An artificial catchment rainfall-runoff collecting system: Design efficiency and reliability potential considering climate change in Western Australia

Two design issues relating to an artificial catchment rainfall-runoff collecting system (ACRCS) are dealt with in this study; the first is the rainfall-runoff threshold value of an artificial catchment and the second is the definition and determination of the demand-design reliability. The rainfall-runoff threshold value of an artificial catchment, which is the critical element in determining the system efficiency, can be reduced to between 4 and 6 mm when surfaces are treated with chemical sealants. The current design threshold for south-western Australia is 10 mm. The influence of the time interval on the reliability was reinforced and the results demonstrate that monthly intervals are the most likely to provide appropriate design criteria to satisfy a targeted water demand. The potential to apply an ACRCS to arid and semi-arid areas in Western Australia (WA) is illustrated using the DAMCAT5 model to assess both the rainfall-runoff threshold values and the demand-design reliability criteria.

► The design reliability for a targeted water supply demand is assessed.
► Effect of drying climate and lower rainfalls on design reliability is evaluated.
► Three types of surface sealants to improve water harvesting efficiency are examined.
► Rainfall-runoff thresholds for artificial water harvesting system is redefined.
► Water balance model DAMCAT5 is used to assess water supply design for semi-arid areas.