There's no point investing $20.6 million into stormwater upgrades to prevent pollution in Ahuriri Estuary unless Napier residents change their dumping behavior, the council says.
The Napier City Council's environmental team recently photographed a part of the stormwater system on Munroe St filled with bottles, cans and foam peanuts used in packaging.
While the blockage caused by the dumping looks extreme, the council says it merely shows the challenges its teams deal with on a daily basis.
NCC's environmental solutions manager Cameron Burton said his team often sees items like rubbish bags, tyres, oil and dirt in the city's waterways.
They also regularly see dead shellfish, evidence that what is going into Napier's waterways is having a negative impact on the environment.
The team once got a report of someone emptying a beanbag down the drain, and have seen pipes leading into the waterways emptying chemicals strong enough to corrode concrete into the stormwater system.
The council was investing $20.6m over the next 10 years in stormwater improvements across the city, Burton said.
"But there is no point us spending that amount of money if individuals don't take responsibility as well."
Burton said he believes a lot of the behaviour is inadvertent. To help with education, the council has come up with 10 things Napier residents can do to limit their environmental impact on the estuary.
"The most important message for everyone living upstream of the estuary is that only rain should drain to the stormwater network and out to the ocean," Burton said.
He suggested checking your plumbing, because some houses in Napier have their stormwater incorrectly connected to the wastewater system.
During periods of heavy rain, this causes a major capacity issue in the wastewater network, causing overflow from manholes.
It leads to situations, like last September, where the stormwater network had to be released into the estuary to relieve pressure on the system, taking wastewater with it.
Common ways that people pollute the estuary are by emptying paint, oil and rubbish down the drains, or washing vehicles on concrete, Burton said.
Just because something is natural does not mean it should be washed down the drains - lawn clippings and dirt can have a negative impact on the estuary as well.
Burton suggested putting your rubbish and recycling out on collection day, rather than the night before, because rubbish and recycling could blow into waterways in the wind.
Council attention is currently focused on researching the extent of the city's stormwater problem, to help find solutions.
10 things you can do to look after the estuary
Things other than rainfall should not go down stormwater drains
Use Napier's weekly kerbside rubbish collection, dispose of chemicals, oils and paints properly, wash vehicles on lawns or at a proper car-wash facility
Problem 2: Litter that is not disposed of properly will enter the stormwater system
Solution 2: Never put rubbish anywhere other than in a rubbish bin, pick up any litter you see
Problem 3: Sediment, grass clippings, sawdust, dirt, dust and leaves change the water quality
Solution 3: Have a plan to sweep up dirt and dust from hardstand areas before the rain comes to wash it all "away"
Problem 4: Rainfall on some properties is plumbed to the wastewater system
Solution 4: Check your plumbing at home to ensure that rain from your roof and hardstand goes to the stormwater system
Problem 5: Cigarettes contain chemicals that are harmful to the environment
Solution 5: Use a proper cigarette disposal area
Problem 6: Sometimes spills happen, and the council doesn't get told about them to enable a quick response
Solution 6: If you see unusual levels of pollution call the council on (06) 835 7579
Problem 7: Septic tanks can overflow or saturate the ground
Solution 7: Ensure, if you have a septic tank, that it is serviced and maintained frequently
Problem 8: Chemicals mix with water and travel to the estuary causing poisonous effects
Solution 8: Only put on enough fertiliser/spray to do the job, use other non-chemical methods of weed control and fertilising
Problem 9: Heavy metals can be washed off roofing materials by rainfall
Solution 9: Keep metal parts of buildings painted to avoid rusting, purchase inert roofing types when replacing your roof
Problem 10: Sometimes kerbside recycling items blow away on windy days or when collections have been delayed
Solution 10: Only put recycling out on collection day, put lighter recyclables at the bottom of your bins