White Cart Water Flood Prevention Scheme

Contract 2 - environment

Protecting the wildlife of the White Cart Water - Issue 1

The White Cart Water, a tributary of the River Clyde, is an important wildlife corridor for many plants and animals, including otters, foxes, dippers, goosander and kingfishers along its length and salmon which are found downstream of Pollok weir. The rich vegetation covering the banks of the river provides cover and habitat for many species of bird and mammal. The river provides a refuge from predators and food for the different species which use it. The nature of the habitat provides a natural corridor through the urban landscape along which wild animals can travel largely unseen by the human population living and working so close nearby.

The White Cart Flood Prevention Scheme is a project which aims to provide relief and protection to homes and businesses from the frequent flood events that have in the past caused economic loss and misery. Although by necessity involving disruption to life on the river, the scheme incorporates plans to protect the natural habitat and wildlife of the river.

Figure 1 - The White Cart Water - an urban wildlife corridor

Before works were allowed to start along the river, numerous ecological surveys were conducted for wildlife including for birds, badgers, bats and otters. The results of these surveys demonstrated the rich diversity of wildlife that uses the White Cart including otters which have already been seen by several of the staff working on the White Cart project. A full time Ecological Clerk of Works has been appointed to monitor the protection of the river and its wildlife during these works.

Figure 2 - Surveying for otter along the White Cart

Figure -3 Otter prints in the river mud

In order for work to proceed, a licence to work in the otter habitat was applied for and this was issued by Scottish Government in February 2009. Provisions and conditions within the licence have been laid down to protect the otter such as providing alternative resting places for the otter in the form of artificial dens or holts and following working practices that allow free access along the river by the resident otters. Where works will take place near to a known otter resting place, the resting place has been fenced off to ensure that neither person nor machine moves near to the resting place and to provide some protective barrier for the otters.

Figure 4 – Protective fencing in place

Wherever possible, digging to construct the flood defence walls is carried out avoiding the trees and natural riverbank vegetation. Unfortunately, this is not always possible and in February and March 2009, trees were felled in those work sections where work was due to start and where it was not possible to leave the trees in place. The tree felling was conducted at this time in order to avoid the bird nesting season. In case some birds had started nesting early, however, an ecologist with a tree climber to assist was appointed to check each tree before felling both for nesting birds and for bats which may hibernate in hollow sections of large trees. Further tree felling will be carried out from August 2009 through to March 2010.

Figure 5 – A tree climber checking for bats and nesting birds

In some cases, large trees were section felled especially where they could not be checked from the ground for bats or nesting birds. This means that the trees were felled by cutting small sections or branches at a time using a tree climber or a cherry picker. In this way, each section could be checked at a height and then carefully lowered to the ground for further checks. Using this method also means there is less risk of falling branches damaging the watercourse or surrounding land.

Figure 6 – Section felling of trees in Cathcart

To access the riverbank with large machinery, temporary platforms have been made in the river in certain sections. As silt can damage the aquatic environment for fish, invertebrates and freshwater plants, silt curtains have been erected in these areas to catch the silt that may enter the river from these operations. There has been some unavoidable disturbance of the river bed but the introduction of silt into the watercourse is minimised with the precautionary measures that have been employed.

Figure 7 – A silt curtain in action at Cathcart

Before any works commence, pre-construction ecological surveys have been conducted and are planned throughout the year to check the environment for wildlife that could be impacted upon by the works. This will ensure that any otter resting places, new mammal burrows or bird’s nests that may appear along the river will be found before the workers move in and the appropriate actions taken to protect the animals involved. This has taken the form of closing burrows using a specially designed one-way gate which will allow the animal such as a fox, to leave the burrow safely but will not allow its return. After a period of monitoring, to ensure that no animal is trapped inside, the burrow can then be safely destroyed before work on that section can then start. If a nest or burrow was found to have young, work would be delayed to allow the young to leave the nest.

Figure 8 - One way gates in use near the East Renfrewshire Council buildings.