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Los Alamos National Laboratory
Storm Water BMP Manual
LAUR-
Revision 0: March 2011
Prepared by: ENV-RCRA
Los Alamos National Laboratory
Blank pages in document are for duplex printing purposes.
TABLE OF CONTENTS
Table of Contents……………………………………………………………………………………………………………. i
Acronyms………………………………………………………………………………………………………………………. ii
1.1. Introduction (how to use this guidance document)……………………………………….. 1
1.2. Best Management Practice Use Matrix……………………………………………………… 3
1.3. LANL Considerations……………………………………………………………………………. 5
1.4. References………………………………………………………………………………………… 7
2.1. Good Housekeeping…………………………………………………………………………….. 9
2.2. Scheduling Practices…………………………………………………………………………… 13
3.1. Silt Fence and S-Fence……………………………………………………………………….. 17
3.2. Fiber Rolls…………………………………………………………………………………………. 23
3.3. Triangular Silt Dike……………………………………………………………………………… 27
3.4. Construction Entrance/Exit……………………………………………………………………. 35
3.5. Brush Barrier……………………………………………………………………………………… 39
3.6. Storm Drain Inlet Protection………………………………………………………………….. 43
4.1. Berms and Channels…………………………………………………………………………… 49
4.2. Check Dams……………………………………………………………………………………… 57
4.3. Waterbars and Runouts……………………………………………………………………….. 61
4.4. Terracing………………………………………………………………………………………….. 65
4.5. Surface Roughening…………………………………………………………………………… 71
4.6. Sediment Traps………………………………………………………………………………… 77
4.7. Storm Water Detention Basins………………………………………………………………. 81
5.1. Revegetation…………………………………………………………………………………….. 87
5.2. Temporary Stabilization……………………………………………………………………….. 91
5.3. Rolled Erosion Control Products (RECP)…………………………………………………. 95
5.4. Dust Suppression……………………………………………………………………………….. 99
5.5. Gabions………………………………………………………………………………………….. 101
5.6. Riprap……………………………………………………………………………………………. 105
5.7. Permanent Capping………………………………………………………………………….. 109
ACRONYMS
AOC Area of Concern
BFM Bonded Fiber Matrix
BMP Best Management Practice
CGRP Cerro Grande Rehabilitation Project DOE Department of Energy
ECB Erosion Control Blanket
EM&R Emergency Management & Response ENV-RCRA LANL Water Quality Group
EPA Environmental Protection Agency
FGM Flexterra or other Flexible Growth Medium HDPE High Density Polyethylene
IECA International Erosion Control Association LANL Los Alamos National Laboratory
MgCl Magnesium chloride
MSGP Multi-Sector General Permit
MSS Maintenance and Site Services
NM New Mexico
NMED New Mexico Environment Department NOI Notice of Intent
NPDES National Pollutant Discharge Elimination System PAM Polyacrylamide
RECP Rolled Erosion Control Product
SPCC Spill Prevention Control and Countermeasure SWMUs Solid Waste Management Units
TRM Turf Reinforcement Mat
TSD Triangular Silt Dike
UV Ultraviolet
WMC Waste Management Coordinator
ii
This guidance document was developed to provide information on the selection, function, installation, inspection, and maintenance of Best Management Practices (BMPs) for storm water management, sediment and erosion control and the management of other potential surface water pollutants at Los Alamos National Laboratory (LANL). Its intent is to provide a consistent approach in the selection and use of BMPs at LANL. The information provided in this document is not intended to replace an engineering design where such designs may be applicable, but should be used in support of and in conjunction with the LANL Engineering Standards and specifications. This document is also not inclusive of all the BMPs that may be applicable at LANL.
WHAT IS A BMP?
HOW TO USE THIS GUIDANCE DOCUMENT
BMPstands for Best Management Practice.
BMPscan be procedures, practices, or physical structures or controls.
BMPsminimize the potential for pollutant transport.
BMPscan be either temporary or permanent.
The BMPs identified in this manual are common industry practices, are types or categories that can be utilized with a variety of “off the shelf” products, and are those that have proven effective for LANL conditions and climates.
However, the BMP industry is dynamic. New products and innovations are continually being introduced. If new or modified BMPs not identified in this guidance document are identified or desired for use, the LANL Water Quality & RCRA Group (ENV-RCRA) should be consulted for guidance and approval. Installation of manufactured BMPs should follow installation guidance and recommendations as provided by the manufacturer.
This manual is organized in the following sections:
Section |
Purpose |
|
1 – |
LANL Considerations |
Local and State standards, specifications, and concerns |
2 – |
Good Housekeeping and Scheduling Practices |
Practices and administrative controls to minimize potential pollutant contact with storm water |
3 – |
Sediment Controls |
Retain sediment onsite |
4 – |
Runon/Runoff Control |
Minimize erosion and sediment transport by reducing runoff velocity and minimizing potential pollutant contact with storm water |
5 – |
Erosion Controls |
Prevent erosion from starting |
Construction Sites/Activities
MSGP
Facilities
Individual Storm Water Permit / Solid Waste Management Units
(SWMUs)
Best Management Practice Use Matrix
|
|
Location |
Purpose |
Properties |
||||||||||
BMP |
Page(s) |
Drainage Area Size (Acre) |
Slopes > 3:1 |
Use on Flat Terrain/ Slopes <3:1 |
Impervious Surface |
Use in Channels |
Erosion Control |
Sediment Retention |
Dust Control |
Divert Flow |
Reduce Flow Velocities |
Longevity |
Installation/ Design |
Cost |
Silt Fence |
17 |
|
Y |
Y |
|
|
|
Y |
|
|
|
1 Season |
Easy |
Low |
Floc Logs |
23 |
|
|
Y |
|
Y |
|
Y |
|
|
|
Temporary |
Moderate |
Med |
Gravel bags |
23 |
|
Y |
Y |
Y |
Y |
|
Y |
|
Y |
Y |
1 to 2 Years |
Easy |
Low |
Wattles/Coir logs |
23 |
|
Y |
Y |
|
|
|
Y |
|
Y |
Y |
1 to 2 Years |
Easy |
Low |
Triangular Silt Dike |
27 |
|
|
Y |
|
Y |
|
Y |
|
Y |
Y |
1 to 2 Years |
Easy |
Low to Med |
Construction Entrance/Exit |
35 |
|
|
Y |
Y |
|
Y |
Y |
|
|
|
Temporary |
Easy |
Med |
Log Berm and Brush Barriers |
39, 49 |
|
|
Y |
|
|
|
Y |
|
Y |
Y |
Temporary |
Easy |
Low |
Inlet Protection |
43 |
|
|
Y |
Y |
Y |
|
Y |
|
|
Y |
Temporary to Permanent |
Easy |
Low |
Sand Bags |
43 |
|
Y |
Y |
Y |
Y |
|
Y |
|
Y |
Y |
Temporary |
Easy |
Med |
Berms |
49 |
|
|
Y |
|
|
Y |
Y |
|
Y |
|
Temporary to Permanent |
Easy |
Low to Med |
Rock Check Dams |
57 |
|
|
Y |
|
Y |
|
Y |
|
|
Y |
Temporary or Permanent |
Easy |
Low |
Waterbars and Runouts |
61 |
|
|
Y |
|
Y |
|
Y |
|
Y |
Y |
Temporary to Permanent |
Easy |
Low |
Terracing |
65 |
|
Y |
Y |
|
Y |
Y |
|
|
|
Y |
Temporary to Permanent |
Easy |
Low |
Surface roughening |
71 |
|
Y |
Y |
|
Y |
Y |
|
|
|
Y |
Temporary to Permanent |
Easy |
Low |
Sediment Traps |
77 |
|
|
Y |
|
Y |
|
Y |
|
|
Y |
Temporary to Permanent |
Moderate to difficult |
Med |
Storm water detention basin |
81 |
|
Y |
|
|
Y |
Y |
Y |
|
|
Y |
Temporary to Permanent |
Difficult |
Med to High |
Flexterra (FGM) |
87 |
|
Y |
Y |
|
|
Y |
|
Y |
|
|
Temporary |
Moderate |
Med |
Hydromulch |
87 |
|
Y |
Y |
|
|
Y |
|
Y |
|
|
Temporary |
Moderate |
Med |
Seeding |
87 |
|
Y |
Y |
|
Y |
Y |
|
Y |
|
|
Temporary to Permanent |
Moderate |
Low |
Mulch |
87 |
|
|
Y |
|
|
Y |
|
Y |
|
|
Temporary |
Easy |
Low |
Tackifiers |
91 |
|
Y |
Y |
|
|
Y |
|
Y |
|
|
Temporary |
Easy |
Med |
Turf Reinforcement Mats |
95 |
|
Y |
Y |
|
Y |
Y |
|
Y |
|
Y |
Permanent |
Can be difficult on Steep Slopes |
Med |
Erosion Control Blankets |
95 |
|
Y |
Y |
|
|
Y |
|
Y |
|
|
1-2 years |
Can be difficult on Steep Slopes |
Med |
Gabions |
101 |
|
Y |
Y |
|
Y |
Y |
|
|
|
Y |
Permanent |
Difficult |
Med to High |
Rip Rap |
105 |
|
Y |
Y |
|
Y |
Y |
|
|
|
Y |
Permanent |
Moderate |
Med |
Outlet Protection |
101, |
|
Y |
Y |
|
Y |
Y |
|
|
|
Y |
Temporary to |
Easy to |
Low |
105 |
Permanent |
Moderate |
||||||||||||
Permanent Capping |
109 |
|
|
Y |
|
|
Y |
|
|
|
|
Permanent |
Difficult |
High |
LANL CONSIDERATIONS
LANL ENGINEERING STANDARDS
The Los Alamos National Laboratory Engineering Standards are comprised of several mandatory Functional Series documents including the Engineering Standards Manual (ESM), master guide specifications, standard details, example drawings, and a drafting manual. The purpose of the Engineering Standards is to define the minimum technical requirements for the design and construction of new and existing structures at LANL.
This Manual should supplement and support use of the Engineering Standards. As specified in their respective sections, storm water detention basins, riprap, and permanent capping must be designed using the Engineering Standards to ensure proper function of these BMPs. The Engineering Standards are also to be used in the design and construction of berms and check dams in excess of two feet in height.
Additionally, if the failure of a BMP has the potential to cause injury, loss of life, or property damage, the Engineering Standards would supersede the use of this document and the Standards should then be applied in the design and specification of the BMP. The Engineering Standards would provide design procedures and criteria associated with but not limited to:
When utilizing the LANL Engineering Standards for BMP design, the ESM and the master guide specifications should both be used. The ESM can be found at http://engstandards.lanl.gov/ESM_Chapters.shtml#esm3, and the master guide specifications are found at http://engstandards.lanl.gov/specs.shtml. For additional guidance on the applicability of the Engineering Standards for BMP design, contact the LANL Water Quality Group (ENV-RCRA).
SWMUs and AOCs
SPCC Plans
As per the LANL procedures and EPA Regulations, any facility or Project with a total aboveground storage capacity greater than 1,320 gallons with a minimum container size of 55 gallons must have a Spill Prevention Control and Countermeasures (SPCC) Plan. This includes not only diesel storage tanks, but also equipment such as compressors and drill rigs.
Contact the LANL Water Quality Group (ENV-RCRA) for guidance and support.
STATE REQUIREMENTS
Velocity Dissipation For soil disturbing activities subject to NPDES Construction General Permit coverage, State requirements mandate that runoff velocity from a construction project cannot increase from pre-development rates. Pre-development is defined as prior to any original disturbance. Install velocity dissipation devices such as check dams and detention ponds. Sites over 10 acres must install storm water detention ponds.
Sediment Yield For soil disturbing activities subject to NPDES Construction General Permit coverage, State requirements mandate that sediment yield from a construction project cannot increase from pre-development rates. Stabilize disturbed areas and utilize appropriate erosion controls.
Liquid Discharges onto the Ground
Request assistance from the LANL Water Quality Group (ENV-RCRA) to gather and submit information for preparation of a NMED Notice of Intent to Discharge (NOI) or LANL Un-permitted Liquid Discharge Log Report.
Examples: planned potable water, storm water drainage from secondary containment units, fire suppression test/flush, steam condensate, fire hydrant flush, pothole water, waterline disinfect/flush, land application of groundwater.
REFERENCES
LANL ENGINEERING STANDARDS AND CONSTRUCTION SPECIFICATIONS
http://engstandards.lanl.gov/
LANL CONSTRUCTION ACTIVITIES COMPLIANCE
http://int.lanl.gov/environment/h2o/cw_npdes.shtml
EPA CONSTRUCTION BMP MENU
http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=min_m easure&min_measure_id=4
EPA NPDES CONSTRUCTION GENERAL PERMIT (2008)
http://www.epa.gov/npdes/pubs/cgp2008_finalpermit.pdf
EPA NPDES MULTI-SECTOR GENERAL PERMIT (MSGP) (2008)
http://www.epa.gov/npdes/pubs/msgp2008_finalpermit.pdf
EPA NPDES INDIVIDUAL PERMIT – NM0030759 (2010)
ftp://ftp.nmenv.state.nm.us/www/swqb/NPDES/Permits/NM0030759- LANLStormwater.pdf
INDUSTRY ORGANIZATIONS
Land and Water Magazine http://www.landandwater.com/
Stormwater Magazine http://www.stormh2o.com/
IECA http://www.ieca.org/
The International Erosion Control Association (IECA) is devoted to helping solve the problems caused by erosion and its byproduct—sediment.
Good Housekeeping
Description Good housekeeping includes controls that are practices (as opposed to structural controls) that are used to reduce or prevent pollutants.
Applications Low cost alternative to structural BMPs.
Limitations Only prevents the initial migration of pollutants from the source.
Performance and Longevity
Design and Construction Guidance
In general, use of practices to prevent pollutants from contact with storm water is extremely effective.
Good housekeeping practices are implemented before project activities begin and throughout project activities. These practices are temporary in nature and are only meant to last through the construction activity process.
Performance |
Poor or N/A |
Good |
Excellent |
Erosion Prevention |
x |
|
|
Sediment Control |
x |
|
|
Runoff Control |
x |
|
|
Good Housekeeping |
|
|
x |
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Good housekeeping |
x |
|
|
|
Material storage
Wastes
Material Transport or Movement
Vehicle and Equipment Refueling & Maintenance
Vehicle and equipment control techniques include:
Potholing
Concrete Washouts
Concrete washouts should be used to contain concrete and liquids when rinsing equipment used for mixing or delivering concrete, or for excess concrete. They consolidate solids for easier disposal and prevent contaminated water from mixing with runoff.
Street Sweeping
Street sweeping and vacuuming includes use of self-propelled and walk-behind equipment to remove sediment from streets and roadways.
Inspection and Maintenance
What not to do…
Sweeping without vacuuming causes severe dust migration leading to sediment transport offsite.
Improper waste disposal and storage of waste products.
Containerize and separate waste items for proper disposal.
Scheduling Practices
Description Scheduling practices are controls that are practices (as opposed to structural controls) that are used to reduce or prevent pollutants.
Applications Low cost alternative to structural BMPs.
Limitations Only prevents the initial migration of pollutants from the source.
Performance and Longevity
In general, use of practices to prevent pollutants from contact with storm water is extremely effective.
Scheduling practices are implemented before project activities begin. These practices are temporary in nature and are only meant to last through the construction activity process.
Performance |
Poor or N/A |
Good |
Excellent |
Erosion Prevention |
x |
|
|
Sediment Control |
x |
|
|
Runoff Control |
x |
|
|
Good Housekeeping |
|
|
x |
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Scheduling Practices |
x |
|
|
|
Design and Construction Guidance
Downstream Impacts
Consider ways to ensure that runoff from your project does not affect sensitive locations downstream of your project such as wetlands, archaeological sites, Threatened and Endangered Species habitat, or SWMUs.
Timing Considerations
The timing and sequencing of soil disturbing activities can also be utilized as a BMP.
Construction site phasing involves disturbing only part of a site at a time to minimize erosion and runoff from inactive parts.
Preservation of Existing Vegetation
Reusable BMPs
Reduce waste at the Lab by utilizing reusable BMP products such as S-Fence,
Eco-Blok, Gravel Bags, Triangular Silt Dike, and construction entrance tracking devices. These products can be re-used over and over again and moved between jobs.
Spill Prevention, Response and Reporting
Spill Prevention includes inspecting equipment regularly for safety, cleanliness and leaks; and implementation of appropriate controls. Equipment found to be leaking should be removed from service and repaired. When possible, park equipment on asphalt or concrete to minimize generation of waste materials caused by spills on soil.
If a spill occurs, the following procedures shall be followed:
WHO |
Contact Responsibilities |
Response Duties |
Onsite workers |
Contact EM&R at 7-6211 or 911 if necessary |
Qualified workers may, but are not required to, clean up simple/small spills |
EM&R |
If EM&R is notified of a spill event, they will contact all additional applicable parties including ENV- RCRA |
Respond per contingency plan |
ENV-RCRA Water Quality |
Completion of spill reports that are reportable to federal and state agencies. Provide oversight for spill mitigation activities. |
Provide information to federal and state agencies. |
Disposal occurs by the Waste Management Coordinator (WMC) per LANL Procedure P409 Waste Management http://policy.lanl.gov/pods/policies.nsf/MainFrameset?ReadForm&DocNum=P40 9&FileName=P409.pdf.
Inspection and Maintenance
ENV-RCRA will complete required state, federal, and DOE Order 231.1A ORPS reporting requirements, in accordance with Laboratory and DOE policies and federal and state regulatory reporting requirements per P 322-3 Manual for Communication, Investigation, and Reporting Abnormal Events https://policy.lanl.gov/pods/policies.nsf/MainFrameset?ReadForm&DocNum=P3 22-3&FileName=P322-3.pdf.
16
Silt Fence and S-Fence™
Description Silt fences are typically used as temporary perimeter controls around sites where construction activities will disturb the soil. They can also be used within the interior of a site. A silt fence consists of a length of woven, permeable geotextile, stretched
between anchoring posts spaced at regular intervals along the site at low/downslope areas. The filter fabric should be entrenched in the ground between the support posts. When installed correctly, silt fences create ponding of runoff from the site, allowing transported sediment to settle out. Silt fences can be an effective barrier to sediment leaving the site.
The S-Fence is made from HDPE material and is much stiffer than the silt fence material. It is buried 3 inches in the ground and can be secured to an existing chain link fence or can be installed by itself and fastened to wood stakes. Each section is 7 feet long and comes in two heights: 10 inch and 14 inch. S-Fence is designed to allow water to flow through it and significantly reduces erosive energy and provides particle filtering.
Applications Silt fences apply to construction sites with relatively small drainage areas. They are appropriate in areas where runoff will occur as sheet flow. The drainage area for silt
fences should not exceed 0.25 acre per 100-foot fence length. Silt fence should not be used for runoff velocity control or placed in areas of concentrated runoff such as drainage channels and storm drain inlets and outlets. Silt fence should be installed along the contour to minimize channeling of runoff. They may also be placed perpendicular to prevailing winds at staggered intervals to address wind erosion. The same applications apply to S-Fence.
Limitations · Do not install silt fences along areas where rocks or other hard surfaces will prevent uniformly anchoring the fence posts and entrenching the filter fabric. Improper installation prevents proper function.
Performance and Longevity
Studies have approximated the following effectiveness ranges for silt fences constructed of filter fabric that are properly installed and well maintained:
Removal rates are highly dependent on local conditions and installation.
Silt fence in the LANL area will typically experience the onset of degradation due to UV exposure over a period of 6 to 12 months and will need to be maintained or repaired due to damage from wind and runoff.
S-Fence can also be used as a perimeter control but is made from an HDPE material and has a functional life greater than 4 years. It can also be reused. The product will stand up to winds and UV exposure and can be recycled at the end of its life.
Performance |
Poor or N/A |
Good |
Excellent |
Erosion Prevention |
x |
|
|
Sediment Control |
|
|
x |
Runoff Control |
|
x |
|
Good Housekeeping |
x |
|
|
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Silt Fence |
x |
|
|
|
S-fence |
x |
|
|
x |
Design and Construction Guidance
Materials Silt Fence
Table 1. Minimum requirements for silt fence fabric
Physical property |
Requirements |
Filtering efficiency |
75%-85% (minimum): highly dependent on local conditions |
Tensile strength at 20% (maximum) Elongation |
Standard strength: 30 lb/linear inch (minimum) Extra strength: 50 lb/linear inch (minimum) |
Ultraviolet radiation |
90% (minimum) |
Slurry flow rate |
0.3 gal/ft2/min (minimum) |
S- Fence Product Characteristics
Installation
Inspection and Maintenance
What not to do…
Silt fence should be properly entrenched for proper operation.
20
22
Fiber Rolls
Description Fiber rolls are tube-shaped erosion-control devices filled with straw, flax, rice, coconut fiber material, gravel, or composted material. Common types of this BMP include: straw wattles, coir logs, compost socks, gravel bags, and Terra-Tubes®. Straw wattles are wrapped with UV-degradable polypropylene netting for longevity or with 100% biodegradable materials like burlap, jute, or coir. Coir logs are very similar to straw fiber rolls but are comprised of long lasting coconut fiber. They are also resistant to being consumed by wildlife. Compost socks and gravel bags are three dimensional tubular devices comprised of woven mesh fabric or other similar material and filled with gravel, rock or compost material. Terra-Tubes® are similar to fiber rolls except they are treated with special polymers that react (flocculate) with suspended soil particles, increasing the ability of the suspended solids to settle.
These devices can be used to break up a slope length, reducing the effects of runoff on long or steep slopes. They also help reduce sediment loads to receiving waters by filtering runoff or capturing sediments. Fiber roll BMPs can be used as check structures to reduce runoff velocity and can be placed around storm drain inlets for velocity and sediment control.
Applications · Along the toe, top, face, and at-grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow.
Limitations · They have a limited sediment capture zone.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Straw, Coir logs |
x |
x |
|
|
compost socks |
x |
|
|
x |
gravel bags/snakes |
x |
|
|
x |
Design Criteria and Construction Specifications
Materials
Installation.
Inspection and Maintenance
What not to do…
A rill is forming under the fiber roll. The rill should be filled in. The fiber roll should be properly entrenched into the soil so that water velocity is decreased and water is forced to pool behind to promote sedimentation and flow over the fiber roll.
25
26
Triangular Silt Dike
Description A Triangular Silt Dike (TSD) is a prefabricated triangular shaped piece of foam encased in filter fabric with built in aprons on both sides of the foam body. It is typically used as a temporary control to help reduce the velocity of storm water in a channel or swale or as a perimeter sediment control. A TSD can also be used as a diversion berm to divert storm water around a site or direct the storm water within a site. TSDs can withstand light vehicle traffic.
Applications · Use in channels and swales as a temporary check dam.
Limitations · Ends of TSD sections must be tightly joined to prevent storm water from bypassing the control.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Triangular Silt Dike |
x |
x |
|
x |
Design Criteria and Construction Specifications
Locate TSD as you would other similarly used BMPs.
Inspection and Maintenance
What not to do…
Note that the Triangular Silt Dike sections are not properly joined together and that cinder blocks have been utilized to fill the gap. Sediment accumulations need to be removed from the Triangular Silt Dike.
Construction Entrance/Exit
Description A temporary construction entrance/exit is an area with a singular or series of controls established to manage and reduce off-site tracking of sediment from equipment and vehicles. It reduces the sediment that collects on vehicle tires and minimizes off-site tracking of sediment.
Applications · Locations where mud tracking is a problem during wet weather or where dust is a problem during dry weather.
Limitations · May require replacement of rock during project.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Gravel/Rock |
x |
|
|
|
Grizzly Tracker® |
|
x |
|
x |
Design Criteria and Construction Specifications
Rock entrance
Grizzly Tracker® or similar
Wheel Wash Stations
Inspection and Maintenance
What not to do…
Failure to install a construction entrance has lead to sediment transport offsite.
TEMPORARY GRAVEL CONSTRUCCTTIIOON
Brush Barrier
Description Branches, limbs, and brush are piled at the downhill edge of the site to provide minor runoff pooling to reduce offsite sediment transport.
Applications · Place below the toe of exposed and erodible slopes and at low points of site perimeter.
Limitations · Adequate brush may not be readily available.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
brush barrier |
x |
x |
|
|
Design Criteria and Construction Specifications
Inspection and Maintenance
What not to do…
Notice how the down slope perimeter is unprotected with minimal brush, insufficient for adequate sediment control.
|
Storm Drain Inlet Protection
|
Description The purpose of inlet protection is to filter sediment while still allowing storm water to drain to the inlet or to create ponding around an inlet to allow transported sediment to settle out. These measures are temporary and are implemented before a site is disturbed.
Applications Where sediment laden surface runoff may enter an inlet.
Limitations · Typically requires additional upstream controls for optimal performance.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Block and gravel |
x |
|
|
|
Gravel bags, prefabricated inserts, pop ups, and inlet filters |
x |
|
|
x |
Design Criteria and Construction Specifications
Inspection and Maintenance
What not to do…
Remove sediment and debris in a timely manner from storm drains.
NOTES:
Berms and Channels
Description Berms and channels are most often used to prevent run-on from eroding an exposed or disturbed area, and to divert sediment-laden runoff to a sediment trap, sediment basin or other suitable, stabilized discharge outlet. When used as a temporary control, berms are most often constructed from compacted soil or loose gravel, stone, or crushed rock. Berms may serve as a permanent structural control
when constructed from asphalt, concrete, or other similar material. Channels can be incorporated into a berm design or function as a stand-alone BMP, and are typically constructed from compacted soil or lined with a suitable material.
Applications Effective in diverting run-on away from unprotected areas and reducing flow velocities; effective to retain small amounts of runoff and sediment onsite.
Limitations · A berm with a height of over 2 feet or located in an area where failure of the berm would result in damage to facilities, the environment or other safety issues requires an engineered design.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Earth and base course |
x |
x |
|
|
Asphalt and concrete |
|
|
x |
|
Prefabricated channels and culverts |
x |
x |
x |
x |
Prefabricated barriers |
x |
|
|
x |
Design and Construction Guidance
Inspection and Maintenance
What not to do…
Berm was not well stabilized and could not stand up to run-on flows. Berms and swales should be designed and constructed to handle site specific run-on or run- off flows.
EARTH BERM
Check Dams
Description A check dam is a small dam constructed across a channel, drainage ditch or other area of concentrated flow. Check dams reduce erosion and promote sedimentation by reducing runoff flow velocity and encouraging sediment to settle
out. Check dams are usually constructed of rock, gravel bags, sandbags or other proprietary products and may either be a temporary or permanent structural control.
Applications · Use to minimize down cutting in channels, retain sediment, and reduce velocity.
Limitations · A check dam with a height of over 2 feet or located in an area where failure of the check dam would result in damage to facilities, the environment or other safety issues requires an engineered design.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Rock, logs, juniper bales |
|
x |
x |
|
Gravel bags, Triangular Silt Dike |
x |
|
|
x |
Design and Construction Guidance
Installation:
Inspection and Maintenance
What not to do…
Silt fence cannot be used as a check structure and is not designed for concentrated flow.
Notice how runoff bypassed the check structures. Channel banks
must be sufficient to withstand flows and the dam center must be lower to allow flow over the check dam.
Waterbars and Runouts
Description Features that are used on sloping roads or other linear projects to reduce flow length and to direct runoff from a disturbed area into stabilized areas.
Waterbars are constructed at an angle across the road or disturbed area to prevent water from running a long distance and causing erosion, and to direct runoff into stabilized areas.
Runouts or Turnouts are breaks in a roadside ditch to allow water to exit the ditch and discharge into a stabilized area. This reduces erosion potential and sediment accumulation in the ditch.
Applications Use on dirt or gravel roads, or other longer disturbed areas with a slope, to prevent rills from forming.
Limitations May require rebuilding after large storms or if driven over while soil is saturated.
Performance and Longevity
Performance |
Poor or N/A |
Good |
Excellent |
Erosion Prevention |
|
|
x |
Sediment Control |
x |
|
|
Runoff Control |
|
|
x |
Good Housekeeping |
x |
|
|
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
waterbars and turnouts |
|
x |
|
|
Design and Construction Guidance
Spacing between waterbars and runouts should be based upon site conditions and surface material. General spacing guideline is as follows:
Slope |
Distance between waterbars or runouts |
3% |
200’ |
5-10% |
100’ |
>10% |
50’ |
Inspection and Maintenance
What not to do…
Notice how waterbars are ineffective in diverting and reducing erosive velocity of water. Loose uncompacted soil was used and waterbars were not installed at an approximate 30 degree angle to the road. Water jumped the bars and was not diverted.
Terracing
Description Gradient Terracing is a term used to describe a ridge and channel arrangement constructed across the face of a slope at regular intervals. This break in grade
shortens slope lengths. Each “step” catches material which sloughs from above, and provides a level site where vegetation can become established. Storm water runoff is captured and redirected to a stable outlet. Terracing slopes reduces erosion by decreasing runoff velocities, trapping sediment, increasing water infiltration and promoting vegetative cover.
Applications · Gradient terracing is useful on longer, steeper slopes that have been cleared and are prone to erosion problems.
Limitations · Terracing is not suitable for use on sandy or thin cover soils, or on
excessively steep slopes, and may cause sloughing if too much water
infiltrates the soil.
|
Performance and Longevity
Terraces are generally meant to be permanent, though they can be used in soil staging piles as well.
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
terracing |
x |
x |
|
|
Design and Construction Guidance
Terrace spacing
Average slope |
Horizontal spacing |
Vertical spacing |
2% |
125 ft |
2.5 ft |
6% |
60 ft |
3.5 ft |
10% |
45 ft |
4.5 ft |
14% |
40 ft |
5.5 ft |
Inspection and Maintenance
What not to do…
Water must run along the contour and not jump the terraces.
Surface Roughening
Description The use of mechanized equipment to provide a rough texture to soil surfaces.
Applications Used on bare soil surfaces on a slope. Surface roughening or scarification is a technique used for creating unevenness on bare soil to help prevent slope erosion and formation of rills.
Limitations Does not permanently stabilize area.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Surface roughening |
x |
|
|
|
Design and Construction Guidance
Inspection and Maintenance
What not to do…
Note that the exposed slope was graded with no tracking. This allowed storm water runoff to concentrate and form rills in the soil.
Note that the slope was track-walked in the wrong direction. This will cause rills to
form as water will be allowed to follow the grooves in the soil and gain velocity causing erosion. Track walking with machinery up and down the slope creates grooves that will catch seed and fertilizer and will promote mulch cover to stay on the slope. It will also slow water velocity and reduce runoff and erosion.
Sediment Traps
Description Sediment traps are typically excavated depressions or naturally low areas with earthen embankments, or other similar structures, surrounding all or a portion of the trap footprint. They are used to detain storm water runoff to facilitate the settling of suspended sediment prior to release of the runoff. Sediment is
deposited and retained in an area of specified size identified as a settling zone. The amount of sediment retained, as well as the particle size of the retained sediment, is dependent upon soil characteristics and runoff detention time. Traps also help to reduce runoff velocity through detention, and runoff is generally released from a sediment trap via a spillway that functions similar to a weir and through infiltration into the soil. Sediment traps are most commonly used as temporary BMPs.
Sediment traps are used to detain storm water runoff to facilitate the settling of suspended sediment and to release it at a reduced rate through a controlled outlet structure. The ponding of storm water allows sediment to drop out.
Sediment accumulations must be removed periodically. Sediment traps are typically smaller in size than basins and do not have pipe outlets.
Applications · At locations where runoff velocity or sediment deposition is a concern.
Limitations · A single sediment trap should only be used for small drainage areas.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Sediment trap |
x |
|
|
|
Design and Construction Criteria
Inspection and Maintenance
What not to do…
There is no defined/armored pathway for water to flow in and out of the pond.
Storm Water Detention Basins
Description Storm water detention basins are typically excavated depressions or naturally low areas with earthen embankments, or other similar structures, surrounding all or a portion of the basin footprint. They may also be underground systems located
beneath asphalt or concrete surfaces. Underground systems can be comprised of concrete, corrugated metal pipe, or high density polyethylene material in various geometric configurations.
Detention basins are used to detain storm water runoff to facilitate the settling of suspended sediment and to release runoff at a reduced rate through a controlled outlet structure. The ponding of storm water allows sediment to drop out.
Sediment accumulations must be removed periodically.
Applications · At locations where runoff velocity or sediment deposition is a concern.
Limitations · Required basin size is highly dependent upon the ground cover and associated runoff characteristics of the surrounding drainage area. If areas surrounding the basin are developed after the basin is constructed the basin may not be adequate in size to handle increased flows.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
detention basin |
|
x |
x |
|
Design and Construction Criteria
Inspection and Maintenance
What not to do…
Embankments of pond should be stabilized following initial grading of pond.
Standpipe overflow height is higher in elevation than the basin spillway.
|
Revegetation
|
Description Revegetation is the establishment of short-term or long-term vegetative cover, through seeding, on disturbed surfaces or other areas that pose a high risk of erosion. Seeding can provide temporary or permanent stabilization with reduced
erosion, runoff, and sediment transport. Temporary seeding can be used on any temporary earthen structure, construction sites, topsoil stockpiles, etc. Typical areas appropriate for permanent seeding include denuded areas where long-term vegetative cover is desired, buffer areas, steep slopes, stream banks, and areas where soils are unstable.
Applications · Temporary or permanent stabilization at construction sites, topsoil stockpiles, etc.
Limitations · Establishment of vegetation can take one or more growing seasons and is dependent upon growing conditions (temperature, rainfall, soils, etc.).
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Revegetation |
|
x |
|
|
Design Criteria and Construction Specifications
Design Criteria: Use LANL Master Specification 32 9219 for detailed guidance on seedbed preparation, applicable seed mixes, seeding operations, application rates, and mulch cover products. (http://engstandards.lanl.gov/specs/32_9219R3.doc)
Inspection and Maintenance
ECB and Hydromulch Usage Table
|
slopes steeper than 1:1 |
slopes flatter than 1:1 |
slopes flatter than 2:1 |
slopes flatter than 3:1 |
channels |
Permanent blankets (TRM) |
x |
x |
x |
x |
x |
BFM, FGM hydromulch |
x |
x |
x |
x |
|
Wood fiber hydromulch, compost mulch |
|
|
x |
x |
|
Straw/coir ECBs |
|
|
X |
x |
|
Coir ECBs |
|
x |
X |
X |
|
Visual Key for Proper Application (Flexterra-FGM shown)
Proper Application: 3,000 lb/acre – 4.1 mm thick
Improper Application (thin)
What not to do…
Properly prepare seed bed and ensure mulch or blanketing is installed correctly in order to promote vegetation growth and control erosion.
Temporary Stabilization
Description Temporary stabilization is used for short-term stabilization; when it is known that the area will be disturbed again or when stabilization methods such as seeding are out
of season. The use of rock or recycled wood chip mulch can break up raindrop impact. Hydromulch can be used without seed to provide short-term erosion protection. Dust control additives such as gorilla snot bind the clay particles to provide short-term erosion protection.
Applications · Efficient method of providing immediate, temporary erosion control.
Limitations · Not a permanent control; re-application may be required throughout the season to achieve effective erosion control.
Performance and Longevity
Performance is not as good as permanent stabilization for erosion control; temporary stabilization generally only lasts for a season. Rock and wood mulch last longer but should not be used alone as permanent stabilization.
Performance |
Poor |
Good |
Excellent |
Erosion Prevention |
|
|
x |
Sediment Control |
|
x |
|
Runoff Control |
x |
|
|
Good Housekeeping |
x |
|
|
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Revegetation with Annuals/cover crops |
x |
|
|
|
Mulch |
x |
x |
|
|
Base course |
x |
x |
|
x |
Design Criteria and Construction Specifications
Inspection and Maintenance
What not to do…
Base course should not be used for stabilization in areas of high flow.
Hydromulch should not be applied too lightly or in areas of high flow.
Rolled Erosion Control Products
Combinations and Alternatives
Turf reinforcement mats (TRMs) may be used in conjunction with temporary or permanent sediment and erosion control BMPs to promote vegetation growth. Areas where TRMs are applied should be seeded prior to installation.
Erosion Control Blankets (ECBs) may be used in conjunction with temporary or permanent sediment and erosion control BMPs to promote vegetation growth. Areas where ECBs are applied should be seeded prior to installation.
Description Turf reinforcement mats are a long term non-degradable rolled erosion control product (RECP) comprised of UV stabilized, non-degradable, synthetic fibers or nettings. TRMs are especially useful in areas such as channels that receive higher velocity flows and on slopes requiring immediate permanent soft stabilization.
TRMs can enhance the natural ability of vegetation to protect soil from erosion.
Erosion control blankets are generally a machine produced mat of organic, biodegradable mulch such as straw, curled wood fiber (excelsior), coconut fiber or a combination thereof, evenly distributed on or between photodegradable polypropylene or biodegradable natural fiber netting. ECBs are used to temporarily stabilize and protect disturbed soil from raindrop impact and surface erosion, to increase infiltration, decrease compaction and soil crusting, and to conserve soil moisture. Mulching with erosion control blankets will increase the germination rates for grasses and legumes and promote vegetation establishment. Erosion control blankets also protect seeds from predators; reduce desiccation and evaporation by insulating the soil and seed environment.
Applications TRMs:
Limitations · The slopes must be uniform and relatively smooth before installation to ensure complete contact with the soil.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
TRM |
|
|
x |
|
Design Criteria and Construction Specifications
Site preparation is essential to ensure that RECPs perform as intended and remain in close contact with the soil. Ensure soil amendments are applied as necessary and seed according to LANL Master Specifications Section 32 9219 Seeding. Choose the appropriate turf reinforcement mat for a channel based on the calculated shear stress and water velocities.
Anchoring:
Installation of TRM or ECB on Slopes:
Installation of TRM in channels:
Inspection and Maintenance
What not to do…
TRM installation was not continued along swale where water flow is concentrated, causing erosion.
Properly anchor blanketing on a properly prepared surface.
Dust Suppression
Description Dust control measures are implemented to prevent the soil from leaving the site. Dust control practices include minimization of soil disturbance, water application, mulching, establishing vegetation, and using soil stabilizers or tackifiers.
Applications Apply dust suppression techniques on any site subject to wind erosion and off- site tracking, especially at construction sites and on roads.
Limitations Some temporary dust controls must be reapplied and/or maintained frequently.
Performance and Longevity
Design Criteria and Construction Specifications
Performance |
Poor or N/A |
Good |
Excellent |
Erosion Prevention |
|
|
x |
Sediment Control |
|
|
x |
Runoff Control |
x |
|
|
Good Housekeeping |
x |
|
|
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
water and soil stabilizers |
x |
|
|
|
Inspection and Maintenance
What not to do…
Dust control was not applied sufficiently.
Gabions
Description A gabion is wire enclosed riprap that forms a pervious structure designed to stabilize and protect channels and slopes subject to erosion. By trapping sediment between the stones, gabions also facilitate vegetative growth. The
traditional gabion is a rectangular basket used as a building block for retaining walls and grade control structures. Gabion mattresses, which are not as thick as traditional gabions, are used to line storm drain outlets and channel side slopes and bottoms. The wire used in gabion construction is typically double-twist, hexagonal mesh or welded wire.
Applications In channels for permanent stabilization.
Limitations · Proper design is essential.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Gabion |
|
|
x |
|
Design Criteria and Construction Specifications
Gabion installation should be designed and specified by qualified personnel in accordance with engineering specifications. Installation shall be completed in accordance with the design requirements and manufacturers’ standards and specifications. Additional general information on gabion installation follows:
Inspection and Maintenance
What not to do…
Obstructions not removed from channel before gabion was installed. No filter fabric under the gabions. Scour under the gabions.
Riprap
Description Riprap is a permanent, erosion-resistant layer made of stones. It is intended to protect soil from erosion in areas of concentrated runoff. Riprap generally consists of crushed rock and for added effectiveness may be placed on filter
fabric on a prepared surface. The individual stones are typically angular in shape and well graded to promote interlocking.
Applications · Riprap is effective in protecting culvert inlets and outlets and preventing scouring and undercutting.
Limitations · Proper design and stone selection for expected flow velocity is essential.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Riprap |
|
x |
|
|
Design Criteria and Construction Specifications
Inspection and Maintenance
What not to do…
Properly installed riprap at culvert outlet will control erosion.
Permanent Capping
Description Permanent capping can be achieved using asphalt, concrete, geotextile, clay or soil with vegetative cover. Permanent caps are used when no other alternative
is available to prevent pollutants at a site from leaving. Permanent capping is used to isolate areas of potential soil contamination from storm water. Used when no infiltration or erosion is allowed.
Applications Permanent capping is used when no other alternative is available to prevent pollutants at a site from leaving.
Limitations Expensive engineered control.
|
Performance and Longevity
Longevity |
Temporary (must be removed) |
Long term (may need maintenance) |
Permanent |
Re-useable |
Permanent capping |
|
|
x |
|
Design Criteria and Construction Specifications
Permanent Caps will be designed and inspected by an engineer at the time of installation.
Materials:
Installation:
Inspection and Maintenance
Copyright Soilworks, LLC 2003-. All Rights Reserved. Soilworks®, Soiltac®,
Gorilla-Snot®, and Durasoil® are registered trademarks of Soilworks, LLC.
Copyright Soilworks, LLC 2003-. All Rights Reserved. Soilworks®, Soiltac®,
Gorilla-Snot®, and Durasoil® are registered trademarks of Soilworks, LLC.