National Flood Policy—ASFPM 2015 Recommendations
C. Stormwater & Watershed Management
Recommendation
Watershed Management
C-1 PROMOTE WATERSHED APPROACHES
a) “Recommend or require holistic, LID, GI and No
Adverse Impact (NAI) stormwater approaches at state
and local levels for the management of runoff to
reduce flood damage throughout watersheds and for
the protection of water quality, natural systems and
groundwater recharge.”
[FEMA, EPA, USACE, MitFLG]
Explanation/rationale
The goal of watershed management should be the
preservation of natural processes and existing habitat
while protecting/improving water quality, water for
beneficial uses, groundwater recharge and ensuring any
potential increase in future flood hazards is mitigated.
Green infrastructure (GI) and Low Impact Development
(LID) can be defined as the natural and man-made
landscapes and features that can be used to manage
b) Emphasize and foster the integration of floodplain, runoff. Examples of natural green infrastructure include
habitat, and water quality programs within all forests, meadows and floodplains. Examples of manwatershed management approaches at state and local made green infrastructure include green roofs, rain
levels.
gardens and rainwater cisterns. NAI incorporates LID and
[States, EPA]
GI.
c) Consider both flood risk reduction and water quality This may require modification of current watershed
benefits in all FEMA HMGP and EPA Section 319 and planning guidelines from EPA to include current and
Smart Growth and Resilience demonstration projects future flood hazard impacts.
[FEMA, EPA]
The most effective local programs tend to be those that
See: J-2, J-3, K-4, O-6, H-1, H-12
address multiple issues, not single issue or single agency
programs.
C-2 States and EPA should require watershed (stormwater) Without the control of increased runoff (peak and
management that prevents an increase in flood flows by volume) of runoff from new development, the cost of
new development or redevelopment with attention to development is transferred from the developer to
control of not only peak flows, but also the volume of property downstream. Several states mandate matching
runoff and the timing of runoff for a range of flows from a the peak flow for one or more design events for the prechannel forming event to moderate (100-year) flood and post-development condition. It is better to also
event.
control the volume of total runoff for a range of events
and use the natural condition for the pre-developed
See: K-4, F-11, R-12
state.
[States, EPA]
C-3 Wetlands (including appropriate buffers) and other This type of activity is awarded CRS points in watershed
flood storage areas inside and outside of the 1% chance management plans, recognizing the interdependence of
floodplain should be preserved to maintain or reduce the jurisdictions and protecting the assets of the
downstream increases in flood frequency and heights. upstream community while avoiding increases in
States and communities should not allow wetlands and flooding of the downstream community/properties. This
storage areas to be filled without appropriate mitigation, will also define the potential liability for changes that
including complete replacement of their storage function. might damage downstream investments or assets, as
would C4.
See: K-3
[USACE, FEMA, MitFLG, States]
NFPPR policy rec and explanations
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Section C Stormwater draft 1-28-15
National Flood Policy—ASFPM 2015 Recommendations
C-4 STORMWATER—FLOOD RISK INTEGRATION
a) “EPA, as part of MS4 permits should consider requiring
the control of the peak and volume of the 1% annual
chance event to prevent severe erosion of stream
channels, pollution, and damage to adjoining
structures during flood events which creates more
pollution.
Standards vary from 2-5 year for EPA and 1% chance or
100 year for FEMA. Because these standards are based
on the probability of an event, they reflect regional
conditions and can still be uniform nationwide. For
example, a 2 year standard for the water quality event
and 100 year for flooding may be acceptable if designs
to address the tiered approach are utilized.
b) EPA and FEMA should collaborate to address the
disconnect between water quality and quantity focus
that results in exacerbating current problems for one
while mitigating the other.
This is needed to ensure that agency programs
complement each other as much as possible and help
states and communities that implement and utilize these
programs do not get conflicting or otherwise
nonintegrated rules/guidance.
See: F-11, Q-11, R-4, H-12
[EPA, FEMA]
C-5 Riparian buffers should be required as a condition of Buffers are one of the most effective means to protect
all new development to protect water quality, flood both water quality and habitat
storage, ecosystem services and development outside of
the buffers.
See: K-3
[States, MitFLG]
C-6 EPA should consider extending the standards of the Small feeder streams are critical to downstream water
Clean Water Act to all development greater than ½ acre quality and natural ecosystem functions
instead of the current 1 acre and to somehow address
agricultural practices.
[EPA]
NFIP Support of Effective Stormwater Programs
C-7 As a prerequisite for a Class 4 rating, require CRS
communities to require all new development and
redevelopment to use No Adverse Impact (NAI), Low
impact development (LID) and green infrastructure (GI)
techniques to the maximum extent possible for each site
to mitigate their adverse impacts.
See: K-4, J-2, O-6
[FEMA]
C-8 Encourage/incentivize (CRS and other) runoff
reduction through the use of infiltration, low impact
development and green infrastructure techniques to
reduce and manage flood flows and runoff to help in
protecting water quantity and water quality.
This would put more emphasis on using NAI, LID and GI
“to the maximum extent possible” by the most highly
rated of the CRS communities. This also means that
developers would use the techniques that are
appropriate for their community. This relates to floods
by reducing impervious surfaces and maintaining
infiltration to avoid increased flows due to development
This would give some focus on infiltration and permeable
surfaces rather than a focus on moving water away from
the land via conveyance.
Credits could also come in form of advantageous sliding
cost-shares for grants, disaster assistance, or other
incentives
[FEMA, EPA, MitFLG]
NFPPR policy rec and explanations
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Section C Stormwater draft 1-28-15