Reduction

(lbs/yr)

507 Panther

0.40

0.23

0.17

2.55

 

 

508 Panther

0.34

0.154

0.19

2.85

 

 

Totals

0.74

0.38

0.36

5.40

$8,303.25

$1536.79

The initial SLAMM modeling effort estimated the cost for Total Phosphorous removed would be $1,000 per pound.  The updated modeling in June 2014 showed a potential cost per pound of Total Phosphorous removed to be $1823.18. The actual cost per pound of Phosphorous removed, based on the as-built conditions, is estimated to be $1536.79 per pound. 




Excavation and Installation of Under Drain

508 Panther 8.12.14_2

Coconut mat installed

508 Panther 8.18.14_1

Back fill

507 Panther 8.12.14.2

Pre-planting

508 Panther 8.18.14_2

Pre-planting

507 Panther 8.18.14.2

Post Construction Planting

508 Panther 9.3.14

Year 2 Growing Season

IMG_2016