Internal Drainage Boards and the Middle Level Commissioners are traditionally known for their land drainage role and indeed the legislation we operate under is geared towards evacuating water to sea as quickly as possible in order to provide flood protection to communities and land.
However, water is a scarce and valuable resource, particularly here in East Anglia as the driest area of the country. The changing climate is accelerating water scarcity and increasing its value.
Here at the Middle Level Commissioners, we operate a critical water resources service that not many people know about.
The Middle Level of the Fens is essentially a bowl and also a closed catchment, so in the summer this creates water resource and water level management challenges. Historically, the original course of the River Nene went through the Middle Level and the Commissioners rights to take the inflows that were originally directed to their system was preserved by section 59 of the Middle Level Act 1848.
Every year we are involved in twice weekly calls during the main abstraction season with the Environment Agency, Anglian Water and other Lower Nene users to agree on River Nene abstraction.
We then transfer water flows that are available to us from the River Nene via manual operation of Stanground Lock. This enables water levels to be maintained through the summer for the environment, irrigation and navigation. In hot summers, without this water transfer, the system would virtually dry out.
Once water is transferred via Stanground Lock, it flows along Kings Dyke and is then diverted via a structure at Horsey Toll into the Facet Nene/Pig Water. This operation is resource intensive as there are a number of pinch-points that impact water flow and the amount of weed that grows at fast pace in summer. The Pig Water feeds Yaxley Lode at the head of the district’s Bevills pond.
The Bevills Pond
The Bevills pond refers to the drainage district upstream of the Commissioners’ Bevill’s Leam Pumping Station. The Commissioners’ watercourses hold water levels at a higher level that surrounding land levels, influencing the water tables within surrounding land. Within the pond there are circa 25 IDB slackers that seven Internal Drainage Boards can operate to then take water from the Commissioners’ watercourses into their districts when sufficient water flows are available. Local farmers then use this water to irrigate their crops and environmental land managers use the water to sustain and improve biodiversity and also manage water levels to sequester carbon.
“Lowland peatlands drained for agricultural use are fast degrading. When peatlands degrade, their soil is lost, the land subsides and the carbon they preserve is released primarily as carbon dioxide to the atmosphere. This process is bad both for farmers and for the climate. Greenhouse gas emissions in England released by lowland agricultural peatlands were estimated to be around 6.5 million tonnes of carbon dioxide equivalents in 2021; this equates to around 1.5% of UK total emissions.”
The Bevills pond contains some of the deepest peat soils in the country. Holme Fen and Woodwalton Fen nature reserves are nationally important wetland sites that are within the Great Fen Project that is restoring and re-wetting many hectares of degraded peatland in this area. The Great Fen Project, of which we are a project partner, will trailblaze a model of agricultural production, which aims to inspire and change farming practice on peat soils across the UK.
Without ‘importing’ water from the River Nene through the summer periods it is likely that there will be insufficient water within the pond to enable any transformational landscape change needed to better manage peat soil water levels, sequestering damaging carbon dioxide emissions.
St Germans Pond
In addition to water being diverted into the Bevills pond, water transferred from the River Nene helps sustain water levels in the summer within the St Germans pond. This larger area is a network of drains with water levels maintained at a higher level than in the Bevills pond.
Maintaining a water level in the St Germans pond is crucial for navigation and in particular the link route connecting the River Nene and River Great Ouse. Without our management of levels and the transfer service Cambridge would not have a navigation connection with the national canal network, without boaters braving The Wash and changeable tidal conditions.
There are over 60 IDB slackers in this pond that enable water when its available to be further transferred into IDB systems for irrigators to use.
Currently water within the Middle Level is not used for public water supply. However, Anglian Water and Cambridge Water are developing the Fens Reservoir to address serious deficiencies in water supply. The proposed site is within the St Germans pond and we are working closely with Anglian Water and are part of the Fens Water Partnership led by Water Resources East.
If approved, the proposed reservoir will be the next great water engineering scheme within the Fens where ambitious, innovative and controversial landscape scale change has been a feature since the great drainage started in the 1600s. The reservoir and its associated system could arguably be the most transformative change in water management that balances and supports a wide variety of interests, public good and private sector aspirations, helping us collectively to address the climate and nature crisis. It is more than just a once in a generation opportunity.
We also have involvement in a smaller scale operation at Old Bedford Sluice which is an Environment Agency asset next to our lock at Salters Lode. In summer, when tide and salinity levels allow, the sluice is operated to transfer water from the Gt Ouse Tidal River into the Old Bedford River.
Upwell Internal Drainage Board, Manea & Welney Drainage Commissioners and Sutton & Mepal IDB then operate slackers to transfer water into their systems for local farmers and to sustain the environmental value within their drains, including the Old Croft River which has heritage value as an original fenland watercourse.
A hidden critical service
We have no direct legal duty to provide this wide-ranging water resource service, however without it; farmers would not be able to irrigate their crops in summer proving local food for UK consumers; the local natural environment would be irreparably damaged; our rivers would not be navigable and our flood banks would be destabilised increasing flood risk to surrounding communities.
We hope that government will change legislation and funding arrangements to truly recognise, value and reward the role the Middle Level Commissioners and Internal Drainage Boards play in conserving, transferring and sensitively managing water.
of main arterial channels and navigation managed and controlled within the Cambridgeshire fens