Management & restoration
Freshwater habitats are delicate environments,
often harder to care for than land habitats. To help drive the
conditions that keep them in pristine order, there exists a
constant thirst for a steady supply of clean fresh water - a need
that must be satisfied on time, and delivered to order. Threats
from humanity, pollution and invasive species mean that – once the
damage is done – recovery can be a slow and painstaking
For example, rivers depend on winter flooding
to scour away silt. Sharp rises in river level encourage migratory
fish to move upstream. Low water levels are also important – plants
such as bladderwort and floating water plantain flower during these
drier periods. Freshwater dynamics are complex - shifting and
shivering within the year.
All freshwater habitats are fed by rainfall
from the surrounding land. The rainfall may run directly into
streams, or it can percolate slowly, patiently sifting through soil
and porous rocks and entering rivers and lakes as groundwater.
During this process it dissolves or mixes with
many other substances. Mopping up minerals and nutrients from the
soil, oils from road surfaces, tannins from leaf matter and
particles of debris and silt.
This means that the water in our rivers and
lakes effectively mirrors the use of the surrounding
As ever, human activities such as water
abstraction, sewage discharge, flood defence, recreation and
fisheries all have direct effects on the aquatic environment.
Whilst other major threats exist in diffuse pollution and invasive
Once they have been damaged, restoring
freshwaters is often expensive, and can take a great deal of time
and careful effort.
Many upland lakes and rivers are still
suffering the ecological effects of acid rain that fell in the
1970s and 1980s, and may take a century to recover fully.
Some are also contaminated by heavy metals
such as copper, lead and tin – a legacy of the long history of
metal mining in Wales.