Wetland vegetation monitoring, 1998 survey: Gnangara wetlands

Water regimes, both groundwater and surface water components dil'ectly effect distribution, health and species composition of wetland fringing vegetation. In the area of the northern Swan Coastal Plain overlying the Gnangara groundwater mound, wetland water levels and therefore the vegetation can be intimately connected to underlying groundwater levels. The Water Corporation (formerly Water Authority of Western Australia) has been drawing water from the Gnangara mound for domestic water supply for a number of years. The main objective of this study is to monitor the changes in the vegetation fringing these wetlands and to determine if this is related to changes in groundwater or other factors affecting the lakes. Wetlands of specific interest in 1998, because of breached guidelines for groundwater drawdown through abstraction, have been summarized in detail in this report. These wetlands include Lakes Joondalup, Jandabup, Mariginup and Nowergup. Raw data from the 1998 survey for the other wetlands monitored in 1997, as well as the wetlands mentioned above, are presented in Appendix 1...