R5763_MinimizationDesignRevisions_REV_01222021

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PROJECT MEMORANDUM

Date: January 22, 2021 (revised)
December 22, 2020

State Project: R-5763, Transylvania County.
SR 1540 (Wilson Rd) from SR 1504 (Old US 64) to US 276

From: Roy H. Tellier, PE
HNTB Roadway Design Project Engineer

Subject: Design Changes for Minimization Purposes after CP4A Meeting

Upon receipt of an updated survey file containing corrected jurisdictional features, HNTB evaluated all
jurisdictional features within the R-5763 project limits. The locations were evaluated for feasibility of
steepening slopes or other design revisions to minimize impacts. The following design changes were
made:

• Jurisdictional Stream SA (Approx. -L- Sta. 16+38, LT)
o Added Guardrail
o Steepened fill slope to 2:1 from 4:1.

• Jurisdictional Stream SD (Approx. -L- Sta. 18+43, LT)
o Added Guardrail
o Steepened fill slope to 2:1 from 4:1 behind guardrail.

• Jurisdictional Stream SG (Approx. -L- Sta. 31+30, LT)
o Added Shoulder Berm Gutter & Guardrail
o Steepened fill slope to 2:1 from 4:1 behind guardrail.
o Drainage design controls -L- RT impacts.

• Jurisdictional Stream SH (Approx. -L- Sta. 34+15, RT)
o Added Guardrail
o Steepened fill slope to 2:1 from 4:1 behind guardrail.

• Jurisdictional Stream SI (Approx. -Y3- Sta. 10+00 to 11+50, LT)
o Steepened fill slope to 2:1 in front of JS.

• Jurisdictional Streams SP & SQ (Approx. -L- Sta. 75+61 to 79+06, LT/RT)
o Added Shoulder Berm Gutter & Guardrail on LT side of -L-.
o Steepened fill slope to 2:1 from 4:1 behind guardrail.
o On -L- RT side, steepening slopes would not eliminate impacts. Streams also pass under
re-aligned road in some locations.

• Jurisdictional Stream SZ (Approx. -L- Sta. 170+63, LT)
o Removed ditch section and replaced with 4:1 fill slope to bring slope stake in.

• Wetland WF (Approx. -L- Sta. 32+76 to 36+22, LT)
o Added Shoulder Berm Gutter & Guardrail
o Steepened fill slope to 2:1 from 4:1 behind guardrail.

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The table below shows the amount of impacts using slope stake limits plus 25 feet as presented at
CP 4A and for the streams and wetland with design changes.

Stream ID Perennial/
Intermittent
Impacts from
CP 4A (SS+25’)
(ft)
Impacts from
Design
Revision
(SS+25’) (ft)
Difference (ft)
SA Perennial 432 417 15
SD Perennial 117 96 21
SG Perennial 161 151 10
SH Perennial 88 70 18
SI Perennial 164 125 39
SP Perennial 314 314 0
SQ Intermittent 22 22 0
SZ Perennial 165 165 0
Total Reduction 103 ft

Wetland ID WAM Type
Impacts from
CP 4A (SS+25’)
(ac)
Impacts from
Design
Revision
(SS+25’) (ac)
Difference (ac)
WF Floodplain Pool 0.13 0.06 0.07

The following locations were evaluated, but no design changes were made for the reasons listed:

• Jurisdictional Stream SA (Approx. -Y2- Sta. 10+00 to 11+91, LT)
o Impacts to JS are mostly outside of slope stakes. Areas that are impacted are within a
minimum ditch section or underneath the re-aligned road, so design changes have been
implemented.

• Jurisdictional Stream SB (Approx. -L- Sta. 14+18, RT)
o Impacts to JS are within a minimum ditch section, so no design changes have been
implemented.

• Jurisdictional Stream SE (Approx. -L- Sta. 22+27, LT)
o Slopes were already 2:1 behind guardrail in this section.

• Jurisdictional Stream SF (Approx. -L- Sta. 22+45, RT)
o Previous design had no impacts.

• Jurisdictional Stream SJ (Approx. -Y3- Sta. 28+90, LT)
o Previous design had no impacts.

• Jurisdictional Stream SK (Approx. -L- Sta. 46+50, RT)
o Previous design had no impacts.

• Jurisdictional Streams SL, SM, SN (Approx. -L- Sta. 55+20, LT/RT)
o No changes to design due extensive coordination with SHPO & Division. Drainage
design controls in this area.

• Jurisdictional Stream SO (Approx. -L- Sta. 63+25, LT)
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o No design changes made. Steepening slopes would not eliminate impacts. Stream
currently is routed through a culvert system in this area.

• Jurisdictional Stream SR (Approx. -DRW2- Sta. 11+45, LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.

• Jurisdictional Streams SS & ST (Approx. -L- Sta. 90+00 LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.

• Jurisdictional Stream SU (Approx. -L- Sta. 94+40 LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.

• Jurisdictional Stream SV (Approx. -L- Sta. 132+75 RT)
o Previous design had no impacts.

• Jurisdictional Stream SW (Approx. -L- Sta. 150+00 LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.
• Jurisdictional Stream SX (Approx. -L- Sta. 151+88 LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.

• Jurisdictional Stream SY (Approx. -L- Sta. 158+50 LT/RT)
o No design changes made. Drainage designs to re-align channel control in this location.
Stream runs underneath re-aligned Wilson Rd for some distance. Guardrail and 2:1
slopes were already used on LT side of -L-.

• Jurisdictional Stream TB/SBB (Approx. -L- Sta. 177+75 LT to 188+65)
o No design changes made. Steepening slopes would not eliminate impacts.

• Jurisdictional Stream TA/SAA (Approx. -L- Sta. 178+30 RT to 189+25 LT)
o No design changes made. Steepening slopes would not eliminate impacts.

• Cateechee Branch CB (Approx. -L- Sta. 63+12 to 68+50, LT/RT)
o No design changes made. Steepening slopes would not eliminate impacts. Stream will
be picked up in pipes and routed to existing outfall.

• Wetland WA (Approx. -L- Sta. 15+10 to 15+76, RT)
o Impacts to this wetland are created by a special ditch section, so design changes have
been implemented.

• Wetland WB (Approx. -L- Sta. 16+22 to 16+40, RT)
o Impacts to this wetland are created by minimum ditch section, so design changes have
been implemented.

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• Wetland WC (Approx. -L- Sta. 18+18 to 18+35, RT)
o Impacts to this wetland are created by special ditch section, so design changes have
been implemented.

• Wetlands WD & WE (Approx. -L- Sta. 22+13 to 22+70, RT)
o Impacts to these wetlands are created by drainage designs. Due to the proximity to
driveways, steepening the slopes and adding guardrail is not feasible due to sight
distance concerns.

• Wetlands WH & WS (Approx. -L- Sta. 75+61 to 79+06, LT/RT)
o On -L- RT side, steepening slopes would not eliminate impacts. Streams also pass under
re-aligned road in some locations.

• Wetland WJ (Approx. -L- Sta. 151+00, RT)
o Previous design had no impacts.

• Wetland WK (Approx. -L- Sta. 158+50, RT)
o Previous design had no impacts.

• Wetland WL (Approx. -L- Sta. 186+75, RT)
o No design changes made. Proposed bridge alignment crosses over wetland.

• Wetland WM (Approx. -L- Sta. 182+50, RT)
o Previous design had no impacts.

• Wetland WN (Approx. -L- Sta. 181+75, RT)
o No design changes made. Impacts are controlled by bridge construction.

• Wetland WO (Approx. -L- Sta. 191+50, LT)
o Previous design had no impacts.

• Wetland WP (Approx. -L- Sta. 191+05, RT)
o No design changes made. Impacts are controlled by bridge construction.

• Wetland WQ (Approx. -L- Sta. 14+18, RT)
o Previous design had no impacts.

• Wetland WR (Approx. -Y6- Sta. 12+25, LT)
o Previous design had no impacts.

If you have any questions or need any additional information, please contact me at [phone], or
by e-mail at [e-mail].

Sincerely,
HNTB North Carolina, P.C

Roy H. Tellier, PE
Roadway Design Project Engineer