moated sites and watermills show near-continuous occupation throughout the Middle Ages. The Bristol Channel floods of 30 January 1607 (New style), caused by either a storm surge or a tsunami, resulted in the drowning of an estimated 2,000 people, with houses and villages swept away, an estimated of farmland inundated and livestock destroyed. This was one of the worst natural disasters recorded in Britain. Drainage and management Most of the levels has been the subject of artificial drainage schemes, and the area is criss-crossed by drainage channels, known locally as 'reens'. Many of these are now managed by the Caldicot and Wentlooge Levels Internal Drainage Board. In 1531, Henry VIII set up Courts of Sewers to improve drainage, but without any powers to oblige landowners to carry out work. In 1884, the Caldicot and Wentlooge Level Act established a new body, the Monmouthshire Commissioners of Sewers, with responsibility for maintaining sea walls and roads in the Levels. The long title of the Act is "An Act to provide for the commutation of the liability of Landowners in the Levels of the hundreds of Caldicot and Wentlooge in the County of Monmouth to maintain sea walls and other works to provide for the making and maintaining of roads in the said Levels and for other purposes." This was superseded in 1942 by the Caldicot and Wentlooge Levels Drainage Board, now the Internal Drainage Board or IDB. In 2012, the IDB was criticised in a report by the Wales Audit Office for overpaying staff, paying for trips abroad for its members, and acting unlawfully on other occasions. The IDB accepted the report and stated that the organisation's management had changed substantially since the time of the offences. Newport West MP Paul Flynn called for further police investigation into what had happened. The pattern of ditches now found on the Caldicot Level has been complicated by the construction of the Newport Wetlands Reserve. Whereas the raison d'etre of all previous reens and ditches had been to drain the land, the aim of the network of new waterways constructed as part of the reserve has been to keep the land flooded, albeit with fresh water. Ecology The levels support the following rare species: Variable damselfly (Coenagrion pulchellum) Flowering rush (Butomus umbellatus) – an unusual water-edge plant with sprays of pink flowers in May and June Lapwing (Vanellus vanellus) Musk beetle (Aromia moschata) – a