The Lincoln Environmental Organisation (LEO) helped by LET and WaterWatch tested the Liffey stream on the 3rd May 2010. We have been testing it for the last few years. We found that from the indicator invertebrates, the water was “degraded”, the Dissolved Oxygen was only 69.9% which is “unsatisfactory”, the dissolved nitrate level was 4.0 mg/L which is 10 times worse than unsatisfactory, the dissolved phosphate levels were 0.15mg/L (anything higher than 0.5 is unsatisfactory). 

The coli count was 3281 CFU’s per 100mL, where over 2000 is counted as degraded, however the count of E.coli and salmonella was very low, which was unusual, as it is usually high. This was probably because it has been very dry with no water runoff. The water in the stream would have come from the springs.

The indicator invertebrates showed the lowest number of species we had ever seen (only 2)

Local residents, children, and visitors from Christchurch (Mr and Mrs Cargo aged 86) carried out the testing with help from the Lincoln University team and the High school LEO (Lincoln Environmental Organisation).

The results were generally very disappointing, although there was less phosphate than the previous testing, possibly because the recent rain diluted the water. The high nitrate and phosphate levels probably come from the spring water.