Estimating hidden and transient populations for Dwr Cymru Welsh Water

Dwr Cymru Welsh Water supplies drinking water and wastewater services to approximately 3.1 million people and 1.4 million homes across Wales and the border locations of England. DCWW is required to produce annual reports on the size of its ‘usually resident’ population, and also indicate the likely scale of its hidden and transient populations. Hidden and transient populations can have a permanent and/or seasonal impact, the latter relating to tourist populations in particular.

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The social and economic disruption driven by the COVID-19 pandemic resulted in significant changes to these figures, affecting the arrival of short-term residents, the use of second homes, the mobility of domestic visitors and international arrivals and departures. 

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To reflect this, Edge Analytics provided updated hidden and transient population estimates for DCWW’s area of operation, taking the latest available evidence into account and considering the impact of the easing of COVID-19 restrictions upon hidden and transient populations in particular. As domestic restrictions eased, while international travel remained restricted, DCWW sought to understand the impact on domestic tourism to Wales.

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Edge Analytics used its Hidden & Transient Population Model to estimate population totals in each Water Resource Zone and Wastewater Zone, taking account of specific sub-groups: irregular migrants; short-term residents; second address residents; domestic day visitors; domestic night visitors; and foreign night visitors.

Evidence was drawn from published research and reports, the latest statistical releases (from Welsh Government, Office for National Statistics and the Department for Work and Pensions), plus survey evidence on accommodation occupancy and domestic tourism trends.

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Edge produced a final report, accompanied by key datasets and data visualisations, providing the basis for DCWW’s strategic planning for hidden and transient populations.