Customised spatial climate forecasts to improve land and water management

Abstract

Use of seasonal forecasts to improve management of land and water for agriculture and the general community is sometimes limited by lack of historical data for the user's location. Customised forecasts for multiple locations may be used to examine spatial coherence of ENSO effects on streamflow in order to make maximum use of information in a region.

This paper examines the implications for availability of water for irrigated cotton production by analysing historical records from five stream gauging stations in the Condamine-Balonne Basin of southern Queensland. This basin constitutes one quarter of the Murray-Darling Basin.

The overall methods were: to examine the forecasting skill available for streamflow gauging stations relevant to the irrigated cotton industry in the region; to use customised spatial seasonal forecasts in order to examine the coherence of the climatic effects in the region, and thus to make the best possible assessment of the coming season; to draw some conclusions about likely water availability from the analyses; and to examine some implications at farm level. In practice these implications will be tempered by water allocations and licence conditions.

Customised geospatial forecasts of streamflow on any scale chosen by the user can improve land and water management by providing advance warning of likely water availability, particularly during periods when the SOI is in a negative phase by early winter. Forecasts using persistence of streamflow provided useful additional skill in summer. Spatial coherence was a useful concept that improved confidence in the reliability of the forecasts. Further development of the AUSTRALIAN RAINMAN computer package will provide a convenient tool to carry out such analyses. Forecasts of streamflow can assist decision making in the irrigated cotton industry. This work could be extended to other industries and regions.