NORTH CAROLINA DEPARTMENT OF TRANSPORTATION

NORTH CAROLINA DEPARTMENT OF TRANSPORTATION STREAM MITIGATION PROGRAM

JosephH. Mickey, Jr. JamesA. Wasseen,II

North Carolina Wildlife ResourcesCommission Division of Inland Fisheries Raleigh

2005

1 This monitoring reportis submittedaspartial fulfillment of the off-site stream mitigation agreementbetweenthe North CarolinaDepartmentof Transportation (NCDOT) andNorth CarolinaWildlife ResourcesCommission(NCWRC) for the R-529 US 421 road improvementprojectin WataugaCounty. Underthis agreement,a total of 14,814linear feet of streammitigationis requiredby the United StatesAnny Corpsof Engineers(USACE)and 7,407linear feetof mitigationis requiredby the North Carolina Division of WaterQuality(NCDWQ). Mickey and Scott(2002)describedsurvey methods,site conditions,and projectobjectivesin the as-builtreport. The purposeof this reportis to summarizethe monitoring datacollectedin 2002 and 2004from 2183 linear feetof an unnamedtributaryto PeakCreeklocatedonthe Bareproperty,Ashe County (Figure 1). Monitoring datais comparedwith datasubmittedin the 2002 as-builtreport (Mickey and Scott2002). Monitoring The purposeof the Bare mitigation projectis to improvein-streamhabitatandreduce bank erosionfrom a previouslychannelizedstream. Sinceconstructionwas completedin 2001 the streamhasremaineda C/b4streamtype (Rosgen1996). The as-built survey was completedon November8, 2001,the first and secondyearmonitoring surveyswere completedon October22, 2002and on May 4, 2004. Thesesurveysincluded longitudinalprofiles, channelcross-sections, pebblecounts,stemcounts(planted treesnivestakes),anda photo log of the site (Appendix 1). Bankfull rain eventswere monitoredthroughreviewof the United StatesGeologicalSurvey's SouthFork New River gage(03161000)nearJefferson,North Carolina,by photos(Appendix1) and by personalobservationsof bankfull stagestakesplacedon site. Sincecompletionof the asbuilt survey(Mickey and Scott2002)therehavebeensevenbankfull or greaterthan bankfull eventsatthe site (Table 1). It shouldbenotedthatthe fall of 2002through2003 was an unusuallywet period. Of the sevenbankfull eventsthat occurredduring this time the stormon November19,2003wasthe mostsevere.This stormdropped6 inchesof rain in lessthan8 hours on the site (personalcommunication,landowner). This storm causeda new headcut channelto becreatedacrossa point bar at station2+90 (Figure 3.2) anddamagedthe cattlecrossinggates(Appendix 1). Thesedamagedareaswere repairedin 2004. LongitudinalProfile Monitoring Sinceconstructionwascompletedin September2001, severalchanneladjustments haveoccurredto the longitudinalprofile (Figure2). The 2002monitoring surveyshows thatthe streambottomaggradedalonga seriesof small rock vanesfrom stations0+17 to 0+89,filling in the small constructedpools(Figure2.1). In 2004this sectiondegraded slightly towardspost-constructionelevations,however,the pools were not reestablished. The aggradingthat took placein the constructedpools in this sectionwas not unexpected. The rock vanesconstructedin this areawere an experimentto seeif pools could be createdalongthis reachutilizing riprapplacedon the streambankby the landowneryears ago. Apparently,the streamgradethroughthis areawastoo low andthe bed load settled out in the constructedpools.

As a resultof the November19,2003 stormevent,a majorchangeoccurredin the longitudinalprofile from stations1+12to 2+33 (Figure2.1). During this stormevent, bed load materialsbeganto depositin the channelat station2+33,causinga sidechannel to developacrossa point bar upstreamat station2+18. As this newbar channel deepened,streamvelocitieswerereducedin the main channelandadditionalstreambed materialsbeganto be depositedin the main channelfrom stations2+33 to3+30 (Figure 2.1). At station3+30the newbar channelconnectedwith the main channel. From station3+30to the endof the projectsomeminor differencesbetweenthe 2002and 2004 longitudinalsurveyscanbe noted(Figures2.1, 2.2 and2.3). At station18+75a new, deeppool wasformedand from stations19+54to 20+26an existingpool was filled in by streambedmaterials. Thesechangesarea direct resultof the November19, 2003flood (Appendix 1). Repairwork wascompletedon July 7.,2004from station2+33 to 3+30to reshapethe point bar andeliminatethe newly formedbar channel. Cross-sectionMonitoring Nine cross-sections wereestablishedduringthe post-constructionsurveyand resurveyedduring 2002and2004. Two additionalcross-sections were addedin 2004,one to monitor a potentialproblemareaandthe otherto monitor a stablepool maintainedby root wads. CROSS-SEcnON 1+78 -pool (Figure3.1): This cross-section is locatedover a longpool. Therehavebeensomechangesin this cross-section profile from 2001 to 2002 asa resultof the November19,2003flood. The left bankhasincreasedin height approximately1.4feetnearthe watersedge. This is a direct resultof the flood depositing bedmaterialsalongthis area. The centerthalwaghasbeeneliminateddueto a 0.37ft rise of the mid-sectionof the streamchannel,causinga shift in the thalwagto the left and right banks. Thesechangeshavenot causedchannelinstability asthe banksexhibit stableelevationsandbreaksin slope. CROSS-SECTION2+90 -pool (Figure3.2): This cross-section is locatedovera meanderpool stabilizedby rootwads. The left and right bankshaveremainedstablebut somemajor changeshaveoccurredacrossthe wide point bar. The November19,2003 flood createda 15 ft wide headcut andresultingchannelacrossthe bar from stations 0+33to 0+48. This headcut channeldoesnot extendall the way acrossthe bar, but the potentialexists for it to do so overtime. If this occursthe meanderandpool at this locationwould be eliminated. Depositionfrom the November19,2003 flood increased the heightof the bar 0.87ft from stations0+48to 0+67.7andfilled in the pool at the base of the root wads 1.07ft. This areawasrepairedon July 7, 2004by reshapingthe point bar to eliminatethe newchannel. CROSS-SEcnON 6+29 -pool (Figure3.3): This is a new cross-sectionlocated overa pool on a sectionof erodingbank that developedafterthe November19,2003 flood. The bankhad neverbeena problemuntil this flood event. This cross-section was establishedto monitorthe erodingbank andto monitorrepairsto the bank that were completedon July 7, 2004.

2

CROSS-SECTION7+19 -pool (Figure3.4): This cross-section is locatedovera pool stabilizedby root wads. The post-construction and2002monitoring cross-section surveysindicatedno majorchangesin this cross-section.The 2004 surveyshowsa deepeningof the pool by 1.17ft andsomedepositionon the point bar, a resultof the November19,2003 flood. Both banksexhibit the sameelevationsandbreaksin slope from previoussurveys. CROSS-SECTION10+35-rift1e (Figure3.5): This cross-section is locatedovera stablerift1e immediatelyupstreamof the secondlivestockcrossingat longitudinalprofile station10+64. This wasa wide, shallowrift1eareaandthe purposeof this cross-section wasto monitorthe naturalchangesin the channeloncelivestockwere excludedfrom the riparianzone. The width of the wettedperimeterindicateshow muchthis channelhas narrowedfrom 2001 to 2004. The wettedperimeterdecreasedfrom 18.3ft in 2001,to 13 ft in 2002,andto 9.2 ft in 2004. The left bankhas slowly widenedcreatinga sloping bank, effectivelynarrowingthe channelwhile the right bankhasremainedstable. As the vegetationalongthe slopeof the left bank hasbecomeestablished,it hastrapped materialssuspended during bankfull events,effectivelyrebuildingthe left bank with a stableslope. A wet spring seepis locatedfrom cross-sectionstation0+72to 0+75. CROSS-SECTION11+68 -riffle (Figure3.6): This cross-section is locatedovera riffle which hasa high left bankandlong, sloping point bar on the right bank. Therehas beena noticeablechangein the maximumheightof the point bar, an increaseof 0.78 ft from the post-constructionsurvey. This is attributedto vegetationtrappingstreambed materialsduring flood events. Sincecompletionof the streamwork at this cross-section, the thalwaghasaggradedby 0.45 ft. Both banksexhibit the sameelevationand breaksin slope. CROSS-SECTION16+81-riffle (Figure3.7): This cross-section is locatedovera riffle which hasa high right bank andlong, sloping point bar on the left bank. Therehas beenan increasein the heightof the point bar by 0.53 ft and correspondingaggradations of the streambedby 0.81 ft. While therehavebeensomeadjustmentsto the channel sinceconstruction,therehasbeenlittle lateralmovementandthe channelis stable. The unusualelevationsfor post-constructionstation0+03.3and2 year monitoring station 0+56 is attributedto incorrectrod readingsdue to the rod beaconhavingto behandheld on the rod. This canbe the only explanationfor theseodd elevationssincethe bank profiles havenot changedduringthe monitoringperiod. CROSS-SECTION 17+08 -pool (Figure 3.8): This cross-sectionwas added to monitor the pool formed by root wads used to stabilize the bank. At the time of the 2004 survey, this area was not experiencing any stability problems. CROSS-SECTION 17+57 -riffle (Figure 3.9): This cross-sectionis located in a run/riffle complex below a rock weir. The tops of the banks show some ground settling has occurred since construction. There have been some minor adjustments to the bankfull and floodplain areasthat have captured sedimentsduring high water storm events. There has been a 0.56 ft aggradation of the channel thalweg between post-

3

constructionandyear1 monitoring. This changein thalwegelevationsis a resultof streamchanneladjustmentsfollowing construction.The thalwaghad a minor adjustment of + 0.10ft betweenyear 1 andyear2 monitoringperiod. CROSS-SEcnON 18+42-riffle (Figure3.10): This cross-sectionmonitorsa stable riffle that was not impactedby constructionotherthan someminor gradingalongthe top of the right bank. This untouchedriffle showsthe samesedimentbuild-upalongthe banksas othercross-sections.The thalwagdeepenedby 0.31 ft from the year 1 to year 2 monitoringsurvey,bringing it backin line with the post-construction thalwegdepth. Monitoring of this site showsthatthe streamthalwegwill increaseor decreasein elevationfrom yearto yearbasedon the numberandmagnitudeof bankfull or greater events. CROSS-SECTION20+80 -pool (Figure3.11): This cross-sectionmonitorsa constructedpool stabilizedwith root wadsbelowa rock weir. The right bankhas aggradedslightly dueto sedimentsbeingdepositedin the bankfull and flood proneareas. The thalwag of the pool hasaggraded,reducingthe depthof the pool by 0.82 ft. It will be interestingto observeif this pool continuesto fill or if it will scourout following the nextbankfull event. These11 cross-sections indicatethattherehasbeenno noticeablelateralmovement of the channelsinceconstructionwascompletedin September 2001. Most of the crosssectionsexhibit somebuild up of the streambanks dueto depositionof materialsduring stormevents. Thesethalwagchangesdo not indicatean unstablechannel,but a channel bed that is constantlychangingdueto stormevents. PebbleCount Monitoring Bed material analysis was conducted in a riffle at cross-section 18+42 (Figure 4). Pavementanalysis (100 sample count wetted perimeter) has changed very little from post-construction to 2004. The D5oobserved in the pavementwas 16 mm, 26 mm and 27 mm for post-construction year 1, and year 2 monitoring. Since the post-construction survey, the D5ohas changed from medium gravel to coarsegravel. The D95was 94 mm, 93 mm, and 98 mm for post-construction, year 1 and year 2 monitoring. The D95has remained in the small cobble particle size range. The bed material has exhibited little change since completion of the project.

Vegetationmonitoring A total of 2,229bareroot treesandlive stakeswereplantedin the 3.02 acre conservationeasement areaduring 2001-2003.The site is divided into four areaswith a total countof stems(treesandlive stakes)beingmadein eacharea(Table 1). The May 2004 surveyfound 1,076stemswerepresent;a 48.3%(356.3stemsper acre)survival rate(Table 1). The densityof stemsexceedsthe 320 stems/acrerequiredfor woody speciesplantedat mitigation sitesthroughyearthree (USACE2003). It shouldbe noted that vegetationcountsare difficult dueto the small sizeof manyof the plantingsandhigh

4

forbs growth at the time of the stemcounts. Of the 14 tree/shrubspeciesplanted,those having a greaterthan 50%survivalrateincludedsilky willow Salix sericea(100%),tag alder Alnus serrulata(100%),flowering dogwoodCornusjlorida (50.7%),sycamore Platanusoccidentalis(65%)and black cherryPrunusserotina(65.6%)(Table2). The 100%survival rate for tag alderand silky willow is attributedto the high rateof natural regenerationby thesespecies. LivestockExclusion The livestockexclusionplan includesfive wateringtanks,two livestockcrossingsand approximately4,400ft of fencing. Livestockno longerhaveaccessto the riparian area alongthe unnamedtributaryandtwo small springseepslocatedon the Bareproperty. The two livestockcrossingsweredamagedduring the September29, 2002and November 19,2003 stonnevents. Both crossingswererepairedafter eachstonnevent. A changeof designwasneededat the crossingsso that flood waterdebriswould not catchon the fencingcrossingthe stream. Debris buildup on the barbedwire causedfencepoststo be pulled from their positions,resultingin the failure of the fencingacrossthe creek. To addressthis problema removablecablesystemwasdevelopedthat could be strungacross the streamonly whencattlewererotatedbetweenpastures. Conclusion Monitoring dataindicatethatthe streamchannelhasmademinor adjustmentsin the longitudinalprofIle andcross-sections asa resultof large stormevents. The streamis stable. However,minor repairsduring the fall of2004 wererequiredat cross-sections 2+90 and 6+29 andat the two livestockcrossings.As the riparian vegetationimproves, streambankstability shouldcontinueto improvedueto the exclusionof livestockfrom the riparianzone. The monitoring surveywill be conductedagainduring2005. References Mickey, J. H. and S. Scott. 2002. As-built reportfor the Bare mitigation site, unnamedtributaryto PeakCreek,Ashe County. North CarolinaWildlife ResourcesCommission,Raleigh. Rosgen,D. L. 1996. Applied river morphology. Wildland Hydrology Books. Pagosa Springs,Colorado. USACE (US Army Corpsof Engineers),Wilmington District, U. S. Environmental ProtectionAgency,North CarolinaWildlife ResourcesCommission,andthe North CarolinaDivision of WaterQuality. 2003. "StreamMitigation guidelines".Wilmington, North Carolina.

5

FIGURE1. Bare stream mitigation site on an unnamed tributary to Peak Creek, New River drainage, Ashe County, North Carolina.

6

0

-.:i 0 C"I

I

.-. 0 0 C"I

0

i tIS

U

I

;..

0;)

.:;: 0;)

u

0;)

~ Q)

...: r.E

~ .s

~ 0 I

~

~

N

-

~

o~ 0

]

-a d

0-

0 ""'

~

Q)

So 0

o~

00

~ 0

"g

e

o:§ 00

0

d

6

0 0

f"--

+

0

!i f/)

~ 0

00

.~

's ~ ~

~

.:S f/)

f/)

~ 0 .~

C)

O

S0;)

8

;:a p..

] -.a .a

~ 0

.bi>

~ f-i

~

~

7

-g

g

0

-= N

U

~

~

~

~ 0 0

I

~

+

+

0 0

[ f::

0

~ "'Iii e 0 rIJ

~

f::

~ .~ 0

~ OJ

u

g

;:s A

~f:: 00

"] f::

0

~ N

~

~ ~

8

'-g

s

.~ 0

U N

~ 0 ~

~ .-om co r-..co cocor-..r-..r-..r-..r-..r-..r-..r-..r-..

(y)

It)

~

C'>('\I.-'-

N

a a N

a

a .N

0 0 0 N

a a

.9

OJ c: "':

'c m

I.-

~

~ I

N

~

u c:

.-ro

JY~ In ...

c: .Q

0

0)

.C)

c:

---"~ ... ~o

Q) ~

0

~~~ c:

Q)~

c:

~ l () I 0

U

0 ..." :3

~

0 I'--

In

.:::.

c: 0 u 0

..!. In

0

Do

~

0

~

0 0 Il)

~

0 0

..;

~ +

0 0

N N I 0

0

v

-+

~ 0

~ t1 S

~ r/)

0

jg .~ O

SQ q)

~ ~

~

.S

~ 0

"2 .~

rf')

~

N

~

~

9

FIGURE3. Cross-sectioncomparisons, Bare mitigation site, UT Peak Creek, Watauga County, 2001-2004.

FIGURE3.1. Cross-section station 1+78, pool.

FXGURE 3.2. Cross-section station 2+90, riffle.

10

~

FIGURE3. Continued.

-+-2

Year Monitoring -BKF

FIGURE 3.3 Cross-sectionstation6+29,pool, a new crosssectionin 2004.

FIGURE 3.4. Cross-section station 7+19, pool.

11

FIGURE3. Continued.

FIGURE3.5. Cross-section station 10+35, riftle.

0

10

20

30

40 Distance

--Post-Construction

-1

Year Monitoring

50

60

70

80

(II) -2

Year M>nitoring

-BKF

FIGURE3.6. Cross-section station 11+68, riffle.

12

FIGURE3. Continued.

FIGURE 3.7. Cross~sectionstation 16+81, riffle.

FIGURE3.8. Cross-section station 17+08, pool, new cross section in 2004.

13

FIGURE3. Continued.

FIGURE3.9. Cross-section station 17+57, riffle.

FIGURE 3.10. Cross-section station 18+42, rifile.

14

FIGURE 3. Continued.

81 80 79 78

g 77 l ,g~

76

Q)

w 75 74 73 72

0

10 -+-

20

Post-Construction

30

-1

40

Distance (11) Year Monitoring -+-2

50

60

7'0

Year Monitoring -+-BKF -

FIGURE3.11.Cross-sectionstation20+80,pool.

15

0 0

.q. NI

.-. 0 0 N

0

~ U ~ Of)

.§ tIS

~ --i

e

u

0>--E

C

.~ E .-CI>

N --

.9'-C 0

CI> .2

I

Nt--

~I§

I I

~NO>~

r-- 1

vI "-N ~U) '- CI> -t

N~

C)~ c:: E

0---

"£:: E

.0...

~

0>

"~

:go> L-

EEEEE

'Ot

EEEEE 00000

(QIl)Qoq-ll) ..-(") 1l)(X)

0)

-

I 0;,0.Dt:3 ~ ~ ~ f-; ~ ~ 5:0'~

C+-.~~~~

§ 00~.~

~~.~ >.

>.O~

0 ::> ~

c,0

:>

'a .~ V)

N I:l:I ...:j

~~ ~ """""Q)rJ)~~~~~..cQ)~ 0 ~ ~ -~ Q) ~ ~ ' ~ ~ ~

~ ~ ..E f ~ -§ ] .§ ..5 ~ ~ 0 -~ , ~ ~ ~~'-.JC,.)Q~,,-;;Q.,Q.,~~

00

~

~

\0

t-o"

00 ~ ~

00

N

\0 -q-

~

~

-

N

N~

0'1 N

~

r--

.cnO;)-

~

0;)

$-0

cn

0;>

~ >

~.,... --. .g "(d ~

-0;)

°,.9. ~~ ,.9.~

~~~>. ' =-= -a G"'oo 0,

~ .,...

~

t+... 0

0;) ~

0

~t+...

_.,... t+... ~

~ cn

ro

~ cn 0

.,... cn-

8

~ 0 0 0

0;)

~

as::

0;) 0;)

.

~

s:: 0;) 00

'4)

~

§ .,...

~

$-0

cn

~ ?"

0;)

~

cn

cn

a

0;)

"-0

..= ~

o~ cnO 0 -a

.

~-

-"(do,$-0. ~oo ~oo ~§ 0 + ~ 0 -\0

00

\0 s:: 0 0;) -'- 0 ~ 0;) 00 +- ..;j M ~ ! ~

~ ro

0 cn-cn+d..o cns::~-~O;)

~~ ~ d

.s

80cn~-0 0, s:: 0..:3 0 s:: ~° Scn 'Q.s ~ ~ 0 ~ .~ ~

~.,...

-0

0;)

oS

$s::

~

~

.9 o-,p S::t.j...j 0 Q cn-ooooO;);a ~

O;)OOS::~~ ~ s::.,...

;:::.~

$-ocnoO$-0. g, 0;) :::=

0;) 0

,,":=j

.,...

~ .,... -= m.,...

0,$-0°0-0;) p-o~$-o..o-~0, ~~oo,~o ~°.9~S~ 0 cn 0'I"'ii)0;)~~5

In -$-0

0

~ .~ ~ 5 $ !:E .g

0;)

-0

§

0;)

§

0;) In

~

0;)

~

~

'4)

0;)

0 o

-

Q

~

.,...

S::~O;)-~~ oO;)~-""'cn J -0;)

0

0;)

0;)

o

~o s:: O;).S

--c;"

~ 0'1 ~

0, 0 00 + ~ ~ P-,p cn~~\O

cn

++o-~>

.9

0 \0 + .s d 01n-~0~

0

~ >.~ cn;>~

s::s::s::cnO:::= 0 ."".""

~~~00

-,pS$-o:::=~

cn cn cn o'~

8S8S~

~

~~8~gs:: ~~~~O;)..oOO"(d 0;) 0;) 0;) 0;) ~

"""~M~cnO;)

~.o