Portland Community College
OP-23: Rainwater Management

FMS has championed its stormwater program in collaboration with Clean Water Services and the Portland Bureau of Environmental Services. For example, the CLIMB Storm Water Education Plaza project was selected as one of the “2013 Top Storm Water and Erosion Control Projects” in the U.S. by Storm Water Solutions. Grounds, with the help of the Bond, has installed and maintained many new bio-swales throughout the district to slow down, filter and infiltrate storm water runoff naturally. The use of permeable pavers in our standards has also helped reduce runoff from our PCC FMS Sustainability 5 August, 2015 parking lots and Grounds installs buffer zones of plant material to prevent erosion and sediment from getting into the ponds and waterways around the campuses that have them. Additionally, Grounds has a storm water injection management program (SWIMP) with strict guidelines for maintaining PCC storm water facilities. These landscape and physical features improve water quality on campus, in natural waterways and communities downstream. PCC uses techniques to handle stormwater such as engineered drains with filters, dry wells and vegetated swales to mitigate stormwater runoff. Dry wells are currently being used at the Metro, Cascade and SE Center campuses. Rock Creek is also in the process of major storm water mitigation enhancements with Bond funding. The Sylvania campus covers 122 acres, 57% of which are pervious (allowing for infiltration into the soil), and 43% of which are impervious (does not infiltrate). The campus is located on the lower slope of Mt. Sylvania, an old volcanic vent, and forms the headwaters of Fanno Creek. Much of the campus was previously covered with a mixed-conifer forest. Soils are poorly drained due to high clay content and fractured basalt rock near the surface. Annual rainfall at the campus totals 122 Million Gallons per Year (MGY). Of that total, 80% is considered runoff from buildings or other impervious surfaces, 10% is infiltrated and 10% is subject to evapotranspiration. The existing stormwater management system consists of three primary drainage areas. “Area A” drains stormwater mostly from the east and southeast parking areas and discharges to an surface outfall located along the loop road near the campus services building. “Area B” drains building rooftops and two small parking areas along the southwest portion of the campus, and discharges to a surface outfall just to the west of the Area A outfall. Stormwater from Areas A and B contributes to existing stream channels to the south of the campus. “Area C” drains all the north, northeast and northwest parking lots. Area C stormwater is discharged to an existing stream channel near the northwest entrance at Lesser Road. Runoff volumes from impervious areas total 44.2 MGY, with 48% of the total from parking 15 Gerding Edlen Sustainable Solutions THE E6 NET ZERO PROJECT: PCC areas, 39% from streets and the remainder from building rooftops. Stormwater rates are assessed from both on-site (private) and off-site (public) charges, the latter comprising the majority of the fee. “Private” charges are those related to stormwater that is generated on site and sent off-site for treatment; “public” stormwater charges are assessed by the city to all residents and businesses in its jurisdiction to cover system fees. As the assessment is not a function of stormwater volumes generated, it can not be reduced or avoided.

Campus-wide water strategies include reductions in building water consumption, irrigation use, and sanitary sewer wastewater volumes. Stormwater management strategies that would dramatically reduce site runoff and ensure that 100% of site stormwater is treated were also emphasized. Finally, all campus stormwater generated from impervious areas needs to be managed in some fashion –infiltrated, detained, reused, or treated. Infiltration is usually the primary goal, but here treatment of runoff is critical since the low infiltration rates of the soil helps the campus function as the headwaters for Fanno Creek.