Chalk-streams are finally getting some attention. Minister Pow recently made a clear statement in the Commons saying how much this government valued our chalk-streams and intended to take their conservation and restoration seriously.
It is very good news also to see that today Charles Walker MP and Oliver Heald MP have launched a new All Party Parliamentary Group of MPs dedicated lobbying on behalf of our chalk-streams.
I hope that our Chalk-Streams First initiative to cease abstraction in the Chilterns will be a key talking point for the MPs. This idea would yield a massive environmental gain at a modest economic cost. That must be an attractive idea for a government looking for ways to honour its intention to do well by our chalk-streams.
The Chalk-Streams First idea underlines that the starting point for any healthy chalk-stream must be water. Water is the stream in chalk-stream. Without it you have nothing: a dry riverbed that weeds over, a relic furrow in the landscape, a ghost. I have taken pictures of such places and know that without a bridge or some now incongruous “no-fishing” sign it is hard to show that a river should be there. And after a while it is easy to forget.
So, our first and most important battle is for water. Most chalk-streams are abstracted and many unsustainably so. That must change.
If nothing else the APPG MPs who care about chalk-streams will do well to focus the government’s attention on to this and force a change. We need new legally binding abstraction limits – not guidelines – to properly protect these rivers and we need to find ways to help water companies to abide by them. Chalk-Streams First is the start because it is the model of how we can all move forward together to a more sustainable future.
These new limits should not be based solely on flow, as they are – very haphazardly – at the moment. Looking at flow alone doesn’t protect the ephemeral winterbourne reaches of chalk rivers and anyway it is subject to such subjective interpretation. What percentage reduction of fully natural is acceptable? What is a fully natural flow at any given point in space and time, anyway?
Flow is so variable and because it is so variable it is impossible to adequately police, or even understand, the reduction that abstraction creates. That’s why we have been arguing about it for fifty years and still argue about it. Because without sophisticated and expensive computer models it is very difficult to say how much less than natural the flow is. For example, there is a UK BAP (Biodiversity Action Plan) target for acceptable flow reduction in chalk-streams – somewhere between 10 and 15%. I wish! No river I have ever looked at in detail has its flow reduced by abstraction by such a small amount. None.
It would be better to set limits to groundwater abstraction as a percentage of the annual re-charge of the aquifer. This is a much simpler idea: it sees the aquifer and catchment as a bank account, whereafter the water credit and debit cycle is child’s play to understand and even to measure.
What goes in is effective rainfall – the rainfall that gets through to the aquifer after lossses to vegetation and evaporation. What goes out flows down the river. Unless it is abstracted instead. In which case it is lost to the river.
All sorts of nuances notwithstanding, it is basically that simple. Not only has an unsustainable amount of water been diverted from rivers to abstraction across all our chalk-streams (it is not uncommon to find that abstraction is the same or greater than river flow) there have been years in the Chilterns when abstraction has even exceeded the re-charge of effective rain! It doesn’t take Einstein to see that if you raid a bank account of more than you put in you will soon be broke. As the chart for the Ver below shows, abstraction in this chalk-stream has historically been well over those UK BAP targets. In the mid 1980s it crept up to 45 Mld, or 56% of the average annual recharge of about 80 Mld. No wonder the river dried up. Even now Ver abstraction is running at about 27 Mld when it should be about 8 Mld.