Retention pond in Chêne Bougerie, Switzerland

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:

Data provider:

Anais Hanus, ACTeon

Source(s):

Chemin du Vieux-clos: étang de rétention et biotope

NWRM(s) implemented in the case study:

Retention Ponds

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:

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:

Performance

Performance impact estimation method:

Unknown

Performance impact estimation information:

null

Biophysical impacts

Increased water storage:

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

Lessons, risks, implications...

Key lessons:

Example of how to retain water in urban areas

Financing mechanism:

Success factor(s):

Type	Role	Comments
Legal obligations	secondary factor	Legal obligations can lead stakeholders to implemnt measures to retain water in urban areas
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

Financing:

Type	Comments
Local funds
Private funds

Barrier:

Type	Role	Comments
Expected maintenance needs	secondary barrier	Private owners are responsible for maintaining vegetation on their plots

Driver:

Type	Role	Comments
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
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)

Financing share:

Share type	Share	Comments
National funds
Private funds		Private owners finance vegetation maintenance

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:

Information on Ecosystem improved biodiversity:

The pond provide habitat for fauna and flora, including aquatic flora

Ecosystem provisioning services:

Ecosystem water supply:

Ecosystem impact climate regulation:

No information available

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:

Policy pressure:

Policy requirement directive:

Policy 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 area:

Policy target:

Target purpose
Increase Water Storage
Improved Biodiversity
Oher Societal Benefits

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:

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:

Contractural arrangements:

Design contractual arrangement:

Design consultation activity:

Design land use change:

Land use change type
Water bodies

Design authority:

Authority type	Role	Name	Comments
Other	Initiation of the measure	Chêne Bougerie town
Private property owners	Determination of design details of the measure	Solfor SA	Architects
Private property owners	Implementation	Jacquet SA	Engineers
	Financing		Architects

Last updated: 12 Jan 2015 | Top

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Retention pond in Chêne Bougerie, Switzerland

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