The Somerset Drainage Board Consortium maintains some 786 km of drainage lines, 200 water control structures and 409 km² of area. Water levels within the drainage area are managed to achieve an agreed water level at different times of the year. In order to both understand and develop the impact of the water level management plans it was necessary to undertake hydraulic modelling of the drainage area.
M J Rees carried out topographical surveys and surveyed cross sections at various structure locations throughout the Northmoor and Saltmoor areas including bridges, culverts and sluices. Cross sections were also surveyed across the open channel sections of the rhynes. In total sixty-three cross sections were surveyed. Most sections were surveyed from a boat with a qualified boat handler. A network of GPS control stations was also established across the survey area.