Overview of Catchment Nutrient Reports

The Department of Water publishes a series of nutrient reports for the Peel-Harvey catchment.
The Peel-Harvey catchment has been divided into 13 subcatchments organised around a network of waterways draining into the Peel-Harvey Estuary with a nutrient report prepared for each. Enrichment of the estuary in nutrients (eutrophication) can result in algal blooms, increased growth of aquatic weeds and fish kills. The intent of these reports was to summarise the information gathered during the long-term water quality monitoring programs, capture other information including land use and soil type and to compare and prioritise subcatchments for remediation to reduce the amount of nutrients (the load) exported to the estuary.

Each report is a four-page document that:
• summarises the geographical setting of the subcatchment, describes the general soil type, and, where known, the risk of leaching nutrients from the soils,
• classifies and quantifies the various land uses e.g. cattle for beef, mixed grazing, horticulture
• summarises the information collected from the long-term water quality and flow monitoring programs carried out from 1996 to 2009,
• provides other relevant information and observations where available including fish kill events, algal blooms, estuarine nutrient concentrations and rainfall, and
• provides estimates of the total loads of nutrients delivered to the Peel-Harvey Estuary from the subcatchment, from mathematical modelling of the nutrient flow using the Streamflow Quality Affecting Rivers and Estuaries (SQUARE) model.
The reports present a Nutrient Summary showing median annual total phosphorus (TP) and total nitrogen (TN) concentrations determined from the monitoring programs. From these the status of the subcatchment, determined over a period of at least three years, is classified as Low, Moderate, High or Very high with respect to each contaminant. Only three subcatchments, Mayfield Drain, mid-Murray and South Dandalup were classified as “Low” for either or both TP and TN.
Loads calculated from flow-gauging station measurements are also presented. Monthly TN and TP measurements are also compared against the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ 2000), with most of the subcatchments exceeding the guideline values for both TN and/or TP on many of the sampling occasions. Trends in the measured concentrations during the period 2005-2009 are also examined.
The seasonal variations in average concentrations of TN and TP and the various component forms (e.g. nitrate, ammonium, soluble reactive phosphorus) are also shown. The concentrations of in-stream nutrients generally increase with the first flush of rainfall, but other factors including dilution, concentration by evaporation, release from sediments and groundwater discharges make interpretation of these data difficult to summarise at a whole-of-catchment scale.
The SQUARE model draws together and quantifies various information sources for each sub-catchment to estimate flows and loads of nutrients to the Peel-Harvey Estuary. The reports show the annual exports of TN and TP to the estuary for each subcatchment and the proportions of the total nutrient loads attributed to various land uses estimated by SQUARE. The TN and TP loads for all subcatchments are shown allowing comparison of the contribution of each to the estuary. Based on these loads, each subcatchment is categorised into High, Medium or Low priority for remediation action. The High priority subcatchments for nitrogen remediation are Dirk Brook; Punrak Drain; Lower Murray, Mid-Murray and Dandalup (aggregated into a single catchment); and Harvey. High priority catchments for phosphorus are Punrak Drain; Coolup; Harvey and Meredith Drain. In each case the nutrient load is dominated by the Cattle for beef land use.
Catchment Nutrient Reports Peel-Harvey 2011 Update
In 2011, trend analyses were performed on the TN and TP concentrations measured from 2005 to 2009 in each of the 13 subcatchments. The results of these analyses are represented graphically on maps of the catchment, along with the status of each subcatchment classified Low, Moderate, High and Very high with respect to TN and TP concentrations as described above. An increasing trend in the TN concentrations was observed in the Samson North catchment, with emerging increasing trends in the Nambeelup Brook, Mayfield Drain, Meredith Drain and Peel Main Drain subcatchments. With the exception of Mayfield Drain (Low) all of these subcatchments are classified as High or Very high with respect to TN concentration. No trend was apparent in the nine other subcatchments.
Emerging increasing trends in TP concentration were observed in the Peel Main Drain (High), Middle Murray River, Mayfield Drain (Moderate) and Samson North (High) subcatchments. Conversely, emerging decreasing trends were observed in the Lower Serpentine (Very High), Nambeelup Brook (Very High) and South Dandalup (Moderate) subcatchments with an emerging decreasing trend in TP in the Dirk Brook – Punrak Drain (High) subcatchment. No trend was observed in the other 5 subcatchments.

Catchment Nutrient Reports Peel-Harvey 2012, 2013 and 2014 Updates
Updates of the 2010 nutrient reports to include more recent information are now also available on the Peel-Harvey Catchment Council website. The single-page 2012, 2013 and 2014 reports provide, where available, the median concentrations and loads of TN and TP for the intervening years 2010 and 2011, 2012 and 2013 respectively. The status of each subcatchment is also updated accordingly.

Future Updates

The 2015 Nutrient reports have not yet been published. The format of these will closely resemble that of the 2010 reports but include a summary of the data collected to the end of 2014. In addition, trends in TN and TP concentrations measured from 2010 to 2014 will be presented, similar to the 2011 updates.

Catchment Nutrient Reports Peel-Harvey 2014 Update

Dirk Brook 2014 Update
Drakes Brook Waroona Drain 2014 Update
Harvey River 2014 Update
Lower Serpentine 2014 Update
Mayfield 2014 Update
Meredith Drain 2014 Update
Mid Murray 2014 Update
Nambeelup Brook 2014 Update
Peel Main Drain 2014 Update
Samson North Drain 2014 Update
South Coolup 2014 Update
South Dandalup 2014 Update
Upper Serpentine 2014 Update

Catchment Nutrient Reports Peel-Harvey 2013 Update

Dirk Brook 2013 Update
Drakes Brook Waroona Drain 2013 Update
Harvey River 2013 Update
Lower Serpentine 2013 Update
Mayfield 2013 Update
Meredith Drain 2013 Update
Mid Murray 2013 Update
Nambeelup Brook 2013 Update
Peel Main Drain 2013 Update
Samson North Drain 2013 Update
South Coolup 2013 Update
South Dandalup 2013 Update
Upper Serpentine 2013 Update

Catchment Nutrient Reports Peel-Harvey 2012 Update

Dirk Brook 2012 Update
Drakes Brook Waroona Dam 2012 Update
Harvey River 2012 Update
Lower Serpentine Gull Rd 2012 Update
Mayfield Drain 2012 Update
Meredith Drain 2012 Update
Mid Murray 2012 Update
Nambeelup Brook 2012 Update
Peel Main Drain 2012 Update
Samson North Drain 2012 Update
South Coolup Drain 2012 Update
South Dandalup Drain 2012 Update
Upper Serpentine 2012 Update

Catchment Nutrient Reports Peel-Harvey 2011 Update

Peel-Harvey Catchment Locations 2009
Peel-Harvey TN Status Trend 2009
Peel-Harvey TP Status Trend 2009

Catchment Nutrient Reports Peel-Harvey 2010

Dirk Brook 2010
DrakesBrook Waroona Drain 2010
Harvey River 2010
Lower Serpentine 2010
Mayfield 2010
Meredith Drain 2010
Mid Murray 2010
Nambeelup Brook 2010
Peel Main Drain 2010
Samson North Drain 2010
South Coolup 2010
South Dandalup 2010
Upper Serpentine 2010


Other Reports

Auditor General’s Report – Management of Ramsar Wetlands in Western Australia
Changes in Peripheral Vegetation of the Peel-Harvey Estuary 1994-1998
Collaborative Management of the Peel-Yalgorup System
Guideline for the Determination of Wetland Buffer Requirements
Guidance for the Assessment of Environmental Factors – Protection of the Lake Clifton Catchment
Information Sheet on Ramsar Wetlands (RIS)
Littoral Vegetation Monitoring of the Peel-Yalgorup Ramsar Site 2008
Peel-Ramsar Lakes Case Study 2013
Peel-Yalgorup Ramsar Wetlands Monitoring: Littoral & Fringing Vegetation Mapping – March 2009
Peel-Yalgorup Ramsar Littoral & Fringing Vegetation Monitoring: Review – Final Report, June 2010
Peel-Yalgorup System: Assessment against Ramsar Criteria
Peel-Yalgorup System brochure with map
Peel-Yalgorup System Banner
Peel-Yalgorup Thrombolite Banner
Ramsar Roadside Banner
Ramsar – List of Wetlands of International Importance – 22 August 2012
Ramsar Sites in Order of their Addition to the Ramsar List of Wetlands of International Importance