Conclusion

This analysis examined uncertainty in nitrate load estimation introduced in the measurement and load calculation processes. A standard error propagation method was used to integrate uncertainty from a variety of sources to quantify the cumulative effect. Numerical simulation was used to qualify the uncertainty in load calculation process. The estimated cumulative measurement uncertainty ranged from 11.7 to 12.4%, and load calculation uncertainty for a 30-day frequency ranged from 7% expressed as CV for the largest watershed to 32% for the smallest.

Further study could examine include not only the load estimation algorithms used here (measured days – flow-weighted concentration and all days – concentration interpolated ) but also LOADEST which is more appropriate for parameters other than nitrate.

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CHAPTER 3. THE EFFECT OF WATERSHED CHARACTERISTICS ON