Wairarapa's major river polluted

Wairarapa's major waterway, the Ruamahanga River, is far from pristine with sections of it being as heavily polluted as the Manawatu River, one of the worst in the country.
In a briefing paper to be put before a committee of Greater Wellington Regional Council today researcher Leila Chrystall, who has written a university thesis on the river and its catchment, has found water quality in the Ruamahanga is only "marginally better" than the Manawatu River even though the Manawatu waterway drains a much more heavily populated catchment.
This she directly attributes to climate and "human demands".
Over the past 10 years sheep and beef farming in the Ruamahanga catchment has been replaced with dairy farming and land use intensification has brought about a huge increase in the demand for water.
Ms Chrystall said some surface water management zones are near full allocation and several groundwater sub-zones are fully allocated.
Tributaries on the western side are cleaner than those on the east.
"Two central tributaries the Mangatarere River and the Parkvale Stream have very poor water quality."
She said on its southward journey the river's water quality deteriorates soon after it moves out of the forested land near Mt Bruce, into pastoral land.
Nutrients from farming increases, water clarity worsens and there is a higher incidence of e.coli.
"This deterioration is noticeable before the river reaches Masterton, and the first major discharge of municipal effluent."
Ms Chrystall said between the river's monitoring sites at Te Ore Ore and Gladstone there is a sharp increase in the amount of dissolved reactive phosphorus.
"More than three-quarters of the DRP load increase is likely to have been generated from the Masterton sewage treatment plant, with the remaining quarter coming from direct land run-off."
Downstream from Gladstone nutrient loads continue to increase with town effluent from Carterton, Greytown, Featherston and Martinborough entering the river.
Ms Chrystall said run-off from farming land, unfenced waterways and "point discharges" from farms and industry all contribute to the state of rivers, and impact on groundwater quality.
Many aquifers, particularly around Masterton and Martinborough, are contaminated.
Ms Chrystall said water quality in Lake Wairarapa is poor and unlikely to improve with current land use and projected land use intensification around its shores.
"Since the lake is effectively an artificial system, the lake has been unable to flush itself.
"This has caused some concern in the local community, including iwi.
'Tangata whenua are also deeply concerned over continued discharge of human sewage into waterways.
"Not only is it diminishing the quality of the waterways, it is also extreme offensive."
Ms Chrystall said bad water quality impacts on the river's recreational and aesthetic values.
Three sites along the river the Cliffs, Kokotau and Waihenga had reached an "alert" level for swimming water quality several times in a previous summer and six of seven swimming places on the river had been graded as "very poor".