Messing about with the river

Ten Practical Outdoor Activities for Understanding River Principles

Drawing on the principles of fluvial geomorphology, ecology, human impact, and conservation discussed in relation to the River Sid, here are ten practical outdoor activities you might undertake to further your understanding:

1. Sediment Observation and Mapping

   • Principle: Fluvial Dynamics (Erosion and Deposition). Fast-flowing water erodes and carries particles downstream, while slowing water allows sediments like sand and gravel to accumulate.

   • Activity: Walk sections where the river slows down, such as Sidford or Fortescue, and note the size and location of shingle deposits. Compare this to a faster-flowing section like Riverside Wood. This helps visualise how flow rate dictates whether the river is an eroding or depositing system.

2. Rainfall Response Monitoring

   • Principle: Catchment "Flashiness" and Runoff. The River Sid has a "very flashy" catchment, meaning water levels can rise rapidly, often causing increased runoff and high flow rates during spates.

   • Activity: Establish a safe observation point (perhaps near one of the monitoring points like Sidford or School Weir). After a period of heavy rain, observe the speed and height of the water level increase, noting the increased turbidity (cloudiness) which normally increases considerably after heavy rain.

3. Human Modification Survey

   • Principle: Anthropogenic Intervention. Human actions like straightening, armoring, and building weirs have altered the river's natural erosive processes and flow patterns.

   • Activity: Follow the river's course from a relatively natural area (like Deepway Meadow in Sidbury) down to a highly modified stretch, such as the Lower Sid where the course has been straightened and banks fortified. Note how the river channel width and bank materials change, illustrating the contrast between natural meander and confinement.

4. Riparian Habitat and Shading Assessment

   • Principle: Habitat Health and Temperature Regulation. Loss of habitat and high water temperatures are concerns. Planting trees provides shade and helps reduce flow and improve water quality.

   • Activity: Assess the extent of tree cover along different sections (riparian zones). Note where banks are exposed, which could benefit from planting to reduce soil runoff or provide shade against high temperatures. Look specifically for areas where vegetation along the banks is crucial for maintenance, given the river's flashy nature.

5. Invasive Non-Native Species (INNS) Mapping

   • Principle: Ecological Threats from Invasive Species. Species like Himalayan balsam and Japanese knotweed out-compete native plants, leading to habitat loss and reduced species diversity.

   • Activity: Walk a stretch of the river, particularly one where access is public like The Byes or Riverside Wood. Actively look for and map the presence of Himalayan balsam (widespread, infesting over 50% of the river's length) or Japanese knotweed. This directly supports the need for community action identified in the management plans.

6. Barriers to Migration Study

   • Principle: Obstruction of Aquatic Life Movement. Weirs, particularly the large School Weir, restrict upstream movement of fish, including migratory species like salmon and eels.

   • Activity: Visit School Weir. Observe the height (over six feet high) and structure of this major barrier. Consider the energy required for a fish to scale it, linking the physical structure to the recorded detriment to biodiversity (preventing passage of sea trout and Atlantic salmon).

7. Bird Species Observation (Habitat Specialisation)

   • Principle: Indicator Species and Habitat Requirements. Specific birds are adapted to fast-flowing, clean water environments.

   • Activity: Focus observations on species mentioned in the sources. Search for the Dipper, a specialist in fast-flowing streams, often seen near Fortescue. Look for the flash of the Kingfisher, whose presence suggests reasonably healthy water, especially around quiet upper reaches.

8. River Fly Invertebrate Assessment

   • Principle: Water Quality Indicators. River flies (mayflies, stoneflies, caddisflies) are used as indicators of a functioning, healthy river ecosystem.

   • Activity: If training is available (as noted for volunteers in the management plan), carry out a simple River Fly Survey to assess the population health. Even without training, you can search beneath stones in fast-flowing riffles to look for invertebrates that hide or cling to avoid being washed away, providing a hands-on look at the 'canaries in a coal mine' of the river ecosystem.

9. Coastal Dynamics Investigation

   • Principle: Interaction of Fluvial and Marine Processes. The river battles the sea at the mouth, with shingle constantly moving inwards and outwards. Coastal structures affect this natural sediment movement.

   • Activity: Visit the river mouth at different tidal phases. Observe how the shingle ridge creates a temporary barrier to the river’s path and how the river erodes the bank at low tide. Note the effect of structures like the training wall on the movement of beach material.

10. Impact of Disturbance Observation

    • Principle: Localised Human and Animal Impact. High levels of disturbance, particularly from dogs in public areas like The Byes, can negatively affect bird life and stir up the river bed.

    • Activity: Spend time observing the area of The Byes during peak hours. Note the frequency of disturbance, such as dogs entering the water, and observe if this is reflected in limited sightings of birds like grey wagtails or mallards, as suggested by the sources. This activity highlights the importance of reducing disturbance for habitat enrichment.