As Anglian Water propose creating two new reservoirs (Lincs and Cambs), we accept that there is a clear case for considerable new water supplies in Cambridgeshire, one of the most water-stressed counties in the country. More water is needed to cope with projected population increases, but it is also crucial to address current problems for wildlife. Current levels of groundwater abstraction were one of the key factors identified as affecting our internationally important chalk streams in a report that we produced with the Wild Trout Trust in 2020.

We have first-hand experience of this at our Fulbourn Fen nature reserve east of Cambridge, where the local springs rarely flow and would run dry most summers if the Environment Agency didn’t provide augmented groundwater pumping to keep the fen wet. However, this is often not enough to also keep the reserve wet, leading to a number of summers recently where the fen and wet woodland dried out. This situation is exacerbated by groundwater abstraction for public water supply in the area which depletes the aquifer. 

Is the proposed location the right one?

Deciding on the “right” location for any large new infrastructure is obviously a complicated decision, and while wildlife considerations are important, there are many other factors that the decision makers, in this case the Planning inspectorate, will need to take into account. The Wildlife Trust will object to proposals that have major impacts for wildlife, but that’s not the case with the currently proposed location.

Although there are minor impacts, and could be significant impacts for wildlife if the right safeguards aren’t in place, equally the impacts can be mitigated or compensated for, and there are opportunities for wildlife enhancement that a new reservoir could generate. We have good experience of managing nature reserves at reservoirs, as demonstrated at Grafham Water and Pitsford Water.

Wildlife impacts

Any major construction activity will have impacts on local wildlife. The review of potential locations carried out by Anglian Water looked at the impacts on Local Wildlife Sites (LWS). None are directly affected, but the site proposed includes a small area of floodplain grazing marsh, a nationally important habitat. For housing projects there is a requirement for such impacts to be compensated for with an increase in wildlife rich habitat through a process referred to as Biodiversity Net Gain (BNG), and in our region the leaders of local authorities have called for the required level of BNG to be set at 20% because our LWS are under considerable stress. It’s unclear at the moment whether this requirement will also be in place for larger projects, such as the fenland reservoir proposal. In our view 20% net gain should be a minimum for national projects, and the reservoir proposal provide significant opportunities for habitat enhancements.

Off-site issues are more significant, and the proposed site is adjacent to the Forty Foot Drain LWS, and would connect to the Ouse Washes, an internationally important wetland site for birds. This connection could improve the wildlife of the Ouse Washes if the new reservoir is used to remove water from the Great Ouse in spring floods, which can seriously affect the Ouse Washes, and draw down flood water from the washes themselves.

On the other hand, the Ouse Washes must not be used as an alternative storage area in the event of problems with the reservoir. This could have a major effect on the wildlife of the Ouse Washes, and protections need to be properly guaranteed at the early stages of the proposals.

Other impacts

The construction of a new reservoir is a major project and would cause significant disruption, most obviously for those with homes and businesses directly affected. The construction would be likely to take 10 years, and a new reservoir would be unlikely to be in operation before 2035, more likely 2040. There will be carbon impacts from the construction as well, particularly as the area proposed includes degraded peat. A careful approach will need to be taken to managing the soils to minimise carbon emissions.

Overall, the Wildlife Trust BCN sees the proposed Fens Reservoir as a significant opportunity for nature: we will be working with Anglian Water along with our partners to try and get the best result for wildlife. 

Responding to the consultation

The Wildlife Trust will be responding to the current consultation, which runs until the 21 December 2022.

How can you help? 

We appreciate that local people responding to the consultation will have a range of views about the impacts. It’s important that the wildlife issues are highlighted as important to local people, so that it is properly considered in the development process, wherever the reservoir is finally located. Those responding to the consultation can help if they highlight that:

The proposals must:

• Go hand-in-hand with reduced abstraction from local aquifers and improved leakage management.

• Protect and enhance the Ouse Washes for wildlife

• Minimise carbon emissions

• Maximise the opportunities for wildlife by exceeding local targets for biodiversity compensation, with a minimum of 20% Biodiversity Net Gain

• Provide a long-term local benefit, providing opportunities for people to interact with wildlife on their doorstep