RWDI Unit 1 Tilers Road Milton Keynes Buckinghamshire MK11 3LH United Kingdom Email: [email protected] Tel: +44 (0)1908 776970 Fax: +44 (0)1582 470259 Bromley-By-Bow South London, United Kingdom Final Report Pedestrian Level Wind Microclimate Assessment RWDI # 1601191-PLW April 21st, 2016 SUBMITTED TO SUBMITTED BY Vanessa Buckland Krishan Jayyaratnam AECOM Environment and Planning Project Engineer St Georges House, [email protected] 5 St Georges Road, Wimbledon, Ender Ozkan London, UK Regional Manager SW19 4DR [email protected] Stefan Astley [email protected] Project Manager [email protected] This document is intended for the sole use of the party to whom it is addressed and may contain information that is privileged and/or confidential. If you have received this in error, please notify us immediately. ® RWDI name and logo are registered trademarks in Canada and the United States of America Reputation Resources Results Canada | USA | UK | India | China | Hong Kong | Singapore www.rwdi.com Bromley-By-Bow – London, United Kingdom Pedestrian Level Wind Microclimate Assessment RWDI#1601191 April 21st, 2016 TABLE OF CONTENTS Executive Summary ............................................................................................................................................ 1 1. Introduction ................................................................................................................................................. 2 2. Site Description ........................................................................................................................................... 2 2.1 Site Location and Surroundings ............................................................................................................ 2 2.2 Illustrative Masterplan ........................................................................................................................... 3 3. Procedure and Methodology ..................................................................................................................... 4 3.1 Simulation of Atmospheric Winds ......................................................................................................... 4 3.2 Measurement Technique ...................................................................................................................... 4 3.3 Scaling .................................................................................................................................................. 4 3.4 Meteorological Data .............................................................................................................................. 4 3.5 Pedestrian Comfort ............................................................................................................................... 4 3.6 Strong Winds ........................................................................................................................................ 5 4. Results ......................................................................................................................................................... 5 4.1 Details of the Analysis ........................................................................................................................... 5 4.2 Desired Pedestrian Activity around the Illustrative Masterplan ............................................................ 5 4.3 Performance against Criteria ................................................................................................................ 5 4.3.1 Configuration 1: Existing Site with existing surroundings ................................................................ 5 4.3.2 Configuration 2: Illustrative Masterplan with existing surroundings ................................................ 6 4.3.3 Configuration 3: Illustrative Masterplan with cumulative surroundings ........................................... 6 4.4 Occurrences of Strong Winds ............................................................................................................... 8 5. Mitigation Measures ................................................................................................................................... 9 6. Further Considerations for Detailed Design and Future Planning Applications ............................... 10 7. Concluding Remarks ................................................................................................................................ 10 Reputation Resources Results Canada | USA | UK | India | China | Hong Kong | Singapore www.rwdi.com Bromley-By-Bow – London, United Kingdom Pedestrian Level Wind Microclimate Assessment RWDI#1601191 April 21st, 2016 VERSION HISTORY Index Date Pages Author A April 18th, 2016 All K. Jayyaratnam st 1-3, 5-7, 9, B April 21 , 2016 K. Jayyaratnam 10 Checked by: E. Ozkan Reputation Resources Results Canada | USA | UK | India | China | Hong Kong | Singapore www.rwdi.com Bromley-By-Bow – London, United Kingdom Pedestrian Level Wind Microclimate Assessment RWDI#1601191 April 21st, 2016 Page 1 desired locations highlighted in Configuration 2 remain in Configuration 3; therefore mitigation measures EXECUTIVE SUMMARY described for these locations will remain effective in the cumulative scenario. The objective of this study was to determine the ground, podium and roof terrace level wind environment and Overall, the wind microclimate around the Illustrative Masterplan is largely acceptable for its intended use and assess the acceptability of the wind microclimate around the illustrative masterplan of the Bromley by Bow any windier than desired locations are expected to be mitigated by the measures described in this report. (South) site (‘the Site’) as allocated by the LLDC Local Plan 2015 to 2031, Sub Area 4.1, , in regards to both It is highly recommended that for later detailed design associated with any future planning application for the pedestrian comfort and safety. This report will sit alongside the illustrative masterplan and a suite of Site, or any part thereof, further wind tunnel testing should be undertaken to ensure that the wind microclimate Environmental Impact Topic Reports as the evidence base to a Supplementary Planning Document to be is consistent with the finding of this report and assess balcony locations and any design changes made. adopted by the LLDC, which sets out the maximum parameters for redevelopment of the Site. This report presents a description of the methodology used and the results of 3 configurations tested in the wind tunnel, namely: • Existing Site with existing surrounding buildings (‘the ‘Baseline’); • Illustrative Masterplan with existing surrounding buildings; and • Illustrative Masterplan with cumulative surrounding buildings Results are presented in terms of the Lawson Comfort Criteria, with the main focus on the windiest (generally winter) and summer season conditions. The existing Site with existing surrounding buildings has conditions acceptable for a range of uses from sitting to leisure walking use. This range of conditions is fairly typical of a predominantly low to mid-rise urban area such as London. In the presence of the Illustrative Masterplan, the wind microclimate in and around the Site is similar to that of the Baseline. Areas close to the taller, southern blocks of the Illustrative Masterplan are windier than areas to the north-east which are sheltered by the Illustrative Masterplan. Overall wind conditions range from acceptable for sitting to leisure walking use during the windiest season except at one location, off-site (east of the No 1 The Plaza development to the south-west of the Site), which observes business walking conditions and occasional strong winds above Beaufort Force 7. In the baseline scenario wind conditions at this location were at the upper end of leisure walking range with Beaufort Force 6 winds. This is mainly due to the aerodynamic effect of the No 1 The Plaza on this area. When the Illustrative Masterplan is in situ, there is a slight increase in wind speeds which causes the conditions at this location to change from leisure walking to business walking in the windiest season, in combination with Beaufort Force 7 winds. In the detailed design stage, adjustments to the Illustrative Masterplan or off-site landscaping will be effective in reducing wind speeds at this location. The majority of thoroughfare locations and entrances experience the desired wind condition for their intended uses during the windiest season. Two building entrances within the Illustrative Masterplan experienced windier than desired wind conditions. Localised landscaping around the entrance (such as small trees, shrubs in planters, porous screens etc.) or recessing the entrance 1.5m will be effective in reducing wind speeds at the entrance to the desired wind condition. Ground level amenity spaces experienced the required wind conditions during the summer season. This is largely as a consequence of the beneficial podium design of the Illustrative Masterplan. The podiums help to ‘catch’ the down-draughting flow from the taller blocks, and prevent it from reaching the ground level. This beneficial design feature should be retained in the detailed design stage. On the other hand, catching the downdrafts the podiums themselves can become windy areas. Localised landscaping within some of the terraces (soft or hard landscaping) will be effective in reducing wind speeds for occupants comfort. Additionally, roof terraces