The Saline-Upconing Bound Beneath a Coastal Pumping Well: The Rate at Which a Village Well Salts Itself, and the Rate That Holds the Interface Down

Applying the Schmorak and Mercado critical-discharge relation to a stated coastal well (K = 5 m/day, screen 12 m above the interface, density contrast 0.025) gives a critical pumping rate of 33.9 m3/day (0.393 L/s) above which no stable fresh-water cone exists. The recommended operating bound, holding interface rise to 0.25 of its travel, is 0.196 L/s and still meets the village demand of 5,000 L/day in 7.1 hours. The installed 1.0 L/s pump runs at 2.55 times critical and will salt the well; two wells at the safe rate deliver 11,310 L in 8 hours. The bound scales with the square of depth above the interface and is tabulated across conductivity and depth. SIMULATED, NOT MEASURED.