Project highlights

  • Exciting opportunity to work with the UK’s largest gardening charity and its 620,000+ members
  • Apply a combination of measurement, modelling and remote sensing approaches to quantify water balances within UK domestic gardens
  • Inform Royal Horticultural Society gardening information and advice, as well as future campaigns to improve water resilience in UK gardens.


There are around 30,000,000 gardeners in the UK whose combined area of private outdoor spaces has been estimated at over 4,300km2 or around 20% of the area of Wales.  Gardens and other domestic outdoor spaces therefore represent a major natural resource that is under highly diverse management and whose contributions to groundwater recharge, storm runoff and mains water use is highly uncertain and under-valued – leading to the loss of garden area due to paving or housebuilding.  Furthermore, garden water use is strongly seasonal with high demands typically during periods of low supply. Research in this field has the potential to contribute towards alleviating current (seasonal) water stresses experienced by the water sector, while maintaining expected levels of quality in gardens. This exciting PhD, in collaboration with the Royal Horticultural Society, will aim to use a combination of data analysis, monitoring and modelling to develop an improved understanding of the water balance of domestic gardens and evaluate how the ‘green infrastructure’ benefits of gardens can be improved to increase society’s resilience to floods and droughts.

The PhD has the following outline objectives:

  1. To design, install and monitor site-based measurements of the components of garden water balances;
  2. To parameterise, calibrate and validate an appropriate numerical model to simulate the hydrological behaviour of gardens;
  3. To combine data analysis, modelling and remote sensing approaches with land-use classification information to develop an up-scaled spatial analysis of the contribution of UK domestic gardens to the nation’s water balance;
  4. To provide recommendations on how domestic gardeners can manage rainwater in their gardens to optimise rainwater storage and resilience to floods and droughts.

photo of a garden with vegetable beds, fruit trees and a greenhouse

Figure: Gardens are highly diverse, making understanding their water balance (how water enters, leaves and is stored in gardens) an important challenge

Case funding

This project is suitable for CASE funding


Cranfield University


  • Climate and Environmental Sustainability


Project investigator

Prof. Ian Holman, Cranfield University ([email protected])


Dr Mark Gush, Royal Horticultural Society ([email protected])

How to apply


Three main approaches are expected to be adopted during the research:

  • Monitoring – Design and installation of appropriate experiments to quantify water balances and dynamics in different vegetation types within domestic gardens (e.g. lawns, plants and trees), potentially including weather monitoring, plant cover, sap flow, soil water release characteristics and soil moisture variation
  • Modelling – daily soil water balance modelling of monitored locations, evaluated against observations and comparison of variability in longer-term modelled behaviour against remotely sensed Vegetation Indices. Model application to explore the effects of changing gardening practice.
  • Upscaling- application of remote sensing datasets to urban garden green space to characterise different vegetation categories (e.g. lawns, plants and trees) and areas. Integration of the RS area assessments, other spatial datasets and the soil water balance model to quantify the contribution of UK domestic gardens to the nation’s water balance.

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

This PhD will suit a student with a hydrology, physical geography, environmental science or similar background, given the monitoring and modelling components.  However, depending on the student’s background, training will be available at Cranfield University in understanding soils, modelling, GIS and remote sensing.  This will be augmented, as required, by bespoke training in soil and vegetation monitoring by the RHS Environmental Horticulture team.

Partners and collaboration

The Royal Horticultural Society (CASE partner) is the UK’s leading gardening charity.  Their charitable purpose is to inspire passion and excellence in the science, art and practice of horticulture and to be the leading global gardening charity, demonstrating excellence in horticulture and promoting gardening. We provide advice, knowledge and services to our 620,000+ members; 2.9 million visitors to our gardens; and 547,000 visitors to RHS Shows. We also engage with 34,000 schools, 300,000 RHS Britain in Bloom volunteers and the wider horticulture industry. Our online information attracts approximately 30 million ‘hits’ from amateur and professional gardeners each year.

Further details

If you wish to apply to the project, applications should include:

  • A CV with the names of at least two referees (preferably three and who can comment on your academic abilities)

Applications to be received by the end of the day on Wednesday 11th January 2023. 

Possible timeline

Year 1

Literature review on the hydrological cycle of gardens; drafting manuscript; refine and agree research design; monitoring installation.

Year 2

Site monitoring; model parameterisation, calibration and validation; drafting manuscript.

Year 3

Completion of monitoring and modelling; upscaling assessment; analysis and writing-up.

Further reading


Most aspects of the proposed project are resilient to any respiratory and contact infection pandemic as the major activities are either outdoors (garden monitoring) or desk-based (data analysis, modelling, remote sensing).  Laboratory activities for soil analysis (e.g. pore size distribution, soil water release) are not time-critical so mitigation will include re-scheduling or substitution with pre-existing pedotransfer functions.