How would you compare the results of the different models and forecasts to select the appropriate constraints?
In the initial plot of the river data, is there something that could be used to foresee the seasonality and/or trend immediately without breaking into components?
When, how, and why?
While the automated selection provided ARIMA values, how would you select the different parameters?
How would you decide on the different modeling techniques used for your dataset?
Several of the forecasts involved negative values for the river flow. How can that be avoided?
Either use a time series that you have available or find one that has the components addressed in the chapter and apply the analysis available in R.