The Tararua Ranges had provided a wealth of information for Year 12 geographers, he said, who collected data from different vegetation zones in the Mount Holdsworth area for an internal assessment.
The native bush in the area had provided a practical application of data collecting equipment and "another local landmark", the Ruamahanga River, had in February rewarded nearly 70 Year 11 geographers with information towards the sustainable use of the waterway, he said.
Year 11 geographer Jessie Wilkinson said the aim of their field trip was to look at sustainable uses of the Ruamahanga River by checking water quality and peoples uses.
The classes went to four sites: Kiriwhakapapa, Double Bridges, Wardells Bridge and Gladstone Bridge.
"We collected this data so we can make a report discussing the issues around the river and its uses. We did an environmental assessment at each site by looking at algae, stock access, litter, shade and smell."
Water quality was tested and students measured the width of the river as well and took general notes of what was noticed at each site.
The classes found Kiriwhakapapa was the cleanest site "as there was no stock access upstream and it was hardly used by humans", Ms Wilkinson said.
Double Bridges was found to be the most popular river for recreational uses such as swimming. Wardells Bridge was the worst site because upstream there was a sewage plant and the Masterton dump, and it also was hardly shaded by any trees, which created algae on the rocks, she said.
"Gladstone Bridge had the widest river channel and there was also no trees shading the water so there were lots of algae on the rocks. The water quality got worse as we got further downstream."