Manly Lagoon Dredging Project - Manly Council - NSW Government

Manly Lagoon Dredging Project – Review of Environmental FactorsPrepared for Manly and Warringah CouncilsThese matters are further discussed in Section 5.4.1, Section 5.4.2 and Section 5.5.2 (forheritage).5.4.1 FloraExisting EnvironmentSeagrassA recent seagrass survey undertaken by Cardno Ecology Lab in July 2009, commissionedfor this REF, indicated that no seagrass beds were present at the proposed dredginglocations. Only one seagrass species, Zostera capricorni, was found within the Lagoon, withthe nearest seagrass observed occurring approximately 500m downstream of the works.The distribution of the seagrass was from just downstream of the Pittwater Road Bridge tojust upstream of the Queenscliff Bridge, around the perimeter of the lagoon (Figure 5.9).The report also concluded that seagrasses appeared to be in relatively healthy conditiondespite the presence of epiphytic algal growth on leaves which is indicative of high nutrientlevels in lagoon water, and that no seagrass was observed below 1m in depth. The fullreport is contained in Appendix G.Figure 5.9: Aerial Photograph Showing the Distribution of the Seagrass Zostera capricorni in ManlyLagoon, 17 July 2009.Previous seagrass studies and mapping undertaken by The Ecology Lab (2004) in 2002 and2004 and UTS (2004) generally concur with these results, indicating only one seagrass2 July 2010 Cardno (NSW/ACT) Pty Ltd 71H:\Doc\2010\Reports.2010\Rep2580v4.doc