Water Quality

Sample Site Description1st March8th March15th March23rd March29th March6th April
Msunduzi at Caluza bridge86640012460015290098040173290>241960
Msunduzi d/s of Kwapata129601989095909208034480141360
Msunduzi at Edendale weir bh Prison1616017230759010462036540155310
Slangspruit u/s of Msunduzi confluence816405475036090613101267046110
Msunduzi at Camps Drift bridge5172046110730241961782016690
Msunduzi u/s of Dorpspruit confluence443019505051541110007000
Dorpspruit at polo fields83601565064887270771015531
Townbush stream at polo fields20980129103448029090759010710
Dorpspruit Ohrtmann Road816401334035780>2419608164010100
Msunduzi u/s of Refuse Dump40401850189293309100
Msunduzi u/s of Darvill WWW387302187036903448129103990
Msunduzi u/s of Baynespruit48840151503130249580103180
Baynespruit at Greytown road171009804155311986320630>241960
Baynespruit231001203315531129970155310>241960
Baynespruit at Sobantu2780014390155311112001413601046200
Msunduzi u/s of Darvill Maturation river6867092080517201553108164086640
Darvill final effluent43522851851071754
Duzi d/s of Darvill Mat river12360
Msunduzi at Motorcross2187012360101406010387307980

 


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.