Feltwell reservoir is a potential strategic water resource for the whole of East Anglia. This paper describes the work undertaken by Binnie Black & Veatch on the technical aspects of the site identification, pre-feasibility and feasibility studies for the construction of a reservoir at Feltwell. The process by which the site was identified is described. The incremental approach to the assessment of the feasibility of developing a reservoir at the site involving a desk study, preliminary ground investigation, pre-feasibility study and feasibility study is outlined. The bulk of the paper discusses the feasibility study undertaken in 1997/98. A feasibility ground investigation was carried out and a digital geological model was developed. This geological model was used to assess the optimum reservoir depth and capacity and to determine the embankment alignment. The problems associated with the site geology are discussed, particularly in relation to the peat covering the site and the sourcing of material for filters and drains. The selection of cut-off options and the dewatering requirements are described. The complex hydraulics of the inlet/ outlet system are also described together with the proposed solution.