Old Town Alexandria Sustainable Landscape Design & Installation

Introduction

 The purpose of this work is to outline a six-phase, multidisciplinary project completed December 2019- January 2020 on the 300 block of N. West St. in Alexandria, Virginia. These six phases are listed below in order of their completion. The first three phases of the project focus on the installation of sustainable hardscaping, the fourth and fifth phases focus on the installation of stormwater management infrastructure, and the sixth phase is a proposed native rain garden and BayScape design with speculative installation scope. All phases of the project seek to maintain and exemplify the highest industry standards possible with extra emphasis on sustainability standards as set by Chesapeake Bay Landscape Professionals (CBLP). 

1. Area Prep Work (12/27/2020)

To begin the project, we first installed two railroad tie planters that are each approximately 20′ x 2′ x 2′. We excavated and removed soil, then installed layers of small stone to provide a level foundation, referred to as an “aggregate base”. Once the foundation was secured, we then installed a PVC liner to prevent the leaching of any noxious chemicals into the soil. Railroad ties were anchored and secured using rebar. We then installed 2 x 8 wooden planks along the top of the planters to create additional seating while maintaining the present style motif. ESTIMATED MATERIAL COST

• • Railroad Ties= $1,200.00 
  • Topsoil=  $500.00
  • Lumber= $250.00
  • Aggregate= $150.00
  • Rebar= $100.00
  • PVC Liner=: $200.00
• TOTAL ESTIMATED MATERIAL COST: $2,400.00

ESTIMATED LABOR COST

• • Project Manager Hours: 8 @ $95.00/hour= $760.00
  • Specialist Hours: 8 @ $75.00/hour=- $600.00
  • Technician Hours: 24 @ $55.00= $1320.00
• TOTAL ESTIMATED LABOR COST: $2,680.00

TOTAL ESTIMATED PROJECT COST: $5,080.00 

2. Permeable Brick Paver Walkway (12/30/2019)

We began by sourcing historic brick from our collection of recycled building materials to use in the project. Before these bricks could be laid, we had to first spread a layer of fine stone dust to help with the compaction. Once this was complete and the bricks secured, we finished by sweeping fine stone dust into the joints between the bricks. ESTIMATED EQUIPMENT COST

• • Excavator 1-Week Rental= $1,600.00
  • Front Loader= $500.00
  • Specialty Dump Truck <8’ wide= $500.00
• TOTAL ESTIMATED EQUIPMENT COST: $2,600.00

ESTIMATED MATERIAL COST

• • Stone materials= $1,252.78
  • Geotextile and anchors= $300.00
  • Disposal fee= $1200.00
• TOTAL ESTIMATED MATERIAL COST: $2,752.78

ESTIMATED LABOR COST

• • Project Manager Hours: 16 @ $95.00/hour= $1,520.00
  • Specialist Hours: 24 @ $75.00/hour= $1,800.00
  • Technician Hours: 64 @ $55.00/hour= $3,520.00
• TOTAL ESTIMATED LABOR COST: $6,840.00

TOTAL ESTIMATED PROJECT COST: $12,192.78

3. Hardscape Installation (01/14/2020)

After the site was prepared, we installed a 22′ x 10′ hardscape driveway. This first required excavating and removing large amounts of soil and then installing three layers of different sized stones to create an extra-secure aggregate base. The first one laid is called #2 stone, followed by a #57 stone, and a #8 stone. Once these layers were secured, the perimeter of the patio area was formed using a 6’ x 6″ area of crushed stone to serve as a bedding layer for brick edging. Soon after, the client had selected his preferred style of pavers for the project and they were promptly installed. The spaces between the pavers were then measured to confirm they were large enough to allow the steady flow of rainwater, and finally filled with stones to create a more full, connected style.    ESTIMATED MATERIAL COST

• • Historic brick= $800.00
  • Geotextile= $100.00
  • Stone dust= $150.00
  • Edging restraint= $60.00
• TOTAL ESTIMATED MATERIAL COST: $1,110.00

ESTIMATED LABOR COST

• • Project Manager Hours: 6 @ $95.00/hour= $570.00
  • Specialist Hours: 8 @ $75.00/hour= $600.00
  • Technician Hours: 8 @ $55.00/hour= $440.00
• TOTAL ESTIMATED LABOR COST: $1,610.00

TOTAL ESTIMATED PROJECT COST: $2,720.00

4. Rain Garden Installation (05/06/2020)

Before starting the project, we were given five specifications by the client:

1. The lowest point of the backyard must be in the center of the rain garden to ensure water pools there.
2. The four corners of the rain garden must be:
   1. Lower than the surrounding hardscape
   2. All the same height
3. Existing bricks near the backdoor must not be adjusted.
4. Existing bricks between the edges of the lot and the rain garden must be adjusted so that water flows into the rain garden.
5. Existing bricks near the patio must not be adjusted.

To begin the installation, we first had to excavate some existing soil in the planter bed. The remaining heavy-clay soil was then mixed with sand, mulch, and compost using a rototiller machine to increase the amount of water and nutrients that could flow through it. Then, as per the client’s specifications, the brick pavers lining the planter had to be readjusted to ensure their pitch angle would allow water to flow into the rain garden. Once the hardscape had been secured, the client provided us with a personally-curated collection of grasses and sedges for planting. The holes for these plants were dug and then filled with compost to increase the soil’s fertility. Lastly, the plants were placed in their locations and watered in.   ESTIMATED MATERIAL AND LABOR COST

• • 1 ton of sand
  • 1 ton of compost
  • 1 ton of No. 8 stone
  • 1 full-team day

• TOTAL ESTIMATED PROJECT COST: $3,270.00

5. Install Shed Gutter, Underground Drainage Lines, and Two Underground Dry-wells (05/06/2020)

After installing the gutter to the existing shed, we excavated a large amount of soil and installed the connected drainage lines and dry-wells underground. These dry-wells create extra stormwater retention space for the garden while also protecting the surrounding hardscape from excessive runoff that erodes it over time, (a link to their schematics is available below.)  The dry-wells were equipped with pop-up valves that allow excess water to flow into the location of the planned rain garden.  Flo-Well-Assembly-and-Installation-I ESTIMATED MATERIAL COST

• • ~50′ of Drainage Pipe= $100.00 
  • Fitting and connectors of gutters and downspouts= $60.00 
  • Allowance for drainage adapters= $100.00 
  • Downspout filter= $20.00 
  • 2 X NDS Flo-Well and adapters= $3,000.00 
  • 1 ton of No. 57 stone= $75.00 
  • Geotextile= $75.00 
  • Hauling and disposal of excavated soil: $175.00

• TOTAL ESTIMATED MATERIAL COST: $3,605.00

ESTIMATED LABOR COST

• • Project Manager Hours: 8 @ $95.00/hour= $760.00
  • Specialist Hours: 20 @ $75.00/hour= $1,500.00
  • Technician Hours: 30 @ $55.00/hour= $1,650.00

• TOTAL ESTIMATED LABOR COST: $3,910.00

TOTAL ESTIMATED PROJECT COST: $7,515.00

6. BayScape/Rain Garden Plant Installation Proposal 

The purpose of this project is to optimize the space and functionality of the previously installed rain garden through an emphasis on regional natives and their respective staging in the garden, as per CBLP standards. It should be noted, though this installation has not occurred, we are ready and willing to complete it– attractive, native-dense landscapes with utilitarian purpose in their plant selection exemplify the highest industry standards of design and sustainability we seek to maintain on all our projects. The scope outlined below covers the installation of both a rain garden and a BayScape, defined as a landscape with an emphasis on natives to the Chesapeake Bay region. The rain garden has an emphasis on plants able to survive through fluctuating water levels while the BayScape, encompassing the rest of the lot, has an emphasis on native woodland and fruit-bearing plants, as a nod to the theme of previous designs that featured non-native apples, berries, and other fruits. A PDF copy of this design is available for review by clicking the link below. Drudi Proposed Landscape Design We will begin the project by contacting Miss Utility to confirm the locations of nearby utility lines. Once utility lines are noted and marked, we will hand-dig 119 planting holes in predetermined locations. These planting holes will be amended with soil conditioner and compost/manure. Plants will then be removed from their containers, inspected, and then have their root balls expressed to ensure root establishment. Once they are ready, we will place plants in respective, predetermined locations and then back-fill their planting holes with soil conditioner and compost/manure to an approximate ratio of 1:1. Once back-filled, plants will be watered to an adequate moisture level to ensure root establishment. We will top all planting areas with a 2” cover of brown hardwood mulch to regulate moisture, temperature, and gas exchange. Once the mulch is laid, we will haul and dispose of any debris left from the project.  ESTIMATED MATERIAL COST

• • 2 X #5 Amelanchier arborea @ $50.00 a piece = $100.00
  • 3 X #3 Lobelia cardinalis @ $10.00 a piece= $30.00
  • 20 X #1 Asarum canadense @ $8.00 a piece= $160.00
  • 4 X #3 Vaccinium virgatum @ $36.00 a piece= $144.00
  • 20 X #1 Heuchera americana @ $10.00 a piece= $200.00
  • 20 X #1 Itea virginica @ $20.00 a piece= $400.00
  • 20 X #1 Carex stricta @ $10.00 a piece= $200.0
  • 10 X #1 Symphyotrichum novae-angliae @ $10.00 a piece= $100.00
  • 4 X #3 Cornus sericea @ $35.00 a piece= $140.00
  • 9 X #1 Adiantum sp. @ $10.00 a piece= $90.00 
  • 2 X #3 Hydrangea quercifolia @ $50.00 a piece= $100.00
  • 1 X #5 Asima triolba @ $120.00 a piece= $120.00
  • 25 X 3 cu. ft. bags of brown hardwood mulch @ $12.00 a piece= $300.00
  • 30 X 3 cu ft. bags of compost/manure @ $12.00 a piece= $360.00
  • 30 X 2 cu. ft. bags of soil conditioner @ $10.00 a piece= $300.00
  • 1 X Hauling and disposal fee @ $150.00= $150.00
• TOTAL ESTIMATED MATERIAL COST: $2,894.00

ESTIMATED LABOR COST

• • Project Manager: 3 hours @ $105.00/hour= $315.00
  • Specialist: 15 hours @ $85.00/hour= $1,275.00
  • Technician: 15 hours @ $65.00/hour= $975.00
• TOTAL ESTIMATED LABOR COST: $2,565.00

TOTAL ESTIMATED PROJECT COST: $5,459.00

OVERALL ESTIMATED COST OF PROJECTS: $36,236.78

7. Access Gate and Other Details

Summary and Findings

The scope of this six-phase project is one of the largest and most comprehensive our company has embarked upon to date. Throughout the course of work, we impacted multiple aspects of the existing greenspace; we made improvements to the current hardscape through the addition of 220 sq. feet of permeable pavers that will result in an estimated 3,837.68 gallons of rainwater permeating more 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 replaced the unsustainable yard area with 54 sq. feet of mulch bedding that will result in the sustainable permeation of 1,345.68 gallons of rainwater 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”.) We increased the stormwater management potential of the property through the addition of three pieces of infrastructure that offer 150 gallons of retention area. We installed 52 plants in the space along with a proposed design that would install another 119 native plants to the rain garden and BayScape. Through our multidisciplinary efforts, this property has significantly increased sustainability potential in its hardscape, softscape, and stormwater management with proposed plans for further improvement.