This is one of two stormwater retention ponds or beds found on the north side of the property that will be used to treat and control stormwater runoff from the paved driveways and parking areas. Here the site contractor is excavating the retention pond--also referred to as a Stormwater BMP—which will eventually be partially backfilled with a soil mixture containing vegetation or biological matter than acts as a filtration system to remove pollutants that accumulate in the runoff.
Here the BMP now completely excavated, will also contain several types of local indigenous plants in addition to the special soil mixture, that also aid in the stabilization and filtration of the stormwater runoff. The concrete pipe seen in the background is for overflow during extreme downpours or severe weather. When the BMP becomes full; the water then flows into the overflow pipe and is carried underground to another drainage basin at the western edge of the property.
When it rains the stormwater drains off the paved driveways and parking areas into the retention pond where it is collected and treated. Stormwater can collect many pollutants as it passes over the surface of the paved areas, such as fuel, oil, heavy metals, and other contaminants that accumulate from regular vehicle traffic.
Viewed from the building, here is the same BMP after one of our heavy rainfalls this year.
This is the second BMP which is located on the south side of the property along Fiddler Green Road. It will follow the same process as the other retention pond, but will collect the stormwater runoff from the front side of the property. When completed, it will also contain the special soil mixture with plants for filtration, treatment, and stabilization. The soil mixture and plants will breakdown and filter the pollutants from the paved areas preventing them from entering back into the ground water and polluting the natural water ecology of the surrounding area.
Instead of an overflow pipe, the south side BMP seen here has a landscaped ditch that will carry overflow stormwater to the drainage basin on the west side of the property. All stormwater is captured, stabilized, and treated on site before it is released back into the ground water or surrounding stream system off site.
Here is the same BMP along Fiddler Green Road just a few weeks later after some heavy rainfall. Although none of the special soil mixture or plants has been added to the retention pond, it is already doing the job of collecting the stormwater runoff. At this point in the construction process it is acting more as a sediment control trap than stormwater filtration.
In addition to both BMPs (retention ponds) shown previously, this is the third stormwater management component commonly referred to as filterra boxes or filterra bioretention units. These units collect stormwater on the west side of the property to also filter and treat the runoff and to help stabilize it and control its direction. In the bottom left corner of this picture is the outflow end of the overflow pipe from the north side BMP. Both filterra boxes and the overflow pipe dispense and direct stormwater runoff into the drainage basin on the west side of the property so that it is properly controlled and managed.
In addition to the development of the BMPs, the entire site must be covered with a layer of gravel, commonly referred to as “crush & run”. This will prepare the paved areas for curbing and pavement. Once the base subgrade has been built up with good fill material, a final layer of gravel is laid as the final subgrade preparation for pavement. The entire site must also pass compaction testing through proof rolling to ensure the ground can support the pavement that will carry the heavy vehicle and bus traffic.
After the crush and run has been placed the concrete subcontractor lays out the curbing for the drive lanes and parking areas. This may also include a gutter pan in certain areas. This picture shows the outside edge of what will be the employee parking lot in front of the building.
Here the concrete crew lays out the curb edge with a gutter pan on the entrance way and drive lane onto the property. The curb machine is an amazing piece of machinery that takes raw, wet concrete and dispenses it in a finished form for curbing and gutter that requires only minimal touch ups from the crew.
In addition to the curb and gutter pan, the concrete crew lays out a sidewalk that will run along the entire roadway frontage of the property beside Fiddler Green Road. This was required by Gloucester County to meet the local Planning Department’s directives of creating inter-connectivity and walkways for pedestrians. Notice the drainage ditch on the left side of the sidewalk which will feed storm-water runoff to the south side BMP, mentioned previously, for treatment.
Here the concrete crew hand forms and pours the sidewalk along Fiddler Green Road.
Many machines and powered tools are used by all the construction trades to make their work more efficient and less labor intensive. Here is a modern, powered version of what used to be called a “wheelbarrow”. It is now called a “concrete power buggy” and can carry more than several wheelbarrow loads at once with only a fraction of the physical effort. The operator of this equipment is standing on a platform attached to the rear of the buggy that allows him to ride along as he steers the load. It’s almost like cheating!