--- title: "Reservoir Safety Improvement Works" ocid: "ocds-kuma6s-161799" canonical_url: "https://d3tenders.com/contract/?ocid=ocds-kuma6s-161799" markdown_url: "https://d3tenders.com/contract/ocds-kuma6s-161799.md" json_url: "https://d3tenders.com/contract/ocds-kuma6s-161799.json" source: "Sell2Wales" current_stage: "Tender" buyer: "AWDURDOD PARC CENEDLAETHOL ERYRI" published: "2026-02-20" --- # Reservoir Safety Improvement Works Buyer: AWDURDOD PARC CENEDLAETHOL ERYRI Current stage: Tender OCID: ocds-kuma6s-161799 [View canonical contract page](https://d3tenders.com/contract/?ocid=ocds-kuma6s-161799) [Download OCDS JSON](https://d3tenders.com/contract/ocds-kuma6s-161799.json) ## Summary The Awdurdod Parc Cenedlaethol Eryri is inviting tenders for the Reservoir Safety Improvement Works at the Llyn Mair Reservoir in Eryri National Park, Gwynedd. The procurement falls under the works category and is conducted via a limited method. Interested parties must note that the planning involves installing a new siphon pipe to manage water levels during emergencies and modifying existing spillways. The project deadline is set for 31st July 2026, with the tender submission concluding at 12:00 on 9th March 2026, followed by an award period ending on 14th April 2026. The procurement documents are available online, accessible electronically, with key focuses on civil engineering and water project construction. This tender offers significant growth opportunities for firms in the construction and engineering sectors, particularly those with expertise in water projects and reservoir safety improvements. Businesses capable of providing architectural, engineering, and construction-related services, especially those experienced in dam construction and the use of HDPE materials, stand a good chance to compete effectively in this tender. The requirement for specialised installation using qualified divers suggests that firms with niche expertise in underwater construction could also consider bidding. Overall, firms looking to expand their portfolio in civil engineering and safety mechanisms in reservoir management will find this procurement particularly appealing. ## Notice Reservoirs Act 1975: Llyn Mair Reservoir, County of Gwynedd, Eryri National ParkReservoir Safety Improvement Works (MIOS)Tender Expression of InterestStillwater Associates has been employed by Eryri National Park to oversee the implementation of reservoir safety improvement works on Llyn Mair Reservoir. The site is located close to the village of Maentwrog, NGR SH 653 412.The proposed works are the construction of a new siphon pipe to allow the reservoir level to be drawn down in case of emergencies. This is to be achieved by repurposing one of the four existing spillways (Spillway 'C') to contain the new HDPE siphon and then subsequently backfilling with mass concrete or aggregate depending on the location. The upstream leg of the siphon is to be installed using qualified divers with some partial demolition work undertaken to the chamber. Additionally, Spillway 'D' is to be abandoned in situ by forming a wall across the existing channel.The works are required to address statutory recommendations made in the interests of reservoir safety. Eryri National Park has committed to having the works completed by 31st July 2026 and it is imperative that the successful contractor delivers the works accordingly.NOTE: To register your interest in this notice and obtain any additional information please visit the Sell2Wales Web Site at https://www.sell2wales.gov.wales/Search/Search_Switch.aspx?ID=161799.The buyer has indicated that it will accept electronic responses to this notice via the Postbox facility. A user guide is available at https://www.sell2wales.gov.wales/sitehelp/help_guides.aspx.Suppliers are advised to allow adequate time for uploading documents and to dispatch the electronic response well in advance of the closing time to avoid any last minute problems. see tender documents(WA Ref:161799) ## Key Details | Field | Value | | --- | --- | | Publication source | Sell2Wales | | Latest notice | https://www.sell2wales.gov.wales/search/search_switch.aspx?ID=161799 | | Notice type | S2W Notice - Website Invitation to Tender Notice | | Procurement type | Standard | | Procurement category | Works | | Procurement method | Limited | | Procurement method details | Not specified | | Tender suitability | Not specified | | Awardee scale | Not specified | | All stages | Tender | ## Dates | Field | Value | | --- | --- | | Publication date | 20 Feb 2026 | | Submission deadline | 9 Mar 2026 | | Future notice date | Not specified | | Award date | Not specified | | Contract period | Not specified | | Recurrence | Not specified | ## Values | Field | Value | | --- | --- | | Tender value | Not specified | | Lots value | Not specified | | Awards value | Not specified | | Contracts value | Not specified | ## Status | Field | Value | | --- | --- | | Tender status | Not specified | | Lots status | Not specified | | Awards status | Not specified | | Contracts status | Not specified | ## Buyer | Field | Value | | --- | --- | | Main buyer | AWDURDOD PARC CENEDLAETHOL ERYRI | | Locality | GWYNEDD | | Post town | Llandudno | | Postcode | LL48 6LF | | Country | Wales | | ITL 1 | TLL Wales | | ITL 2 | TLL3 North Wales | | ITL 3 | TLL32 Gwynedd | | Local authority | Gwynedd | | Electoral ward | Penrhyndeudraeth | | Westminster constituency | Dwyfor Meirionnydd | | Delivery location | Not specified | ## CPV Codes ### Divisions - 45 - Construction work - 71 - Architectural, construction, engineering and inspection services ### Codes - 45000000 - Construction work - 45200000 - Works for complete or part construction and civil engineering work - 45240000 - Construction work for water projects - 45247200 - Construction work for dams and similar fixed structures - 45247210 - Dam construction work - 45247270 - Reservoir construction works - 71000000 - Architectural, construction, engineering and inspection services - 71300000 - Engineering services - 71500000 - Construction-related services ## Release History - 20 Feb 2026 at 12:18 - Tender - S2W Notice - Website Invitation to Tender Notice - https://www.sell2wales.gov.wales/search/search_switch.aspx?ID=161799 ## Notice URLs - http://www.eryri.llyw.cymru - https://www.sell2wales.gov.wales - https://www.sell2wales.gov.wales/Search/Search_Switch.aspx?ID=161799.The - https://www.sell2wales.gov.wales/sitehelp/help_guides.aspx.Suppliers ## Provenance This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-kuma6s-161799. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-kuma6s-161799.json.