Water cycle studies are key to enabling a healthy relationship between future growth and the water environment.

Housing demand continues to outstrip supply in the UK; future development is inevitable. It is essential that local planning authorities plan for sustainable growth.

Climate change also has the potential to affect the demand for water and its availability.

Water cycle studies help identify joined-up and cost-effective responses to the pressures of development on the water environment. Responses and solutions that are resilient to both future growth and a changing climate.

Water cycle studies explained

The latest water and planning evidence is used to better understand both local water resources, or availability, and water quality.

Water resources

The key focus here is the relationship between future supply and demand.

  • Supply calculations are typically based on water resource management plans and other data produced by water companies.
  • Demand is based on population growth statistics and local development plans.

By weighing up supply and demand, we can confirm whether there will be sufficient local water resources to meet future demand. If not, the study results provide an early warning to key stakeholders, allowing necessary upgrades to be completed in time or prompting the scaling back of development plans.

Water quality

The key areas of concern here are infrastructural capacity and environmental capacity.

Infrastructural capacity is the ability of the local wastewater system to collect, transfer and treat wastewater from homes and businesses.

Calculations are based on water company guidance on the capacity of their sewerage networks and reviews of the capacity of their sewerage treatment works. These capacities are assessed in the context of projected growth, providing a prompt for any modifications needed to meet water quality objectives.

Environmental capacity is the water quality needed to protect the aquatic environment.

Calculations are based on the storm discharge permits required to achieve local water quality targets, driven by the Water Framework Directive classifications of the ecological and chemical status of watercourses across the UK.

Where a classification indicates existing pressures on a watercourse, the study highlights the work needed to evaluate existing storm discharge permits. This safeguards against further deterioration and, where possible, restores natural conditions.

Our work

When undertaking a water cycle study, we recommend early liaison with stakeholders to confirm what data are available, and a holistic approach to weigh up development needs and existing and future environmental pressures.

In 2018 we completed a water cycle study for Oxford City Council, to support their 2036 local plan.

Oxford is important nationally and internationally, with one of the most important concentrations of high-value businesses in Europe. However, the city’s continuing housing crisis, with lack of housing availability, choice and affordability, is a significant challenge for future development.

An urgent response is needed to manage future development and allocate potential sites for development. Our water cycle study is one part of this response.

We used data from Oxford City Council, Thames Water and the Environment Agency.

Our calculations of demand were based on two different development scenarios suggested by the council:

  • 8,000 homes by 2036, a realistic scenario based on development constraints
  • 12,000 homes by 2036, a notional higher growth scenario.

We assessed the infrastructural and environmental implications of both these scenarios.

Our study provided an overview of the existing pressures in Oxford City and the necessary steps required to ensure that development can take place without compromising the health of the local environment.

The last word

The continued shortfall in housing supply and the potential impacts of climate change on water resources mean that water cycle studies are likely to become more important.

  • They gather information from key stakeholders and highlight potential issues early on.
  • They identify local infrastructural and environmental constraints to development.
  • They enable cost-effective solutions and sustainable growth.