Case Kuninkoja-Stormwater

investment and stormwater

programme of Turku

11.11.11Tallinn

Olli-Pekka Mäki

Management of stormwaters

Traditional

Flood prevention

Drying

Complete

Returning water cycle close to natural:

• Reduction

• Detention

• Vaporation

• Storage

• Infiltration

Based on drainage areas

Utilisation

Natural

Solutions using biodiversity:

• Green roofs

• Ponds

• Wetlands

• Biofilters

• Vegetation

Effects on scenery and waterbody

Background information

Kuninkoja –brook:

Drainage area 27 km2

Length of the main channel 7 km

Built area 30 %Fields 9 %

Forest 40 %

• Locally valuable scenery element

• Diverse habitat: bogs, meadows, groves (oak, ash)

• 10 fish species have been observed

• ~1 km of 7 km channel length is constructed area and water flows in pipes

Cluster of space demanding shops have been build in three years 2008-

2010

~ 440 000 m2

No measures taken

to delay the stormwater runoff to

Kuninkoja

Flooding has increased

Situates outside city border

Stormwater planning and investment

• Target is to – prevent the disadvantages of flooding– increase the use of surface water elements in planning and construction of parks and greenery areas– decrease rapid water level variations in brook– maintain biodiversity

• Environmental and City Planning Department responsible for planning

• Real Estate Department resbonsible for constructing and maintaining

• Budget of stormwater measure is ~ 61 000 €

• Construction during 2012

Stormwater plan

•Flood reservoir of ~2000 m3

•Planting of wetland plant species

•Meandering of channel

Thank you!

Parameter Average Range

Cond. 40 mS/m 28 - 50

pH 7,8 7,1-8

SS 7,6 mg/l <2 - 23

Coliform 2100 /100ml 770-4400

BOD7 1,2 mg/l 0,8 - 1,5

Ptot 47 µg/l 30 - 110

Ntot 1650 µg/l 1500 - 1750

Oil 0,046 mg/l

Parameter Average Range

Cond. 35 mS/m 21-44

pH 7,6 7,3-7,7

SS 15 mg/l 10-27

Coliform 68000/100ml 500-200000

BOD7 5 mg/l 1,2-8,6

Ptot 63 µg/l 54-82

Ntot 1550 1200-1800

Oil < 0.04 mg/l

Parameter Average Range

Cond. 46 mS/m 42-56

pH 8,3 7,8-9,8

SS 10,4 mg/l 5,2-21

Coliform 970/100 ml 8-2800/100 ml

BOD7 1,8 mg/l 1,2-2,3

Ptot 82 µg/l 34-150

Ntot 2320 mg/l 1400-3300

Oil 0,11 mg/l

Parameter Average Range

Cd < 0,1 µg/l

Cr 3,3 µg/l 1,3-3,6

Cu 0,01 mg/l 0,008-0,014

Pb < 1

Quality of stormwater in

Turku