Waste stream forecasting in a site waste management plan

A construction waste forecast is the part of a site waste management plan that a council can actually test, and it is usually the part written last and least. The Site Waste Management Plans Regulations 2008 were revoked in England in 2013, so there is no longer a statutory duty to produce one. What remains is a planning condition, a local policy requirement, or a BREEAM credit, and all three expect a quantified forecast by material stream with a diversion target attached.

The forecast has a second purpose that pays for itself. A plan that predicts 400 tonnes of concrete arising from a demolition, and identifies a crusher hire and a reuse destination on site, turns a disposal cost into a materials saving. That calculation is the reason to do this properly rather than to a template.

What the plan has to forecast

Read the condition wording first, because the required content varies. Most conditions ask for four things.

• Estimated quantities of waste by material stream, in tonnes, with volumes where the material is bulky.
• The proposed management route for each stream: reuse on site, recovery off site, recycling, or disposal.
• A diversion from landfill target, expressed as a percentage by weight.
• Arrangements for recording what actually arises, and for reporting against the forecast.

Where the condition also asks for the waste hierarchy to be applied, say so explicitly and in order: prevention, preparing for reuse, recycling, other recovery, then disposal. The duty to apply the hierarchy sits in the Waste (England and Wales) Regulations 2011, and quoting it costs a sentence.

Distinguish the document from an operational waste strategy for the finished building. A Site Waste Management Plan deals with construction and demolition arisings, while a Waste Management Strategy deals with bin stores, container capacity and collection once the building is occupied. Conditions sometimes conflate them, and a plan that answers the wrong one gets refused.

Estimating quantities by material stream

Build the forecast from the schedule of works rather than from a rate per square metre, and use the rate only as a sense check at the end.

For a demolition, take the areas and thicknesses off the survey drawings and convert with material densities. For new build, take the bills or the outline quantities and apply a wastage allowance to each material. The wastage allowance is where professional judgement earns its place: cut and fill on groundworks, offcuts on timber and plasterboard, overordering on blockwork and packaging on everything delivered.

State the source of every rate you use. A forecast built from your own completed projects is stronger evidence than a published benchmark, and either is acceptable so long as the basis is named. Figures with no stated basis are the reason these plans get queried.

Asbestos deserves its own line. A refurbishment and demolition survey under the Control of Asbestos Regulations 2012 has to be carried out before work starts, and the results change both the forecast and the programme. Where a survey has not yet been done, say so and flag the quantity as provisional rather than putting in a number.

Setting diversion and reuse targets

Pick a target you can achieve and evidence. A stated diversion figure becomes a condition, and a plan that promises a figure nobody can report against creates an enforcement problem for the developer.

Two separate targets are worth distinguishing. Diversion from landfill by weight, which is heavily influenced by whether inert material is crushed and reused on site, and reuse on site as a proportion of arisings, which is the figure that actually reduces vehicle movements. Reporting both tells a better story than a single headline.

Where the site has an existing building being taken down, a Pre-redevelopment Audit identifies materials and components worth recovering before demolition begins, and its findings feed directly into the reuse target. Doing that audit after the demolition contractor is on site is too late.

Segregation on a constrained site

Segregation is a space problem. On an urban site with no room for six skips, the honest answer is a smaller number of streams on site plus off site sorting at a licensed facility, with recovery rates evidenced by the operator's own data.

Say which arrangement you are proposing and why.

1. Full segregation, where space allows: separate containers by stream with clear signage.
2. Partial segregation: inert and hazardous separated on site, with a mixed container for the rest sorted off site.
3. Sequenced segregation: one or two streams at a time, matched to the trade on site that week, which works well on refurbishments.

Then name the facility and ask the operator for their recovery rate. A recovery rate from the receiving facility, in writing, is what lets you report against a diversion target when the containers left site mixed.

Include the practical items too: container positions on the site plan, wheel washing, road sweeping, and the point where the crusher will sit if inert material is being processed. Those belong in the Construction Management Plan as well, and the two documents should agree.

Duty of care records and carriers

Section 34 of the Environmental Protection Act 1990 imposes the duty of care on anyone who produces, carries or disposes of waste, and the records are the evidence of compliance.

Four record types cover a construction site. Waste transfer notes, or season tickets for repeat movements, describing the waste and its European Waste Catalogue code. Hazardous waste consignment notes for asbestos, paints, oils and contaminated soils. Carrier registration checks for every operator used. And permit or exemption checks for every receiving site.

Assign responsibility for keeping them to a named role on the contractor's team, and say in the plan that copies will be made available to the local planning authority on request. An officer discharging the condition at practical completion will ask for the transfer notes and a reconciliation, and a site that has kept them in a lever arch file rather than a shoebox discharges in days.

Reporting actual against forecast

Set out the reporting arrangement in the plan itself: what is recorded, how often, in what units, and by whom.

A workable arrangement is a monthly log of tonnages by stream, taken from transfer notes and weighbridge tickets, reconciled against the forecast, with a short explanation of any variance above a stated percentage. Explaining variances honestly is better than adjusting the forecast retrospectively, and officers respond well to a plan that says the demolition produced more inert material than expected and more of it was reused.

Keep photographs of the segregation arrangement in use. They answer the question of whether the plan was implemented, which is a different question from whether the targets were met.

Making the plan conditionable

Write the plan so the condition can be discharged from the document itself.

Name the person responsible. Give the forecast in a single table with a stated basis for each rate. State the diversion target and the reuse target separately. Describe the segregation arrangement and the receiving facilities. Set out the records to be kept and the reporting cycle. And provide a short closing statement listing exactly what will be submitted at practical completion.

Then check the plan against the condition clause by clause before submitting it, because the most common reason for a refused discharge is a plan that is perfectly good and answers a slightly different question.

This article 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.