"They're a good way for us to cover a lot more ground than we can by car and highlight where the risk areas are.
"Any issues we see during those flights, we would follow up in person with a visit. So, it's really about just identifying where there may be risks.
"A number of high-risk sites were identified last season and were followed up with farm visits to 'ground truth' the aerial observations."
Saunders said the council's overall compliance activity last year showed farmers had properly planned for winter grazing activities and he hoped that would continue.
"This season we'll be taking note of any high-risk sites and will be visiting the area to inspect issues on the ground."
New government regulations for winter grazing come into effect from November, after this winter.
But Saunders said farmers should already be thinking about next winter, as some will need to apply for consents.
He said there were key changes to the regulations, for instance, the addition of critical source areas such as gullies and swales.
"This means that these areas should be left ungrazed unless consent is sought."
Saunders was expecting thousands of consent applications to come through before the end of the year.
There were several ways to protect critical source areas, such as avoiding cultivating them, not grazing them, leaving adjacent grass buffers intact or fencing off steep parts of the areas.
Farmers could also look at installing multiple small sediment traps, ensure subsurface drains were not feeding into the area and consider planting natives such as toitoi, flax or carex, Saunders said.
Farmers needed to check the slopes of land they are thinking of grazing and consider what risks there are to manage.
"The slope of any land, under an annual forage crop that is used for intensive winter grazing, must be 10 degrees or less, determined by measuring the slope over any 20-metre distance of the land."
- RNZ
