169138 — 23/10086/AIR | Planning Portal IoM

==== PAGE 1 ====

Purpose of issue:

APPROVAL

Document title:

Planning Condition Response Condition 15 Public Highway Surface Water Drainage

Document revision: S4-P1.0 Issue date: 11 Aug 23

4330100 King Gaming Campus, Douglas

==== PAGE 2 ====

Purpose of issue:

APPROVAL

Document title:

Planning Condition Response Condition 15 Public Highway Surface Water Drainage

Report Ref: PCR-C15 Created 11/01/23

Author: Rhys Jones Checked: David Hickman Signed:

Signed

Filing Ref: 3301-BSA-HDG-XX-FN-D-0001_PCR-C15

Creator: Rhys Jones, (Civil Engineer) [email protected]

Document revision: S4-P1.0 Issue date: 11 Aug 23

Document tracking:

Rev: Description: Issued by: Date: Checked: S2-P1.0 ORIGINAL ISSUE RLJ 13/01/23 DDH S3-P1.0 DRAFT ISSUE TO DISCHARGE PLANNING CONDITION RLJ 09/08/23 DDH S4-P1.0 ISSUE TO DISCHARGE PLANNING CONDITION RLJ 11/08/23 DDH

Version 2.9 4330100 King Gaming Campus, Douglas

==== PAGE 3 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Contents 1.0 Introduction & Purpose 2.0 Planning Condition 15 3.0 Response: Raised Pedestrian Crossing 4.0 Response: Development Thresholds 5.0 Conclusion Appendices A1 Drainage Overview Drawing

==== PAGE 4 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

1.0 Introduction & Purpose Burroughs Stewart Associates are engaged by Excel Construction Group as civil engineering works designers for the proposed King Gaming Campus, Douglas, Isle of Man. The existing site is a demolished brownfield site and is proposed to be developed into commercial offices, and two blocks of residential accommodation. A full planning application (Ref: 22/00549/B) for the proposed King Gaming Campus scheme was submitted to Isle of Man Government, on 13 May 2022. The application was originally determined on 22 November 2022, appeal determination on 29 June 2023 and a series of planning conditions accompanied the decision. This strategic note presents the applicant's response to Planning Condition 15 and outlines the route to discharging the condition. 2.0 Planning Condition 15 "Prior to commencement of any works, details shall be submitted in writing to the Planning Authority for approval which shows the surface water arrangements for the raised pedestrian crossing at the junction of Victoria Road and Switzerland Road. Further details showing how any surface water runoff from the proposed entrances will be prevented from draining onto the adjacent public highway and where such water will be drained to shall be included. The approved details shall be completed prior to the occupation of the development and maintain in working order." This condition relates to two specific elements. Firstly, the raised pedestrian crossing and secondly the drainage interface at the highway development boundary. These will be separately addressed below.

==== PAGE 5 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

3.0 Response: Raised Pedestrian Crossing As part of the development a raised pedestrian crossing is proposed across the junction of Switzerland Road as it joins Victoria Road to facilitate improvements to pedestrian safety. This facility will have no impact on the magnitude of impermeable area within the catchment and will therefore not increase the magnitude of existing surface water flows. The arrangement is shown in the following graphic.

Figure 3.1 - Proposed Raised Pedestrian Crossing A detailed topographical survey has been conducted of the area, which has been represented in contour form below.

Figure 3.2 - Existing Topographical Survey

==== PAGE 6 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Victoria Road falls from North to South with a central crown. On the approach of Switzerland Road, the central crown flattens out but maintains a North-South overland flow route. This existing surface water catchment from Victoria Road connecting to the nearest road gully in Switzerland has been analysed to be 316 square metres, as shown in the graphic below:

Figure 3.3 - Existing Surface Water Catchment There is currently potential for channel flow to turn down Switzerland Road (eastern junction quadrant). This overland flow route would become stopped-up with the installation of the raised pedestrian crossing. Surface water flows generated by Victoria Road will therefore be constrained to Victoria Road and approximately 51 square metres of existing surface water catchment will no longer enter Switzerland Road. The resultant proposed surface water catchment from Victoria and Switzerland Road junction has been analysed to be 265 square metres, as shown in the graphic below:

==== PAGE 7 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Figure 3.4 - Proposed Surface Water Catchments Introducing the raised pedestrian crossing would reduce drainage demand on the existing Switzerland Road road gullies by 16%. Further details on the raised pedestrian crossing and additional road gully can be seen on drainage overview drawing: 3301-BSA-S-XX-DR- D-0500-03_DrainageOverview in Appendix A1. It is our assertation that there should be no change to these gully utilisations because of the development, therefore a new gully is to be introduced to accommodate the 51m2 catchment that would have otherwise been conveyed elsewhere.

Figure 3.5 - Proposed Raised Pedestrian Crossing and Additional Road Gully

==== PAGE 8 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Figure 3.6 - Section A-A at Raised Pedestrian Crossing The crossing itself is expected to crown at the centre, shedding half its area in a north- westerly direction to Victoria Road, this is factored into the above assessment. The remainder of the crossing will flow south-easterly and re-join the existing south-easterly gradient along Switzerland Road.

==== PAGE 9 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

4.0 Response: Development Thresholds 4.1 Entrance 01 Proposed Entrance 01 is located on an existing site entrance/exit junction from Switzerland Road to facilitate access/egress immediately to Blocks A and B buildings, and onto the wider King Gaming development site. Detailed interrogation of the topographical survey and cross-referencing against the IOM Flood Risk Maps indicate there is a potential existing low elevation spot at the Site Access/Egress on Switzerland Road, approximately 40m from Victoria Road. The location is identified with a contour plot below:

Figure 4.1.1 - Entrance 01 Existing Topographical Survey The existing contributing catchment area from within the development plot, flowing out to the public highway at the proposed Entrance 01 has been analysed as 71 square metres and shown in the graphic below:

==== PAGE 10 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Figure 4.1.2 - Entrance 01 Existing Surface Water Catchment The new junction will rise from Switzerland Road and into the development site. Therefore, a small catchment will be generated and has the potential for additional catchment contributing to the public highway. The scheme would introduce two new road gullies at Entrance 01 and within the site boundary to intercept flows in this catchment area. Surface water flows generated will therefore be retained within the development site and approximately 50 square metres of existing surface water catchment will no longer enter Switzerland Road. Further details on the additional road gullies can be seen on drainage overview drawing: 3301-BSA-S-XX- DR-D-0500-03_DrainageOverview in Appendix A1. The resultant proposed surface water catchment entering Switzerland Road has been reduced to 21 square metres - a betterment of 70% - and shown in the graphic below:

Figure 4.1.3 - Entrance 01 Proposed Surface Water Catchments The remainder local catchments to Entrance 01 along Switzerland Road will remain unaltered and enter the existing highway drainage system. The identified low spot at the existing site access/egress will no longer exist due to improved impermeable paving surfacing and carriageway falls towards the existing highway drainage on Switzerland Road.

==== PAGE 11 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

4.2 Entrance 02 Proposed Entrance 02 is a new site entrance/exit junction from Switzerland Road to facilitate access/egress immediately to Blocks B and C buildings, and onto the wider King Gaming development site. At the location of proposed Entrance 02, existing trees and hedgerow form a soft verge between the development site and Switzerland Road where collected surface water can enter without hard kerb obstruction. Infiltration would be limited, and overland flows would continue to low elevations. The Entrance 02 location is identified with a contour plot below:

Figure 4.2.1 - Entrance 02 Existing Topographical Survey The new junction will rise from Switzerland Road and into the development site. Therefore, a small catchment will be generated and has the potential for additional catchment contributing to the public highway surface water drainage network. To avoid additional surface water flows entering Switzerland Road, the scheme would introduce two new road gullies and a minimum 40mm high speed hump at Entrance 02 to intercept and direct existing channel flows away from the public highway and into the development site. This surface water catchment of 54 square metres will therefore be controlled and managed by the scheme. Further details on the additional road gullies and speed hump layout can be seen on drainage overview drawing: 3301-BSA-S-XX-DR-D- 0500-03_DrainageOverview in Appendix A1. The graphic below shows the surface water catchment from Entrance 02 to be controlled and managed by the scheme:

==== PAGE 12 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Figure 4.2.2 - Entrance 02 Proposed Surface Water Catchment Existing gradients and local catchments to Entrance 02 along Switzerland Road will remain unaltered and perform to the current arrangements and enter the surface water network.

==== PAGE 13 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

4.3 Entrance 03 Proposed Entrance 03 is a new entrance/exit junction to the site from Switzerland Road to facilitate access/egress immediately to Block C building basement. At the location of proposed Entrance 03, existing trees and hedgerow form a soft verge between the development site and Switzerland Road where collected surface water can enter without hard kerb obstruction. Infiltration would be limited, and overland flows would continue to flow to lower elevations. The Entrance 03 location is identified with a contour plot below:

Figure 4.3.1 - Entrance 03 Existing Topographical Survey Detailed interrogation of the topographical survey of Switzerland Road indicates an existing catchment of 226 square metres that gathers near the proposed location of Entrance 03, as shown in the graphic below:

==== PAGE 14 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Figure 4.3.2 - Entrance 03 Existing Surface Water Catchment The new junction will fall from Switzerland Road and into the development site. A flood risk of overland flows entering the Block C Building basement would remain and a physical barrier is required to intercept surface water flows. Development proposals at Entrance 03 require a ramped access down into the basement car park. Further details on the additional channel drain and speed hump layout can be seen on drainage overview drawing: 3301- BSA-S-XX-DR-D-0500-03_DrainageOverview in Appendix A1. To avoid existing surface water flows from Switzerland Road entering the development site and flooding the Block C Building basement car park, the scheme would introduce a minimum 40mm high speed hump at the Entrance 03 threshold to intercept flows and maintain flows on Switzerland Road. Surface water captured on the proposed access ramp shall be collected in a 200mm wide channel drain and managed by the development. These proposals are shown in the graphic below:

Figure 4.3.3 - Entrance 03 Proposed Surface Water Catchment

==== PAGE 15 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

120 square metres of collected surface water flows in this ramp area will be managed by the development. Existing gradients and local catchments to Entrance 03 along Switzerland Road will remain unaltered and perform to the current arrangements.

==== PAGE 16 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

5.0 Conclusion The scheme removes some of Victoria Road catchment into Switzerland Road via a new gully into the existing below ground public drainage, reduces the existing private catchment entering the public highway and maintains segregation of private and public drainage catchments, whilst also protecting the King Gaming campus from flood risk from the public highway. The scheme would be removing a total of 101 square metres of surface water flows to the Switzerland Road catchment at the Raised Pedestrian Crossing and Entrance 01, respectively. These improvements to surface water catchments are seen as wider benefits to the King Gaming scheme and would only enhance the existing arrangement, positively affecting existing surface water flood risk on Switzerland Road.

==== PAGE 17 ====

4330100 - King Gaming Campus, Douglas

PCR-C15 - Planning Condition Response Condition 15 Public Highway Surface Water Drainage

August 23

3301-bsa-hdg-xx-fn-d-0001_planningconditionresponse-condition#15

Appendix A1 Drainage Overview Drawing

==== PAGE 18 ====

LEGEND: PROPOSED SURFACE WATER ATTENUATION TANK PROPOSED SURFACE WATER PIPE PROPOSED HIGHWAY GULLY EXISTING PRIVATE SURFACE WATER CULVERT EXISTING GLEN WATERCOURSE PROPOSED SURFACE WATER CHANNEL DRAIN PROPOSED SURFACE WATER FLOW CONTROL MANHOLE CHAMBER EXISTING SEWER NETWORK SECTION TO BE ABANDONED AND REMOVED PROPOSED FOUL WATER PIPE PROPOSED FOUL WATER MANHOLE CHAMBER LEGEND: EXISTING COMBINED SEWER EXISTING SEWER MANHOLE CHAMBER PROPOSED 150mmØ PERFORATED PIPE EXISTING MUA SURFACE WATER SEWER PROPOSED MUA SURFACE WATER DIVERSION PIPE PROPOSED MUA SURFACE WATER MANHOLE CHAMBER PROPOSED SURFACE WATER SOAKAWAY PROPOSED SURFACE WATER FILTER DRAIN EXISTING SEWER CHAMBER TO BE ABANDONED AND REMOVED LEGEND: LEGEND: PROPOSED SURFACE WATER CHAMBER NGR EASTING: NGR NORTHING: 238850 477156 Chair Lift SM SM 531991 Athol Terrace Erin Brae 38 26 49 37 14 13 1 25 Piccadilly Court VICTORIA ROAD SWITZERLAND ROAD 48.79 SWITZERLAND ROAD DRAWING NOTES: 1. THIS DRAWING IS TO BE READ IN CONJUNCTION WITH ALL OTHER BURROUGHS STEWART ASSOCIATES CIVIL ENGINEERING DRAWINGS. 2. DRAINAGE LAYOUT SHOWN BELOW IS SUBJECT TO CHANGE PENDING DEVELOPING PROPOSED FINISHED LEVELS AND APPROVAL FROM THE LOCAL PLANNING AUTHORITY. 3. UNLESS OTHERWISE STATED INSTALLATION IS TO BE IN ACCORDANCE WITH BUILDING REGULATIONS, APPROVED DOCUMENT H. 4. PIPEWORK MATERIAL TO BE IN ACCORDANCE WITH MANX SEWERS FOR ADOPTION 1ST EDITION. 5. ALL CIVIL ENGINEERING WORKS TO BE CONSTRUCTED AND INSTALLED IN ACCORDANCE WITH CIVIL ENGINEERING SPECIFICATION FOR THE WATER INDUSTRY 7TH EDITION, MANX SEWERS FOR ADOPTION 1ST EDITION AND DESIGN MANUAL FOR ROADS AND BRIDGES - VOLUME 4, SECTION 2. 6. PROPOSED DRAINAGE BASED ON TOPOGRAPHICAL, UTILITIES AND CCTV DRAINAGE SURVEY INFORMATION. 7. ALL PROPOSED MANHOLES AND CHANNEL DRAINAGE IN VEHICLE LOADED AREAS TO BE LOAD CLASS: D400 UNLESS OTHERWISE STATED. 8. ALL PROPOSED MANHOLES AND CHANNEL DRAINAGE IN NON-VEHICLE LOADED AREAS TO BE LOAD CLASS: A15 UNLESS OTHERWISE STATED. 9. ALL ROAD GULLY OUTFALL PIPES TO BE 150MM NOMINAL DIAMETER. 10. APPROPRIATE PROPOSED CONNECTIONS TO EXISTING SEWERS TO BE AGREED IN ADVANCE OF CONSTRUCTION. 11. CONTRACTOR IS TO ARRANGE ALL TRAFFIC MANAGEMENT AND TEMPORARY WORKS REQUIREMENTS. 12. REFER TO DRAINAGE DETAILS FOR MORE INFORMATION. 13. DESIGNED SURFACE WATER STORAGE REQUIREMENTS DO NOT CONSIDER BROWN ROOF STORAGE CAPACITIES AND TO BE CONFIRMED WITH M&E ENGINEER. BLOCK C BUILDING BLOCK B BUILDING BLOCK A BUILDING ENTRANCE 01 ENTRANCE 02 ENTRANCE 03 RAISED PEDESTRIAN CROSSING AT VICTORIA/SWITZERLAND ROAD JUNCTION Date: Date: Drawn By: Checked By: Approved By: Designed By: Date: Date: 10 cm - Caution as distortion can occur. 10cm - Caution as distortion can occur. ALL CIVIL DIMENSIONS ARE IN METRES - ALL STRUCTURAL DIMENSIONS ARE IN MILLIMETRES - ALL LEVELS ARE IN METRES. Revision: Status Description: Revision Description: Drawing Number: This document is copyright of BSA. Use figured measurements only! DO NOT SCALE FROM DRAWING. Verify all dimensions prior to construction. Immediately report any discrepancies to BSA and if in doubt ASK. This drawing should be read inconjunction with all other associated project information Project: Drawing Title: A1 Original Paper Size: REV. DATE CHK. DRW. 17A Victoria Street, Douglas, Isle of Man IM1 2LW | Telephone: (01624) 662 155 Facsimile: (01624) 662 141 | www.bsa.co.im PRELIMINARY KING GAMING CAMPUS, DOUGLAS 03 ISSUE TO DISCHARGE PLANNING COND. SERIES 0500 - DRAINAGE OVERVIEW - GENERAL ARRANGEMENT 3301-BSA-S-XX-DR-D-0500 RLJ SL RLJ DDH 06/04/23 06/04/23 06/04/23 06/04/23 CONSULTING CIVIL AND STRUCTURAL ENGINEERS BURROUGHS STEWART ASSOCIATES 50m 5m 10m 15m 20m 25m 30m 35m 40m 45m SCALE BAR 1:500 01 BUILDING CONTROL ISSUE 06/04/23 SL RLJ 02 DRAFT ISSUE TO DISCHARGE PLANNING CONDITIONS 08/08/23 RLJ NW 03 ISSUE TO DISCHARGE PLANNING CONDITIONS 11/08/23 RLJ NW

==== PAGE 19 ====

bsa.co.im

17A Victoria Street DOUGLAS Isle of Man IM1 2LW T: (01624) 662155 F: (01624) 662141 E: [email protected]

Associated Office in Cardiff Burroughs Stewart Associates is the trading name of Burroughs Stewart Associates Limited. Directors: A.C. Burroughs, P.O. Burroughs, G. Leach Registration No: 059958C. VAT Registration No: 001 0485 41