Water Resources and Environmental Hydraulics · Groundwater Resources · 2 marks · Numerical answer
A leaking waste tank maintains .5 mg/L contaminant. A well is 2 km away;effective travel speed .4 m/day. First-order contaminant half-life10 years. Find steady concentration at the well in mg/L, to two decimals.
Advective time=2000/.4=5000 days. Taking365 days/year, half-life=3650 days. Concentration $C=.5\,2^{-5000/3650}=.19347$ mg/L, or **.19 mg/L**. Steady source conditions do not eliminate decay during each parcel’s travel time.
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