For management purposes the River Rye is divided into two units, Ness and Howe Bridge.
Ness Ness is the upstream area and covers . It covers the River Rye and its tributaries from its source to its confluence with the River Dove near the village of
East Ness. The Ness area is mainly rural with dispersed settlements. It has varied topography, the northern part is dominated by upland moors which are over in height in the
North York Moors National Park. Here the land use is largely managed grassland. Downstream, as the river approaches
Rievaulx and Helmsley the land is around in height and falls to at
East Ness. In the lower part, land use is a mixture of managed grassland and arable farming with pockets of forestry and woodland close to the river. Abstraction from the river is mainly to supply a fish farm at Harome and this water is returned to the river. Wastewater treatment works have been built at Helmsley and Sproxton. The ecology and fisheries are highly sensitive to changers in water flow.
Howe Bridge The Howe Bridge area covers . It covers the River Rye from East Ness to its confluence with the River Derwent just beyond Howe Bridge. In this area the main tributaries are the
River Riccal,
River Dove (with Hodge Beck),
River Seven,
Costa Beck and
Pickering Beck. The market towns of
Pickering and
Kirkbymoorside are the largest settlements. Otherwise the area is rural with a varied topography. To the north is the upland moorland of the North York moors with the valleys of
Bransdale,
Farndale,
Rosedale and Newtondale. Much of the moorland is over in height with the highest point being . To the south the tributaries from the valleys converge and the land becomes flatter. It is mainly lower than . To the south-west the Howe Bridge area covers the undulating landscape of the Howardian Hills. The largest abstractions are for fish farming. Wastewater treatment works are at Pickering, Harome and Kirkbymoorside. ==Geology==