It rained all day yesterday - really heavy rain that settled on the garden in big puddles and is still there this morning. Many roads were flooded creating a strain on our antiquated drains.

Woke up this morning to find it was still raining - as I look out of the window there are sheets of water being blown across the garden.

The extremely heavy rainfall over the past few days in SE England co-incided with the arrival of my water rates bill. A timely reminder of how relevant rainwater harvesting is for the UK as we experience far wetter winters as a result of climate change. Read these interesting articles by the UK Rainwater Harvesting Association which explains more about this subject http://www.ukrha.org/articles/7

My new blog launching in January will contain reguar information and suggestions for getting involved with this ancient method of using the free water that falls from the skies. This will be provided by a contact called Marcus Fox from the aptly named Freerain who specialiise in designing, supplying and fitting a range of rainwater harvesting systems http://www.freerain.co.uk/

Marcus is definitely a rainwater harvesting guru and is going to be in keeping me up to date with rainwater harvesting news in 2009. For now, he has provided this introduction to inspire anyone bogged under by puddles at work or at home to seriously consider the value of a domestic or business rainwater harvesting system. The initial costs may seem high but, the pay-back will last forever  - extreme winter rainfall is here to stay!

Marcus writes his own blog which has excellent practical and technical advice:

http://rainwater-harvesting-systems.blogspot.com

Or ‘wet’ your appetite with:

Rainwater harvesting is not a new practice, but since the introduction of
clean and reliable water supply during the Victorian period the practice of
collection your own water fell out of practice.
In Germany rainwater harvesting is much more common and they as a country
have been leading since the 1970s. In the UK a few companies including
Freerain Ltd have been supplying a range of systems and together these
companies formed the UK rainwater harvesting association. One of the
associations aims is introduce standards in to the industry. A new British
Standard is due to be released in the next few months which should help to
reduce the number of poorly designed and in some cases illegal systems.
A well designed rainwater harvesting system should always include a filter,
either on the downpipe(s) or an underground inline filter. This prevents
too much organic matter entering the storage tanks and protects the pump
and/or blocking of hoses and spray heads. For storage volumes larger than
about 1000 litres, the system really should be underground, this is in part
due to the aesthetics of having a large tank above ground around the house.
Importantly, an underground storage tank is more expensive to install but
they have several advantages. 1) It’s much easier to get the water in the
tank and through filters using gravity. 2) The water is kept dark and cold,
reducing the rate of algal growth and bacteria.
Other aspects of a system should include a calming inlet which allows the
water to enter storage smoothly and helps to retain oxygen levels and
promote good (aerobic) bacteria.
It is important that a system is sized to overflow a few times a year, this
helps to remove a scum layer from the tank and helps circulate the water. A
tank which is too large is not good, for two reasons. 1) The customer will
be buying capacity they will never fill and secondly, the water quality will
be much lower as the it will be turned around quickly enough.
Performance
A domestic system can supply around 50% of the demand for an average house
and substantially more for other applications such as gardens. This of
course depends on the available collection area (roof), the local rainfall
and the efficiency of the collection system.
We are often asked about how we calculate the system of tank, especially by
gardeners. They are sometimes concerned that we are advising small tanks
compared to their proposed usage. But it actually rains significantly about
every 18 days in the UK and even during hot periods, an hours thunder storm
can replenish the tanks very quickly. It’s important to give adequate
coverage, but it is not worth chasing every single last drop.
Costings (underground)
A domestic system (for WC flushing, washing machines & outside tap use, with
mains back-up) you will need to spend around £2000-2700 + VAT supplied
A garden system for garden use only, from about £1400 + VAT, supplied.
Installation costs vary and really a domestic system should be considered by
new-build projects or complete refurbishments. This is because it is
necessary to amend both drainage and internal plumbing and if this is in an
existing house, then this will prove costly. For a planned new-build, I
would budget around £800 for the installation.

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