Stochastic reservoir system analysis and manufactured hydrology - a new perspective : technical paper

The Algoa Water Resources System was analyzed in 1983 and again in 1994 after a severe drought, the consequence being that the historical firm yield from the system dropped by an alarming 20 per cent. The hydrologies, both measured and manufactured (extended and patched) were put under scrutiny and with the assistance of deterministic and statistical arguments were found to be consistent. The main culprit for the apparently anomalous severe drought was an uncharacteristically low rainfall period, which, combined with an exceptional non-linearity in the rainfall-runoff relationship, spawned unusually severe critical sequences of stream-flow. The paper describes the methods adopted to achieve the diagnosis.