Tampere - City planning, geology and climate change 3 rd International BaltCICA Conference Petri Jokinen, City of Tampere 19 th January 2012
City of Tampere in BaltCICA: City of Tampere is located between two large lakes, Lake Näsijärvi and Lake Pyhäjärvi. The level of Lake Näsijärvi is 17 m higher than Lake Pyhäjärvi. The study area in BaltCICA is the Pyynikin-Epilänharju esker between the lakes. What risks the climate change and possible changes in surface waters and groundwater cause for the esker area? Adaptation options?
Goals Lake Näsijärvi Esker Groundwater level?? Springs Clay Bedrock?? Clay and sand Lake Pyhäjärvi Modeling the esker: 3D geological model (drilling, gravimetric measurements, groundwater wells) Developing concrete climate change adaptation options and measures on the study area
What was done and concluded in Tampere: Field investigations and 3D acquired model completed in 2011 by City of Tampere and GTK (Geological Survey of Finland) Stakeholder involvement: discussions with urban planners, a stakeholder seminar was held in April and a stakeholder workshop in October 2011 According the Tampere regional climate change scenario the main risks has to do with increasing precipitation and extreme weather events On the esker area the special risks are possible soil erosion and artesian groundwater
What are the findings/results: There is no bedrock inside the esker above Lake Näsijärvi surface Artesian aquifer(s) on the southern slope
3rd International BaltCICA Näsijärvi +95,4 m Conference 7500 years ago +99 m Structure of the esker Cross-section from the most narrow part The structure of the esker is not threatened Pyhäjärvi +77,2 m
Artesian groundwater Artesian aquifer(s) under clay layer located by the Lake Pyhäjärvi shore line might be a problem for all constructions Requires further studies Photo Tiina-Liisa Aalto
Risks for the downstream The future flooding risks are located downstream of the water system. Kokemäenjoki Drainage Basin covers 27 100 sq.km Challenges for the regulated water flows Pori Tampere Hämeenlinna Photo Tiina-Liisa Aalto
Risks for the esker Due possible changes in precipitation, evaporation and degree of soil sealing: Changes in the level and the gradient of ground water - risk on the stability of the esker Amount of lake water in the ground water might increase, reducing the water quality Increasing run-off waters will cause problems (erosion, management) Photo Tiina-Liisa Aalto
Ongoing detailed planning processes: 1 1. Niemenranta; a new housing area 2. Simola fields ; a new housing area 3. Pispala; a cultural heritage housing area (protection plan) 4. Santalahti; a new housing area 5. Rantaväylä; a traffic tunnel 6. Ranta-Tampella; a new housing area 2 3 4 5 6
Adaptation measures in land-use planning: A run-off water management plan for the Pispala esker area will be done: run-off water management orders into the detailed plans More studies and negotiations with the local environmental center about the area with artesian waters: landuse restrictions on the area? Planning orders for building and excavating to protect ground water? under discussion with the local building control authorities and environmental center Photo Tiina-Liisa Aalto
Next steps: Local rainfall and groundwater measurements and tracking Informing municipal city planners and other authorities (workshop, leaflet) Increasing local public awareness (articles, workshop, leaflets, internet) Informing the emergency services Making a regional climate change adaptation programme about to begin during this spring Photo Tiina-Liisa Aalto
Thank You! Photo Tiina-Liisa Aalto