Old Town Alexandria Turf, Hardscape, and Stormwater Infrastructure Improvements

Introduction

The purpose of this work is to outline the scope of a multidisciplinary project completed May-June 2020 in Alexandria, Virginia. The project provided substantial improvements to the sustainability of the property by installing permeable hardscape, synthetic turf, and by extending stormwater management infrastructure. All parts of the project seek to maintain and exemplify the highest industry standards possible with extra emphasis on sustainability standards as set by the Interlocking Concrete Paving Institute (ICPI) and Chesapeake Bay Landscape Professionals (CBLP). 

Consultation (05/11/2020)

Our team was contacted by the clients to provide consultation on the installation of artificial turf for an area behind their home, next to a parking pad. Upon meeting with the clients, they emphasized the importance of using the hardscape and turf installation to create an attractive, inviting space to facilitate outdoor entertaining. Through further conversation, we educated the owners on the importance of permeability in turf and building a more sustainable property. Excited about the potential of a more environmentally-friendly home, the clients were eager to select options that were both aesthetically pleasing and permeable. 

 

Plant Transplant (05/29/2020)

Before excavation started, we salvaged plants from the existing garden to be reintroduced after the project including; three oakleaf hydrangeas (Hydrangea quercifolia), five cherry laurels (Prunus laurocerasus), and twelve heucheras (Heuchera americana). Between the hydrangeas and the heucheras, we salvaged fifteen native plants. Once the project scope had been completed, we reinstalled the three oakleaf hydrangeas in planters constructed from recycled wine barrels for a rustic, established appearance. The team transported the remaining plants to a location where they could be transplanted and kept to be repurposed on future planting projects. 

 

Excavation  (05/29/2020)

In order to ensure level height with the existing walkways and that water would drain properly through the area, we resolved to excavate 300 square feet of soil at roughly eight inches depth. Miss Utility was contacted and they indicated the presence of a few utility lines in the area; therefore, abiding by OSHA safety regulations, the project was to proceed using only hand tools.

ESTIMATED LABOR COSTS:
Project Manager Hours: 2 @ $105/hour= $210.00
Foreman Hours: 12 @ $85/hour= $1,020.00
Technician Hours: 12 @ $65/hour= $780.00

TOTAL ESTIMATED COSTS: $2,010.00

 

Stormwater Management Infrastructure Installation (06/01/2020)

Once excavation began and the existing drainage system, which was installed as part of a pre-existing permeable paver car pad, could be examined our team realized the potential for improvements.  After discussing the importance of stormwater management with the clients, we decided to install an exfiltration/underdrain system that would improve the home’s resilience against flood damage during extremely heavy rain events. After excavating more soil and excavating a channel below the concrete sidewalk, we installed strips of 4′ non-woven geotextile to provide a substrate barrier between the subbase and base. This addition extends the life of the installation and also makes the area more resilient against damage from tree roots. TLC then installed a perforated PVC pipe connected via a tee fitting onto the existing drainage line. When precipitation rates exceed absorption rates on the property, these additions serve to alleviate stormwater flooding by providing more space through which water can overflow sustainably. 

ESTIMATED MATERIAL COSTS:
PVC Pipe, Fittings, Speciality 5-6” fitting: $150 X 2= $300.00

ESTIMATED LABOR COSTS:
Specialist Hours: 6 @ $85/hour= $510.00

TOTAL ESTIMATED COSTS: $810.00

 

 

Subbase Prep (06/02/2020)

Our team spread roughly four inches of open-grade No. 57 stone to start forming our aggregate base. We utilized a ZipLevel tool to ensure a grade that would allow water to flow away from the foundation of the home a well as to ensure that the grade of the various parts of the patio would complement the different levels of the car pad, sidewalk, rear door, and fence line. We then utilized a Wacker Neuson plate compactor to achieve approximately 98% density.

ESTIMATED MATERIAL COSTS:
2.5 tons of No. 57 stone: $200.00
1.5 tons of No. 8 stone: $150.00

TOTAL ESTIMATED MATERIAL COSTS: $350.00

ESTIMATED EQUIPMENT COSTS:
ZipLevel: $50.00
Wacker Neuson Plate Compactor: $75.00

TOTAL ESTIMATED EQUIPMENT COSTS: $125.00

ESTIMATED LABOR COSTS:
Project Manager Hours: 2 @ $105/hour= $210.00
Foreman Hours: 12 @ $85/hour= $1,020.00
Specialist Hours: 12 @ $85/hour= $1,020.00

TOTAL ESTIMATED LABOR COSTS: $2,250.00

TOTAL ESTIMATED COSTS: $2,725.00

 

 

Hardscape & Turfscape Installation (06/06/2020)

TLC then installed a 2” bedding layer of No. 8 stone, following ICPI Permeable Paver Installation best practices. Above this, we installed Techo-Bloc’s Industria Smooth pavers in a beige cream color. (Product specifications are available here.) In order to create the desired appearance and style, these pavers needed to be cut to the correct size and angles using a wet saw. We then installed the pavers in a bordering edge and diagonal grid pattern. For extra strength, metal edging was fitted around the pavers and secured into place using ten-inch steel nails. Once installed, the spaces between the pavers were filled with more No. 8 stone to act as a bedding layer for the turf. In total, the team installed 150 square feet of permeable pavers. For their permeable turf, the clients selected Turf Factory Direct’s TFD N87 Special for its natural feel beneath the feet and its excellent rainfall capacity of 122 inches per hour. (Product specifications are shown below.) Strips of turf were cut to size and secured using ten-inch steel nails. In total, the team installed 300 square feet of artificial turf.

Link to turf product specifications

ESTIMATED MATERIAL COSTS:
Industria Smooth, Beige Cream Pavers: $1,550.00
TFD N87 Special Turf: $645.00
Metal edging: $150.00
Equipment: $50.00
Wet saw: $50.00
TOTAL ESTIMATED MATERIAL COSTS: $2,295.00

ESTIMATED LABOR COSTS:
Project Manager Hours: 2 @ $105/hour= $210.00
Foreman Hours: 8 @ $85/hour= $680.00
Specialist Hours: 8 @ $85/hour= $680.00
TOTAL ESTIMATED LABOR COSTS: $1,570.00

TOTAL ESTIMATED COSTS: $3,865.00

 

 

OVERALL ESTIMATED PROJECT COSTS: $9,410.00

 

SUMMARY AND FINDINGS

This project was a unique one in that it was interactive and educational through its development. What was originally just a beautification project to facilitate outdoor entertainment evolved into sustainability improvements by educating the clients on the importance of permeability in stormwater management.  Throughout the course of work, we impacted multiple aspects of the existing greenspace; we made improvements to the current hardscape through the addition of 150 square feet of permeable pavers that will result in an estimated 2,616.60 gallons of rainwater permeating sustainably in 2021. (Calculated by taking square footage and multiplying it by the product of .623 gallons per inch of rain and Alexandria’s estimated yearly rainfall of 40”, then multiplying that figure by 70% infiltration rate). We installed 300 square feet of permeable turf that will result in an estimated 7,476 gallons of rainwater permeating sustainably in 2021. (Calculated by taking square footage and multiplying it by the product of .623 gallons per inch of rain and Alexandria’s estimated yearly rainfall of 40”). Through our multidisciplinary efforts, this property has significantly increased sustainability potential in its hardscape, turfscape, and stormwater management with great potential for future improvements thanks to friendly, environmentally-conscious clients.