We are planning to utilise various types of flood defence to help stop the River Cole from flooding at times of high rainfall.
Flood defences are mechanisms and methods put in place to help reduce the risk of rivers flooding into residential or business ares.
As part of the Love Your River Cole (LYRiC) project, work will involve creating flood defence mechanisms to help protect areas from the detrimental effects of flooding. Examples of methods used to reduce flooding risks are de-paving, the creation of rainwater gardens and creating floodplains. Keep reading for more information on each type…
De-paving involves reducing the areas of unnecessary pavement and replacing them with permeable materials, such as gravel or soil. This enhances the absorbency of the ground, meaning when high levels of rainfall are experienced, a lot of the excess water is soaked up by the soil instead of running off into the river. Therefore, the amount of water in the river is less likely to reach flooding heights. De-paving also benefits the environment by creating more green spaces in which plants and trees can grow.
Rainwater gardens are also called bioretention facilities. They are areas of garden designed to catch and absorb the water running off from roofs of buildings, typically planted with species which can tolerate water-logging for extended periods of time. Rainwater gardens are easy to manage because they don’t need watering once they are established, and they can make attractive features within a typical garden. Planting a wider variety of plant species within a rainwater garden is also beneficial in attracting a diverse range of insects and small animals, which is beneficial to the health of the biological community.
Floodplains are areas of land which are allowed to flood naturally, in order to prevent the risk of residential and business areas flooding in case of heavy rain.
They are typically flat, empty areas of land next to a river and should lie at the same height as the river. Sometimes, farmers may let parts of their farming land flood to act as a floodplain at certain times of year. By reconnecting the River Cole to natural floodplains, the risk of damage to other areas by flooding will be mitigated.
Tame Valley Wetlands have been working with local corporate and volunteer groups to improve the grasslands around the River Cole.
This picture shows staff from Birmingham Airport hard at work on a Wild Work Day with TVW.
The work will contribute towards creating better quality habitats for other wildlife, and enhancing the plant biodiversity around the river. Additionally, ongoing management of the trees and grasses around the footpaths will ensure that public access is maintained throughout the year.
An important part of our work on the River Cole is to tackle the invasive plant species growing along the river banks, particularly Himalayan Balsam.
Himalayan balsam (Impatiens glandulifera) may look quite attractive initially, but it is in fact a non-native invasive species (NNIS) causing a major weed problem, especially affecting rivers, floodplains, connected ditches and waterbodies.
The plant disperses its seeds very widely and very efficiently, with each plant producing up to 2500 seeds that are released and catapulted to distances of up to seven metres! The seeds are then widely spread through rivers and floodings, meaning the plants eventually colonise and take over entire river banks and connected wetlands.
Because Himalayan balsam grows extremely rapidly, it out-competes the native plant species growing nearby. This is problematic: if other plant species are not able to survive, the biodiversity of the environment decreases immensely. It is important for a natural ecosystem to have a high level of biodiversity with many different species so that it is stable and more resilient.
The plant grows especially quickly on riverbanks, and the River Blythe is no exception. Part of our work involves using biological and mechanical control methods to clear the area of balsam so that other plant species are able to thrive and bring back the river’s biodiverse and healthy ecosystem environment. Click on the links below to read updates about our control mechanisms.