IMPLEMENTERS February 2013 Our Islands Our Future GUIDE TO GREEN BUILDING in the USVI Funded by...
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Transcript of IMPLEMENTERS February 2013 Our Islands Our Future GUIDE TO GREEN BUILDING in the USVI Funded by...
IMPLEMENTERS
February 2013
Our IslandsOur Future
GUIDE TO GREEN BUILDING in the USVI
Funded by NOAA’s Coral Reef Conservation Program through NOAA Fisheries Caribbean Field Office
Developed by The FHWGroup and reviewed by a steering committee of federal and VI agencies and NGOs
Guide to Green Building in the VI Introduction
Introduction
2
As a heavy equipment operator or contractor, you play a crucial role in the construction of buildings and the preservation of the environment that surrounds those buildings.
With growing problems of water quality that affect the health of our marine environment, going “green” is a necessity. The information that follows will assist you in preparing sites for your clients in a way that will protect our natural resources and preserve the natural beauty of our islands.
Elevated Double Pedestal House, St. Thomas
Panoramic View of Cruz Bay, St. John
Photo Credit: http://blog.topsider.com/category/home-building-virgin-islands
Guide to Green Building in the VI Introduction
Introduction
3
Your work is your signature and your signature will get you your next job. Your signature will remain on the site forever, so work smart and sign small!
We will show you how to work green before, during, and after site preparation, construction, and final grading and landscaping.
LESSON 1
Work Green Site Preparation
LESSON 2
Work Green Construction
LESSON 3
Work Green Project
Completion
**Click picture to go directly to the lesson of interest
Guide to Green Building in the VI Introduction
Introduction
The lessons contained in this module may be used as a part of an instructor-led course on green design and construction or used directly by construction industry professionals. You can review the lessons in any order based on your interest and expertise.
Development industry professionals completing the full training, including the field component, will be acknowledged publicly and may receive assistance from Island Green Building Association (IGBA).
4
Guide to Green Building in the VI Introduction
Introduction
The lessons that follow will:1. Provide information on
minimizing disturbance to natural resources during site preparation.
2. Provide guidance for installation and maintaining best management practices during construction.
3. Provide guidance for concluding site work, including final grading, landscaping, and maintenance.
5
Photo Credit: ESA Solar – St. John Installation
Rooftop Solar Panel Installation
Intro
Lesson 1
Lesson 2
Lesson 3
GOALProvide a basic
understanding of how to protect natural resources beginning with
site preparation
LEARNING OBJECTIVES Identify some natural resources that
are protected in VI Identify the steps in initial site
preparation and ways to work “green” to protect our natural resources
1Work Green -
SITE PREPARATION
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Protect VI’s Natural Resources
7
The VI’s natural resources, such as native vegetation, water courses, and marine habitats, are afforded protections under existing Territorial and Federal regulations like the Coastal Zone Management Program and the Clean Water Act.
Other resources, such as the VI boa, St. Croix ground lizard, sea turtles, elkhorn and staghorn corals, and plants like mangroves, have additional special protections.
Photo Credit: http://www.stcroixhotelandtourism.com/ecotourism.php
St. Croix ground lizard
Photo Credit: http://soundwaves.usgs.gov/2010/04/
Photo Credit: http://www.earthsendangered.com/profile.asp?ID=9&sp=557
VI tree boa red mangroves
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Protect VI’s Natural Resources
8
In the project design phase, surveys of the site should have been conducted to determine what natural resources occur on the site. Areas to be protected on site should also be marked on the plans. Resource protection also includes installation and maintenance of all required BMPs for erosion, sediment, and runoff control and management.
Be sure you are aware of what threatened or endangered plants and animals look like and the steps you should take if you see them while working on site. Fines and even jail time are possible if you cause harm to these resources, so be sure to follow all permit special conditions to follow to protect these resources and to contact the resources agencies and your project team if in doubt.
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
9
1. Ensure approved, stamped permits are on site.
2. Contractor does a walk-through with HEO to review the marked-off footprint of the area to be disturbed AND to identify marked trees, setbacks, and other features where no disturbance should occur.
3. Ensure perimeter controls such as silt fencing are installed.
4. Study project plans to familiarize yourself with project phasing and map out what and where temporary and permanent stormwater and erosion and sediment controls are required on site.
5. Ensure you have the contractor’s contact number for questions that may arise as you grade the site
Strategies you should use to protect the natural resources on a site:
jlhare.com/about-j-l-hare-associates/
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
10
1. Ensure approved, stamped permits are onsite.
2. Contractor does a walk-through with HEO to review the marked-off footprint of the area to be disturbed AND to identify marked trees, setbacks, and other features where no disturbance should occur.
3. Ensure perimeter controls such as silt fencing are installed.
4. Study project plans to familiarize yourself with project phasing and map out what and where temporary and permanent stormwater and erosion and sediment controls are required on site.
5. Ensure you have the contractor’s contact number for questions that may arise as you grade the site
Strategies you should use to protect the natural resources on a site:
Group discusses erosion control strategy for site in the Fish Bay Watershed.
Photo Credit: Island Resources Foundation.
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
11
1. Ensure approved, stamped permits are onsite.
2. Contractor does a walk-through with HEO to review the marked-off footprint of the area to be disturbed AND to identify marked trees, setbacks, and other features where no disturbance should occur.
3. Ensure silt fences are properly installed around the perimeter of the site.
4. Study project plans to familiarize yourself with project phasing and map out what and where temporary and permanent stormwater and erosion and sediment controls are required on site.
5. Ensure you have the contractor’s contact number for questions that may arise as you grade the site
Strategies you should use to protect the natural resources on a site:
Multiple lines of silt fences and use of cut brush to help control erosion.Photo Credit: Island Green Building Association
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
12
1. Ensure approved, stamped permits are onsite.
2. Contractor does a walk-through with HEO to review the marked-off footprint of the area to be disturbed AND to identify marked trees, setbacks, and other features where no disturbance should occur.
3. Ensure perimeter controls such as silt fencing are installed.
4. Study project plans to familiarize yourself with project phasing and map out what and where temporary and permanent stormwater and erosion and sediment controls are required on site.
5. Ensure you have the contractor’s contact number for questions that may arise as you grade the site
Strategies you should use to protect the natural resources on a site:
Figure: http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=browse&Rbutton=detail&bmp=116&minmeasure=4
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
13
1. Ensure approved, stamped permits are onsite.
2. Contractor does a walk-through with HEO to review the marked-off footprint of the area to be disturbed AND to identify marked trees, setbacks, and other features where no disturbance should occur.
3. Ensure perimeter controls such as silt fencing are installed.
4. Study project plans to familiarize yourself with project phasing and map out what and where temporary and permanent stormwater and erosion and sediment controls are required on site.
5. Ensure you have contact numbers for the contractor, architect, and others on the project team who can answer any questions that may arise as you begin earth movement on the site.
Strategies you should use to protect the natural resources on a site:
Photo credit: Horsley Witten Group http://www.horsleywitten.com/
Guide to Green Building in the VI Lesson 1 – Site Preparation
Work Green – Before Any Earth Movement
14
Before beginning any earth change work on site, remember to check:
1. Project plans to be sure the physical characteristics of the site (soils, topography, hydrology, and vegetation) match the proposed best management practices (BMPs) for sediment and erosion control and management of runoff
2. 150 foot buffer or setbacks adjacent to shorelines, 25 foot buffers adjacent to ghuts or 30 feet from ghut centerline, whichever is greater, and 50-150 foot setbacks from ponds and wetlands are clearly marked on site
3. All trees and other vegetation to be preserved on site are clearly marked
4. The disturbance footprint for all construction activities is clearly marked on site
Goal is to prevent any runoff or sediment transport off site.
Guide to Green Building in the VI Lesson 1 – Site Preparation
Initial Steps in Site Preparation
Hand clear trails and small areas only using non-mechanical equipment
No mechanical clearing or machine clearing of any kind is allowed before a CZM permit and any required Federal permits for mechanical clearing and other site work (if area contains wetlands, ghuts, or other water bodies or is along the shoreline) are received
Preserve all trees at this time
Build sturdy fences, wood, or steel barriers around all vegetation to be protected from construction and construction equipment. Barriers should be placed such that tall equipment doesn’t injure branches. Roots should also be protected from excavation.
15
Guide to Green Building in the VI Lesson 1 – Site Preparation
Site Preparation
All site preparation must create minimum erosion, runoff, and sediment transport off site
All site preparation must minimize impacts to natural resources
A way to accomplish both of these goals is to clear vegetation ONLY in immediate area around the building footprint and to clear vegetation only when construction will begin as soon as the area is cleared.
16
Guide to Green Building in the VI Lesson 1 – Site Preparation
Key Points
17
1. All of VI’s natural resources should be protected and are afforded legal protections under Territorial and Federal regulations. However, there are some plants and animals (terrestrial and marine) that are afforded additional protections. You should be aware of whether or not these are found on your site and of any permit special conditions to protect these resources to avoid fines and other penalties.
2. It is important to work green before any earth change occurs by ensuring• stamped, approved, final copies of all permits and plans are
readily available on site• you do a walk through and review the marked disturbance
footprint and any areas and vegetation to be protected• Silt fences are in place around the perimeter• Familiarity with project phasing and all required temporary
and permanent BMPs
3. There are some important initial steps in site preparation that need to be followed to protect vegetation and other resources and ensure all stormwater and sediment is properly contained on site.
Guide to Green Building in the VI Lesson 1 – Site Preparation 18
Before Grading NotesYou have all required approved, stamped permits on site prior to beginning any mechanized work.
☐ ☐YES NO
You know what natural features need to be protected. You can identify protected plants and animals and know what to do if you see them on site during construction.
☐ ☐YES NO
You ensure the footprint of the area to be disturbed is clearly marked on site. Heavy equipment operators have done a walk-through to view limits of site disturbance and areas and vegetation to be preserved.
☐ ☐YES NO
You ensure silt fencing is correctly installed along perimeter. ☐ ☐
YES NOYou have built temporary barriers around all vegetation to be preserved on the site. ☐ ☐
YES NO
WORKING GREEN Site Preparation CHECKLIST
Guide to Green Building in the VI Lesson 1 – Site Preparation 19
Before Grading NotesYou have studied project plans and the physical characteristics of the site and made modifications to the best management practices (BMPs) to be used as necessary based on slopes and soils.
☐ ☐YES NO
You have studied project plans and are familiar with project phasing and the locations of temporary and permanent BMPs for sediment and erosion control and stormwater management.
☐ ☐YES NO
You have installed all required BMPs based on the project phasing prior to commencing any mechanized work.
☐ ☐YES NO
You have the project team’s contact numbers readily available for questions that may arise as you begin grading the site.
☐ ☐YES NO
WORKING GREEN Site Preparation CHECKLIST
Intro
Lesson 1
Lesson 2
Lesson 3
GOALProvide practical
strategies for protecting natural resources during earth change
and construction
LEARNING OBJECTIVES Describe the importance of BMPs
and what they do Identify different types of temporary
and permanent BMPs’ Identify how to properly install some
commonly used BMPs Identify maintenance requirements of
different types of BMPs
2Work Green - CONSTRUCTION
Guide to Green Building in the VI Lesson 2 - Green Construction
What is Erosion?
21
Erosion is the detachment of a portion of the soil profile or soil surface. This can occur by either the impact of raindrops, or by the shear forces of water flowing across the soil surface.
road covered with eroded sediment
eroding slopePhoto Credit: Sharon Coldren - The Coral Bay Watershed Management Project: Being a Partner and Building Partnerships.
Guide to Green Building in the VI Lesson 2 - Green Construction
Erosion Control Practices
Best Management Practices (BMPs) for erosion control hold soil in place and reduce the potential for soil to be removed by stormwater (mulching, riprap, seeding sodding, surface roughening).
The most effective erosion control practices are to preserve the existing vegetation and to replant cleared or bare areas quickly.
22
Guide to Green Building in the VI Lesson 2 - Green Construction
What is Sediment?
23
Eroded or exposed soil particles (sediment) can be transported by rainwater and deposited short or long distances downslope of their point of origin. The transport and deposition process is called sedimentation. Typical Forces in Soil Erosion
Figure: http://onlinemanuals.txdot.gov/txdotmanuals/hyd/soil_erosion_control_considerations.htm
Guide to Green Building in the VI Lesson 2 - Green Construction
Sediment Control Practices
BMPs for sediment control remove eroded soils from runoff before it leaves the property. These measures are not as effective as erosion control because most soils in the Virgin Islands are clay and most BMPs cannot remove clay from runoff.
It is much easier and more cost effective to keep soil in place than to attempt to remove it from stormwater.
Permanent sediment control practices are used to convey stormwater runoff to safe outlets away from erodible areas and/or treat stormwater runoff to remove sediment (brush berms, compost socks, silt fences, storm drain inlet protection, sediment traps, sediment basins). These practices need to be maintained over the project lifetime.
24
Guide to Green Building in the VI Lesson 2 - Green Construction
What is Runoff?
25
Surface runoff occurs when the soil is infiltrated to full capacity and excess water from rain or other sources flows over the land.
To reduce the potential for runoff and erosion, land clearing and earth change activities should NOT be planned during the rainy season.
road flooded with surface runoffPhoto Credit: Sharon Coldren - The Coral Bay Watershed Management Project: Being a Partner and Building Partnerships.
Guide to Green Building in the VI Lesson 2 - Green Construction
Runoff Control Practices
BMPs for runoff control maintain water on-site. Both conventional, structural stormwater controls and low impact development (LID) measures may be used to control runoff.
LID principles are based on controlling stormwater at the source by the use of controls that are distributed throughout the site (rain gardens, grass swales and channels, vegetated rooftops, rain barrels, cisterns, vegetated filter strips, and permeable pavement). This is unlike conventional approaches that typically convey and manage runoff in large facilities located at the base of drainage areas (check dams, grass-lined channels, permanent slope diversions, temporary diversion dikes).
26
Guide to Green Building in the VI Lesson 2 - Green Construction
Low Impact Development Ideas
27
Minimum driveway reduces runoff
Rain Garden keeps runoff on site
reinforced grass swale directs runoff
Your cistern collects rainwater and reduces water running off the site
Horsley Witten Group
www.tensar.co.uk/www.igbavi.org/
Photo Credit:Hosana Solomon
Guide to Green Building in the VI Lesson 2 - Green Construction
Low Impact Development Ideas
28
This is an example of the use of a gravel construction entrance at a residential construction site in Mt. Washington, St. Croix. The placement of gravel is temporary in order to prevent exposed dirt from eroding.
Photo credit: Horsley Witten Group http://www.horsleywitten.com/
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – During Rainy Season
Think about the rainy season as “Give Your Machine a Brake” season. Take the opportunity to travel, relax, and rest during hurricane season (August to November).
Keep yourself and your machinery safe by staying off unsafe slopes during heavy rains. Take the opportunity to get maintenance done to your equipment during this time and help us protect our natural resources from the impacts of sediment-laden runoff
29
Photo Credit: Sharon Coldren - The Coral Bay Watershed Management Project: Being a Partner and Building Partnerships.
Guide to Green Building in the VI Lesson 2 - Green Construction
BMP Selection Strategy
30
On any construction site, the objective of erosion and sediment control and runoff management is to prevent off-site transport of sediment and runoff.
BEFORE beginning earth change operations, be sure all required temporary and permanent erosion, sediment, and runoff BMPs have been installed.Typical uses and locations for erosion prevention and sediment control BMPs. (Source: Idaho Construction Site Erosion and Sediment Control Field Guide)
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – Beginning Earth Change
Once the project has all the required permits and they are posted on-site along with final, stamped plans, you are ready to begin the process of clearing the areas to be disturbed.
Plan ahead – AVOID excavation and other work that exposes bare soils during the rainy season. Sediment loading to nearshore waters, including coral reefs, has been shown to increase dramatically if work is done during wet periods because BMPs are not as effective due to the amount of runoff generated and the fact that work often has to stop during bad weather, leaving soils exposed.
The first step is to create berms and swales to contain runoff from cleared areas. Then you need to ensure all environmental protection measures are installed BEFORE beginning any mechanical site work.
31
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – Beginning Earth Change
As part of BMP installation, be sure to note the location of all existing storm drains on the site and create temporary diversions of these PRIOR to beginning any mechanical clearing
Diversions can be: a sediment trap below a permanent outfall an in-line diversion of an inlet or a manhole the installation of a retention basin early in the
construction sequence the delay of the completion of a permanent
outfall and the temporary diversion of runoff to a sediment trap
Additional inlet protections are not needed if diversions have been installed and are functioning properly 32
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – During Earth Change
Use smaller heavy equipment and minimize number and size of cuts on hillsides.
Erosion control measures must be installed as quickly as possible where construction has temporarily or permanently stopped for more than 14 days.
No excavation for footings, foundations, cisterns, wastewater treatment, etc. should be done if construction work will not begin within 14 days so as not to expose bare soils to rain and wind.
Use serrated cut slopes in areas where cuts will be steeper than 50% behind buildings and next to driveways and roads.
Use benches to break long (more than 20 to 40 foot) slopes and route runoff to a sediment trap or stabilized outlet.
33
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – During Earth Change
Make sure no grading impairs existing surface drainage, constitutes a potential erosion hazard, or acts as a source of sediment to ghuts. Respect all buffers, green belts, and setbacks and protect all native stream fauna, shorelines, and wetlands. Do not allow equipment, vehicles, or construction materials to cross or be stored in setbacks, buffers, or green belts.
34
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – Protect Vegetation
Start tunnels under root systems for underground utilities at least 18 inches below the ground surface.
Don’t pile more than 3 inches of soil over trees and shrub roots.
Use retaining walls or terraces to protect roots when lowering grades. Begin lowered grades outside tree drip-line. Don’t trench across roots within the drip-line (or trees could be weakened to the point of collapse).
35
Guide to Green Building in the VI Lesson 2 - Green Construction
Soil Stabilization During Earth Change
Stockpile and temporarily seed or cover topsoil with tarps or erosion control mats. Ensure all stockpile and borrow areas are shown on project plans.
When larger areas are to be cleared, run heavy equipment up and down slope to create grooves perpendicular to slope. This will channel runoff across slope instead of down to reduce erosion from gullying.
Compact all fills to reduce erosion, slippage, settlement, and subsidence.
Keep fill material free of brush, rubbish, rocks, logs, stumps, and building debris.
Provide adequate drainage for seeps and springs so excess water doesn’t lead to slope failure.
36
Guide to Green Building in the VI Lesson 2 - Green Construction
More on Soil Stabilization
Chemical sealers/binders are used to minimize dust and erosion from dirt roads, on very steep slopes or very dry soils, or on other areas where it is difficult to establish vegetation.
If using chemical sealers/binders, make sure they are environmentally safe
Mulch is also used to stabilize exposed soils. Examples of mulch are straw or hay, wood fiber (jute), mulch netting, crushed stone, or wood chips.Vegetated filter strips are another soil stabilization measure. Hydroseeding may be used to create these filter strips.
37
Guide to Green Building in the VI Lesson 2 - Green Construction
Save Brush & Boulders
38
Berms are placed to reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. These barriers are intended for use with small drainage areas up to one-quarter acre per 100 lineal feet of berm. They should not be used in high volume, high velocity flows.
Use brush from the site to make berms! (And save boulders for use in retaining walls, check dams, or other rock structures.)The vegetated part of branches should be placed in contact with the ground. Limbs should be layered to form a berm. Berm should be constructed in lifts with each layer extending the length of the berm prior to the next layer placement.
Figure: http://sddot.com/business/design/docs/wqep/Data_Sheets/BrushBerm.pdf
A brush berm is a barrier that consists of woody brush and branches less than 2 inches wrapped in filter fabric and anchored to the ground.
Guide to Green Building in the VI Lesson 2 - Green Construction
Brush Berm & Silt Fence Design Detail
39
Brush berms are regularly installed with silt fences on construction sites in the USVI. In the example on the right, cleared vegetation on a site in Coral Bay is used to construct a brush berm (18 inches high) that is designed to be installed 24 inches in front of a filter fabric fence (silt fence).
Figure: NOAA ARRA USVI Watershed Stabilization Project, Carolina Valley, St. John
Guide to Green Building in the VI Lesson 2 - Green Construction
Erosion Control Blanket Installation
40
1. Grade, disk, and prepare seedbed. Seed the area before blanket installation. For long slopes, install blankets up and down the slope face. For channels, install blankets parallel to flow of the channel, as per manufacturer’s directions.
2. Install the product starting from the top of the slope, anchored in a 6” x 6” trench that is backfilled and tamped firmly. Anchors/staples are “U” shaped and a minimum of 6 inches long. Longer staples are used in sandy soils.
Figure Credit: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Erosion Control Blanket Installation
41
3. Walk blankets down slope to ensure good contact with the soil. Staple blankets every 12 inches on tops and 18 to 36 inches down the sides and in the middle or according to manufacturer’s directions, whichever is more protective.
4. Do not stretch blankets.
5. Do not exceed manufacturer’s directions on maximum slope angle for the product.
6. Additional staking or stapling is needed for applications in channels that carry flowing water and on steep slopes. Inspect before and after each rain event and twice monthly until the tributary drainage area has been stabilized.
Figure Credit: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Sediment Control – Silt Fence
42
A silt fence is a temporary linear barrier that captures sediment by ponding stormwater runoff, allowing sediment to settle out.
A silt fence can be used along slopes, below exposed soil areas, and around temporary stockpiles. In general, each 100-foot section of silt fence treats runoff from approximately 1/4 acre (about 100 feet uphill). The runoff contained by each silt fence shouldn’t be from more than one acre. On slopes greater than 25%, install reinforced silt fences in rows 10-15 feet apart.
Figure: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Silt Fence Installation
43
1. Note the location and extent of the bare soil area. Mark silt fence location just below bare soil area. Make sure fence will catch all flows from area.
2. Dig trench a minimum of 6 inches wide and deep across slope.
3. Unroll silt fence along trench. Push geotextile into trench; spread along bottom and sides.
4. Drive posts on downhill side a maximum of 6 feet apart.
5. Secure silt fence to posts with staples, wire, or as recommended by manufacturer. If needed, join fencing by rolling the end posts together. Steel posts are the most effective because they will not be damaged by insects or rot. Reinforce fences with steel posts and wire mesh backing for steeper slopes.
6. Do not place joined sections in low spots or sump locations. Fill trench with soil and tamp down.
Figure: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Silt Fence Installation
44
Properly Installed Silt Fence Improperly Installed Silt Fence
This silt fence is correctly installed. The steel posts are installed on the downhill side. A wire mesh backing has been added for this steeper slope to prevent undercutting.
Reminder: A silt fence is a temporary linear barrier and is not designed to withstand high heads of water. A silt fence should NEVER be installed across drainage ways, ghuts, or channels.
This silt fence is incorrectly installed. The posts are installed on the uphill side of
the fence. The bottom of the fence also appears loose in several areas.
Adequate trenching and backfill is needed to ensure bottom of fence stays
in place.
Photo Credit: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Sediment Control – Compost Sock
45
Compost socks can be used as an alternative to silt fencing and also work well to protect storm drain inlets.
They function by intercepting runoff, reducing runoff flow velocity, ponding runoff, allowing sediment to settle out, and releasing the runoff as sheet flow. Compost socks cannot be used on slopes greater than 2:1. Compost socks can be created using materials from site clearing.
Figure: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Compost Sock Installation
46
1. Install along contours starting at the toe of the slope, or slightly away from the toe, and every 3 to 30 feet along the slope depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the compost socks should be.
2. Compost socks shall not be used on slopes greater than 2H:1V.
3. Use only cured or finished compost.
4. Compost socks shall be filled so they are firmly packed yet flexible. Once placed on the ground, apply temporary weight to the sock to improve contact with the underlying surface. This may cause the sock to assume an oval shape.
Figure: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Compost Sock Installation
47
5. Install stakes at each end of a compost sock, and at 3-foot centers along the entire length. If required, install pilot holes through the compost sock and into the soil prior to installing stakes. Stakes should be installed perpendicular to the ground surface and on a slight angle alternating left to right. The stakes at angle prevent the sock from lifting or floating during the first rain event.
6. Wooden stakes should be 2” x 2” x 36” minimum. Cut branches or 3/4 inch rebar can also be used as stakes.
7. If more than one compost sock is installed in a row, tightly abut end to end the two adjoining socks.
8. Turn ends of compost socks uphill to prevent water from flowing around the barrier.
Figure: Idaho Construction Site Erosion and Sediment Control Field Guide
Guide to Green Building in the VI Lesson 2 - Green Construction
Protecting Storm Drains & Other Inlets
48
Muddy runoff that flows toward a culvert, ditch, or storm drain inlet must be slowed down and pooled or filtered to settle out and remove sediment. This can be accomplished by excavating, placing rock, reinforced silt fencing, silt dikes, stone or blocks, or other barriers or curb drops in front of the inlet.
All of these choices can handle runoff from a 1-acre drainage area maximum.
The goal is to cause ponding so sediment can settle out before ponded water enters the inlet.
Photo Credit: http://www.ars.usda.gov/is/pr/2010/100723.htm
Filter socks containing compost tucked into mesh tubes are used to keep some of the silt, heavy metals, fertilizers, and petroleum products washed from compacted surface areas from going into nearby waterways.
Guide to Green Building in the VI Lesson 2 - Green Construction
Protecting Inlets
49
The inlet shown above is not properly protected. The geotextile does a poor job of helping to slow and pool runoff. The material is also difficult to remove when filled with sediment.
The inlet shown above is adequately protected. Gravel
bags will help to slow and pool runoff. Accumulated sediment can
be easily removed.
Guide to Green Building in the VI Lesson 2 - Green Construction
Protecting Outlets
50
Outlet protection prevents scour and erosion at outlets by reducing the depth, speed, and energy of concentrated stormwater flows. Outlet protection should be installed at the outlets of culverts, ditches, storm drains, piped slope drains, and any channels that discharge into natural waterways or constructed channels.
Outlet protection can be stone, rip rap, grouted rip rap, or gabions.
Outlet protection is made by placing rip-rap, which is large, angular rock, at the outlet of conveyance channels, sediment traps, or pipes. This practice slows down and spreads water out, thereby preventing erosion at the point of discharge.
Photo Credit: http://www.aiswcd.org/IUM/standards/urbst910.html
Guide to Green Building in the VI Lesson 2 - Green Construction
Sediment Control – Temporary Sediment Basin
51
• A settling pond with a controlled stormwater release outlet is used to collect and store sediment produced by construction activities.
• Sediment storage volume must be at least 3,600 cubic feet per acre of disturbed area draining to basin.
• Built by excavation and/or by placing an earthen embankment across low areas, drainage channels, or swales.
• Can be designed to maintain a permanent pool or to drain completely dry. They are used for drainage areas of 10-20 acres.
Figure: http://www.cep.unep.org/pubs/Techreports/tr32en/content.html
Small sediment basin with outlet pipe discharging on riprap to prevent erosion at discharge end
Guide to Green Building in the VI Lesson 2 - Green Construction
Sediment Control – Temporary Sediment Basin
52
Installation of a sediment trap at Whispering Hills Affordable Housing Construction Site, St. Thomas East End.Photo credit: Frank Galdo
Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green - Driveways
All driveways should be surfaced with pavement or permeable pavers after grading is complete. Gravel should not be used to permanently pave areas, especially where there are steep slopes. Gravel driveways on steep slopes contribute to erosion and gullying by stormwater, although their contribution is less than that of unpaved roads.
Exposed earth driveways or driveway cuts should not remain unstabilized for more than 30 days after their creation. Soil stabilization (mattings, temporary seeding, etc.) is required during and after construction
A silt fence, even if properly installed, is not enough to manage erosion and stormwater runoff from unpaved driveways
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Guide to Green Building in the VI Lesson 2 - Green Construction
Work Green – Construction Entrances
A stabilized construction entrance should be installed at every entrance/exit to prevent soil from being tracked or washed off site to public roadways.Guidelines: Minimum 30 foot length for single residential lot, 50 foot for
other sites 10 to 12 foot minimum width flare at existing road for
turning Filter fabric placed over existing ground surface prior to
placing stone (although may not be necessary for individual home site)
Place 2 – 3 inches of crushed aggregate at least 6 inches deep over length and width of entrance
Pipe all surface water flowing to or diverted toward construction entrances and protect pipe with a berm. Size pipe according to drainage area with minimum 6 inch diameter or use a 5:1 slope berm if piping is impractical
Regularly maintain54
Guide to Green Building in the VI Lesson 2 - Green Construction
BMP Maintenance
In order for BMPs to be effective, they must be maintained during construction and during the project lifetime if the BMPs are permanent. The following are maintenance practices that need to be followed for different BMPs: Filter strips – maintain edges to prevent the formation of
concentrated flows, mow, do spot repairs of vegetation Temporary seeding/hydroseeding – complete spot repairs by
reseeding/mulching, mow grass swales and embankments Sediment traps – remove sediment when accumulation is to
½ of design depth, repair embankments and rock filters Temporary sediment basins – repair damage from soil
erosion and construction equipment at or before end of each work day, clean basins when they are at 50% fill by volume or when sediment is within 1 inch of bottom of the principal spillway crest
Silt fences – replace any failed stakes, clear accumulated sediments behind fences, replace hay bales that have been placed upslope of fences regularly
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Guide to Green Building in the VI Lesson 2 - Green Construction
BMP Maintenance – Sediment Disposal
For all BMP maintenance related to sediment control, be sure all accumulated sediment that is removed from traps, settling basins, etc. is disposed of properly.
NEVER dispose of sediments downstream from an embankment (natural or part of a BMP), adjacent to a drainageway, or in a floodplain.
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Guide to Green Building in the VI Lesson 2 - Green Construction
Key Points
57
1. BMPs are used to manage erosion, sediment, and runoff. The most effective measure is to minimize site disturbance and phase earth change work so that exposed soils can be stabilized quickly.
2. BMPs can be temporary or permanent. All measures need to be in place before earth change begins.
3. Ensure silt fences, erosion control blankets, and other BMPs are properly installed to ensure all sediment from your project is retained on site and runoff off site is minimized. Make sure you have included construction entrance/exit sediment controls.
4. BMPs require regular maintenance to be effective. Be sure sediment that is cleaned from sediment control BMPs is properly disposed of and that BMP maintenance is part of your regular work schedule on site.
Guide to Green Building in the VI Lesson 2 - Green Construction 58
During Construction NotesYou have planned required excavation and other earth movement work that results in exposed soils for completion outside the rainy season.
☐ ☐YES NO
You have ensured that all sediment and erosion control and stormwater BMPs are properly installed BEFORE beginning any mechanized work on-site. This includes stabilized construction entrances.
☐ ☐YES NO
You have created berms and swales to contain runoff from cleared areas as you begin site clearing and grading. Brush from the site can be used to create berms and boulders can be used for more permanent structures such as retaining walls.
☐ ☐YES NO
You have installed temporary diversions of existing storm drains BEFORE beginning any site clearing.
☐ ☐YES NO
WORKING GREEN Construction CHECKLIST
Guide to Green Building in the VI Lesson 2 - Green Construction 59
During Construction NotesYou ensure no excavation work will begin if soils will be exposed for 14 days or more. ☐ ☐
YES NO
If there is a construction stoppage that has already lasted 14 days, you install erosion control measures IMMEDIATELY to minimize erosion of exposed soil.
☐ ☐YES NO
You create serrated cut slopes if cuts are steeper than 50% behind buildings and next to driveways and roads.
☐ ☐YES NO
You construct benches to break slopes of more than 20 to 40 feet and route runoff to a sediment trap or stabilized outlet to minimize sediment and runoff transport offsite.
☐ ☐YES NO
You do not cross or store equipment, vehicles, or construction materials in setbacks, buffers, or green belts.
☐ ☐YES NO
WORKING GREEN Construction CHECKLIST
Guide to Green Building in the VI Lesson 2 - Green Construction 60
During Construction NotesYou protect vegetation by tunneling under roots to install utilities, avoiding piling excess soil on and around roots, and building retaining walls or terraces.
☐ ☐YES NO
You ensure that all soil stockpiles are covered to prevent erosion of material during rains.
☐ ☐YES NO
When large areas need to be cleared, you run heavy equipment up and down slope to create grooves and channel runoff across the slope to minimize gully formation.
☐ ☐YES NO
You compact all fill material and use fill that is free of vegetative and construction debris to ensure it can be well compacted.
☐ ☐YES NO
You ensure all BMPs are properly maintained as part of daily construction activities and a regular maintenance schedule.
☐ ☐YES NO
WORKING GREEN Construction CHECKLIST
Intro
Lesson 1
Lesson 2
Lesson 3
GOALProvide practical
strategies for protecting natural resources at the conclusion of
the project
LEARNING OBJECTIVE Describe process of final site
stabilization and landscaping Describe BMP maintenance
requirements and process for removal of temporary BMPs
3Work Green -
PROJECT COMPLETION
Guide to Green Building in the VI Lesson 3 – Project Completion
Work Green – Final Site Stabilization
Once construction is complete, your site needs to be permanently stabilized and landscaped following the project plans.
Complete all permanent seeding and planting, final retaining walls on cut or steep slopes that cannot be planted (use boulders from site clearing in walls). Install porous pavers to reduce erosion and stormwater runoff and rain gardens (also called bioretention ponds) to help absorb rainwater on site. 62
Photo Credit: Island Green Building Association
Rain Garden in Hope & Carton neighborhood, St.
CroixPhoto Credit: Michelle West, Horsley Witten Group
Minimum driveway reduces runoff
Guide to Green Building in the VI Lesson 3 – Project Completion
Remove Temporary BMPs
Temporary sediment basins - should be removed at the end of their lifetime once construction is complete as part of final site grading and after the drainage area has been stabilized. Level embankments and properly dispose of sediments at approved upland site. 63
Sediment traps – regrade and plant areas where temporary sediment traps were installed after all construction is complete and as part of the restoration of stormwater drainages.
Temporary sediment trap at Cocoloba Trail
Temporary sediment trap at John Head Road
Photo Credit: Island Resources Foundation. Erosion Control Strategy for the Fish Bay Waters.
Guide to Green Building in the VI Lesson 3 – Project Completion
Remove Storm Drain Diversions
Once areas contributing sediment have been stabilized, the permanent storm drainage system should be restored.
Remove all accumulated sediment. Establish permanent, stabilized outfall channel based on project plans.
Where inlet was modified, plug temporary pipe stub and open the permanent outfall pipe
Remove temporary sediment control devices for traps that will be converted to stormwater management
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Guide to Green Building in the VI Lesson 3 – Project Completion
Maintenance Requirements
Seed/Sod – repair bare spots by reseeding and/or mulching, mow grass frequently to control weeds (at least 2 inches above ground during wet season and longer during dry season)
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Rain garden/bioretention ponds – inspect monthly until plants establish then inspect annually, replant as needed, remove sediment from behind check dams when accumulations reach ½ dam depth
runoff control maintenance
Volunteers help clean out a clogged runoff drainage structure in Fish Bay
Photo Credit: Island Resources Foundation. Erosion Control Strategy for the Fish Bay Watershed.
Guide to Green Building in the VI Lesson 3 – Project Completion
Maintenance Requirements
66
This is a stormwater retention basin in Kingshill Road, Coral Bay, St. John. Sediment needs to be removed or else erosion control function of the basin is lost.
Evident sediment build up in retention pond located along Kingshill Road, Coral Bay, St. John. Removal of excess sediment is important to maintain proper function of the pond.
Photo credit: Horsley Witten Group http://www.horsleywitten.com/
Guide to Green Building in the VI Lesson 3 – Project Completion
Key Points
67
1. As part of the completion of construction on your site, finalize all grading, slope and cut stabilization, and landscaping
2. Remove temporary BMPs and provide maintenance to permanent BMPs
3. Restore and complete stormwater drainage system according to site plans for your project
Guide to Green Building in the VI Lesson 3 – Project Completion 68
After Construction Notes
You complete final site stabilization, including all permanent seeding and planting and the construction of final retaining walls on cut or steep slopes, as part of final site grading.
☐ ☐YES NO
You remove all temporary BMPs and properly dispose of all accumulated sediments on uplands away from ghuts and other wetlands and water bodies.
☐ ☐YES NO
You restore the permanent stormwater drainage system, including the removal of all storm drain diversions.
☐ ☐YES NO
You have ensured the site owner is aware of the maintenance requirements for permanent BMPs and have assisted in creating a maintenance schedule for the property if one was not included as part of project design.
☐ ☐YES NO
WORKING GREEN Project Completion CHECKLIST
Guide to Green Building in the VI Lesson 3 – Project Completion
Learn More
69
BMPs for Stormwater Management
Photo Credit: Michelle West, Horsley Witten Group
Constructing a Native Soil Rain Garden http://www.caes.uga.edu/extension/water/lc/documents/ConstructingaNativeSoilRainGarden.pdf
National Menu of Stormwater Best Management Practiceshttp://cfpub.epa.gov/npdes/stormwater/menuofbmps/
BMPs for Sediment & Erosion Control
Sediment & Erosion Control on Construction Sites http://www.coralreef.gov/transportation/sederosuvi.pdf
Virgin Islands Environmental Protection Handbook. 2002. http://dloc.com/CA01300680/00001
LEED for Contractors, Construction Activity Pollution Preventionhttp://www.leedforcontractors.com/filling-out-the-leed-online-scorecard/construction-activity-pollution-prevention
US Green Building Council http://usgbccaribbean.org/
Rain Garden in Hope & Carton neighborhood, St.
Croix
Guide to Green Building in the VI Acknowledgements
Acknowledgements
70
Steering Committee
Department of Planning & Natural Resources Alex Holecek, Program Analyst - Division of Coastal Zone ManagementJean-Pierre Oriol, Director – Division of Coastal Zone ManagementRoy A. Pemberton Jr, Director Division of Fish and WildlifePhillip Smith, Director - Division of Building Permits
Island Green Building AssociationBarry DevineKaren VahlingWilliam Willigerod
NOAA's Coral Reef Conservation Program, OCRMMarlon Hibbert, USVI Management Liaison
NOAA FisheriesLisamarie Carrubba, Protected Resources DivisionLia Ortiz, Coral Reef Conservation Program USVI Fishery LiaisonGlenis Padilla, Coral Reef Conservation Program Biologist
US Army Corps of EngineersEdgar Garcia
U.S. Fish and Wildlife ServiceFelix Lopez
Green Building Council, Caribbean ChapterBrenda Martinez
OthersHorsley-Witten Group, Sharon Coldren and Coral Bay Community Council, Island Green Building Association,
Photo Credits The photos used on the cover slide and section introductions were obtained from the following sources: www.dpnr.gov.viwww.solarsystemsvi.com