20191760 Ver 1_C-5621 Response to DWR_20200420_20200420 (2)

C-5621 Response to DWQ Letter dated 3/31/20
Avoidance and Minimization of stream impacts at Sites 2A and 3 at the southern roundabout:
The location of the southern roundabout had several constraints as identified below resulting in the
current location as shown. The southern roundabout is acting as a U-turn for vehicles traveling eastbound
on Catawba Avenue desiring to turn left at the Catawba Avenue/US 21/Holiday Lane intersection to
travel northbound on Holiday Lane therefore a recommended distance of —800-ft from the main
intersection was used to place the roundabout. Considerations of the driveways on the west side of US 21
as well as access concerns were evaluated for several locations for the southern roundabout along US 21
north and south of the proposed southern roundabout location. The proposed location at -Y4- (the
driveway to Lucky Dog Bark and Brew) was selected to meet the spacing requirements for the U-turn
location as well as to minimize the impacts to the Environmental Justice (EJ) Smithville community since
there is a break in the houses along S. Hill Street (parallel road to the east of US 21) here. Driveways are
not recommended in close proximity to roundabouts and therefore the driveway was designed to act as a
"leg" of the proposed southern roundabout. The existing grade of the -Y4- driveway is the controlling
factor to the placement of the roundabout as the driveway is sloping down toward US 21 at an 8.5%
grade. The distance the roundabout is shown from the existing edge of US 21 at the driveway was needed
in order to get down to the roundabout elevation while also being able to maintain US 21 traffic during
construction.
The roundabout was sized based on the largest design vehicle (WB-67) expected to utilize it daily.
Shifting the roundabout to the west would require that some if not all of the parcels along US 21 in that
location to be a total take. The Town of Cornelius is currently working to revitalize this area and
removing local businesses would be detrimental to that directive. Shifting the roundabout to the east
would require additional total takes along S. Hill Street in the EJ Smithville community.

Roadway classification: Currently Holiday Lane is classified as a Local road per the NCDOT Functional
Classification GIS map shown below and after the construction of the C-5621 project, Holiday Lane will
be classified as a collector. Due to this classification, the requirement for a Hazardous Spill Basin (HSB)
at the location of the northern roundabout (Holiday Lane intersection with Sterling Bay Ln East and
West) will be analyzed on a site by site basis per Appendix O in the "NCDOT Guidelines for Drainage
Studies and Hydraulic Design 2016". More detailed site -specific information related to the determination
of why a HSB was not proposed is outlined below.
Hoene � NCDOT Functional Class
QDetails I pe13--p
o About E Content ,= Legend
Legend
NCDOT Functional Class
Functional Class
Interstate
i Other Freeway
Other Principal Arterial
— Minor Arterial
Major Collector
— Minor Collector
— Local
Project Purpose: C-5621 is designated as a project to improve mobility and safety in the area not to
increase capacity and therefore not considered a major project for NCDOT.
Safety: Roundabouts are considered a great improvement for safety as compared to traditional signalized
and unsignalized intersections. Removing the existing conflict points at the northern point of Holiday
Lane with Sterling Bay Lane East and Sterling Bay Lane West reduces the likelihood of accidents at that
location. Improved safety at this location as noted by FHWA would reduce severe accidents by 82%.
https://safeiy.fliwa. dot. goy/provencounterrneasures/roundabouts/

Constructability Impacts:
Two locations have been evaluated for an HSB to be constructed. Site 1 as shown below is on the north
side of Sterling Bay Lane East and the proposed location of the northern roundabout, while Site 2 (also
shown below) is on the south side of Sterling Bay Lane East and the proposed location of the northern
roundabout.
HSB Site 1:
HSB Site 1 (north of Sterling Bay Lane East and the proposed northern roundabout)
This HSB is shown in a linear pattern due to several site constraints; an existing sanitary sewer pump
station and apartment building located to the west and the existing apartment complex club house and
amenities located to the east. This site is wooded which would require removal of existing mature trees
and vegetation. It is located on top of a previously identified jurisdictional stream (JS). Another blue line
stream approaching from the west crossing under Sterling Bay Lane West adjoins with this JS prior to out
falling into Lake Norman. It is anticipated the blue line stream will need to be relocated in order to keep
the water separated from the proposed HSB. Stability of the banks would be a concern and additional
erosion control measures are likely to be needed. The conceptual contours for the HSB construction
shown above in magenta are a best guess as a detailed survey has not been conducted at this time. It is
unknown if the width required for the stream relocation and the proposed HSB will physically fit between
the existing physical constraints. This would also have major impacts to this property owner due to the
tree buffer being removed. As shown an extensive amount of right of way would be required in order to
construct and maintain the HSB. This property is currently in condemnation and the property owners will
likely be uncooperative moving forward. The location of the HSB at Site 1 has the potential for
previously rerouted utilities and other existing utilities to be in conflict and therefore has unknown
additional impacts at this time.

HSB Site 2:
HSB Site 2 (south of Sterling Bay Lane East and the proposed northern roundabout)
Please note in this option a preliminary revised closed storm drainage system was evaluated in order to
redirect water flow to the HSB on the south side of Sterling Bay Lane East.
An existing JS has also been identified on the south side of Sterling Bay Lane East, as well as a linear
wetland that would have potential impacts from the construction of the HSB Site 2. The conceptual
contours for the HSB shown above in white are in a rectangular pattern to best match existing site
conditions in this area.
Most of the existing tree buffer in this location would be removed exposing the residents along Burton
Lane (shown to the east of the HSB Site 2 above) to the HSB further impacting homeowners of a
previously identified EJ community. Additional right of way would be required from homeowners in
order to construct and maintain the HSB in this location. Preliminary calculations have been evaluated
revealing that in order to get the rerouted closed storm drainage system to drain to the HSB the inverts
would be at the same elevation as the existing JS. This raises concerns of exposing the existing water
table due to the low elevations required for the HSB.
The location of this HSB would also be in an area where existing and proposed utilities were routed to
avoid additional conflicts with the apartment complex on the north side of Sterling Bay Lane East.
Therefore, construction of the HSB in this location would have unknown additional utility impacts for the
project.

Public Involvement: Extensive public outreach has previously been conducted for this project due to the
sensitive nature of the surrounding neighborhoods. With Smithville neighborhood being a historically
African American community, the Title VI Environmental Justice process was implemented. Several
small group meetings have been held specifically with the Smithville community explaining in great
detail all the impacts associated with the C-5621 project as currently designed. Additional impacts to
parcels in either location (HSB Site 1 or HSB Site 2) would require additional public involvement and
engagement for the project.
Due to the reasons listed above we respectively request that the project move forward without the
construction of a hazardous spill basin for the northern roundabout.