Timo Silver , Samuli Joensuu

Ojien kunnon säilymiseen vaikuttavat tekijät kunnostusojituksen jälkeen

Silver T., Joensuu S. Ojien kunnon säilymiseen vaikuttavat tekijät kunnostusojituksen jälkeen.

English title: The condition and deterioration of forest ditches after ditch network maintenance

Tiivistelmä

The study deals with the dimensions and condition of ditches five and ten years after ditch network maintenance in southwest Finland. The deterioration of ditches was very fast, averaging 20 cm five years and 30 cm ten years after ditch network maintenance. The shallowing of the ditches depended on the type of soil at the bottom of the ditch. There are several factors related to the deterioration of ditch condition, including: falling stones and erosion just after digging, moose paths, growth of vegetation in ditches and litterfall, clogging of culverts and shallow main ditches and unevenness of ditch bottom. The growth of vegetation in ditch bottoms is rapid and vigorous. Vegetation cover in the ditch bottoms averaged 68% five years and 100% ten years after ditch network maintenance. Our results indicate that about 25% of the ditches in southwest Finland should be cleaned again during the rotation period. We recommend the drainage ditches be re-dug to 0.9–1.1 m depth and that the main ditches be dug 20–30 cm deeper. In this way it should be possible to reduce the number of ditch maintenance operations needed at a site.

Avainsanat
ditch network maintenance

Vastaanotettu 31.10.2017 Julkaistu 1.1.2005

Katselukerrat 2905

Saatavilla http://suo.fi/article/9839 | Lataa PDF

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