Working with Nature Project database

General information

Name of navigation or waterborne transport infrastructure project The restoration of Salhouse Spit
CountryUnited Kingdom
Project location (nearest town or city)Salhouse, Norwich, Norfolk
Key project objectivesErosion over the last 60 years caused the spit of land between Salhouse Broad and the river Bure to become significantly narrow threatening the integrity of the river bank and its riverside mooring. Now four geotextile bags of a total length of 170 metres retain 10,000 m3 of dredged sediment, forming 7,000m² of reedbed that protects the spit. The final outcome is improved navigation and a healthy reedbed, which is essential to wildlife however also form effective erosion protection
Contact PersonWilliam Coulet
Contact E-mailwilliam.coulet@broads-authority.gov.uk
Contact Phone01603 756038
PositionPrisma Project Manager
OrganisationBroads Authority

Project data

Characteristics of environment
Inland waterway
Rural
Temperate
Protected areas
Key project dates
Project is not in the planning phase. Date project planning started00-10-2011
Project has consents/approvals. Date approval was obtained
15-8-2012
Project construction started. Date construction started8-10-2012
Project not yet completed
Type of project
New construction or development
Maintenance program or initiative
Inland
Waterway
Aquatic relocation/disposal of dredged material
Beneficial use of dredged material
OtherMaintenance dredging of inland waterways and constructing a breakwater and reedbed with dredged sediment.
Brief description
The Broads Authority is restoring a lost reed bed and eroded strip of land at Salhouse Broad, Norfolk. (A Broad is a shallow manmade lake, conventionally dug for peat) Erosion over the last 60 years has caused the land between Salhouse Broad and the River Bure to become significantly narrow –down to 2 metres in places-- threatening the integrity of the river bank and its riverside mooring. Now 7,000m ² of reed bed is being constructed using dredged sediment retained by four giant geotextile bags. The geotubes© are fixed to locally sourced alder poles; cut from river banks near Salhouse Broad. The geotubes are being filled with 3000m ³ of sediment dredged from the River Bure to provide a 170m retaining bank. The geotubes, which are 8.5 metres wide and have a circumference of 18.6 m are big enough to drive a car through! Once filled, they will sink below the waterline and the void behind the bags will be filled in with 8000m³ of dredged sediment to restore the reed bed as it was in 1946. Dredging of the river Bure is required for navigational purposes, shoals have accumulated on the inside of bends and other slow flowing areas. Dredging to a depth of 2.00 metres below mean low water is required, allowing pleasure cruisers and sailing vessels to navigate the river. Sediment from the river Bure is being carried to Salhouse by barge where it is unloaded into a pump by an excavator. The pump, conventionally used for concrete, fills the bags via a pipeline. The use of a concrete pump is required because the sediment pumped is undiluted, in-situ sediment. Geotubes have been filled with sediment before, however not with in-situ (solid) sediment with a concrete pump under water! The surface of the geotextile bags will be planted with reed seed and rhizomes sourced from vegetation scrapes, carried out as part of reed bed management on an adjacent site this winter to help restore it as a natural reed bed.
Indicative size
Less than 0.5 million US$


Working with Nature philosophy

Were steps taken to understand the environment before any work was started on the development of the design of the project?
Yes
A detailed environmental assessment was carried out prior to the works focussing on the specific works area. The Broads are manmade and require specific management to ensure high quality habitats. The aim is to enhance biodiversity by re-creating reedbed, a habitat type that has diminished locally as well as nationally.
Were stakeholders or potential partners involved from the very beginning in the initial process of identifying potential options or solutions and agreeing on a preferred option (i.e. instead of being consulted on already defined options)?
Yes
Stakeholders; landowner, local site managers, the Environment Agency and Natural England as well as the navigation committee were involved from the start of the project. This was achieved by liaising with them during individual meetings. The project was also flexible enough to make minor changes where required during the whole process as it is highly innovative. This is done on several occasions.
Was a solution identified which provided a clear ‘win-win’?
Yes
The project focussed on reusing dredged sediment in a beneficial way. Silty clay was used to form a new reedbed habitat. Resources were found locally like alder poles and reed rhizomes. The alder poles were coppiced as part of the management of the local woodlands, prolonging the trees life and allowing light into the woodland. Reed rhizomes were scraped from a nearby reedbed, improving conditions for pionering species and providing adult and fully established 'mats' of vegetation
Was the project designed to work with and make use of natural processes (e.g. ‘letting nature do the work’)?
Yes
Did the project include benefits for nature or other environmental enhancements beyond what was legally required?
Yes
Yes, as described above; much material will be sourced locally reedbed will be established with significant marginal zones biodiversity will be enhanced with reedbed (nationally declining)
Did the project follow, in order, the steps described in the Working with Nature Position Paper?
Yes
The project followed the steps described, of particular difficulty was to keep 'all' stakeholders pleased. When one works in a dynamic environment like the broads with many different stakeholders somethimes it takes significant efford to please everyone.
Reasons/motivation for taking this approach
The Broads Authority is part of the National Park family and we act as the stewards of Broads. Besides this duty we also require to maintain navigation. By combining the two aspects we can carry out our work more effectively. Win-win situations are essential for operational as well as economic reasons. We aim at the same time to improve the natural environment.
Cost implications
Costs were not lower than the conventional approach to this type of project (i.e. no cost savings were made)
No additional funds were provided from third parties
No extra costs compared to conventional approachSourcing local materials is somethimes not competative in relation to 'on the shelf' products, however because of the win-win situations and the reduction of transport no extra cost were incurred.
Costs were not marginally or significantly higher than a conventional approach to this type of project
Did existing legislation help or hinder your application of the Working with Nature philosophy?
The approach adopted did not help to meet legal obligations
What was done did not exceed legal requirements
No problems were experienced with existing legislation
The approach was not taken despite legal requirements
Legal requirements prevented (some of) the Working with Nature philosophy being appliedSediment is still regard as a waste in legislation, 'building' with sediment is therefore particulary difficult. Because we used sediment within the same waterbody, no hinder was incurred.
Further information
Please contact William Coulet for further information, video's, photo's reports and other information is available.