The water feasibility project investigated the requirements for water for two example products – bread and tomato paste.
A comparison was made between the current global situation and a more localised ‘what if’ situation. The localised situation was applied to two case studies in Oxford (a medium-sized, established city where space is at a premium) and Northstowe, Cambridgeshire (a new town currently under development and construction).
The project considered the differences in water use of a change from the current global situation to production at a more local scale linked to the amount consumed in Oxford or Northstowe.
The implications for land use changes for growing the crop, the technology needed to manufacture the product and the food-energy-water nexus issues are discussed. Finally the opportunities for water saving measures were assessed.
The final report for the Water feasibility project is available.
The Executive Summary and Key Research Questions are provided:
This report presents a detailed description of a water feasibility deliverable which is one of the mini projects of the Local Nexus Network (LNN). The purpose of this deliverable is to identify the potentials, bottlenecks and constraints of the water sector for local food production at regional or city levels. The report is divided into the following sections. In the first section, a literature review is presented related to food-energy-water with a particular focus on water aspects. This section also includes review of water sources, water demand estimations and water footprint concepts and their implications and impacts on the food-energy-water nexus. The next section outlines the key features of the case studies in this project (i.e. Oxfordshire and Northstowe). These key features can be used to identify the potentials of water resources and demands to develop local food production and manufacturing in the case studies. Water availability and land use required for cultivation and processing are also evaluated in both case studies.
The main focus of the project was on two types of food manufacturing/processing: bread and tomato paste. Hence, their local production demand and required water quality have been investigated along with potentials for water saving and improving efficiency.
Analyses of the water footprint and demand at different steps of tomato cultivation and processing identified some potential for water conservation and energy efficiency measures for tomato paste. These could result in economic benefits from reduced energy costs and significant environmental benefits from the preservation of groundwater resources and reduced wastewater discharge. Currently, all tomato paste consumed in the UK is imported from other countries. This report also explores the water, energy and carbon implications of this and compares it with a scenario where demand would be locally met. Results indicate that the water footprint is considerably smaller for the local production case as compared with imported tomato paste. However, the energy and carbon footprints of tomato cultivation are quite large in local heated greenhouses, although this is partially offset by the energy savings resulting from reduced transportation.
Finally, details of water used in local bread production are presented. The water footprint of wheat-based production of bread is analysed at different scales in the UK and compared with values in the rest of the world. Water used in bread manufacturing is analysed in milling and bread making processes. Other aspects of water in bread manufacturing including water quality, environmental impacts and water- energy nexus are also discussed. The potential and opportunities for water efficiency in localised bread manufacturing along with its impact on energy footprint and other environmental categories are identified and discussed.
Key research questions:
- What is the optimum level of water supply from different water sources (e.g. groundwater, rainwater, stormwater, grey water, black water, yellow water) for local food production considering economic, social and environmental factors?
- What innovative technologies are needed to improve efficiency in providing alternative sources of supply?
- What is the best match for water quality between demands and supplies?
- What type of water treatment is required and at what cost?