In 2017 Wairarapa conservationist and trout fisherman the late Bill Benfield wrote a book titled “Water Quality and Ownership” in which he said the much vaunted riparian strips failed to deal with the big real problem.
“The fad of fencing rivers has been a ‘knee jerk’ response to Fish and Games’ accusations of “dirty dairying,” he said.
Bill Benfield said the policy of riparian strips was well intentioned but failed to fully address the problem of nitrate run-off and leaching.
“Logically the problem is one of the total catchment, i.e. watershed management, not just a five or ten metre strips beside streams.”
There other factors that could be damaging to river and stream ecology. After all, trout and salmon are part of the freshwater ecosystem.
One was the widespread use of damaging chemicals such as diazinon, DDT’s replacement, for combating grass grub. It was ratted as “a clear threat to aquatic ecosystems.” Never mentioned by Fish and Game was the silt and debris-laden run-off from clear-felled commercial pinus radiata plantations.
“Fencing off streams was more a public relations reaction, to Fish and Game’s single-focus “dirty dairy” campaign. It is a text book example of a Clayton’s solution – how to maintain intensive agriculture and its serious degradation of rivers while avoiding the causes. As an added public sweetener, the fenced off river margins were planted with natives. Fish and Game naively jumped on the band wagon.”
Bill Benfield said in the end, the Fish and Game “dirty dairying” campaign did nothing to stop the huge expansion of dairying, particularly in low rainfall regions like Canterbury and the MacKenzie Basin.
Fish and Game had unfairly ignored other major polluters such as urban centres discharging partially treated sewerage and untreated storm water into rivers and ill effects from agricultural chemicals such as diaznon and siltation from clear felling forestry blocks.
Many farmers felt they had been solely picked upon when urban discharges were ignored by Fish and Game. In some cases, farmers had consequently refused anglers permission for access.
“But then you’ve got no access through the hedge of blackberry, willows and other vegetation that grew on the riparian strips.”
From an anglers’ viewpoint practical access to the stream became blocked, as riparian strips quickly became overgrown with weeds like blackberry, broom, gorse and even the poisonous tutu.
The river becomes inaccessible for trout fishing while doing nothing to stop most pollution from entering the waterways.
What was needed is a more focused system of river management. There was certainly a case that where there is no intensive dairying, river banks can be managed in a natural unfenced condition.
“Stock, like sheep, goats and horses are not a major problem with minimal impact on banks and well within the healthy life of the river, with its cycles of high and low flows. Cattle can be a different issue; it is an issue of density and a matter of finding a reasonable level at which agriculture can co-exist with the river,” said Bill Benfield.
Where cattle densities were high and stock received supplementary feed, they should be excluded from the river. If mixed stock are grazed, i.e. sheep and cattle, then the “selecta-fence” can be the answer – two top wires to stop cattle and no bottom wires to let sheep through.
“As an example of corporate posturing, fencing rivers has been a stunning success. As a solution it has been a failure,” summarised Bill Benfield.