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8/2/2019 Key Mitigation Themes and Challenges in North Carolina Final
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Key Mitigation Themes and
Challenges in North CarolinaJohn R. Dorney
Atkins North America
Raleigh, NC
NC Water Resources Association Symposium Raleigh, NC
March 27, 2012
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Urban Riverine Swamp Forest
Raleigh, NC
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Three basic questions
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1. How does mitigation success vary by provider inNorth Carolina?
2. Is mitigation a failure scientifically?
3. How can we begin to achieve gain of acreageand function in North Carolina?
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Three challenges
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1. Compliance crucial
2. Flexible mitigation for buffers, coming to an EMC near
you! Flexibility needed for wetlands and streams too.
3. Functional uplift the future of mitigation?
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Three Questions
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Question 1: How does mitigation successvary by provider in North Carolina?
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Answer no real differences by provider but overall NCbetter than other states.
Previous wetland success rates lousy in NC. 20 to 42% in 1995
Recent study by DWQ basically shows same regulatorysuccess rate by provider for wetlands and streams.
Wetlands - 70% by area
Streams - 84% by length
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Question 1: How does mitigation successvary by provider in North Carolina? (cont.)
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Therefore, DOT, EEP, bankers and applicant-provided allequally good at mitigation.
Time for this argument to end in NC.
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Interesting trends
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I analyzed 19 reports on wetland regulatory success ratesacross the US from 1988 to 2010.
In the US, regulatory mitigation success (for wetlands)does not seem to be improving.
Range 18 % (MI) to 70% (NC)
Average of 48%
No statistically significant trend
Recent NC data higher than other states
Statistically significant difference; t-test; p< .001
Why is NC different?
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Mitigation success rates from various
states 1998 to 2010
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Interesting trend (cont).
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Other studies show applicant-provided mitigation usuallypoor.
My conclusion existence of EEP has curtailed small, on-site, applicant-provided mitigation in NC.
Therefore, EEP has resulted in higher mitigationregulatory success in NC.
Challenge keeping this true while EEP morphs with newstate legislation encouraging private banks.
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Question 2: Is mitigation a failurescientifically?
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AnswerNo.
I believe that the failure of mitigation is exaggerated.
Similarly, I believe that the success of mitigation is alsoexaggerated.
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Is mitigation a scientific failure? (cont.)
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Changes needed
More stream monitoring but not to the level of scientificresearch
Streambank stability Biological (aquatic insects)
Results of DWQ study
Encourage stream enhancement over restoration
Flexible (alternative) mitigation for wetlands, streamsand buffers
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Two examples of ecological success fromstream and wetland mitigation
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Orzetti, et. al. in Chesapeake Bay.
Richardson, et. al. Sandy Creek in Durham.
Note that there are also many examples of failure too.
Big lessonsencourage watershed level work and bepatient.
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Pine Valley Golf CourseWilmington, NC
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Pine Valley Golf Courserestoration project beforeconstruction
Pine ValleyGolf Courserestorationproject afterconstruction
Photos from NCSU, Stream RestorationInstitute
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Orzetti, et. al. 2010 in Chesapeake Bay
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Stream condition in piedmont streams with restoredriparian buffers in the Chesapeake Bay watershed 2010.Journal of the American Water Resources Association46(3): 473-485.
Studied 30, 1st order streams with at least 30 meter widebuffers; stream enhancement sites.
Age range from zero to 25 years old.
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Orzetti, et. al. (cont.)
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Habitat, water quality and benthic macroinvertebratemetrics generally improved with age of restored buffer.
Noticeable improvements occurring within 5 10 yearspost-restoration, leading to conditions approaching thoseof long established buffers within 10-15 years ofrestoration.
Full water quality functionality of the restored site occursin 15- 20 years
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Orzetti, et. al. (cont.)
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Orzetti, et. al. (cont.)
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Biological Water Quality Variables
Principal Component AnalysisCoded by Age of Buffer
>10 yrs
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Orzetti, et. al. (cont.)
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Implications for NC mitigation policy
MessageBE PATIENT.
Very few NC sites are > 10 years old.
Stream enhancement works to improve water quality
and aquatic life.
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Richardson, et. al. 2011 in Sandy Creek inDurham (SWAMP study)
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Sandy Creek within Duke Campus.
Conducted - i) 1 stream restoration, ii) in-line pond
(rehabilitation), and then iii) off-line constructed wetlands.
Monitoring over many years (2001 2007) by a plethoraof graduate students with LOTS of data.
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Richardson, et. al. (cont.)
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Watershed-level restorationWatershed small (600 ha or 1500 acres), andurban (21% impervious surfaces).
Figure and photo from Richardson, et. al. 2011
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Richardson, et. al. (cont.)
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decreased downstream water pulses, nutrients, coliformbacteria, sediment and stream erosion
N loads were reduced by 64% and P loads were reducedby 28%.
Only really significant reductions after all three treatments
were installed.
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Richardson, et. al. (cont.)
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Overall conclusion - multi-phased restoration of Sandy Creek
using natural stream design principles and re-contoured
adjacent wetlands resulted in a restoration of the floodplain
riparian hydrology, which reduced downstream water pulses
and stream erosion. Most importantly, we found sediment
retention and improved water quality for nutrients and coliform
bacteria leaving the watershed.
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Richardson, et. al. (cont.)
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Main conclusions
stream restoration has water quality benefit.
need watershed based approach.
Permitting (so called in-line treatment) can makewatershed approach a challenge.
To scientifically prove water quality benefit, you haveeither 1) huge monitoring costs, or 2) use free graduatestudent labor (n=150 students over 10 years).
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Corollary issue: The In-line treatmentchallenge
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Can be a permitting challenge based on EPA guidanceNovember 2001
http://www.getthedirtout.org/pdf/8c_EPA.pdf
Guidance discourages construction of stormwater treatment
measures in stream channels
Several successful sites built across state
Innes Street Market in Salisbury
Reidsville wetland Courtland Avenue Park
Raleigh wetland Fred Fletcher park
Others
http://www.getthedirtout.org/pdf/8c_EPA.pdfhttp://www.getthedirtout.org/pdf/8c_EPA.pdf8/2/2019 Key Mitigation Themes and Challenges in North Carolina Final
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The In-line treatment challenge (cont.)
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Question 3: How can we begin to achievegain of acreage and function in North
Carolina?
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Answer Change state and federal policies to encourage
this approach Available tools of NC WAM (now) and NC SAM (soon).
NC WAM and Meadow Branch example
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Meadow Branch, EEP site in RobesonCounty
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Meadow Branch berm
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Meadow Branch site after functional upliftcalculations
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Mitigation Type andLocation
Acres (appx.) Functional uplift restoration equivalents(appx. acreage)
Enhance bottomlandhardwood forest from
Low to Medium
26 acres 6.5 acre-equivalents
Enhance riverine swampforest from Low to High
8 6
Preserve bottomlandhardwood forest
10 0
Restore bottomlandhardwood forest byremoving logging road
0.82 0.82
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Three Challenges
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Challenge 1:Compliance - crucial
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Grossly underfunded by feds and state.
Without oversight, no assurance that anything works
(private or public; regulatory or scientific).
Without recent DWQ study, wed still be havingmeaningless debate about who does mitigation best in
NC.
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Challenge 1 (cont.)
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Important caveatDont be surprised when regulatorsinspect sites and see something that you dont.
Challenge for mitigation industry (private and public)FUND POSITIONS.
Fee-based positions probably most realistic
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Challenge 2:Flexible mitigation wetlands, streams andbuffers
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Needed to increase options esp. in critical watersheds
Urban
HUCs with limited sites
Examples for streams
Edwards Branch in Charlotte stream credit for watershed levelwork
Dam removal guidance
Coastal plain headwater stream guidance
Examples for wetlands?
None in NC
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Coastal Headwater Stream Mitigation Site
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Challenge 2:Flexible mitigation (cont.)
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More progress on flexible riparian buffer mitigation but stillslow.
EMC authorized to do flexible buffer mitigation by statestatute over a decade ago.
Draft flexible buffer mitigation
Draft rules before Water Quality Committee of EMC six times in pastthree years!
On WQC agenda for May 2012.
C
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Challenge 2 (cont.)
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Expand buffer mitigation options esp. in service areaswith few options for traditional mitigation.
Do not assume these options will be cheaper most willbe more expensive.
Big Lesson: Often (always?) Flexible cheaper.
Recommendation discuss with your favorite EMCmember to get rules to Public Hearing.
Ch ll
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Challenge 3:Functional uplift
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NC WAM/NC SAM is the tool!
Everyone needs to think outside the box somewhat to makethis work.
Need to determine
how to use,
how to monitor,
etc.
Interagency Review Team oversight/approval
Allowable under existing DWQ 401 rules
Ch ll 3 ( )
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Challenge 3 (cont.)
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Wetlands
Meadow Branch example (coastal plain)
Functional uplift makes this site useful.
Without functional uplift, site has 0.82 acres of restoration
equivalents.
With functional uplift, site has 13.32 acres of restorationequivalents.
Indian/Howard Creek example (piedmont) Functional uplift probably not useful since most wetlands small (
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