Experience exchange trip to river restoration sites in the Netherlands
On September 12 – 16', staff of the LIFE+ project DVIETE visited several river restoration sites in the Netherlands. The field trip was organised by our Dutch project partner 'ARK Nature'. DVIETE LIFE+ project was represented by Edmunds Račinskis, Ilze Vilka and Zaiga Brača from the Latvian Fund for Nature, Benita Štrausa from Ilūkste municipality, Inese Vilciņa from the Institute for Environmental Solutions, Ieva Ūbele and Kaspars Goba from 'Elm Media', as well as the expert of hydrology from the University of Daugavpils Dāvis Gruberts.
After a short meeting with Frank Zanderink and Ans ter Voert within the office of 'ARK Nature', project group left for the first, earliest project site 'Gelderse Poort' in the South-Eastern part of Holland, province of Gelderland at the rivers Waal and Rijn, where Johan Bekhuis from 'ARK Nature' met the visitors. In total the area of 300 ha is left for nature development in the floodplain of Waal river, where natural landscape is being made by 'Konik' horses and cattle. During the last 50 years clay is extracted in the area, thus ponds of different age are represented here, making investigations of their natural development possible. During floods the ponds are connected with rivers. Invasive Indian Balsam Impatiens glandulifera covers large areas. Wall is regulated and it serves as internationally important waterway – about 500 ships cross the area every day. By the way, the origin of the name of currently fully regulated river is connected with its original meanders. The largest sandy dune at a river in the Netherlands is located within the project area. Trees of a native species - Black poplar Populus nigra -, grow nearby, both fully-grown and recently sprouted, indicating their ability to regenerate here. Naturally growing trees on riverbanks were not characteristic for the Netherlands for a long time, and the society has to be accustomed to them again. As a sign of naturalness, sea-hollies Eryngium maritimum, characteristic for the region, are widespread in floodplain meadows.
In the afternoon the report with recommendations on restoration of Dviete river, prepared by Dutch colleagues after their visit to Dviete floodplain in May, 2011, was discussed with Leo Linnartz from 'ARK Nature', Alphons van Winden and Daphne Willems from the company 'Stroming', working within the field of river restoration hydrology.
The next day project staff visited the second of two most important project sites of 'ARK Nature' – 'Grensmaas' in the province of Limburg. The site includes river Maas and its valley. Hettie Meertens ('ARK Nature') was a guide here. Gravel riverbed is characteristic to Maas, unlike the Waal. The project here includes both economical activity – gravel mining, and environmental issues - minimising flood risk and creation of more natural landscape of river valley. Gravel mining opens space for flood water accumulation in the newly created valley, reducing flood risks to settlements outside of river dikes. As an original monument for trees, once grown in the river valley, ancient tree-trunks, found in the sediments of river valley, have been erected here and in other project sites of 'ARK Nature' as well.
In the afternoon project group visited another site of nature restoration – 'Kempen-Broek' within the province of Limburg, at the Belgium border. Denis Frissen ('ARK Nature') introduced with the site. Like other sites, 'ARK Nature' with support from the state had purchased lands from their owners to leave them for natural regeneration. Wet forests, springs and small streams were characteristic for the site naturally. As an example of current complicated hydrological system and intensity of drainage, is a site, where ditches cross in two levels (lower flowing through a pipe).
During the last day, project group visited an area near Arcen (province of Limburg), were restoration project is implemented in former river valley. The guide was Hans de Mars, representing consultancy company 'Royal Haskoning'. Newly-created wetland once was a river valley, later degraded by regulation of the river. Nowadays the river, running through agricultural lands of Germany and Netherlands, is so polluted, that it was not restored in its original site and form, but moved aside from the restored wetland which is fed by groundwaters.
At the end of the trip project staff visited to sites at the river Molenbeek. Meanders of the river are restored in several its sections. Unfortunately, there was no possibility to establish grazing areas there, therefore river banks are intensively overgrown with herbs and bushes.
The trip was useful to become aware of 'ARK Nature' tremendous work, trying to make more natural the sites, were almost nothing of nature has left, and to value possibilities of habitat restoration and conservation in Latvia. Experience of the Netherlands in hydro-technical works of river restoration is very useful for current planning of Dviete river restoration. The trip allowed to appreciate nature values of Latvia and to understand, how crucial, under better economical situation in future, is to avoid such level of nature alteration, which the Netherlands were going through.