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In subsurface hydrogeology, drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test. In surface water hydrology and civil engineering, drawdown refers to the lowering of the surface elevation of a body of water, the water table, the piezometric surface ...
Drawdown (economics) The drawdown is the measure of the decline from a historical peak in some variable (typically the cumulative profit or total open equity of a financial trading strategy). [1] Somewhat more formally, if is a stochastic process with , the drawdown at time , denoted , is defined as: The average drawdown (AvDD) up to time is ...
In hydrogeology, an aquifer test (or a pumping test) is conducted to evaluate an aquifer by "stimulating" the aquifer through constant pumping, and observing the aquifer's "response" ( drawdown) in observation wells. Aquifer testing is a common tool that hydrogeologists use to characterize a system of aquifers, aquitards and flow system boundaries.
Well test. In hydrology, a well test is conducted to evaluate the amount of water that can be pumped from a particular water well. More specifically, a well test will allow prediction of the maximum rate at which water can be pumped from a well, and the distance that the water level in the well will fall for a given pumping rate and duration of ...
The Calmar ratio uses a slightly modified Sterling ratio – average annual rate of return for the last 36 months divided by the maximum drawdown for the last 36 months – and calculates it on a monthly basis, instead of the Sterling ratio's yearly basis. [1] Young believed the Calmar ratio was superior because. The Calmar ratio changes ...
Sterling ratio. The Sterling ratio ( SR) is a measure of the risk-adjusted return of an investment portfolio . While multiple definitions of the Sterling ratio exist, it measures return over average drawdown, versus the more commonly used max drawdown. [citation needed] While the max drawdown looks back over the entire period and takes the ...
Project Drawdown. Project Drawdown is a climate change mitigation project initiated by Paul Hawken and climate activist Amanda Joy Ravenhill. The main principles of the project are to: Reduce sources by bringing emissions to zero and stopping pollution. Support sinks and uplift nature's carbon cycle. Improve society by fostering equality for all.
The specific storage is the amount of water that a portion of an aquifer releases from storage, per unit mass or volume of the aquifer, per unit change in hydraulic head, while remaining fully saturated. Mass specific storage is the mass of water that an aquifer releases from storage, per mass of aquifer, per unit decline in hydraulic head: where.