CA FTNP SEKI 13(2) Mineral King Road Final Hydraulics Report with Addendum.pdf

Appendix A – Drainage Basin Delineations CA FTNP SEKI 13(2) Mineral King Road - Hydraulics Report

Note: STA 224+49 and STA 225+64 have been merged for one proposed structure. Basins have been added together for the proposed model.

Note: STA 588+20.00 has been updated to STA 590+19.97

Appendix B – FEMA Flood Insurance Study Map CA FTNP SEKI 13(2) Mineral King Road - Hydraulics Report

Project Start

Project Corridor

Appendix B – FEMA Flood Insurance Study Map CA FTNP SEKI 13(2) Mineral King Road - Hydraulics Report

Project End

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Station

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

100+68.45 12 30 30 CMP CBI FES, apron, move outlet 5' upstation Radiator Basin X

102+71.14 12 24 24 CMP CBI FES, apron

104+29.48 14 24 24 CMP CBI Steepen pipe, FES, apron

106+00.01 12 24 24 CMP CBI

FES, apron. Relocate outlet ~15' up station so perpendicular.

107+39.33 18 24 24 CMP Modified CBI (L shape) FES, apron

109+16.18 12 24 24 CMP

Move inlet 8 ft. up station, DS shorten length, 20' rundown, FES, apron.

Move outlet 30' upstation to approximately 30 deg skew across road due to scour hole.

110+90.73 15 24 24 CMP pull inlet in 5', DS FES, apron, fill in scour hole

113+82.39 17 24 24 CMP CBI FES, apron

116+73.16 18 30 30 CMP CBI

15' rundown, FES, apron, relocate outlet

30' up station X

119+03.89 18 30 30 CMP DS Steepen pipe, FES, apron X

123+85.20 18 30 30 CMP DS 20' rundown, FES and apron X

125+14.64 12 24 24 CMP CBI FES, apron, reset rock wall (4' high wall)

126+38.32 18 24 24 CMP DS FES, apron

128+84.01 12 24 24 CMP CBI 20' rundown, FES, apron

130+02.68 18 24 24 CMP pull inlet in 1', DS Remove and reset outlet wall, 15' rundown, FES, apron

132+78.01 18 24 24 CMP CBI FES, apron

134+31.19 18 24 24 CMP DS

Remove and reset dry stack outlet wall, move outlet 20' upstation, 20' rundown, FES, apron

Outlet wall is approx. 20' long, 14' deep

136+37.94 18 24 24 CMP DS 25' rundown, FES, apron

137+17.65 18 30 30 CMP CBI

move outlet 30' so near perpendicular, FES, apron

18' high soil nail wall, 20' long at existing erosion location

X

138+66.72 8 24 24 CMP CBI FES, apron Inlet does not need to be so deep (~3') Existing structure size is missing from survey.

139+79.90 12 24 24 CMP DS

Move outlet 20' upstation, 20' rundown, FES, TRM

142+17.32 18 24 24 CMP CBI

Move outlet 5' up station, 20' rundown, FES, TRM

144+16.01 12 24 24 CMP CBI 25' rundown, FES and apron

146+63.88 18 30 30 CMP CBI

relocate outlet 25' down station, 25' rundown, FES and apron X

149+43.77 12 36 36 CMP CBI

relocate entire pipe down station ~70' to ~148+70. 40' rundown, FES and apron

Pave 22' width and berm SRE max 10' high

STA 149+28

149+59.

XX

152+87.44 18 24 24 CMP DS 25' rundown, FES, improve apron

154+00 Unknown 24 24 CMP DS 20' rundown, FES, apron This culvert was not captured by survey.

156+80 Unknown 24 24 CMP DS 30' rundown, FES, TRM, relocate outlet 30' upstation This culvert was not captured by survey.

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

159+06.17 12 24 24 CMP DS (L shaped headwall) 25' rundown, FES, improve existing apron

~STA 159, 100'

deep patch to address half moon

161+37.78 12 24 24 CMP CBI 25' rundown, FES, TRM

162+50.37 18 24 24 CMP DS 45' rundown, FES, outlet on existing rock

162+78.61 12 24 24 CMP DS 45' rundown, FES, outlet on existing rock

163+01.28 12 24 24 CMP DS 45' rundown, FES, outlet on existing rock

164+68.41 8 24 24 CMP CBI 50' rundown, FES, TRM

165+54.39 12 24 24 CMP DS FES, TRM

166+43.34 12 30 30 CMP CBI steepen pipe, improve existing apron, FES add spillway assembly ~STA

167+00 X

171+10.77 12 24 24 CMP CBI 45' rundown, FES, apron back skew (sag) upstation at

45 degrees so outlet is upstation 30'

172+55.77 12 24 24 CMP CBI 30' rundown, TRM

175+00.39 12 30 30 CMP CBI

50' rundown and apron relocate outlet upstation to just down station of the apex of bend (~40') regrade down station inlet ditch to drain

X

179+24.48 12 24 24 CMP CBI

Remove and reset outlet headwall (10'), improve existing apron, FES regrade down station inlet ditch from 178+00 to structure inlet to drain

183+20.19 12 24 24 CMP DS Remove and replace outlet wall, FES, apron Move spillway assembly upstation 25'

190+94.09 12 24 24 CMP DS Apron, FES

194+52.63 12 24 24 CMP DS 20' rundown, outlet on existing rock

196+41.38 18 24 24 CMP DS FES, apron

200+61.51 18 30 30 CMP DS rundown (length not noted), TRM X

207+86.79 12 24 24 CMP DS FES, apron

Skew 55 60 degrees. Use type ~II riprap to address erosion at ~205+40, curb and spillway assembly

212+08.29 15 30 30 CMP DS FES, apron X

214+71.52 12 24 24 CMP CBI

Shorten length (so not projecting), FES, TRM

218+89.44 12 24 24 CMP DS (remove/reset) 25' rundown, FES, outlet on existing rock

223+31.74 12 24 24 CMP CBI Steepen a hair, FES, apron

224+49.46 15 Remove pipe completely

225+64.65 30 49 33 CMPA FES

Remove/reset outlet wall, FES, improve existing apron Steepen pipe X X

228+08.63 12 24 24 CMP DS (remove/reset) steepen, skew less (30 deg.), apron, FES 9ft drop at the outlet

231+55.11 12 24 24 CMP CBI, move 2' upstation reset outlet wall (10'), 50' rundown, FES, apron

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

237+73.27 12 24 24 CMP DS FES, improve apron

240+70.65 18 35 24 CMPA FES FES, improve apron X

245+20.52 12 24 24 CMP

DS, move inlet 5' upstation 40' rundown, apron

248+17.86 15 30 30 CMP CBI FES, apron relocate upstation 15', skew less X

250+04.34 10 24 24 CMP CBI 40' rundown, apron

251+82.05 12 24 24 CMP FES 45' rundown, apron

254+55.75 12 24 24 CMP CBI

FES, apron, relocate outlet closer to 90 deg skew across road fill in existing scour hole at outlet with riprap

257+47.44 10 24 24 CMP DS FES, improve existing apron

257+86.10 12 24 24 RCP FES

FES, apron, relocate outlet to 90 deg skew across road granite may limit inlet, shorten pipe outlet so it is not projecting from the slope.

259+97.22 12 24 24 CMP DS FES, apron, shorten so not projecting

263+39.91 30 42 42 CMP

FES. Remove and reset stone headwall.

Remove/reset outlet rock wall, improve existing apron Radiator Basin X

263+98.04 12 24 24 CMP DS FES, apron, remove/reset outlet wall steep pipe Move entire pipe upstation 5' to 264+03.04

265+74.96 15 24 24 CMP DS FES, apron, keep existing location there is a culvert here (survey only shows spillway assembly just down station)

267+66.15 12 30 30 CMP CBI

40' rundown, apron, FES, move outlet 10' up station X

271+58.87 12 24 24 CMP DS FES, apron, move outlet 10' up station

275+66.62 18 24 24 CMP DS

15' rundown, FES, apron, relocate outlet

10' upstation

279+76.85 15 24 24 CMP DS steepen, apron, FES

281+51.03 15 30 30 CMP DS 15' rundown, FES, apron X

285+84.64 15 24 24 RCP DS FES, TRM

288+23.55 12 24 24 CMP CBI

FES, apron, relocate outlet to nearly 90 deg skew across road approx. 10' up station

292+38.73 18 30 30 CMP CBI

FES, 20' rundown, apron, move outlet 10' up station so perpendicular regrade ditch above X

297+35.13 12 24 24 RCP DS FES, apron, move outlet 10' upstation

300+94.81 12 30 30 CMP CBI

FES, 20' rundown, apron, relocate outlet

20' upstation so perpendicular X

305+70.03 12 24 24 CMP CBI FES, apron, steepen leave in existing location, steepen a hair. Regrade u/s ditch to drain/fit pipe.

309+74.65 18 36 36 CMP FES FES, apron X

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

312+62.78 12 24 24 CMP CBI FES, 20' rundown, TRM

316+16.93 18 24 24 CMP CBI FES, 20' rundown, TRM

322+75.00 Unknown 36 36 RCP FES FES, apron Regrade 30' upstream.

This culvert was not captured by survey.

X X

325+35.47 18 30 30 CMP CBI

FES, 30' rundown, apron. Move outlet 30' upstation, so perpendicular.

SRE max 6' high

STA 325+20

325+50 X

328+92.36 12 30 30 CMP CBI

30' rundown, apron, move outlet 30' up station

SRE max 10' high, located to stabilize existing culvert outlet, STA 328+75 329+00

X

331+73.01 12 24 24 CMP CBI FES, 25' rundown, apron

343+39.84 12 30 30 CMP DS FES, apron X

345+70.05 12 24 24 CMP DS

FES, 20' rundown, TRM, move outlet 20' upstation

348+42.18 12 24 24 CMP CBI

30' rundown, FES, apron, relocate to

347+42

351+46.59 18 24 24 CMP CBI FES, apron, steepen

352+84.83 18 30 30 CMP CBI FES, apron X

354+64.71 18 36 36 CMP FES

FES, 30' rundown, apron, skew perpendicular X

356+04.67 12 24 24 CMP DS FES, apron

359+67.07 18 30 30 CMP DS FES, 70' rundown, apron Rundown will be visible Boulder wall from Sta. 359+50 to

361+00 X

363+29.36 24 30 30 CMP DS (remove/reset) FES, 40' rundown, apron

366+58.94 18 36 36 CMP CBI

FES, 30' rundown, apron. Relocate outlet upstation 20'.

Soil nail wall 365+85 to 366+15, soldier pile wall

366+15 to 366+60

XX

369+12.18 24 30 30 CMP DS

Move outlet up station 5', 15' rundown, FES, apron

Radiator basin. Add 12" pipe bedding above and below the culvert to mitigate risk of point loading/crushing.

See Special 252 B UT FLAP 70131(1) Strawberry Sheep

Creek.

SRE max 10' high, STA 369+00

369+25.

369+54.79 6 Remove existing structure (could also clean inlet and leave in place)

370+17.04 18 30 30 CMP DS (remove/reset) FES, 20' rundown, outlet on existing rock

373+58.34 18 24 24 CMP DS FES, 20' rundown, improve existing apron

378+74.67 18 30 30 CMP DS FES, apron X

383+02.94 18 24 24 CMP

DS (reset disturbed portion of the wall)

FES, 35' rundown, apron

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

383+64.27 24 24 24 CMP DS (remove/reset) FES, apron

386+81.41 12 24 24 CMP DS FES, apron, steepen

389+49.92 18 30 30 CMP CBI 40' rundown, FES, move outlet to 389+70 No SRE. Deep patch at this location.

X

392+70.83 12 36 36 CMP

CBI, move to station

392+90 so outside of wall limits

FES, 30' rundown, TRM

Soldier pile wall extends from Sta.

392+40 to 392+85.

Relocate.

XX

395+00.00 18 36 36 CMP CBI FES, 40' rundown, apron Move pipe from 395+00 to

395+80

This culvert size was not captured by survey. Bad erosion site at 395+00.

Soil nail wall extends from

394+50 to 395+10.

Relocate culvert outside wall limits.

X XX

400+06.28 Unknown Remove pipe completely This culvert size was not captured by survey.

400+34.06 18 24 24 CMP DS

FES, 20' rundown, outlet on existing rock.

Do not disturb outlet wall.

inlet channel intersects road at 390+00.

401+28.61 18 24 24 CMP DS

FES, 15' rundown, apron. Move outlet 10ft up station.

404+20 18 30 30 CMP DS

30' rundown (anchor to boulders using concrete expansion anchors), improve apron, outlet away from toe of wall.

This culvert was not captured by survey.

Existing is a plugged 18" pipe.

SRE max 10� high, abut to existing dry stack rock wall, construct berm over top of SRE and existing dry stack to control surface drainage, STA 404+00

404+20

X

405+83.10 18 30 30 CMP CBI FES, 20' rundown, TRM X

407+68.27 15 24 24 CMP DS (remove/reset) FES, apron

410+57.93 15 24 24 CMP DS FES, apron

412+82.22 15 24 24 CMP DS FES, apron

414+06.96 17 30 30 CMP DS FES, apron Skew less since trees are in the way.

X

417+92.31 18 24 24 CMP

DS, move inlet 3' upstation FES, 30' rundown, apron, move outlet 20' upstation

423+69.61 18 24 24 CMP

Move inlet 2' closer to

EOP, DS

FES, 40' rundown, apron

Reduce skew to avoid trees at outlet, 10' down station

426+41.77 18 24 24 CMP

Move inlet 2' closer to

EOP, DS

30' rundown, FES, apron

428+75.41 12 24 24 CMP Modified CBI (L shape) 15' rundown, FES, apron

432+90.91 12 24 24 CMP CBI, abut onto rock 15' rundown, FES, TRM

436+02.90 12 24 24 CMP

Move inlet 2' closer to

EOP, DS

10' rundown, FES, apron

441+63.72 12 30 30 CMP DS 50' rundown, FES, apron road slipping out / half moon X

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

444+07.58 48 81 59 CMPA

Conc. HW and DSWW are recommended due to this being a sequoia root mitigation location.

Conc. HW and DS WW are recommended due to this being a sequoia root mitigation location. Improve existing apron.

Radiator Basin Redwood Creek

Salvage existing DS wall.

Within sequoia mitigation zone. Roots are visible over culvert.

Consider hand digging with potential for modified design if conflicts are identified.

X X

446+65.50 12 24 24 CMP DS (remove/reset) 5' rundown, FES, apron

449+49.45 12 24 24 CMP DS FES, tie apron into existing rocks

451+41.14 12 24 24 CMP DS 50' rundown, FES, apron Reset 15' high dry stack wall at outlet

453+60.90 15 30 30 CMP CBI FES, TRM

skew outlet 15' down station.

X

456+70.93 12 24 24 CMP CBI FES, apron Drop inlet 1' minimum.

Steepen pipe to outlet at grade.

458+82.59 18 36 36 CMP DS

FES, apron, reset outlet wall. Match existing outlet invert elevation.

Reset 7' high dry stack wall at outlet.

X X

460+01.26 18 Remove culvert

462+00.56 12 24 24 CMP CBI FES, install limited apron around trees Drop inlet 1' minimum

466+00.90 24 36 36 CMP DS 10' rundown, FES, improve outlet apron Reset dry stack at inlet: 4', and outlet: 12' high.

X

466+89.60 15 30 30 CMP DS 30' rundown, FES, apron X

469+45.16 12 24 24 CMP DS FES, apron

471+53.43 18 24 24 CMP

Move inlet 2' toward EOP, DS

30' rundown, FES, apron

474+18.81 15 24 24 CMP CBI FES, apron

477+57.00 18 24 24 CMP CBI FES, apron

480+86.16 18 24 24 CMP DS 15' rundown, FES, apron

483+29.79 18 24 24 CMP CBI FES, apron

485+10.07 15 30 30 CMP

Shift inlet 5' toward EOP, DS

FES, apron

5' boulder sitting on outlet

488+93.58 12 24 24 CMP CBI FES, apron Shift outlet 5' upstation

491+36.04 12 35 24 CMPA DS (remove/reset) FES, apron X X

493+68.02 15 24 24 CMP DS FES, apron

497+12.18 15 24 24 CMP DS (remove/reset) FES, apron

498+99.94 18 24 24 CMP

Shift inlet 2' away from

EOP, DS

FES, apron

502+04.65 18 24 24 CMP CBI FES, apron

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

504+46.88 15 24 24 CMP CBI FES, apron

506+81.88 18 24 24 CMP CBI FES, apron, shift outlet 5' upstation

514+58.66 12 24 24 CMP DS FES, apron

517+83.22 15 24 24 CMP CBI 20' rundown, FES, apron

520+70.73 36 36 36 CMP FES FES, apron Reset 10' high dry stack wall at outlet

X

523+04.42 24 24 24 CMP CBI FES, apron

528+37.29 15 36 36 CMP

DS (remove/reset), raise inlet 1 2' Reset outlet wall, FES, apron Match existing pipe slope.

Reset dry stack walls, 10' at inlet, 14' at outlet.

X

537+50.93 18 24 24 CMP CBI FES, apron

542+15.45 18 24 24 CMP DS 20' rundown, FES, apron Reset dry stack walls, 5' at inlet, 12' at outlet

546+46.42 12 24 24 CMP CBI FES, apron

563+51.94 18 36 36 CMP

Shift inlet 10' upstation, FES. Raise inlet ~3'.

FES, Improve existing apron

Within sequoia mitigation zone. 4' DBH tree located near culvert inlet. Avoid roots with reinstallation.

X X

572+05.50 18 24 24 CMP CBI 30' rundown, FES, apron

590+19.97 30 57 38 CMPA

FES and DS headwall.

Lower inlet invert to improve cover and mitigate overtopping

FES and DS headwall, apron, extend end of outlet 10'

Large logs acting as existing headwall.

Within sequoia mitigation zone, avoid roots with reinstallation.

Reduce size if large roots are encountered.

X

591+05 New Proposed

Culvert 24 24 CMP CBI FES, apron

Re establish ditch 30' up and 80' down station

592+17.30 8 24 24 CMP CBI FES, apron regrade upstation ditch

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

595+96.55 30 64 43 CMPA Conc. HW/WWs Conc. HW/WWs

Adjust inlet/outlet to edge of log HW to maintain roadway width.

Superelevation puts water over outlet. Reinstall spillway assembly such that it does not obstruct the culvert outlet e.g. add weir cut to outlet HW for spillway assembly.

Size is missing from survey.

X X

597+53.79 8 24 24 CMP DS FES, apron

Clean debris from obstructing pipe that is ~50

ft. downstream running beneath service road

602+19.67 18 35 24 CMPA FES FES, apron Water supply pipe at inlet. Inlet overlain by asphalt.

X

610+62.85 18 24 24 CMP DS FES, apron Adjacent to Atwell Mill

Campground.

Within Sequoia

Mitigation Zone with large roots, avoid roots during reinstallation.

613+42.00 8 18 18 CMP DS

FES, no apron, shift outlet away from driveway, graded ditch between two.

Replace downstream campground pipe with 18" no end sections (per PM). No apron.

18�x30� underneath campground road. Skew pipe under Mineral King and provide ditch between both pipes, approximately 20�.

No outlet treatments and no inlet treatment for pipe under campground road.

Adjacent to Atwell Mill Campground. Outlets into very small pipe

~8in at the campground entrance. Hydraulic model indicates this should be upsized to a 24 in. pipe. Due to geometric limitations, PM was consulted and determined that an 18

in. size would be installed here.

Within sequoia mitigation zone, avoid roots with reinstallation.

633+30.71 18 30 30 CMP CBI

30' rundown, FES, apron. Reset dry stack wall over outlet Falling rock wall at existing outlet.

Reset SRE max 10' high, STA 633+20 633+40. Add berm across top of wall.

X

636+93.06 24 42 42 RCP

Remove/replace mortared stone headwall.

FES, apron, fill in scour hole

Invert elevation is lower than existing. Regrade upstation ditch to drain

(right now bypasses culvert and stagnates in ditch down station).

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

640+07.45 12 24 24 CMP DS

FES, apron. Skew culvert outlet away from spillway assembly

643+87.83 12 24 24 CMP

Shift inlet 2' toward EOP and upstation 5', DS

FES, apron Existing outlet is buried.

Within sequoia mitigation zone (sequoia near inlet).

Avoid roots with reinstallation.

646+87.36 12 30 30 CMP DS FES, apron upsized to a 30" pipe due to the abandoned pipe at 648+90

648+90.64 18 Abandon and flow fill culvert.

Within sequoia mitigation zone. Massive sequoia on inlet side, large roots.

673+14.02 18 42 29 CMPA FES FES, apron Lengthen pipe 1' 4' Reset dry stack wall

679+03.24 12 24 24 CMP DS FES, apron half buried X

681+32.77 24 24 24 CMP DS FES, apron, reset outlet wall need to reestablish ditch to fit (50'+ upstream)

681+90 New Proposed

Culvert 24 24 CMP DS FES, apron

Keep adjacent culvert. Add new culvert at 681+90 stream/road intersection.

Include small grade raise here if possible.

690+09.42 24 64 43 CMPA Conc. HW/WWs Conc. HW/WWs. Apron, reset rock wall to tie into WWs

Regrade inlet down station ditch to drain (~40').

Regrade inlet channel, remove debris. Keep spillway assembly, longer detail.

Dry stack rock wall extends from Sta.

689+90 to 690+30, max. height = 12'.

X

699+05.10 36 42 42 CMP DS

remove/reset outlet headwall, steepen 0.5

0.75', apron Replace spillway assembly X

710+88.82 18 24 24 CMP DS FES, apron

Just downstream there is a service road with a cross culvert that has a buried inlet recommend that this be cleaned.

717+29.01 30 36 36 CMP FES

FES, improve apron, lower outlet invert

~1.5' Remove old pipes in streambed

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

726+75.81 24 30 30 CMP DS (remove/reset) 20' rundown, FES, outlet on existing rock

Replace spillway assembly, long detail so outlets on existing rock. Will need to lower inlet invert elevation to meet cover.

X

737+80.23 18 24 24 CMP DS FES, apron Regrade ditch to drain Inlet is buried

740+13.23 12 42 29 CMPA DS FES, apron regrade upstream channel

30'.

X

749+80.02 60 60 60 CMP Conc. HW/WW Conc. HW/WW. Apron. Drop outlet ~1' to match local channel slope

Superelevate road to outlet, two spillway assemblies are present, the upstation spillway assembly will need to be extra long to outlet on apron.

Existing structure size is hydraulically adequate.

Replace structure with same size CMP equipped with headwalls and wingwalls.

salvage existing dry stack rock walls, 10' 13' high.

X

753+07.74 18 24 24 CMP DS FES, improve apron around trees

768+58.02 24 24 24 CMP DS (remove/reset) FES, apron

771+97.33 24 24 24 CMP

FES, Pull inlet 5' towards road FES, improve apron

782+77.08 18 35 24 CMPA DS (remove/reset) remove/reset outlet wall (granite). Use type III riprap for apron.

X

785+06.43 12 24 24 CMP CBI

20' rundown, apron, rebuild top of wall (the part of wall we have to disturb to remove pipe) Relocate to station 784+90

Leave existing rock wall in place (minimize disturbance)

795+53.67 24 24 24 RCP DS (remove/reset) FES, apron. Remove/reset 5' high dry stack wall at outlet near to no cover, expect bedrock very close to invert

804+35.88 24 36 36 RCP DS, lower inlet ~1.5' FES, outlet onto existing rock, improve apron, lower outlet ~2.5' pipe can be shortened X

809+44.51 18 35 24 CMPA FES FES, improve apron X

812+77.56 6 24 24 CMP DS, lower inlet 12" FES, apron, lower outlet 24"

813+85.27 12 24 24 CMP CBI FES, apron, lower outlet 24"

816+03.32 18 24 24 CMP DS FES, improve apron Remove/reset dry stack wall

825+59.41 18 35 24 CMPA FES FES, apron, lower outlet 1' Existing inlet is buried. X

836+69.17 18 24 24 CMP

Remove and replace mortared stone box inlet in kind

DS (trees in way), apron

841+72.52 15 24 24 CMP DS FES, apron, raise outlet 6" regrade outlet to drain, improve inlet ditch

(upstation). water supply pipe at outlet

846+23.68 24 24 24 CMP DS FES, apron

849+25.00 Unknown 24 24 CMP DS FES, apron regrade inlet upstation ditch to drain This culvert was not captured by survey.

852+80.19 24 24 24 CMP DS 20' rundown, FES, apron Outlets into river

856+59.42 18 24 24 CMP DS FES, Apron

858+14.59 18 42 29 CMPA

DS (remove/replace mortared stone headwall) FES, apron regrade upstream/upstation ditch to drain plugged with sediment, there is an existing debris rack

Appendix G Hydraulics Culvert Inventory and Recommendations CA FTNP SEKI 13(2) Mineral King Road Hydraulics Report

Existing Structure Size

(dia. or width x height, in.)

Proposed Structure Span

(in.)

Proposed Structure Depth (in.)

Proposed Structure Type

Proposed Inlet Notes/End Treatment

Proposed Outlet Notes/End Treatment Design Note Miscellaneous Culvert

Note Geotechnical / Rock Wall Note

Sequoia Root Mitigation Location

Debris/ Sediment Passage or Accumulations

Fisher/ Wildlife Crossing

Major Erosion Site (XX designates extreme erosion)

858+67.35 18 24 24 CMP DS FES, apron There is an existing debris rack

860+65.42 12 24 24 CMP DS FES, apron

862+54.71 30 30 30 CMP DS FES, apron

864+47.41 30 30 30 CMP DS FES, apron

866+98.56 18 24 24 CMP DS FES, apron Increase pipe grade to 6%

8% Build up slope to

1:1

872+11.42 48" and adjacent

36" 72 72 CMP Conc. HW/WW

Conc. HW/WW, outlet on existing rock.

Drop outlet up to 4.5' grade ditch 80' upstation to match inlet invert and structure slope

Existing structure size prior to sedimentation is hydraulically adequate. Replace with one larger structure, with flared wingwalls and a steepened invert to better match into local channel slope in an effort to improve sediment continuity through the reach.

Structure is hydraulically oversized due to recurring sediment deposition issues.

X

874+00 Unknown 24 24 CMP DS FES, apron This culvert was not captured by survey.

888+72.99 Approx. 117"x79"

CMPA

117 79 CMPA Conc. HW/WW

Conc. HW/WW. Apron. Drop outlet invert ~6" (scour hole).

Existing structure is hydraulically adequate.

Replace with approximately the same structure size, improve inlet and outlet end treatments and outlet apron.

X X

888+95.20 36 36 36 CMP

Remove/replace mortared stone headwall. Remove debris from immediately upstream and lower inlet invert.

FES, apron Remove (do not replace) debris rack for fisher passage.

Overflow pipe for flood chute.

890+03.63 24 36 36 RCP FES FES, apron shorten length 8'

892+21.28 24 24 24 CMP FES FES, apron

Acronyms:

EOP = edge of pavement, SRE = Special Rock Embankment, TRM = Turf Reinforcement Matt DS = Dry Stack Headwall, HW/WW = Headwall / Wingwalls, CBI = Concrete Box Inlet

Addendum

Subject: CA FTNP SEKI 13(2) Mineral King Road– Date: July 2024 Final Hydraulics Report Drop Inlet Analysis

To: Neil Ogden, PE, Project Manager, CFLHD

From: Amanda Peters, Hydraulic Engineer, CFLHD Signature: ____________________

Through: Luis Calderon, PE, CFM, Lead Hydraulic Engineer, CFLHD Signature: ___________________

Summary

The purpose of this addendum is to describe the analysis completed for the proposed drop inlets along Mineral King Rd. that will be installed in lieu of concrete box inlets at locations where paved ditch ties into the culvert inlet. Locations where a drop inlet will be placed were analyzed to determine efficiency of the inlet and the width of flow encroachment onto the pavement. Table 1 below provides locations where a deviation from the standard drop inlet and grate size is recommended for use. The standard grate used in this analysis (and recommended for all other drop inlet locations) is a 45 degree tilt-bar with 2-1/4 in grate spacing, which closely aligns with FHWA standard detail 604-3 (FHWA, 2005). The catch basin recommended for use is illustrated in standard detail 604-1 (FHWA, 2005). For the grates shown in Table 1 below, the grate spacing is recommended to remain the same as what is shown in standard detail 604-3.

Table 1: Specific Drop Inlet Recommendations

Station Culvert Size (in) Q10 (Cfs) Grate Width (ft) Grate Length (Ft)

106+00.01 24 20 2.5 6.67 166+43.34 30 19 2.5 8.33 175+00.39 30 4.3 2.5 8.33 179+24.48 24 5.3 2.5 6.67

Discussion

Design Criteria

As described in section 2 of this report, Mineral King Rd. is considered a low standard road for hydraulic design purposes. The PDDM was used to determine design criteria. Table 2 below provides hydraulic design criteria used. An average 10-ft lane was assumed along the corridor, meaning that the spread should be limited to 5-ft.

Table 2: Hydraulic Design Criteria

Low-Standard Roadway

Design Frequency

Design Criteria

Pavement Drainage 10-yr

Spread: Half of one travel lane Depth: Not to exceed curb height

Clogging Factor: Grate inlets in sag, 50% Minimum recommended capture efficiency for on-grade inlets: 70%

Hydrology

In order to analyze the proposed drop inlet grate locations along the corridor, the Q10 was determined.

The Rational Method was used at all locations with a runoff coefficient of 0.3. This was determined using drainage area in conjunction with NOAA Atlas 14 (NOAA, 2014) to determine precipitation intensities. A time of concentration value of 10 minutes was used for all crossings, which is the minimum recommended time for rural and undeveloped areas (Caltrans, 2020).

Hydraulic Analysis

The hydraulic toolbox (FHWA, 2024) was used to analyze the proposed drop inlets along Mineral King Rd. An average ditch width of 3-ft was used for all inlets, although the ditch width varies along the corridor. A 6 in curb will be used at all locations. The cross slope of the ditch used was 1V:8H and a 2% pavement cross slope was assumed for all locations. The roadway grade just upstream of each inlet location was used in the analysis.

The results of this analysis showed that the efficiency of the majority of the drop inlets is high, ranging from 73% to 98% for on grade inlets. The minimum recommended capture efficiency for on-grade inlets is 70%, per PDDM section 7.3.3.4.2. There is only one location that does not meet a minimum 70% efficiency. At sta. 106+00.01, the hydraulic analysis shows that the efficiency of the proposed grate size is 56% with a spread of 9.8 ft. Although this does not meet design criteria, there is another culvert less than 200 ft downstream (and additional culverts past this one) with additional capacity that will be able to accept flow that bypasses the inlet at sta. 106+00.01. At sta. 166+43.34, with a double box/grate (which doubles the length of the inlet) the efficiency of the inlet is 78%. The width of spread is 10.5-ft, greater than ½ lane. For both sta. 106+00.01 and sta. 166+43.34, a 3-ft ditch was assumed in the analysis. A wider ditch would decrease the width of spread at these locations.

Two additional locations are recommended to have double boxes/grates. At sta. 175+00.39 and 179+24.48, the inlets are in a roadway sag. Following guidance set forth in PDDM section 7.3.3.3.3, a clogging factor of 50% was used. Using a double box/grate inlet with this clogging factor, the width of spread at the sag is 10 ft at sta. 175+00.39 and 11.7 ft at sta. 179+24.48. When the clogging factor is changed to 0, the width of spread is only 3 ft and 4.5 ft, respectively. There is minimal large debris along the corridor, and most debris is sediment that should be able to pass through the grates. Therefore, the width of spread value with a 50% clogging factor is likely a conservative estimate and actual clogging effects will be lower. Even when using a clogging factor of 50%, the water depth at the center of the grate is shallow, between 4 and 5 in. In an effort to minimize the number of inlets along the corridor, flanking inlets were not considered at sag locations here as this would add additional drainage features and cost to the project. Regular maintenance is recommended on all these inlets to ensure they are free of debris and functioning properly.

References

Caltrans. (2020). Highway Hydrology Manual, Chapter 810: Hydrology.

FHWA. (2005). Standard Detail 604-3: Metal Frame and Grate, Type B.

FHWA. (2005). U.S. Customary Standard 604-1: Catch Basin, Type 1.

FHWA. (2024). HDS-2: Highway Hydrology, Third Edition.

FHWA. (2024, February 21). Hydraulic Toolbox Version 5.4.0.0.

FLH, Federal Lands Highway. (2012). Project Development and Design Manual, Chapter 7 Hydrology and Hydraulics. Retrieved from https://flh.fhwa.dot.gov/resources/design/pddm/

NOAA. (2014). NOAA Atlas 14, Volume 6 Version 2.3: California.