Timeline of Key Milestones and Dates

Timeline of Key Milestones and DatesDate Key Milestone

February 2007 Washtenaw County Drain Commissioner’s Office authorizes a project to identify opportunities to reduce flooding and improve water quality in Allen Creek

Summer 2007 After evaluating potential projects - and 5 public hearings - Pioneer High School identified as the #1 opportunity in the watershed for storm water improvements

October 10, 2007 Presented project concept to the Board of Education, obtained support to pursue grant and loan funding

July 1, 2008 DEQ loan application submitted to Michigan Department of Environmental Quality requesting 4.4 million dollars for Pioneer High School storm water project

August 20, 2008 Project update presented at Board of Education meeting. The Board passed a resolution supporting the project as developed with AAPS and authorizing the superintendent to provide the necessary easements

Date Key MilestoneOctober 2008 Notification from the Michigan Department of

Environmental Quality that the storm water project is funded for 4.4 million dollars

October 2008 Design project authorized by Washtenaw County Drain Commissioner’s Office

November 2008 Pioneer High School storm water project options developed for Ann Arbor Public Schools’ consideration

December 3, 2008

Presentation to Ann Arbor Public Schools board members of storm water project options

January 20, 2009 Prepare draft plans and specifications in partnership with AAPS for MDEQ review

March 27, 2009 Working with AAPS continue to revise plans for final approval by MDEQ by

June-August 2009 and 2010

Construction

June 22, 2009 Loan closing

OPTION 1

OPTION 2

COMPARISON OF SITE LAYOUT OPTIONSDESIGN ASPECTS OPTION 1 OPTION 2

Basin Locations Two basins in grass area

Grass and parking lot

Infiltration CapabilitiesYes for westerly basin /* unknown for easterly basin

Yes in the grass area / No under the parking lot

Water Quality/Stormwater Benefit E. coli Phosphorous Volume Rate Credit

115-308 acres93 lbs $3,836 per lb321,000 $13.70 cfMin 12% $1,440

115 acres maximum63 lbs; $5,702 per lb225,000 $19.60 cfMin 6% $720

Volume-For basin off 42” sewer -For basin off 54” sewer

125,000 cft196,000 cft

125,000 cft100,000 cft

Approximate BasinDimensions-For basin off 42” sewer-For basin off 54” sewer

156’ x 100’ x 8’220’ x 150’ x 6’

156’ x 100’ x 8’155’ x 110’ x 6’

Hydraulic Grades-For basin off 42” sewer -For basin off 54” sewer

9” increase in water surface at str. # 16

6” increase in water surface at str. # 15

9” increase in water surface at str. # 16

33” increase in water surface at str. #15 (may impact pool discharge)

Facets of Construction

> No impact to soccer field> Some possible impacts to parking lots; contractor may have to use a portion of lot for staging> Northerly entrance drive off of would need to be shared with school traffic or closed to school traffic if basins built consecutively> Native materials can be used for backfill> Schedule would be more flexible starting after football season and continuing into the school year> More soil to level out playfield area/football parking area

> No impact to soccer field> Most of parking lot must be removed and replaced; therefore, work would have to be done in a summer season> Some fill would need to be imported to backfill area under parking lot> Parking lot lighting must be removed and replaced> Both entrance drives off of Main St. would need to be utilized for construction traffic> Less soil to level out playfield area/football parking area