Ecosystem Enterprise Partnership – Building Natural Solutions

Calculations of the phosphorus impact of proposed affected housing developments within the Pembrokeshire Local Development Plan

Completed with the consultancy support of ADAS and in the absence of a nutrient budget calculator for Pembrokeshire it was required to procure support to calculate the impact of the affected proposed developments within the Pembrokeshire Local Development Plan. Working with the Planning department of Pembrokeshire County Council, 8 proposals were identified as being affected by the phosphate planning guidance.

The phosphorus impact of these 8 proposals were calculated individually providing targets for each and a total amount of impact. Methodologies used were broadly based on those used by Natural England, and considered the Carmarthen Nutrient Budget Calculator which went live while delivering these calculations. The methodology follows a 7 step approach:

• • Step 1 – Calculate additional population
  • Step 2 – Confirm water use
  • Step 3 – Confirm Waste Water Treatment Works (WWTW) and permit level
  • Step 4 – Calculate total phosphate (TP) in kg per annum that would exit the WWTW after treatment
  • Step 5 – Calculate the P loss from existing land use
  • Step 6 – Calculate the P loss from the proposed land use
  • Step 7 – Calculate the overall P budget with an uncertainty

This work shows that a total of 313kg of phosphorus would need to be removed to achieve ‘nutrient neutral’ status from the 8 proposed housing allocations within the affected area of the phosphate planning guidance.

The calculations are presented in total phosphorus, using an estimated discharge level of 8 mg/l wastewater generated, accounting for over 85% of the total phosphorus requiring mitigation for each development.

‘Nutrient Loss Risk’ Modelling to enable better consideration of location of nutrient mitigation options

Completed with the consultancy support of Environment Systems. This work intended to inform where mitigation methods would be best placed to reduce nutrient entering waterways. The aim was to host this information where it can be easily viewed alongside other existing information on biodiversity, connectivity and wider conservation information. The Land Use Planning Tool hosted by West Wales Biodiversity Information Centre was chosen to fulfil this role.

This was done by looking at the nutrient loss risk across landscapes based on a number of factors including soil type, topography, and land use. The results were modelled in a heat map format showing the risk related to different areas, the highest contributing factor (i.e., soil type or topography), and the potential for buffer strips to be used as a mitigation method. As Ceredigion and Carmarthenshire are facing similar challenges related to phosphates and SAC Rivers, it was decided to complete this work across all three counties which provided cost savings in delivering the modelling. This scale also works well as the additional information within the Land use Planning Tool is available across all three counties.

The modelling is completed and has been loaded on to the Land Use Planning Tool, alongside a report which provides information on the data and methodologies used to produce the modelling.

Mitigation plans providing opportunities for achieving ‘Nutrient Neutrality’

Completed with the consultancy support of Environment Systems. This work demonstrates phosphorus mitigation plans designed to support planning for Habitats Regulation Assessment for 3 actual developer’s sites, identified with input from the Pembrokeshire County Council Planning Team. The developer sites are located in Narberth, Wolfscastle and Cilgerran.

A fourth mitigation plan was created to propose a plan to remove the total agreed phosphorus impact of the 8 affected sites of the Local Development Plan(LDP) as a whole.

The mitigation plans are a series of opportunity maps, accompanied by technical commentary outlining the methodology and testing of the evidential basis for the recommended land management interventions necessary to meet the agreed amount of phosphorus reductions.

Mitigation Plans Methodologies

Produced alongside the individual mitigation plan reports, is a paper outlining the suggested mitigation methods, the mapping and modelling methodology, key findings, potential next steps and a series of supportive appendices.

Guidance on nutrient neutral agriculture development

Completed with the consultancy support of Lichfields. This work has provided guidance specifically aimed at farmers and planners related to how the NRW phosphate planning guidance applies to agriculture development. This has identified and aims to raise awareness of the anticipated requirements of information to be provided by farmers, and the ability to address nutrient neutrality in a farm business setting.

Quantifying the Phosphorus reduction of the Building Resilience in Catchments(BRICs) Development Plan

The Building Resilience into Catchments(BRICs) project which precedes the Ecosystem Enterprise Partnership – Building Natural Solutions work created a development plan for a Nutrient Trading Scheme for the Celddau Catchment. This was focused on nitrogen as the Pembrokeshire Marine SAC was used as the body of water to improve, as nitrogen has larger concerns in a saltwater environment.

The BRICs work proposed to deliver 400 tonnes of nitrate removal across Pembrokeshire over a five year period. The first 115 tonnes was understood as most agreeable by farmers and at a lower cost than the remaining 285 tonnes, which uses mitigation methods more challenging to implement.

This work quantifies the phosphorus reductions of the mitigation actions proposed in the BRICs work and shows that at the point of removing 115 tonnes of nitrates, between 1 and 2 tonnes of phosphorus removal can be achieved depending on the targeting of high-risk areas. The remaining 285 tonnes of nitrates could remove between 4.6 and 7 additional tonnes of phosphorus, though at a higher delivery cost.