In order to maintain or improve forest productivity it is necessary to clear old drainage ditches from vegetation and sediments. However, little is known about the environmental effects. In 2007 IVL and Sveaskog (Sweden´s largest land-owner) launched a new research project called DiVa in order to study the effects of ditch network maintenance on forest ecosystem. Financial support was also given by the World Wide Fund for Nature (WWF), the Swedish Environmental Protection Agency and the Swedish Forest Agency. The project examines how ditch network maintenance affects nutrients, acidity and mercury in stream water, using two different methods. Effects on benthic fauna and sediment load are also included in the project.
The goal of DiVa is to increase the scientific knowledge about the short-term effects (2-3 years) in stream water ecosystems. Furthermore, the results will be used as a basis for planning and designing methods that will minimize negative environmental effects. Finally, the results can be used for decision-making purposes at all levels by forest land-owners and the governmental.