HomeMy WebLinkAbout19970616 Ver 1_Monitoring Report_20030915
® North Carolina Wildlife Resources Commission
Charles R. Fullwood, Executive Director
INELKS 14 i mp
MEMORANDUM 6 2003
TO: /Cynthia Van Der Wiele, NCDWQ ATER WAVY SECTION
Jean Manuele, USCOE
Lindsey Riddick, NCDOT
FROM: Joe Mickey, NCWRC Stream Mitigation Coordinator 40-- ?
DATE: September 11, 2003
SUBJECT: Carp Mitigation Site 2002 -2003 Monitoring Report
We are pleased to submit the Carp Mitigation Site monitoring report for 2002 and 2003
for your review and files. This report is submitted as partial fulfillment of the North Carolina
Department of Transportation and North Carolina Wildlife Resources mitigation agreement for
Transportation Improvement Project R-529 BA, BB, BD, US 421 in Watauga County. This
stream mitigation work was authorized under U.S. Army Corps of Engineers permit number
199707161 and N.C. Division of Water Quality permit number 970616.
If you have questions or concerns about this monitoring report, please do not hesitate to
contact me at 336/527-1547 or 1549.
Mailing Address: Division of Inland Fisheries • 1721 Mail Service Center • Raleigh, NC 27699-1721
Telephone: (919) 733-3633 ext. 281 9 Fax: (919) 715-7643
CARP MITIGATION SITE, UNNAMED TRIBUTARY TO
LAXON CREEK, WATAUGA COUNTY
Monitoring Report
Prepared for the
NORTH CAROLINA DEPARTMENT OF TRANSPORTATIN STREAM
MITIGATION PROGRAM
Transportation Improvement Project R-529 BA, BB, BD
Period Covered: April 2, 2002 - April 15, 2003
Joseph H. Mickey, Jr.
Staci S. Hining
NORTH CAROLINA WILDLIFE RESOURCES COMMISSION
Division of Inland Fisheries
Raleigh
2003
Abstract.-This report summarizes the April 2, 2002 and April 15, 2003 monitoring of 542 linear
feet of Priority I stream restoration at the Carp site on an unnamed tributary to Laxon Creek,
Watauga County. This monitoring report is submitted in partial fulfillment of the off-site stream
mitigation agreement between the North Carolina Department of Transportation (DOT) and North
Carolina Wildlife Resources Commission (WRC) for the R-529 US 421 road improvement project
in Watauga County. Project objectives at this mitigation site were to improve water quality,
aquatic habitat, riparian quality and stream stability of the unnamed tributary on the Carp property.
The primary method to achieve the above objectives was to construct a meandering C channel on a
new alignment (Priority I restoration) to reestablish proper stream dimension, pattern, and profile
through the pasture. Other enhancement activities included placement of in-stream cover,
resloping selected stream banks and revegetation of the entire reach. Monitoring surveys included
a longitudinal profile, cross-sections, modified Wolman pebble counts, reference photographs,
vegetative analysis, and temperature data collection. There has been little change in the post-
construction longitudinal profile when compared to the 2002 and 2003 profiles. The meander
pattern has remained stable and in-stream structures are functioning as designed The only
noticeable change to the cross-sections has been the formation of an inner berm bench at all cross-
sections except station 1+69. The 2002 smaller than normal D50 pebble size is probably a direct
result of the 2001-2002 drought. During this period there were few sediment flushing flows,
resulting in smaller particle sizes being present.
The purpose of this report is to summarize the April 2, 2002 and April 15, 2003 monitoring
data collected from 542 linear feet of Priority I stream restoration at the Carp site (Figure 1) on
an unnamed tributary to Laxon Creek, Watauga County. The Priority I construction of the new
channel was completed on November 2, 2000. The as-built survey was completed and submitted
to North Carolina Department of Transportation (DOT), North Carolina Division of Water
Quality (DWQ) and United States Army Corps of Engineers (COE) in May 2001 (Mickey and
Scott, 2001). This monitoring report is submitted in partial fulfillment of the off-site stream
mitigation agreement between the DOT and North Carolina Wildlife Resources Commission
(WRC) for the R-529 (US 421) road improvement project in Watuaga County. Under this
agreement, a total of 14,814 linear feet of stream mitigation is required by the United States
Army Corps of Engineers under COE 404 permit number 199707161 and 7,407 linear feet of
stream mitigation is required by DWQ 401 permit number 970616.
Drainage area at the restoration site is 448 acres (0.7 mi). The lower end of the project
begins at the tributary's confluence with Laxon Creek. The conservation easement of the site
totals 0.76 acres. The watershed contains a low density of homes with agricultural operations
being the primary land disturbing activity. Most of the hillsides and valleys are used for cattle
grazing, hay production, and Christmas tree farming. A significant portion of the watershed
remains in second growth forest. At the present time, there is some conversion of agricultural
land to single family home sites. Sediment in the stream originates mainly from livestock
pastures and gravel roads. Project objectives at this mitigation site were to improve water
quality, aquatic habitat, riparian area quality, and channel stability of the unnamed tributary on
the Carp property.
The primary method to achieve the above objectives was to construct a meandering C channel
(Rosgen 1996) on a new alignment (Priority I restoration) during October and November 2000.
This was accomplished by creation of a channel containing the proper dimension, pattern, and
profile through the adjacent pasture. Aquatic and riparian area habitats were improved by
addition of in-stream cover, reshaping of selected stream banks and revegetation of the entire
reach (Mickey and Martinez 2000). An as built survey was completed in April 2001 (Mickey
and Scott 2002) using methods described by Harrelson et al. (1994).
Methods
The DWQ and COE require annual monitoring surveys as conditions of their permits.
Monitoring surveys must document the dimension, pattern and profile of the restored channel.
No less than two bankfull flow events must be documented through the required five year
monitoring period. If less than two bankfull events occur during the first five years, monitoring
must continue until the second bankfull event is documented. The bankfull events must occur
during separate monitoring years.
Monitoring summarized in this report is based on WRC guidelines (Clemmons 2000), DWQ
and Division of Land Resources (DLR) (2002) draft guidelines and COE (2003) stream
mitigation guidelines. Monitoring data collected at this Priority I restoration includes the
following: channel morphology (stability analysis: cross-sections, longitudinal profile, and
pebble counts), reference photographs, plant survival analysis, and water temperature.
Morphology
Permanent cross-sections were established at seven locations (Mickey and Scott 2001) during
the as-built survey by placing permanent pins in the ground so points along the tape line up
exactly year to year. Cross-sections are monitored by taking measurements from left to right,
crossing through the channel and up the bank to include some floodplain measurements. All
breaks in slope are measured, within and outside the channel. If a potential problem area
develops a new cross-section will be established at this location and assessed year to year. If
instability occurs, the problem will be repaired.
The longitudinal profile of the stream channel is measured from a known point downstream to
the lowest extent of the reach. The location of features measured include the heads of riffles and
pools, water surface elevations, in-stream structures, bankfull elevation, top of bank elevation
and any other channel forming feature. Longitudinal profiles were plotted over previous year(s)
data for comparisons.
Modified Wolman pebble counts (Rosgen 1996) were conducted pre-construction as a basis
for comparison with the as-built and monitoring counts. This data is taken to assess changes in
the bed composition pre- and post-construction and during the monitoring years. One hundred
counts from pools and riffles were taken along a reach (ratio equal to that of the overall reach
pool/riffle ratio) and along a riffle cross-section.
Judgements on success or failure of restoration activities based on the data will be subjective.
It is anticipated that there will be some minor changes in the cross-sections, longitudinal profile
and substrate composition. Changes that may occur during the monitoring period will be
evaluated to determine if they represent a movement toward a more unstable condition or are
changes that represent an increase in stability.
2
Reference Photographs
Reference photograph points were located at distinguishing points along the stream.
Photographs were taken from the same location and during the same time of year to make
accurate comparisons. Photographs were used to subjectively evaluate channel aggradation or
degradation, bank erosion, success of riparian vegetation, and effectiveness of in-stream
structures. Photographs were used to indicate if excessive bank erosion or bank instability were
occurring. Where potential problem areas appear to be developing, additional photographs were
taken and a cross-section transect established. When channel or bank instability occurs, the
problem will be repaired.
Vegetation
Vegetation was monitored by direct counts over the length of the reach. Due to the short
length of the site, vegetation survival plots were not established. Numbers of live trees and
livestakes were be recorded and compared to the numbers planted.
Temperature
Temperature loggers were placed in the stream at the upper and lower ends of the project
reach. Loggers were programmed to record temperature hourly and installed in July. Data was
downloaded, edited and plotted. Twenty degrees Celsius (68°F) was chosen as the generally
accepted maximum water temperature that will sustain coldwater communities (COE 2003). The
daily mean water temperatures were calculated by averaging all the readings for that day.
Results
Morphology
Cross-sections and longitudinal profile data were collected on April 2, 2002 and April 15,
2003. Pebble count data were collected on June 13, 2002 and April 15, 2003.
Overlay of data from the seven cross-sections, as shown in Figures 2. 1-2.7, indicate few
changes have taken place in the channel with regards to the width/depth ratio, area and
entrenchment ratio. Data from the riffle cross-section at station 2+24 and run cross-section 3+76
(Table 1) show that the new channel is classified as C4 (Rosgen 1996). The only noticeable
change has been the formation of an inner berm bench at all cross-sections except station 1+69
(Figures 2. 1-2. 7).
Longitudinal profile data were collected from the 542 linear feet of restored stream.
Longitudinal profiles were overlaid to show changes in bed form from previous years (Figure 3).
The as-built survey data showed there were 44% pools in 2001 (Mickey and Scott), whereas in
2002 and 2003 pool habitat comprised 44% and 42% of the total reach. The longitudinal profile
revealed some bed aggradation at stations 0+55-1+45, 3+24-3+76 and 4+90-5+42. A debris jam
was located at station 4+35.
3
Table 2 compares the as-built (2001) pebble count data with 2002 and 2003 monitoring data.
The D50 weighted pebble size was 3.9 mm in 2002 and 15.0 mm in 2003. The D50 material is in
the high range for medium gravel. The stream is classified as a gravel bed stream, C4 (Rosgen,
1996). Appendix 2 summarizes the 2002 and 2003 pebble count raw data.
Reference Photographs
Reference photographs show a maturing riparian buffer. Photographs also show bank
stability from year to year with no development of unstable depositional areas or bank erosion
along the reach (Appendix 2).
Vegetation
Since construction, all banks have become well vegetated. Of the five hundred thirty-three
(533) live stakes and bare root nursery trees planted on the 0.67 acre site during March 2001,
November 2002, and March 2003 (Table 3), 82% of the live stakes and 31 % of the trees survived
to May 2003. Over a three-year period 363 trees were planted at the site with a 31% surviving to
2003. Combined survival for both trees and livestakes was 47%.
Temperature
Temperature was recorded hourly from July 26 - September 27, 2001 and from June 8 -
October 6, 2002 at the upper and lower ends of the project site (Appendix 3). The data indicates
that stream temperatures showed little variability in 2001, whereas stream temperatures
experienced a wider range of fluctuations in 2002. In order to better understand temperature
fluctuations at the site, 20°C (68°F) was selected as a threshold point where water temperatures
might begin to negatively impact cold water fish populations. The number of hours and days
from July 26 through September 27 were determined, then the number of hours and days that
20°C was exceeded at the upper and lower ends of the site were calculated. In 2001, the upper
end of the project had 7 hours spaced over 2 days that exceeded 20°C (0.461/6), while the lower
end of the project had 38 hours spaced over 11 days that exceeded 20°C (2.5%). In 2002, the
upper end of the project had 9 hours spaced over 2 days that exceeded 20°C (0.590/o), while the
lower end had 215 hours spaced over 36 days that exceeded 20°C (14%). For the period of July
26 to September 27, 2001 and 2002 (Figure 4), the average daily water temperatures at the upper
end of the project were 16.4°C and 17.3°C whereas the average daily water temperatures at the
lower end of the project were 16.6°C and 170C.
Discussion
Stream flows were at all time lows during 2001 and 2002 and few sediment flushing flows
occurred during this period. Bankfull events did occur on March 30, 2001 and February 22,
2002 prior to the April 2, 2002 monitoring survey. Prior to the April 15, 2003 monitoring
survey, bankfull events occurred on July 4, 2002 and March 16, 2003. As normal rain events
returned to North Carolina during fall 2002 and winter 2003 breaking the drought cycle, there
were several inner berm flow events during this time period.
4
Morphology
There has been little change in the cross-section dimensions since completion of the as-built
survey in 2001. However, in 2003, an inner berm bench began forming once the drought cycle
was broken in the fall of 2002. High stream flows began to deposit sediments on the constructed
floodplain. There has been an indication that some of the pools have become shallower,
however, this does not appear to be the result of aggradation, but the result of a shift in the pool
thalweg at the permanent cross-section location. These results do not indicate instability within
the channel.
There has been some change in the as-built longitudinal profile when compared to the 2002
and 2003 profiles. Pool habitat has remained fairly constant since the as-built survey. There has
been some aggradation of materials at some locations and some deepening at other locations;
however, none of this activity indicates a migration towards an unstable stream channel. These
changes appear to be normal stream adjustments to stream flow and weather conditions. The bed
aggradation observed at stations 0+55-1+45 appears to be a natural stream channel adjustment
since there was no construction work done at or upstream of this point. The aggradation at the
long pool/glide constructed at stations 3+24-3+76 is also the result of natural channel processes.
The aggradation at stations 4+90-5+42 is probably the direct result of existing streambed levels
taken during 2001, 2002 and 2003 at the confluence with Laxon Creek (station 5+42). There has
been no shift in the meander pattern as the stream has remained stable and in-stream structures
are functioning as designed. No bank scour or erosion was evident and no problems were noted
with any of the structures.
The 2002 smaller than normal D50 reach pebble size is probably a direct result of the 2001-
2002 drought. During this period, there were few sediment flushing flows, resulting in smaller
particle sizes being present. During reduced flows and small storm events, smaller bed materials
can be deposited throughout the site. Off-site sedimentation comes from eroding banks and
livestock access upstream of the site. The larger storm events experienced in late 2002 and
during 2003 were able to flush these smaller bed materials through the site and allow for larger
bed materials to be exposed. The 2003 D50 material compares favorably to the pre construction
and as-built pebble count sizes of 15.0 mm and 16.7 mm (Mickey and Scott, 2001).
Reference Photographs
The goal of a conservation easement around this reach of stream is to reestablish a riparian
corridor with mature vegetation. The photographs in Appendix 2 show that by restricting use of
the riparian corridor, the vegetation will grow and eventually shade the stream, decreasing
temperature and improving wildlife and aquatic habitat. The reference photographs also show
in-stream structure and channel stability throughout the reach.
Vegetation
The majority of the plantings occurred in 2001. Live stakes, collected from nearby stream
corridors, included silky dogwood Corpus amomum and silky willow Salix sericea. Bare root
trees from the N.C. Forest Service were northern red oak Quercus rubra, black cherry Prunus
serotina, persimmon Diospyros virginiana, sugarberry Celtis laevigata, white ash Frwdnus
americana, white pine Pinus strobus, tag alder Alnus serrulata, black locust Robinia
pseudoacacia L., black walnut Jugkms nigra, and eastern hemlock Tsuga canadensis (Table 3).
The lower than expected tree survival can be attributed to the drought occurring in 2001 and
2002. Also, a tall and dense ground cover of fescue and other forbes probably reduced tree
survival and could have resulted in some surviving trees being missed during the survey. The
high survival of livestakes (82%) is attributed to their being planted at the waters edge where
they were not impacted by the drought. Based on DWQ criteria of 320 stems per acre through
year three for mitigation sites, this 0.67-acre site should contain 214 trees/shrubs. Currently, 252
trees and live stakes planted at the site are surviving. During the count, tag alder, seeded
naturally, were observed at numerous locations along the new stream channel. These volunteer
tag alder will provide additional shade and stability to the channel. We will continue to monitor
plant survival to ensure that a good stand of shrubs and trees becomes established.
Temperature
The higher water temperatures in 2002 can be attributed to the low flows during the drought
of 2002 and the fact that overhanging vegetation has not become well established. As planted
vegetation matures, the amount of time water temperatures exceed 20°C should decrease. This
will make habitat conditions more favorable to cold water fish species.
Summary
Through natural stream design, a new C channel containing proper pattern, dimension and
profile has been constructed at the Carp site. The site has not experienced any failures since
construction in 2000. Water quality at the site has been improved through reduced sedimentation
from eroding banks. As the riparian zone matures, water temperatures should decrease,
improving cold-water fish habitat. In-stream habitat has increased for fish and aquatic
invertebrates through placement of in-stream structures. Both aquatic and terrestrial wildlife
species will benefit with the return of a functioning riparian corridor and stream aesthetics have
been improved. The new channel is functioning as planned.
Recommendations
Continue monitoring channel morphology, vegetation survival, and taking
photographic records for four additional years.
2. Compile and plot channel morphology (cross-sections, longitudinal profile,
and pebble count) data cumulatively and asses for indications of change
towards a more unstable or stable condition.
3. Expand site photographic records to show the site during winter and to
document any channel or vegetation changes that occur during the year.
4. Inspect the site after potential bankfull storm events to document
6
damage to the stream banks or structures.
5. Monitor potential problem areas with new cross-sections and photographs to
determine if they are migrating towards an unstable condition.
6. Repair problem areas if it is determined that they are creating unstable
channel conditions.
7
References
Clemmons, Micky. M. 2000. Mitigation site monitoring protocol for the NCWRC/NCDOT
mitigation program. North Carolina Wildlife Resources Commission, Habitat
Conservation Program, Raleigh.
Harrelson, C. C., C. L. Rawlins, and I P. Potyondy. 1994. Stream reference sites: an
illustrated guide to field technique. U. S. Department of Agriculture, Forest Service,
Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-
245, Fort Collins, Colorado.
Mickey, I H. and M. Martinez. 2000. Conceptual restoration plan (revised), Carp site,
unnamed tributary to Laxon Creek. North Carolina Wildlife Resources Commission,
Raleigh. 20 pp.
Mickey, 7, H. and S. Scott. 2001. As-built report for the Carp mitigation site, unnamed
tributary to Laxon Creek, Watauga County. North Carolina Wildlife Resources
Commission, Raleigh. 19 pp.
Rosgen, Dave L. 1996. Applied river morphology. Wildland Hydrology Books, Pagosa
Springs, Colorado.
The North Carolina Division of Land Resources and The North Carolina Division of Water
Quality. 2000. "Draft internal technical guide for stream work in North Carolina".
Raleigh.
The U. S. Army Corps of Engineers - Wilmington District, U. S. Environmental Protection
Agency, North Carolina Wildlife Resources Commission, and The NC Division of Water
Quality. 2003. "Stream mitigation guidelines". 26 pp.
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FIGURE 2.1. Cross-section station 1+69, stair step pool.
FIGURE 2. Seven post-construction and monitoring cross-sections for the Carp
mitigation site, uimamed tributary to Laxon Creek, Watauga County, 2001-2003.
FIGURE 2.2. Cross-section station 1+94, pool.
FIGURE 2. Continued.
FIGURE 2.4. Cross-section station 2+45, pool.
FIGURE 2.5. Cross-section station 2+79, step pool.
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TABLE 2. Pebble count data collected in millimeters from the unnamed tributary to Laxon
Creek, Carp mitigation site, Watauga County, 2001-2003.
l:rncc-sectinn at 2+24 (riffle)
----- Year 2001a 2002 2003
D 16 5.6 1.5
D 50 21.5 10.5 16.5
D 84 56 36 55
Reach 40% ools/600 riffles
Year 2001 2002 2003
D 16 0.10 0.56
D 50 14.3 0.3 13.7
D 84 32 14 42
Wei ghted°
Date 2001 2002 2003
D 16 0.25 N/A 0.96
D 50 16.7 3.9 15
D 84 43 26 50
a 2001 as-built survey
b Millimeter size
Combined riffle and reach pebble count data
TABLE 3.-Survival of live stakes and trees planted at the Carp mitigation site, unnamed
tributary to Laxon Creek, Watauga County, 2001-2003.
Number Number
Planted February and March 2001 planted survivinga
White Pine 40 10
Black cherry 50 28
N. Red oak 50 16
Persimmon 65 0
White ashe 65 1
Silky dogwood live stakes 94 56
Silky willow live stakes 77 85
441 196 (44% survival)
Planted November 2002
Tag alders
Black walnut
Dogwood
Planted March 2003
Persimmon
Black locust
Sugarberry
Black walnut
Red oak
Hemlock (planted May 2003)
35 20
5 2
15 8
55 30 (55% survival)
7 0
8 7
5 5
7 7
7 4
3 3
37 26 (70% survival)
Total (trees and live stakes)
533 252 (471/o survival)b
'Counted on May 14, 2003.
bStem survival required by DWQ at this 0.67 acre site after 3 years is 214 and after 5 years is
174.
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