Water neutrality is a hot topic in the development world right now. Dean Knight, our technical director, and Jordan Gresham, regional director for our North region, answer some of your questions.
Dean Knight
Q. Is water neutrality the same as nutrient neutrality?
A. No. nutrient neutrality relates specifically to phosphates and nitrates in protected areas where discharge from affected sewerage treatment works is at a level which exceeds the target levels for protected areas. Whereas, water neutrality relates, currently, to only the North Sussex Water Resource Zone. Water neutrality in this context relates to any development (not just housing) that could use more water post-development than its existing water usage.
Q. What’s the reason for restricting development?
A. Natural England issued a position statement in September 2021, under the Conservation of Species and Habitat Regulations 2017, which confirmed supplies from [Southern Water’s] groundwater abstraction [at Pulborough Brooks] cannot, with certainty, conclude no adverse effect on the integrity of the adjacent, internationally protected, Arun Valley sites; with a particular focus on the rare and endangered “little whirlpool ram’s horn snail” and its supporting wetland habitats.
Therefore, introducing the requirement for developments to achieve water neutrality to demonstrate with certainty, that the development will have no adverse effect.
Conversely, at present, there appears to be little to no evidence that can confirm whether the “little whirlpool ramshorn snail” is indeed affected by the groundwater abstraction for potable supplies at Pulborough Brooks. Due to this, no development that may increase the impact on this species can continue, until further investigation is completed (expected 2025) to rule the impact out.
Q. Can we assume this will be resolved soon given the water industry legislation stipulates that water authorities should accommodate water for new developments?
A. Not necessarily. Although it could be argued that the “system” has enough capacity to do just that, there appears to be a reluctance to count the good work that Southern Water has been doing to reduce abstraction from the affected source to allow development to continue (or start again given it’s been a year).
Q. I’ve seen the 85 litres per person per day (“lppd”) targets in previous reports, if we achieve this can we start to build again?
A. Not necessarily, although early reports and guidance indicated this suggestion, according to previous research by Southern Water even this reduced quantum of water usage would not allow for development to continue. However, there will certainly become a time when it helps according to the JBA Part B report.
Q. We are used to achieving 125lppd or even 110llppd how can we achieve 85lppd?
A. There is a myriad of options available. Personally we’re not fans of plot-specific rainwater/greywater harvesting solutions, but they do provide the opportunity to get to that level of water use with little additional fittings/fixtures amendments. Additionally, you can achieve the 85lppd target through an entirely fittings and fixtures based approach, however, this would require restricting items such as dishwasher, washing machine and even baths. We would implore anyone looking to reduce use significantly via fittings/fixtures only to review this thoroughly and take account of the end user.
Q. Could 85lppd be achieved via a site-wide system?
A. We are currently reviewing our proposal for a site-wide rainwater harvesting option to further reduce the use beyond 85lppd and to have the benefit of a dedicated management company, and so on. Site-wide harvesting would benefit the customer and increase long-term resilience to the system, but we appreciate it is not an orthodox solution for housing developments at the moment, although could be an intriguing solution in the future.
Jordan Gresham
Q. Can this spread to other regions?
A. We do not believe so. This issue is particularly concerning a single protected habitat that unfortunately is near the primary groundwater abstraction for potable use that Southern Water maintains. There are multiple resources within the area, with only a small proportion of the overall supply coming from the current subject source. Other areas and other authorities have similar setups, however, do not in theory impact protected habitats, with the Government having previously indicated they do not see this spreading to other areas in the same way. However, That is not to say we will not see more authorities considering water consumption, water reuse, greywater harvesting or other reduction measures.
Q. Are there any ways to mitigate this?
A. The one way to prove development can come forward at the moment is to offset the water expected to be used by the development. This could be through retrofitting existing homes and water saving for other existing users such as businesses etc. That said despite what others believe at the moment, for anyone other than the Water Authority, offsetting water on a scale is a very difficult task, particularly to pin to new development. We are working on several ways to achieve this and would be happy to assist anyone considering this, but be aware that it is quite an involved process so starting this route early is key.
If you would like more information on this topic, please contact Dean Knight: dean@richborough.co.uk or Jordan Gresham: jordan@richborough.co.uk