[9] Bilsdale is narrow and densely wooded at the head of the valley, but further down becomes wider and the water meanders before it joins the Rye.

[10] The river has suffered with invasive species such as Himalayan balsam and Japanese Knotweed which have been the subject of various programmes to eradicate them.

[15][16] The river flows across the south western edge of the North York Moors and as such has limestone, gritstone, mudstone and siltstone as its bedrock.

[17] The sides of Bilsdale where the Seph meanders, are lined with ancient Oak trees and the North York Moors National Park Authority were granted Heritage Lottery Funding in 2017 to protect the land and study the wildlife along the upper reaches of the River Rye.

This will include the Seph and will look at some of the native species which make use of the watercourse such as the alcathoe bat and the white-clawed crayfish.