Table 4 Parameters for membership functions of the different indicators used in the MFWQI
From: River water quality index for Morocco using a fuzzy inference system
DO | BOD5 | COD | ||||||||||
a | b | c | d | a | b | c | d | a | b | c | d | |
Excellent | 7 | 7 | 11 | 20 | 0 | 0 | 1.8 | 3 | 0 | 0 | 20 | 30 |
Good | 4 | 5 | 7 | 7 | 1.8 | 3 | 5 | - | 20 | 25 | 30 | 35 |
Average | 2 | 3 | 4 | 5 | 3.1 | 4.3 | 5 | 10 | 25 | 35 | 40 | - |
Poor | 0 | 1 | 2 | 3 | 4.4 | 5.9 | 10 | 25 | 40 | 40 | 80 | 80 |
Very poor | 0 | 0 | 1 | 1 | 5.9 | 25 | 200 | 200 | 80 | 81 | 500 | 500 |
NH4+ | TP | FC | ||||||||||
a | b | c | d | a | b | c | d | a | b | c | d | |
Excellent | 0 | 0 | 0.1 | 0.5 | 0 | 0 | 0.03 | 0.1 | 0 | 0 | 20 | 200 |
Good | 0.1 | 0.5 | 1 | - | 0.03 | 0.05 | 0.1 | 0.3 | 20 | 200 | 1000 | 2000 |
Average | 0.5 | 1 | 2 | 2 | 0.05 | 0.1 | 0.3 | 0.5 | 1000 | 2000 | 20000 | - |
Poor | 2 | 2 | 5 | 8 | 0.1 | 0.2 | 0.5 | 3 | 2000 | 3500 | 20000 | 50000 |
Very poor | 5 | 8 | 50 | 250 | 0.2 | 3 | 20 | 20 | 3500 | 50000 | 1800000 | 1800000 |