How to Prevent the Spread of Invasive Species When Starting a Construction Project
Invasive non-native species such as Japanese knotweed, Himalayan balsam and giant hogweed are today one of the largest – and most underestimated – risk factors in construction projects.
Incorrect handling of soil can lead to project delays, increased costs, regulatory non-compliance and long-term environmental damage.
The good news is that much of this risk can be eliminated before the first shovel hits the ground – if the right decisions are made early.
Below are the key steps every project should follow.
1. Identify invasive species before the design phase begins
The first – and most important – step is to understand what is present on site.
- Carry out an early ecological / environmental survey
- Identify:
- invasive plant species
- areas at risk of spread
- existing soil that may be contaminated with seeds, roots or plant material
👉 Projects that overlook this in the early phase often experience:
- sudden stoppages on site
- costly emergency measures (often dig & dump)
2. Understand that soil is biological material – not just bulk mass
Soil containing invasive species is not inert waste – it is a biological risk material.
Common mistakes include:
- temporary storage without containment
- transporting soil between multiple locations
- reusing soil without treatment
The result can be unintentional spread both within and beyond the project area, often not discovered until months or even years later.
3. Plan soil management as part of the overall project logistics
Soil should be treated as a dedicated workstream, just like concrete, steel or logistics.
Well-managed projects:
- clearly define which soils are “clean” and which are “risk material”
- establish clear procedures for:
- excavation
- temporary storage
- treatment or final use
- avoid unnecessary transport and re-handling
👉 This leads to better control, lower costs and fewer surprises.
4. Avoid “dig & dump” as the default solution
Excavating soil and sending it to landfill has long been the standard response to invasive species. In practice, this approach is often:
- expensive
- logistics-intensive
- dependent on limited landfill capacity
- environmentally unsustainable
Across many parts of Europe, millions of tonnes of biologically contaminated soil are handled this way every year – despite the soil itself often being of high quality.
5. Consider treating soil on or near the construction site
Modern projects increasingly view soil treatment as an alternative to landfill.
Key benefits include:
- reduced transport and disposal costs
- elimination of spread risk
- enabling safe reuse of soil within the project
- improved documentation and control
For many projects, this can be the difference between a reactive and a proactive environmental approach.
6. Document – for authorities, clients and future liability
Regardless of the method used, documentation is critical:
- What was identified?
- How was the soil handled?
- How was biological risk eliminated?
This protects:
- the contractor
- the client
- the developer
— both legally and financially.
Final thoughts: Start right to avoid costly consequences later
The spread of invasive species is rarely the result of bad intent – but often of insufficient planning in the early stages.
The most successful projects:
- take biological risk seriously
- plan soil management strategically
- choose solutions that reduce both environmental impact and cost
At SoilSteam, we work with contractors and developers who want to:
- eliminate biological risk in soil
- reduce reliance on landfill
- enable safe reuse of soil
👉 Engage early in the project phase – that’s where the best solutions are created.