]> 2026-04-14T10:26:05+00:00 Case study:Castle Acre Rehabilitation Project 500 en NAR Spring 2011 - as built project report.pdf River Nar Rehabilitation summary report by Nigel Holmes Approved Creation of pools and riffles Channel narrowing River Restoration Centre Environment Agency Natural England Great Britain Environment Agency Norfolk Rivers Internal Drainage Board Yes Yes Yes false No 52.699976091858,0.69016456604004 Nigel T.H. River Restoration Centre Holmes Creation of pools and riffles,,,Channel narrowing, ,,, 5604 Environment Agency, River Restoration Centre, Natural England, River Nar SSSI at Castle Acre NarCastleAcre.JPG Complete Work was considerable, affecting about 65% of the channel within a stretch of c300m. Work was undertaken to create greater diversity of habitat by modifying both the long and cross-sections (formation of pools and fast ‘run’ habitat); narrow the channel to improve self-cleansing of the bed and thus reduce sand and silt deposition as well as ‘weed’ growth in the future; improve the landscape quality of the area by replacing the unsightly deflectors with ‘living’ features that would do a more effective job than the deflectors were attempting to do. This section of river has more gradient than the other two sites, and this tended to recede on passing downstream. In habitat terms it primarily suffers badly from historic widening, and attempts to narrow it with deflectors have been generally ineffectual due to the inability of marginal plants to encroach and become firmly established – some deflectors have, however, established some habitat diversity. The key to being able to carry out the works as desired was the presence of large patches of sedge (Carex acutiformis) and reed (Phalaris arundinacea). In several places the river was narrowed by over 4m simply by transferring large ‘sods’ of sedges; these imports were placed within the inside the existing bank, and will now form the new bank. In the upstream straight section to the first bend, three pools and upstream deflectors were created. As the bed of the newly created two downstream pools of this sequence (photos 2-5) had flinty-gravel present, this was sprinkled on the bed of the narrowed channel upstream to accentuate the improved speed of flow into the pools, and improve the habitat variability within the reach. Material dug from pools to form the upstream shoulders that narrowed the channel were blinded by sedge/reed from the adjacent field. These features were enlarged by further sedge/reed sods. Castle Acre Rehabilitation Project castle acre rehabilitation project No 300 North West Norfolk Anglian Nar to confl with Blackborough Drain nar to confl with blackborough drain Castle Acre castle acre 100 - 1000 km² 95 Less than 100 m Nar to confl with Blackborough Drain GB105033047791 Habitat and biodiversity GB105033047791 Nar to confl with Blackborough Drain 2011-03-31Z 2455651.5 2011-03-01Z 2455621.5 2013-04-09T11:07:06Z 2456391.9632639 2018-11-01T12:53:43Z 2458424.0373032 Castle Acre Rehabilitation Project 500 1 plainlist 5 [[Category:Case study]] [[Project title::!Castle Acre Rehabilitation Project]] [[Subcatchment title::Nar to confl with Blackborough Drain]] Castle Acre Rehabilitation Project# QUERY9de6a88d1a449b34af01ee7a25827085 500 1 list 3 [[Category:Case study]] [[Parent project::Case study:Castle Acre Rehabilitation Project]] Castle Acre Rehabilitation Project# QUERY5136db6ab03d9355808b706dbec1b831