20160849 Ver 1_MP_FINAL_IRT Response Letter_20200227

February 28, 2020
US Army Corps of Engineers
Charlotte Regulatory Field Office
Attn: Bryan Roden-Reynolds
8430 University Executive Park Drive
Charlotte, NC 28262

RE: WLS Responses to NCIRT Review Comments Regarding the Upper Rocky Umbrella Mitigation
Bank (UMBI) Final Mitigation Plan Approval for the Upper Rocky Mitigation Project, USACE AID#
SAW-2015-01816, Yadkin River Basin, Cataloging Unit 03040105, Mecklenburg County, NC Dear Mr. Roden-Reynolds: Water & Land Solutions, LLC (WLS) is pleased to provide our written responses to the North Carolina Interagency Review Team (NCIRT) review comments dated January 23, 2020 regarding the Draft Mitigation Plan for the Upper Rocky Mitigation Project. We are providing our written responses to the NCIRT’s review comments below, which includes editing and updating the Final Mitigation Plan and associated deliverables accordingly. Each of the NCIRT review comments is copied below in bold text, followed by the appropriate response from WLS in regular text:
USACE Comments (Kim Browning):

General Comments
1. The labels, colors and reach names used in this draft mitigation plan are completely different
than those used during the prospectus stage. Please use consistent labeling throughout the life of
the project. Response: WLS understands the importance of this concern and has made every effort to adhere to this on recent projects. The Upper Rocky prospectus was submitted in 2016 and the labeling/colors were updated for the June 2019 IRT site visit and JD submittal to follow current IRT guidance.

2. (Wetland re-establishment): Please incorporate similar language as used in the Scarborough
response letter regarding the inclusion of coarse woody debris throughout the wetlands for
habitat, and to help store sediment, increase water storage/infiltration, and absorb water energy
during overbank events. “These features will mimic small floodplain pools which include CWD
within the wetland areas that will provide habitat structure and complexity across the Project.
We have added language in these sections describing examples of CWD such as tree throws,
snags, and stumps and included general locations/distribution on the design plan sheets.” Response: Similar language regarding coarse woody debris has been added to the Final Mitigation Plan. WLS appreciates this comment and agrees that coarse woody debris (CWD) serves an important functional role when restoring stream and wetland systems as described in Sections 6.2.4 and 6.6.2. These features will mimic small floodplain pools which include CWD within the wetland areas that will provide habitat structure and complexity across the Project. We have added language in these sections
describing examples of CWD such as tree throws, snags, and stumps and included general locations/distribution on the design plan sheets.

3. The Umbrella Mitigation Banking Instrument (UMBI): The Corps representatives are Scott
McClendon and Bryan Roden-Reynolds. Response: The UMBI has been updated to list Scott McLendon and Bryan Roden-Reynolds for the USACE.

4. There is extensive earthwork required on this site which will likely result in overly deep
floodplain pools. The inclusion of vernal pools is acceptable, and should be 8-14” depressions
that dry up annually so that predatory species cannot colonize. Response: WLS agrees with this comment and the vernal pools/floodplain depressions will not exceed 8-14” deep as suggested. We have revised our channel plug detail to reflect this intent. Annotations within the design plan sheets will further emphasize the size and depth of the floodplain depressional feature to prevent overly deep pools resulting in stagnant water conditions.

5. For Reach R2, please show the existing road right-of-way boundary line. Recommend a 50-ft
setback of the proposed easement from the existing road edge to avoid potential future
transportation/culvert easement encroachment requests. This also applies to the proposed
greenway that bisects this reach. Response: WLS has revised the design plan sheets to illustrate the Doves Crest road right-of-way (ROW). The conservation easement deed on this portion of the project was completed in December 2016. WLS is not proposing any stream mitigation credit along upper R2 even though it is within a conservation easement and Enhancement Level I stream work is proposed along this section. The ROW is 50 feet wide and the easement in this section is 13.26 ft from the edge of the road. The lower portion of R2 already also accounts for the 50-ft ROW, but is also setback 46.1 ft from the existing road edge. The greenway corridor will be removed from the conservation easement area once it is constructed and surveyed. The proposed greenway trail is 10-ft wide with a 5-ft shoulder on each side, but the greenway trail area to be removed from the conservation easement will be 30-ft wide or 15-ft on each side of the greenway trail centerline. This is what the Town of Cornelius has required for the greenway construction and maintenance.

6. Reach R3 should be connected with Reach R6 near the bottom of the beaver dam, or into the
beaver area, and not parallel in the floodplain. Response: This concern was discussed and addressed during the June 2019 IRT site visit by examining the existing valley topography, flow paths and crenulations in the field. The IRT preferred that the stream design approach did not disturb the lower beaver dam system. WLS intentionally designed reaches R3 and R6 as shown on the design plans not to unnecessarily increase stream length/credits, but to mimic current stream/valley alignments and natural floodplain connections. The existing channel alignments and valley crenulations show R3 and R6 tying in near the proposed design channels. It is WLS’s intent to not change watershed hydraulics/hydrology by conveying current and future flood flows competently and without adverse effects to channel and floodplain conditions, and to allow for increased habitat and bedform diversity within the appropriately sized bankfull channels. Furthermore, maintaining stream flows within a single channel farther up in the valley will likely increase concentrated flows, excess scour potential and stream degradation given the urbanizing watershed. The flood model validates this approach by allowing flood flows to spread out across the activated floodplain which will ultimately reduce in-stream erosion.

7. The proposed easement should not include the area where the proposed greenway will be
located. Please adjust the easement boundary, especially where W4 is located. This area will be
functionally compromised due to fragmentation and should not be included for credit.
Additionally, please confirm the construction easements for the greenway and adjust the
easement accordingly to prevent future encroachments. The slopes along the stream where the
greenway is proposed will likely require some cut-fill to get a level trail, which would likely
require more space. Response: As previously mentioned in response comment #5, this portion of the project is already in a conservation easement and the easement boundary cannot be altered. The greenway corridor will be 30-ft wide and removed from the easement area (10-ft wide trail, 5-ft shoulder on each side, and additional 5-ft on each side for maintenance; or 15ft from center on each side of greenway). The aggregate base course will be installed for the future greenway during the stream construction. Once the greenway is constructed and surveyed, the greenway corridor (30-ft wide area) will be removed from the conservation easement per the conservation easement deed and released to the Town of Cornelius. Only a small portion of proposed wetlands will be impacted due to the greenway. W4 is the small jurisdictional wetland in pink and is not adjacent to the greenway nor will the greenway impact this wetland, but WLS will still remove W4 as creditable wetland acreage. The greenway will be constructed through proposed wetlands and not existing wetlands. The section of W4 that is bisected by the sewer line easement and the greenway will be removed from creditable proposed wetland acreage.

8. Is the purpose for the easement break that bisects W5 a sewer line? As proposed, this area will
also be functionally compromised due to fragmentation and should be removed from the
easement. Response: Yes, W5 is bisected by an existing sewer line easement and this conservation easement is already finalized. W5 is a jurisdictional wetland is still hydrologically connected with the sewer line that is currently in place (not a proposed line, it is active). W5 is a toe of slope wetland along the floodplain and is not affected by the stream restoration or sewer line easement. WLS proposes to leave W5 as wetland preservation credit.

9. During the IRT site walk, appropriate approaches for R5 were discussed. Restoration should
not be proposed for the entirety of R5 as shown. The middle section should be preservation
based on current conditions. Assuming this is the EII section, please justify the need for
enhancement rather than preservation. Response: The proposed design of R5 includes both Restoration and Enhancement Level II approaches. Based on the IRT site visit, WLS intentionally split R5 into Restoration and Enhancement Level II approaches at locations shown on the design plans. Enhancement Level II sections of this reach will be supplementally planted and Restoration of R5 above and below these sections will provide additional functional uplift for the stream and adjacent wetland hydrology to justify an Enhancement Level II approach.

10. There are concerns about how you will manage beaver on some portions of the site, while
allowing beaver to remain in the wetlands on other portions of the site. Please discuss the
feasibility. Response: Per discussions during the IRT site visit, the existing beaver dam complex located along wetland area W6 is currently stable and providing a water quality benefit. It was noted that there is only one active dam present in the upper valley below reach R7. The beaver activity, including foraging and movement patterns will be closely monitored by WLS throughout each year. WLS will document any high risk areas and beaver colonies beyond W6 will be maintained within the Project boundary to prevent future dam development and impacts to stream hydrology, site drainage and riparian buffer vegetation planted within restored stream reaches. Routine maintenance and repair activities caused by beaver activity may include supplemental planting, pruning, and dewatering/dam removal. Beaver management be implemented using accepted trapping and removal methods within the recorded Conservation Easement.

Draft Plan Specific Section Comments

1. In Section 1.1, please provide the conservation easement acreage. Response: The easement acreage has been added to Section 1.1.

2. Section 1.3, states that “site protection through a 44.2-acre easement, while the UP2S
calculation is for a 43 acre easement.” Please clarify. Response: The UP2S calculation was from August 2019 and based on the proposed easement at that time. At the time of the draft mitigation plan submittal the acreage was 44.2 acres. The easement boundaries are being finalized and in a preliminary plat stage and that total acreage is 43.74 acres. The endowment breakdown document has been updated with this acreage.

3. In Section 3.1.4, please provide a summary or table to show the North Carolina Stream
Assessment Methodology/North Carolina Wetland Assessment Methodology (NCSAM)/(NCWAM)
current functional assessment results. Response: A summary table of the results of NCSAM/NCWAM has been added to section 3.1.4 of the mitigation plan.

4. In Section 3.7, beavers should be discussed as a potential site constraint. Response: Added subsection 3.7.7, pg 25 that discusses beaver activity as a potential site constraint to restored stream reaches and planted riparian buffer vegetation.

5. Within Table 7 (Proposed Stream Mitigation Credits), the ratio for R5 should be 2.5:1.
Therefore, please revise Table 7. Response: This is now Table 8 and R5 is broken up into both Restoration and Enhancement Level II sections. There is a row for each mitigation type and the Enhancement Level II section ratio is 2.5:1.

6. In Section 5, are you seeking the additional 2% credit for water quality monitoring and benthic
monitoring? If so, please specify in this section and add a column in Table 7 to show how the
additional credits are calculated. Response: WLS is not seeking additional 2% credit for water quality and benthic monitoring.

7. In Section 5.2 (Credit Release Schedule), do you anticipate receiving all of the wetland
preservation credits with the first 15% credit release? If so, please specify in Table 9. Response: Yes, WLS anticipates receiving all of the wetland preservation credits in the initial release. Table 10 has been updated to reflect this.

8. In Section 6.2.1, please clarify what work will be done when discussing “Enhancement Level II
practices.” Response: WLS updated section 6.2.1 to clarify work being performed in the Enhancement Level II sections, which includes supplementally planting the riparian buffer, stabilizing any eroding stream banks, and adding in-stream structures to increase bedform diversity.

9. Section 6.2.3, states planting completion at the end of May which would put the 180-day
vegetation monitoring in late November. However, monitoring should not be performed after
leaf drop. Planting beyond March 15th is not recommended and may result in an extended
monitoring period being required. Additionally, bare-root seedlings are significantly more prone
to root shock if not planted in the dormant season. Container trees/shrubs can handle the
transition better and so planting in April should yield higher survival rates. Therefore, revisions
to the planting schedule may be needed. Response: WLS understands that the IRT prefers that bare-root trees be planted between November to March. The IRT guidance also requires that vegetation and plots must be established 180 days prior to initiation of the first year of monitoring, which could allow planting in May. WLS will do their best to plant trees between November to March and anticipates planting this site in March. If WLS plants in April or May container shrubs will be considered, and we
understand that the IRT will review closely the survivability of the trees and reduced survivability could result in an additional year of vegetative monitoring.

10. In Section 8.1 (Stream Hydrology), the wording in this section is confusing. Suggest rewording
to something similar to this: Four bankfull flow events must be documented within the seven-
year monitoring period. The bankfull events must occur in separate years. Otherwise, the stream
monitoring will continue until four bankfull events have been documented in separate years. Response: Section 8.1 has been reworded to the language above to avoid confusion.

11. In Section 8.1, The Corps suggest adding a performance standard regarding Visual
Inspections or Digital Image Stations. These could be used to subjectively evaluate channel
aggradation or degradation, bank erosion, riparian vegetation success, and beaver activity. A
series of images over time should indicate successional maturation of the riparian vegetation.
Images should indicate the absence of mid-channel bars or excessive erosion. Response: A performance standard has been added to 8.1 for Photo Documentation. Section 9, Monitoring Plan, already had 9.4 Visual Assessment Monitoring that incorporates this suggestion.

12. Section 8.1 stated several areas were noted to contain extensive privet, autumn olive and
kudzu. The Corps recommends a performance standard be added that addresses invasive control
with levels no more than 5%, and no tolerance for kudzu. This will need to be maintained offsite
as well. In addition, please add kudzu to the Invasive Species on page 13 (Invasive Species
Vegetation). Response: Section 3.7.6 states that there are areas with invasive species, mainly Chinese privet and some kudzu on the project periphery. Kudzu has been added to the invasive species on page 13. A performance standard has been added, 8.4 Invasive Species, that states WLS will treat invasive species within in the project area and it will be treated/removed so that the invasive species composition is no more than 5% of the total riparian buffer area. A zero tolerance for kudzu is not feasible as maintenance of kudzu offsite will not be possible because WLS does not have permission to work outside of the easement. WLS recommends including kudzu in the 5% tolerance level for invasive species. Areas of kudzu within the easement will be treated/removed and areas of kudzu that are near the easement boundary will be monitored especially closely to ensure that re-colonization does not occur.

13. For Section 8.2, The Corps suggest restating that your hydrology standard will be at least 12%,
rather than 10-12% because as it reads, you may not be meeting performance standards if you
exceed 12%. Response: Section 8.2 has been revised to state the wetland hydrology standard will be at least 12%. The soil series is mapped as Monacan and the expected hydroperiod range is at least 10-12%. As described in Sections 6.2.4 and 6.4.2, the nearby Monteith Park mitigation park site was recently closed out in Spring 2019 by the USACE/IRT and involved the same soil type and restoration approaches. The hydroperiod at that site was at least 12% in the floodplains, but on the fringe wetlands it was ~9% consistently (see Appendix B). WLS has added to Section 11 Adaptive Management that “WLS proposes to revisit the wetland hydrology success based on early monitoring data and additional soils investigations/modeling if needed.”

14. Regarding the additional anticipated wetlands along R5 (in Section 8.2 Wetlands), do you
have well data to show the pre-data? We recommend installing groundwater gauges now, prior
to construction, in order to establish baseline data. Please revise the monitoring map to include
the location(s) of the pre-construction/baseline monitoring wells. Response: There are pre-construction gauges (wells 12-14) located on R5. All existing/pre-construction gauges have been added to Figure 8 Channel Stability & Pre-Monitoring Features. The well graphs and locations of pre-construction gauges can also be found in Appendix B.

15. In reference to Stream Monitoring (Section 9.1.1), the IRT prefers the use of pressure
transducers, rather than crest gages. Therefore, please update the mitigation plan accordingly. Response: Language has been added to this section stating that WLS will use pressure transducers and photography for documenting overbank flows and floodplain access within the monitoring period. Figure 11 shows the proposed locations of these monitoring devices.

16. The third paragraph of Section 9.3 (Vegetation Monitoring) states: “Volunteer species will be
noted and their inclusion in quadrant data will be evaluated with IRT on a case-by case basis.”
Please note that volunteer species will only be counted towards success if they are on the
approved planting list. Response: Revised language in Section 9.3 states “Volunteer species will be noted and if they are on the approved planting list and meet success criteria standards, they will be counted towards success criteria. Other species not included on the list may be considered by the IRT on a case-by-case basis.”

17. Within Table 19 (Proposed Monitoring Plan Summary), the hydrology performance standard
of 30-days only applies to intermittent streams. In addition, the hydraulics performance
standard should specify BHR that does not exceed 1.2. Therefore, please revise Table 19
accordingly. Response: Intermittent streams has been added to the hydrology performance standard in this table. Also, the BHR has been revised to not exceed 1.2.

18. In Section 10, the Corps appreciate the inclusion of the UP2S engagement letter and
corresponding cost spreadsheet. The Corps recommends to add a line-item for signage as it
would be beneficial to the mitigation plan. Response: The endowment breakdown sheet has been revised to incorporate a line-item for signage.

19. Please provide an itemized list of monitoring tasks/costs to demonstrate how you estimated
the amount for the monitoring financial assurances. This information would be added to Section
12 (Financial Assurances). Response: An itemized list of monitoring tasks/costs has been provided below Table 21 in Section 12. The monitoring financial assurance is for monitoring and maintenance and those costs are included as well in Table 21.

20. Depicted on Design Sheets 9, 10, 11…, several “floodplain pools” are shown on the design
sheets in the location of the existing channel. There is concern that there are so many, they run
parallel with the proposed channel, and the depth is not clear. Are these intended to be vernal
pools? There is no typical for these included in the Details section. These pools are in areas that
are supposed to be planted riparian buffer. The Corps has concern that there will be a lot of open
water, deeper than vernal pools, in areas that should contain vegetation. Response: WLS intends to construct vernal pools/floodplain depressions no more than 8-14” deep as suggested. We have revised our channel plug detail to reflect the design intent of the vernal pools/floodplain depressions. Annotations within the plan and profile sheets will further emphasize the size and depth of the floodplain depressions to not make the features overly deep resulting in stagnant water conditions. The depressional areas were designed to offset channel fill volumes and the quantity of them should not compromise the buffer composition, surface hydrology and overall project success.

DWR (Mac Haupt):

1. DWR likes the fact that water quality sampling will be taking place on this project as stated in
Section 3.4 (Aquatic Resource Health and Function). Response: WLS appreciates this comment as we believe that the WQ sampling will help us determine the associated functional lift that may be achieved considering site constraints and existing conditions.

2. Within Table 3 (Reach Watershed Drainage and Jurisdictional Status for Project Reaches),
DWR is concerned with the drainage sizes of some of the proposed reaches, particularly R5a and
R8. DWR likes the fact that flow gauges are being placed on these reaches. R2 and R7a are other
reaches to watch and perhaps monitor the flow. Response: WLS notes your concern and will closely monitor the flows in R5a and R8 as described in the monitoring section. Given our stream assessments performed in the field, as well as seasonal flow observations over the past the three years, we are confident that jurisdictional status will not be negatively impacted after implementing the proposed design approaches. The drainage areas and geomorphic characteristics of R2 and R7a are similar to monitored streams R8 and R5a and R7a scored as a perennial stream. In addition, we are not proposing any stream credit in the upper part of reach R2 (south of Doves Crest Rd), but will be completing Enhancement Level I treatment on this section. The proposed stream crediting begins on R2 below the Doves Crest Road ROW and WLS suggests that additional flow gauges are not necessary for these reaches.

3. In Section 3.6.3, DWR likes the extensive soil work done on the property, however, DWR does
not typically endorse the usage of the non-intentional erosional deposition for claiming historic
hydric soils. There are numerous areas in the piedmont which may have been wetlands 100-150
years ago, but with the cropping techniques of the times, mid 1800s thru early 1900s, resulted in
buried wetlands (see Stanley Trimble, 1974 and 2008). In cases where the deposition is more
recent and not as deep, DWR may consider the removal of the deposition, if there is a
documented hydric soil profile (i.e., not just indicators, but a series profile) below the deposition. Response: WLS appreciates this comment and historical reference as it relates to buried hydric soils. As described in the detailed hydric soils study, the site work included an atypical soils evaluation that confirmed legacy sediments over a historically extensive wetland soil. The site is located within an appropriate landscape and geomorphic position for a natural occurring riparian wetland system. Also, the soil work provides evidence of at least one other historic depositional event resulting in areas greater than 12 inches of deposition where hydric indicators reformed within this appropriate landscape. It is generally accepted that the more recent legacy sediment layering is anthropogenic from the mid-1800s to circa 1920 as a result of farming practices on surrounding uplands (Trimble 2008). Attempting to map or specifically define these legacy sediments to a series is not practicable in this setting due to variability across the site. Individual soil profiles fall within the accepted range for a ‘Monacan’ or ‘Wehadkee’, while other nearby profiles will fail to meet either the series or anticipated inclusion. The site-specific soil observations indicate that some areas are slowing redeveloping hydric characteristics that would be expected within this landscape position. The proposed restoration approaches will allow for the re-establishment of a former wetland that has been buried due to past cropping practices. The EPA defines Creation as, “…the "construction of a wetland in an area that was not a wetland in the recent past (within the last 100-200 years) and that is isolated from existing wetlands (i.e., not directly adjacent)" (Gwin, et al., 1999).” https://www.epa.gov/wetlands/wetlands-
restoration-definitions-and-distinctions. The proposed restoration at this site does not meet the definition of creation due to the documented historic wetlands and its connection to existing jurisdictional wetlands. Although the upland erosion rate has slowed, these legacy sediments are still present within the system and are being mobilized by the widespread stream incision. The stream restoration approach (Priority Level I) will be raising the local groundwater and re-establishing the natural processes and hydrologic conditions that have already begun to stabilize these sediments.

4. Section 3.7.3, discusses areas where the proposed greenway is within the easement; DWR
would like to see a buffer width analysis to see what the affect it would have on the stream credit. Response: WLS has run the buffer width analysis and the adjusted stream credits can be found in Table 8. Figures 13a and 13b also show the buffer widths.

5. Within Table 11 (Proposed Riparian Buffer Bare Root and Live Stake Plantings), please limit
the planting of Green Ash to no more than 5% due to the emerald ash borer. Response: Table 12 has been revised to limit green ash to 4%.

6. In Section 8.2, DWR believes the wetland performance criteria should be 12%. First, we
appreciate the fact that not only did you include pre-construction data but you included data
from the Monteith project. Some of the data from certain gauges is surprising given our
impressions from the site visit, most notably Gauges 8-11. Only Gauge 8 showed wetland
hydrology, while the area where all these gauges looked jurisdictional. In addition, the gauge
data at Monteith, while somewhat inconsistent showed significantly wet hydroperiods. Lastly,
given the fact that so many streams will be raised in the areas of proposed wetlands, DWR
believes there will be ample hydrology to sustain at least a 12% hydroperiod Response: Section 8.2 has been revised to state the wetland hydrology standard will be at least 12%. The soil series is mapped as Monacan and the expected hydroperiod range is at least 10-12%. As described in Sections 6.2.4 and 6.4.2, the nearby Monteith Park mitigation park site was recently closed out in Spring 2019 by the USACE/IRT and involved the same soil type and restoration approaches. The hydroperiod at that site was at least 12% in the floodplains, but on the fringe wetlands it was ~9% consistently (see Appendix B). WLS has added to Section 11 Adaptive Management that “WLS proposes to revisit the wetland hydrology success based on early monitoring data and additional soils investigations/modeling if needed.” WLS is also excited to have multiple years of pre-construction data. Gauge 8 is on the fringe of a jurisdictional wetland, while gauges 9-11 are not in a jurisdictional wetland.

7. Within Table 19 (Proposed Monitoring Plan Summary), the flow standard of 30 days is only
applicable to intermittent streams. Therefore, please revise Table 19 accordingly. Response: Table 20 has been revised per USACE Comment #19 also.

8. The Adaptive Management Plan (Section 11) should include some specific details/narrative for
the management of beavers, since beavers are already located within the project easement.
Therefore, please update the Adaptive Management Plan accordingly. Response: The Adaptive Management Plan has been updated to state that in W6 all beaver dams will remain in place and no beaver removal treatment is proposed for this area. All areas outside of W6 in the project area will receive routine beaver maintenance. Routine maintenance and repair activities caused by beaver activity may include supplemental planting, pruning, and dewatering/dam removal. Beaver management will be implemented using accepted trapping and removal methods only within the recorded Conservation Easement. W6 will not be maintained for beaver unless further stream reach impacts are documented above or below the existing dams.

9. Depicted on Design Sheet 3, the stream banks for the riffle typicals are steep. DWR
recommends a flatter slope for these stream banks. Response: The 2(H):1(V) - 3(H):1(V) riffle side slopes and width-to-depth (WD) ratios shown on design sheet 3 are within a common stable range of Rosgen C4 and B4 stream types. The basis for the design criteria were developed by comparing local reference reach surveys and successfully completed projects in the same physiographic region and adjacent watersheds. In general, riffle side slopes should be no steeper than 2:1 (average range from 2:1 to 3:1) for the channel banks, and a WD design ratio between 12-18 is appropriate for most small channel designs in order to adequately transport its sediment load. The typical section illustrations have been modified to represent more proportional dimensions.

10. DWR believes that R3 should not run parallel for over 500 linear feet to other streams as
designed, as depicted on Design Sheets 9 and 10. On Figure 2 (USGS Map), shows R3 connecting
much farther upstream. In addition, Figure 4 (LiDAR Map) show a flat floodplain where R3 is
likely to connect to R6. DWR believes the confluence would be at either station 17+00 or the next
constructed riffle just before the confluence with R4. Response: Please see USACE response comment #6. This concern was discussed and addressed during the June 2019 IRT site visit by examining the existing valley topography, flow paths and crenulations in the field. The IRT preferred that the stream design approach did not disturb the lower beaver dam system. WLS intentionally designed reaches R3 and R6 as shown on the design plans not to unnecessarily increase stream length/credits, but to mimic current stream/valley alignments and natural floodplain connections. The existing channel alignments and valley crenulations show R3 and R6 tying in near the proposed design channels. It is WLS’s intent to not change watershed hydraulics/hydrology by conveying current and future flood flows competently and without adverse effects to channel and floodplain conditions, and to allow for increased habitat and bedform diversity within the appropriately sized bankfull channels. Furthermore, maintaining stream flows within a single channel farther up in the valley will likely increase concentrated flows, excess scour potential and stream degradation given the urbanizing watershed. The flood model validates this approach by allowing flood flows to spread out across the activated floodplain which will ultimately reduce in-stream erosion.

11. As depicted on Design Sheets 11 and 12, the greenway will likely impact a significant amount
of wetlands and riparian buffer. Response: The future greenway alignment was field located with the intent to impact the least amount of canopy trees and existing wetland areas as possible. The greenway will be located as far from the proposed stream as possible and will match the existing topography. The design sheets distinguish between existing wetlands and proposed wetlands (difference in shading), and only a small portion of proposed wetlands would be impacted due to the proposed greenway alignment, but the proposed wetlands in the greenway location have been removed from this project. In general, the future greenway will not be constructed through any existing wetlands; in the draft mitigation plan there were proposed wetlands in part of the greenway path, but those have been removed. W4 is the small jurisdictional wetland in pink and is not adjacent to the greenway, but WLS will still remove W4 as creditable wetland acreage. The section of W7 in the draft mitigation plan that is bisected by the sewer line easement and the greenway has been removed from creditable proposed wetland acreage.

12. Depicted on Design Sheets 19-20, it appears that R3 is labeled as R1. Please correct or clarify. Response: WLS has revised design sheets 19 and 20 with the appropriate reach labels.

13. DWR would like a stream gauge placed at station 16+50 (see Design Sheet 23). Response: A flow gauge was placed at station 16+50.

14. Overall comment on Design Sheets: The edge of the cut fill slopes occur at the edge (10-15
feet) of many meander bends. DWR is concerned with the amount of floodplain access at these
meander bend edges. Response: The proposed design channels for all reaches have a minimum entrenchment ratio of 2.2. Revisions to the grading plan and cut/fill lines have been added in many areas to reflect higher entrenchment ratios (> 2.2) where appropriate and feasible.

15. Overall comment on Design Sheets: On Design Sheet 2, you labeled the legend icon as water
quality treatment feature, while it appears throughout the design sheets they are labeled as
floodplain pools. The IRT considers floodplain pools to have specific construction depths (that
allow them to dry out), while water quality treatment features may not. The typical is labeled as
a water quality treatment feature. DWR hopes that each feature does not have a 4 foot wide rip-
rap outlet as shown. Please clarify. Response: WLS has revised the hatching on the water quality treatment features to differentiate between floodplain depressions/vernal pools and water quality features. These symbols have also been updated/added to sheet 2 for further clarification. The
floodplain depressions will not have 4 ft wide rip rap outlets. These design features are only applicable to the water quality treatment features for stabilizing the outlet channel(s). Rip rap outlets are required for the water quality treatment features to maintain the design treatment volume within the structure. They also serve to deter erosion and headcutting of the outlet thereby helping to maintain the features structural integrity. Please contact me if you have any additional questions or comments. Sincerely,
Water & Land Solutions, LLC
Kayne M. Van Stell Vice President, Ecosystem Design Services Water and Land Solutions, LLC 7721 Six Forks Road, Suite 130 Raleigh, NC 27615 Office Phone: [phone] Mobile Phone: [phone] Email: [e-mail]