Swan River - nutrient pollution
2337. Hon Alison Xamon to the Minister for Environment
I refer to nutrient pollution in the Swan River, and ask —
(1) How many tonnes of nitrogen and phosphorus enter the Swan and Canning River waterways each year from rural sources?
(2) How many tonnes of nitrogen and phosphorus enter the Swan and Canning River waterways each year from metropolitan sources?
(3) What is the Government doing to strongly reduce rural fertiliser inputs into the Swan?
Hon DONNA FARAGHER replied:
(1) Existing data does not provide an explicit distinction between rural and metropolitan sources of nitrogen and phosphorus.
Based on the average annual load for the period 1997-2006, 101.3 tonnes of total nitrogen and 11.8 tonnes of total phosphorus enter the Swan and Canning rivers each year from sources in predominantly rural catchments. In addition, 67.3 tonnes of total nitrogen and 7.3 tonnes of total phosphorus enter the rivers each year from sources in predominantly semi-rural catchments. These loads are for the coastal catchments of the Swan and Canning rivers and do not include the AvonRiverthat contributes on average a further 575 tonnes of total nitrogen and 20 tonnes of total phosphorus each year.
(2) Based on the average annual load for the period 1997-2006, 82.3 tonnes of total nitrogen and 6.78 tonnes of total phosphorus enter the rivers each year from sources in predominantly metropolitan (urban) catchments.
(3) The State Government is encouraging farmers and commercial users to adopt best management fertiliser practice through the Fertiliser Industry Federation of Australia's Fertcare Program. To date, the State Government has invested $1.1 million into trials to assess the efficacy of low water soluble phosphorus fertilisers and to continue best practice fertiliser management demonstrations for grazing and horticultural sectors. The State Government is also funding research and trials into the viability of using soil amendments to help prevent phosphorus loss from the land.