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. Light or indepth? Light NUTS Code Ticino RBD code CH50 Transboundary 0 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 54 Mean runoff unit 0 - 150 mm Average runoff coefficient 0,25 Type Case Study Info 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 Other Initiation of the measure Chêne Bougerie town Financing Architects Private property owners Determination of design details of the measure Solfor SA Architects Private property owners Implementation Jacquet SA Engineers 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 Legal obligations secondary factor Financing Financing type Comments Local funds Private funds Barrier Barrier type Barrier role Comments Expected maintenance needs secondary barrier Private owners are responsible for maintaining vegetation on their plots 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 National funds View Private funds Private owners finance vegetation maintenance View 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 Full Context Pathway(aka Context) Default view Area(aka Level or Site) ALL