South Cambridgeshire District Council - Groundworks and drainage : Northstowe Phase 1 Allotments

Tender description

<p>The Council seeks a contractor to perform the following: Develop a proposal and recommendations for deep ripping and a field drainage solution to remediate water-logging on the Northstowe Phase 1 Allotment and orchard site. Proposals should include recommendations in the Soils Investigation Report (see Appendix 1). The allotment site is made up of placed topsoil from the Northstowe development site. The placed topsoil varies in depth from approximately 300mm to over 1200mm. Bidders are asked to put forward proposals (submitted with the tender), for deep soil ripping and drainage including the equipment to be used. The proposals shall also include the sequence of work. The bidders will be expected to make themselves familiar with the site. Accompanied site visits and contact with Council representative are encouraged. Please note no topographical survey of the accurate final levels of the Allotments (a mainly flat site) is available, but we have included a survey of the site immediately to the south is included with this tender pack &ndash; the site to the south is at the same finished level. The proposals shall be approved prior to commencement and should include: a) Conduct a series of filtration trial holes to ascertain drainage properties of original ground below placed topsoil and report findings. See e) below. b) Deep rip soil to depth of at least 600mm at 600mm centres. c) Cultivate top 300mm of topsoil. d) Install a field drainage system to allotment and orchard site. Sequencing and appropriate equipment to be recommended so as not to compact the decompacted soils. e) Assess and recommend location(s) for an on-site drainage feature such as one or more French drains excavated into the original ground into which the land drainage will connect and drain. An overflow outfall from this feature to nearby existing drainage connection points options (See Appendix 2) should also be included (connection points to be verified by the bidder). All calculations for draining the allotment area, as well as runoff storage and overflow capacity, to be the responsibility of the bidder. Calculations for drainage to be supplied to the Council on appointment. f) Preserve existing water supply and troughs (pipework and trough locations to be verified on site by Contractor prior to work starting), hard landscape, fencing and make good any damage to this infrastructure (see Appendix 3). Please note that the community orchard element of the landscape design has not yet been implemented but the area is to be included within the quotation. g) Clear access will be available to the whole allotment area from the northern end of the site from Station Road, Longstanton and through the proposed Community Orchard area (Appendix 4). The plots will be cleared to allow clear access to the land. h) Any spoil to be taken off site and disposed of in a licenced tip. i) Plots to be re-pegged out and all grass paths to be reinstated with turf. Areas not under cultivation such as the southwest corner of the site to be sown with Phacelia. Allow for temporary protective fencing of turfed areas and watering to ensure establishment. The maps below show the site location within the wider Northstowe development. To the west of the site runs a bridleway (shaded blue on the plan attached). Public access along this Right of Way must not be compromised and due care and attention paid to members of the public who may be using this Right of Way whilst works are undertaken. All on-site work must be completed within the hours 8am - 6pm. Monday - Friday and 8am - 1pm Saturday and at no time on Sundays, Bank or Public Holidays, unless agreed in writing by the Local Planning Authority. Works to be carried out when soil has dried out and no works to be carried out in wet weather.</p> Keywords: groundworks and drainage