Marlborough Sounds Resource Management Plan Fans and alluvial terraces and floodplains are infrequent but generally substantial and well-developed compared with the rest of the Sounds - largely from fluvial deposition off Robertson massif, but also apparently fault-related. Major faults through Picton and Waikawa. Infrequent or minor landforms include inter-tidal flats at the heads of major inlets (eg; Whatamango Bay), islets (Mabel), rock stacks and beaches. Generally large, high gradient streams, mostly originating on Robertson massif. Streams with long, low gradient stretches on fans and alluvial flats. Streams meandering on some of the larger, flatter terraces. 2. Climate and Elevation Temperate to cool, moist climate. Temperature inversion and cold air drainage into valleys pronounced. Light winter frosts frequent on gentle landforms; some frost-free areas. Temperate range ameliorated by marine influence but more extreme at higher altitudes. Droughts very uncommon. Rainfall range: 1200-1600 mm increasing with increasing altitude and distance from the coast. Generally sheltered from strong winds, especially in the main inlets, but Port Underwod bays exposed to southerlies. High ridges and summits of Robertson massif very exposed to winds from all directions. Winter snow on massif infrequent and ephemeral. Relatively high elevation: 0-1036 m altitude range; mean altitude 350 m. Maritime influence variable; significant influence where exposed to the south, but moderate influence in more sheltered inlets and calmer waters, especially Picton and Waikawa. 3. Water High water quality in forested catchments and headwaters. Some degradation in lower gradient stretches; significant alteration (especially channelisation) to in-stream habitat and water quality in urban parts of Waitohi and Waikawa Streams. B. The Biological Environment [Part of Para and Sounds Ecological District] Total land area of Robertson ecosystem is 11,151 ha of which; 70% is in native forest, 9% is in shrubland (both native and exotic), 13% is in pasture and 8% is in plantation forestry. (Note: Percentages based on interpretation of 1990 satellite images.) 1. Predominant Indigenous Vegetation Detailed in Table 12 Originally, predominantly forested, except for rock and beach shoreline fringes, coastal shrublands, coastal and inland bluffs, estuarine embayments, active floodplains and dune systems. Tall alluvial forest was once a significant feature of the ecosystem. App Two - 60