Ditch network maintenance (ditch cleaning and supplementary ditching), felling and site preparation may have impacts on the volumes of runoff water from forest areas. Water protection measures in forestry are an attempt to prevent an increase in leaching of solids and nutrients with runoff, and to clarify runoff as effectively as possible.
Water body load is controlled with a series of successive measures
Standard water protection measures taken by Metsähallitus include the basic structures of ditch network maintenance (silt traps, breaks in cleaning and digging, sedimentation basins), buffer zones in felling and site preparation areas, buffer strips in fertilisation as well as minor overland flows. Ditch network maintenance plans always include a water protection component.
Geographic information analysis supports water protection planning
Metsähallitus uses maps produced by the GIS application to support water protection planning. Printed maps illustrate the gradient of ditches in the target area as well as the watershed area and flow rate of the water carried by the ditches. This is also a way to estimate the erodibility of ditches and the need for various water protection measures, especially in areas of ditch network maintenance.
Watershed analysis is a method for estimating the total load caused by felling, site preparation, ditch network maintenance and fertilisation operations in a selected watershed. Furthermore, it is possible to assess how effectively various water protection measures can reduce this load. Watershed planning is used especially in sensitive areas in terms of water protection.