Gosford City Council Historical Water Quality Review & Analysis
Gosford City Council Historical Water Quality Review & Analysis
Gosford City Council Historical Water Quality Review & Analysis
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RESULTS OF WATER QUALITY DATA ANALYSIS 3-3<br />
3.1.1.2 pH<br />
Median annual pH for the <strong>Gosford</strong> waterways is presented in Table 3.3, while mean quarterly pH is<br />
presented in Table 3.4. pH levels tend to be quite variable, although levels in the last year (2001 /<br />
2002) were generally slightly higher than previous years (with the obvious exception of Site 80:<br />
Kincumber Ck entrance).<br />
pH levels were generally higher in the coastal lagoons that the Brisbane <strong>Water</strong> sites, particularly<br />
Cockrone Lagoon. The elevated pH levels in these type of environments is generally attributed to<br />
high rates of photosynthesis by micro and macro algae.<br />
On a quarterly basis, pH levels varied considerably. The results suggest a quasi-seasonal variation,<br />
with typically higher concentrations in the summer months, and lower concentrations in the winter<br />
months.<br />
Table 3.3<br />
Annual Medians for pH<br />
pH<br />
Site No. and Location 2001/ 2002 2000/ 2001 1999/ 2000<br />
n=11 n=12 n=9 Trend<br />
Site : 77 - Booker Bay 8.51 8.11 8.10 <br />
Site : 78 - Narara Creek Entrance 8.15 7.82 7.98 <br />
Site : 79 - Erina Creek Entrance 8.22 7.93 7.80 <br />
Site : 80 - Kincumber Creek Entrance 7.59 7.70 8.00 <br />
Site : 81 - Cockle Creek 8.26 8.14 8.15 <br />
Site : 82 - Woy Woy Creek 8.23 7.74 7.78 <br />
Site : 83 - Wamberal Lagoon 8.67 8.20 8.12 <br />
Site : 84 - Terrigal Lagoon 8.48 7.97 8.17 <br />
Site : 85 - Avoca Lagoon 8.60 8.21 8.39 <br />
Site : 86 - Cockrone Lagoon 8.92 8.64 8.80 <br />
Average Rainfall at <strong>Gosford</strong> 1248mm 1038mm 1228mm<br />
Table 3.4<br />
Quarterly Means for pH<br />
pH<br />
Site No. and Location<br />
Apr – Jun Jan – Mar Oct – Dec Jul – Sep Apr – Jun<br />
2002 2002 2001 2001 2001<br />
n=4 n=1 n=3 n=3 n=3 Trend<br />
Site : 77 – Booker Bay 7.81 8.21 8.73 8.57 8.37 Seasonal<br />
Site : 78 – Narara Creek Entrance 7.47 8.06 8.59 8.28 7.88 Seasonal<br />
Site : 79 – Erina Creek Entrance 7.16 8.34 8.58 8.21 8.07 Seasonal<br />
Site : 80 – Kincumber Creek Entrance 6.97 8.26 7.86 7.72 7.43 Seasonal<br />
Site : 81 – Cockle Creek 7.61 8.22 8.57 8.37 8.40 Seasonal<br />
Site : 82 – Woy Woy Creek 7.49 7.92 8.51 8.37 7.98 Seasonal<br />
Site : 83 – Wamberal Lagoon 7.45 7.97 9.11 8.90 8.24 Seasonal<br />
Site : 84 – Terrigal Lagoon 7.38 7.73 8.57 8.57 7.97 Seasonal<br />
Site : 85 – Avoca Lagoon 7.81 7.51 9.40 8.97 8.22 Seasonal<br />
Site : 86 – Cockrone Lagoon 8.59 7.23 10.13 8.98 8.16 Seasonal<br />
Average Rainfall at <strong>Gosford</strong> 150mm 735mm 189mm 174mm 445mm<br />
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