Why Should We Test The Water In Rivers & Tributaries?
In this Article We Explain How To Test The Water In Rivers & Tributaries Of The River Sid.
The Sid & Its Tributaries:

- Provide habitat for many different animal species living in, on and around the water. From fish to mayfly nymphs, from water measurers to dippers, from Otters to kingfishers.
- Sustain aquatic plants and bankside herbaceous plants and trees
- Create wild life corridors
- Cater for our health and well being
- Healthy rivers reflect a healthy landscape
- With decreasing frequency of statutory sampling, it is becoming more important for us to look out for our rivers.
How Healthy Is Our River?
A group of volunteers are finding out, supported by the West Country Rivers Trust [WRT], who organise this citizen science project across the SW Region.
9 volunteers monitor monthly in over 13 locations across the valley.
We will also survey Salcombe Regis Mouth and Weston Mouth, streams to the east of the Sid Valley, but within the Sidmouth political area.
What Do We Record?
We carry out 4 water tests
1. Water Temperature
- Changes with the seasons. Sid catchment range is 6C – 16C approximately.
- Temperature affects growth rate and speed of movement of invertebrates
- Colder water holds more oxygen River Sid water flows over uneven stony ground and weirs so air mixes with the water regardless of temperature.
- Toxic chemicals e.g. cadmium zinc and lead dissolve more easily in warmer water
- Aquatic creatures are less able to withstand the effect of poisons if the water temperature is higher.
- In the long term our data may reveal the effect of climate change
2. Water clarity [Turbidity] – A measure of mud in the water
How do we test for turbidity?

We look down through the water sample in a measuring cylinder at a secchi disc [20 cm disc with alternating black and white quadrants] placed at the bottom. The muddier the water the lower the volume of water needed to hide the disc.
3. Dissolved chemicals [Total Dissolved Solids – TDS]
Natural sources: calcium, magnesium and potassium from rocks & soil through which water has flowed to reach the river.

Man made sources:
- farm run off from fertilisers, pesticides, herbicides
- urban run off – pollutants from vehicles, [oil, fuel, brakes, tyres and road abrasion], garden chemicals and corroded metals.
How do we test for Total Dissolved Solids?
With a TDS meter which also measures temperature
Water is a poor conductor of electricity but the majority of particles dissolved in water carry a positive or negative charge and enable the water to conduct an electric current. This is measured in in ppm [parts per million] giving an approximate value [to an accuracy within 10%.]
The TDS in rainwater falling on 28/9/21 was 12ppm. Sid Lane tap water is 220ppm [150 – 250ppm is rated as good drinking water]
Readings for the Sid catchment vary from 55ppm
4. Phosphates
•Essential for plant and animal growth
• Human activities can add unwelcome amounts to the environment.
How to we test for phosphates?

Using a phosphate indicator strip and a colour chart. The indicator strip is put into a tiny test tube with the water sample and turned up and down 5 times. The indicator strip turns blue. The shade will vary according to the amount of phosphates present.
Essential for plant and animal growth
• Human activities can add unwelcome amounts to the environment.
To date, Phosphate values range from 0 to 300 ppb [parts per billion]
If water is very polluted the WRT can provide further tests for ammonia and nitrates.
For more on the River Sid and other projects visit https://sidvalleybiodiversity.org/category/rivers/
There is more on how to Test The Water In Rivers coming soon.