Skip to main content.

8. Appendix 2. Summary statistics for annual mean and maximum percentage cover by obvious periphyton mats and filamentous algae at 73 NRWQN sites for the period 1990-2006

    No. of obs % of visits with no obs Mean Mean annual maximum  Maximum
Site Visits Fil Mat F+M Fil Mat F+M Fil Mat F+M
AX1 202 177 12 4 3 7 15 19 26 100 86 100
AX2 202 143 29 1 0 1 6 0 6 20 2 20
AX3 202 138 32 0 1 1 2 6 8 13 79 79
AX4 201 154 23 12 15 27 42 49 63 77 96 96
CH1 204 198 3 1 4 5 9 28 35 55 76 76
CH2 204 196 4 2 5 8 11 34 40 69 87 100
CH3 204 196 4 0 2 2 5 16 20 50 57 100
CH4 204 195 4 0 2 2 4 17 21 24 77 100
DN1 208 96 54 4 8 12 16 23 31 57 62 72
DN2 208 178 14 3 8 12 14 33 36 46 68 68
DN3 208 143 31 12 3 15 50 17 57 96 63 96
DN4 208 91 56 2 2 4 8 12 20 54 59 82
DN5 208 123 41 8 10 18 32 29 53 90 96 96
DN6 208 154 26 1 1 2 6 7 13 88 40 88
DN7 208 166 20 0 1 1 2 7 8 17 48 55
DN8 208 134 36 5 6 11 26 24 40 55 57 85
DN9 208 127 39 4 5 9 18 18 33 100 98 100
DN10 208 199 4 24 14 38 56 50 74 100 99 100
GS1 209 50 76 7 17 24 14 34 41 54 87 95
GS2 209 181 13 4 6 10 18 30 38 56 67 76
GS3 209 152 27 7 7 13 31 36 56 81 77 100
GS4 208 119 43 6 10 16 25 38 53 71 94 95
GY1 204 130 36 2 4 6 8 18 24 18 87 87
GY2 204 133 35 6 5 11 20 20 35 87 95 100
GY3 204 166 19 3 4 7 13 18 27 49 72 98
GY4 202 144 29 1 3 4 6 12 16 22 55 58
HM1 204 155 24 1 1 2 3 8 10 24 27 27
HM2 204 84 59 5 12 18 15 32 41 55 83 83
HM3 204 178 13 5 4 10 20 19 33 67 58 69
HM4 204 141 31 5 7 11 19 30 36 55 71 80
HM5 204 124 39 2 1 3 9 5 13 61 40 61
HM6 204 187 8 26 16 42 69 47 80 100 82 100
HV1 204 198 3 0 0 1 4 1 5 46 12 46
HV2 204 194 5 17 2 19 61 10 62 100 88 100
HV3 204 185 9 4 0 4 22 2 22 62 28 62
HV4 204 194 5 0 0 0 2 2 3 21 25 29
HV5 204 162 21 3 0 3 10 0 10 67 1 67
HV6 204 194 5 0 0 0 0 0 0 6 0 6
NN1 209 164 22 2 9 11 14 50 60 79 97 100
NN2 208 189 9 0 1 1 0 10 10 1 66 66
NN3 209 173 17 0 1 1 3 6 8 23 30 40
NN4 209 167 20 6 9 15 34 38 64 94 100 100
NN5 209 172 18 0 3 4 5 20 24 40 72 82
RO1 203 177 13 6 1 7 27 10 30 48 41 48
RO3 203 156 23 1 14 14 3 36 37 9 68 68
RO4 203 145 29 2 15 17 12 47 51 65 98 98
RO5 203 100 51 3 5 8 14 14 25 44 43 57
TK1 204 182 11 6 4 10 26 20 37 100 100 100
TK2 204 171 16 3 4 7 17 23 37 85 100 100
TK3 204 186 9 6 11 18 26 39 50 91 90 100
TK4 204 104 49 4 1 5 8 6 10 100 61 100
TK5 204 190 7 13 7 20 40 34 55 100 100 100
TK6 204 65 68 1 0 1 2 1 4 24 8 32
TU1 209 117 44 24 19 43 60 57 78 99 86 100
TU2 209 179 14 21 12 33 56 35 66 95 91 100
WA1 208 137 34 9 8 17 32 28 49 75 80 97
WA2 208 196 6 0 0 1 1 3 4 10 7 10
WA3 208 161 23 4 2 5 14 8 20 56 17 73
WA4 208 116 44 2 4 5 7 10 16 35 3 35
WA5 208 156 25 5 3 8 24 13 29 86 25 86
WA6 208 157 25 5 2 7 25 9 31 70 8 70
WA7 208 150 28 13 3 16 45 10 51 76 27 80
WA8 208 129 38 4 3 7 16 15 26 65 36 65
WA9 207 139 33 12 2 14 49 11 54 100 37 100
WH1 204 187 8 2 0 2 13 1 14 67 13 67
WH2 204 143 30 9 5 14 48 24 63 100 100 100
WH3 204 79 61 27 1 27 57 3 57 95 58 95
WH4 204 75 63 25 1 25 57 2 59 100 33 100
WN1 204 179 12 5 13 18 28 53 66 87 88 100
WN2 204 193 5 0 0 0 0 0 1 4 4 5
WN3 204 148 27 3 3 6 14 19 28 43 90 90
WN4 204 129 37 3 4 8 17 22 37 79 64 100
WN5 204 192 6 0 0 0 2 2 4 16 16 32
Mean     25.4 5.7 4.9 10.6 20.4 19.6 33.5 61.3 59.7 77.4
Minimum     2.9 0 0 0 0 0 0 1 0 5
Maximum     76.1 27 19 43 69 57 80 100 100 100
Median     23 4.0 3.0 8.0 15.0 18.0 33.0 65.0 66.0 86.0
% sites > guideline       0.0 0.0 2.7 23.3 0.0 32.9 78.1 56.2 86.3

Note: Number of observations (‘No. of obs’) is the number of monthly samples that were obtained within the 17-year period for both filamentous and mats and the combination of these two. ‘Mean’ is the mean of annual mean per cent cover. ‘Mean annual maximum’ is the mean of the maximum monthly per cent covers for each year (Fig. 3). ‘Maximum’ is the absolute maximum per cent cover recorded over the 17-year period (Fig. 3). Fil = filamentous. F+M = both filamentous and mats. Bold values exceed MfE guidelines for aesthetic and recreational effects for filamentous algae or mats (Biggs 2000) for total periphyton cover proposed in this report.

 

|