1 For example: During a tidal cycle, consider a measured inflow of 105 acre-ft that was actually 100 acre-ft (5 percent error) and a measured outflow of 90 acre-ft that was actually 95 acre-ft (-5 percent error). The true net flow into the bay is 5 acre-ft, but the net flow based on measurements is 15 acre-ft. The error in measured net inflow during the tidal cycle is 200 percent.