Bingham Road Creek wetland
2330. Hon Alison Xamon to the Minister for Environment
I refer to the Bingham Rd Creek artificial wetland, and ask —
(1) I quote the Minister’s press release from 22 April 2010, where she states,’The Ellen Brook Catchment provides only seven percent of the Swan River’s annual flow but it produces 37 percent of the river’s phosphorus load and 10 percent of its nitrogen load’ —
(a) what is the area of the Bingham Road Creek drainage basin; and
(b) what is the area of its catchment?
(2) How many drainage basins or sumps are present in the catchment of the Ellen Brook?
(3) How many conservation category wetlands, resource enhancement wetlands and multiple use wetlands are present in the catchment of Ellen Brook?
(4) How many hectares of conservation category, resource enhancement and multiple use wetlands have been cleared, drained or filled in the years —
(a) 2004;
(b) 2005;
(c) 2006;
(d) 2007;
(e) 2008;
(f) 2009; and
(g) 2010 to date?
(5) How much has it cost to design, plan, consult and construct the Bingham Road Creek artificial wetland?
(6) What is the current nutrient load of phosphorus and nitrogen entering the Bingham Road Creek artificial wetland?
(7) What are the sources of this nutrient pollution?
(8) How many tonnes of highly soluble phosphorus and nitrogen fertilisers are spread within the catchment of the Bingham Rd Creek artificial wetland?
(9) How many tonnes of low solubility phosphorus and nitrogen fertilisers are spread within the catchment of the Bingham Road Creek artificial wetland?
(10) What are the designed performance targets for the efficiency of the artificial wetland?
(11) How many pollution prevention notices, particularly relating to illegal and/or unlicensed discharge to drains, watercourses or groundwater, have been issued by the Department of Environment and Conservation (DEC)/SRT in response to pollution in the Ellen Brook catchment for the years —
(a) 2005-06;
(b) 2006-07;
(c) 2007-08;
(d) 2008-09 and;
(e) 2009 to 23 March 2010?
(12) How many pollution prevention notices, particularly relating to illegal discharge to drains, watercourses or groundwater, have been issued by the DEC/SRT in response to pollution in the Ellen Brook catchment for the years —
(a) 2005-06;
(b) 2006-07;
(c) 2007-08;
(d) 2008-09 and;
(e) 2009 to 23 March 2010?
(13) How many prosecutions have been commenced under sections 49, 50, 50A and /or 50B of the Environmental Protection Act 1986, have been commenced by the DEC/SRT in response to pollution in the Ellen Brook catchment for the years —
(a) 2005-06;
(b) 2006-07;
(c) 2007-08;
(d) 2008-09 and;
(e) 2009 to 23 March 2010?
(14) How many pollution monitoring stations are located upstream in the catchment of Bingham Road Creek drainage basin?
(15) What has been the monitoring trend, regarding the detected levels of nutrients, heavy metals and organicides within surface water, groundwater and soils within the Bingham Road Creek drainage basin, over period 2005 to 2010?
(16) What are the expected contaminants to be found in the Bingham Road Creek drainage basin sediments in —
(a) forms;
(b) volumes; and
(c) concentrations?
(17) How is it proposed that these contaminated sediments will be transported to an appropriate waste control facility?
(18) Have additional costs for contaminated wastes been included in the estimate of costs for the project?
(19) If yes to (18), what are the specific excavation, transfer, transport and containment costs for the contaminated waste sediment?
(20) What are the likely sources of contaminants in the drainage catchment and groundwater leading to the Bingham Road Creek drainage basin?
(21) What education and awareness campaigns are being specifically targeted at industrial, residential, commercial and rural property owners and tenants within the catchment of the Bingham Road Creek drainage basin?
(22) What are the likely and desired educational and awareness outcomes from such campaigns?
(23) What are the likely and desired environmental outcomes from such campaigns?
(24) Have any additional funds been sought from industrial, residential, commercial and rural property owners and tenants upstream of the Ellen Brook drainage basin in order to fund engineering works and ongoing monitoring and compliance?
(25) What is the intended reduction in nutrient, heavy metals and organicide concentrations between receiving water and discharge into the drainage channel, and therefore back into the Swan River?
(26) What is the intended reduction in nutrient, heavy metals and organicide concentrations between receiving water, and discharge water into the superficial aquifer and therefore into deeper Gnangara Mound aquifers?
(27) What is the engineering lifespan of the artificial wetland before needing extensive reengineering?
(28) What is the expected buffering capacity of soils and flora plantings in the Bingham Road Creek drainage basin particularly to maintain expected reductions in nutrients, heavy metals and organicides over the next —
(a) ten years; and
(b) twenty years?
(29) What is the operational lifespan of the artificial wetland?
(30) How often will the Bingham Road Creek drainage basin be dredged to remove detained nutrients, heavy metals and organicides over the next twenty years?
(31) Which decision making Agency will be responsible for ongoing maintenance of the Bingham Road Creek drainage basin?
(32) Are they sufficiently funded and indexed over the long-term to ensure intended pollution mitigation over the expected operational lifespan of the artificial wetland?
(33) Are all residential, commercial, industrial and rural properties within the catchment of the Bingham Road Creek drainage basin completely and operationally connected to the Water Corporation deep sewerage system?
(34) If no to (33) —
(a) is the Minister for the Environment working with the Minister for Water to ensure that groundwater and surface water contamination from septic tanks and leach drains in the Anvil Road drainage basin catchment will be limited in the short term; and
(b) what is the desired timetable for the Department of Environment and Conservation to ensure sewerage connections within the Anvil Road drainage basin catchment are made to all residential, commercial and industrial properties, and thus remove a major continuing source of groundwater and surface water contamination?
Hon DONNA FARAGHER replied:
(1) (a) The Bingham Road Creek wetland is 5,500m².
(b) The catchment area of Bingham Road Creek is 12.95km². This is located in the Ellen Brook Catchment that has an area of 715km².
(2) The number of drainage basins or sumps in the Ellen Brook catchment is currently unknown and would take a significant amount of investigation to determine.
(3) The Department of Environment and Conservation's (DEC) Geomorphic Wetlands Swan Coastal Plain Dataset records wetland area and assigned management categories for mapped wetland areas, rather than estimates of numbers of individual wetlands. The area of mapped wetlands in the Ellen Brook catchment as of May 2010 by management category is:
a) Conservation category — 1,883 hectares
b) Resource enhancement — 1,135 hectares
c) Multiple use — 15,092 hectares.
(4) (a-g) Records for changes in wetland management categories in the wetlands dataset have only been maintained by DEC since taking over the previous Department of Water database in June 2008. DEC has not recorded any changes to the areas of wetland management categories within the Ellen Brook catchment since that date.
(5) Site investigations, aboriginal consultation and monitoring during construction, designs, construction and revegetation cost approximately $297,000.
(6) The current load of total phosphorus and total nitrogen entering the Bingham Road Creek Wetland is estimated at 340 kg and 1 tonne per year, respectively.
(7) The sources of nutrient pollution in the Bingham Road Creek catchment are predominantly from rural land uses such as cattle grazing, but also influenced by animal keeping (mainly horses), intensive horticulture and residential dwellings.
(8) The amount of highly soluble phosphate and nitrogen fertilisers applied in the Bingham Road Creek catchment is unknown.
(9) The amount of low solubility phosphate fertilisers applied in the Bingham Road Creek catchment is unknown though it should be noted that that these types of fertilisers are not commercially available for agriculture or horticultural use. Trials are underway to assess the efficacy of these fertilisers.
(10) Modelled nutrient removal efficiency of the Bingham Road Creek Wetland is 37% or 128kg for total phosphorus, 1.9% or 19kg for total nitrogen and 66-99% or 837kg for total suspended solids per year.
(11) (a-d) Nil.
(e) No pollution prevention notices were issued, however, one letter of warning was issued regarding an unauthorised discharge.
(12) (a-d) Nil.
(e) See the answer to 11(e).
(13) (a-e) Nil.
(14) There are two monitoring sites upstream of the Bingham Road Creek Wetland. One site is a Ribbons of Blue registered site and the other is a site established by the Swan River Trust, Department of Water and Ellen Brockman Integrated Catchment Group to monitor water quality trends leading into the wetland and ultimately to monitor the efficiency of the wetland system in removing nutrients.
(15) Monitoring trends of nutrients in surface water has been relatively stable between 2005 and 2010. Average total phosphorus concentrations leading into the wetland are approximately 0.9mg/L whilst average total nitrogen concentrations are approximately 2.5mg/L. Healthy Rivers Action Plan Interim targets for total phosphorus and total nitrogen are 0.1mg/L and 1.0mg/L respectively. Heavy metals and organicides have not been sampled in surface water of the catchment.
Soil samples taken from the Bingham Road Creek site in 2008 during site investigations showed heavy metal levels below ANZECC Assessment levels for soil (ANZECC and ARMCANZ, 2000) where guideline values were available. Nutrients were also sampled and were below ANZECC Assessment levels for soil where guideline levels were available. Organicides have not been sampled in soil of the catchment.
There is no nutrient, metals or organicide ground water data for the Bingham Road Creek Catchment between 2005 and 2010.
(16) (a)-(c) On the basis that the term contaminants refers to heavy metals and organicides referred to in the previous question, and given the known water quality and soil data available for the site and the fact it exists on a natural waterway, no contaminants above guideline levels are expected to be found in the sediments at the site.
(17) Sediment collected in the wetland is unlikely to be contaminated due to the catchment being dominated by rural landuses, however any sediments required to be removed from the wetland will be sampled and analysed before removal as per the maintenance plan.
(18) The site does not contain contaminated wastes and as such does not require additional funds for their removal.
(19) Not applicable.
(20) Possible sources of contaminant in the basin may come from rural landuses. Though not considered to be contaminants, nutrients and sediment (mainly sand) are expected to accumulate at the site.
(21) Education and awareness programs running in the Ellen Brook Catchment target small and large rural landholders as well as urban landholders to reduce nutrient use and runoff. Programs include Heavenly Hectares and Great Gardens workshops. Industrial and commercial landuses are not located in the Bingham Road Creek Catchment.
(22) Expected outcomes of the programs are to improve fertiliser management, provide a better understanding of consequences of excessive nutrients entering waterways and provide better planning to improve production on farms.
(23) Likely and desired environmental outcomes of the programs are reduced loads of nutrients entering the Ellen Brook and subsequently the Swan River and enhancing sustainable farming practices.
(24) No. This is not considered appropriate for a rural catchment with many different sources.
(25) It is expected that the Bingham Road Creek Wetland will reduce the total phosphorus load, the total nitrogen load and total load of suspended solids entering the Ellen Brook by 128kg, 19kg and 837kg respectively. As the project is focused on reducing nutrients, expected reductions in heavy metals and organicides have not been modelled.
(26) Expected reduction of nutrients, metals and organicides between receiving waters and discharge into the superficial aquifer are unknown.
(27) Based on the maintenance plan and assuming there are no major changes to catchment landuse and resultant water quality, the lifespan of the wetland could be at least 80 years.
(28) (a-b) A specific buffering capacity figure cannot be provided for soils and flora. Regular monitoring planned to be undertaken on the wetland will assist in understanding these buffering capacities.
(29) The lifespan of the wetland could be at least 80 years.
(30) It is not expected that the wetland will need to be dredged at all during the life of the project. Sediment will need to be removed from a designated sedimentation area through regular maintenance. Given that modelling suggests that 837kg (or approximately 1m³) of total suspended solids will be detained at the site per year and the volume of the wetland is 3850m³, it is expected that sediment removal will be required once or twice in the next 20 years.
(31) As the Bingham Road Creek site is located on Department of Defence owned land, they will be responsible for the maintenance of the physical structures such as bunds, spillway and sediment/refuse removal. The Ellen Brockman Integrated Catchment Group (EBICG) is responsible for maintenance of weeds and revegetation on the site over the next 5 years. The EBICG is supported through funding allocated by the Swan River Trust.
(32) Department of Defence and EBICG have agreed to maintain the site. Funding has been provided by the Trust to cover the first 5 years of maintenance, indexed to allow for inflation.
(33)-(34)None of the properties within the catchment of the Bingham Road Creek Wetland are connected to the Water Corporation deep sewerage system as it is not available.
The State Government is committed to implementing the Swan Canning Water Quality Improvement Plan and has already invested $3.29 million in its implementation. I refer the Member to the Minister for Water on matters regarding deep sewerage.