50500 A group of 3 fishponds and 2 small tanks at North Kelsey Grange, probably the site of an early 13th century grange of the Gilbertine Priory of North Ormsby, lie on the floor of a shallow valley draining west to the river Ancholme. The earthworks of the fishponds are sliced through by the modern creek drain and several field boundaries have been removed, but it is their unusual and complex form of water management rather than this disturbance that makes them difficult to understand. The system is fed by an old stream cut, itself artificial, and which is partly shown as the stream course in a map of 1776. At the west end is a trapezoidal pond with a symmetrical low central island on which a rectangular hollow with an outlet to the north may have been a fish-breeding or sorting tank and slight scarps and a mound at its west end perhaps the remains of a building. Water was retained by banks up to 1.5m high forming an l-shaped dam on the north and west and fading out south against the slope with an outlet in the north-west and an inlet in the south-east from the feeder stream. Against the south-west side of this pond is a further rectangular embanked tank which has an inlet to the south-west and an outlet at the north-west, narrowed for a sluice. An embanked ditch appears designed to drain water from a low-lying area south of the hedgeline and may be a late addition to the complex, and irrelevant to its function. Further east a rectangular pond is bounded on the west and north by broad banks 0.5m to 1.5m high acting as dams and on the south by the feeder stream. Water could be let from it along a shallow channel to the foot of the banks and might have stood against them in a shallow shelving sheet. A second similar pond lies to the east, again with embanking along its north and west sides. A channel along the north side of the north bank may have provided an avoidance channel for the system. {1} The fishpond complex and the grange site were scheduled 16 April 1999. The fishpond complex is believed to be associated with a grange of the Gilbertine priory of North Ormsby which was established at North Kelsey by the early 13th century. The grange, established over earlier ridge and furrow, is thought to have lain on the site of the present farm. Rectangular enclosures also overlie earlier ridge and furrow to the north of the grange site. {4}