This was a problem Leeston Consolidated School year 6 pupils were tasked with solving.
To do this they visited the site and made a plan to create shade to suppress the weeds.
The plan involved reshaping the banks which were too steep to plant on, designing a planting plan and adding some features in the stream, such as boulders and wood for habitat.
Fulton Hogan provided earthmoving equipment and operators to reshape the bank as the pupils had designed it.
The pupils returned last week to do the planting and position the boulders.
Fulton Hogan South Island resource and sustainability manager Don Chittock said the firm was happy to be part of a restoration project that involved a local school and would lead to improvements downstream in the Selwyn/Waikirikiri River.
The pupils were guided by Matt Stanford, from the Enviroschools programme, who said the project was an opportunity to connect young people to a local waterway so they could learn the issues around them and how to care for them.
''What was particularly great about this project was the students were involved right from the beginning with all the planning and design and then they got to see it to fruition,'' Mr Stanford said.
Snake Creek flows into the Silverstream River and then into the Selwyn/Waikirikiri River upstream from Coe's Ford, just south of Lincoln
The project was part of a wider project being carried out in Snake Creek by the Water and Wildlife Habitat Trust in partnership with landowners and multiple funding partners to restore around 3km of the waterway.
There were also other projects in the catchment on Silverstream and McGrath's Stream.
A crowd funding campaign was being run to help restore an 875m section of Silverstream. To find out more, visit the Million Metres Stream Project website: millionmetres.org.nz/open-project/restoring-a-tributary-of-the-selwyn-waikirikiri-river.
Groups involved in project funding included: Rata Foundation, Living Waters - Department of Conservation, Fonterra, Environment Canterbury, Fulton Hogan, Selwyn District Council, Pub Charities, Fish and Game and the Ministry for the Environment.
-By David Hill
Central Rural Life