River Colne Catchment Action Network

Catchment projects

Hover over a numbered spot to see a project summary. Click on a spot to see the full project details. Alternatively view the project list.

The Colne rises from a subterranean river at a spring in North Mymms Park. Tributaries of the Colne include the Mimmshall Brook, Tykes Water, River Ver and Ellen Brook.

15. Recovery and Recycling of Aquatic Plastic

Aim: Involve people with their local waterbodies; Improve wildlife corridors; Work together

Ensure that plastic litter collected from in or near aquatic environments is recycled and that sending to landfill or incineration is avoided. Reap-UK will act as the ‘conduit’ for environmental groups and collect take (by prior arrangement) the dirty and fouled wide ranging plastic (anything goes) that will determine it ending up in landfill or incineration – neither of which is good! There is potential for products manufactured from that plastic to come back to the environment from where it was collected – benches, shelters, owl boxes etc.
Recycling is the time consuming and expensive option – dumping in the ground or burning is the easy, cheap option but either of those options continues to destroy our environment.

There is a recycling hub/collection point in Tolpits Lane, Watford. Reap-UK is registered charity number 1201470.

The picture shows ReAP-UK & ColneCAN working in partnership on 12th September 24 with the EA on litter clearance on the Colne Brook near Wraysbury - part of the Colne Catchment. The fouled, low quality plastic, normally destined for landfill or incineration can be transformed into products such as the owl box in the photo.

14. Karst tracer testing project

Aims: Improve water quality

Aim: Better understand chalk aquifer function and quality

Project description

The University of Leeds, Environment Agency, British Geological Survey and Affinity Water have all co-funded a PhD study into the impact of micro-karstic flow on Chalk aquifer function and water quality.

This research has involved catchment-scale groundwater tracer tests using harmless bacteriophage and dye tracers in the southern chalk aquifer to determine flow paths, travel times and levels of dilution and dispersion from surface karst features such as stream sinks (swallow holes) in the Mimmshall Brook, Essendon and Upper River Colne catchments to chalk groundwater abstractions and springs in the Lea Valley.

The tests have been able to: i) identify vulnerable groundwater abstractions; ii) aid catchment management by identifying high-risk surface karst features and more effectively focus funded measures to protect groundwater abstractions; iii) inform catchment-scale groundwater models; and iv) further delineate the karst network in this region of the southern chalk.

13. Micropollutants Study

Aims: Improve water quality

Project to identify the micropollutants present in surface, groundwater and sediment samples along the River Colne and Ver from Lairage Land upstream to the source of the River Colne.

12. Rediscovering the River Colne

Aim: Control invasive non-native species; Involve people with their local waterbodies; Improve wildlife corridors; Improve water quality; Manage flow; Work together

Rediscovering the River Colne is a ground breaking project that aspires to bring the River Colne to the heart of Watford Town and its people.

11. Farming 4 Clean Water

Aim: Involve people with their local waterbodies; Improve wildlife corridors; Improve water quality; Work together

Affinity Water are working with farmers and landowners in the Mimmshall Brook and Upper River Colne to prevent losses of certain pesticides and sediment loss into water courses.

10. Invasive non-native plant control strategy

Aim: Involve people with their local waterbodies; Work together

Strategy to control or irradicate non-native invasive plant species from the Upper Colne.

9. Watford in the Water

Aim: Control invasive non-native species; Involve people with their local waterbodies; Work together

‘Watford in the Water’ is an ongoing river Colne maintenance and improvement project, sometimes working with work experience students and volunteers.

8. Recording pollution incidents

Aims: Improve water quality

The Colne Valley Fisheries Consultative (CVFC) are leading on a pollution monitoring initiative.

7. Exploration into the removal of three river structures at Riverside Watford.

Aims: Improve water quality

Investigation into the possible removal of three river Colne structures.These comprise two sluice gates and a weir.

A section 106 legal agreement has been signed making the following commitment:

6. Japanese Knotweed Management Plan Watford Borough Council

Aims: Control invasive non-native species

Japanese Knotweed management plan treatment starting in March 2016 on Knutsford Playing Fields, Riverside and other parts of Watford Borough Councils Land

5. Habitat Improvement River Colne Oxhey Park

Aims: Improve water quality

In order for the River Colne at Oxhey Park to better perform as a high quality habitat, a project was proposed to introduce a series of brushwood berms along the South bank and undertake some light maintenance works along the existing berms on the North Bank.

4. Upper Colne Riverfly Monitoring group

Aim: Involve people with their local waterbodies; Improve water quality; Work together

A riverfly group led by the Friends of Oxhey Park currently monitors three sites on the Colne in the Watford area. The group was set up through the Chilterns, Hertfordshire and Middlesex Riverfly Hub and began monitoring in November 2014.

3. Litter Boom at Oxhey Park

Aims: Improve wildlife corridors

The installation of litter boom on the Colne in Oxhey Park to trap rubbish, allowing clearance where the river enters the park.

2. Mimmshall Brook "Zero Metaldehyde" project

Aims: Improve water quality

Working with farmers in the Mimmshall Brook to reduce metaldehyde (pesticide in slug pellets) pollution impacting the river and drinking water abstraction

1. Improvements to access and wetlands at the Withey Beds

Aims: Involve people with their local waterbodies

A project to carry out some improvement works at the Withey Beds Local Nature Reserve, to include ditch management, creation of ponds and scrapes, provision of improved site interpretation, and extension of a board walk to provide access to the bird hide.