Lakes and Lakebed Cropping in the Western Division of New South Wales.

Abstract

We developed an inventory of all lakes 100 ha or greater in area in the Western Division of New South Wales including information on source of water, salinity, water regime, lake area, and presence of cultivation permits. Number, area and distribution of different categories of lakes were summarised, and the use of lakes for cropping (lakebed cultivation) and water storage were analysed by category of lake. There were 567 lakes 100 ha or larger in area in the Western Division. The majority of these were mainly dry (includes dry lakes) (56%) or filled intermittently (40%), usually from river flooding. Just under 5% of lakes were perennial. Water regimes in most perennial lakes were controlled by local structures. Seventy lakes had lakebed cultivation permits. Twenty per cent of fresh lakes that filled from a river, rather than from local rainfall, in the Western Division of New South Wales were cultivated (i.e. cropped). Eighty per cent of fresh, riverine lakes larger than 2000 ha which flood and dry intermittently were cultivated. Lakebed cropping in the Western Division of New South Wales has focused on large, fresh, lakes which fill intermittently from rivers. Use of lakes as water storages has also focused on large, fresh lakes. Conservation strategies are recommended for large, fresh lakes that flood intermittently from a river, and are not cropped or used as water storages. These strategies should be directed towards developing voluntary conservation agreements with landholders. Key words: lakes, cropping, GIS, water regimes, conservation