|Herstelmaatregelen in een aantal brakke watersystemen|
Fortuin, A.W. (2004). Herstelmaatregelen in een aantal brakke watersystemen. Levende Nat. 105(5): 183-184
In: De Levende Natuur: tijdschrift voor Natuurbehoud en Natuurbeheer. Stichting De Levende Natuur: Oosterbeek; Amsterdam; 's-Graveland. ISSN 0024-1520, more
Three examples of improving brackish watersystem quality in the south-west part of The Netherlands by dredging and complementary measures are given. In Katse Gat the dredging was combined with increasing the waterlevel and pumping in water out of the adjacent marine Oosterschelde to the new established level. In Flaauwers- and Weversinlaag the dredging was combined with placing seepage tubes in order to increase seepage of oligotrophic marine water from the Oosterschelde into the watersystems. Rammekenskreek is a permanently stratified watersystem due to the high salt content by seepage of the lower layer. Due to the growing formation of reefs of Electra crustulenta (Bryozoa) that block the drainage channels the upper layer has become thinner. The upper layer now mixes with the hypertrophic lower layer due to wind effects, resulting in a decreased water quality. Apart from dredging the shallow parts of the watersystem the blocking reefs were removed and a siphon-weir construction was built in order to drain the lower layer separately. The upper layer will increase to an extent, that mixing between the layers will become impossible.