Solution Exercise 3
Equation (13) is used to determine minimum groundwater age. A spreadsheet showing this solution is available on the web page for this book↗.
The average precipitation‑weighted[latex]\ _{}^{3}H[/latex] for the last five years is 8.5 TU.
Agemin =[latex]\ \frac{- \ln\left( \frac{3.5}{8.5} \right)}{\left( \frac{ln(2)}{12.32} \right)}[/latex] =[latex]\ \frac{- \ln(0.4118)}{0.05626\ yr - 1}[/latex] = 16 years