ecmds 5.0 design manual

Design ManualErosion Control Materials Design Software(ECMDS) Version 5.0

Copyright 2011 North American Green, Inc.

Tensar International Corporation |5401 St. Wendel Cynthiana Road |Poseyville, Indiana 47633 | Tel. 800-772-2040 | Direct 812-867-6632 |www.nagreen.com

2Erosion Control Materials Design SoftwareVersion 5.0

Table of Contents1.0 Design Module Overview

1.1 Slope Design Module1.2 Channel Design Module1.3 User Defined Channel Design Module1.4 Spillway Design Module1.5 Outlet Design Module1.6 Drop Structure Design Module1.7 Vegetation Selection Module

2.0 Design Module Methodology2.1 Slope Design Module

2.1.1 Terminology and Definitions2.1.2 Slope Design Methodology

2.2 Channel Design Module2.2.1 Terminology and Definitions2.2.2 Channel Design Methodology2.2.3 User-defined Channel Methodology2.2.4 Channel Methodology using Mattress products

2.3 Spillway Design Module2.3.1 Terminology and Definitions2.3.2 Spillway Design Methodology

2.4 Outlet Design Module2.4.1 Terminology and Definitions2.4.2 Outlet Design Methodology

2.5 Drop Structure Module2.5.1 Terminology and Definitions2.5.2 Drop Structure Methodology

2.6 Vegetation Selection Module2.6.1 Terminology and Definitions

3.0 Appendix3.1 Soil Textural Triangle3.2 C-Factors for Erosion Control Products3.3 Hydraulic Roughness Coefficients for Erosion Control Products3.4 Permissible Shear Stress of Vegetation Based on Plant Height and Density3.5 Permissible Shear Stress of Unvegetated Erosion Control Products3.6 Permissible Shear Stress of Vegetated TRMs3.7 Permissible Shear Stress of Soils3.8 Mattress Unit Thickness Guidelines3.9 Hydraulic Roughness Coefficients for Pipe/ Culvert Outlet Types3.10 Mattress Rock Fill Densities

4.0 References

31.0 Design Module OverviewNorth American Greens Erosion Control Materials Design Software (ECMDS) 5.0 is designed to offerthe most complete resource for analyzing erosion control products and their performance in specificproject parameters. This section will give you a basis for the analytical ability of each design module.For specific design methodology reference section 2.0.

1.1 Slope Design Module

The Slope Design Module of ECMDS 5.0 provides recommendations in the selection ofeffective temporary and/or permanent erosion protection for a uniform slope face underrainfall induced sheet/rill flow conditions. The materials analysis and performance evaluationare conducted using equations and data from the USDAs Revised Universal Soil Loss Equation(RUSLE)13 and the NCHRP Report 224. The stability check for slope protection materials isbased on the materials capability to provide the necessary degree of erosion protectionagainst rainfall induced erosion for a specified time period. The effectiveness of NorthAmerican Green erosion control products have been determined based on 3rd party researchperformed at Texas Transportation Institute, Purdue University, Utah State University, SanDiego State University, and Texas Research International / Environmental.

1.2 Channel Design Module

The Channel Design Module provides recommendations for effective temporary and/orpermanent erosion protection of swales and channels conveying intermittent concentrateduniform water flows. The channel lining analysis and performance evaluations are conductedusing the maximum shear stress (tractive force) method as outlined in the Federal HighwayAdministrations Hydraulic Engineering Circular #151and the USDAs Agricultural Handbook#66720. The effectiveness of North American Green erosion control products have beendetermined based on 3rd party research performed at Colorado State University, TexasTransportation Institute, Utah State University, and Texas Research International /Environmental. The stability check for channel lining materials is based on the productscapability to effectively control soil loss on the channel surface under the calculated shearstresses for a specified flow period.

This section should be used for channel designs when the known values include discharge (Q)and channel dimensions.

1.3 User Defined Channel Design Module

The User Defined Channel Design Module provides recommendations for effective temporaryand/or permanent erosion protection of swales and channels conveying intermittentconcentrated uniform water flows. The channel lining analysis and performance evaluationsare conducted using the maximum shear stress (tractive force) method as outlined in theFederal Highway Administrations HEC #151and the USDAs Agricultural Handbook #66720.The effectiveness of North American Green erosion control products have been determinedbased on 3rd party research performed at Colorado State University, Texas TransportationInstitute, Utah State University, and Texas Research International / Environmental. Thestability check for channel lining materials is based on the products capability to effectivelycontrol soil loss on the channel surface under the calculated shear stresses for a specifiedflow period.

4This section varies from the Channel Design Module based on the input parameters and themethod of calculating the mannings n.This module should be used when the known input parameters are flow depth and velocity.

1.4 Spillway Design Module

The Spillway Design Module provides recommendations for effective temporary and/orpermanent erosion protection of spillways conveying intermittent uniform water flows. Thespillway analysis and performance evaluations are conducted using the maximum shearstress and the mannings n equation. The stability check for spillway materials is based on theproducts capability to effectively control soil loss on the spillway surface under the calculatedshear stresses for a specified flow period.

1.5 Outlet Design Module

The Outlet Design Module provides recommendations for effective temporary and/orpermanent erosion protection of pipe and culvert outlets conveying intermittent water flows.The outlet analysis and performance evaluations are conducted using the maximum shearstress and the mannings n equation, based on full or half flow conditions. The stability checkfor outlet materials is based on the products capability to effectively control soil loss andscour at the outlet structure under the calculated shear stresses for a specified flow period.Protective dimensions for outlet erosion control products are based on standard pipe andscour apron designs relative to outlet sizing.

1.6 Drop Structure Design Module

The Drop Structure Design Module provides recommendations for effective temporaryand/or permanent erosion protection in drop structures conveying intermittent water flows.The drop structure analysis and performance evaluations are conducted using the maximumshear stress and the mannings n equation, based on mannings equations, drop height andbasin length. The stability check for drop structure materials is based on the productscapability to effectively control soil loss and scour at the drop structure under the calculatedshear stresses for a specified flow period.

1.7 Vegetation Selection Module

The Vegetation Selection Module provides recommendations for suitable grasses andlegumes species for erosion control for the continental U.S and parts of Canada. Therecommendations are based on soil type, moisture regime, planned site maintenance, andregional location of the project site. Due to additional factors not considered in this module,this module only provides general recommendations for species types and monoculturalseeding rates. A soil fertility test is recommended before selecting vegetation.

52.0 Design Module Methodology2.1 Slope Design Module

2.1.1 Terminology and Definitions

The Revised Universal Soil Loss Equation accounts for the primary factors affectingsoil erosion by water and is used to predict soil loss within the Slope DesignModule.

RUSLE: The Revised Universal Soil Loss Equation is a mathematical model used todescribe soil erosion processes. The equation was developed by the USDA-NRCSSoil Conservation Service, and is the main methodology for predicting soil erosionfrom rainfall induced runoff.

The RUSLE uses the following factors to calculate the average soil loss from aslope:

R factor: The annual rainfall/runoff factor for a given location through a giventime periodK factor: The slope erodibility factor. A value between 0 and 1 assigned to specificsoil types.LS factor: Slope length and gradient factor, a value affecting the erodibility of theslope face. Longer, steeper slopes are typically more erodible.C factor: Cover factor, a value assigned to a particular type of erosion controlcover based on the products ability to provide cover and erosion protection.Average Soil Loss (A): The resulting value from the RUSLE equation, calculated inuniform inches (cm) (depth of soil loss) for the slope.

In addition, the RUSLE equation can be used more specifically to evaluate theaverage soil loss or maximum soil loss from bare (unprotected slopes) or fromprotected slopes.

ASL (Average Soil Loss)100% of slope

MSL (Maximum Soil Loss)Lower 10% of slope

ASL (Average Soil Loss)100% of slope

MSL (Maximum Soil Loss)Lower 10% of slope

ASLBare: The average soil loss (in or cm) from the bare unprotected slope.ASLMat: The average soil loss (in or cm) from a slope protected with a materialMSLBare: the maximum soil loss (in or cm) from a bare unprotected slope,averaging the soil loss from the lower 10% of the slope.

6MSLMat: the maximum soil loss (in or cm) from a slope protected with a material,averaging the soil loss from the lower 10% of the slope.

Stability of a slope is determined by calculating a:

Safety Factor (SF): A value assigned to determine the stability of slope with orwithout erosion protection. The safety factor is determined by comparing the SoilLoss Tolerance to the MSLBare when looking at unprotected slopes, or the MSLMatwhen analyzing protected slopes.

Soil Loss Tolerance (SLT): The tolerable amount of soil that can be lost underspecified time frames. ECMDS 5.0 will use an SLT of 0.25 inches for temporaryprotection, and an SLT of 0.03 inches for permanent protection. The 0.03 inch SLTis based on the USDAs tolerable average annual soil loss for many different soiltypes. These limits are based on the soils capacity for regeneration.

2.1.2 Slope Design Methodology

The Slope Design Module is based on the methodology established by the USDAsRUSLE.

A = R x K x LS x C x 0.00595 where,

0.00595 = conversion factor for soil loss rate from tons/acre to uniform inches

The RUSLE can also be used to solve for:

ASLBare = R x K x LS x C x 0.00595 where,C = 1.0, or an unprotected state

ASLMat = ASLBare x C where,C = value assigned to a specific cover material, (See appendix 3.2)

MSLBare = ASLBare x 1.7 where,1.7 = factor based on the erodibility of lower 10% of slope

MSLMat = MSLBare x C where,C = value assigned to a specific cover material

Stability is determined from a Safety factor

SF = SLT / MSLMat or BareIf SF > 1.0 = Stable Design,If SF < 1.0 = Unstable Design

72.2 Channel Design Module


The Channel Design Module analysis is conducted using the maximum shear stressmethod outlined in the FHWAs HEC #15 Design for Roadside Channels withFlexible Liners and the USDAs Handbook #667.

Shear Stress: The amount of force developed along the interface of the flowingwater and surface material in the direction of flow. Factors effecting shear stressinclude gravity, water flow along a material and roughness of lining material.

Maximum Permissible Shear Stress: The maximum force along the flowing waterand surface material interface where any further increase in force will causemovement of lining material or allow more than the tolerable amount of soil loss.

Channel designs using the shear stress method are found to be more accuratethan using simple velocity calculations.

Velocity: Rate of water flow typically expressed in feet per second, or the timerate of displacement of a fluid particle from one point to another.

To ultimately evaluate a channel liners stability, a safety factor is calculated.

Channel Liner: A material used to line the channel and offer stabilization for theunderlying soil. Channel liners are classified as rigid (such as concrete) or flexible(such as vegetation, erosion mattings, and rock).

Mannings n: A coefficient for the hydraulic roughness of the surface of a channel(or channel liner). The values for n will vary with depth of water flowing in thechannel.

Safety Factor (SF): A value assigned to determine the stability of a channel. Thesafety factor is determined by comparing the calculated shear stress in thechannel to the maximum permissible shear stress of the channel lining material.

2.2.2 Channel Design Methodology

The Channel Design Module utilizes the mannings n equation and the givenchannel input parameters and discharge rates to back calculate the cross sectionalarea, wetted perimeter and the hydraulic radius of the channel. These values arethen used in the Continuity Equation to calculate the channel velocity.

Mannings n equation:Flow (Q) = 2/13/2 ***486.1 SRA

nwhere,

A = Cross-Sectional AreaR = Hydraulic Radius

8S = Channel Slope or Energy Gradient (averaged under uniform flow conditions)n = hydraulic roughness coefficient of channel liner (See Appendix 3.3)

The Cross sectional area (A):A = AL + AB + AR where,

Area of Left (AL) = * d2 *ZL where,d = depth of channelZL = slope grade of left side slope

Area of Base (AB) = WB * d where,WB = Bottom width of channel

Area of Right (AR) = * d2 *ZR where,ZR = slope grade of right side slope

Wetted Perimeter (P):P = PL + PB + PR where,

Left Perimeter (PL) = d *(ZL +1)0.5Base Perimeter (PB) = WBRight Perimeter (PR) = d *(ZR +1)0.5

Hydraulic Radius (R):R = A / P

Continuity Equation:Velocity (V) = Q / A

Calculated Channel Shear Stress (Td):Td = Y * d * S where,

Y = unit weight of water or (62.4 lbs/ft3)

Channel Liner Safety Factor (SFL):SFL = Tp / Td where,Tp = Permissible shear of channel liner (see Appendix 3.4 , 3.5 or 3.6)

Effective Shear Stress on Liner (Te):Te = Td * (1-Cf) *(ns/n)2 where,

Cf = Cover factor of channel liner (see Appendix 3.2)ns = hydraulic roughness of underlying soil (0.0156 for most soil types)n= hydraulic roughness of channel liner (see Appendix 3.3)

Soil Safety Factor (SFs):SFs = Ta / Te where,Ta = Permissible shear of soil (see Appendix 3.7)

Calculated Channel Shear Stress in Bend Areas (Tdb):Tdb = Kb * Td where,

9Bend coefficient (Kb) = Rc / WB where,Rc = Radius of bend curvatureWB = Channel bottom width

Safety Factor of Channel Liner in Bend Area (SFLB):SFLB = Tp / TdbEffective Shear Stress on Liner in Bend (Teb):Teb = Tdb * (1-Cf) *(ns/n)2

Soil Safety Factor in Bend (SFsb):SFsb = Ta / Teb

2.2.3 User-defined Channel Methodology

The User-defined Channel Module, follows the same design methodology that isoutlined for the Channel module in 2.2.2. The difference in this module is thestarting point for input parameters. Where the channel module uses channeldimensions and discharge rate (Q) , the User-defined module starts with thecontinuity equation with Velocity (V) and channel Depth (d) as the starting inputs.

2.2.4 Channel Methodology using Mattress products

Mattress selection is performed by following the basic channel design stepsoutlined in 2.2.2. These basic design steps cover the case of a straight channelsection as well as a channel with a bend.

The roughness characteristics of mattresses are governed by the size of the stonein the mattress. Therefore, the mannings n should be determined using the D50of the stone.

Mannings roughness coefficient for Mattresses (n):

50

6/1

log23.525.2Dd

dn

a

ac where,

n = Mannings roughness coefficient, s/ft1/3da = Average flow depth in the channel, ftD50 = median diameter of stone infill, inc = Unit of conversion constant, 0.262

This equation is applicable for the range of conditions where 1.5 da / D50 185.For small channel applications, flow depths should not exceed the upper end ofthe above range.

Channels that experience conditions below the lower end of the range whereprotrusions of individual stone elements can affect the roughness, the equationbelow is used.

10

)()()(

6/1

CGfREGfFrgfd

na where,

da = average flow depth of channel, ftg = acceleration dues to gravity (3202 ft/s2)f(FR) = relates to the Froude number, see equation below = unit conversion constant, 1.49f(REG) = function of roughness element geometry, see equation belowf(CG) = function of channel geometry, see equation below

)/755.0log(28.0)(b

bFrFrf

118.0

50025.1492.0

50

434.13)(

D

T

bDTREGf

b

adTCGf

)( where,

T = Top width of the channelb = parameter describing the effective roughness concentration, where

814.0

50

453.05014.1

Dd

TDb a

Analysis of the mattress follows the same shear stress calculations as presented insection 2.2.2. The mattress channel is analyzed with three calculations: thechannel, the side slopes, and the bend.

The applicable shear stress is 1.5 < Z < 5 (lbs/ft2) and stability analysis isdetermined by

Section Safety Factor = Application Shear / Maximum Permissible Shear Stress.

Mattress sizing:

Mattress unit thickness: is a function of velocity and specified D50, (see Appendix3.8)Maximum D50 = 1/3 the Unit thicknessMaximum Gradation Size = the Unit thickness

Total Project Stability: The total project is considered stable when the Channel,Side Slopes, and Bend safety factors are all calculated to be below 1.5.

11

2.3 Spillway Design Module2.3.1 Terminology and Definitions

Spillway: A structure used to provide for the controlled release of flows from adam or levee into a downstream area. A spillway can be a controlled oruncontrolled spillway depending on the design of the water release.

For the purposes of this programs design module, the spillway is assumed to bewide, with negligible side slope gradients.

2.3.2 Spillway Design Methodology

The spillway design module calculates the flow depth based on the mannings nequation.

Mannings n equation:Flow (Q) = 2/13/2 ***486.1 SRA

nwhere,

A = Cross-Sectional AreaR = Hydraulic RadiusS = Channel Slope (averaged under uniform flow conditions)n= hydraulic roughness of channel liner (see Appendix 3.3)

Since we assume a wide spillway, side slopes are negligible so we can calculate theCross-sectional area,A = D * W where,

D = depth of water over spillwayW = width of spillway

Hydraulic Radius (R):R = D*W / (W +2D)

Therefore solve for depth (d),

2486.1

2*

2/13/2 SnQ

dWdWd

2.4 Outlet Design Module


Culvert outlets are a point of critical erosion potential, due to the change in flowvelocities from pipe to open channel areas. To prevent scour, a scour apron isoften selected. Generally scour aprons should be used only when the outletvelocity is no more than 10% greater than the downstream velocity. When thisrequirement is not met, a series of drop structures may be required.

12

2.4.2 Outlet Design Methodology

The average outlet velocity on the scour apron is dependent on the flow transitionat the end of the culvert. For circular pipes, the program uses flow depth at full orhalf capacity, and calculates the pipe area to achieve the outlet velocity.

Flow Depth at Full Capacity (DFull):8/3

5.0*335.1

SnQDFull where,

n = mannings value (hydraulic roughness) of the pipe, (see Appendix 3.9)Q = Discharge rate (cfs)S = Slope of the pipe (ft/ft)

Flow Depth at Half Capacity (DHalf):8/3

5.0*731.1

SnQDHalf

Flow Area at Full Capacity (AFull):AFull = 0.07854 *DFull2

Flow Area at Half Capacity (AHalf):AHalf = 0.07854 *DHalf2

Initial Velocity of Outlet (V):V = Q / A

Estimated Outlet Shear Stress (Td):Td = Y * D * n where,

Y = Unit weight of water (62.4)

Recommended Design Shear Stress (Tdr):Tdr = 2 * TdSafety Factor of Outlet Scour Apron (SFapron):SFapron = Tp / Tdr where,

Tp = Permissible shear stress of scour apron system (see Appendix 3.5, 3.6)

Transition Mat Protective Dimensions:Minimum Transverse Dimension (ft) = 4 * Diameterpipe (in) / 12Minimum Longitudinal Dimension (ft) = 5 * Diameterpipe (in) / 12

13

2.5 Drop Structure Module


Drop Structure: A structure designed to check channel erosion by controlling theeffective gradient and to provide for abrupt changes in gradient by means of avertical drop within the channel at intervals along the channel reach.

A drop structure effectively changes a steep bed slope into a series of gentleslopes and vertical drops. Instead of slowing down high velocity water, they aredesigned to prevent water from reaching erosive velocities.

Vertical drop structure is the most basic type and most often used in channelsystems. This structure is characterized by flow through a rectangular weirfollowed by a drop into a stilling basin.

2.5.2 Drop Structure Methodology

To evaluate the stability of a mattress or scour apron in the drop structure, theprogram uses the mannings n equation, by first determining the mannings nvalue.

Determining the Mannings n:

Channel Top Width (Wt):Wt = WB + (SL *d ) + (SR * d) where,

WB = bottom channel widthSL = Left Side SlopeSR = Right Side Sloped = channel depth

Average Depth (da):da = A / Wt where,

A = cross-sectional area

Mannings roughness coefficient for drop structures (n):

50

6/1

log23.525.2Dd

dn

a

ac where,

n = Mannings roughness coefficient, s/ft1/3da = Average flow depth in the channelD50 = median diameter of stone infillc = Unit of conversion constant, 0.262

This equation is applicable for the range of conditions where 1.5 da / D50 185.

14

For small channel applications, flow depths should not exceed the upper end ofthe above range.

Channels that experience conditions below the lower end of the range where 0.3< da/D50 < 1.5, where protrusions of individual stone elements can effect theroughness, the equation below is used.

)()()(

6/1

CGfREGfFrgfd

na where,

da = average flow depth of channelg = acceleration due to gravity (32.2 ft/s2)f(FR) = relates to the Froude number, see equation below = unit conversion constant, 1.49f(REG) = function of roughness element geometry, see equation belowf(CG) = function of channel geometry, see equation below

)/755.0log(28.0)(b

bFrFrf

118.0

50025.1492.0

50

434.13)(

D

T

bDTREGf

b

adTCGf

)( where,

T = Top width of the channelb = parameter describing the effective roughness concentration, where

814.0

50

453.05014.1

Dd

TDb a

The Cross sectional area (A):A = AL + AB + AR where,

Area of Left (AL) = * d2 *ZL where,d = depth of channelZL = slope grade of left side slope

Area of Base (AB) = WB * d where,WB = Bottom width of channel

Area of Right (AR) = * d2 *ZR where,ZR = slope grade of right side slope

15

Wetted Perimeter (P):P = PL + PB + PR where,

Left Perimeter (PL) = d *(ZL +1)0.5Base Perimeter (PB) = WBRight Perimeter (PR) = d *(ZR +1)0.5

Hydraulic Radius (R):R = A / P

Continuity Equation:Velocity (V) = Q / A

Critical Depth (yc):3/12

gB

Qy

des

c where,

Qdes = design discharge (ft3/s)B = Upstream channel widthg = acceleration due to gravity (32.2 ft/s2)

Drop Structure Design Outputs:The drop structure design used in this program is based on an aerated nappe andsubcritical flow in the upstream as well as downstream channel. This assumptionhas been made in order to represent the greatest flow conditions in order toproperly size the drop geometry. The stilling basin protects the channel againsterosion below the drop and dissipates energy. This is accomplished through theimpact of the falling water on the floor, redirection of the flow, and turbulence.

Flow geometry of a straight drop spillway

q yc

h0y1 y2

y3

L1 L2

Aerated Nappe

16

Tailwater Depth (y3):Since the tailwater must maintain the proper height within the basin, the requireddepth above the floor is calculated as follows:

y3 = 2.15 * ycThe tailwater needs to be a distance below the crest to maintain an aeratednappe. Using the crest as a reference point, this distance is calculated as:

h2 = - (h y0) where,

h2 = vertical distance of the tailwater below the crest, fth = vertical drop between the approach and tailwater channels, fty0 = normal depth in the tailwater channel, ft

Total drop (h0) :To achieve sufficient tailwater and adequate drop from the crest to tailwater, it issometimes necessary to depress the flow below the elevation of the downstreamchannel. The total drop from the crest to the stilling basin floor is:

h0 = h2 y3If h0 > than h, then depress the basin floor by the difference of Delta: = h + h0Drop Number (Nd):

30

2

ghqN d where,

q = unit discharge (ft2/s)

Drops for which Nd is greater than 1 are considered low drop structures. Onlylow drop structures should be designed with mattresses.

For a given drop height (h0) and discharge (q) the subsequent depth (y3 ) in thedownstream channel and the drop length (L1) may be computed.

L1 = 4.30 h0Nd0.27

L2 = 6.9 (y3 y2)

y1 = 1.0 h0 Nd0.22

y2 = 0.54 h0Nd0.425

y3 = 1.66 h0Nd0.27 where,

L1 = drop length, the distance from the drop wall to the position of the y2, ft

17

L2 = hydraulic jump length for mattress, fty1 = pool depth under the nappe, fty2 = depth of flow at the toe of the nappe or the beginning of the hydraulic jump,fty3 = tailwater depth sequent to the y2, ft

2.6 Vegetation Selection Module


The Vegetation Selection Module uses several project site parameters to evaluateand assign appropriate grass and legume species for the site from a database. Thefollowing parameters will determine the resulting vegetation.

Soil Type: Refers to the classification of soil by its predominate texture. Refer tothe Soil Texture chart in Appendix 3.1.

Moisture Regime: the determination of the general moisture content of the soilon site. Moisture regime in the ECMDS 5.0 is defined as:

Wet: Typical of wetlands and pond shorelines, low gradient channels withpoorly drained soils and or areas with common high water table.

Normal: Site with adequate but not excessive drainage, not subject to a highwater table

Dry: Typical of elevated, excessively drained sites with light, course texturedsoils as well as arid climates.

Vegetation Maintenance: the long-term expected maintenance planned for thesite in reference to activities such as (mowing, fertilization, irrigation, etc.).Maintenance regimes are defined in this program as:

Low - Medium: Typical of roadsides, mine reclamation and other large areaswhere vegetation is considered more functional than aesthetic. Siteoften receives little to no supplemental fertilization or irrigation.

Medium - High: Typical for areas bordering or functioning as residentiallawns and recreational turf. Site often requires a high degree ofaesthetics necessitating increased mowing, fertilization, andirrigation.

Project Location: determine the adaptation zone the project site is located inusing the Vegetal Adaptation Zone Map. The zones 1-8 are areas of knownvegetation adaptation to regional climates and biological associations.

18

3.0 Appendix3.1 Soil Texture Triangle

3.2 C-Factors for Erosion Control Products

Slope Length and GradientLength 20 ft. Length 20 - 50 ft. Length 50 ft.

3:1 3:1 2:1 2:1 3:1 3:1 2:1 2:1 3:1 3:1 2:1 2:1

Unve

getat

ed Ro

lled E

rosion

Contr

olPro

ducts

DS75 0.029 0.11 0.23 0.11 0.21 0.45 0.19 0.30 0.66S75 0.029 0.11 0.23 0.11 0.21 0.45 0.19 0.30 0.66S75BN 0.029 0.11 0.23 0.11 0.21 0.45 0.19 0.30 0.66DS150 0.004 0.106 0.13 0.062 0.118 0.17 0.12 0.18 0.22S150 0.004 0.106 0.13 0.062 0.118 0.17 0.12 0.18 0.22S150BN .00014 0.039 0.086 0.010 0.07 0.118 0.02 0.10 0.15SC150 0.001 0.048 0.10 0.051 0.079 0.145 0.10 0.11 0.19SC150BN .00009 0.029 0.063 0.005 0.055 0.092 0.01 0.08 0.12C125 0.001 0.029 0.082 0.036 0.060 0.096 0.07 0.09 0.11C125BN .00009 0.018 0.05 0.003 0.04 0.06 0.007 0.07 0.07P300 0.001 0.029 0.082 0.036 0.06 0.096 0.07 0.09 0.11SC250 0.001 0.021 0.051 0.023 0.039 0.068 0.0455 0.0555 0.0810C350 0.0005 0.015 0.043 0.018 0.031 0.050 0.035 0.047 0.057P550 .00045 0.0145 0.0425 0.0173 0.0305 .0495 0.0345 0.0465 0.0565

Hydra

ulic

Erosio

nCo

ntrol

Produ

cts

HydraCX2 0.001 0.001 0.01 0.001 0.001 0.02 0.003 0.01 0.02HydraCM 0.003 0.003 0.03 0.003 0.003 0.04 0.006 0.06 0.12GeoSkinXT 0.04 0.06 0.2 0.1 0.15 0.25 0.2 0.35 0.75GeoSkin 0.08 0.12 0.4 0.25 0.5 0.75 0.65 0.85 1.0

19

3.3 Hydraulic Roughness Coefficient for Erosion Control Products

Mannings n for Flow Depth ft (m) 0.50(0.15)

0.50 2.00(0.15-0.60)

2.00(0.60)

Unve

getat

ed Ro

lled E

rosion

Contr

olPro

ducts

DS75 0.055 0.055 0.021 0.021S75 0.055 0.055 0.021 0.021S75BN 0.055 0.055 0.021 0.021DS150 0.055 0.055 0.021 0.021S150 0.055 0.055 0.021 0.021S150BN 0.055 0.055 0.021 0.021SC150 0.050 0.050 0.018 0.018SC150BN 0.050 0.050 0.018 0.018C125 0.022 0.022 0.014 0.014C125BN 0.022 0.022 0.014 0.014P300 0.034 0.034 0.020 0.020SC250 0.040 0.040 0.011 0.011C350 0.041 0.041 0.012 0.012P550 0.041 0.041 0.013 0.013ShoreMax w/ TRM 0.040 0.040 0.026 0.026Rock Riprap 0.032 0.010Concrete 0.013 0.03

3.4 Permissible Shear Stress of Vegetation Based on Plant Height and Density

Maximum Permissible Shear lbs/ft2 (Pa)Short Duration

( 2 hours peak flow)Long Duration

(> 2 hours peak flow)

FHWA

HEC 1

5

Class A 3.70 (177) 3.70 (177)Class B 2.10 (100) 2.10 (100)Class C 1.00 (48) 1.00 (48)Class D 0.60 (29) 0.60 (29)Class E 0.35 (17) 0.35 (17)

USDA

AG Hb

k 667 Class A 7.50 (359) 7.50 (359)Class B 5.73 (274) 5.73 (274)

Class C 4.20 (201) 4.20 (201)Class D 3.33 (159) 3.33 (159)Class E 2.16 (103) 2.16 (103)

20

3.5 Permissible Shear Stress of Unvegetated Erosion Control Products

Maximum Permissible Shear lbs/ft2 (Pa)Short Duration


(> 2 hours peak flow)Un

vege

tated

Rolle

d Eros

ion Co

ntrol

Produ

ctsDS75 1.55 (74) 1.55 (74)S75 1.55 (74) 1.55 (74)S75BN 1.60 (76) 1.60 (76)DS150 1.75 (84) 1.75 (84)S150 1.75 (84) 1.75 (84)S150BN 1.85 (88) 1.85 (88)SC150 2.00 (96) 2.00 (96)SC150BN 2.10 (100) 2.10 (100)C125 2.25 (108) 2.25 (108)C125BN 2.35 (112) 2.35 (112)P300 3.00 (144) 2.00 (96)SC250 3.00 (144) 2.50 (120)C350 3.20 (153) 3.00 (144)P550 4.00 (191) 3.25 (156)ShoreMax w/ SC250 7.50 (359) 7.50 (359)ShoreMax w/ C350 8.00(383) 8.00(383)ShoreMax w/ P550 8.50 (407) 8.50 (407)

21

3.6 Permissible Shear Stress of Vegetated TRMs

Maximum Permissible Shear lbs/ft2 (Pa)PartiallyVegetated

Fully VegetatedShort Duration


(> 2 hours peak flow)Ve

getat

ed Ro

lled E

rosion

Contr

ol Pro

ducts

P300

Class A 8.0 (383) 8.0 (383) 8.0 (383)Class B 8.0 (383) 8.0 (383) 8.0 (383)Class C 8.0 (383) 8.0 (383) 8.0 (383)Class D 7.0 (335) 7.0 (335) 7.0 (335)Class E 6.0 (287) 6.0 (287) 6.0 (287)

SC250


C350


P550


ShoreMax w/ SC250(Class A-E) 10.0 (480) 10.0 (480) 10.0 (480)ShoreMax w/ C350(Class A-E) 12.0 (576) 12.0 (576) 12.0 (576)ShoreMax w/ P550(Class A-E) 14.0 (672) 14.0 (672) 14.0 (672)Rock Rip Rap NA 4 x D50Concrete NA ~ 100 (4780)

3.7 Permissible Shear Stress of Soils

Maximum Permissible Shear lbs/ft2 (Pa)Partially Vegetated Fully Vegetated

Soil C

lassifica

tions

(USD

A)

Fine Sand 0.02 (0.96) 0.02 (0.96)Sand 0.02 (0.96) 0.02 (0.96)Sandy Loam 0.035 (1.7) 0.035 (1.7)Silt Loam 0.035 (1.7) 0.035 (1.7)Loam 0.035 (1.7) 0.035 (1.7)Clay Loam 0.05 (2.4) 0.05 (2.4)Clay 0.07 (3.3) 0.07 (3.3)

22

3.8 Mattress Unit Thickness

Type Thickness(in)

Filling Stone Size Range(diameter, in)

D50(in)

DesignVelocities (ft/s)

Mattress 6 3-5 4 99 3-5 4 12

Gabion 12 4-8 6 1518 4-8 6 19

3.9 Hydraulic Roughness Coefficients for Pipe/Culvert Outlet Types

Type Mannings nConcrete or Asbestos-Cement Pipe 0.013Plastic Pipe - Smooth 0.013Plastic Pipe - Corrugated 0.02412" Corrugated Metal Pipe 0.01315" Corrugated Metal Pipe 0.01418" Corrugated Metal Pipe 0.01521" Corrugated Metal Pipe 0.01624" Corrugated Metal Pipe 0.01727" Corrugated Metal Pipe 0.01830" Corrugated Metal Pipe 0.01933" Corrugated Metal Pipe 0.0236" Corrugated Metal Pipe 0.02142" Corrugated Metal Pipe 0.02248" Corrugated Metal Pipe 0.023> 48" Corrugate Metal Pipe 0.0255Black Wrought Iron 0.014Galvanized Wrought Iron 0.016Coated Cast Iron 0.013Uncoated Cast Iron 0.014

3.10Mattress Rock Fill Densities

Type stone(lbs/ft3)Basalt 185Granite 165

Hard Limestone 165Trachytes 159Sandstone 146

Soft Limestone 140Crushed Concrete 150

23

4.0 References

1. Chen, G.Y. and g. Cotton. 1988. Design of Roadside Channels with Flexible Linings. FederalHighway Administration Hydraulic Engineering Circular #15, Simons, Li and Associates.

2. Fifield, J.S., et. al., Field Testing Erosion Control Products to Control Sediment and to EstablishDryland Grasses under Arid conditions. 1987. HydroDynamics Corp., Parker CO.

3. Foster, G. R., D.K. McCool, K.G. Renard, and W.C. Moldenhauer. 1981. Conversion of the UniversalSoil Loss Equation to SI metric Units. Journal of Soil and Water Conservation.

4. Israelsen, C.E. et. al., 1980. National Cooperative Highway Research Program Report 221, ErosionControl during Highway Construction, Utah State University, Logan, Utah.

5. Lipscomb, C.M., C.I. Thornton, D.E. Buchwald. 2002. Hydraulic Testing of SC250 and P550Vegetated with Kentucky Bluegrass. Colorado State University for North American Green. FortCollins, Colorado.

6. Lipscomb, C.M., C.I. Thornton, B.A. Smith, M.D. Robeson. 2001. Turf Reinforcement MattressPerformance Testing Phase I, Phase II, and Phase III Data Report, Colorado State University forNorth American Green, Fort Collins, Colorado.

7. North American Green, Inc. 1986. A Comparative Study of Erosion Control Materials, NorthAmerican Green, Purdue University.

8. North American Green, Inc. 1994. Comparative Testing of S75, C125, C350, and P300 ErosionControl Blankets Under Simulated Rain, Utah State Water Research Laboratory, Logan, Utah.

9. North American Green, Inc. 1993. Evaluation of Selected Erosion Control Products Using ThreeDifferent Slopes and Various Rates of Simulated Rainfall, Utah State Water Research Laboratory,Logan, Utah.

10. North American Green, Inc. 1994. High Velocity Flow Tests of C350 and P300 Reinforced Sod,Utah State Water Research Laboratory. Logan, Utah.

11. North American Green, Inc. 1993. High Velocity Flow Test of Two Root-Reinforcing Materialsunder Bare and Sodded Conditions. Utah State Water Research Laboratory. Logan, Utah.

12. Northcutt, P. and. J. McFalls. 1991-2010. Texas Department of Transportation and TexasTransportation Institute Field Testing Program for Slope Erosion Control Products, Texas A&MUniversity, College Station, TX.

13. Renard, K.G., G.R. Foster, G.A. Weesies, D.K. McCool, and D.C. Yoder. 1997. Predicting Soil Erosionby Water: A Guide to Conservation Planning with the Revised Universal Soil Loss Equation(RUSLE). USDA-ARS, Agricultural Handbook No. 703.

14. Rosewell, Colin J. and the Department of Conservation and Land Management, Soil ConservationService. 1993. Technical Handbook No. 11, 2nd Edition, SOILOSS Version 5.1: A program to assist inthe selection of management practices to reduce erosion.

24

15. Sanders, T.G., Abt. And P. Clopper. 1989. A Quantitative Test of Erosion Control Materials.Colorado State University and North American Green, Colorado State Engineering ResearchLaboratory, Fort Collins, Colorado.

16. Sprague, C.J. et. al. 2010. GeoSkin, Hydraulic Mulch over Sandy Loam, AASHTOs NationalTransportation Product Evaluation Program. TRI/Environmental. Austin, TX.

17. Sprague, C.J. et. al. 2010. HydraCM over Sandy Loam, AASHTOs National TransportationProduct Evaluation Program. TRI/Environmental. Austin, TX.

18. Sprague, C.J. et. al. 2010. HydraCX2 over Sandy Loam, AASHTOs National TransportationProduct Evaluation Program. TRI/Environmental. Austin, TX.

19. Sprague, C.J. et. al. 2010. North American Greens ShoreMax Mats over P550-TRM over SandyLoam, AASHTOs National Transportation Product Evaluation Program. TRI/Environmental.Austin, TX.

20. Temple, D., et. al. 1987. Stability Design of Grass-Lined Channels, Agricultural Handbook No.667, United States Department of Agriculture, Agricultural Research Service.

21. Thornton, C.I., A.L. Cox, M.D. Turner. 2009. Hydraulic Testing and Data Report for Six-Inch TritonFilter Mattress, Colorado State University for Tensar International Corporation, Fort Collins,Colorado.

22. Toy, T.J., G.R. Foster, and J.R. Galetovic. 1998. Guidelines for the Use of the Revised Universal SoilLoss Equation (RUSLE) Version 1.06 on Mined Lands, Construction Sites, and Reclaimed Lands.Office of Technology Transfer Office of Surface Mining and Reclamation (OSM), Western RegionCoordination Center.

23. Wall, G.J., D.R. Coote, E.A. Pringle, and I.J. Shelton (editors). 1997. RUSLEFAC: Revised UniversalSoil Loss Equation for Application in Canada. A handbook for Estimating Soil Loss from WaterErosion in Canada.

24. Wayne, M.H., S.L. Dunlap (editor). 2009. Design, Installation, and Maintenance Manual forGabion Structures, Version 1.2, Harris County Flood Control District, Houston, Texas.

25. Wischmeier, W.H. and D.D. Smith. 1978. Predicting rainfall erosion losses: A guide to conservationplanning. U.S. Department of Agriculture. Agriculture Handbook No. 537.

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