Ero sivun ”Harvanjärvi (04.582.1.016)/Restoration project 2009-2011” versioiden välillä
Järvi-meriwikistä
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Versio 20. tammikuuta 2014 kello 15.08
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This page describes the restoration of Harvanjärvi (04.582.1.016) – a Virhe lausekkeessa: tunnistamaton välimerkki ”,”.Virhe lausekkeessa: tunnistamaton välimerkki ”,”. lake in the Pohjois-Savon maakunta region of Finland. The restoration started in 2009 and ended in 2011. The restoration has been evaluated as successful.
Data has been collected in the LakeAdmin project with the aim of sharing good restoration practices throughout Europe. More lakes can be searched in the LakeAdmin Lake Archive.
Data has been collected in the LakeAdmin project with the aim of sharing good restoration practices throughout Europe. More lakes can be searched in the LakeAdmin Lake Archive.
Main problems and reasons for restoration
Too high density of cyprinids | |
Blooms of cyanobacteria | |
Internal phosphorus loading | |
Overgrowth of macrophytes | |
External phosphorus loading from diffuse sources Mean annual loading of phosphorus: 209 kg (field 103 kg, forest 54 kg, rural population 48 kg, swamp 4 kg) |
Main restoration and management measures
Year of implementation | ||
---|---|---|
Biomanipulation by fish removal | ||
Aeration of hypolimnion | ||
Dredging | ||
On site sewage treatment of scattered settlement Estimated reduction from waste waters 45 % |
Effects of the restoration measures
Before restoration | After restoration | ||
---|---|---|---|
Total phosphorus | 27 Median value from n measures during growing season | 24 Median value from n measures during growing season | |
Total nitrogen | 510 Median value from n measures during growing season | 450 Median value from n measures during growing season | |
Virhe lausekkeessa: tunnistamaton välimerkki ”,”. | Alkalinity | 0,26 Median value from n measures during growing season | 0,26 Median value from n measures during growing season |
Virhe lausekkeessa: tunnistamaton välimerkki ”,”. | Transparency | 1,37 Median value from n measures during growing season | 0 |
Chlorophyll-a | 23 Median value from n measures during growing season | 23 Median value from n measures during growing season |