The Bog

The Bog is where thoughts, opinions, discussion pieces, and action converge. Influential thinkers from the water community are invited to share their insights on current or controversial water topics. Please note that the views expressed herein are those of the authors, and do not necessarily reflect the position of the Alberta WaterPortal.

Over the past several weeks we have been on a learning journey teaching us how ecologically healthy watersheds mitigate for flood flow volumes. Specifically we have learned that:

  • healthy soils rich in organic matter hold and store more water than depleted soil systems;
  • established wetlands act as sponges across the landscape absorbing surface water runoff, subsequently replenishing our aquifers while slowly releasing runoff into our streams and rivers;
  • dense riparian edges provide buffer zones that slow down high flow volumes, and at the same time, filter surface and subsurface runoff; and
  • undeveloped vegetated floodplains provide the river room to meander and attenuate flood flow volumes via established roots structures.

This has all highlighted the beneficial flood mitigation functions these ecologies offer us and led us to this final blog in the series.

We have touched on the multifunctional role these ecologies play in providing us with many other important ecosystem goods and services such as drought mitigation, improved water quality and biodiversity, erosion control, climate regulation, important habitats for aquatic and terrestrial species, and recreational spaces for humans. This is a reminder that investing in the ecological resiliency of our watersheds for flood mitigation creates many other positive feedback loops.

Alberta is home to many meandering rivers. This is seen in the way they weave back and forth across the landscape. These meandering rivers continue to move across the land as their edges erode, and during floods and high streamflow when the alluvial fan is filled with sediment forcing the water to find a new path.

Last week Commander Chris Hadfield tweeted a link to a 28 year timelapse of a meandering river in Peru. It can be seen below.

Alberta's rivers are mostly too small to see active meandering on the timelapse however you can see some meandering in the Elbow River above the Glenmore Reservoir. Let us know if you find a better example.

On February 19th and 20th Alberta Innovates - Energy and Environment Solutions put on a flood mitigation workshop that focused on flood forecasting. The WaterPortal was lucky enough to be invited to live tweet the event. Below is a summary of the first day of the workshop. In the coming weeks a more formal summary of the entire workshop will be released along with the presentations. 

Today is the first ever UN sanctioned World Wildlife Day and given the importance of wildlife to the watershed we’re happy to celebrate.

In the United States in the 1930s all the wolves in Yellowstone National Park were extinguished. Over time the area lost a great number of aspen trees, the rivers saw major erosion, and other animals began to disappear. The lack of predators led to a great imbalance that impacted the water itself.

Check out the video below to learn more about the impact of predators on the watershed. 

If you only have four minutes to spare the Oldman Watershed Council shared an excellent and similar, but shorter video on their facebook page.

Welcome back to the Rewilding Our Rivers Discussion Series. Today we will look at the role of the floodplain and the importance of designing systems that support the meandering wishes of our rivers.

A floodplain is the flat area of land along a river or stream that is subject to flooding. The width of the floodplain is dependent on the meandering amplitude of the river. It is essentially the breathing room for a river or a stream to meander, overflow, re-route and change course. Rivers will flow where they want and the floodplain is there to provide space for the river to move.

The ecosystem of the floodplain consists of native grasses, woodlands, wetlands and riparian zones. The establishment of rooted vegetation helps to absorb the force as well as the volume of rising floodwaters. The vegetation also serves to stabilize bank erosion, filter pollutants and provide habitat for animals and recreational spaces for humans. Development of impervious surfaces on the floodplain such as buildings, roads and parking lots hinder the ability of the floodplain to absorb floodwaters and at the same time speeds up runoff into streams leading to increased downstream flooding.