APPENDIX G Queensland Recycled Water Guideline
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APPENDIX G Queensland Recycled Water Guideline - Queensland EPA, 2005 Queensland Water Quality Guidelines, 2006 Prepared by Environmental Protection Agency This document contains guidelines for the quality of waters of Queensland. It is consistent with and should be seen as an extension of the National Water Quality Management Strategy and the Australian and New Zealand Environment and Conservation Council (ANZECC) 2000 Guidelines for Fresh and Marine Water Quality. More Information For further information about the Queensland Water Quality Guidelines please contact: Environmental Science Division Environmental Protection Agency 160 Ann Street BRISBANE QLD 4000 Telephone: 3896 9245 Email: to [email protected] Copies of the Queensland Water Quality Guidelines are available at Naturally Queensland Information Centre at the above address and at the Environmental Protection Agency website www.epa.qld.gov.au. Disclaimer The contents of this document have been complied using a range of source materials, and whilst reasonable care has been taken in its compilation the Environmental Protection Agency holds no responsibility for any errors or omissions and shall not be liable for any consequences that may result from using the contents of this document. Cover Photos: Source Environmental Protection Agency, Department of Natural Resources, Mines and Water, Tourism Queensland Version 2, March 2006 © The State of Queensland, Environmental Protection Agency Queensland Water Quality Guidelines, 2006 2007 MINOR UPDATES to the QUEENSLAND WATER QUALITY GUIDELINES (2006) The following are minor updates (March 2007) to the Queensland Water Quality Guidelines 2006 prepared by the Environmental Protection Agency. This is the first round of updates to these guidelines. Southeast Region Table 2.5.1.1 (page 16) Mid estuarine waters, dissolved oxygen (DO), upper limit – change from 100% to 105% saturation Upper estuarine waters, DO, upper limit – change from 100% to 105% saturation Table 2.5.1.2 (page 18) Noosa River, mid estuarine waters, DO, upper limit – change from 100% to 105% saturation Noosa River, upper estuarine waters, DO, upper limit – change from 100% to 105% saturation Pumicestone Passage ‘outer’, enclosed coastal waters, turbidity – 20th, 50th, 80th percentile change from 23 – 4 – 6 NTU to 2 – 4 – 6 NTU (respectively) Central Region Table 2.5.2.1 (page 32) Enclosed coastal waters, DO, upper limit – change from 100% to 105% saturation Mid estuarine waters, DO, upper limit – change from 100% to 105% saturation Upper estuarine waters, DO, upper limit – change from 100% to 105% saturation Wet Tropics Region Table 2.5.3.1 (page 34) Enclosed coastal waters, DO, upper limit – change from 100% to 105% saturation Mid estuarine waters, DO, upper limit – change from 100 %to 105% saturation Mid estuary, tidal canals, constructed estuaries, marinas and boat harbours – use indicator values for these waters as per row 3 of table 2.5.3.1. Delete final row (row 8) Queensland Water Quality Guidelines, 2006 8.2 Appendix B: Water types for guidelines 8.2.2.3.4Middle estuary The middle-estuary water type covers the majority of the length of most estuaries. The middle estuary begins below the upper estuary, if present, or from below the freshwater/estuarine cutoff if there is no upper- estuarine zone. The mid-estuarine zone extends downstream to near the mouth of the estuary at the coast. It excludes the small section just up from and including the mouth that is well flushed each tide with incoming marine waters. The middle estuary has a moderate amount of water movement and salt and fresh water mixing. Upstream limit of middle estuary For long or poorly flushed estuaries with an upper estuarine zone, the top of the middle estuary is the lower limit of that upper estuarine zone (as outlined in section 8.2.2.3.3). For short or well-flushed estuaries, with no upper estuarine zone, the upper limit of the middle estuary is the upper limit of the whole estuary (as defined in section 8.2.2.3.2). Lower limit of middle estuary Selection of the various estuarine water types is primarily based on observed differences in water quality rather than specific physical attributes of estuaries. The advantage of this is that the water types reflect real (rather than presumed) differences in water quality. The disadvantage is that in the absence of a specific physical attribute, definition of the boundaries between water types is more complex. The lower limit of the middle estuary is essentially a boundary between estuarine waters that have a significant residence time within the estuary and those waters near the mouth of the estuary that are rapidly exchanged with adjacent coastal waters. It is the degree and rapidity of exchange between the estuary and the marine dominated coastal waters that is the principal driver of differences in water quality. The influence of freshwater inflows on the estuary is also a factor in that these have more impact in the main body of the estuary than in the well flushed areas near the mouth of the estuary. The most direct and appropriate way to define such a boundary would be on the basis of hydrodynamic modelling of the exchange between coastal and estuary waters. However, in most situations, such models are not available and therefore surrogate approaches are required. One such approach is the use of a salinity boundary. This is based on the premise that estuarine waters are influenced more by freshwater inflows than coastal waters. Thus, a boundary between the middle estuary and enclosed coastal/lower-estuarine waters can be based on the frequency with which salinity falls below normal seawater values. A review of EPA data indicates that for estuaries that discharge directly to open coastal waters, a reasonable boundary can be base on the following salinity rules: • Mid estuarine waters – salinity equivalent to full marine salinity (approximately 34–36 parts per thousand; or an electrical conductivity of approximately 52–54 mS/cm) for <20% of the time • Enclosed coastal/lower-estuarine waters – salinity equivalent to full marine salinity (approximately 34–36 parts per thousand; or an electrical conductivity of approximately 52–54 mS/cm) for >20% of the time Where estuaries flow into coastal water bodies that do not have fully marine salinities; for example, narrow straits or enclosed bays the salinity cut-off may actually occur below the mouth of the main estuary channel, out in the coastal water zone. However, although the salinity-based boundary is a useful guide, it should not completely override common sense assessments of the extent of mixing and flushing. For example, in some estuaries, where there is Queensland Water Quality Guidelines, 2006 limited freshwater inflow, the salinity boundary may be located some way up the main estuary channel where mixing would obviously be quite limited. Another situation is where an estuary flows into a series of narrow enclosed channels which may have high levels of salinity but which are still themselves poorly flushed and are more estuarine than coastal in nature. In these situations, some amendment of the water type boundary (see next paragraph) is acceptable. As rules of thumb, in most estuaries, the enclosed coastal/lower-estuarine zone would not extend further than 5km up the main estuary channel regardless of the salinity. In small estuaries or those with significant natural barriers near the mouth (e.g. a well developed bar) the boundary would be closer to the estuary mouth. In very long estuaries with large tidal flows, the boundary might extend a few kilometres further up than 5km. In estuaries flowing into very enclosed coastal waters, the boundary may be set beyond the mouth of the main estuary channel. Tributaries entering the middle estuary For these guidelines, any estuarine sections of tributaries that drain into a mid-estuarine zone of the main estuary channel are themselves defined as mid-estuarine. The criteria for deciding the estuarine/freshwater cutoff in these tributaries are the same as those outlined in section 8.2.2.3.2 above. Some tributaries of the main estuary channel may also have an upper-estuarine zone. The criteria for deciding whether there is an estuary, and where the mid-estuarine/upper estuarine cutoff lies, are the same as those outlined in section 8.2.2.3.3 above. The length of the estuarine section of such tributaries is the distance from the mouth at the main estuary channel to the estuarine/freshwater cutoff. Tidal canals, constructed estuaries, marinas and boat harbours For these guidelines tidal canals, constructed estuaries, marinas and boat harbours have water quality characteristics in common with the corresponding mid-estuary waters. More information For further information on these updates or the Queensland Water Quality Guidelines contact:; Director Freshwater and Marine Sciences Environmental Science Division Environmental Protection Agency Phone (07) 3896 9244 Queensland Water Quality Guidelines, 2006 Foreword Queensland’s diverse waters range from ephemeral inland streams to the great tidal rivers of the Wet Tropics. The state has a myriad of estuaries, wetlands, coastal bays and the World Heritage waters of the Great Barrier Reef. All of these waters support diverse and essential ecosystems, but are, at the same time, subject to ever-increasing pressure to accommodate the state’s human population. With Queensland continuing to be the fastest-growing state in Australia, protecting the quality of the state’s waters in the face of such growth is a major priority for the Queensland Government. National Guidelines for water quality were published in 2000. These set benchmark values against which the quality of waters can be assessed. They also provide the technical base for management objectives for waters. It is difficult for a national document to cover the vast range of water types found in Australia and the national guidelines themselves recommend developing more regionally specific guidelines.