Appendix 1 - Blairgowrie & Rattray SWMP - Plans of Short Listed Potential Options
Perth and Kinross Council · 23 October 2024
Back to Climate Change and Sustainability Committee — 23 October 2024 and its agenda
Text extracted from the council's PDF. Layout and reading order may differ from the original.
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Appendix 1 Blairgowrie & Rattray Surface Water Management Plan (SWMP) – Plans of Short Listed Potential Options Option A Surface water diversion (speed hump) at Upper Allan Street This was the top scoring option from the multi-criteria assessment. It is a simple speed ramp, placed on Upper Allan Street. The rationale behind this is to intercept overland flow that currently causes some of the flood risk experienced in Blairgowrie town centre and direct it into Cuttle Burn Den which will naturally enable it to flow towards the River Ericht away from buildings in the town. Figure 1 indicates on a map where this feature would be sited. Figure 1 – Surface water diversion (speed hump) at Upper Allan Street (Option A)
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Option B Leaky Dams / Natural Flood Management on the Rattray Burn This option scored 2nd place in the multi-criteria assessment. The rationale behind this is to hold water further up in the Rattray Burn catchment releasing it slowly to keep it within the capacity of the Rattray Burn channel for as long as possible thus reducing the amount of time it spills out-of-bank towards the urban area of Rattray. Figure 2 indicates on a map where these features could be sited. Figure 2 – Surface water diversion (speed hump) at Upper Allan Street (Option B)
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Option C Disconnection of the industrial area at Welton Road from the combined sewer network This option scored 3rd place in the multi-criteria assessment. The rationale behind this is to redirect surface water runoff out of the combined sewer into an open pond to treat it prior to discharge into the River Ericht. This increases the combined sewer capacity upstream reducing the surface water flood risk in Blairgowrie town centre. Figure 3 indicates on a map where this features could be sited. Figure 3 – Disconnection of the industrial area at Welton Road from the combined sewer network (Option C)
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Option D Construction of SuDS on Rattray Common This option scored 4th place in the multi-criteria assessment. The rationale behind this is to direct excess flows from the Rattray Burn and route them to a new SuDS facility in Rattray Common prior to discharge to Loon Braes. A high volume of water is estimated to be required for storage/attenuation but the storage for this can be split between Rattray Common, Loon Braes and potentially to an expanded SuDS facility at David Grimmond Place (subject to agreeing use of land). Figure 4 indicates on a map where the features could be sited. It is important to note that the proposals at feasibility study stage are primarily to understand if the option is viable, and that the final form of an intervention of this size can be a community driven design and sometimes involves other aspects such as landscape architecture and/or active travel routes depending on other local aspirations. Figure 4 – Construction of SuDS on Rattray Common (Option D)
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Option E Construction of a swale behind Burnhead Road This option scored 5th place in the multi-criteria assessment. The rationale behind this is to collect overland flow in a small ditch from steep fields behind Burnhead Road and direct it towards the Cuttle Burn Den so it can then naturally flow into the River Ericht and away from properties. Figure 5 indicates on a map where this option could be sited. Figure 5 – Construction of a swale behind Burnhead Road (Option E)