Research Design and Methods

Salt Balance Study

Water inputs and exports will be monitored for 2 years to determine the water balance for the tract. Water samples will be analyzed for the following elements/constituents:

  • total suspended solids (TSS), pH, EC, and temperature (in field)
  • dissolved NO3-, NH4+, P, Ca, Mg, K, Na, Fe, Zn, Al, Mn, S, and Cl.
  • total N, P, Ca, Mg, K, Na, Fe, Zn, Al, Mn, and S.

Irrigation return flows and streams are monitored according to the following priorities:

  • 7 primary sites with automated flow monitoring and automated temporal composite sampling
  • 7 secondary sites with automated flow monitoring and weekly grab samples
  • 8 tertiary sites with weekly flow measurement and weekly grab samples

 



 

 

Multiple Watershed Studies
Six sub-basins within the Twin Falls Irrigation Tract were selected for intensive monitoring. Sub-basins were selected to represent a broad range of irrigation practices while minimizing other variables affecting water quality. Sub-basin outlets are equipped with automated flow monitoring instrumentation and an automated sampler that collects 3 to 5 flow-weighted composite samples each week (each sample is a composite of 10 sub-samples). Irrigation water is sampled weekly and Canal Co. records are used to determine irrigation quantity.
Relative distribution of irrigation practices among 6 sub-basins chosen for detailed monitoring
 

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