APL Planning Statement

Glen Rd Laxey Retaining wall Statement of Case

December 2020

Contents

• 1 Background......................................................................................................3
• 2 Glen Road Laxey Retaining Wall Proposals..........................................................3
• 3 Conclusion.......................................................................................................4
• 4 Appendix .........................................................................................................4

• 4.1 Drawings ..................................................................................................................4
• 4.2 Photographs .............................................................................................................4

• 1 Background On the 1st October 2019, following a severe flood event in the Village of Laxey 62 properties experienced flooding. The area most affected was Glen Road where 51 of the 62 flooded properties are located. This report provides details of repairs implemented and proposed for a section of river wall which acts as a boundary between Glen Road highway and Laxey River. The high river levels resulting from the flood event were further exasperated by flood waters entering Glen Road via the gap created in the highway wall to allow access for the construction of a fish pass and debris build up behind the MER weir structure which resulted in elevated river levels upstream of the weir. All of these factors resulted in overtopping of the highway wall adjacent to Glen Road as a result of the elevated upstream levels and collapse of the highway wall immediately upstream of the MER weir, which resulted in sudden inundation of Glen Road and subsequent flooding to a lot of the properties on Glen Road.
• 2 Glen Road Laxey Retaining Wall Proposals Immediately after the flood levels abated the Department of Infrastructure swiftly proceeded, with emergency actions, to remove debris material from the river and carry out demolition of failed sections of the Glen Road retaining wall. The failed sections of the wall were then reconstructed in reinforced concrete approximately 300mm higher than the original wall to give additional protection from flooding. For aesthetics the wall was then faced in Manx stone.

The section of retaining wall to be replaced initially was from Ballacowin Cottage on Glen Road up to the road bridge at Laxey Woolen Mills, an approximate length of 140 metres. Appendix A presents a location plan of the various different sections of wall under review. The first section of retaining wall already completed is depicted in magenta on the location plan and the construction details are shown in Section A-A. This completed section of works incorporates a flood gate to provide access to the river for maintenance purposes as requested by DEFA and MUA. The next upstream section of 25m is an existing masonry wall which it is proposed to demolish and replace down to river bed level in the same manner as shown in Section A-A. The next 67m of wall already has a reinforced concrete lining below road level and so it is proposed to demolish the wall to road level only and construct a new reinforced concrete boundary wall above road level. The construction details of this wall type are shown in Appendix A, Section B-B. The remaining section for replacement has 18m of Manx stone wall and 13m of railings up to the bend at the bridge. The wall below carriageway has no concrete face so it is proposed to provide a new reinforced concrete lining on the river side up to road level. A new reinforced concrete

boundary wall would then be constructed above this. Construction details for this are shown in Appendix A, Section C-C. There is an additional section of wall opposite the properties of Hollywood and Acacia Villa that also need strengthening. These are to be raised approximately 900mm to the same height as the rest of the wall with additional reinforced concrete up stands on top of the existing as shown in Appendix A, Section D-D.

• 3 Conclusion This report concludes that the remaining sections of wall should be replaced in accordance with the proposals outlined in this report as soon as possible to prevent any future breaches of the cell comprising the river wall on Glen Road. All of the new walls are to be constructed higher than the original wall to a level recommended by MUA to reduce the likelihood of future flooding.
• 4 Appendix

• 4.1 Drawings
• 4.2 Photographs

Repair Shop

Muir Terrace

Workshop

Newstead

Mauna Kea

Bridge House Mill House

Community

Centre

El Sta

Weir

Weir

Laxey Woolen Mill

Sub

13m of existing railings to be replaced with new wall from carraigeway level and new concrete face to lower level.

18m of existing wall type 1 to have new wall from carraigeway level and new concrete face to lower level.

Path (um)

Path (um)

Garage

Garage

Mona Villa

Villa

Ballabeg

Bank

Corvette

Ruskinville

Fy Yerrey

LB

LB

Riverside House

House

Shelter

Town

Hall

Mylroie House

Existing wall type 2 to be replaced with 67m of new wall from carraigeway level.

PC

Ballashalom

Glen Royal

Laxey Dental Practice

25m of new wall down to river bed level

Car Shed

GLEN ROAD

Wall down to river bed level (already constructed) Glen Grawe Cottage Flood gate (already constructed) Glen GraweHouse

House

Wall down to river bed level (already constructed)

Weir

Weir

Garykellie

Cottage

Cottage

Dove Cottage

Sunny Glen

Existing wall types 3 & 4 to be strengthened and raised

Fern Villa

Hillside

Hillside

Hollybank

Area U/C

Fuchsia Cottage

Cottage

Cottage

Roslyn

Fairholme

Hawthorn

Cottage

Cottage

High

View

Dhoon Villa

Villa

Candle Cottage

Queens Hotel

(PH)

Stakhanovite House

House

Braeside

Edgeworth

Osborne Cottage

Car

Park

Garage Adj Queens Hotel

Weir

Weir

Hillside

Hillside

Weyham

The Haven

Nirvana

RAMSEY ROAD

Prospect House

Ballakneale

Westroyd

Delphinus

Creggans

The

The

Spring

House

House

Path (um)

Path (um)

Sunny Brae

Garage

Garage

The Manx Electric Railway

Ballacowin Cottage

Cottage

Mannin Cottage

Hollywood

Acacia Villa

Villa

Spring Villa

Glen Side

Veg Veen Cottage

Verndale

LB

LB

Victoria Terrace

Rough

Lea

Lossan Y Twoaie

Weir

Weir

The

The

Braes

Works

Stream Cottage

Cottage

Sycamore

Cottage

Cottage

Thie Maynrys

Ref. Revision Date By Chk.

AMENDMENTS

Status<br><br>Draft

infrastructure<br><br>bun-troggalys<br><br>

	Client:Highways
<br><br>QUO<br><br>BIT<br><br>Government<br><br>Isle of Man<br><br>Engineering Design<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>T/DT/A1/01
---

Job Title<br><br>Laxey Glen Road Flood Wall

Drawing Title<br><br>Location Plan

Drawn By

Date

Oct '19 1 : 500

GSm AMC

Checked By

Scale

Rev.

Job Ref Drawing No

Flood level + freeboard 19.975 Flood design level 19.672 Top of existing wall varies (approx. 19.660)

Note: Flood design levels are based on 1:100 year modelled levels

13801400

Existing road level 18.280 Existing Manx stone wall Existing bed level 16.880 Section Through Existing Wall Type 1

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Existing Wall Type at section B - B

Drawn By

G.Sm

Date

Aug '20

1 : 25

Checked By

Scale

AMC

Job Ref Drawing No

Fw/101

Rev.

Flood level + freeboard 19.975

80 500

Flood design level 19.672

Top of existing wall varies (approx. 19.660)

Note: Flood design levels are based on 1:100 year modelled levels

Existing road level 18.280 Existing concrete facia Existing Manx stone wall A393 reinforcing mesh with 50mm cover. Existing bed level 16.880 Section Through Existing Wall Type 2

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Existing Wall Type at section C - C

Drawn By

G.Sm

Date

Aug '20

1 : 25

Checked By

Scale

AMC

Job Ref Drawing No

Fw/102

Rev.

approx. 19.975

1600 (proposed wall design height) Manx stone to be fixed to face and top of concrete wall on the highway elevation. 3.0m high pre-cast concrete retaining wall units Existing road level

20mm of AC 6 dense surface course on 40mm of AC 20 dense binder course on 100mm granular Sub-base Type 1 Unbound Material in accordance with S.H.W. (August 2008) Clauses 1105 and 803.

Type 1 backfill 300mm dia. drainage pipe Existing bed level

Precast unit pinned to concrete base with 4 No. 30mm Fosroc bolts, as per manufacturers instructions. Base to be cased with 300mm C32/40 concrete

A393 reinforcing mesh with 50mm cover.

Section A - A

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Proposed Section A - A Top of Glen Road

Drawn By

G.Sm

Date

Aug '20

1 : 25

Checked By

Scale

AMC

Job Ref Drawing No

Fw/103

Rev.

approx. 19.975

345 Level to top of existing wall varies

Manx stone to be fixed to face of concrete with 3 no. stailess steel wall ties /m² and returned over top of existing wall to bring total height of wall up to 1600mm.

Existing wall height 1.75m high pre-cast concrete retaining wall units Precast unit pinned to concrete base with 30mm Fosroc bolts, as per manufacturers instructions. Base to be C32/40 concrete Existing road level

235300

A393 reinforcing mesh with 50mm cover. Existing concrete facia Existing Manx stone wall Existing bed level

Section B - B

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Proposed Section B - B Top of Glen Road

Drawn By

G.Sm

Date

Aug '25

1 : 20

Checked By

Scale

AMC

Job Ref Drawing No

Fw/104

Rev.

approx. 19.975

345 Level to top of existing wall varies

Manx stone to be fixed to face of concrete with 3 no. stailess steel wall ties /m² and returned over top of existing wall to bring total height of wall up to 1600mm.

Existing wall height 1.75m high pre-cast concrete retaining wall units Precast unit pinned to concrete base with 30mm Fosroc bolts, as per manufacturers instructions. Base to be C32/40 concrete Existing road level

235300

Existing Manx stone wall A393 reinforcing mesh with 50mm cover. Concrete face to be added to the existing Manx stone wall. A393 reinforcing mesh with 50mm cover. Existing bed level

Section C - C

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys<br><br>

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Proposed Section C - C Top of Glen Road

Drawn By

G.Sm

Date

Aug '20

1 : 25

Checked By

Scale

AMC

Job Ref Drawing No

Fw/105

Rev.

Flood level + freeboard 19.975

H16 resin anchors with min. 300mm embedment into top of existing wall @ 200c/c with H10 lacer bars @ 300c/c horizontally. Provide 75mm cover.

900700

C32/40 concrete extension to wall Existing 440mm thick concrete wall Section D - D Wall type 3

Notes

Ref. Revision Date By Chk. AMENDMENTS

Status

infrastructure<br><br>bun-troggalys<br><br>

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Proposed Section D - D Top of Glen Road

Drawn By

G.Sm

Date

Aug '20

1 : 25

Checked By

Scale

AMC

Job Ref Drawing No

Fw/106

Rev.

Notes

Flood level + freeboard 19.975 A393 mesh with min. min. 600mm lap onto starter bars H16 resin anchors with min. 300mm embedment into center top of existing wall @ 200c/c with H10 lacer bars @ 300c/c horizontally. Ref. Revision Date By Chk. AMENDMENTS Existing 200mm thick concrete wall

Status

H16 starter "L bars" @ 200c/c with H10 lacer bars @ 250c/c horizontally. Provide 50mm cover

infrastructure<br><br>bun-troggalys

250250

	Client:MUA
<br><br>QUO<br><br>QUE<br><br>CUN<br><br>CER<br><br>IS<br><br>JE<br><br>STA<br><br>BIT<br><br>Reiltys Ellan Vannin<br><br>Government<br><br>Isle of Man<br><br>Highway & Asset Management<br><br>Highway Services Division Department of Infrastructure First Floor, Sea Terminal Building, Douglas Isle of Man, IM1 2RF<br><br>Telephone: (01624) T/DT/A4L/01
---

Existing block paving to be taken up locally and replaced on a 50mm sand bed after construction of wall footing.

Job Title<br><br>Flood Wall<br><br>Laxey Glen Road

Drawing Title<br><br>Proposed Section E - E Top of Glen Road

Section E - E Wall type 4

Drawn By

Date

Aug '20

G.Sm

1 : 25

Checked By

Scale

AMC

Rev.

Job Ref Drawing No

Fw/107

Wall breach at top of Glen Road due to MUA weir upper work

Wall breach upstream of lower weir due to blockage at weir and deliberate wall breach downstream of weir to allow water back into river

Blockage to lower weir causing wall breach

Change in wall type between Section A-A and Section B-B

Damage to existing Manx Stone wall at Section B - B