ASTM D6459-99
(Test Method)Standard Test Method for Determination of Erosion Control Blanket (ECB) Performance in Protecting Hillslopes from Rainfall-Induced Erosion
Standard Test Method for Determination of Erosion Control Blanket (ECB) Performance in Protecting Hillslopes from Rainfall-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 hillslopes from rainfall-induced erosion. Critical elements of this protection are the ability of the ECB to:
1.1.1 Absorb the impact force raindrops, thereby reducing soil particle loosening through "splash" mechanisms;
1.1.2 Slow runoff and encourage infiltration, thereby reducing soil particle displacement and transport through "overland flow" mechanisms;
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 baseline 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 values 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 6459 – 99
Standard Test Method for
Determination of Erosion Control Blanket (ECB)
Performance in Protecting Hillslopes from Rainfall-Induced
Erosion
This standard is issued under the fixed designation D 6459; 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 2. Referenced Documents
1.1 This test method covers the guidelines, requirements 2.1 ASTM Standards:
and procedures for evaluating the ability of Erosion Control C 136 Test Method for Sieve Analysis of Fine and Course
Blankets (ECBs) to protect hillslopes from rainfall-induced Aggregates
erosion. Critical elements of this protection are the ability of D 422 Test Method for Particle-Size Analysis of Soils
the ECB to: D 698 Test Method for Laboratory Characteristics of Soil
1.1.1 Absorb the impact force of raindrops, thereby reduc- Using Standard Effort
ing soil particle loosening through “splash” mechanisms; D 2974 Standard Test Methods for Moisture, Ash, and
1.1.2 Slow runoff and encourage infiltration, thereby reduc- Organic Matter of Peat and Other Organic Soils
ing soil particle displacement and transport through “overland D 4318 Standard Test Method for Liquid Limit, Plastic
flow” mechanisms; Limit, and Plasticity Index of Soils
1.1.3 Absorb shear forces of overland flow; and,
3. Terminology
1.1.4 Trap soil particles beneath.
1.2 This test method utilizes full-scale testing procedures, 3.1 Definitions of Terms Specific to This Standard:
3.1.1 erosion control blanket (ECB), n—a degradable ma-
rather than reduced-scale (bench-scale) simulation, and is
patterned after conditions typically found on construction sites terial, composed primarily of processed natural organic mate-
rials, manufactured or fabricated into rolls designed to reduce
at the conclusion of earthwork operations, but prior to the start
of revegetation work. Therefore this considers only unveg- soil erosion and assist in the growth, establishment and
etated conditions. protection of vegetation.
3.1.2 erosion control net (ECN), n—a planar woven natural
NOTE 1—Future revisions may consider partial or fully vegetated
fiber or extruded synthetic mesh used as a component in the
conditions.
manufacture of ECBs.
1.3 This test method provides a comparative evaluation of
3.1.3 index test, n—a test procedure which may contain a
an ECB to baseline bare soil conditions under controlled and
known bias, but which may be used to establish an order for a
documented conditions.
set of specimens with respect to the property of interest.
1.4 The values stated in SI units are to be regarded as
3.1.4 lot, n—a unit of production, or a group of other units
standard. The inch-pound values given in parentheses are
or packages, taken for sampling or statistical examination,
provided for information purposes only.
having one or more common properties and being readily
1.5 This standard does not purport to address all of the
separable from other similar units.
safety concerns, if any, associated with its use. It is the
3.1.5 natural, n—a class name of various fibers of animal,
responsibility of the user of this standard to establish appro-
mineral or vegetable origin.
priate safety and health practices and determine the applica-
3.1.6 openweavetextile(OWT),n—atemporarydegradable
bilityofregulatorylimitationspriortouse. Also, the user must
ECB composed of natural or polymer yarns woven into a
comply with prevalent regulatory codes, such as OSHA (Oc-
matrix used to provide erosion control and facilitate vegetation
cupational Health and SafetyAdministration) guidelines, while
establishment.
using the test method.
This test method is under the jurisdiction of ASTM Committee D-18 on Soil
andRock;SubcommitteeD18.25onErosionandSedimentControlTechnology;and Annual Book of ASTM Standards, Vol 04.02.
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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6459
3.1.7 polymer, n—a chemical compound or mixture of 5.1.1 Reduce soil loss and sediment concentrations in
compounds formed by polymerization and consisting essen- stormwaterrunoffunderconditionsofvaryingrainfallintensity
tially of repeating molecular structural units.
and soil type, and;
3.1.8 sample, n—a portion of material which is taken for
5.1.2 Improve water quality exiting the area disturbed by
testing or documentation and used in the laboratory as a source
earthwork activity by reducing suspended solids.
of individual specimens.
5.2 This test method models and examines conditions typi-
3.1.9 temporary degradable, adj—composed of biologi-
cally found on construction sites involving earthwork activities
cally, photochemically or otherwise degradable materials that
including:highwayandroads;airports;residential,commercial
temporarily reduce soil erosion and enhance the establishment
and industrial developments; pipelines, mines, and landfills;
of vegetation.
golf courses; etc.
5.3 This test method is a performance test, but can be used
4. Summary of Test Method
forqualitycontroltodetermineproductconformancetoproject
4.1 The performance of an erosion control blanket in
specifications. Caution is advised since information about
reducing rainfall-induced erosion is determined by subjecting
between-laboratory precision is incomplete. Unique project-
the material to simulated rainfall in a controlled and docu-
specific conditions should be taken into consideration.
mented environment.
4.2 Key elements of the testing process include:
6. Apparatus
4.2.1 Calibration of the rainfall simulation equipment;
4.2.2 Preparation of the test plot;
6.1 Rainfall Simulators—Rainfall simulators shall include
4.2.3 Documentation of the ECB to be tested;
sprinkler heads, sprinkler risers, valves and pressure gages.
4.2.4 Installation of the ECB;
Thesprinklerheadsshouldbeselectedontheirabilitytomodel
4.2.5 Performance of the test;
natural raindrop size and distribution (no more than 10 %
4.2.6 Collection of runoff and associated sediment yield
greater than 6 mm (0.24 in.) and no more than 10 % smaller
data;
than 1 mm (0.04 in.)). To approximate the kinetic energy of
4.2.7 Analysis of the resultant data, and;
natural rainfall, the sprinkler riser shall be constructed to
4.2.8 Reporting.
position the sprinkler heads to achieve a minimum fall height
(peak vertical trajectory) of 4.3 m (14 ft).Aflow control valve
5. Significance and Use
and a pressure gauge capable of maintaining a uniform
5.1 This test method evaluates ECBs and their means of operating pressure shall be located on each riser. Fig. 1 shows
installation to: an example of a rainfall simulator.
FIG. 1 Typical Rainfall Simulator
D 6459
6.2 Water Source—Any water source shall be suitable for water onto the test plot (“run-on”) occurs. The barrier shall be
this use provided that it does not contain deleterious materials continuous such that joints do not allow outside flow to enter
which could impair the operation of the rainfall simulators. the plot. Commercially available lawn edging is suitable for
6.3 RunoffandSedimentCollectionSystem—Therunoffand this purpose.
sediment collection system includes flashing, collection appa-
7.1.5 Loosen the soil veneer to a depth of approximately 10
ratus and a holding tank. Flashing shall be fabricated to direct cm (4 in.) using a tiller or other appropriate tools. Rake the
runoff from the plot into the collection apparatus. Once the tilled plot smooth with a steel hand rake and lightly compact
runoff is on the flashing, it may be desirable to divert the flow using a turf roller. Repair depressions, voids, soft, or uncom-
to a single collection point. The flashing shall be continuous pactedareasbeforetestingcommences.Also,freetheplotfrom
across the entire bottom edge of the plot. A holding tank(s) obstruction or protrusions, such as roots, large stones, or other
capable of temporarily containing all runoff shall be connected foreign material.
to the collection apparatus. 7.1.6 If the plots have been used for previous test series,
6.4 Miscellaneous—Other miscellaneous equipment in-
discard the soil carried of the plot and obliterate any rills and
cludes: rain gauges (20), pie pans (3), sieve set (standard US gullies. Spread new soil of the same type across the plot and
sieves), evaporating dishes, a drying oven or microwave oven,
blend(rakeortill)intothesurface.Ifthesoillossofthecontrol
balances, meteorological equipment (wind speed, temperature,
plot differs significantly from the base line calibration test
precipitation),asurveyor’srod,samplebottlesandbags,cooler
reevaluate the soil properties.
and camera or video recorder.
7.2 Calibration:
7.2.1 Calibration of the rainfall simulation equipment in-
7. Procedure
cludes:
7.1 Test Plot Preparation:
7.2.1.1 Rainfall intensity;
7.1.1 Construct an earthen embankment using conventional
7.2.1.2 Uniformity of rainfall application across the plot,
earthwork placement techniques. Perform compaction of the
and;
embankment to create a geotechnically (structurally) stable
7.2.1.3 Drop size distribution for each intensity.
embankment with a surface slope of 3H:1V having a slope
7.2.2 To ensure uniform distribution, do not conduct cali-
length of 12 m (40 ft). Fig. 2 shows a typical embankment
bration and testing when the wind velocity is greater than 8
cross-section.
km/h (5 mph).
7.1.2 Plate the top surface of the embarkment with a
7.2.3 At a minimum, conduct calibration annually or fol-
minimum 15 cm (6 in.) thick veneer of soil. General soil types
lowing equipment maintenance work. Conduct one intensity/
to be used for testing shall be loam, clay and sand. The target
uniformity check every 90 days, or after no more than four test
gradation curves for the loam and sand soil types is included in
series, whichever comes first.
Fig. 3 and Fig. 4. The target plastic indices (PI) for the loam
7.2.4 Place sprinkler risers around the perimeter of the test
and clay soil types shall be approximately 4.5 and 15.0 6 2.0
plottoprovideuniformdistribution.Thepreciselocationofthe
and 5.0, respectively. Place the veneer in 15 cm (6 in.) lifts and
risers to provide uniform rainfall distribution will be deter-
compact to approximately 90 to 95 % of standard proctor
mined by the calibration process and the nuances of any given
density in accordance with Test Method D 698.
simulator system (See Fig. 5 for typical sprinkler riser con-
7.1.3 Locate test plots on the embankment using a plot size
figuration.).
of 2.4 m (8 ft) in width (cross-slope) and of 12 m (40 ft) in
7.2.5 Place the rain gages on the plot surface following the
length (downslope). Separate the test plots such that overspray
patternshowninFig.5.Durationofthecalibrationtestshallbe
from the rainfall simulators does not impact adjacent plots.
15 min, recorded to the nearest second. Perform calibrations at
uniform pressure for each intensity.Adjust riser locations until
NOTE 2—The slope width, length and steepness were selected as being
representativeofconditionstypicallyfoundonconstructionsites.Thistest an acceptable uniform rainfall distribution pattern is achieved,
plot configuration was chosen to assure uniformity and consistence of
as defined in Section 8.
testing activities.
7.2.6 Calculate the rainfall intensity uniformity using the
7.1.4 Isolate the top edge and sides of each test plot by a Christiansen uniformity coefficient (see Section 8).
water barrier which forms the boundary of the test plot. Bury 7.2.7 Tomeasuredropsizedistribution,completelyfillthree
the bottom edge of the barrier approximately 10 cm (4 in.) to labeled pie pans with sifted flour, struck off with a ruler to
divert surface flow such that no intrusion of outside surface produce a smooth, uncompacted surface. Locate three supports
FIG. 2 Typical Embankment Cross Section
D 6459
FIG. 3 Typical Loam Grain Size Distribution
FIG. 4 Typical Sand Grain Size Distribution
approximately 20-cm (8- in.) high (for example, 1-gal cans) shakingthestackfor2min.Cullforeignmatterandanydouble
along the vertical centerline of the test plot, and at the pellets from each sieve and record the total weight and pellet
horizontal quarter points. Place the filled pie pans on the count for each size. (1)
supports (horizontal, not parallel to the ground) and cover. At 7.2.8 Repeat the raindrop size calibration procedure (7.2.7)
the desired test intensity, remove the cover briefly so that drops three times for each desired intensity.
impinge on the flour to form pellets. Recover the pans after 7.2.9 Determine raindrop fall height by measuring the
only a few seconds and before the drops start to touch each average height of the raindrop trajectory using a surveyor’s
other. Repeat this procedure at each desired intensity. Air-dry rod. Hold the rod vertically in the spray of a single riser and
the flour pellets for a minimum of 12 h. Screen each sample of measure the wetted height. Repeat the height measurement for
these semi-dry pellets by emptying the entire contents of the each desired intensity.
pan onto a 70 mesh sieve to carefully remove as much loose 7.3 Pre-Test Documentation:
flour as possible. Then transfer the remaining pellets to
evaporating dishes and heat in an oven at approximately 43°C
(110°F) for 2 h. Record the total weight of the hard flour
The boldface numbers given in parentheses refer to a list of references at the
pellets. Sieve the pellets through standard soil sieves by end of the text.
D 6459
FIG. 5 Typical Sprinkler Riser Configuration
7.3.1 Maintain a test folder for each test cycle, including present along the perimeter barrier and be cut to fit, as
information on: site conditions; geotechnical and soil condi- necessary, to cover the plot.
tions; meteorological data; ECB product type, description and 7.4.3 Take photographs or videotapes, or both of the cov-
installation procedure, and; photo documentation. ered plot prior to testing.
7.3.2 Include the following subjective site information: 7.5 Test Operation and Data Collection:
general visual conditions of the plot to be tested; general 7.5.1 Include the following test data: operator name and
meteorological information; plot treatment; photographs o
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