20.1 Evaporation from irrigation scheme
The volume for evaporation from irrigation scheme could not be quantified in a way that was complete, neutral and free from material error. Decreases to the irrigation scheme via evaporation would occur via open storages that form part of the irrigation scheme. This includes the Virginia Pipeline Scheme storage pond and the three major above-ground storages operated by the Willunga Water Basin Company. Estimates of evaporation require accurate estimates of a waterbody's surface area on a regular basis (monthly). As these data were unavailable, this line item was not quantified. Given that the storages are relatively small, decreases to the irrigation scheme via evaporation on open storages are expected to be minor and have little if any impact on the balance of the irrigation scheme balance.