"We have got all but one farmer in the catchment on board and it has made a huge difference," Ms Mato said.
The catchment runs through farmland and adjacent to forestry, which means there is a lot of run off.
"It is not easy but we have created a riparian strip either side of the river to keep the everything at bay and we have improved erosion by fencing off the area."
Since starting the project the group has planted up to 20,000 plants and this work is set to continue well into the future.
"We are now also focusing on the eradication of pests as well as looking at developing proper walkways through the catchment for visitors to enjoy."
Ms Mato said during the last two summers they allowed people to ride bikes and walk along a track, which ended up out by the sea.
The group hold community planting days and meetings where family and friends can get together and do their part to help improve fresh water quality.
"The only thing is we need to find more funding, as it is getting dampened down with the introduction of new environmental projects."
Mr O'Brien said to be sustainable and for them to carry on with their long-term vision, sponsorship was needed.
"It has been a successful community project so far but to look to the future we need to look at our funding."
For more information and to see how you can help visit whangawehi.com/about/.