The pressure of new homes on the environment

We are all aware of the Government targets to increase housing supply, with a Nationwide target of 300,000 new homes per year. Presently the achieved figure is about 130,500 homes per year. (reference “Stimulating housing supply – Government initiatives 20 April 2020”) These targets are reflected in the Local Authorities in and around the Solent.

Developers, and their Architects, have been concentrating, for many years, on “sustainability”; low carbon outputs from materials and building methods. This was administered by a complex Code for Sustainable Homes (now withdrawn). These requirements concentrated on energy usage, resulting in greenhouse gas emissions, which contributed to climate change. The long term aim was to make housing “energy positive” which, in this country, is far from being realised.

We have become increasingly aware of the potential damage by new development to the environment, not only visually, but in terms of pollution by way of additional nitrogen and phosphorus output into the waterways and the water treatment system, which in itself, is overloaded and unsustainable.

Run off causing green algae bloom

The water environment within the Solent region is an important area of wildlife, is internationally recognised, is an EU-Protected site, and protected under the Water Environment Regulations and the conservation of Habitats and Species Regulations. Any development within this region has the potential to impact upon the Local Environment and the Solent Complex. The problem of new Housing Developments is that they increase the run-off of waste water, which is rich in Nitrogen. This, in turn, increases algae bloom which can severely damage the ecology of wildlife habitats, particularly the bird population. The rivers Itchen and Test show high levels of nitrate and phosphates which lead to the growth of this algae.

Following an EU Directive and court ruling on protective sites (2018) non-binding advice was issued from Natural England (NE), which stated that developments bordering the Solent must be Nitrate-Neutral, (target 2030). This had the effect of “freezing” development within the Solent Region and meant that Local Authorities could not deliver on their housing targets. The Local Authorities have been working with Natural England, Southern Water and the Environment Agency (EA) in an attempt to solve this problem.

Natural England has produced a guidance document to encourage nutrient neutrality, by way of “Nitrate Credits”, with a contribution payable by the developer. This was initially introduced by Portsmouth City Council to solve the Nitrate crisis. The NE Nitrates Guidance document can be found, along with other reference sources, at our nitrates reference page.

Current examples of mitigation proposed by Local Authorities

Fareham Borough Council (FBC) appears to be proposing to use an additional contribution to the established Section 106 legal agreement, to cover specific developer contributions, which would be attached to any specific Planning Permission. Payment
would be made by the developer once the project proceeds. This gives the Local Authority (LA) a means to charge a specific site mitigation. By way of an example, FBC are proposing to improve the wastewater treatment works at Peel Common and would seek funds to enable this to be achieved.

Portsmouth City Council has developed a strategy whose overall aim is to reduce the wastewater sent to Budds Farm treatment works in Havant. They have identified that the strategy could create enough credits to provide an additional 518 homes per year. Portsmouth City Council presently plans to build 584 dwellings per year.

Eastleigh Borough Council (EBC), which had a target of 5,300 homes, are already asking that the Developer contributes a sum of £4,500 per dwelling, which relates to land cost and ongoing maintenance. This will be used to identify areas of agricultural land and remove these from high nitrate use to a lower intensity use thus, in theory, offsetting the nutrients produced by new housing developments. EBC have recently had their “local Plan” proposals rejected by the Planning Inspectorate and hence it is not known how they will achieve these targets.

Although land within the City is limited. Southampton City Council have a target of 726 homes, a £144m investment. The Council have published a “City Vision” in the form of Habitats Regulations Assessment and Sustainability Appraisal. The Vision includes water courses, soil resource, coastal defences, air quality, etc.

The Isle of Wight has a huge government target of 9600 homes or 641 homes per year with a population only 55% of Southampton.

Fareham Borough Council are projecting 2,700 homes over the next 5 years, at approximately 500 homes per year. Havant appears to have a shortfall of 4,800 homes until 2036. New Forest District Council has a projection of 1,380 to 2036, which includes Fawley Village 380. These are target figures available as at August 2020. They may vary with updated policies.

In addition Local Authorities have also joined with the Solent
Recreation Mitigation Strategy, a way of safeguarding the countryside for public recreational use, by raising funds from further payment by the developer. This is set by the each LA as a contribution per dwelling.

All these contributions are in addition to the existing Community Infrastructure Levy (CiL). This is an established Government directive (revised 2019) by which LAs can apply a levy to support community infrastructure such as roads, pavements, cycleways, green spaces, playgrounds, etc.

Will the Nitrate Credits be enough to safeguard the Solent Wetlands?

The preceding figures illustrate that our Local Authorities are developing strategies whereby they identify areas of agricultural land, which may be removed from a high nitrate intensive use to a lower intensity use, offsetting the nutrients produced by new housing developments. This, in theory, will ensure no net increase in nitrates within the Solent, but has yet to be proven in practice. It also loses good agricultural land which conflicts with the Agricultural and planning policies, which will contribute to a net loss of soil resource (Agriculture) and sterilisation of land. However, developers do have a responsibility to identify the steps they intend to take independently to achieve Nitrate-Neutrality within their proposals, including opportunities to work with third party landowners. There are still the issues of additional nitrogen and phosphorus output seeping into the waterways and overloading the public sewers and treatment plants, already surcharging during inclement weather. The developer still has to provide an effective sustainable drainage system, but in many instances, it connects to an existing overloaded drainage system and treatment works.


These mitigation credits mean that, in theory, development can proceed and Local Authorities can plan to meet their housing targets. Will the measures now in place, through the planning process, be enough to safeguard our local environment and will mitigations through Nitrate Credits be effective? There is a danger that mitigation through financial contribution will just be another cost to add to the development, in addition to the cost of appropriate consultants to examine the local and wider issues. The management by Local Planning Authorities will be influenced by the need to supply the additional houses in accordance with Government targets.

The Solent Protection Society will continue to monitor local development and make appropriate comments on these evolving planning policies. In particular Local Authorities’ identification of appropriate sites for development, their proposals to offset local agricultural land and those so called “Nitrate Credits” which allow development to proceed.