Erosion Prevention and Erosion Prevention and Sediment Control Sediment Control

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21 Φεβ 2014 (πριν από 3 χρόνια και 5 μήνες)

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1
Erosion Prevention and
Erosion Prevention and
Sediment Control
Sediment Control
Presentation Outline
Presentation Outline
Erosion and Sedimentation 101
Regulatory Background
EPSC Practices
– Runoff Measures
– Erosion Prevention
– Sediment Control
Inspection and Maintenance
The Good, the Bad and the Ugly
Sediment
Sediment


Natural erosion:
Natural erosion:


Also referred to as geologic erosion
Also referred to as geologic erosion
--
--
is relatively slow
is relatively slow


Most rapid along shorelines and stream channel
Most rapid along shorelines and stream channel


Vital factor in maintaining environmental balance
Vital factor in maintaining environmental balance


Produces about 30% of all sediment in U.S.
Produces about 30% of all sediment in U.S.


Accelerated erosion:
Accelerated erosion:


Refers to erosion occurring at increased rate usually
Refers to erosion occurring at increased rate usually
because of removal of natural vegetation or alteration of
because of removal of natural vegetation or alteration of
ground contour
ground contour


Accounts for 70% of all sediment generated in U.S.
Accounts for 70% of all sediment generated in U.S.


Construction and agriculture are main causes.
Construction and agriculture are main causes.
Impacts of Sedimentation
Impacts of Sedimentation


Annually about 8 billion metric
Annually about 8 billion metric
tons of sediment will reach
tons of sediment will reach
ponds, rivers and lakes in the US
ponds, rivers and lakes in the US
each year.
each year.


Roughly two
Roughly two
-
-
thirds comes from
thirds comes from
agriculture and forestry practices
agriculture and forestry practices


One
One
-
-
third comes from active
third comes from active
construction or land development
construction or land development
Expected Erosion Rates
Expected Erosion Rates
(Tons/Acre/Year)
(Tons/Acre/Year)
1.
1.
Forest Land
Forest Land
2.
2.
Farm Land
Farm Land
3.
3.
Construction Sites
Construction Sites
1 or greater
1 or greater
15 or greater
15 or greater
100 or greater
100 or greater
Sediment
Sediment


Adverse impacts:
Adverse impacts:


Screens out sunlight/ reduces clarity
Screens out sunlight/ reduces clarity


Fills channels and reduces capacity
Fills channels and reduces capacity


sediments can fill up ponds and reservoirs
sediments can fill up ponds and reservoirs


sedimentation can plug culverts and storm drains
sedimentation can plug culverts and storm drains


Pollutants attach to sediment particles
Pollutants attach to sediment particles


legal action
legal action


additional costs and penalties
additional costs and penalties


delays in schedule
delays in schedule


Property damage from flooding
Property damage from flooding
2
Sediment
Sediment


Factors Influencing Erosion:
Factors Influencing Erosion:


Climate
Climate


Frequency, intensity and duration of rainfall,
Frequency, intensity and duration of rainfall,
particularly
particularly


Vegetative Cover
Vegetative Cover


Topography
Topography


Soil Characteristics:
Soil Characteristics:


Texture
Texture


Percentage of OM
Percentage of OM


Structure
Structure


Permeability
Permeability
NPDES Storm Water Program
NPDES Storm Water Program


Point Source Pollution
Point Source Pollution


Discharges from manufacturing
Discharges from manufacturing
facility pipe or some other readily
facility pipe or some other readily
identifiable source.
identifiable source.


Nonpoint Source Pollution
Nonpoint Source Pollution


Discharges that are less easily
Discharges that are less easily
identifiable such as runoff from
identifiable such as runoff from
urbanized areas, agricultural areas
urbanized areas, agricultural areas
and construction sites.
and construction sites.
Background of NPDES
Background of NPDES


1987
1987
-
-
An amendment to
An amendment to
federal Clean Water Act, called
federal Clean Water Act, called
Water Quality Act (WQA),
Water Quality Act (WQA),
required EPA to develop
required EPA to develop
phased program to regulate
phased program to regulate
storm water discharges under
storm water discharges under
NPDES Program.
NPDES Program.
Background of NPDES
Background of NPDES


1990
1990
-
-
USEPA issued NPDES Phase I
USEPA issued NPDES Phase I
Storm Water Rule:
Storm Water Rule:


Large and Medium Municipal Separate
Large and Medium Municipal Separate
Storm Sewer Systems (MS4s)
Storm Sewer Systems (MS4s)


Storm Water Discharges Associated
Storm Water Discharges Associated
with Industrial Activity, non
with Industrial Activity, non
-
-
construction activities
construction activities


Storm Water Discharges Associated
Storm Water Discharges Associated
with Industrial Activity, construction
with Industrial Activity, construction
sites disturbing
sites disturbing
>
>
5 acres
5 acres
Background of NPDES
Background of NPDES


1999
1999
-
-
USEPA issued NPDES
USEPA issued NPDES
Phase II Storm Water Rule:
Phase II Storm Water Rule:


Small MS4s
Small MS4s


Storm Water Discharges Associated
Storm Water Discharges Associated
with Industrial Activity, construction
with Industrial Activity, construction
sites disturbing
sites disturbing
>
>
1 acre
1 acre
EPSC Best Management
EPSC Best Management
Practices
Practices
3
Construction BMPs
Construction BMPs


Runoff Measures
Runoff Measures


Erosion Prevention
Erosion Prevention


Sediment Control
Sediment Control
Runoff Control BMPs
Runoff Control BMPs


Pipe slope drains
Pipe slope drains


Runoff diversion measures
Runoff diversion measures


Temporary stream crossings
Temporary stream crossings


Construction de
Construction de
-
-
watering
watering
Pipe Slope Drain
Pipe Slope Drain


Description:
Description:


Pipe slope drains are used when it is necessary
Pipe slope drains are used when it is necessary
for water to flow down slope without causing
for water to flow down slope without causing
erosion, especially before slope has been
erosion, especially before slope has been
stabilized or before permanent drainage
stabilized or before permanent drainage
structures are installed.
structures are installed.


Pipe slope drains can be temporary or
Pipe slope drains can be temporary or
permanent depending on installation and
permanent depending on installation and
material used.
material used.
Pipe Slope Drain
Pipe Slope Drain
Pipe Slope Drain
Pipe Slope Drain
Pipe Slope Drain Video
Pipe Slope Drain Video
Pipe Slope Drain
Pipe Slope Drain


Troubleshooting:
Troubleshooting:
4
Pipe Slope Drain
Pipe Slope Drain


Troubleshooting:
Troubleshooting:
Erosion Prevention BMPs
Erosion Prevention BMPs


Surface roughening
Surface roughening


Bench terracing
Bench terracing


Temporary stabilization
Temporary stabilization


Mulching
Mulching


Erosion control blankets
Erosion control blankets


Turf reinforcement mats
Turf reinforcement mats
Correct
Incorrect
Erosion Prevention BMPs
Erosion Prevention BMPs


Final Stabilization
Final Stabilization


Riprap for Channel Stabilization
Riprap for Channel Stabilization


Outlet Protection
Outlet Protection


Dust Control
Dust Control


Polyacrylamide
Polyacrylamide
(PAM)
(PAM)
Erosion Control Blankets
Erosion Control Blankets


Description:
Description:


Erosion Control Blankets (ECBs) are temporary
Erosion Control Blankets (ECBs) are temporary
erosion control BMPs that hold seed and soil in
erosion control BMPs that hold seed and soil in
place, degrading over time period of
place, degrading over time period of
approximately 1
approximately 1
-
-
to 3
to 3
-
-
years as vegetation
years as vegetation
becomes established.
becomes established.
Erosion Control Blankets
Erosion Control Blankets
Erosion Control Blankets
Erosion Control Blankets


ECB Video
ECB Video
5


Troubleshooting:
Troubleshooting:
Erosion Control Blankets
Erosion Control Blankets


Troubleshooting:
Troubleshooting:
Erosion Control Blankets
Erosion Control Blankets
Sediment Control BMPs
Sediment Control BMPs


Temporary sediment basins
Temporary sediment basins


Sediment traps
Sediment traps


Silt fence
Silt fence


Rock ditch check
Rock ditch check


Sediment tube ditch check
Sediment tube ditch check
Sediment Control BMPs
Sediment Control BMPs


Stabilized construction
Stabilized construction
entrance
entrance


Inlet protection
Inlet protection


Rock sediment dikes
Rock sediment dikes
Silt Fence
Silt Fence


Description:
Description:


Temporary perimeter controls around sites where
Temporary perimeter controls around sites where
there is soil disturbance due to construction
there is soil disturbance due to construction
activities.
activities.


Consist of
Consist of
geotextile
geotextile
fabric stretched across
fabric stretched across
posts (non
posts (non
-
-
reinforced) or preferably with wire
reinforced) or preferably with wire
support fence (reinforced).
support fence (reinforced).


Lower edge of fence is vertically trenched and
Lower edge of fence is vertically trenched and
covered by compacted backfill.
covered by compacted backfill.


Should never be installed in areas of
Should never be installed in areas of
concentrated flow
concentrated flow
Silt Fence
Silt Fence
Silt Fence with Tie-backs
6
Silt Fence
Silt Fence


Troubleshooting:
Troubleshooting:
Silt Fence
Silt Fence


Troubleshooting:
Troubleshooting:
Silt Fence
Silt Fence


Troubleshooting:
Troubleshooting:
Sediment Tube Ditch Check
Sediment Tube Ditch Check


Description:
Description:


Sediment tubes are elongated tubes of
Sediment tubes are elongated tubes of
compacted geotextiles, curled excelsior wood,
compacted geotextiles, curled excelsior wood,
natural coconut fiber or hardwood mulch.
natural coconut fiber or hardwood mulch.
Sediment tubes may be installed in drainage
Sediment tubes may be installed in drainage
conveyance swales as ditch checks to help
conveyance swales as ditch checks to help
reduce effects soil erosion and retain sediment.
reduce effects soil erosion and retain sediment.
Sediment Tube Ditch Check
Sediment Tube Ditch Check
Sediment Tube Ditch Check Video
Sediment Tube Ditch Check Video
Sediment Tube Ditch Check
Sediment Tube Ditch Check
7
Inspection and Maintenance
Inspection and Maintenance
Site Inspections
Site Inspections


Represent link between approved
Represent link between approved
plans and implementation
plans and implementation


Required for compliance with
Required for compliance with
NPDES permit
NPDES permit


Only way to stay informed of a
Only way to stay informed of a
site
site


s condition
s condition


Can reduce liability of site if
Can reduce liability of site if
practices are proven to be
practices are proven to be
installed and maintained properly
installed and maintained properly


Important for record keeping
Important for record keeping
1.
1.
The inspection date
The inspection date
2.
2.
Name, title and qualifications of
Name, title and qualifications of
inspector
inspector
3.
3.
Weather information since last
Weather information since last
inspection
inspection
4.
4.
Description of any discharges
Description of any discharges
occurring
occurring
5.
5.
Locations of discharges of sediment
Locations of discharges of sediment
or other pollutants from the site
or other pollutants from the site
Inspection Reports
Inspection Reports
6.
6.
Locations of BMPs that
Locations of BMPs that
need maintenance
need maintenance
7.
7.
Locations of BMPs that
Locations of BMPs that
failed or proved
failed or proved
inadequate for a particular
inadequate for a particular
location
location
8.
8.
Locations where additional
Locations where additional
BMPs are needed
BMPs are needed
9.
9.
Corrective action required
Corrective action required
& implementation dates
& implementation dates
Inspection Reports
Inspection Reports
Inspection Frequency
Inspection Frequency


Depends on local/state
Depends on local/state
regulatory authority
regulatory authority


Typically every 7 days
Typically every 7 days
and after every 0.5
and after every 0.5


rainfall
rainfall


May be more frequent
May be more frequent
for some aspects
for some aspects


Construction entrance
Construction entrance


Perimeter controls
Perimeter controls


Rain
Rain
guage
guage
BMP Maintenance
BMP Maintenance


These practices all require
These practices all require
varying degrees of
varying degrees of
maintenance
maintenance


Critical to effective operation
Critical to effective operation


Requirements vary with
Requirements vary with
practice
practice


Sediment traps and rock ditch
Sediment traps and rock ditch
checks when sediment depth
checks when sediment depth
reaches
reaches
½
½
design volume
design volume


Silt fence, fabric drop inlet
Silt fence, fabric drop inlet
protection, etc at 1/3 design
protection, etc at 1/3 design
height
height
8
Bottom Line
Bottom Line




Properly designed
Properly designed
and installed
and installed
practices are
practices are
NOT
NOT
enough
enough




Good site inspection
Good site inspection
and BMP
and BMP
maintenance
maintenance
programs are
programs are
essential to avoid off
essential to avoid off
site impacts
site impacts
The Good, The Bad and The Ugly
The Good, The Bad and The Ugly


BMP Examples
BMP Examples


Proper installation and well
Proper installation and well
-
-
functioning
functioning


Practices in need of maintenance
Practices in need of maintenance


Practices in poor condition or
Practices in poor condition or
failing
failing
9
10
Questions?
Questions?