Beachcombing is a powerful scientific tool, local children learned last week.

Nine pupils from Waiwera South School and principal Kaz Bisset joined two local environmental experts at Kaka Point to discover how collecting litter meant more than tidy beaches.

‘‘Today we’re collecting rubbish, weighing and counting it to compare with next term and as the years go past,’’ Millie Martin, 11, said.

On Kaka Point Beach the team collected every scrap of rubbish they could find inside a designated 100m by 20m area then weighed, separated and counted it to add detailed data to an ongoing national litter intelligence survey.

‘‘It’s a national citizen-science project run by Sustainable Coastlines where we do long-term surveys of particular sites, four times a year, to understand year-round litter flux and content,’’ New Zealand Marine Studies Centre educator Hannah Drury said.

Kaka Point Bowling Club made its premises available for the team’s base and after lunch the litter collection was repeated at Port Molyneux beach.

‘‘This is ideal for the Enviroschools initiative,’’ Clutha District Council waste education officer Scott Martin said.

‘‘Incorporating sustainability into their learning empowers students to care for their local communities because they can actually measure the positive impact they can make.

‘‘It’s inspiring to see the kids’ engagement — it makes me hopeful.’’

The citizen scientists gathered 2.74kg of litter at the Kaka Point Surf Lifesaving Club survey area last Tuesday, compared with 0.47kg collected on September 23 last year.

The recent overview counted 103 mostly glass litter items per 100sq m.

Litter intelligence survey data is available for anyone to analyse for themselves at