Table 2.9.1 Resource status and trend summary of nutrient export (P) in selected catchments Catchment/system Summary Hazard Trend Confidence in Confidence in system risk impact of trend number agriculture 1 Swan–Canning System High Variable Adequate Limited evidence The main sources of nutrients are agriculture, quality evidence and or limited predominantly from cattle grazing in the high level of consensus Ellenbrook sub-catchment, and urbanisation. consensus 2 Peel–Harvey System The main source of P is agriculture, Very high Variable Adequate Limited evidence particularly from broadacre dryland grazing of quality evidence and or limited cattle. The estuary condition has improved high trial of consensus with the construction of the Dawesville consensus Channel; however, trial blooms and fish kills now occur in the lower reaches of major rivers. 3 Leschenault Catchment The main nutrient losses originate from diffuse High Variable Adequate Limited evidence sources, including broadacre beef and dairy quality evidence and or limited grazing and dairy sheds near streams. All high level of consensus monitored sites in the estuary and catchment consensus exceed target levels. 4 Vasse–Geographe Most of the nutrient loads come from High Variable Adequate Limited evidence Catchment broadacre grazing of beef and dairy cattle. quality evidence and or limited Upstream tributaries and wetlands have poor high of consensus water quality. consensus 5 Scott River Catchment Agricultural land use is changing from dryland Moderate Variable Adequate Limited evidence grazing to more intense irrigated quality evidence and or limited enterprises, resulting in an increasing nutrient high level of consensus impact. consensus 6 Wilson Inlet Catchment The main diffuse sources of nutrients are beef Insufficient Variable Evidence and Evidence and and sheep grazing with broadacre cropping. data for full consensus too low to consensus too low Phosphorus concentrations in tributaries are assessment make an assessment to make an increasing. assessment 7 Oyster Harbour Insufficient Variable Evidence and Evidence and Most of the nutrient come from diffuse Catchment data for full consensus too low to consensus too low agricultural sources in higher rainfall areas assessment make an assessment to make an supporting grazing enterprises. assessment
Table 2.9.1 Resource status and trend summary of nutrient export (P) in selected catchments number Catchment/system Summary Hazard Trend Confidence in risk impact of agriculture Confidence in trend 1 Swan–Canning System The main sources of nutrients are agriculture, predominantly from cattle grazing in the Ellenbrook sub-catchment, and urbanisation. High Variable Adequate evidence and high level of consensus Limited evidence or limited consensus 2 Peel–Harvey System The main source of P is agriculture, particularly from broadacre dryland grazing of cattle. The estuary condition has improved with the construction of the Dawesville Channel; however, blooms and fish kills now occur in the lower reaches of major rivers. Very high Variable Adequate evidence and high of consensus Limited evidence or limited consensus 3 Leschenault Catchment The main nutrient losses originate from diffuse sources, including broadacre beef and dairy grazing and dairy sheds near streams. All monitored sites in the estuary and catchment exceed target levels. High Variable Adequate evidence and high level of consensus Limited evidence or limited consensus 4 Vasse–Geographe Catchment Most of the nutrient loads come from broadacre grazing of beef and dairy cattle. Upstream tributaries and wetlands have poor water quality. High Variable Adequate evidence and high of consensus Limited evidence or limited consensus 5 Scott River Catchment Agricultural land use is changing from dryland grazing to more intense irrigated enterprises, resulting in an increasing nutrient impact. Moderate Variable Adequate evidence and high level of consensus Limited evidence or limited consensus 6 Wilson Inlet Catchment The main diffuse sources of nutrients are beef and sheep grazing with broadacre cropping. Phosphorus concentrations in tributaries are increasing. Insufficient data for full assessment Variable Evidence and consensus too low to make an assessment Evidence and consensus too low to make an assessment 7 Oyster Harbour Catchment Most of the nutrient come from diffuse agricultural sources in higher rainfall areas supporting grazing enterprises. Insufficient data for full assessment Variable Evidence and consensus too low to make an assessment Evidence and consensus too low to make an assessment quality quality quality quality quality trial system trial
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