Water Quality

Sample Site Description1st Feb8th Feb15th Feb22nd Feb
Msunduzi at Caluza bridge241960173290126700173290
Msunduzi d/s of Kwapata517200521004260077010
Msunduzi at Edendale weir bh Prison209800669003090098040
Slangspruit u/s of Msunduzi confluence3441005810021100>24196
Msunduzi at Camps Drift bridge547509820633032550
Msunduzi u/s of Dorpspruit confluence72700231009802224
Dorpspruit at polo fields1710019900529013960
Townbush stream at polo fields122302419601340023820
Dorpspruit Ohrtmann Road148307540034480051720
Msunduzi u/s of Refuse Dump866401664031102650
Msunduzi u/s of Darvill WWW155310272021602980
Msunduzi u/s of Baynespruit141360489030902990
Baynespruit at Greytown road19180017230039900>241960
Baynespruit30760019890018700241960
Baynespruit at Sobantu143900517200770100648800
Msunduzi u/s of Darvill Maturation river17329025600517206570
Darvill final effluent24196046522373
Duzi d/s of Darvill Mat river15150
Msunduzi at Motorcross1553106300196804500

 


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.