ASTM D6460-99
(Test Method)Standard Test Method for Determination of Erosion Control Blanket (ECB) Performance in Protecting Earthen Channels from Stormwater-Induced Erosion
Standard Test Method for Determination of Erosion Control Blanket (ECB) Performance in Protecting Earthen Channels from Stormwater-Induced Erosion
SCOPE
1.1 This test method covers the guidelines, requirements and procedures for evaluating the ability of Erosion Control Blankets (ECBs) to protect earthen channels from stormwater-induced erosion. Critical elements of this protection are the ability of the ECB to:
1.1.1 Neutralize and absorb the hydraulic force of stormwater, thereby reducing soil particle loosening through "scour" mechanisms, and;
1.1.2 Slow runoff and encourage sedimentation, thereby reducing soil particle transport downstream;
1.1.3 Absorb shear forces of overland flow; and,
1.1.4 Trap soil particles beneath.
1.2 This test method utilizes full-scale testing procedures, rather than reduced-scale (bench-scale) simulation, and is patterned after conditions typically found on construction sites at the conclusion of earthwork operations, but prior to the start of revegetation work. Therefore this considers only unvegetated conditions.
Note 1--Future revisions may consider partial or fully vegetated conditions.
1.3 This test method provides a comparative evaluation of an ECB to base line bare soil conditions under controlled and documented conditions.
1.4 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are provided for information purposes only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Also, the user must comply with prevalent regulatory codes, such as OSHA (Occupational Health and Safety Administration) guidelines, while using the test method.
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Designation: D 6460 – 99
Standard Test Method for
Determination of Erosion Control Blanket (ECB)
Performance in Protecting Earthen Channels from
Stormwater-Induced Erosion
This standard is issued under the fixed designation D 6460; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope C 136 Test Method for Sieve Analysis of Fine and Course
Aggregates
1.1 This test method covers the guidelines, requirements
D 422 Test Method for Particle-Size Analysis of Soils
and procedures for evaluating the ability of Erosion Control
D 698 Test Method for Laboratory Characteristics of Soil
Blankets (ECBs) to protect earthen channels from stormwater-
Using Standard Effort
induced erosion. Critical elements of this protection are the
D 2974 Test Methods for Moisture, Ash, and Organic Mat-
ability of the ECB to:
ter of Peat and Other Organic Soils
1.1.1 Neutralize and absorb the hydraulic force of stormwa-
D 4318 Test Method for Liquid Limit, Plastic Limit, and
ter, thereby reducing soil particle loosening through “scour”
Plasticity Index of Soils
mechanisms, and;
1.1.2 Slow runoff and encourage sedimentation, thereby
3. Terminology
reducing soil particle transport downstream;
3.1 Definitions of Terms Specific to This Standard:
1.1.3 Absorb shear forces of overland flow; and,
3.1.1 erosion control blanket (ECB), n—a degradable ma-
1.1.4 Trap soil particles beneath.
terial, composed primarily of processed natural organic mate-
1.2 This test method utilizes full-scale testing procedures,
rials, manufactured or fabricated into rolls designed to reduce
rather than reduced-scale (bench-scale) simulation, and is
soil erosion and assist in the growth, establishment and
patterned after conditions typically found on construction sites
protection of vegetation.
at the conclusion of earthwork operations, but prior to the start
3.1.2 erosion control net (ECN), n—a planar woven natural
of revegetation work. Therefore this considers only unveg-
fiber or extruded synthetic mesh used as a component in the
etated conditions.
manufacture of ECBs.
NOTE 1—Future revisions may consider partial or fully vegetated
3.1.3 index test, n—a test procedure which may contain a
conditions.
known bias, but which may be used to establish an order for a
1.3 This test method provides a comparative evaluation of
set of specimens with respect to the property of interest.
an ECB to base line bare soil conditions under controlled and
3.1.4 lot, n—a unit of production, or a group of other units
documented conditions.
or packages, taken for sampling or statistical examination,
1.4 The values stated in SI units are to be regarded as
having one or more common properties and being readily
standard. The inch-pound units given in parentheses are
separable from other similar units.
provided for information purposes only.
3.1.5 natural, n—a class name of various fibers of animal,
1.5 This standard does not purport to address all of the
mineral or vegetable origin.
safety concerns, if any, associated with its use. It is the
3.1.6 open weave textile (OWT), n—a temporary degradable
responsibility of the user of this standard to establish appro-
ECB composed of natural or polymer yarns woven into a
priate safety and health practices and determine the applica-
matrix used to provide erosion control and facilitate vegetation
bility of regulatory limitations prior to use. Also, the user must
establishment.
comply with prevalent regulatory codes, such as OSHA (Oc-
3.1.7 polymer, n—a chemical compound or mixture of
cupational Health and Safety Administration) guidelines, while
compounds formed by polymerization and consisting essen-
using the test method.
tially of repeating molecular structural units.
3.1.8 sample, n—a portion of material which is taken for
2. Referenced Documents
testing or documentation and used in the laboratory as a source
2.1 ASTM Standards:
of individual specimens.
This Test Method is under the jurisdiction of ASTM Committee D-18 on Soil
and Rock; Subcommittee D 18.25 on Erosion and Sediment Control Technology; Annual Book of ASTM Standards, Vol 04.02.
and is the direct responsibility of Section .02 on Erosion Control Blankets (ECBs). Annual Book of ASTM Standards, Vol 04.08.
Current edition approved Oct. 10, 1999. Published January 2000. Annual Book of ASTM Standards, Vol 15.09.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 6460
3.1.9 shear stress, n—the force of flowing water applied to 6. Apparatus
the surface of a channel in Newtons per square metre (pounds
6.1 Water Delivery System—The water delivery system
per square foot); also, commonly referred to as “tractive force”.
shall include pump(s), piping, channels, and water control
3.1.10 temporary degradable , adj—composed of biologi-
structures, as necessary, to achieve the desired hydraulic
cally, photochemically or otherwise degradable materials that
conditions. The water control structures shall regulate the flow
temporarily reduces soil erosion and enhances the establish-
and to direct it into the desired test channel. The water delivery
ment of vegetation.
system shall be constructed such that turbulence at the entrance
to the test channel is minimized. Use of flow straighteners (for
4. Summary of Test Method
example, tube racks or vanes) are recommended to reduce
4.1 The performance of an erosion control blanket in
turbulence and achieve uniform flow conditions. A direct flow
reducing stormwater-induced erosion is determined by subject-
system (that is, controlled flow diverted from a natural water-
ing the material to simulated stormwater flow in a controlled
way) may also be employed for this purpose. For maximum
and documented environment.
test conditions, a total discharge capability of approximately
3 3
4.2 Key elements of the testing process include:
0.9 m /s (30 ft /s) is recommended. The water delivery system
4.2.1 Calibration of the stormwater simulation equipment;
in Fig. 1 shows an example of a closed-loop water delivery
4.2.2 Preparation of the test channel;
system.
4.2.3 Documentation of the ECB to be tested;
6.2 Water Source—Any water source shall be suitable for
4.2.4 Installation of the ECB;
this use provided that it is not sediment laden or contains
4.2.5 Performance of the test;
deleterious materials which could impair the operation of the
4.2.6 Collection of hydraulic, topographical and associated
pumps.
data;
6.3 Total Station System—The total station system is a
4.2.7 Analysis of the resultant data, and;
standard surveying instrument which is capable of measuring
4.2.8 Reporting.
vertical and horizontal angles, and distance, simultaneously to
determine measurement point coordinates (that is, X, Y and Z
5. Significance and Use
axis) and which uses an internal data logger to store this
5.1 This test method evaluates ECBs and their means of information for future use. In lieu of a total station system,
installation to:
manual surveying equipment may be used provided that
5.1.1 Reduce soil loss and sediment concentrations in equivalent accuracy is achievable. Periodic calibration and
stormwater runoff under conditions of varying channel condi-
certification of this equipment shall be performed.
tions and soil type, and; 6.4 Velocity Probe—A propeller-type probe shall be used to
5.1.2 Improve water quality exiting the area disturbed by
identify flow conditions during test operation. In lieu of a
earthwork activity by reducing suspended solids. propeller-type probe, other velocity measurement devices may
5.2 This test method models and examines conditions typi-
be used provided that equivalent accuracy is achievable.
cally found on construction sites involving earthwork activi- Periodic calibration and certification of this equipment shall be
ties, including: highways and roads; airports; residential, com-
performed.
mercial and industrial developments; pipelines, mines, and 6.5 Miscellaneous—Other miscellaneous equipment in-
landfills; golf courses; etc.
cludes: meteorological equipment (wind speed, temperature,
5.3 This test method is a performance test, but can be used precipitation), and cameras or video recorders.
for quality control to determine product conformance to project
7. Procedure
specifications. Caution is advised since information about
between-laboratory precision is incomplete. Unique project- 7.1 Test Channel Preparation:
specific conditions should be taken into consideration. 7.1.1 Construct earthen test channels using conventional
FIG. 1 Typical Closed Looped Water Delivery System
D 6460
earthwork placement techniques. Perform compaction of chan- discharge (Q) using: the weir equation, and; velocity-area
nel bed material to create a geotechnically (structurally) stable equation. Begin calibration of the water delivery system when
subgrade. a steady-state flow is achieved.
7.1.2 Plate the channel surface with a minimum 45- cm (18– 7.2.2 For open-channel water delivery systems, measure the
in.) thick veneer of soil. General soil types to be used for depth of water flowing into the test channel. Measure the
testing shall be loam, clay and sand. The target gradation velocity in the supply channel using the velocity probe in the
curves for the loam and sand soil types are included in Fig. 2 three-point measurement pattern shown in Fig. 5. Base calcu-
and Fig. 3. The target Plastic Indices (PI) for the loam and clay lation of total discharge on the weir equation and the velocity-
soil types shall be approximately 4.5 and 15.0 6 2.0 and 5.0, area equation (see Section 8).
respectively. Place the veneer in 15– cm (6– in.) lifts and 7.3 Pre-Test Documentation:
compact to approximately 90 to 95 % of standard Proctor 7.3.1 Maintain a test folder for each test cycle, including
density in accordance with Test Method D 698. information on:
7.1.3 Excavate the channels to a trapezoidal cross-section 7.3.1.1 Site conditions;
with a 0.61– m (2–ft) bottom width and 2H:1V side slopes. The 7.3.1.2 Geotechnical and soil conditions;
test channels shall be a minimum of 24.4 m (80 ft) in length. 7.3.1.3 Meteorological data;
A bed slope of approximately of 5 and 10 % is necessary to 7.3.1.4 ECB product type, description and installation pro-
achieve the target shear stress. Fig. 4 shows a typical channel cedure, and;
profile and Fig. 5 shows a typical channel cross-section. 7.3.1.5 Photo documentation.
7.1.4 Begin the test reach 6.1 m (20 ft) below the inlet to the 7.3.2 Include the following subjective site information:
channel and extend 12.2 m (40 ft) downstream from that point. general visual conditions of the channel to be tested; general
Establish benchmarks on either side of the channel at each end meteorological information; channel treatment; photographs or
of the test reach and at 1.5– m (5– ft) intermediate intervals videotape, or both, and any supplemental information that is
(nine cross-sections total). not included in the following sections, but is felt to be of
7.1.5 Loosen the soil veneer in the test reach and 1.5 m (5 interest to the test.
ft) upstream and downstream of the test reach to a depth of 7.3.3 Include the following geotechnical and soils informa-
approximately 10 cm (4 in.) using a tiller or other appropriate tion : soil classification [Unified Soil Classification System
tools. Rake the tilled channel smooth with a steel hand rake and (USCS) and USDA classification system.]; standard proctor
compact using a vibratory plate compactor. Repair depressions, moisture-density relationship; “K” factor; and; gradation (in-
voids, soft or uncompacted areas before testing can commence. cluding hydrometer test for the P fraction).
Also, free the channel from obstruction or protrusions, such as 7.3.4 Include the following meteorological information: all
roots, large stones or other foreign material. data from the on-site weather station at the time of the test (that
7.1.6 If the channel has been used previously for a test is, ambient air temperature, wind speed and precipitation).
series, discard the soil carried out of the channel, and obliterate 7.3.5 Include the following product type and description
any rills and gullies. Spread new soil of the same type across information: manufacturer name; product name; description;
the channel and blend (rake or tilled) into the surface. specifications; size, and; a sample of the material, if practical.
7.2 Calibration: 7.4 Test Set-Up
7.2.1 Perform determination of the water delivery system 7.4.1 Install the ECB in the channel after calibration has
FIG. 2 Typical Loam Grain Size Distribution
D 6460
FIG. 3 Typical Sand Grain Size Distribution
FIG. 4 Typical Channel Profile
FIG. 5 Typical Channel Cross-Section
been completed and the test plot has been prepared,. Document diameter steel tip extension (“stinger”) may need to be attached
the installation methodology for the ECB including: orienta- to the base of the surveyor’s rod. Perform rod placement from
tion on the bed and side slopes (longitudinal or lateral); an above channel platform, so that the rodman does not walk
placement (which side faces up); termination details; joint on the ECB. The rodman must use care in positioning the rod,
details, and; anchor type and installation pattern. Place the so that the measurements are indicative of the channel surface.
ECB over the entire length of the test channel and extend it up The rod shall not rest on the ECB above nor penetrate into the
the side slopes to above the maximum anticipated flow depth. channel surface below.
7.4.2 Measure the elevation of the channel surface (that is, 7.4.3 Take photographs or videotape of the lined channel, or
soil, not ECB) with the total station equipment using the both prior to testing.
reference benchmarks and a stringline between opposing 7.5 Test Operation and Data Collection:
benchmarks,. Take elevation measurements for each test cross- 7.5.1 Include the following test data: operator name and
section (nine total) at the locations shown in Fig. 5. To allow title; time flow began; time flow stopped; time runoff stopped;
measurement of the channel surface, a 0.6– cm (0.25– in.) flow depths, and; measured velocities.
D 6460
7.5.2 Make water surface elevation measurements at the
A , A 5 flow area, m (@ B 5 1.83m, SS 5 2H:1V ⇒
1 3
centerline point of each test cross-section using the total station
0.45y + y ), a
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