Research Article
The Comparison of Grey System and the Verhulst Model for Rainfall and Water in Dam Prediction
Table 3
The comparison of water in dam and relative errors of the two models from actual data gathering.
| Year | Water in dam (MCM) | GM(1,1) | Grey Verhulst model | Comparison | Forecasted | Relative error | Forecasted | Relative error | Precise model |
| 2005 | 438 | 438.0000 | 0.0000 | 438.0000 | 0.0000 | A | A∗ | 2006 | 1627 | 1697.094408 | 0.043081996 | 1619.2925 | 0.004737247 | A | A∗ | 2007 | 1917 | 1999.758645 | 0.043170915 | 1886.765149 | 0.015771962 | A | A∗ | 2008 | 1690 | 1762.845604 | 0.043103908 | 1653.978051 | 0.021314763 | A | A∗ | 2009 | 882 | 919.5604189 | 0.042585509 | 850.516227 | 0.035695888 | A | A∗ | 2010 | 2274 | 2372.348758 | 0.043249234 | 2258.133293 | 0.006977444 | A | A∗ | 2011 | 2145 | 2237.715356 | 0.043223942 | 2101.732322 | 0.020171412 | A | A∗ | 2012 | 510 | 531.3152594 | 0.041794626 | 469.3646272 | 0.079677202 | A∗ | A | 2013 | 1469 | 1532.194582 | 0.043018776 | 1459.992114 | 0.006131985 | A | A∗ | 2014 | 634 | 660.7303126 | 0.042161376 | 606.8758104 | 0.042782633 | A∗ | A | 2015 | 230 | 239.08772 | 0.039511826 | 218.7315064 | 0.04899345 | A∗ | A | | | MAPE | 0.042490211 | MAPE | 0.028225398 | A | A∗ |
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Source: The Thai Royal Irrigation Department.
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