manual presentation for public meeting - npdes ti

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Presents Revisions to

The Manual for Erosion and Sediment Control

in Georgia

Effective January 1, 2014

The Manual for Erosion and Sediment Control In Georgia (Manual)

“The Green Book”

•  The Manual Contains standards and

specifications that are followed and practiced in the State of Georgia.

•  Chapter 6 focuses on specifications for planning, design and installation of E&S control measures.

Setting BMP Methods and Standards for Inclusion into the Manual

The Technical Advisory Committee (TAC) Members of the TAC were selected by GSWCC Board based on the individuals: • Experience in erosion and sediment control • Certifications held (i.e. E&SC certification, PE, CPESC)

• Area of expertise (i.e. hydrology, design, etc.)

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The TAC was responsible for: • Selecting appropriate BMP tests and test methods to be considered for approval by the GSWCC Board. • Establishing procedures and criteria for accepting new products and practices into the Manual. • Provide recommendations to GSWCC regarding other revisions to the Manual.

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TAC members include: Joshua Escue Dr. Britt Faucette, CPESC, LEED (Chair) Adena Fullard, PE, CPSWQ Reece Parker, RLA, ASLA, CLARB, LEED Jim Sloan CPESC, CPSWQ Brian Watson, PE, PH

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Advisors to the TAC include: Davie Biagi, Registered Architect, GA DOT Diane Guthrie, PE, NRCS Marc Mastronardi, CPESC, CPSWQ, GA DOT Dewey Richardson, GA EPD


Summary of Changes

Chapter 1 - The Erosion and Sedimentation Act of 1975 •  Minor revisions were made to content •  Existing pictures were replaced with new ones Chapter 2 – Sediment and Erosion Control Processes, Principles and Practices •  Minor revisions were made to content •  Updated to include new Best Management Practices •  Existing pictures were replaced with new ones

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Chapter 3 - Planning and Plans •  Minor revisions were made to existing content •  Added two new sections:

•  “Coordination of Erosion and Sediment Control with Post-Construction Stormwater Management”

•  “Low Impact Development” •  The Erosion and Sedimentation and Pollution

Control Plan has been updated to reflect requirements of O.C.G.A 12-7-1 and NPDES Permits

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Summary of Changes

Chapter 4 - Local Programs: Principles and Processes •  Minor revisions were made to existing content

Chapter 5 – Sources of Assistance and Resource •  Contact information and maps have been updated

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Summary of Changes

Chapter 6 – BMP Standards and Specifications for General Land Disturbing Activities

•  Set performance criteria – “benchmark standards” •  Revised existing BMPs •  Added new BMPs •  Updated technical details

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Summary of Changes

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Chapter 6 (continued) Revised the following BMPs:

•  Matting and Blanket (Mb) –No longer a stand alone BMP, is now a part of the new BMP Slope Stabilization (Ss)

•  Tackifiers and Binders (Tb), changed to Tackifiers (Tac). There are now five types of Tackifiers

•  Polyacrylamide (PAM) – No longer a stand alone BMP, is now a part of Tackifiers (Tac)

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Summary of Changes

Chapter 6 (continued) Revised the following BMPs (continued)

•  Sediment Barriers (Sd1) – There will no longer be Type, A,B,C silt fences.

•  Sediment barriers are now categorized as Type

Sensitive (Sd1- S) and Type Non-Sensitive (Sd1-NS).

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Summary of Changes

Chapter 6 (continued) •  Added performance criteria to:

"   Check Dams (Cd) "   Channel Stabilization (Ch) "   Slope Stabilization (Ss) "   Tackifiers (Tac) "   Sediment Barriers (Sd1) "   Inlet Sediment Traps (Sd2)

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Summary of Changes

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Chapter 6 (continued) "   Added seven new BMPs

(Fl-Co) Flocculants/Coagulants Vegetative (Ss) Slope Stabilization Vegetative (Sk) Filter Surface Skimmer Structural (SpB) Seep Berm Structural (Sd4) Temporary Sediment Trap Structural (Tc) Turbidity Curtain Structural (Tr) Tree Protection Structural

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Summary of Changes

Revised the following BMPs: •  Matting and Blanket (Mb) –No longer a stand alone

BMP,it is now called Slope Stabilization (Ss) •  This BMP now incorporates:

•  Hydraulic erosion control products •  Rolled erosion control products

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Chapter 6 Revised the following BMPs:


Tackifiers and Binders (Tb), changed to Tackifiers (Tac) "   Tackifiers are used as a tie-down for soil,

compost, seed, straw, hay or mulch. Tackifiers hydrate in water and readily blend with other slurry materials to form a homogenous slurry.

"   There are five types of Tackifiers "   These blends take into account

different blends of synthetic and organic polymers.

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Polyacrylamide (PAM) No longer a stand alone BMP

"   This now a part of Tackifiers (Tac) and can be found in Flocculants and Coagulants (Fl-Co) depending on their application.

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Sediment Barriers (Sd1) – There will no longer be Type, A,B,C silt fences.

•  Sediment barriers are now categorized as Type Sensitive (Sd1- S) and Type Non-Sensitive (Sd1-NS). •  Sd1-S is used along state waters and other sensitive areas.

•  The traditionally known silt fence types A,B,C have the potential to now fall into the type-S category depending on testing results.

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"   Sediment Barriers (Sd1) incorporate BMPs other than silt fence for perimeter control.

"   When a Sediment Barrier is used, the product height in inches for each barrier being used must be shown on the plans.

"   Sediment Barriers must be maintained at half their height regardless of size.

"   Sediment Barriers must be maintained to a minimum of 80% of their original height or they have to be replaced.

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Chapter 6 New BMPs:

"  Floating Surface Skimmer (Sk): "   A skimmer drains the water from the top allowing cleaner

less turbid water to discharge from the ponding area. "   Emergency spillway is required

when using a skimmer. "   Can replace the riser pipe as

the principal spillway. "   If a skimmer can not be used

a rationale must be given.

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Chapter 6 New BMPs:

"  Floating Surface Skimmers require the following to be shown on the erosion control plan:

"   Pond, trap or basin size, length in feet (top and bottom) width in feet (top and bottom) and depth

"   Time to Drain (hrs) "   Skimmer Dimensions (orifice and head size in inches)

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Floating “Headworks” Supporting Inlet

Rigid Tube

Flexible Coupling

"  Seep Berm (SpB) •  A seep berm is a linear control

device constructed as a diversion perpendicular to the direction of the runoff to enhance dissipation and infiltration of runoff, while creating multiple sedimentation chambers with the employment of intermediate dikes.

•  To allow the 2 year storm event,24 hour design storm to seep out while allowing larger flows to be diverted to a sediment storage area.

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Chapter 6 New BMPs:

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Seep Berms require the following to be shown on the erosion and sediment control plan:

•  A. Top of Berm Elevation in feet* •  B. Bottom of Berm Elevation* •  C. Top of Berm Width * •  D. Height of the Berm* •  E. Seep Hole Diameter* •  F. Distance from the top of the

berm to the seep to be placed in accordance with the

2yr-24hr storm* •  G. Type of Seep PVC Metal Other (specify) •  H. Spacing of Seep Along the Berm* * shown in feet

Chapter 6 NEW BMPs:

Temporary Sediment Trap (Sd4) •  BMP added to provide sediment storage options for

smaller sites •  All sd4’s to be cleaned out at 1/3rd full •  Provides three options:

1. Temporary Sediment Trap – Overflow 2. Temporary Sediment Trap – Combination Outlet 3. Temporary Sediment Trap

– Rock Outlet

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Chapter 6 NEW BMPs:

1. Temporary Sediment Trap - Overflow (Sd4-A) •  An overflow temporary sediment trap is limited to small areas less than 1 acre, •  The maximum life span of an overflow trap is 6 months. •  Silt fence, straw bale barriers or grass filter strips are used to “polish” the

overflow water as it leaves the sediment trap.

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Chapter 6 NEW BMPs:

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2. Temporary Sediment Trap – Combination outlet (Sd4-B)

•  The combination outlet uses straw bales and silt fence to dewater the sediment trap.

•  Proper installation and staking of the straw bales, and wire backing on the silt fence are required for the materials to resist 1 foot or more of ponded water.

•  The combination straw bale and silt fence outlet is limited to 1 acre total drainage area, and has a life span of less than 1 year.

•  This type of outlet requires frequent maintenance and adjustments to ensure the released stormwater is free from sediment.

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Chapter 6 NEW BMPs:

3. Temporary Sediment Trap – Rock outlet (Sd4-C) •  The rock outlet relies on filtering through layers of aggregate, rock or riprap

material to dewater the sediment trap. •  It is the most sturdy of the sediment trap designs and generally requires less

maintenance. •  It can be used for drainage area up to 5 acres and has a life span of 1 year.

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Chapter 6 NEW BMPs:

Turbidity Curtain (Tc) "   A floating or staked barrier installed within the water. (It may also be

referred to as a floating boom, silt barrier or silt curtain). "   Not to be used as sediment storage. "   Turbidity Curtain is installed to minimize turbidity and silt migration from

work occurring within the water or as a supplement to perimeter control BMPs at the water’s edge.

"   Silt or turbidity is confined to the area within the boundary created by the installation, such that suspended particles drop out of the water column over time.

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Chapter 6 NEW BMPs:

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Chapter 6 (Tc) Turbidity Curtain

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Turbidity Curtain (Tc)

Chapter 6: New Practice Tree Protection (Tr)

Tree Protection (Tr) To protect desirable trees from injury during construction activity. Tree Protection Zones: 1. Measure the diameter of the tree trunk in inches at 4.5 feet from

the ground. This is called the Diameter Breast Height or DBH.

2. Multiply this value by 1.5. This result is the diameter of the root protection zone in feet. This is also considered the critical rooting distance.

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GSWCC selected the most commonly used BMPs to be tested: 1.  Check Dams (Cd) 2.  Sediment Barriers (Sd1) 3.  Inlet Sediment Traps (Sd2)

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BMP TESTING

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Through the bid process GSWCC selected TRI Environmental, Inc. to conduct testing for sediment barriers

and check dams, then later for inlet sediment traps

(TRI) is an independent, third party, geosynthetics firm providing geosynthetics testing and research services.

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BMP TESTING

BMP TESTING

The testing program is intended to characterize a full-scale, installed performance of each BMP.

Test results will set a “benchmark” standard for all practices and products.

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BMP TESTING

TRI randomly selected products found on the GA DOT’s Qualified Products List (QPL) and GSWCC’s Approved Products List (APL)

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Testing –Check Dams (Cd) •  Trapezoidal shaped flume with a 2 ft wide bottom and 2:1 side slopes and a 5% bed slope. •  The test channel is 60 ft long: 40 ft test section + 10ft

upstream and a 10 ft downstream transition sections. •  Concentrated flow produced by opening a valve to allow

gravity flow from an adjacent pond. •  Each test is run at a single predetermined flow rate for 30

minutes.

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TESTING Check Dams (Cd)

•  Flow is metered into the channel via a calibrated sharp-crested weir.

•  9 evenly spaced cross-sections within the test section and 9 evenly spaced measurement points at each cross-section to enable pre and post measurements of the soil surface.

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Rock Check Structure

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ASTM D7208, “Determination of Temporary Ditch Check Performance in Protecting Earthen Channels from

Stormwater-Induced Erosion” (Modified)

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"   Sediment Barriers were tested in accordance with ASTM’s WK11340 (as of Feb 2012) except the slope of the test plots was modified to be 3:1, had a 40 ft slope length, and index tests were run on each material.

"   The rainfall sequence for sediment barriers was run according to ASTM D 6459 - 2 in/hr, 4 in/hr, and 6 in/hr each for 20 minutes. The rain water was tested for turbidity.

TESTING Sediment Barriers (Sd1)

Prepared Control Slope

•  The P-Factor was calculated and reported in accordance with ASTM WK 11340.

•  The test soil was classified as a Sandy Clay as shown on the USDA soil triangle.

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Control End-of-Test Slope

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Index tests were run as follows: •  Mass per Unit Area •  Thickness •  Tensile Strength •  Density (or unit weight per length)

•  Permittivity (a.k.a. Water Flow Rate)

•  Apparent Opening Size (AOS)

•  Percent Open Area (POA)

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TESTING Inlet Sediment Traps (Sd2)

•  The large-scale testing reported herein was performed in general accordance with ASTM D 7351 modified to present the flow to an area inlet.

•  For this testing, a simulated area inlet installation comprised of an approximate 24-inch x 24-inch opening simulating a manhole inlet positioned at the center of a containment area was used.

•  The BMP was installed around the opening and exposed to simulated runoff.

Sediment-laden water was piped and discharged into the fully contained area around the inlet opening and allowed to run up to and seep through, over, and/or under an installed inlet sediment trap BMP protecting the inlet.

•  The amount (via water and soil weight) of sediment-laden flow was measured both upstream and downstream of the BMP.

Un-Paved Paved

•  The measurement of sediment that passes through, over, and/or under the BMP compared to the amount in the upstream flow is used to quantify the effectiveness of the BMP in retaining sediments while allowing continued seepage.

•  The measurement of water that passes through, over, and/or under the BMP compared to the amount of the upstream flow is used to quantify the effectiveness of the BMP in allowing continued seepage.

•  A complete test on each installed BMP

with each type of runoff included 3 repeat flows, or events, separated by not less than 4 hours.


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43 Summary of Results


New Products Submittal Procedure

For BMP entry into GSWCC “APL” “The Green Book”

To be considered for product approval, manufacturers must submit the following:

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1. A completed GSWCC Product Approval Application. 2. Product sample, product specifications, product literature, installation references, field performance data, and any other state agency that has testing in progress, tests completed and/or product approval.

Submittal Process (continued) 3.  Certified lab results from a qualified

laboratory capable of performing the required GSWCC tests.

4.  Private label identification: Provide a letter

from the private labeler identifying source and name of material along with a companion letter from the manufacturer. Material properties and identifying names shall be included in the letters of certification.

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Products that meet GSWCC specified benchmarks are not guaranteed to be placed on the

GSWCC Approved Products List. •  Products that are not environmentally

compatible will not be allowed. •  Product information submitted by the

manufacturers to GSWCC will not be considered confidential unless otherwise noted.

•  All products must be approved by the GSWCC Board.

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Recertification of products •  Recertification of products, on a 3 year cycle, will be

required for products to remain on the approved list.

•  Manufacturers will be required to submit a letter certifying that the product is still being manufactured with the same quality and composition as the test material originally submitted for evaluation. The submission of index tests may also be required.

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Recertification of products (continued)

•  If modifications to an approved product have been made, manufacturers must have the current product retested and

results submitted to GSWCC.

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Channel Stabilization (Ch) Products seeking approval for channel stabilization applications must be tested according to ASTM D6460 - “Standard Test Method for Determination of Rolled Erosion Control Product (RECP) Performance in Protecting Earthen Channels from Stormwater-Induced Erosion”.

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Channel Stabilization (Ch) Products will be categorized as followed: Category 1 (0-5 ft/sec) Vegetated Lining with Blankets

Category 2 (5- 10 ft/sec) Vegetated Lining with TRM or Rip Rap Lining

Category 3 (> 10 ft/sec) Concrete Lining

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Check Dams (Cd) Products seeking approval for check dam applications must be tested using ASTM D7208 (Modified), as specified by GSWCC. The check dam must perform better than the unchecked channel 20% of control (i.e. 80% reduction in soil loss), and withstand a flow rate of 2.0cfs.

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Check Dams (Cd) The product shall be tested at 0.5cfs, 1.0cfs and 2.0cfs, using sandy clay soil as shown on the USDA soil triangle.

Please refer to GSWCC Approved Test Method for check dams, for complete testing procedures.

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Inlet Sediment Traps (Sd2) Products seeking approval for inlet sediment trap applications must be tested using ASTM D7351 – Modified (Proposed April 2013), as specified by GSWCC.

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Inlet Sediment Traps (Sd2) Inlet sediment traps shall meet : •  90% soil retention efficiency with a •  minimum seepage efficiency of 65% •  for unpaved areas

•  75% soil retention efficiency with a •  minimum seepage of 85% for paved areas.

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Rolled and Hydraulic Erosion Control Products To be approved as a RECP or HECP the manufacturer must submit independent research data from rainfall simulated slope tests conducted through the National Transportation Product Evaluation Program (NTPEP) using ASTM D6459.

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Rolled and Hydraulic Erosion Control Products

Products shall have a maximum C-factor ASTM D6459 for the following slope grade: Slope (H: V) C-Factor (max.) 3:1 or steeper 0.080


Sediment Barriers (Sd1) GSWCC is incorporating elements from the “Methods” and “Data Analyses” sections of the technical publication titled “Needed Information: Testing, Analyses, and Performance Values for Slope Interruption and Perimeter Control BMPs” authored by Kurt Kelsey, Tony Johnson, and Ryan Varva (IECA 2006) and portions of ASTM D6459 and ASTM WK 11340 (February 2012) to create its own test for sediment barrier (Sd1) products.

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Sediment Barriers (Sd1) Please refer to GSWCC Approved Test Method for sediment barriers for complete testing procedures.

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Each product will be required to perform index testing for quality control purposes.

Sediment Barriers (Sd1) The index testing are as follows: Two Dimensional Products (Geotextile – type), will include, but not limited to: •  Mass /Area Thickness – ASTM D 5261 and ASTM D 5199 •  Tensile Strength – ASTM D 4632 •  Permittivity (flow) – ASTM D 4491 •  Apparent Opening Size – ASTM D 4751 •  Percent Open Area – Light Projection

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Sediment Barriers (Sd1) Three Dimensional Products (Watttle – type), will include, but not limited to: •  Mass/Volume •  Circumference/Perimeter •  Relevant Component Properties, such as but not limited to netting

tensile strength If a product does not meet one of these categories, please contact GSWCC’s Urban Program to discuss what index tests would be required


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Sediment Barriers (Sd1) Products seeking approval must meet a P-factor of 0.030 for sensitive area applications and a P-factor of 0.045 for non sensitive area applications. Sensitive areas can be defined as any area that needs additional protection, these areas include but are not limited to, state waters, wetlands, or any area the design professional designates as sensitive.


Tackifiers (Tac) For general use, the tackifier must meet the specifications in Manual. To be used in other BMP applications such as Slope Stabilization or Channel Stabilization please refer to that BMP testing specification.


GSWCC Urban Lands 706-552-4474

Ben Ruzowicz, Guerry Thomas, Lauren Zdunczyk T. Luke Owen, PG

678-469-5120

It’s Not the Water in Your Life, It’s the LIFE IN YOUR WATER!

manual presentation for public meeting - npdes ti

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