Roydon Mill Inland Marina, Harlow, Essex

A new marina has been developed within an existing lake adjacent to the River Stort in Roydon, Essex. The project included the construction of a 30m long pond lock, sheet piled walls, elevated building platform and piled servicing area.

The Roydon Mill project is the only privately funded lock to be constructed in the past ten years. The marina has a capacity to berth up to 315 vessels and is the largest inland marina in South East England.

A ground investigation was carried out in order to determine the underlying soil conditions. RSA Geotechnics were commissioned by Land and Water Services to form four conventional light-cable percussion boreholes to depths of between 12 and 15m. The investigation revealed made ground to a maximum depth of 2m underlain by Alluvium to 7m overlying River Terrace Deposits to 9m and Upper Chalk at depth. Thin-walled undisturbed piston samples were recovered in the soft alluvial materials in order to gain the shear strength of the near-surface materials. In-situ permeability tests were carried out in the boreholes at 10m and 15m depth to gain some information on the permeability of the chalk.

The pond lock was designed using a traditional form of structure developed centuries ago but was achieved using modern construction materials and techniques. The development was completed in only six months. High flood levels meant that the new clubhouse and chandlery had to be elevated by 1.5m above the existing ground level.