The development description chapter of an environmental statement

The environmental statement development description is the chapter that decides what every other chapter is allowed to say. Get it loose and the ecology, noise and transport chapters will each assess something slightly different. Get it wrong against the drawings and the whole statement becomes vulnerable, because an assessment of a project other than the one applied for is an assessment of nothing.

Schedule 4 to the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 sets the content. The craft is in how you handle the parts that are not yet fixed.

An environmental statement must be prepared by competent experts under the 2017 Regulations. A drafted chapter structure is a starting point for that team, not a substitute for it.

Why the description controls the assessment

Every topic chapter works from the same source: the project as described. The noise assessment needs plant locations and construction durations. The ecology chapter needs the extent of vegetation clearance and the phasing. Transport needs trip generation, which needs floorspace by use. Air quality needs the construction programme and the operational vehicle fleet.

If the description gives each of those teams a different figure, or gives them nothing and invites them to assume, the statement will contain internal contradictions that an objector's consultant will find in an afternoon.

The description also sets the baseline against which any later amendment is judged. A scheme that changes after submission has to be tested against what was assessed, and a vague description makes it impossible to say whether the change is material.

So write it first, circulate it, and freeze it. Then version control it, because it will change anyway.

What Schedule 4 requires

Paragraph 1 of Schedule 4 is specific, and it is worth working through item by item rather than writing a general narrative and hoping.

• A description of the location of the development.
• A description of the physical characteristics of the whole development, including any demolition works required, and the land use requirements during construction and operation.
• A description of the main characteristics of the operational phase, in particular any production process, covering matters such as energy demand and energy used, and the nature and quantity of materials and natural resources used, including water, land, soil and biodiversity.
• An estimate, by type and quantity, of expected residues and emissions, covering water, air, soil and subsoil pollution, noise, vibration, light, heat and radiation, and the quantities and types of waste produced during construction and operation.

That last item is the one most often treated as optional. It is not. Quantified waste arisings and emissions by type belong in the description chapter, cross referenced to the topic chapters that assess them, and a statement that leaves them to be inferred is incomplete on the face of the Regulations.

"The whole development" also carries weight. Enabling works, temporary compounds, off site highway works, utility diversions and landscape mitigation outside the main site are all part of the project and all have to appear.

Parameters where detail is reserved

Most large applications are outline or hybrid, so the description has to assess something that is not yet designed. The approach is to define maximum and minimum parameters and assess the realistic worst case within them.

That approach derives from a line of cases concerning a Lancashire authority in the late 1990s and is now standard practice, with the Planning Inspectorate's own advice on the subject used widely outside the infrastructure regime it was written for.

What a parameters set normally fixes:

The trap is assuming one worst case serves every topic. The tallest building is the worst case for daylight and for townscape. A lower, wider footprint is often the worst case for ecology and for surface water. A compressed construction programme is the worst case for noise, while an extended one is worse for the duration of disturbance.

So each chapter has to state which combination of parameters it assessed and why that combination is the realistic worst case for its topic. Where a chapter cannot identify one, it assesses more than one scenario. Reviewers look for exactly this, and its absence is a standard ground of objection.

Construction: programme, plant and movements

This is where the description earns its place, because construction effects dominate the assessment on most schemes.

Set out the phasing with dates or with a duration from a notional start. State the working hours proposed, which will be secured by condition. Describe the compound locations, their areas and their duration. Give workforce numbers at peak. Name the plant: piling rig type and method, crushers, concrete batching on site or off, crane sizes and heights.

Then the movements. Heavy goods vehicle numbers per day at peak and as an average, light vehicle movements, staff trips, and the haul routes. Those numbers feed the transport, air quality and noise chapters directly, and the figures used across all three must be the same figures.

Piling method deserves a sentence of its own. Driven, bored or continuous flight auger produce different noise and vibration profiles, and a description that leaves the method open forces the noise chapter to assess the worst, which may then be secured by condition in a form the contractor cannot live with. A construction management plan later picks up the detail, and the description is where the envelope for it is set.

Demolition, earthworks and the material balance

Quantify, in tonnes or cubic metres.

Demolition volumes by material, with the structures identified. Any asbestos survey findings and the implications for the method. Earthworks as cut and fill with a stated balance, and where the balance is not neutral, the import or export tonnage and the number of vehicle movements that implies.

The cut and fill balance is one of the more useful disciplines in the whole chapter, because a scheme claiming a neutral balance and then importing 40,000 tonnes of fill has a transport and air quality problem that nobody assessed. State the assumption and state its sensitivity.

Site clearance has a seasonal dimension that belongs here rather than only in the ecology chapter. Vegetation removal outside the breeding bird season, or with a nesting check, is a project characteristic that constrains the programme, and the description should say so.

The operational description and its assumptions

For a commercial or industrial scheme this is where the production process goes, and Schedule 4 asks for it specifically.

Throughput or capacity. Energy demand and the source. Water use and its source. Process emissions to air and their abatement. Waste arisings by stream and their route. Hours of operation. Staff numbers by shift. Vehicle movements by type across a typical day and a peak day. External lighting, its hours and its control.

Every one of those is an assumption that someone will later want to secure or to test. Label them as assumptions, and say which are maxima and which are typical. An operational description written in the present tense as though the plant already exists invites the reader to treat typical figures as limits.

Where several developments in the area will operate at the same time, the interaction between them belongs in the chapter on cumulative effects rather than here, but the description has to be precise enough for that chapter to use.

Keeping the description consistent

Four documents have to say the same thing: the application description of development, the parameters plans, the development description chapter, and the schedule of conditions and obligations the applicant offers.

Practical measures that hold it together:

1. One person owns the description and issues it to every topic author, with a version number and a date.
2. Every chapter states the version it assessed.
3. A table at the end of the chapter cross referring each parameter to the drawing that fixes it and the condition that would secure it.
4. A reconciliation note explaining any change between the description submitted for the scoping opinion and the one in the statement.
5. A final consistency check against the application form before submission, which catches the floorspace figure that was updated everywhere except there.

The scoping stage matters more than people allow. A description adequate for scoping shapes what the authority agrees to leave out, and a material change afterwards reopens matters you thought were settled.

An environmental impact assessment is the most demanding document in the system and the chapter that fails it most often is the one everybody assumes is easy. The wider list of report types shows which topic chapters a given scheme is likely to need behind it.

For specialist technical reports, qualified professional input may be required. This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

Draft the structure of your environmental statement chapters on PlanScope, then hand them to the competent experts who will complete them.