750.6 Erosion Control and Energy Dissipation - Revision history

Hoskir: /* 750.6.3.3 Rock Ditch Liner */ updated per RR 3656 (last paragraph only)

2023-04-19T15:00:31Z

750.6.3.3 Rock Ditch Liner: updated per RR 3656 (last paragraph only)

← Older revision		Revision as of 10:00, 19 April 2023
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	</center>		</center>
	The lowest practical type of rock ditch liner should be selected based on permissible shear stress calculations. For constructability, short intervals of different types of rock ditch liner should be avoided. When economical, the larger size type of rock ditch liner should be extended to eliminate short segments of a smaller type rock. Type 1 and 2 are very similar in cost, so it is desired to extend Type 2 through a short segment where Type 1 is calculated to be acceptable. Similarly, Type 4 should be extended through short Type 3 segments if both are required. This is not the case for Type 2 and 3, because Type 3 requires a bedding layer and Type 2 doesn't, making the cost for Type 3 significantly higher than Type 2. ~~Geotextile filter fabric should~~ be used under all rock ditch liners except where grades are less than four percent and the District Soils and Geology Technologist determines that the geotextile is not necessary. Generally, geotextile fabrics are not required for clays or silty clays with a liquid limit greater than 30. Aggregate bedding material is required under all Type 3 and Type 4 rock ditch liner. Details for rock ditch liners, geotextile ~~fabrics~~ and bedding materials are shown in the standard plans.		The lowest practical type of rock ditch liner should be selected based on permissible shear stress calculations. For constructability, short intervals of different types of rock ditch liner should be avoided. When economical, the larger size type of rock ditch liner should be extended to eliminate short segments of a smaller type rock. Type 1 and 2 are very similar in cost, so it is desired to extend Type 2 through a short segment where Type 1 is calculated to be acceptable. Similarly, Type 4 should be extended through short Type 3 segments if both are required. This is not the case for Type 2 and 3, because Type 3 requires a bedding layer and Type 2 doesn't, making the cost for Type 3 significantly higher than Type 2. Erosion control geotextile shall be used under all rock ditch liners. Details for rock ditch liners, geotextile and bedding materials are shown in the standard plans.

	===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===		===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===

Smithk: updated links

2022-04-19T18:36:32Z

updated links

← Older revision		Revision as of 13:36, 19 April 2022
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	===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===		===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===

	Several types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats]].		Several types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.9 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.9 Erosion Control Blankets and Turf Reinforcement Mats]].

	===750.6.3.5 Gabion Lining===		===750.6.3.5 Gabion Lining===
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	\| Rock Ditch Liner Type 4 \|\| <center>6*</center>		\| Rock Ditch Liner Type 4 \|\| <center>6*</center>
	\|-		\|-
	\| Turf Reinforcement Mats \|\| <center>3.5 – 14<br/>See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10]]</center>		\| Turf Reinforcement Mats \|\| <center>3.5 – 14<br/>See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.9 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.9]]</center>
	\|-		\|-
	\| Gabion Lining \|\| align="center"\|Varies<br/> See [[#750.6.3.5 Gabion Lining\|EPG 750.6.3.5]]		\| Gabion Lining \|\| align="center"\|Varies<br/> See [[#750.6.3.5 Gabion Lining\|EPG 750.6.3.5]]
	\|-		\|-
	\|align="center"\|Temporary\|\|Erosion Control Blankets\|\|align="center"\| < 3.5<br/> See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10]]		\|align="center"\|Temporary\|\|Erosion Control Blankets\|\|align="center"\| < 3.5<br/> See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.9 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.9]]
	\|-		\|-
	\|colspan="3"\|'''*''' Values are approximate, actual design values should be calculated.		\|colspan="3"\|'''*''' Values are approximate, actual design values should be calculated.

Smithk: updated several std plan links

2019-12-10T18:18:41Z

updated several std plan links

← Older revision		Revision as of 13:18, 10 December 2019
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	Rock lining is used for scour protection at culvert outlets when it is determined that the natural streambed will not withstand scour and the culvert outlet velocity is 20 ft/s or less. The rock lining is rectangular in shape and consists of dumped rock blanket material placed in an excavation at the culvert outlet. This material is to be paid for as Rock Lining. Since the material is dumped and not hand placed, no payment will be made for placing rock lining. This treatment is not used where rock is existing in the channel.		Rock lining is used for scour protection at culvert outlets when it is determined that the natural streambed will not withstand scour and the culvert outlet velocity is 20 ft/s or less. The rock lining is rectangular in shape and consists of dumped rock blanket material placed in an excavation at the culvert outlet. This material is to be paid for as Rock Lining. Since the material is dumped and not hand placed, no payment will be made for placing rock lining. This treatment is not used where rock is existing in the channel.

	The minimum dimensions of the rock lining are a function of the culvert size and are given in [~~http~~://modot.~~mo.gov~~/~~business~~/~~standards_and_specs/documents/60970.pdf~~ Standard Plan 609.70]. The culvert size in this table is given as the diameter of a circular pipe. However, the dimensions shown can be applied to box or arch culverts of equivalent waterway area.		The minimum dimensions of the rock lining are a function of the culvert size and are given in [https://www.modot.org/media/16884 Standard Plan 609.70]. The culvert size in this table is given as the diameter of a circular pipe. However, the dimensions shown can be applied to box or arch culverts of equivalent waterway area.

	The mean velocity at the downstream end of the rock lining may be calculated by the Manning Formula applied to the channel cross-section through the rock lining.		The mean velocity at the downstream end of the rock lining may be calculated by the Manning Formula applied to the channel cross-section through the rock lining.
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	Details of the energy dissipating headwalls are shown in Standard Plans 604.10 to 604.15:		Details of the energy dissipating headwalls are shown in Standard Plans 604.10 to 604.15:
	:[~~http~~://modot.~~mo.gov/business/standards_and_specs~~/~~documents~~/~~60410.pdf~~ Standard Plan 604.10]		:[https://www.modot.org/media/16845 Standard Plan 604.10]
	:[~~http~~://modot.~~mo.gov~~/~~business~~/~~standards_and_specs/documents/60411.pdf~~ Standard Plan 604.11]		:[https://www.modot.org/media/16846 Standard Plan 604.11]
	:[~~http~~://modot.~~mo.gov~~/~~business~~/~~standards_and_specs/documents/60412.pdf~~ Standard Plan 604.12]		:[https://www.modot.org/media/16847 Standard Plan 604.12]
	:[~~http~~://modot.~~mo.gov/business/standards_and_specs~~/~~documents~~/~~60413.pdf~~ Standard Plan 604.13]		:[https://www.modot.org/media/16848 Standard Plan 604.13]
	:[~~http~~://modot.~~mo.gov~~/~~business~~/~~standards_and_specs/documents/60414.pdf~~ Standard Plan 604.14]		:[https://www.modot.org/media/16849 Standard Plan 604.14]
	:[~~http~~://modot.~~mo.gov~~/~~business~~/~~standards_and_specs/documents/60415.pdf~~ Standard Plan 604.15]		:[https://www.modot.org/media/16850 Standard Plan 604.15]

	Unlike stilling basins which utilize a hydraulic jump for energy dissipation, the impact type energy dissipator requires no tailwater for successful performance. In addition, a properly designed impact type energy dissipator will outperform a hydraulic jump as an energy dissipation device. Energy dissipation is achieved by virtue of the vertical hanging baffle. When the high velocity flow exits the culvert, it strikes the baffle and is turned upstream in vertical eddies, thus reducing the energy and velocity of flow.		Unlike stilling basins which utilize a hydraulic jump for energy dissipation, the impact type energy dissipator requires no tailwater for successful performance. In addition, a properly designed impact type energy dissipator will outperform a hydraulic jump as an energy dissipation device. Energy dissipation is achieved by virtue of the vertical hanging baffle. When the high velocity flow exits the culvert, it strikes the baffle and is turned upstream in vertical eddies, thus reducing the energy and velocity of flow.

EPGsysop: /* 750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats */ Per Env'l, the types of erosion control blankets were increased

2018-05-17T19:39:08Z

750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats: Per Env'l, the types of erosion control blankets were increased

← Older revision		Revision as of 14:39, 17 May 2018
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	===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===		===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===

	~~Five~~ types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats]].		Several types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats]].

	===750.6.3.5 Gabion Lining===		===750.6.3.5 Gabion Lining===

EPGsysop: /* 750.6.3.3 Rock Ditch Liner */Per BR, table from Sec 609.50 added for clarity/convenience to highway designers

2017-12-11T14:55:25Z

750.6.3.3 Rock Ditch Liner: Per BR, table from Sec 609.50 added for clarity/convenience to highway designers

@@ Line 81: / Line 81: @@
 :''γ'' = specific weight of water, 62.4 lb/ft<sup>3</sup>
 :d<sub>50</sub> = mean diameter stone size, ft
 Setting the permissible shear stress equation equal to the shear stress equation given in [[#750.6.2.1 Shear Stress|EPG 750.6.2.1 Shear Stress]] multiplied by a safety factor the following sizing equation for d<sub>50</sub> can be derived.

Smithk: /* 750.6.3 Types of Ditch Protection */ Per Bridge, minor corrections

2014-10-22T12:16:39Z

750.6.3 Types of Ditch Protection: Per Bridge, minor corrections

Smithk: /* 750.6.3.3 Rock Ditch Liner */ minor correction

2014-07-29T12:39:27Z

750.6.3.3 Rock Ditch Liner: minor correction

← Older revision		Revision as of 07:39, 29 July 2014
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	:<math>\tau_p\,</math> = permissible shear stress for rock lining, lb/ft<sup>2</sup>		:<math>\tau_p\,</math> = permissible shear stress for rock lining, lb/ft<sup>2</sup>
	:F = Shield's parameter, dimensionless = specific weight of stone, lb/ft<sup>3</sup> (typically 165 lb/ft<sup>3</sup>)		:F = Shield's parameter, dimensionless
	:''~~<math>\gamma</math>~~'' = specific weight of water, 62.4 lb/ft<sup>3</sup>		:''γ<sub>s</sub>'' = specific weight of stone, lb/ft<sup>3</sup> (typically 165 lb/ft<sup>3</sup>)
			:''γ'' = specific weight of water, 62.4 lb/ft<sup>3</sup>
	:d<sub>50</sub> = mean diameter stone size, ft		:d<sub>50</sub> = mean diameter stone size, ft

Smithk: /* 750.6.2.1 Shear Stress */ Per Bridge, minor clarifications

2014-06-23T13:41:01Z

750.6.2.1 Shear Stress: Per Bridge, minor clarifications

← Older revision		Revision as of 08:41, 23 June 2014
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	The bend coefficient is given by		The bend coefficient is given by

	{\| style="margin: 1em auto 1em auto"		::{\| style="margin: 1em auto 1em auto"; align="left"; margin-right:300px;
	\|-		\|-
	\|K<sub>b</sub> = 2.00 \|\|width="20"\| \|\|width="150"\| R<sub>c</sub>/T<2		\| <font size = 3.0> K<sub>b</sub> = 2.00 \|\|width="20"\| \|\|width="150"\| <font size = 3.0> R<sub>c</sub>/T<2
	\|-		\|-
	\|K<sub>b</sub> = 2.38 - 0.209 (R<sub>c</sub>/T) + 0.0073 (R<sub>c</sub>/T)<sup>2</sup> \|\| \|\| 2<R<sub>c</sub>/T<10		\|<font size = 3.0> K<sub>b</sub> = 2.38 - 0.209 (R<sub>c</sub>/T) + 0.0073 (R<sub>c</sub>/T)<sup>2</sup> \|\| \|\| <font size = 3.0> 2<R<sub>c</sub>/T<10
	\|-		\|-
	\|K<sub>b,/sub> = 1.05 \|\| \|\|R<sub>c</sub>/T>10		\|<font size = 3.0>K<sub>b</sub> = 1.05 \|\| \|\|<font size = 3.0> R<sub>c</sub>/T>10
	\|}		\|}

	:where:		:where:

	:K<sub>b</sub> = bend coefficient - function of Rc/T		:K<sub>b</sub> = bend coefficient - function of R<sub>c</sub>/T
	:R<sub>c</sub> = radius to centerline of channel, ft		:R<sub>c</sub> = radius to centerline of channel, ft
	:T = top width of channel, ft		:T = top width of channel, ft

Smithk: Per Bridge, updated to correspond to latest edition of HEC-15.

2014-06-10T19:36:04Z

Per Bridge, updated to correspond to latest edition of HEC-15.

Show changes

Smithk: /* 750.6.3.3 Rock Ditch Liner */ updated link

2013-04-17T15:38:54Z

750.6.3.3 Rock Ditch Liner: updated link

← Older revision		Revision as of 10:38, 17 April 2013
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	\|}		\|}

	For additional information see [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.4.2.9 Erosion ~~Stabilization~~ Mats ~~and Blankets~~\|Storm Water Pollution Prevention Plan (SWPPP) - Erosion ~~Stabilization~~ Mats ~~and Blankets~~]].		For additional information see [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.4.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|Storm Water Pollution Prevention Plan (SWPPP) - Erosion Control Blankets and Turf Reinforcement Mats]].

	===750.6.3.4 Paved Ditch===		===750.6.3.4 Paved Ditch===

← Older revision		Revision as of 07:16, 22 October 2014
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	===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===		===750.6.3.4 Erosion Control Blankets and Turf Reinforcement Mats===

	Five types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.4.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.4.3.10 Erosion ~~Stabilization~~ Mats ~~and Blankets~~]].		Five types of erosion control blankets are available for temporary use. Turf reinforcement mats can be used to supplement permanent erosion control. Refer to [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats]].

	===750.6.3.5 Gabion Lining===		===750.6.3.5 Gabion Lining===
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	<div id="Permissible Shear Stresses for Ditch Protection"></div>		<div id="Permissible Shear Stresses for Ditch Protection"></div>
	{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"		{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"
	\|+ '''~~TYpical~~ Permissible Shear Stresses for Ditch Protection'''		\|+ '''Typical Permissible Shear Stresses for Ditch Protection'''
	! rowspan="2" style="background:#BEBEBE"\|Lining Category !! rowspan="2" style="background:#BEBEBE"\| Type !!colspan="2" style="background:#BEBEBE"\|Permissible Unit Shear Stress		! rowspan="2" style="background:#BEBEBE"\|Lining Category !! rowspan="2" style="background:#BEBEBE"\| Type !!colspan="2" style="background:#BEBEBE"\|Permissible Unit Shear Stress
	\|-		\|-
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	\| Rock Ditch Liner Type 4 \|\| <center>6*</center>		\| Rock Ditch Liner Type 4 \|\| <center>6*</center>
	\|-		\|-
	\| Turf Reinforcement Mats \|\| <center>3.5 – 14<br/>See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.4.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.4.3.10]]</center>		\| Turf Reinforcement Mats \|\| <center>3.5 – 14<br/>See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10]]</center>
	\|-		\|-
	\| Gabion Lining \|\| align="center"\|Varies<br/> See [[#750.6.3.5 Gabion Lining\|EPG 750.6.3.5]]		\| Gabion Lining \|\| align="center"\|Varies<br/> See [[#750.6.3.5 Gabion Lining\|EPG 750.6.3.5]]
	\|-		\|-
	\|align="center"\|Temporary\|\|Erosion Control Blankets\|\|align="center"\| < 3.5<br/> See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.4.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.4.3.10]]		\|align="center"\|Temporary\|\|Erosion Control Blankets\|\|align="center"\| < 3.5<br/> See [[806.8 Storm Water Pollution Prevention Plan (SWPPP)#806.8.6.3.10 Erosion Control Blankets and Turf Reinforcement Mats\|EPG 806.8.6.3.10]]
	\|-		\|-
	\|colspan="3"\|'''*''' Values are approximate, actual design values should be calculated.		\|colspan="3"\|'''*''' Values are approximate, actual design values should be calculated.