A photo of water quality where the Appomattox meets the James River. Based on the murkiness of the water, we can tell that turbidity levels are much higher in the James River.
This week, we’re shining a spotlight on Turbidity, an important indicator our James River Watch volunteers measure every week from Memorial Day to Labor Day at each of our monitoring stations. You might notice the river looking clear one day and cloudy the next – that cloudiness is turbidity! In our James River Watch conditions map, we measure turbidity as NTU (Nephelometric Turbidity Units).
So, what exactly is turbidity? Simply put, turbidity is a measure of how cloudy or hazy the water is. It’s caused by tiny particles suspended in the water, like dirt, silt, mud, algae, or even microscopic organisms. When there are a lot of these particles, light can’t pass through as easily, making the water appear murky. Higher NTU values mean murkier water.
For context, NTU scores under 10 are generally considered low and clear water, while scores over 100 are usually indicative of a significant pollution event. For the entire 2024 testing season, the average turbidity score across our watershed was 5 NTU. This week’s results will show if we are above or below that average.

James River Watch volunteer, Gareth, testing for turbidity in Scottsville.
Why does turbidity matter for river health?
High turbidity can have several negative impacts on the James River:
- Blocks Sunlight: Murky water prevents sunlight from reaching underwater plants, which are crucial for producing oxygen that fish and other aquatic life need to survive.
- Smothers Habitat: Settling particles can cover and smother the riverbed, destroying vital habitats for insects, fish eggs, and small organisms. Atlantic Sturgeon, currently an endangered species in the James, rely on a rocky river bed for spawning. This sediment pollution reduces their ability to reproduce in the James.
- Affects Aquatic Life: Fish might struggle to find food or breathe when their gills get clogged with sediment. It can also make it harder for predators to spot their prey.
How do we influence the river’s turbidity?
While natural events like heavy rain stir up sediment and temporarily increase turbidity, human activities also play a significant role:
- Runoff from Land: When rain flows over exposed soil from construction sites, agricultural fields, or even bare patches in our yards, it carries dirt and sediment directly into storm drains and then into the river.
- Erosion: Weakened riverbanks, often from lack of vegetation or strong boat wakes, can erode and contribute large amounts of soil to the water.
- Pollution: Certain pollutants (like Phosphorus or Nitrogen) can also contribute to turbidity or fuel algal blooms that make the water cloudy.
What Can YOU Do to Help?
Even small actions can make a big difference in reducing turbidity:

- Plant Trees and Native Plants: Especially along riverbanks, streambanks, and in your yard, plants help hold soil in place and filter runoff. If you live in the James River Watershed and have a stream running through your property, check out JamesRiverBuffers.org to sign up for a planting on your property!
- Reduce Impervious Surfaces: Consider permeable pavers or rain gardens in your yard to allow water to soak into the ground instead of running off. Visit RiverHeroHomes.org to learn about other simple actions homeowners can take to make a big difference!
- Support Smart Growth: Advocate for development practices that minimize land disturbance and control stormwater runoff.
- Proper Waste Disposal: Prevent litter and pollutants from entering storm drains, as they can also contribute to the particles in the water.
We invited you to explore turbidity at one of the 38 monitoring stations across the James River on the James River Watch website from Memorial Day to Labor Day!