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

Table 4

Results of 8 scenarios with different initial guesses of source location.

Scenario	Initial guess value	Results					Objective function value; (×10^−9)
	Guess source location; (m)	Source location; (m)	First release period; (day)	First release concentration; (ppm)	Second release period; (day)	Second release concentration; (ppm)
1	(250, 90, −3)	(110, 270, −9)	178.90	100.14	180.04	49.99	6.035
2	(250, 90, −21)	(110, 270, −9)	180.25	99.65	179.41	49.92	6.053
3	(250, 130, −3)	(110, 270, −9)	177.38	100.91	180.14	50.01	7.483
4	(250, 130, −21)	(110, 270, −9)	179.86	99.99	180.11	49.97	2.031
5	(290, 90, −3)	(110, 270, −9)	180.01	99.92	180.10	50.07	2.165
6	(290, 90, −21)	(110, 270, −9)	180.14	99.80	179.55	49.91	4.520
7	(290, 130, −3)	(110, 270, −9)	179.38	99.76	178.53	49.78	9.155
8	(290, 130, −21)	(110, 270, −9)	180.19	99.90	179.58	50.02	4.145

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.