General
National Id
Belgium_02
Site name
Lippenbroek, Zeeschelde
Light or indepth?
Light
RBD code
BEEscaut_Schelde_BR
Transboundary
0
Data provider
Elia Desmot, OIEau
Source(s)
NWRM(s) implemented in the case study
Longitude
4.171
Latitude
51.085
Site information
Climate zone
cool temperate moist
Type
Actual Test Site
Monitoring maintenance
Monitoring impacts effects
1
Monitoring parameters
Accretion or erosion on site; tidal levels and velocities; creek morphology; suspended solids; soil nutrients; water quality (incl. metals); light climate; bioturbation; invertebrates; vegetation; birds; fish;
Performance
Performance impact estimation method
Unknown
Design & implementations
Application scale
River
Installation date
2006
Lifespan
100
Age
8
Performance timescale
< 1 year
Area (ha)
10
Design capacity description
40000m3
Constraints
Scheme implementation was slowed by financial aspects and public opinion - consequently the project took a long time to materialise.
Favourable preconditions
The scheme was made possible by a desire for integrated water management.
Public consultation
0
Design contractual arrangement
| Arrangement type | Responsibility | Role | Comments | Name |
|---|
Design consultation activity
| Activity stage | Key issues | Name | Comments |
|---|
Design land use change
| Land use change type |
|---|
Design authority
| Authority type | Role | Responsibility | Name | Comments |
|---|---|---|---|---|
Lessons, risks, implications...
Key lessons
The Controlled Reduced Tide (CRT) technique employed at Lippenbroek has potential applicability for habitat creation along other heavily developed estuaries. It furthermore represents a technique which can significantly reduce the tidal prism of a site, without compromising the development of a range of intertidal habitats, thus minimising potential negative effects on small estuary systems. The technique also enables the establishment of intertidal habitats at lower elevations in the tidal frame than those of intertidal systems fronting a defence, and would thus be of potential use in areas where land levels behind a defence are relatively low compared to fronting levels. However, longer flood duration and low-turbidity stages may lead to higher accretion rates than in adjacent natural systems(ABPmer, 2008).
Success factor(s)
| Success factor type | Success factor role | Comments |
|---|---|---|
|
Attitude of relevant stakeholders
|
secondary factor
|
Financing
| Financing type | Comments |
|---|---|
|
National funds
|
Driver
| Driver type | Driver role | Comments |
|---|---|---|
|
Past flooding events
|
main driver
|
|
|
Other
|
Loss of goods and services (loss of intertidal habitats)
|
|
|
Other
|
loss of ecosystem functions (and thus loss of safety)
|
Financing share
| Financing share type | Share | Comments |
|---|
Policy, general governance and design targets
Policy description
Demonstration site, improved flood defence, habitat creation
Part of wider plan
0
Policy target
| Target purpose |
|---|
|
Peak-flow reduction
|
|
Improved Biodiversity
|
Policy pressure
| Pressure directive | Relevant pressure |
|---|
Policy area
| Policy area type | Policy area focus | Name | Comments |
|---|
Policy impact
| Impact directive | Relevant impact |
|---|
Policy wider plan
| Wider plan type | Wider plan focus | Name | Comments |
|---|
Policy requirement directive
| Requirement directive | Specification |
|---|
Socio-economic
Ecosystem improved biodiversity
1
Information on Ecosystem improved biodiversity
With regards to birds, despite the high degree of disruption by humans (including site visitors,cyclists and walkers on the dike), a clear change in the numbers and species of birds using the site could be observed when compared to baseline conditions. Of the 4,089 individuals observed during the first year of monitoring, 30% were benthic foragers (19 species), 54% wetland-generalists (11 species), 8% terrestrial generalists (18 species) and 8% woodland birds (13 species). Occasionally night herons Nycticorax nycticorax and spoonbills Platalea leucorodia were observed feeding (Maris et al., 2008). In order for a CRT to fulfil a role for fish, safe passage of the cluvers/sluices is required.
Ecosystem provisioning services
1
Information on Ecosystem provisioning services
Flood protection
Ecosystem impact climate regulation
No specific impact
Information on Ecosystem impact climate regulation
Not mentioned
Biophysical impacts
Information on retained water
average water exchange volume: neap tide: ~4,000m3 (none on the lower neap tides)
Information on increased water storage
spring tide : ~40,000m3
Water quality overall improvements
N/A info
Information on Water quality overall improvements
With respect to water quality, the oxygen enriching impact, which is mostly due to the high inlet sluices acting as aerators, has been described as †˜striking†™. At the sluices, an immediate increase of up to 60% has been observed and a further 20% enrichment has been attributed to surface oxygenation.
Soil quality overall soil improvements
N/A info
Information on Soil quality overall soil improvements
Biodiversity enhanced
Information on Soil quality, overall soil physical properties
Sedimentation was strongly related to flooding frequency; i.e. the highest sedimentation rate was observed at sites inundated around 85% of the time. The average sedimentation rate is currently fairly high at approximately 4 cm/year. The lowest sites are accreting fastest, hence the polder is loosing slope. Outside the polder, in natural marshes, an increase in elevation would lead to a decrease in flooding frequency, and a consequent gradual decrease in sedimentation. Conversely in the CRT the flooding frequency is not directly coupled to elevation; the intake volume is stipulated by the sluice configuration.