Coastal Restoration Trust of New Zealand

Coastal Dune Ecosystem Reference Database

Manawatu-Wanganui Region Estuaries September 2016 Horizons Report 2016/EXT/1500 Habitat Mapping Vulnerability Assessment and Monitoring Recommendations Related to Issues of Eutrophication and Sedimentation Technical Report

Barry Robertson and Leigh Stevens
Publisher / Organisation
Horizons Regional Council
habitat, Manawatu, Wanganui, estuary, eutrophication, sedimentation
As part of their coastal State of the Environment (SOE) monitoring programme, Horizons Regional Council (HRC) recently contracted Wriggle Coastal Management to identify and assess the vulnerability of the estuaries in the Manawatu-Wanganui Region to the key estuary issues of eutrophication (excessive nutrients) and sedimentation (excessive muddiness), and to recommend regional estuary monitoring priorities. Based on use of the recently developed NZ Estuary Trophic Index (ETI) toolbox (Robertson et al. 2016a, 2016b), the assessment used a combination of existing monitoring information, field visits to all of the larger estuaries, broad-scale GIS-based mapping of dominant habitat and substrate types, and modelled estimates of catchment derived sediment and nutrient loads, to produce: i. broad-scale maps of current habitat and substrate types within each estuary (ArcMap GIS dataset for 30 estuaries), ii. an assessment of both the “vulnerability” and “existing condition” of estuarine habitats to eutrophication and sedimentation, and iii. a recommended estuary monitoring programme to manage estuarine biological resources in the region.