20201125 Ver 2_Cashiers WWTP - Qualitative Indirect and Cumulative Impact Analysis_20220303

Shaping
Communities
Together
October 15, 2020
Tuckaseigee Water and Sewer Authority
Horsepasture River WWTP and Collection System Improvements
Qualitative Indirect and Cumulative Impact Analysis
JacksonCounty, North Carolina
Growth is likely to be induced within the Horsepasture River watershed by the
proposed Horsepasture River Wastewater Treatment Plant (WWTP)and Collection
System Improvements project. The purpose of the proposed project is to provide
additional wastewater treatment capacity in the Cashiers, NCarea. Futuregrowth
in the surrounding area is expected to follow the existing pattern of primarily
commercialand both low and high density residential. Existing development,
planning regulations, and proposedprojects wereconsidered in sizing future
wastewater collection and treatment facilitiesto meet the needs of the growing
community.
No cumulative effects are anticipated for groundwater resources as a result of the
proposedproject. Reduction of the public water supply is not anticipated from future
domesticconsumption and commercial usage.Cumulative impacts to surface
waters within the watershed may include sedimentation and run off from land
clearing activitiesand stream and wetland crossingsassociated with new
development, however, these impacts should be mitigated by utilizing best
management practices and limiting ground disturbance to the minimum practical.
All futureimpacts to surface waters and stormwater for construction of potential
projectsshouldbepermitted through proper State and Federal Agencies. Any
increased stream sedimentation andsoil erosion from increased land clearing for
future development should also be regulated throughState and Federal permitting
processes. Changes in hydrological regimes of streams and rivers within the
watershed isnot anticipated. The treatment process for the newwastewater
treatment plant will be an advanced tertiary treatment process intended to meetthe
stringent effluent limitations of the National Pollutant Discharge Elimination System
(NPDES)permit.WWTP discharges to the Horsepasture River will be closely
monitored and abide byState and Federal water quality parametersand are not
anticipated to impact downstream water quality.
The Horsepasture River along the proposed project area is classified by the North
Carolina Department of Environmental Quality (NCDEQ)as C;Tr:+. Class C waters
are protected for uses such assecondary recreation, fishing, wildlife, fish
consumption, aquatic life including propagation, survival and maintenance of
biological integrity, and agriculture. Secondary recreation includes wading, boating,
and other uses involving human body contact with water where such activities take
place in an infrequent, unorganized, or incidental manner.Trout Waters (Tr)is a
supplemental classification intended to protect freshwaters which have conditions
which shall sustain and allow for trout propagation and survival of stocked trout on
a year-round basis. This classification is not the same as the NC Wildlife Resources
Commission's Designated Public Mountain Trout Waters designation.The +symbol
MCGILL ASSOCIATES 1013 STATE FARM ROAD, BOONE, NC 28607 /828.386.1920 /MCGILLASSOCIATES.COM

Horsepasture River WWTP and Collection System Improvements
Qualitative Indirect and Cumulative Impact Analysis
Page 2of 2
identifies waters that are subject to a specialmanagement strategy specified in 15A
NCAC 2B .0225 the Outstanding Resource Waters (ORW) rule.All outstanding
resource waters are a subset of High Quality Waters. This supplemental
classification is intended to protect unique and special waters having excellent water
quality and being of exceptional state or national ecological or recreational
significance.Per the ORW rule, water quality conditions shall be maintained to
protect the outstanding resource values of all undesignated waterbodies that are
located within the Horsepasture River watershed. No new discharges or expansions
of existing discharges shall be permitted, and stormwater controls for all new
development activities requiring an Erosion and Sedimentation Control Plan in
accordance with rulesestablished by the NC Sedimentation Control Commission
shall comply with the stormwater provisions set forth in 15A NCAC 02H .1000,
including the specific stormwater management requirements for freshwater ORW
areas set forth in 15A NCAC 02H .1019 and .1021.However, new domestic
wastewater discharges and expansions of existing wastewater discharges shall be
allowed provided that: (A) Oxygen Consuming Wastes: Effluent limitations shall be
as follows: BOD shall not exceed 5 mg/l and NH3-N shall not exceed 2 mg/l; (B)
Total Suspended Solids: Discharges of total suspended solids (TSS) shall be limited
to effluent concentrations of 10 mg/1 for trout waters and to 20 mg/l for all other
waters except for mining operations, which shall be held to their respective NPDES
TSS permit limits.(C) Nutrients: If nutrient overenrichment is projected to be a
concern, effluent limitations shall be set for phosphorus, nitrogen, or both; and (D)
Volume: The total volume of treated wastewater for all discharges combined shall
not exceed 25 percent of the total instream flow in the designated ORW under 7Q10
conditions.
The NPDES limitations, existing ORW rules, and the required Erosion and
Sedimentation Control Plan in accordance with rules established by the NC
Sedimentation Control Commissionshould reduce or eliminate the need for
additional regulatory measures. Strict adherence to these regulatory programs
should result in the protection of the watershed during growth in the surrounding
area.
Please provide any comments regarding concerns or other issues of significance
that may affect this project. We look forward to your comments on this matter. If you
have any questions, feel free to contact me at our office phone number of (828)
386-1920 or my email address [e-mail].
MCGILL ASSOCIATES 1013 STATE FARM ROAD, BOONE, NC 28607 /828.386.1920 /MCGILLASSOCIATES.COM