20090266 Ver 10_GUC Dredging_USFWS BO text_20231031

GUC Raw Water Intake Maintenance Dredging
InformaƟon for USFWS Review of PotenƟal Effects to Neuse River Waterdog and
Designated CriƟcal Habitat
Proposed AcƟon
The proposed acƟon includes removal of accumulated sediment (primarily sand) and debris from
Greenville UƟliƟes Commission’s (GUC) exisƟng raw water intake structures in the Tar River. The intake
structures are located in the Tar River abuƫng the GUC Water Treatment Plant within which the raw
water is treated for distribuƟon to the City of Greenville as the sole source of drinking water. GUC has
two clusters of intake screens, and each cluster consists of four screens. The dredging area associated
with the upstream cluster of screens extends approximately 120 feet upstream and 50 feet downstream
from the screens and 80 feet from the toe of bank towards the centerline of the river (0.38 acre). The
dredging area associated with the downstream cluster extends approximately 170 feet upstream and 30
feet downstream from the screens and 75 feet from toe of bank towards the centerline of the river (0.33
acre). Figure 2-1 depicts the proposed project area.
Dredged sediments will be temporarily stockpiled and dewatered in an upland area within the water
treatment plant property. The stockpile area is presently maintained by regular mowing. Disposal of the
dredged materials will occur at an approved landfill.
The Applicant proposes the following ConservaƟon Measures in the permit applicaƟon:
1. To minimize impacts to freshwater mussels at the construcƟon site, Three Oaks Engineering
was contracted to perform mussel surveys. The surveys were conducted in September 2023.
No federally protected mussels were catalogued within the survey reach. The survey report is
aƩached to the permit applicaƟon.
2. In-water construcƟon is scheduled to be completed before the sturgeon moratorium begins on
February 1, 2024.
3. Dredging will be performed by diver-assisted hydraulic methods surrounding the intake screens
to protect the infrastructure from damage and reduce the risk of injury to aquaƟc life that may
be taking cover around the structures.
4. A turbidity curtain will be installed in the river to trap any suspended sediments and protect
against indirect impacts to downstream habitats and life associated with sedimentaƟon and
increased turbidity.
5. Temporary stockpile area will be surrounded by silt fence to prevent unintended transport of
sediment out of the stockpile area.
Other AcƟviƟes Caused by the AcƟon
The maintenance dredging will not induce development or other ac ƟviƟes to be undertaken in the
region. Anthropogenic acƟviƟes will not be increased as a result of the acƟon.
AcƟon Area
The GUC WTP is located on the north bank of the Tar River in Pi Ʃ County. The intake screen clusters are
located in the river and connect to the raw water intake pump staƟon situated on the bank of the river.
The Tar River ranges from 150 to 260 feet wide with banks ranging from 3 to 12 feet high. Water depth
was measured to be up to 15 feet in the deepest thalweg run. Substrate at the site consists primarily of
coarse sand with stable gravel and cobble in the thalweg. Woody debris was common at the Ɵme of the
mussel survey, and the water was slightly tannic. The riparian zone is characterized by maintained grassy
areas, exisƟng infrastructure, and forested areas dominated by bald cypress.
AcƟviƟes in and along the Tar River are subject to the Tar-Pamlico Riparian Buffer Rules (15A NCAC 02B
.0734), to maintain and protect exisƟng riparian buffers and their nutrient removal funcƟons. This Rule
applies to acƟviƟes conducted within 50-foot-wide riparian buffers directly adjacent to surface waters in
the Tar-Pamlico River Basin. Proposed acƟviƟes will not disturb any porƟon of the riparian buffers.
Equipment will be moved within and through previously disturbed areas within the riparian buffers.
However, no new land disturbance or vegetaƟon removal is proposed in the buffers.
Figure 2-1 shows the locaƟons and the spaƟal extents of all acƟviƟes that the proposed AcƟon would
cause reasonably certain changes to land, water, or air caused by these ac ƟviƟes, based on the
descripƟons and analyses of these acƟviƟes in this secƟon. The AcƟon Area for this BO includes those
porƟons of the Tar River within the footprint of the project, along with por Ɵons of the Tar River that are
subject to runoff from the project. The AcƟon Area includes the river channel from a point 100 meters
upstream of the proposed dredging to a point 400 meters downstream, as depicted on Figure 1 of the
aƩached Freshwater Mussel Survey Report. Under normal circumstances, a downstream distance of 400
meters is generally considered to be the extent of detectable sedimentaƟon effects.
®0 200 400100Feet
1 inch = 200 feet Greenvill e Utili ties CommissionRaw Water Intake Screen Replacement and D redgingPitt County, North Carolina
Figu re 2-1: Proposed Action
Bu ffer Zon e 2
Prop osed Project Footprint
Tar River
Prop osed Construction Laydown AreaFloodway(L andwa rd Limit)
Delin eated We tla nd
Bu ffer Zon e 1
Upstrea m IntakeScreens Cluster
Downstream IntakeScreens Cluster
Prop osed Maintenance Dredging Footprint