Revitalisation of riverbanks and connection of hydraulic annexes alongside the Scarpe river in France
Summary
Summary
The Scarpe in Arras (long canalised) was renatured (2009–2012) to balance navigation, recreation and ecology. Actions included removal of sheet piling, gentle bank reprofiling, mixed bio-engineering (hemp bundles, vegetated geonets, gabion mattresses where needed), riparian restoration (invasives removal, seeding, pollarded white willows), controlled access, and creation of a lagoon.
The project treated 1,760 m of banks and built two reedbeds (≈1,000 m² and 1,450 m²). In the same programme, a 1.4 ha pike spawning area at Fampoux was re-opened and reconnected to the Scarpe. Governance shifted in 2012 via a VNF→Arras Urban Community (CUA) convention; FDAAPPMA 62 manages the spawning sites. Baseline surveys were done in 2010 with a five-year follow-up planned.
Total cost €1,321,310 (studies €132,277; works €1,189,032), co-funded by Artois-Picardie Water Agency 51%, ERDF 48%, CUA 1%.
The reach remains actively managed. In 2022 the environmental authority (MRAe) reviewed a 10-year dredging plan (~180,000 m³) to secure a 1.65 m navigation draft, notably around the Saint-Laurent-Blangy water-sports base, and requested stronger WFD compliance, better fish/European eel assessment, and a catchment-scale response to upstream sediment inputs. Together, the restoration and ongoing management aim to diversify habitats while keeping the canal’s socio-economic uses.
Photo gallery
Overview
Year of issue
2025
Project
NWRM
Implementation status
Completed
Contact
Elia Desmot, OIEau
Location of the project
The Upper Scarpe Canal, which flows for 23 km, connects Arras to Corbehem via navigation through nine locks.
Country
France
NUTS2 Code
Nord - Pas-de-Calais
Sponge measures implemented in the case study
Stream bed re-naturalisation
Natural bank stabilisation
Reconnection of oxbow lakes and similar features
Objectives
Improve biological & chemical quality; recreate reproduction habitats. Targets: maintain burdock, pike & eel populations; establish ≥1 amphibian species; double the number of bird and insect species vs 2010 baseline.
Involved partners
| Authority type | Authority name | Authority role | Comments | Authority responsibility |
|---|---|---|---|---|
| Local water authority | Communauté Urbaine d'Arras (CUA) | Initiation of the measure | Project owner | Responsible |
| Regional / sub-national water authority | Agence de l'eau Artois-Picardie | Financing | Financing 51 % of the project | Supporting |
| Other | Fédération départementale des associations agréées pour la pêche et la protection des milieux aquatiques du Pas-de-Calais | Determination of design details of the measure | The management of the two recreated spawning areas is carried out by the Departmental Federation of Pas-de-Calais for fishing and aquatic environment protection (FDPPMA 62). | Supporting |
Site Information
Climate Zone
Cool temperate moist
Precipitation
618.00 mm
Temperature (°C)
10.80 °C
Elevation range
75 m
Vegetation class
Reedbeds (Phragmites) from two constructed roselières (≈1,000 m² & 1,450 m²), helophyte fringes, and riparian white willow (Salix alba) pollarded; hydrophilous bank flora.
WFD Ecological status
Poor
WFD Chemical status
Failing to achieve good
Water quality status
Heavily modified canal reach: past sheet-piling, limited habitats; sediment infill from upstream; runoff of agricultural inputs in marshes; invasive plants; leisure & geese pressure; WFD compliance issues flagged for dredging.
Design and Implementation
Project scale
Micro
Project scale specifications
Works on ~1.76 km of banks within a specific urban reach, plus a single oxbow-type lagoon and one 1.4 ha pike spawning area—localised hydromorphology and habitat measures.
Size
1760.00
Size unit
m
Principles
Multi-functionality: reconcile navigation/recreation with ecological restoration. Strategies: remove sheet-piling; gentle re-grading; bio-engineering (gabion mattresses + vegetated geonets; helophyte bundles); riparian restoration; controlled access; create alluvial annex/lagoon. Capacities (not storm-event-based): 1,760 m banks treated; reedbeds ~2,450 m² total; pike spawning area ~1.4 ha; dredging plan targets 1.65 m draft (separate O&M).
Factor constraints
Low-slope canalised river with historic sheet-piling; access constraints required working from water; strong leisure use and geese grazing; need to maintain navigation; presence of valuable but fragmented wetland habitats; prior dragage needed to mobilise equipment.
Constraints
River banks protected by grey infrastructure
Favourable preconditions
Population favourable to the change
Financing
Total cost
1321310.00 €
Total cost information
Preliminary studies : € 132,277
Works and developments : € 1,189,032
Works and developments : € 1,189,032
Compensations
No
Policy and Governance
Policy description
Protection of riverbanks. Current dredging PGPOD (10 yrs, ~180,000 m³) reviewed by the environmental authority, which requested stronger WFD alignment and fish/eel assessments and urged basin-scale sediment management.
Land ownership
Public river domain (State/VNF). Day-to-day management of the canalised reach was delegated to the Arras Urban Community (CUA) from 1 Jan 2012. Spawning sites managed with the Pas-de-Calais anglers’ federation.
Policy targets
Improved Biodiversity
Peak-flow reduction
Pollutants Removal
Oher Societal Benefits
Target remarks
Improve biological and chemical water quality in the Scarpe river
Recreate breeding habitats for species
Recreate breeding habitats for species
Requirement directive
| Requirement directive |
|---|
| WFD-achievement of good ecological status |
| WFD-restoring a HMWB |
Part of a wider plan
No
Public consultation
No
Has contractual arrangements
No
Impacts and Monitoring
Monitoring System
Monitoring parameters
Checking of vegetation's health
Impact Assessment Methodology
Performance impact assessment method
Unknown
Biophysical impacts: Hydrology
Information on retained water
Improved lateral connectivity via annex lagoon; diversification of marginal habitats; replacement of hard banks with low-slope vegetated margins; expected gains in habitat complexity. No quantified water-retention volume reported.
Biophysical impacts: Biodiversity
Improved biodiversity
Yes
Information on improved biodiversity
New fish species and vegetation development observed.
Biophysical impacts: Water & Soil Quality
Water quality overall improvements
N/A info
Information on water quality overall
The riparian area associated to the river has been improved and therefore the pollution is better managed
Soil quality overall improvements
N/A info
Information on soil quality overall improvements
Biodiversity enhanced
Biophysical impacts: Others
Ecosystem impact climate regulation
No specific impact
Information on ecosystem impact climate regulation
Not mentioned
Lessons Learned
Key lessons
The revitalisation of the Scarpe River led to an improvement and a diversification of its related aquatic and terrestrial habitats. Therefore, this project participated in enhancing the ecological status of the river, expected to be good by 2021. The perception of the population was very positive thanks to the amenity space provided. However, the fact that the work took place from the river made its realisation difficult and a population of gooses is now disturbing the growth of the planted vegetation.
The various developments carried out allow for the reconciliation of both the ecological value of the site and the use of the waterway, namely commercial navigation, recreational boating, and associated leisure activities. As a result, the site's landscape value is enhanced, with a positive impact on tourism or recreational boating, as well as on leisure activities (such as walks...).
The various developments carried out allow for the reconciliation of both the ecological value of the site and the use of the waterway, namely commercial navigation, recreational boating, and associated leisure activities. As a result, the site's landscape value is enhanced, with a positive impact on tourism or recreational boating, as well as on leisure activities (such as walks...).
Drivers
| Driver type |
|---|
| Organisation committed to it |
Success factors
| Success factor type |
|---|
| Attitude of relevant stakeholders |
Transferability
Applicable to canalised urban rivers. Key cautions: geotechnical stability of regraded banks; invasive-species control; balancing navigation with habitat goals; address catchment sediment sources or dredging benefits won’t persist; document WFD non-deterioration.