Where does drawdown collide?

In hydrogeology, drawdown is the drop in water level (the lowering of the water table or piezometric surface) caused by pumping water from a well, measured as the difference between the undisturbed level and the level during pumping. It is greatest at the well and shrinks with distance, tracing a cone of depression through the surrounding aquifer. Theis's 1935 analysis related drawdown to the pumping rate, elapsed time, and the aquifer's transmissivity and storage, giving hydrologists a way to predict how far and fast the cone spreads. The referent is a change in groundwater elevation, measured in metres of head, unrelated to the financial loss that shares the word.[1]

Unit

The decline in hydraulic head, in metres, caused by pumping

Recovery means

Water levels recover toward their pre-pumping height once pumping stops and the aquifer refills

Measured by

Measured as pre-pumping head minus pumping head in monitoring wells, and modelled from pumping rate, transmissivity, and storativity

In finance, a drawdown is the decline in the value of an investment or portfolio from a previous high-water mark down to a later low, usually expressed as the percentage lost from peak to trough; the maximum drawdown is the worst such fall over a period. It captures downside risk and the pain of holding through a slump, and it drives risk limits and performance measures. Chekhlov, Uryasev, and Zabarankin built formal drawdown measures into portfolio optimisation. The referent is a loss in asset value over time, not a lowered water table, joined to hydrogeology only by the word.[2]

Unit

The percentage fall from a peak value to the following trough

Recovery means

Recovery is the climb back to the prior peak; the time it takes is the drawdown's underwater or recovery period

Measured by

Measured as the largest peak-to-trough decline in a value series, and summarised by maximum and average drawdown