The market town of Louth (in Lincolnshire), on the River Lud, has suffered from flooding on many occasions, most recently in 2007. Atkins was commissioned to conduct a feasibility study into the potential for a flood defence scheme. This paper begins once the preferred option of two online flood storage areas had been identified; the brief from this point was to develop their outline design. Atkins worked closely with a contractor to develop a cost estimate for the works and to ensure buildability was considered. The two dams are designed as homogenous earth fill embankments, with heights of circa 6 m, and retaining a combined volume of 213 000 m3 (during a flood event); both storage areas fall under the requirements of the Reservoirs Act 1975. As in many cases, these reservoirs present particular challenges; designed to be empty for the majority of their life, they are required to meet the needs of a variety of stakeholders. The design was further complicated by the risk of unexploded ordnance and burrowing animals. This paper presents the outline design under three sections: the location, embankments and control structures. For each section the paper discusses the alternatives considered, the selection process and the adopted design.