Water Quality

Site3rd Sept10th Sept17th Sept23rd Sept1st Oct8th Oct15th Oct22nd Oct
uMsunduzi at Caluza Bridge27236131461134488570432046113076
uMsunduzi below Kwapata727098046488816411780613061313448
uMsunduzi at Edendale Weir2909129977270727012590410034486488
Slangspruit above Duzi confluence717036540198632419672700290903255013540
Duzi at Camps Drift Bridge20321895911371850<100365495
uMsunduzi above Dorpspruit confl488424011536314080<100365474
Dorpspruit just above Townbush stream7496241081727042600228017223654
Townbush Stream just above Dorpspruit211240032554611393063011534106
Dorpspruit Ohrtmann Road / just above Duzi confluence2180920814136155311935027230>2419617790
uMsunduzi above Refuse Dump28246115172104624570301048846867
uMsunduzi above Darvill WWW9804648868671046245003090980419863
uMsunduzi U/S Baynespruit275598043441198635730393054757701
Baynespruit at Greytown Road9208435>2419612960198630173016072489
Baynespruit behind Epol1730108601333011780261302330365412033
Baynespruit at Sobantu1210003255007701001732936540041006488001299700
uMsunduzi U/S Darvill mat river29870155310104621986314136019863072700241960
Darvill Final Effluent normal discharge site4352924111467742093286
uMsunduzi D/S Darvill mat river>2419636540
uMsunduzi at Motorcross weir364095901299724196275505120323015000

 


WHAT DO E. COLI NUMBERS MEAN?

DUCT’s River Water Quality Assessment Guidelines updated 27 October 2013

E. coli bacteria occur naturally within mammal digestive systems and most of them are not harmful in any way. However, because they are so common E. coli data are considered useful as a general indicator of a wide range of other potential human pathogens, and thus also of the possible presence of sewage related water quality problems. In the absence of other data, E. coli numbers are useful in allowing a general assessment of other potential water quality risks.

E. coli count/100mL
Water quality “assessment”
Assessment of probable risk to canoeists

*0 – 130
  WaterExcellent Excellent – Considered acceptable for full contact recreation – excellent / likely natural catchment.
Extremely low risk.

130 – 1000
WaterGood Good – within the range expected for quite good catchment conditions, but significant / increasing risk of illness if used for full contact recreation (e.g. swimming). Very low risk.

1001 – 4000
WaterFair Fair resource condition, natural sources (i.e. not sewage related) are still possibly the E. coli source, but increasing likelihood of human faecal / sewage contamination at the upper end of this range. Unacceptable for swimming. Low, but increasing risk.

4 001 – 10 000
WaterPoor Degraded – Significant faecal input or some sewage contamination is indicated. Other water quality parameters are likely to be poor.
Moderate risk (approx. 1 in 10 may get sick).

10 001 – 25 000
WaterVeryPoor Unacceptably Poor, sewage contamination definitely present.
Moderately high canoeing risk (approx. 1 in 5 may get sick) – some likelihood of illness esp. in white water.

25 001 – 50 000
WaterDangerous Bad, with significant sewage contamination and negative environmental consequences.
High risk (approx. 1 in 3 may get sick) – consider not canoeing or paddle on flat water only, with no risk of falling out.

>50 000
WaterVeryDangerous Severely contaminated with significant sewage contamination and negative environmental consequences.
Very High canoeing risk – (approx. 1 in 2 paddlers may get sick). Avoid canoeing!

*Note, the only acceptable value for drinking water quality is ZERO E.coli counts per 100 mℓ. No naturally occurring surface water should be expected to have E. coli this low (even in large dams). If zero E. coli results are achieved for a natural water, contamination by disinfectants is the likely cause and this may be masking other significant potential pollutants.