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Water Impact Assessment

A water impact assessment looks to safe guard perhaps the most important resource in the world, with only 1% percent of all fresh water on the planet being in a drinkable form, and most of that being under ground. With drought and flooding becoming wide spread even in the UK water impact assessment is an important and wide reaching aspect of EIA.

Water is such an intrinsic part of the environment that the water assessment component of the EIA will likely influence other components such as visual impact, soils and geomorphology.

Do you require a Water Impact Assessment? Please contact SWEL for a quotation. Discussed below are relevant sectors, that may require a water impact assessment:



Water Sports

Water sports taking place in fresh water environments such as lakes and reservoirs may require a water impact assessment. The typical focus we have observed is pathogenic impacts on water quality in reservoirs, and we have written 2 reports on this subject since 2015. A report in this instance would include a baseline survey (which typically shows higher levels of pathogens in the summer months. Pathogen are not necessarly due to human uses of the water body, and are present from birds, and agricultural run off.


Overt he last 5 years or so ( as of 2024) we have seen more and more data emerging about the poor state of our sewage infrastructure in the UK. This has manifested itself in the increased use of storm overflows, and increasing nutrient levels in protected rivers.

It is also clear that sewer companies will state that they have "capacity" for additional inflow, even when the receiving infrastructure is not treating the water very well. For example excessive use of combined sewer overflows.

So in the case of new housing it is sometimes justified to ask for a water quality assessment, and in nutrient affected catchment this is quite common, with reports in this instance being badged as Nutrient Neutrality and Mitigation Assessments (NNMAS).


Creation of the new water abstraction (for brewing or malting's for example) may have an impact of water cycle in a given catchment.

Water Impact is assessed on the basis of its quantity, its quality and its stake holders.

Assessing impact of water quantity will involve looking at the project as part of the local water cycle, how will the development add or subtract from that equation. Inputs such as rainfall, and inflow will be considered, and losses from evaporation and runoff will be studied to create a water balance for the study area.

Elements taken in to account in the Water Impact component of environmental impact assessment are:

-Surface Waters

Water quality impact is also assessed, and will include benchmarking of current levels of determinants and the developments likely impacts of these levels in relation to current local EQS. The above OS map is reproduced under our PMCL, which is updated annually.

Case Study

Read About Water Impact Assessment Case Study for a Water Sports Use in a Reservoir.