A national grid for water resources AND saving chalk streams – let’s deliver that!

Our new Prime Minister mentioned chalk streams at a hustings in Cheltenham earlier in the summer and in yesterday’s Daily Telegraph she cited a problematic lack of investment (which she aims to change) in large infrastructure projects such as reservoirs.

All this is good news, suggesting the new look government will take seriously the protection of our precious chalk streams and not make the mistake – as has often been made in the past – of regarding economic growth and ecological protection as mutually exclusive. Chalk streams have been waiting a long time for the protection and investment which is due if we are not to continue as dreadful hypocrites, unable to look after the natural wonders on our doorsteps.

Yes indeed, we need reservoirs: in the Fens and Lincolnshire, in Kent, Hampshire and the Thames basin, reservoirs would facilitate schemes which could protect public supply and ease the burden of over-abstraction – and this year must surely have shown what a burden it is. But it is worth remembering how long it takes to navigate the inevitable public enquiries that surround reservoir schemes, let alone build them. If we rely on reservoirs alone, we will be waiting a while. I photographed the bone-dry River Beane (above) in 2007, 2017 and now again in 2022 and I’m not sure how many more times I want to do that.

To deliver an effective, simple scheme guaranteed to build resilience of supply and to facilitate the ecological restoration of our precious chalk streams, our new Prime Minister, the new-look government and the new environment minister should (as well as lighting the touch paper on longer-term planning) urgently catalyse a more timely suite of schemes along the lines of a national grid for water resources. Below is a short paper which I hope may have found its way to a desk at Defra. If not, I post it here, just in case …

A national grid for water resources.

The restoration of chalk streams around London should be the ecological flagship at the heart of a more fundamental reform of water resource infrastructure in England and Wales and the creation of a ‘national grid’ for water supply which imposes inter-regional transfers onto our currently siloed and fragile supply network.

The south east of England has a high (and growing) population and a comparative shortage of water, especially in drought years. 

The south east is currently dependent on reservoirs filled from the River Thames and groundwater abstraction from storage in natural aquifers. 

However, the Thames reservoirs cannot be reliably refilled in dry winters. This runs counter to the mistaken popular perception that we only need to build more storage: there is already more storage than supply in the south-east during the problematic 18-month droughts, which include dry winters.

Groundwater aquifers, on the other hand, are already over-developed and the degree to which they are exploited causes significant ecological damage, particularly to chalk-streams, many of which are currently dry or very low (August 2022).

Fundamentally, the South East of England needs “new water” because not enough falls from the sky relative to the number of people and the needs of an already damaged environment.

By far the quickest way to achieve this is through inter-regional transfers from wetter and less populated parts of the country. For example, average annual rainfall per capita in the south-east of England is a fifth of that in Wales (assuming SE England = 19096 km2 / 800mm ave rainfall / 9.2 million people and Wales = 20779km2 / 1500mm ave rainfall / 3.2 million people).

The potential of inter-regional transfers (to supply water to the south east from Lake Bala in Wales) was first proposed by a Hertfordshire miller, John Evans, in the 1870s. It resurfaces as an idea every time there is a severe drought and then gets forgotten again till the next time.

More recently, however, the need for inter-regional transfers was firmly identified in the 2016 Water UK report: ’Water Resources Long-term Planning Framework’.

The role of inter-regional transfers is now a key component of the emerging National Framework for water resources and specifically WRSE’s draft plan which proposes that inter-regional transfers are used to move water from the wetter west to the dryer south east, including options such as Severn to Thames Transfer, repurposing the Grand Union Canal to transfer recycled water from the River Trent to the South East as well as potential options for transfers from the west country. 

However, the National Framework timetable proposes that water demand management (water efficiency and drought measures) and leakage reduction will close the largest part of the supply demand imbalance through to 2050. 

Shrinking demand through water efficiency is a vital measure, but offers uncertain results, while the already existing shortage of naturally available water in the Thames valley (as evidenced by the current drought) will become more pronounced if demand grows or if demand management proves a hard nut to crack.

Delaying the use of inter-regional transfers until after 2050 also delays the restoration of flows to the chalk streams which depend on over-exploited aquifers (and thus risks more and more headlines about dry rivers).

Severn to Thames Transfer

A transfer of water from the River Severn to the River Thames could yield in the order of 100 Ml/d, (in itself enough to restore close-to-natural flows to all the Chilterns and Hertfordshire chalk streams) requires zero inter-company trading and is deliverable in the short term.

With support from Vyrnwy, the Severn-Thames transfer could provide up to 500 Ml/d of yield for Thames Water and other water companies in the South East. 

The draft WRSE regional plan indicates that the Severn to Thames transfer could potentially be implemented by 2033.

Minworth and the Grand Union Canal

A complementary option that amounts to the same principle of moving water from Wales to the south east involves the recycling of highly-treated effluent from Birmingham’s Minworth water recycling centre, transferred to the WRSE region via the Grand Union Canal. 

The Minworth GUC transfer has a potential yield of at least 100 Ml/d (potentially higher given the dry flow from Minworth is 420 Ml/d) via the Ground Union Canal.

The draft WRSE regional plan indicates that the Minworth GUC transfer could potentially be implemented by 2035.

Both of these options bring new water into the south east region and would allow ALL of the abstraction reductions needed to restore naturalised flow to the iconic chalk streams of the Chilterns and Hertfordshire.

Chalk Streams First

These abstraction reductions in themselves also – counter intuitively – offer water resources options because they do not involve a total net loss to supply. A drastic reduction of groundwater abstraction in the chalk hills would allow groundwater levels and thus river flows to recover: in the Chalk Stream First scheme the aquifer remains a “reservoir of water” while the means of delivery becomes the chalk stream itself, with water taken for lower down the system after the natural eco-system has benefitted. Hence chalk streams first

The flow recovery brought about by abstraction reduction is another strategic resource option amounting to approx 80% of the abstraction reduction averaged across the full year (flow recovery is lower in summer than winter, ranging between 30% and over 100%), using the London reservoirs as storage, and the Supply 2040 pipe network to return water to those places formerly supplied by groundwater abstraction.

Chalk Streams First +

Moreover if the problematic groundwater abstractions in the chalk tributaries are wholly or partly replaced with groundwater abstractions in the lower valley (an idea added to the proposal by Affinity Water) where they will have a much lower ecological impact, then there is no net loss to supply and ALL of the surface water flow recovery becomes available as “new water” in the same category as the STT and GUC water. This could yield up to 80 Ml/d averaged through the year. 

Chalk Streams First offers the opportunity to put a flagship ecological restoration of England’s iconic chalk streams at the heart of the development of a national grid for water, and inter-regional water supply infrastructure which would, for the first time in history, move water from the wetter west and Wales, to the overstretched and dry London and the south east.

Let’s deliver that!

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