Isotope mixing scenarios for: To what extent are the source mixing models accurate: evaluation of the model accuracy and guidelines for the site-specific model selection

<p><span>We selected 10 types of distinct isotope signatures that can be found in the samples of natural water. Every 3–10 types of hypothetical isotope signatures were conceptually grouped together. There would be 968 possible combinations based on combinatorics theory. However, we needed distinct mixing polygons to facilitate our determination of model capacity in dealing with uncertainties. Therefore, we </span><span>kept </span><span>only 240 such groups in </span><span>the </span><span>final</span><span> analysis</span><span>. Each group was designated with a </span><span>predefined</span><span> mixing ratio. After that, we ran all the examined models through these mixing scenarios to </span><span>obtain</span><span> the model estimation of the mixing ratios.</span></p>