Watercourse advice note (Aylesbury Vale area)

Buckinghamshire Council (BC) recognises the importance of our watercourses, including rivers and streams, as well as associated corridors with features such as floodplains and ponds. This advice note provides guidance to planners, designers and developers for use with planning applications near to watercourses and their associated corridors in the former Aylesbury Vale area.

The guidance supports section ‘9 Natural Environment’ policies of the adopted Vale of Aylesbury Local Plan 2013-2033 (September 2021) (see Local development plans for more details). These policies state what is expected from all development proposals within the Vale and should be read in conjunction with this document.

This document is an advice note and therefore does not set policy, it has not been adopted as supplementary planning guidance, but it is a material consideration of reference for planning application reports and appeals. The purpose is to provide practical advice to make for a better planning application and understand the issues considered when planning in the context of watercourses.

Early consultation is advised using the Council’s pre-application service and also with the Council’s ecology and flooding/sustainable drainage sections at the time a planning application is submitted (and evidence of this must be provided) to understand the baseline position on ecology assets and water resources.

This advice note is produced by Buckinghamshire Council’s Environment and Strategic Flood Management Teams, working with specialists from Buckinghamshire Council, the Environment Agency, the Freshwater Habitats Trust and the River Thame Conservation Trust.

This document uses the Environment Agency definition of a ‘watercourse’ as the term is not defined in the Vale of Aylesbury Local Plan. Therefore, the definition includes a river, brook, beck, ditch/drain, stream, Leat, Goyale, Rhyne and a culvert.

The Vale of Aylesbury in Buckinghamshire is home to a vast network of streams, many of which flow through our towns and villages and there are many ponds, ditches and springs dotted across the landscape. Several of these fall within areas which are recognised as being important for wildlife on a county or regional scale, and are known as Biodiversity Opportunity Areas.

Several rivers flow through the Vale:

• the River Thame, which begins to the east of the village of Hulcott near Bierton meanders through meadows to the north and west of Aylesbury down to the Thames at Dorchester in Oxfordshire
• the River Ray further to the north, which flows west to the River Cherwell and then into the Thames near Oxford
• the River Ouzel which springs near Dagnall in the south west of the Vale and flows to Leighton Buzzard and Milton Keynes and Newport Pagnell to its junction with the Great Ouse
• the River Great Ouse, which flows east from Syresham in Northamptonshire through Buckingham towards Bedfordshire, Cambridgeshire to the North Sea at The Wash

These watercourses are fed from groundwater and rainfall. The land use in the catchment influences how and when water reaches the watercourse and also influences water quality.

For more information on the distribution of watercourses in Aylesbury Vale please refer to the Aylesbury Vale Main Rivers and Ordinary Watercourses Plan which is provided as an appendix to this advice note.

Watercourses are under significant pressure with only 14% of the United Kingdom’s rivers in good health (source: Environment Agency 2018 The state of the environment: water quality).

Developments can negatively impact our watercourses and associated corridors by:

• polluting discharges and/or contaminated run-off entering the surface water or groundwater environment as a result of construction
• reducing water quality due to contaminated run-off during the construction and/or operation of the proposed development
• degrading the watercourse environment and increasing risk of blockage and flooding as a result of culverting
• increasing the disturbance of natural watercourse habitats by humans and domestic animals
• causing poor watercourse environment management practise, resulting in over shading and or loss of bankside vegetation cover
• changing hydro morphology, quantity and flow of surface waters
• interrupting groundwater flow paths through excavations and/or changes in ground level

Degradation of watercourses, or their partial or complete loss is now common throughout the country (13% of freshwater and wetland species are threatened with extinction from Great Britain) (Hayhow DB et al. (2016) State of Nature 2016. The State of Nature partnership.)

In addition, rising temperatures, and changes in precipitation patterns as a result of climate change could be very harmful to the health of the Vale’s watercourses and the species which rely on them. Protecting and enhancing watercourses and their corridors through development will increase resilience to future climatic changes.

Development has a significant role to play in ensuring further deterioration does not occur and restoring degraded watercourses.

Buckinghamshire Council will ensure all opportunities are taken to protect, restore and enhance watercourses and their associated corridors for the built environment, people and nature.

Opportunities for the built environment include:

• creating attractive places where people want to live, work and play through integration of water and green spaces in the built environment
• cost-effective infrastructure that uses fewer natural resources and has a smaller whole-life carbon footprint
• creation of developments that are more able to cope with changes in climate
• protecting people and property from erosion and increased flood risk from climate change

Opportunities for people include:

• better human health and well-being through leisure and recreation
• areas of natural beauty and places of tranquillity
• access to green space, including cycling and pedestrian routes
• providing society with a valuable supply of water

Opportunities for nature include:

• natural habitat and features which provide a home for wildlife
• increased biodiversity supporting a vast range of rare and protected species
• important wildlife corridors which increase connectivity between natural habitats and allow unrestricted passage to wildlife
• increased resilience to climate change and associated pressures
• areas free from disturbance with clean, pollution free water

Development can positively impact on watercourses and their associated corridors. Careful design of the built environment will greatly improve the value of a development for both people and nature. This document details how this can be achieved.