The Kylmäojankorpi case study represents research work where water quality (dissolved oxygen, electrical conductivity, turbidity, and temperature) and stream-stage measured continuously. The existing forest wetland (c.a. 11ha), Kylmäojankorpi, is located in Vantaa city which is neighboring the capital city Helsinki. The study results show that forested wetland improves and regulates stream water quality and flow regime. The obtained knowledge can be used to estimate environmental effects from the similar type of forested wetlands in urban areas.
The in-depth description of the case study
Kristina Veidemane, BEF
NWRM(s) implemented in the case study
cool temperate moist
Mean rainfall unit
Mean runoff unit
450 - 600 mm
Average runoff coefficient
Case Study Info
Light or indepth?
Water quality inflow
Water quality inflow unit
Mean annual runoff range
150 - 300 mm
Average slope range
nearly level (0-1%)
Site surrounded by discontinuous urban fabric (112) and industrial or commercial units (121); actual site is 100% covered by vegetation (tree canopy and ground vegetation)
Monitoring impacts effects
Performance impact estimation method
Performance impact estimation information
The case study represents a research project where water quality (dissolved oxygen, electrical conductivity, turbidity, and temperature) and stream-stage measured continuously. Intermittent water samples for chemical and biochemical analysis were also taken during base flow and rainfall events for more detailed study of wetland impacts on water quality and export loads of solutes.
Design & implementations
Area subject to Land use change or Management/Practice change (ha)
This is a protected area to maintain a semi-natural forest and wetland in an urbanizing landscape. The main factors influencing site selection are thus pre-existing flow paths and historical land use.
Inflow volume unit
Outflow volume unit
Peak flow rate
Design contractual arrangement
Site protected in 2000 (given conservation area status).
The study of the water quality and flow regime was conducted within the MSc programme of the HELSINKI University
Design consultation activity
|Activity stage||Key issues||Name||Comments|
Design land use change
|Land use change type|
Lessons, risks, implications...
The Kylmäojankorpi case study represents a research work which aimed to assess whether and how existing forested wetland improves and regulates stream water quality and flow.
|Success factor type||Success factor role||Comments|
The main purpose was to retain a semi-natural forest in a rapidly urbanizing suburb of Helsinki.
|Barrier type||Barrier role||Comments|
|Driver type||Driver role||Comments|
|Financing share type||Share||Comments|
Policy, general governance and design targets
The study monitored a forest wetland, Kylmäojankorpi, in Vantaa city. Because of the large amount of land sealing surrounding the wetland, there are potential problems with flashy runoff and water quality.
Part of wider plan
|Pressure directive||Relevant pressure|
|Policy area type||Policy area focus||Name||Comments|
|Impact directive||Relevant impact|
Policy wider plan
|Wider plan type||Wider plan focus||Name||Comments|
Policy requirement directive
Direct benefits information
The economic benefits from maintaining forest wetland in urban areas have not been estimated.
Costs investment information
this is not relevant
Costs operation maintenance
this is not relevant
Costs total information
this is not relevant
Ecosystem improved biodiversity
Information on Ecosystem improved biodiversity
The protected area and wetland complex will provide more natural habitat and may contribute to meeting Habitats Directive requirements.
Ecosystem provisioning services
Ecosystem water supply
Ecosystem impact climate regulation
No information available
Runoff reduction unit
Information on runoff reduction
Stream discharge (Jun †“Aug 2010) decreased, i.e. reduced runoff and risk of flooding downstream, which is housing areas
Peak flow rate reduction
Peak flow rate reduction unit
Information on Peak flow rate reduction
Mean peak flows (6 rainfall events, Jul-Aug 2010) reduced
Information on Ecosystem flood control volume
Risk of flooding downstream reduced
Water quality overall improvements
Positive impact-WQ improvement
Water quality Improvements Phosphorus (P)
Water quality Improvements (P) unit
Water quality Improvements Nitrogen (N)
Wq Improvements n unit
Water quality Improvements Total Suspended Solid (TSS)
Water quality Improvements (TSS) unit
Water quality Improvements Copper (Cu)
Water quality Improvements (Cu) unit
Water quality Improvements Zinc (Zn)
Water quality Improvements (Zn) unit
Water quality Improvements Escherichia Coli (e.coli)
Water quality Improvements (e.coli) unit
Soil quality overall soil improvements
Neutral impact-no change in SQ status