]> 2026-04-21T12:01:01+00:00 Case study:Aubourn Rock Ramp and Habitat Works 500 en Aubourn Case Study v1 (Final) 080318.pdf Project Case Study Approved Tree hinging over long section and large rock ramp installation to replace existing large weir that was a barrier to fish passage. Environment Agency Great Britain Yes No Yes true Aubourn 2.png Aubourn 4.png Weir Pre-works Tree Works No 53.152080986039,-0.63628317482514 Matt Environment Agency Parr Tree hinging over long section and large rock ramp installation to replace existing large weir that was a barrier to fish passage.,, ,,, 27120 Constructed Rock Ramp. Aubourn 1.png 2016-01-05Z 2457392.5 Complete Aubourn Weir, located in the lower reaches of the Upper River Witham, presented a major barrier to upstream fish and eel passage and the heavily-modified channel in the vicinity, lacked morphological and habitat diversity resulting in poor fish populations. Also affected by high levels of phosphates, the overall Ecological Status of this section of the river is classified as Moderate. The key objectives of the Aubourn project were to enable fish and eel passage at the weir and to undertake additional enhancements to improve the channel diversity. The wider project, from Bassingham Bridge to beyond Aubourn Weir, sought to enhance the heavily-modified channel using existing riverside trees to create in-stream deadwood habitat, improve flow variation and provide valuable refuges for fish and invertebrates. There were two parts to the project: construction of the rock ramp fish pass and associated bed enhancements in the vicinity of Aubourn Weir, and extensive woody habitat creation from Bassingham downstream to beyond Aubourn Weir. *Rock Ramp - Using large rocks and steel sheet piling to maintain the water levels, a series of stepped pools, rising c1m in c20cm increments, were constructed to create the “rock ramp” which now enables fish and eels to negotiate the former obstruction. *Pools – Five pools were excavated in the river bed, three above the new rock ramp and two below it. The excavated material was deposited against the bank immediately upstream of each pool to narrow the channel and speed up the flow - a technique known as “dig-and-dump”. *Woody habitat - Riverside trees, in particular those that had collapsed in to the river or were in imminent danger of doing so, were selectively hinged and/or secured into the channel and along the bank throughout the whole of the 3.25km reach. The large woody material creates flow variation and provides refuges for fish and invertebrates as the river level and speed of flow changes. Aubourn Rock Ramp and Habitat Works aubourn rock ramp and habitat works No 3200 Witham Anglian Upper Witham upper witham Aubourn Rock Ramp and Habitat Works aubourn rock ramp and habitat works 10 - 100 km² 46 Less than 100 m Upper Witham GB105030056760 Fisheries Habitat and biodiversity 126000 100 - 500 k€ GB105030056780 Witham Confluence Cringle Brook to Confluence Brant 2024-02-17T09:48:45Z 2460357.9088542 2024-02-26T13:21:39Z 2460367.0567014 Aubourn Rock Ramp and Habitat Works 500 1 plainlist 5 [[Category:Case study]] [[Project title::!Aubourn Rock Ramp and Habitat Works]] [[Subcatchment title::Upper Witham]] Aubourn Rock Ramp and Habitat Works# QUERYe16252a2df9da4baa4f081e34692f8c5