Applying Hybrid Heuristic Approach to Identify Contaminant Source Information in Transient Groundwater Flow Systems

Table 5

Results of three scenarios when observed concentrations have measurement errors with different levels.

Scenario	Error level; (%)	Results					Optimal objective function value; (×10^−7)
		Source location; (m)	First release period; (day)	First release concentration; (ppm)	Second release period; (day)	Second release concentration; (ppm)
1	1	(110, 270, −9)	179.55	99.77	177.14	49.29	0.490
2	5	(110, 270, −9)	185.51	98.27	174.49	46.29	3.452
3	10	(110, 270, −9)	189.21	95.04	168.23	43.48	9.835

Note that the real source is located at (110 m, 270 m, −9 m); real release concentration is 100 ppm over the first 180 days and 50 ppm over the second 180 days.