PROJECT DESCRIPTION
BACKGROUND
The Kraenepoel near Aalter is one of the remnants of the once desolate lands of the Bulskampveld, dominated by heathlands, open relict woodlands, and pools. By the 19th century the pond of the Kraenepoel may well have been no more than a humid depression which largely dried up in summer. However, in this shallow and nutrient-poor lake, a unique oligotrophic aquatic fauna and flora thrived. During the 2Oth century, the water quality gradually declined. Several factors contributed to this decline, such as abandonment of the traditional water level maintenance and extensive fish farming, an increase in silt from the surrounding forest litter, the diffuse inflow of nutrients and pollutants from the intensively-used surrounding farmland and from upmarket residential subdivisions, which conveniently drained their wastewater straight into the Kraenepoel. The last survivors of the oligotrophic plantlife disappeared. Furthermore, a dyke was built cutting the lake in two. After consultation with the previous owner and the competent authorities, a management agreement was concluded for the southern half of the pond in the 1980s, but it was never implemented because the municipality of Aalter did not succeed in getting effective control of the area. In 1996, however, the municipality acquired the southern half and concluded agreements with the owner of the northern half. The competent regional authorities for nature conservation (AMINAL-Natuur) were brought in as a partner to restore this biotope and this collaboration between private landowner, municipality and Flemish Region created the preconditions to restore the Kraenepoel.
OBJECTIVES
In order to restore the nutrient-poor conditions, the beneficiary had to achieve two results: internally, the removal of silt deposited over the years in the lake, and externally, control of the water level/quality to stop further input of polluted and nutrient-enriched water into the lake. To achieve optimum control of the water level, two constructions to regulate the in- and outflow of water were to be built, together with a temporary re-routing of the feeder rivulet Bloembeek. The next measure was to dredge the accumulated sediment from both parts of the pond. Also, the beneficiary planned to restore the reed fringes and to clear the non-native trees along the pond as an additional measure to restore the water quality. Simultaneous to this LIFE project, the regional water authorities (AMINAL-Water) and the provincial authorities planned wastewater treatment and sewer reticulation works in the vicinity, so as to end the diffuse pollution of the site.
RESULTS
The project achieved its objectives: - preparatory research was carried out concerning the seed bank, macro-invertebrates, protists, zooplankton, fish and macrophytes in the site (partly with additional funds parallel to LIFE); - the entire lake was dredged (partly with additional funds parallel to LIFE); - the Bloembeek feeder rivulet was re-routed, following the acquisition of use rights to 0.2 ha. of land, so that polluted water no longer enters the lake; - an inflow and an outflow construction, with a fish-trapping device, were built to allow water levels to be controlled; - part of the dyke bisecting the pond was removed to restore connection between the two halves (with additional funds parallel to LIFE); - scrub and all non-native trees around the lake were removed to reduce eutrophication of the water by falling leaves and to increase the amount of light reaching the lake; - pond edges were restored with limestone in the northern part of the lake; - information panels were erected; - a monitoring system was put in place for tracking future ecological developments. The first vegetation association expected to expand as a result of the habitat restoration works are pond weeds of the Magnopotamion association. The restoration of the Kraenepoel proved technically more difficult and expensive than initially foreseen but thanks to an effective involvement of the regional competent conservation authorities (AMINAL-Natuur), the Commission for Monuments and Sites of the Regional Flemish Government and several scientists, these challenges were overcome. Completion of the sewer system and treatment of the water which would normally enter the lake via the Bloembeek is planned by the municipality of Aalter as part of its integral watercourse management for the Kraenepoelloop catchment. The project achieved its objectives: - preparatory research was carried out concerning the seed bank, macro-invertebrates, protists, zooplankton, fish and macrophytes in the site (partly with additional funds parallel to LIFE); - the entire lake was dredged (partly with additional funds parallel to LIFE); - the Bloembeek feeder rivulet was re-routed, following the acquisition of use rights to 0.2 ha. of land, so that polluted water no longer enters the lake; - an inflow and an outflow construction, with a fish-trapping device, were built to allow water levels to be controlled; - part of the dyke bisecting the pond was removed to restore connection between the two halves (with additional funds parallel to LIFE); - scrub and all non-native trees around the lake were removed to reduce eutrophication of the water by falling leaves and to increase the amount of light reaching the lake; - pond edges were restored with limestone in the northern part of the lake; - information panels were erected; - a monitoring system was put in place for tracking future ecological developments. The first vegetation association expected to expand as a result of the habitat restoration works are pond weeds of the Magnopotamion association. The restoration of the Kraenepoel proved technically more difficult and expensive than initially foreseen but thanks to an effective involvement of the regional competent conservation authorities (AMINAL-Natuur), the Commission for Monuments and Sites of the Regional Flemish Government and several scientists, these challenges were overcome. Completion of the sewer system and treatment of the water which would normally enter the lake via the Bloembeek is planned by the municipality of Aalter as part of its integral watercourse management for the Kraenepoelloop catchment.