Investigation of regulated tidal exchange and water level control structures for management of saline lagoons at North Killingholme Haven Pits Site of Special Scientific Interest, North East Lincolnshire

Tender description

North Killingholme Haven Pits SSSI is near Immingham, North East Lincolnshire, on the south bank of the Humber Estuary (central grid reference TA1662919816). The privately owned,16ha, site comprises former clay pits which have developed into saline lagoons. It is within the Humber Estuary Special Protection Area/Ramsar site and is of international importance for non-breeding waterfowl. The site is connected to the Humber Estuary by a manually operated sluice in the flood bank, which allows for the regulated exchange of tidal water. The sluice is over 50 years old and is not fully functioning due to siltation, and health and safety concerns regarding its operation. The aims of the investigation are to survey the existing water level control structures on site, and appraise the options for management of water levels to achieve the site objectives. Outputs include a levels survey, concept designs and estimated costs for each option and associated actions. Site surveys are required. Technical and practical expertise is required. This is difficult terrain due to tidal mudflats and open water. There is also a working railway line. A site-based risk assessment will be required to be submitted to Natural England. Contract to start 1 September 2025, with final report to be submitted by 1 March 2026.