Testing The Water In Local Rivers & Tributaries

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:

Water Monitoring Of West Country Rivers Takes Place Every Week

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?

▪ General characteristics of the river channel: width, water depth,

▪ Rate of river flow,

▪ Character of the river bottom

▪ Land use on the adjacent banks

▪ Invasive species such as Himalayan balsam and Japanese Knotweed.

▪ Visible wild life present in and around the water e.g. wagtails, dippers, kingfishers, water measurers, fish, perhaps even otters.

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

• In good weather the Sid is very clear

• After rainfall brown soil muddies the water

• After heavy rainfall, red soil from our hillsides flows into the river and on to the sea. Our life’s blood, the soil which sustains us, is draining away. This is not sustainable

• Mud in the water – less light reaches aquatic plants

• Mud on the river bottom smothers the gravel, which is home to many aquatic insects and where fish lay their eggs.

How do we test for turbidity?

a measuring cylinder at a secchi disc helps Test The Water In Rivers — A Measuring Cylinder Complete With A Secchi Disc

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.

TDS Meters Also Take The Temperature & Helps Test The Water In Rivers — TDS Meters Also Take The Temperature

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.

• Algae respond with rapid growth and in still water areas this prevents light reaching aquatic plants.

• Oxygen levels are lowered – bad news for fish and most aquatic invertebrates.

• One of main sources in the Sid Valley is fertilisers and slurry run off from farms. Good land management can make a difference.

How to we test for phosphates?

A phosphate indicator strip and colour chart is used to 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.

• Algae respond with rapid growth and in still water areas this prevents light reaching aquatic plants.

• Oxygen levels are lowered – bad news for fish and most aquatic invertebrates.

• One of main sources in the Sid Valley is fertilisers and slurry run off from farms. Good land management can make a difference.

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.

On October 4, 2021 By Stefan Drew