Marchmont sewer detention tank construction and sewer upgrades

Forums Planning Applications Marchmont sewer detention tank construction and sewer upgrades

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    Grange Planning

      [Reposted from original entry on old forum on 19 September 2021]


      Planning application 21/04543/FUL has been submitted for consent to install a 3m high, 6.5m long green kiosk on Bruntsfield Links. This will house the Motor Controls for the pumps to be installed in the new sewage detention tank being built underground there. The application also seeks permission for a grasscrete access road, work to trees, and ground reprofiling.


      The site lies outwith the Grange Association area but many of our members will be concerned by this major project that will disrupt Bruntsfield Links during construction.


      Comments must be submitted by 15 October 2021.


      This is part of a project to alleviate the risk of flooding from sewers in Marchmont. It is a major construction project taking about 16 months. The underground works include a 20m diameter, 15m deep tank. The underground works do not require planning permission.


      What’s the problem that this is meant to solve?


      Edinburgh’s older sewers are ‘combined sewers’ and carry both:

      • the foul water from properties’ toilets and drains; and
      • the rainwater from roofs and roads.

      That means that, at times of heavy rainfall, the sewers can become overloaded and foul sewage can flood those properties that have the lowest drains in the area. This can create distressing flooding of properties with sewage coming back up the toilets and drains. Scottish Water is responsible for the sewer network and is required to maintain a register of properties that are at risk of internal flooding from sewers more than once in 30 years. It is then required to develop investment proposals that will remove those properties from the register. There is a separate register of external areas that are prone to flooding from overflowing sewers and an obligation to eliminate these also.


      Climate change is increasing the frequency of heavy rainfall and so more properties and external areas are likely to get added to the registers of those at risk from flooding from sewers at least once in 30 years unless investment in the sewer network can enable the periodic heavy flows to be accommodated without flooding. A property on the flooding register is likely to suffer in terms of property value, saleability and insurance. In parallel, changes are required to reduce the proportion of rainfall that ends up in the sewers, through better building standards (Sustainable Urban Drainage Systems) and planning control (e.g. not paving over gardens).


      What is the project intended to achieve?

      Scottish Water has developed a project to increase the volume of sewage that can be accommodated during heavy rainfall in Marchmont. Scottish Water will post updates on its project page as the project progresses. The project will remove:

      • 11 properties from the register of those at risk from internal flooding from sewers; and
      • three areas from the register of areas at risk from external flooding from sewers.


      What does the project involve?

      To achieve this, there will be new and upsized sewers installed in Marchmont Crescent and a short section of Marchmont Road to ensure that they can cope with high flows during heavy rain.


      The most significant construction, however, will be a large underground tank installed at the lowest point in the area – lower than any of the properties or areas to be removed from the risk of sewer flooding. This tank will provide short-term storage designed to accommodate the volumes expected in a 1 in 30-year rain storm. The tank will detain the water until the flows in the sewers subside sufficiently for the pumps in the new tank to pump the detained water back into the sewers for treatment downstream.


      The tank will be circular, formed from concrete rings, with a diameter of 20m and a depth of 15m. Its design capacity will be about 60% of the total volume, or 2,840m^3 of wastewater (slightly more than an Olympic swimming pool).


      There will also be a rectangular valve chamber built from brick 4.6m x 3.9m, to the southeast of the tank, about 3m deep.



      Where is this to be built?

      Marchmont sewer tank site

      The tank will be built at the eastern end of Bruntsfield Links, between Leamington Walk and Warrender Park Terrace.


      These are the site layout drawing and elevations.



      What will the site look like once the project is complete?

      The tank and valve chamber will be buried, with access covers, flush with ground level. Above ground, there will be a ‘grasscrete’ access road in a T-shape (“hammerhead”) to allow access for maintenance vehicles from Leamington Walk. Grasscrete is a pervious concrete mesh that allows grass to grow in the voids giving a generally green appearance.


      The most obvious structure, once the site has recovered after the construction works, will be the green Motor Control Centre (MCC). This will be a kiosk at the side of the footpath from Warrender Park Terrace. It will be 3m high, 6.5m long and 3m deep. A drawing is available here.


      There are already other utilities cabinets in this location, albeit much smaller than the kiosk proposed for this MCC.


      When will the construction works be taking place?

      Scottish Water estimates that the project will take 16 months to complete, with a projected start in early 2022 (subject to receiving the necessary consents).


      How much construction traffic will there be?

      During the works, construction traffic will access the site via Marchmont Road and Leamington Walk. There are between 15 and 20 traffic movements anticipated each day.


      Will there be diversions or road or path closures?

      A section of Leamington Walk will be closed for a period during the project to allow for vehicular access for the construction of the tank. A diversion will be put in place to maintain pedestrian and cycle access.

      Marchmont sewer tank construction path diversion


      The alternative route is shown in green. Proposals are still being discussed with the council.


      It is likely that there will also be restrictions on Marchmont Crescent during the works to upsize the sewers.


      What will this cost?

      £7 million


      Who is paying?

      Scottish Water’s investment programme is financed from the water and sewerage charges paid by domestic customers and business suppliers.


      What are the planning permissions required for?

      Scottish Water requires planning consent for the above ground works only. As a ‘statutory undertaker’, Scottish Water benefits from Permitted Development rights and so does not need planning permission for the upgrading of the sewers, the valve chamber, the 20m diameter tank or the access covers (which are flush with the ground).


      Planning permission is required, however, for the above ground proposals, specifically:

      • The Motor Control Centre (MCC) kiosk, on concrete foundations;
      • The ‘hammerhead’ grasscrete access road from Leamington Walk for permanent provision of maintenance access;
      • The work to the trees on Leamington Walk to facilitate access for construction equipment;
      • Ground reprofiling.


      Who has been consulted?

      Marchmont Sciennes Community Council and the Friends of Meadows and Bruntsfield Links have been consulted about these proposals.


      How can I comment?

      You can submit comments, on the specific aspects of this project that require planning permission, to the Council’s Planning portal, from the “Comments” tab at 21/04543/FUL, by 15 October 2021.


      You are also encouraged to add your comments (positive or negative) to this thread by adding a post below.

      Grange Planning

        [Reposted from old forum entry of 1 March 2022]


        The proposals have been modified:

        • There will be no vehicle access to the tank from Leamington Walk once the construction work is complete; instead a 12m x 3m tanker parking bay will be created in Warrender Park Terrace;
        • The ‘grasscrete’ access road will therefore not be required and is deleted from the proposals; the site will be restored to natural grass cover on completion, with the only exception being the four access covers to the tank which will be infilled with artificial grass;
        • Leamington Walk will remain open to pedestrians and cyclists throughout the construction work and no diversion will be required;
        • Instead of the one large 3m high, 6.5m long, kiosk on the Links, there will be two much smaller 1.8m high kiosks on Warrender Park Terrace, adjacent to the existing telecoms cabinets there.

        The contractors have provided this detailed drawing showing the revised proposed layout. A simplified version is shown below.

        Marchmont sewer tank - revised


        Planning permission 21/04543/FUL for the revised proposals was granted on 31 March 2022.

          Neil Robb

            Wow, Marchmont Crescent closing for 7 months. Thats a long time.


              Yes but only the bottom part which is a dead end opposite the Co-op ..

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