If you’re looking to abstract groundwater in the UK, you may be wondering whether a step test or a constant rate pump test will be required. This article explains the role of step tests and constant rate pump tests within the abstraction licensing process.
Why Are Pumping Tests Required?
Pumping tests are used to demonstrate that a groundwater abstraction can be carried out sustainably without any negative impacts. The Environment Agency relies on pumping test data to understand how an aquifer responds to abstraction.
Pumping tests are used to confirm that:
- The borehole can physically deliver the proposed abstraction rate
- Drawdown remains stable over time
- Nearby groundwater users are not adversely affected
- Rivers, wetlands, and groundwater-dependent ecosystems are protected
What is a Step Test?
A step test is the initial test carried out on a borehole, particularly for new groundwater abstractions. During a step test, the borehole is pumped at a sequence of increasing flow rates. Each step runs for a set period while water levels are monitored, before the pumping rate is increased again.
When is a Step Test Required?
A step test is generally required where there is limited or no existing performance data for a borehole. This most commonly applies where:
- A new borehole has been drilled
- An existing borehole has been deepened, rehabilitated or modified
- Previous abstraction records are unavailable or unreliable
- The regulator needs confirmation that the borehole can operate efficiently at the proposed pumping rates
What is a Constant Rate Pump Test?
A constant rate pump test is used to assess the response of the aquifer over time. Once a suitable pumping rate has been identified, the borehole is pumped continuously at a fixed rate for an extended period, often at least 24 hours.
When is a Constant Rate Pump Test Required?
A constant rate pump test is usually required where the regulator needs evidence that an abstraction is sustainable in the long term. This commonly applies when:
- Applying for a new abstraction licence
- Increasing abstraction volumes under an existing licence
- Supporting planning applications for new developments
- Demonstrating that environmental impacts will be acceptable
How Nicholls Can Help
As a UK water consultancy and licensing specialist, we offer independent advice on whether a step test, a constant rate pump test, or both are needed. We can help with test planning, liaising with regulators, interpreting results and preparing clear reports that meet Environment Agency requirements.
Contact our team today if you are planning a groundwater abstraction and are unsure what testing will be required.
