Why is Swimmability so important?
Why is swimmability so important?
Swimming in streams, rivers and lakes is a kiwi tradition and something we have all done. Recent water quality concerns have made us second guess jumping into our favourite water bodies.
Increasing pressure on our natural resources have caused a variety of issues that impact our waterways and make them potentially unsafe to swim in. Majority of the impacts that effect swimmability also effect ecosystem health. This means that swimmability can also be used as a proxy for general aquatic health.
What makes a stream swimmable?
Generally, people judge swimmability on the appearance of the waterbody. Common visually cues used for this include water clarity, smell, muddiness, and algal growth.
These visual attributes can be described using water quality parameters such as turbidity, nitrate, dissolved oxygen, chlorophyll, conductivity, pH and E. coli.
From a water quality perspective, a waterbody must meet certain guideline values for E. coli and cyanobacteria to be safe for human contact.
The characteristics used to assess swimmability are also important indicators of general stream condition and similar water quality parameters are used to gauge ecosystem health.
What effects swimmability?
The characteristics typically used by people to define swimmability are often a response to catchment pressures. Various contaminants from the land wash into our waterways where they can have significant environmental effects.
Nutrients and sediment from agricultural activities impact water clarity, create muddy streams and contribute to excessive algal growth, including cyanobacteria which can be toxic. E. coli from livestock and ineffective wastewater infrastructure create human health issues and are associated with high ammonia concentrations.
Metals and other chemicals from urban areas can create toxic conditions in streams, these conditions can make the stream unusable by both native aquatic species and humans.