]> 2026-04-12T07:36:18+00:00 Case study:River Darent at Hawley Manor 500 en Approved Re-working of gravels to create riffles Creation of pools Creation of bars Yes Yes No Improvement No Yes Invertebrates: Taxonomic composition,Yes,Yes,No,Yes,No,Improvement Macrophytes,Yes,Yes,Yes,Yes,No,Improvement Invertebrates: Taxonomic composition Macrophytes Yes Channel narrowing Adding sinuosity Environment Agency Great Britain Environment Agency Yes No Yes false Yes Yes No Improvement Yes Substrate conditions,Yes,Yes,Yes,No,No,Improvement Substrate conditions No Hm 5 BF.jpg HM2005 Before.JPG HM2005 During.jpg HM 3d.jpg HMAfter 2005.jpg HM2010 PPA.JPG Darent 5 09 (3).jpg River Darent at Hawley Manor before works Immediately before works During works Excavator carrying out in-channel works Immediately after works The same reach after five years In-channel vegetation after four years No 51.4251248,0.23084300000005 Tom Environment Agency Cook Re-working of gravels to create riffles, Creation of pools, Creation of bars,,,Channel narrowing, Adding sinuosity, ,,, 5950 The restored reach of the River Darent at Hawley Manor after two years 2005-09-25Z 2453638.5 Hawley July 2007c.jpg Complete The River Darent in the Dartford area has been heavily modified over many years,including changes to channel planform, the implementation of land drainage schemes and abstraction,leading to an over widened channel. Prior to restoration this section of river, two miles upstream of Dartford, was very uniform with a shallow gradient and uniform cross section. The natural substrate is dominated by pebbles and gravel but had become overlain by silt. Flow and habitat diversity was limited with negative impacts on fish and macroinvertebrate communities. The aim of the project was to demonstrate that the processes that sustain a healthy chalk stream could be restored and the habitat protected during drought periods. This was to be achieved in a cost-effective way by re-working the in-channel gravels to form a low flow channel. The restoration work contributed to Chalk Rivers Biodiversity Action Plan (BAP) targets and complemented the implementation of the Darent Action Plan (1992). All of the bed modifications were carried out from within the channel, so the banks and trees were left untouched. The channel was re-profiled using a long reach excavator creating a sinuous channel, with pool and riffle sequences, still within the confines of the original channel. The excavator accessed the river where there were suitable gaps between trees and the creation of gravel berms at these points enabled the excavator to exit the river without damaging the banks. A low flow channel was created by moving small amounts of gravel in a meandering path within the confines of the wider channel. Part of the bed was kept at a higher elevation to create a sequence of riffles. In other areas more significant quantities of gravel were redistributed enabling pools to be created. Pools, spaced at approximately 20m intervals, were designed to be self-cleaning. Gravels were placed upstream of each to narrow the flow and increase velocity to induce scour in the pools. The whole of the construction phase was supervised by the designer who was on site throughout the work and provided instructions to the excavator driver. Existing bankside trees with large root systems acted as natural deflectors and provided a variety of marginal habitat. A small amount of planting was carried out, including water crowfoot which was sourced locally from the Darent. River Darent at Hawley Manor river darent at hawley manor No 250 Darent Thames Mid Darent mid darent River Darent at Hawley Manor river darent at hawley manor 100 - 1000 km² 244 200 - 500 m Mid Darent GB106040024222 Habitat and biodiversity Hydromorphology 2114 1 - 10 k€ GB106040024222 Mid Darent 2005-09-24Z 2453637.5 2005-09-24Z 2453637.5 2013-07-03T16:24:08Z 2456477.1834259 2017-06-01T15:17:33Z 2457906.1371875 River Darent at Hawley Manor 500 1 plainlist 5 [[Category:Case study]] [[Project title::!River Darent at Hawley Manor]] [[Subcatchment title::Mid Darent]] River Darent at Hawley Manor# QUERY052a3bf2e2d3d96f7b16e8bb9f893aab