Several homeowners whose backyards face the Whakatāne River are shocked to find out how much land they will lose use of when remedial work begins on the stopbank.

Riverside Drive residents, some of whom have been living there for over 30 years, have built accommodation and sheds that they are now being told will have to be removed along with decking and fencing around pools.

Hundreds of thousands of dollars' worth of landscaping will be undone and well-established gardens and trees of sentimental value will be destroyed.

Letters were sent out by Bay of Plenty Regional Council at the end of March to Riverside Drive households whose backyards encroach on the stopbank, telling them of its plans to remove structures, trees and other plants that are outside their legal boundaries.

The programme of work the council is calling Safeguard our Stopbank, is expected to take place over the next two to three years.

The first stage of the project has already begun, with several properties along Henderson Street having trees, fences and other structures removed and new fences constructed on the legal boundaries.

Soon to be affected homeowner Chris Burn says a group of Riverside Drive homeowners plans to join forces to kick back against the regional council's plans.

'I'm in the process of speaking to people in the neighbourhood about arranging a street meeting and trying to involve a couple of people with knowledge of what the make-up of the stopbank is.”

Some homeowners the Beacon spoke to say the regional council has a very different idea of where their property's boundary lines are than they were provided with when they bought their properties.

Some have been shown a new boundary line that effectively cuts their backyard in half.

Even the land that the regional council agrees belongs to honeowners is affected by the Flood Protection and Drainage Bylaw 2020, which states that authority must be sought from the council before building structures, planting or removing plants within 12 metres of the stopbank or to carry out any earthworks deeper than 30 centimetres within 40 metres of the stopbank.

The 40-metre zone would encompass their entire property and reach homes across the road.

Another property owner says before they built the deck around their swimming pool they sought the council's advice because there was a garden with a retaining wall where they wanted to build.

The council staff member told them to simply build over the top of it. After spending thousands on the decking and fencing, they are now being told that because they do not have written authority, only verbal advice, it must be removed.

"I've been here 25 years," says Mr Burn, a retired teacher. 'When I bought the property, I was told by the land agent that we weren't allowed to do anything on the top and the steep bit of the stopbank - and no permanent structures.

"We were told nothing about vegetation. It came as a bit of a shock when they came and told me I would have to remove everything down to about a metre from where I walk down off my deck.

"Three trees I've got growing here are 25 years old and they were given to me by my deceased father in remembrance of him being captured on Crete and they are of real sentimental value to me. I have a 15-year-old kauri that's growing here, and I don't want to chop that down."

The council has not yet advised landowners whether they will have to pay for the removal of any trees or structures themselves, saying they will assess each property individually. Mr Burn referred to this individual assessment as a 'divide and conquer” strategy.

"If they say I have to remove them myself I am not going to," says Mr Burn.

He says he probably has the least to lose of all his neighbours.

Garry Rusden shows where the Bay of Plenty Regional Council says his property ends, despite his own plans showing the building is within his boundary.

Next door, Garry Rusden has a one-bedroom flat straddling the new boundary that, according to the Whakatāne District Council plan that their lawyers looked at when they bought the property, is well within their boundary.

It was built in the 1980s, but according to where the regional council says it is going to place the boundary fence, it is too close to the stopbank. He describes the regional council's plans as a landgrab.

Mr Burn does not question the necessity of ensuring the integrity of the stopbank but wonders if the council has investigated other methods that would cause less upheaval for homeowners.

Over the past five years he has watched the strengthening of the opposite side of the river by the placement of rocks.

'Let's think a little bit outside the square here. Why doesn't the council strengthen this side of the stopbank?

'It's not a huge leap. It would cost money, obviously, but would be better than upsetting the 50 or so houses involved and dropping the value of their properties by hundreds of thousands of dollars and cut their backyards, basically, in half.”

Regional council engineering project manager Paula Chapman says the council has a responsibility to ensure assets like stopbanks are resilient and will keep communities safe in a significant flooding event.

'This means the council is constantly reviewing the town's flood protection assets and looking at ways to protect them as we know some activities and practices can be detrimental to our stopbanks,” she says.

Mrs Chapman told the Beacon the council now has a much better understanding of how damaging stuctures and trees can be to the stopbank than it had previously.

She says global warming and the increase in severe weather events means there is increased risk of flooding.

'No one wants a river running through their section.”

One of the biggest threats to the stopbanks was tree roots that could be as large below ground as above. When the tree roots died off, it could leave huge holes in the stopbanks.

She says building up the stopbanks on the river side would not only be costly but also ineffective in improving the structural integrity of the stopbank.

'We would still have the same problem that we have now. Over the years, people have built structures and planted trees outside their boundaries and as time's gone on these non-approved structures and different types of vegetation have gradually advanced or encroached beyond where they should have.”

The first stage of works is being done from Ferry Road to upstream of the Landing Road Bridge and will continue over the next month.

The council will reduce physical work over winter, but will continue to investigate other areas along the stopbank that will need remediation work later in the year.

It is also reminding residents to check with the regional council first if they're wanting to do any work near a stopbank, as people will need to consider whether a bylaw authority is needed.

This authority is written permission from the regional council, with conditions attached, that outlines what a landowner must do to ensure the flood protection structure is not damaged or compromised.