Summary: Permitting ditch maintenance, permit requirements ditch maintenance
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Fact Sheet A3
Permit
Requirements for
Ditch Maintenance
This fact sheet provides an overview of regulatory requirements and guidance related to:
Permitting for ditches with natural flow
Other local permits that may apply
NPDES Municipal Stormwater Permit Requirements
Mapping
Mapping ditches is required by the National
Pollutant Discharge Elimination System (NPDES)
Phase I and Phase II municipal stormwater
permits if they eventually drain to an outfall or
discharge point that has a specified diameter.
Ditch attributes that must be mapped according
to the NPDES municipal stormwater permit
include:
Standard Operating Procedures (SOPs)
The following ditch-related activities shall be
addressed as part of a Municipal Operation and
Maintenance (O&M) Program according to the
NPDES municipal stormwater permit:
Cleaning of culverts that convey stormwater in
ditch systems
Ditch maintenance
Maintaining roadside areas, including
vegetation management
Erosion and sediment control
Landscape maintenance and vegetation
disposal
Conveyance type (e.g., pipe, ditch)
Material
Size (if known)
Associated drainage area
Land use
Ditch and roadside vegetation maintenance,
Photo source: WSDOT
Ditch maintenance
Recordkeeping
Proper disposal
February 7, 2019
Phase I and Phase II
Municipal Stormwater
Permit References
Phase I: S5.C.2.a and S5.C.2.b
Phase II: S5.C.3 (S5.C.4 in
2019-2024 permit)
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Phase I NPDES Municipal
Stormwater Permit References
Phase II NPDES Municipal
Stormwater Permit References
NPDES Municipal Stormwater Permit Requirements
Regulated municipal stormwater permit areas as of 2018
Figure source: Washington Department of Ecology
Mapping: S5.C.2.a and S5.C.2.b
SOPs: S5.C.9.e (S5.C.10.e in 2019-2024 permit)
Recordkeeping: S5.C.9.h
(S5.C.10.h in 2019-2024 permit)
Disposal: G10 and Appendix 6
Mapping: S5.C.3.a. (S5.C.4.a in
2019-2024 permit)
SOPs: S5.C.5.f (S5.C.7.e in 2019-
2024 permit)
Recordkeeping: S5.C.5.i (S5.C.7.h
in 2019-2024 permit)
Disposal: G10 and Appendix 6
Recordkeeping
Permittees must maintain records of inspections and
maintenance or repair activities for up to five years.
Disposal
Street waste solids (including sediment accumulations
removed during ditch maintenance) may be reclaimed,
recycled, or reused when allowed by local codes and
ordinances. Soils that are identified as contaminated
pursuant to Chapter 173-350 WAC must be disposed at a
qualified solid waste disposal facility.
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Use or disposal options for the sediment removed from ditches will depend on the characterization of
the waste. Roadside ditch cleanings contaminated by spills or other releases known or suspected to
contain dangerous waste must be handled following the Dangerous Waste Regulations (Chapter 173-
303 WAC). If testing determines materials are not dangerous waste, but contaminants are present,
consult with your local health department for disposal options.
Stormwater Management Manual for Western Washington
The Volume IV of the Stormwater Management Manual for Western Washington (SWMMWW)
describes best management practices (BMPs) for maintenance of roadside ditches (S416 BMPs):
“Maintain roadside ditches to preserve the condition and capacity for which they were originally
constructed, and to minimize bare or thinly vegetated ground surfaces. Maintenance practices should
provide for erosion and sediment control.†Operational BMPs include:
Remove vegetation when flow is blocked
or excess sediment has accumulated
Appropriately dispose of dirt and debris
from road surfaces after completing ditch
cleaning activities
Do not apply fertilizer unless needed
Perform seeding, fertilizer application,
and harvesting in late spring and/or early
fall, where possible
The frequency of ditch inspections and cleaning is not specified in the NPDES municipal stormwater
permit or SWMMWW and can be set by the local jurisdiction. Considerations for establishing
inspection and maintenance frequencies include road type, land use type, and previous maintenance
records. See Fact Sheet A2 – Prioritizing Ditches for Inspection and Maintenance for more
information.
Disposal Considerations
Inspect ditches regularly to identify
sediment accumulations and
localized erosion
Inspect culverts regularly for scour or
sedimentation at inlet and/or outlet
Clean as needed
Remove trash and debris
Note: Several Phase I jurisdictions (e.g., King County, Pierce County, City of Seattle) and the
Washington State Department of Transportation (WSDOT) have developed their own stormwater
manuals which have been reviewed for equivalency to the SWMMWW by Ecology. Refer to the
stormwater manual that your jurisdiction has adopted to determine if additional requirements related
to maintenance of roadside ditches apply.
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Plans must be submitted with the Simplified
Application for HPA and should address the following:
Permitting for Ditches that Convey Natural Flow
For regulatory purposes, a ditch that conveys natural flow should be treated as a stream. This may
include ditches that are hydraulically connected and within ¼ mile of a stream or wetland (see
local codes and ordinances). In some cases, a ditch may not be properly mapped as natural flow
conveyance. If maintenance crews encounter a ditch that appears to be conveying natural flow,
planned maintenance should be put on hold until:
(1)
Appropriate permits are obtained, and
(2)
Crews are trained on stream-specific
Hydraulic Project Approval (HPA)
A Washington State HPA is required for projects that
will use, divert, obstruct, or change the natural flow or
bed of any of the salt or fresh waters of the state. HPA
is administered by the Washington Department of Fish
and Wildlife (WDFW) under Chapter 220-660 WAC.
A Simplified Application for HPA can be submitted
for road maintenance work which includes, but is not
limited to:
Culvert cleaning Ditch maintenance
Plan and cross-view drawings
Project location in relation to the ordinary
high water mark (OHWM) for freshwater,
the mean higher high water line (MHHW)
for saltwater, the channel migration zone,
and the 100-year floodplain
Equipment that will be used and where
it will be operated
Construction sequencing
Sediment and erosion control BMPs
Plan for removal (if any) of riparian
vegetation
WDFW uses an Aquatic Permitting System (APPS) for the HPA application. This application will include
proof of State Environmental Policy Act (SEPA) compliance, and can be converted to a Joint Aquatic
Resource Permit Application (JARPA) if needed (several permitting agencies accept this form). A copy
of the HPA or Federal Permit for the maintenance activity must be on site during the work.
Natural flow in ditch at upstream road crossing
Natural flow in ditch
maintenance practices (see Fact Sheet F3 –
Maintaining Ditches that Convey Natural
Flow)
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Other Potential Permits
Consult local codes and ordinances for additional specific requirements related to ditch maintenance
activities. Code requirements that regulate activities, such as vegetation management, in and near
streams may vary by jurisdiction. When natural flow is present, additional local permits and submittals
may be necessary, including the following:
Critical areas permit
Clearing and grading permit
Shoreline permit
Habitat permit (for proposed cleaning in
riparian areas that are priority habitat
areas designated by the local jurisdiction)
Vegetation management plan
NPDES permit for herbicide applications
(note: herbicide applications should
always be performed by a licensed,
qualified professional)
U.S. Army Corps of Engineers Seattle
District regional conditions for NWPs
Natural flow in ditch
Nationwide Permit (NWP)
In 2017, the U.S. Army Corps of Engineers established 52 Nationwide Permits that regulate dredging
and placement of fill in wetlands, streams, lakes, and marine waters and may apply to ditch
maintenance activities if maintenance is performed in ditches with natural flow. Some activities that
may require a permit include, but aren’t limited to:
Placement of sandbags Dredging sediment Reshaping ditches
Permitting for Ditches that Convey Natural Flow
The NWP does not apply to activities that only involve cutting or removing vegetation above the
ground, where the activity neither substantially disturbs the root system nor involves mechanized
pushing, dragging, or other similar activities that redeposit excavated soil. The following NWPs may
apply to ditch maintenance activities:
This fact sheet was developed by Herrera Environmental Consultants with input from King County and the Regional Operations and Maintenance
Program (ROADMAP). Project funding was provided by a National Estuary Program grant from the Washington State Department of Ecology.
Maintenance – NWP 3
Bank Stabilization – NWP 13
Linear Transportation Projects – NWP 14
Reshaping Existing Drainage Ditches – NWP 41
Fact Sheet A3
Permit
Requirements for
Ditch Maintenance
This fact sheet provides an overview of regulatory requirements and guidance related to:
Permitting for ditches with natural flow
Other local permits that may apply
NPDES Municipal Stormwater Permit Requirements
Mapping
Mapping ditches is required by the National
Pollutant Discharge Elimination System (NPDES)
Phase I and Phase II municipal stormwater
permits if they eventually drain to an outfall or
discharge point that has a specified diameter.
Ditch attributes that must be mapped according
to the NPDES municipal stormwater permit
include:
Standard Operating Procedures (SOPs)
The following ditch-related activities shall be
addressed as part of a Municipal Operation and
Maintenance (O&M) Program according to the
NPDES municipal stormwater permit:
Cleaning of culverts that convey stormwater in
ditch systems
Ditch maintenance
Maintaining roadside areas, including
vegetation management
Erosion and sediment control
Landscape maintenance and vegetation
disposal
Conveyance type (e.g., pipe, ditch)
Material
Size (if known)
Associated drainage area
Land use
Ditch and roadside vegetation maintenance,
Photo source: WSDOT
Ditch maintenance
Recordkeeping
Proper disposal
February 7, 2019
Phase I and Phase II
Municipal Stormwater
Permit References
Phase I: S5.C.2.a and S5.C.2.b
Phase II: S5.C.3 (S5.C.4 in
2019-2024 permit)
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Phase I NPDES Municipal
Stormwater Permit References
Phase II NPDES Municipal
Stormwater Permit References
NPDES Municipal Stormwater Permit Requirements
Regulated municipal stormwater permit areas as of 2018
Figure source: Washington Department of Ecology
Mapping: S5.C.2.a and S5.C.2.b
SOPs: S5.C.9.e (S5.C.10.e in 2019-2024 permit)
Recordkeeping: S5.C.9.h
(S5.C.10.h in 2019-2024 permit)
Disposal: G10 and Appendix 6
Mapping: S5.C.3.a. (S5.C.4.a in
2019-2024 permit)
SOPs: S5.C.5.f (S5.C.7.e in 2019-
2024 permit)
Recordkeeping: S5.C.5.i (S5.C.7.h
in 2019-2024 permit)
Disposal: G10 and Appendix 6
Recordkeeping
Permittees must maintain records of inspections and
maintenance or repair activities for up to five years.
Disposal
Street waste solids (including sediment accumulations
removed during ditch maintenance) may be reclaimed,
recycled, or reused when allowed by local codes and
ordinances. Soils that are identified as contaminated
pursuant to Chapter 173-350 WAC must be disposed at a
qualified solid waste disposal facility.
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Use or disposal options for the sediment removed from ditches will depend on the characterization of
the waste. Roadside ditch cleanings contaminated by spills or other releases known or suspected to
contain dangerous waste must be handled following the Dangerous Waste Regulations (Chapter 173-
303 WAC). If testing determines materials are not dangerous waste, but contaminants are present,
consult with your local health department for disposal options.
Stormwater Management Manual for Western Washington
The Volume IV of the Stormwater Management Manual for Western Washington (SWMMWW)
describes best management practices (BMPs) for maintenance of roadside ditches (S416 BMPs):
“Maintain roadside ditches to preserve the condition and capacity for which they were originally
constructed, and to minimize bare or thinly vegetated ground surfaces. Maintenance practices should
provide for erosion and sediment control.†Operational BMPs include:
Remove vegetation when flow is blocked
or excess sediment has accumulated
Appropriately dispose of dirt and debris
from road surfaces after completing ditch
cleaning activities
Do not apply fertilizer unless needed
Perform seeding, fertilizer application,
and harvesting in late spring and/or early
fall, where possible
The frequency of ditch inspections and cleaning is not specified in the NPDES municipal stormwater
permit or SWMMWW and can be set by the local jurisdiction. Considerations for establishing
inspection and maintenance frequencies include road type, land use type, and previous maintenance
records. See Fact Sheet A2 – Prioritizing Ditches for Inspection and Maintenance for more
information.
Disposal Considerations
Inspect ditches regularly to identify
sediment accumulations and
localized erosion
Inspect culverts regularly for scour or
sedimentation at inlet and/or outlet
Clean as needed
Remove trash and debris
Note: Several Phase I jurisdictions (e.g., King County, Pierce County, City of Seattle) and the
Washington State Department of Transportation (WSDOT) have developed their own stormwater
manuals which have been reviewed for equivalency to the SWMMWW by Ecology. Refer to the
stormwater manual that your jurisdiction has adopted to determine if additional requirements related
to maintenance of roadside ditches apply.
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Plans must be submitted with the Simplified
Application for HPA and should address the following:
Permitting for Ditches that Convey Natural Flow
For regulatory purposes, a ditch that conveys natural flow should be treated as a stream. This may
include ditches that are hydraulically connected and within ¼ mile of a stream or wetland (see
local codes and ordinances). In some cases, a ditch may not be properly mapped as natural flow
conveyance. If maintenance crews encounter a ditch that appears to be conveying natural flow,
planned maintenance should be put on hold until:
(1)
Appropriate permits are obtained, and
(2)
Crews are trained on stream-specific
Hydraulic Project Approval (HPA)
A Washington State HPA is required for projects that
will use, divert, obstruct, or change the natural flow or
bed of any of the salt or fresh waters of the state. HPA
is administered by the Washington Department of Fish
and Wildlife (WDFW) under Chapter 220-660 WAC.
A Simplified Application for HPA can be submitted
for road maintenance work which includes, but is not
limited to:
Culvert cleaning Ditch maintenance
Plan and cross-view drawings
Project location in relation to the ordinary
high water mark (OHWM) for freshwater,
the mean higher high water line (MHHW)
for saltwater, the channel migration zone,
and the 100-year floodplain
Equipment that will be used and where
it will be operated
Construction sequencing
Sediment and erosion control BMPs
Plan for removal (if any) of riparian
vegetation
WDFW uses an Aquatic Permitting System (APPS) for the HPA application. This application will include
proof of State Environmental Policy Act (SEPA) compliance, and can be converted to a Joint Aquatic
Resource Permit Application (JARPA) if needed (several permitting agencies accept this form). A copy
of the HPA or Federal Permit for the maintenance activity must be on site during the work.
Natural flow in ditch at upstream road crossing
Natural flow in ditch
maintenance practices (see Fact Sheet F3 –
Maintaining Ditches that Convey Natural
Flow)
Fact Sheet A3 – Permit Requirements for Ditch Maintenance
Other Potential Permits
Consult local codes and ordinances for additional specific requirements related to ditch maintenance
activities. Code requirements that regulate activities, such as vegetation management, in and near
streams may vary by jurisdiction. When natural flow is present, additional local permits and submittals
may be necessary, including the following:
Critical areas permit
Clearing and grading permit
Shoreline permit
Habitat permit (for proposed cleaning in
riparian areas that are priority habitat
areas designated by the local jurisdiction)
Vegetation management plan
NPDES permit for herbicide applications
(note: herbicide applications should
always be performed by a licensed,
qualified professional)
U.S. Army Corps of Engineers Seattle
District regional conditions for NWPs
Natural flow in ditch
Nationwide Permit (NWP)
In 2017, the U.S. Army Corps of Engineers established 52 Nationwide Permits that regulate dredging
and placement of fill in wetlands, streams, lakes, and marine waters and may apply to ditch
maintenance activities if maintenance is performed in ditches with natural flow. Some activities that
may require a permit include, but aren’t limited to:
Placement of sandbags Dredging sediment Reshaping ditches
Permitting for Ditches that Convey Natural Flow
The NWP does not apply to activities that only involve cutting or removing vegetation above the
ground, where the activity neither substantially disturbs the root system nor involves mechanized
pushing, dragging, or other similar activities that redeposit excavated soil. The following NWPs may
apply to ditch maintenance activities:
This fact sheet was developed by Herrera Environmental Consultants with input from King County and the Regional Operations and Maintenance
Program (ROADMAP). Project funding was provided by a National Estuary Program grant from the Washington State Department of Ecology.
Maintenance – NWP 3
Bank Stabilization – NWP 13
Linear Transportation Projects – NWP 14
Reshaping Existing Drainage Ditches – NWP 41
Filename:
factsheet-a3-permitting-final.pdf
File Type:
pdf
File Size:
2 MB
Categories:
Mapping, Source Control, Stormwater Planning
