Salt Balance Results

 
Water Balance: Irrigation return flow was between 50 and 13% of irrigation diversions from May 22 to Sept. 10, 2005, with a total of 810 mm (over 82,000 ha) diverted and 170 mm (21%) returned.  
   

TSS Balance: Flow-weighted average TSS concentrations in return-flows were generally greater than the diverted irrigation water. However, because return-flow volume was less than the volume diverted for irrigation, there were periods where TSS load returned to the Snake River was less than TSS load diverted. From May 22 to Sept. 10, 2005, the cumulative TSS load returned to the Snake river was equal to that diverted, but average TSS concentration in return-flow increased from 29 to 140 mg L-1 compared to diverted water.

 
Dissolved P: Dissolved P (DP) concentration in irrigation return flow was greater than irrigation water at the start of the season, but by August, concentrations were equal. This is due to the increased DP in irrigation water, possibly resulting from up-stream irrigation returns.  

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