This presentation formed part of the Farming Futures event 'FarmWater Futures'. 30th March 2010

1. Rainwater Harvesting on
Farms
Phil Metcalfe
ADAS UK Ltd
www.adas.co.uk

2. Presentation overview
Agriculture water use
Benefits of RWH in agriculture
Considerations
Water quality
RWH in varying agriculture sectors – case
studies
Legislation

3. Acknowledgements
The Environment Agency Midlands and
Anglian Region.
Case Study farmers and growers
Report and Booklet
Rainwater Harvesting Information for
Agricultural Customers

4. Is there a need for RWH in agriculture?
Total water use by agriculture in England and Wales is of the
order of 300 Mm3 (Irrigation – 131 Mm3, Livestock – 158 Mm3;
Protected crops – 20 Mm3).
Total water use is less than 1% of total abstracted for the
public supply, power generation and industry.
Low return, geographic and seasonal focus results in
significant impact:
Spray Irrigation @ 25 mm per week
×
1% of Land in Potatoes and Vegetables
≈
25 to 50% of River Low Flow in Eastern England
*Key Data Sources: Defra Survey of Irrigation of Outdoor Crops
EA National Abstraction Licensing Database (NALD)
Baseline Data on Water Use in Agriculture (Defra Project WU0102)

5. Benefits of RWH to agriculture
Reduction in mains water supply costs
Reduction in sewerage costs
Reduction in the amount of water entering a
slurry store
No treatment additives, such as chlorine and
therefore better for irrigation
Avoided site drainage and flood risk
Reduce dependence on supply from rivers and
ground water

6. Factors to consider before installing a
RWH system
Is there enough rainfall?
Can it be stored easily?
What quality of water is needed?
What is the capital cost?
What are the running costs?
Is there an economical benefit?

7. Water quality
Water Use Quality Required Treatment Options
Plant nurseries Water is not used for First flush diverted
Field irrigation consumption, very low Coarse filter
Buildings, machinery risk of contact. Water Sand filter
and yard cleaning should look clean and be
odour free
Toilet flushing
Filter backwashing
Process or equipment Water is not used for All of above
cleaning consumption, very low Fine filter
Sprayer wash out risk of contact. Water
should look clean and be
odour free, but not
necessarily sterile
Food cleaning and Water maybe used for All of the above
processing consumption, water must Pathogen removal
Irrigation of ready to eat be clean, odour and and/or inactivation
crops pathogen free (e.g. UV treatment)

8. Water quality for crop irrigation
Recommended standards set
out by WHO
Food retailers and food
assurance schemes will have
additional requirements
More rigorous than WHO
recommendations
Horticulture crop production
quality and hygiene
Not suitable for over head
irrigation systems

9. Water quality for animal drinking
Hygiene and farm assurance
scheme requirements
Water for hand, udder or dairy
plant washing must be from a
potable source
Water for animal drinking needs
to be ‘fresh and clean’
Disease control in intensive pig
and poultry industry

10. Livestock sector
Farmers pay £31 – £100 per
cow per year for water
20% of this water could be
met with rainwater for:
Livestock drinking
Feed preparation
Pen cleaning
Slurry management
Vehicle washing

11. Livestock case study - Wrexham
96 ha Collected from 2 roofs – 1431 m2
70 milking cows, 70 2 storage tanks – 4.46 m3
followers, 100 ewes Cost = £300
Grows maize and barley for Saving per year = £479
animal feed Pay back time is 1 year
Harvested water used for
drinking water for cattle

12. Arable sector
Large areas of roof
Harvested water can be
used for:
Irrigation
Vegetable washings
Machinery washing
Crop spraying and
sprayer wash down
Yard washing
Dust suppression
Filtration may be required

13. Arable case study - Lincolnshire
400 ha Collected from 2 roofs
Arable crops and specialist 2 storage tanks, 1 for sprayer
crops e.g. fennel, artichoke and 1 for cold store
and celeriac Very low cost – parts and labour
Harvested water used for Saving per year = £310
crop spraying and for Pay back time is 1 year
misters in cold store

14. Protected cropping sector
Rainwater can be used for
irrigation, hydroponic systems,
machine washing and crop
spraying
Filtration is generally required
Crop product quality and hygiene
is important
Suitable for root zone watering
but not overhead irrigation
systems on edible salads or fruits
Reduces problems with drainage,
humidity, soil erosion and
improves plant health

15. Polytunnel case study - Herefordshire
120 ha of tunnels Collected from 12 ha of roof drains
Grows raspberries, Drains connected to a natural
cherries, strawberries, reservoir
blackberries and Water is pumped to irrigation
blueberries house and through sand filters
Harvested water used in Harvests 5,852 m3 per year
automated irrigation Pay back time is 3 years

16. Glass house case study – East Yorkshire
40,000 m2 glasshouses Gravity collected from a proportion
Grows cucumbers, of glasshouses
aubergines and Pumped to a purpose built reservoir
peppers and then through a filter into 40,000l
Harvested water used stores
for hydroponic plant Harvests 8,500 m3 per year
feeding Invested £16,000 repaid in 2 years

17. Legislation specific to agriculture
Environmental Permitting
The Food Hygiene Regulations
Welfare of Farmed Animals Regulation
Water Impoundment and Abstraction
Nitrates Directive

18. Conclusions
Initial outlay and factors such as water
quality standards may put famers off
Capital cost ranges from £300 - £750,000
Payback ranges from 1 year – 6 years
Savings range from £160 - £120,000 per
year
Funding is available
As well as economic and environmental
factors there are also pressures from
water companies and food retailers to
utilise rainwater harvesting
Agriculture is able to make savings with
RWH if the system is appropriate to the
farm size and type

19. Thank you
Phil Metcalfe ADAS UK Ltd
tel. 01902 693224
phil.metcalfe@adas.co.uk
www.aplus.adas.co.uk
www.adas.co.uk