General
National Id
Switzerland_03
Site name
Chêne Bougeries
Summary
This case study is located in Switzerland, in the city of Chênes Bourgerie. It presents one of the natural water retention measures that can be implemented in urban areas to reduce runoff and flood risks. A retention pond is implemented on a plot to retain about 450m3 of water, which contribute to retain water at the watershed scale (279m3 for 3,1ha). The pond also provides a "natural" area which can be used as recreative area for neighboring private owners and contributes to reduce mosquitos density.
NUTS Code
Ticino
RBD code
CH50
Transboundary
0
Data provider
Anais Hanus, ACTeon
NWRM(s) implemented in the case study
Longitude
6.187778
Latitude
46.197778
Site information
Climate zone
cool temperate moist
Mean rainfall
942
Mean rainfall unit
mm/year
Average temperature
10,1000003814697
Mean runoff
54
Mean runoff unit
0 - 150 mm
Average runoff coefficient
0,25
Type
Case Study Info
Light or indepth?
Light
Average slope range
1-2%
Monitoring maintenance
Monitoring impacts effects
0
Performance
Performance impact estimation method
Unknown
Performance impact estimation information
null
Design & implementations
Application scale
Plot
Installation date
1995
Lifespan
100
Performance timescale
< 1 year
Area (ha)
3,09999990463257
Area subject to Land use change or Management/Practice change (ha)
0,0299999993294477
Size
300
Size unit
m2
Design capacity description
The pond itself can retain 460m3; the estimated volume of retained water for the whole watershed is 279m3
Max water retention capacity
0,469999998807907
Max water retention capacity unit
m3/sec
Runoff treatment capacity unit
mm/month
Constraints
No particular constraint
Favourable preconditions
No particular favrable conditions
Public consultation
0
Contractural arrangements
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 | |
|---|---|
|
Water bodies
|
Design authority
| Authority type | Role | Responsibility | Name | Comments | |
|---|---|---|---|---|---|
Lessons, risks, implications...
Key lessons
Example of how to retain water in urban areas
Financing mechanism
0
Success factor(s)
| Success factor type | Success factor role | Comments | |
|---|---|---|---|
|
Attitude of relevant stakeholders
|
main factor
|
Since private owners are responsible for maintaining vegetation on their plots, the measure efficiency partly depends on their attitude |
|
|
Legal obligations
|
secondary factor
|
Legal obligations can lead stakeholders to implemnt measures to retain water in urban areas |
Financing
| Financing type | Comments | |
|---|---|---|
|
Local funds
|
||
|
Private funds
|
Driver
| Driver type | Driver role | Comments | |
|---|---|---|---|
|
Other
|
main driver
|
The main driver which led to consider the measure was the new status of the land which became available to be constructed; water management became a major issue.
|
|
|
Other
|
main driver
|
The measure was estimated cheaper than another project (re-build existing infrastructures)
|
|
|
Legal obligations
|
main driver
|
The federal law on water protection requests rain water infiltration in urban areas through retention measures
|
|
|
Organisation committed to it
|
secondary driver
|
Geneva Canton elaboraed recommandations regarding water retention in urban areas
|
Financing share
| Financing share type | Share | Comments | |
|---|---|---|---|
Policy, general governance and design targets
Policy description
The main targeted problem is the management of rainwater on a plot that is going to be constructed
Part of wider plan
0
Policy target
| Target purpose | |
|---|---|
|
Increase Water Storage
|
|
|
Improved Biodiversity
|
|
|
Oher Societal Benefits
|
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 | |
|---|---|---|---|---|
|
National
|
Water
|
federal law on water protection, 24 january 1991
|
||
|
Local
|
Water
|
Cantonal law on water (L 2 05)
|
Policy requirement directive
| Requirement directive | Specification |
|---|
Socio-economic
Direct benefits information
The pond reduce runoff in the area and the damages it can generate
Ancillary benefits information
The pond provides a "natural" area which can be used as recreative area for neighboring private owners. It also contributed to reduce mosquitos density.
Costs operation maintenance
49000
Costs total
49000
Ecosystem improved biodiversity
1
Information on Ecosystem improved biodiversity
The pond provide habitat for fauna and flora, including aquatic flora
Ecosystem provisioning services
0
Ecosystem water supply
0
Ecosystem impact climate regulation
No information available
Biophysical impacts
Increased water storage
90
Increased water storage unit
m3/ha
Information on increased water storage
279m3 can be retained at the watershed scale (3,1ha)
Water quality overall improvements
Not relevant for this application
Soil quality overall soil improvements
Not relevant for this application
