£100,000 improvements to Hampshire stream set to get underway

Bosses at National Trust and the Environment Agency are behind the £100,000 work to improve the flow and quality of water on the Oakley Stream at Mottisfont - an important carrier of the River Test.

Hundreds of tons of gravel will be laid on the river bed to improve its flow and habitats of the stream which is best known for its fly-fishing. It was here that the world-renowned angler and leading author on fly-fishing Frederic Halford fished early last century. A thatched fishing hut that he built has been preserved by the National Trust and it stands along the banks of the river.

Mottisfont Estate's general manager Paul Cook said the Oakley Stream is currently classified as being in "unfavourable ecological condition" and does not meet current European water quality standards.

Mr Cook revealed that the restoration work will start on Monday (October 12) and 1,600 tones of gravel will be brought into the site off Oakley Lane by lorries over a five-day period.

"The gravel movement is now confirmed to start on Monday and we anticipate it will take five days to complete. To achieve this there will need to be 16 lorry loads arriving each day - one approximately every 30mins during the working day.

The trucks will come in through Mottisfont village, and then go back out through Dunbridge once the delivery has been made. This spreads the disruption and also avoids the trucks meeting in the narrow parts of Mottisfont and Dunbridge, which could cause more disruption," said Mr Cook, whose team have circulated letters to all those living along the route of the gravel deliveries.

He added: " We will be starting a project to restore this section of Special of Special Scientific Interest river to a healthy, productive chalk stream habitat – in a manner that will enhance the site both now and for future generations.

"When in good condition chalk streams and their surroundings provide wonderful habitat for a rich variety of fish, insect, animal, bird and plant life – including endangered species such as water voles and the southern damselfly. On sections of the stretch in question historical dredging has made the river channel 'over-deep.' Additionally poor flow rates have led to the significant deposition of silt on the river bed. These issues inhibit the successful spawning of key fish species such as brown trout and salmon, prevent the growth of typical chalk stream plants, and limit the diversity of invertebrate species that can inhabit the river."

Mr Cook said researchers at Southampton University had identified "a number of impoundments that are reducing the flow rate of the river" and the enhancement work will include the removal of a rock weir.

He also added that gravels that were previously put into the river, will be spread over the stream's bed.

"These steps will significantly improve the flow rates of the river.

"This will be followed by raising the river bed of the over deep sections through the addition of large amounts of gravel. Raising the bed in this way will further improve flow rates and provide habitat for, typical chalk stream invertebrates and plants, and gravels," said Mr Cook, adding that the initial work will be done by contractors. National Trust volunteers and Sparsholt College students will be involved in the finishing stages of the project which is part of the Environment Agency's River Test Restoration Strategy.