Glossary 



Evapotranspiration A water loss due co evaporarion from 

 a water surface and consumption by veg- 

 eution. 



Exceedance Water flows, the quantity of which repeats 

 flows or is exceeded a given percentage of the 



time. If 30 acre-feet is the May 80th per- 

 centile exceedance flow, then 30 acre-feet 

 was met or exceeded 80 percent of the 

 time in May during the period the flows 

 were measured; if the period was 1 years, 

 then the 30 acre-feet flows were met or 

 exceeded 8 years (see percentile flows, 

 probability flows). 



Firm annual An estimate of the maximum volume of 

 yield water than can be released from a reservoir 



every year. It depends on reservoir inflows 

 and downstream direct flow demands. 



Groundwater Water entering a stream from its banks 

 discharge and bed. 



Losing reach A stream reach with flows decreasing 

 downstream. 



Miles City A 1914 district court adjudication of all 



Decree existing water rights on the mainstem of 



the Tongue River. 



Natural A flooding caused by overflow of a stream 



flooding channel. No diversion means are used. 



Percentile flows (See exceedance flows) 



Probability flows (See exceedance flows) 



Reconstituted Statistically created strcamflow records for 

 flows streams with no or few flow measure- 



ments. 



Retum flow Excess irrigation water returning back to a 

 stream. 



SB76 Water In 1 979 Senate Bill 76 required the filing 



right claims of all pre-1973 water rights claims with 



the DNRC by 1982. These claims are 



being adjudicated by the Montana Water 



Courc 



Seepage run A method of measuring water leaving or 

 entering a stream through its banks and 

 bed. (see groundwater discharge). 



Sub-irrigation Natural watering due to groundwater 

 dose to field surface. No diversion means 

 are used. 



Synthesized 

 flows 



Water year 



(See reconstituted flows). 



A year starting in October end ending in 

 September. It represents water runoff and 

 is used in hydrology. 



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