key mitigation themes and challenges in north carolina final

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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Biological Water Quality Variables

Principal Component AnalysisCoded by Age of Buffer

>10 yrs


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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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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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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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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.pdf


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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 (

key mitigation themes and challenges in north carolina final

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