Okla. Admin. Code § 785:20-13-1
The following words and terms, when used in this Subchapter of this Title, shall have the following meaning, unless the context clearly indicates otherwise:
"12-month cumulative inflow" means the sum of monthly inflow.
"Conservation pool" means a lake level elevation above the National Geodetic Vertical Datum of 1929 of 1,411feet for Tom Steed Reservoir and 1,559 feet for Lugert-Altus Reservoir.
"Monthly inflow" means, absent of stream gage data, the monthly change in lake volume calculated using lake elevation, plus the volume of evaporation, plus the volume of water used from the reservoir, plus the volume of water released downstream from the reservoir, plus (for Lugert-Altus Reservoir) the volume of seepage from the dam.
"Palmer Drought Severity Index" means a standardized index, developed and maintained by the National Oceanic and Atmospheric Administration ("NOAA"), based on a simplified soil water balance and estimates relative soil moisture conditions. The magnitude of PDSI indicates the severity of the departure from normal conditions.
"Standardized Precipitation Index" means a widely used index, developed and maintained by National Oceanic and Atmospheric Administration ("NOAA"), to characterize meteorological drought on a range of timescales.
Okla. Admin. Code § 785:20-13-1