Go with the flow?
We all know that streams, rivers and lakes come in many different shapes and sizes.
They twist, turn, wind, bend, curve, zigzag and weave way across landscapes and have many different patterns!! No lake or stream is like any other!
Thousands and thousands of years have made rivers the unique shapes that they are….
This is a process known as erosion , which is largely responsible for shaping rivers.
Erosion loosens land as a result of physical reactions, like waves crashing into shorelines.
Even though these changes take thousands of years, they can change in the course of a single day, due to urban development.
Trent University student, Sarah Murphy, is conducting her 4th year undergraduate thesis on how changing the shape of our rivers and streams can impact the environment around them. She is working with Dr. Catherine Eimers.
Her research is focused on studying hydrology, the study of water movement in relation to the land. She wants to answer the question: how does land use alterations influence river systems concerning hydrology and geomorphology?
Sarah used data from the Water Survey of Canada that has been collected over the last 10-30 years. She ran parameters on the data and separated streams/rivers by rural and urban areas.
Sarah also used imagery and geographic information system technologies to compare the changes in the landscape. She focused on 12 water basins including Little Rouge, Oshawa, Ganaraska Region, Coburg, Nottawasaga, Etobiocoke, and Mimico.
- Extreme flows
- Richers Bakers Index (daily changes in water levels in stream channels from day-to-day)
- Stream shape
- Drainage density
Her primary results have found that urban development, like constructing new roads and buildings, may be responsible for many negative impacts to our natural environment and that agricultural impacts on streams are distinct from urban areas. For instance, agricultural landscapes are more influenced by erosion processes – but urban areas are more influenced by human development.
Changing the shape of the streams changes how the water flows. Streams naturally have many bends, which slows down how quickly the water flows.
However, in general, urban planners change the streams to flow in straight lines.
This causes the water to react in new ways – including excessive flooding, extreme flows, an increase flow of water to storm water systems, and a change in the amount of water that is drained into the ground.
Pavements have also reduced the ability of water to be infiltrated into the soils, which is increasing the potential of flooding. This is becoming a major problem in urban environments.
Some fish species and aquatic bugs aren’t able to handle these changes and they are being flushed out of their own ecosystems.
This is a big problem because in Southern Ontario, we have some of the most productive agriculture soil in all of Canada. If the topsoil is removed because of flooding, water runoff and erosion, there is a strong likelihood to increase contamination flowing into water channels from our cities.
Sarah stresses the importance of education and raising awareness about how we can begin to think about new #green ways to design our landscapes with the environment in mind.
Urban developers are urged to develop our landscape with #green practices – where both nature and urban areas can exist together.
Thanks Sarah for encouraging developers to go with the #green flow!!
Here is what she has to say about her Trent University experience: