Stratford Coal Pty Ltd Stratford Coal Mine PLANS Annual Environmental Management Report June 2010

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2 Stratford Coal Pty Ltd Stratford Coal Mine PLANS Annual Environmental Management Report June 2010

3 Stratford Coal Pty Ltd Stratford Coal Mine APPENDIX I AMENDED OR NEW APPROVAL AND LICENCE CONDITIONS ISSUED DURING THE REPORTING PERIOD Annual Environmental Management Report June 2010

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30 Stratford Coal Pty Ltd Stratford Coal Mine APPENDIX II ENVIRONMENTAL MONITORING DATA Annual Environmental Management Report June 2010

31 Stratford Coal Pty Ltd Stratford Coal Mine AIR QUALITY Annual Environmental Management Report June 2010

32 D7 - March/April - possible bird dung.

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37 Stratford Coal Pty Ltd Stratford Coal Mine BIOLOGICAL MONITORING Annual Environmental Management Report June 2010

38 Biological Monitoring Of the Stratford (Bowen Road North) Coal Mine Study 3, Survey 7, October INVERTEBRATE IDENTIFICATION AUSTRALASIA 51 Panorama Parade, Panania, NSW 2213, Phone (02)

39 Table of Contents Executive Summary...3 Introduction...4 Study area and sampling sites...4 Methodology...7 Macroinvertebrate Sampling...7 Identification...7 Data analysis...7 Silt Tolerant Species...8 Physico-Chemical Data...8 Results...8 Environmental Physico-chemical Conditions...8 Ecological Response - Macroinvertebrate Data...13 Discussion...17 Acknowledgements...19 References

40 Executive Summary This is the seventh report commissioned by Stratford Coal Pty Ltd as part of the environmental monitoring program for the Bowens Road North Coal Mine. This mine is located on the north side of the now completed Stratford Coal Mine. Over the last twelve months since the last survey in October 2008 (Study 3, Survey 6), average rainfall has lead to consistent low flow conditions with some periods of no flow. There was one high rainfall event in mid February that contributed to sustaining the river flow and therefore, ecosystem health. At the time of the survey, Avondale and Dog Trap Creeks and the Avon River were experiencing low flow conditions. This report provides the environmental assessment of the status of the aquatic ecosystems of Dog Trap and Avondale Creeks and the Avon River over the period October 2008 to October Six sites were sampled on the 8th of October 2009 for aquatic macroinvertebrates and water quality using rapid assessment techniques. Two sites are on the Avon River, one above (Site W1) and one below (Site W2) the confluence of the Avon River and Avondale Creek. Two sites are on Avondale Creek, (SiteW8) at Bowens Road, is directly downstream of the mining operation, while Site W3 on Dog Trap Creek is the control site. In addition one site monitors a dam discharge gully approximately 800 m below the discharge point. A total of 53 genera representing 38 families were observed. Four biological indices are used to determine the condition of the streams in and adjacent to the project area. The results of the current survey indicate that the overall aquatic biodiversity across all the sites are higher or equivalent to those of the previous survey. The environmental condition assessment has shown a significant increase for the Avon River and the Avondale Creek sites. These changes in ecosystem condition/health appear to be the direct result of continued moderate flow conditions in the Avon River and in the other creeks. 3

41 Introduction Stratford Coal Pty Ltd operates an open cut coal mine situated approximately 5 km SE. of Stratford and 17 km S. of Gloucester on the central coast of NSW. It has been in operation for the past 15 years. Until 2003 the operating coal mine was the Stratford Mine located to the southeast of the township of Stratford. This mine has now been exhausted and an open cut coal mine named the Bowens Road North Coal Mine is operating immediately to the north of and adjacent to the old Stratford Mine. As part of Stratford Coal's environmental monitoring program, Invertebrate Identification Australasia was commissioned to continue the biological monitoring of the streams in the area of the mine. This report presents the results of the seventh survey of the environmental monitoring program for Stratford Coal s Bowens Road North Coal Mine. The study examines the environmental condition of the aquatic ecosystems of the Avon River, Avondale Creek and Dog Trap Creek following a year of continued low flow conditions following previous increased conditions early in the year. Low rainfall in the months of August and September has lead to low flows up until October A combination of aquatic macroinvertebrate diversity and water quality parameters are ideally suited for the assessment of ecosystem health and conservation values of rivers, streams and ponds. The composition of the aquatic macroinvertebrate community reliably reflects both natural and threatening processes (i.e. with changes in the physico-chemical environmental parameters) operating within a catchment as they are the major contributors to the processing of energy through a catchment and are intrinsically linked to the water source. Their ubiquitous distribution and specific habitat requirements at the species and community level enables the use of their biodiversity as an indicator of ecological disturbance within the catchment. Study area and sampling sites Avondale Creek flows for 11 km to its junction with Dog Trap Creek, which then flows approximately 900m to the junction with the Avon River. Due to the close proximity of the new mine to the old mine the previous sampling sites are used to monitor the new mine and are described below. The six sample locations are listed in Table 1. Site code Site name and description Grid Reference S3 Dam discharge gully approximately 800m below discharge point '40"S '46"E W1 Avon River at Wenhams Cox Road '23"S '44"E W2 Avon River downstream of Site W '17"S '38"E W3 W5 W8 Dog Trap Creek near end of Wenhams Cox Road, a reference stream with its catchment used for grazing and forestry, with no mining. Avondale Creek at Wenhams Cox Road, downstream of the project area, at the freehold property boundary. Avondale Creek at Bowens Road, directly downstream of mining operations '32"S '30"E 32 06'33"S '40"E 32 07'29"S '45"E Table 1. Sampling sites. 4

42 Avondale Creek Sites S3, W5 and W8 Avondale Creek is a small meandering stream that passes through a mixture of heavily wooded forest in the surrounding escarpment and cleared, grazing country in the lower sections. Water quality varies substantially along the stream s gradient, with the upper escarpment sections having the best water quality. The lower sections of the stream, particularly in the area of Site W5 at Wenhams Cox Road, have very high natural salinity levels as a result of saline groundwater discharges. The salinity levels are inversely proportional to stream flow levels. The riverbed is characterised by a hard clay or bedrock base overlain by fine gravels, sand in the pools of the upper section of the stream through the mine operational area, to fine silts and clay with patches of gravel in the freehold property downstream of the mining area. Sites S3 and W5 were sampled for water quality and macroinvertebrates. Site W8 was not sampled as it was dry at the time of the survey. This site is an ephemeral reach and is often completely dry. Over the last 12 months Avondale Creek experienced periods of no flow or dry conditions during January, February, August, September and October During these the creek was reduced to a series of small pools at Sites W5 and S3. The water at all Avondale sites was clear with little or no suspended sediments and no algae. Site S3 is located in the dam discharge gully approximately 800m below the discharge point and feeds into Avondale Creek. The site is characterised by a dense native riparian zone, undisturbed stream banks, some macrophytes, substrate consisting of gravel and sand on a hard clay base and a small number of permanent pools. This is a relatively undisturbed environment. The stream at Site S3 had observed low flow at the time of sampling with all pools full with significant macrophyte communities established Site W5 viewed upstream (1); viewed downstream (2), taken October, Site W8 viewed upstream (3); viewed downstream (4), taken October,

43 5. 6. Site S3 viewed upstream (5), viewed downstream (6), taken October, The Avon River Site W1 and W2 The Avon River is a slow flowing river that flows along the western side of the project area. The riverbanks have a narrow riparian zone consisting of a mixture of native and introduced tree and shrub species. The surrounding catchment has largely been cleared, with cattle grazing being the main agricultural activity. The riffle zone of the riverbed is characterised by course gravel and cobble riffles on a hard clay base. The pool substrate is fine sand to silt. Water quality is moderate to high with low to moderate turbidity and nutrient levels. The current round of sampling at both Sites W1 and W2 had low levels of turbidity with no algae observed. Both sites were sampled for water quality and macroinvertebrates. During this survey both sites had low flow conditions. Significant macrophyte communities are becoming established at least within Site W1. A new bridge has been constructed at Site W1. One observed change to Site W2 was a substantial increase in faecal matter from cattle on the substrate in the river. Due to the prolonged low flow conditions this material has built up and was covering the stream bottom causing some algal development and some eutrification that may impact on water quality and stream biodiversity Site W1, viewed upstream (7), viewed downstream (8), taken October, Site W2, viewed upstream (9), viewed downstream (10), taken October,

44 Dog Trap Creek Site W3 Dog Trap Creek (Site W3) drains the forested escarpment area northeast of the project area and flows westward. During normal flow conditions the stream is fast flowing with a course sand and gravel substrate on a clay base. The downstream area is heavily impacted by cattle grazing and has a minimal riparian zone consisting mainly of Eucalyptus and Casuarina species. The stream banks and bed are impacted by cattle activity, with areas of bank erosion. During this survey the stream had a low flow with turbid water and clumps of algae within the pools signifying high levels of nutrients within the water. The stream substrate was covered with cattle faecal matter to a depth of several centimeters. Dog Trap Creek was sampled for water quality and macroinvertebrates Site W3, viewed upstream (11), viewed downstream (12), taken October, Methodology Macroinvertebrate Sampling Each site was sampled using two standardised methods outlined in the River Bioassessment Manual (Anonymous, 1994) and the NSW AUSRIVAS Sampling and Processing Manual (2000). For more detailed outline of methods used see Survey 5. Identification All samples were sorted under a stereomicroscope and stored in 70% alcohol. Specimens were identified to genus where possible, (except for Chironomidae, Oligochaeta and Platyhelminthes which are identified to family/subfamily), using a combination of current taxonomic works and keys and comparison with voucher specimens in the reference collections of Invertebrate Identification. Identification references included Williams (1981) and the taxonomic identification series produced by the Murray Darling Freshwater Research Centre. Data analysis SIGNAL.. SIGNAL is an acronym for Stream Invertebrate Grade Number - Average Level, and is a biotic index of pollution tolerance or sensitivity of stream invertebrates and was originally developed for use in the lower Blue Mountains (Chessman, 1995). Chessman et al., (1997) released a modified version; SIGNAL HU97, developed for the Hunter Valley, which is to the south, and its aquatic communities are more comparable to those found within the study area. See Table 2 for a breakdown of the SIGNAL values and water quality status. SIGNAL -HU97B Probable water quality status >7 Excellent 6-7 Good 5-6 Fair 4-5 Poor <4 Very poor 7

45 Table 2. Interpretation of water quality status using SIGNAL -HU97B scores (Chessman et al., 1997). EPT Richness. The EPT (Ephemeroptera, Plecoptera and Trichoptera) score is based on the observation that the majority of these taxa are particularly pollution sensitive (Lenat, 1988, see Table 3). For further details sees Survey 13. EPT genus richness Probable condition of macroinvertebrate community >6 Healthy 5-6 Slightly impaired 3-4 Moderately impaired 1-2 Severely impaired 0 Grossly impaired Table 3. Interpretation of the EPT genus richness scores (Besley et al., 1996; Besley & Growns, 1998). Number of Families. All macroinvertebrate families are separated and counted. The number of families present generally decreases with decreasing water quality and is used as a comparative measure of community change over time. Functional Feeding Groups. Ratio of shredder taxa to total number of taxa. As with Numbers of Families the higher the ratio of shredders the better the water quality and is used as a comparative measure of community change over time. Silt Tolerant Species The index of silt tolerant taxa has been added to the analysis of the macroinvertebrate data as the presence of such fauna can provide an indication of the degree of heavy sediment pollution. The main indicator families are the Dugesiidae, Lymnaeidae, Ancylidae, Planorbidae, Psephenidae, Chironomidae, Caenidae, Pyralidae and Ecnomidae. The silt tolerant taxa values are best examined against the total number of taxa sampled from each site i.e. the silt tolerant ratio, as the variation of values is significantly reduced compared with examining the number of taxa alone. This index is used as a comparative measure of community changes over time. Physico-Chemical Data Physical and chemical parameters were measured at each site in situ and included temperature, dissolved oxygen, conductivity and ph. Results Environmental Physico-chemical Conditions All physico-chemical parameters were remarkably consistent over the length of the study area and comparable with previous surveys (see Table 4). The river sites were well above the minimum requirements as set out by the ANZECC and ARMCANZ guidelines (2000). Rainfall (see Figure 1) over the last three months has continued to be in lower frequency and intensity similar to the same period last year (2008). Over the last twelve months there has been 15 rainfall events over 20 mm, and one wet period in February, 2009 where mm 8

46 fell over a ten day period with the highest single day fall of 81.1 mm falling on 15 Feb There have been a number of smaller rainfall events which has maintained a sustained flow in the rivers and creeks. The low flow period prior to the October survey caused salinity levels to rise at all sites. The moderate to high rainfall event in February through to July, 2009 resulted in a significant lowing of salinity levels (Figures 2-3.) in the smaller tributary sites including Sites W8 and W5. The river sites have remained consistently low and consistent with previous years flow regimes. As usual Sites S3 and W5 recorded the highest values with 2916 and 1256 respectively, this is approximately twice the salt load compared with last year s survey for Site S3. The river sites (Sites W1, W2 and W3) recorded consistently low values ranging from of 534 at Site W2 to 501 at Site W1. Figure 3 illustrates the annual changes in conductivity recorded as part of Stratford mine monthly monitoring program, for all sites (except Site S3) and shows that there were two periods of no flow (blank spaces) in Jan/Feb and Sept/Oct and all records were comparable and consistent with the value recorded for this survey. Survey 7 Units S3 W1 W2 W3 W5 W8 Temperature C C dry Conductivity Data mg/l dry ph Units ph Units dry Dissolved Oxygen ms dry Table 4. Physico-chemical data from each site collected on 8th October Daily Rainfall Rainfall (mm) /10/ /11/ /12/ /01/ /02/ /03/ /04/ /05/ /06/ /07/ /08/ /09/ /10/2009 Time Figure 1. Daily rainfall values for Stratford from October 2008 to October During the current round of sampling the water temperatures (Figure 4) was lower than the previous survey across all sites. The values are also still relatively constant throughout the system. Sites W5 and W2 recorded the highest temperature of 13.7 C, and 14.0 C, respectively, while Site S3 recorded the lowest value of 12.5 C. 9

47 The ph (Figure 5) has remained very consistent over the last three years. There has been very little fluctuation of ph throughout the system over time and it is therefore not considered to have a major impact on stream biodiversity. Figure 6 illustrates the annual changes in ph recorded by the Stratford Mine s monthly monitoring program, for all sites, except Site S3, and shows that there were periods of no flow (blank spaces) during the last summer period. All sites recorded were comparable and consistent with the value recorded during the current survey. Conductivity 8000 Conductivity(mg/l) Sep-01 Dec-01 Apr-02 Mar-03 Mar-03 Mar-04 Nov-04 Time Nov-05 Oct-06 Oct-07 Oct-08 Oct-09 S3 W1 W2 W3 W5 W8 Figure 2. Fluctuations in conductivity of the Avon River, Avondale Creek and Dog Trap Creek from Annual Conductivity Conductivity (mg/l) Oct Nov Dec Jan Feb-09 19/02/2009* 23/02/2009* 24-Mar Apr May-09 Date 23-Jun Jul Aug Sep Oct-09 Figure 3. Fluctuations in annual conductivity of the Avon River, Avondale Creek and Dog Trap Creek during W1 W2 W3 W5 W8 10

48 Temperature S3 Degrees C W1 W2 W3 W5 5 0 Sep-01 Dec-01 Apr-02 Mar-03 Mar-03 Mar-04 Nov-04 Time Nov-05 Oct-06 Oct-07 Oct-08 Oct-09 W8 Figure 4. Fluctuations in water temperature of the Avon River, Avondale Creek and Dog Trap Creek from ph S3 6 W1 ph Units Sep-01 Dec-0 1 Apr-02 Mar-03 Mar-03 Mar-04 Nov-04 Time Nov-05 Oct-06 Oct-07 Oct-08 Oct-09 W2 W3 W5 W8 Figure 5. Fluctuations in ph of the Avon River, Avondale Creek and Dog Trap Creek from Dissolved oxygen has shown consistent values across all sites. (See Figure 7) and has remained relatively consistent with last year s survey. Sites S3 and W1 recorded the lowest readings with 1.7, while the highest observed value was 2.8 for Site W5. The higher DO 11

49 reading at Site W5 is possibly due to the increased algal activity due to low flow conditions and high levels of solar radiation stimulating the production of oxygen during the day. The lower DO reading recorded at Site S3 is consistent with a reduction in solar radiation due to the often dense riparian zone of vegetation, which would therefore reduce the production and activity of algae. Annual ph ph units W1 W2 W3 W5 W8 Oct-08 Dec-08 Feb-09 Apr-09 Jun-09 Aug-09 Date Figure 6. Fluctuations in annual ph of the Avon River, Avondale Creek and Dog Trap Creek from Dissolved Oxygen DO /09/ /12/2001 3/04/ /03/ /03/ /03/ /11/2004 Time 16/11/ /10/ /10/2007 2/10/2008 8/10/2009 S3 W1 W2 W3 W5 W8 Figure 7. Fluctuations in Dissolved Oxygen of the Avon River, Avondale Creek and Dog Trap Creek from

50 Ecological Response - Macroinvertebrate Data A total of 53 genera representing 38 families were recorded from five sites. The results of the survey and the indices values are summarised in Tables 5 and 5a.The indices indicate that although all sites demonstrate some degree of disturbance the Avon River sites can be classed as healthy to slightly impaired. Avondale Creek is generally in poor to very poor condition using the SIGNAL index or from slightly impaired to moderately impaired using the EPT index. Dog Trap Creek (Site W3), which is the control site is in very poor condition to grossly impaired condition. The biodiversity values (i.e. number of genera) are illustrated in Figure 8. The total numbers of genera and families have shown a small decrease in the overall biodiversity for both Avon River sites and Avondale Creek, compared with the values of a year ago but comparable with previous years surveys. Whereas Site S3 recorded the only increase. Sites W3 and W5 recorded the lowest biodiversity value of 15 and 17 taxa, respectively. Sites W1 recorded the highest diversity with 34 genera, whereas W2 recorded the second highest score of 32 genera. This values represent overall consistent values to the previous 4 surveys. The results are also comparable with the results recorded in December, 2001 prior to the drought period of Survey 7 S3 W1 W2 W3 W5 SIGNAL - HU97B No of Genera No of Families EPT EPT ratio Shredder Ratio Silt Tolerant Taxa Table 5. Macroinvertebrate indice results for Survey 7, October Survey 7 S3 W1 W2 W3 W5 W8 SIGNAL-HU97B Poor Poor Poor Very Poor Very Poor dry EPT Slightly impaired Healthy Slightly impaired Grossly impaired Moderately impaired dry Table 5a. Macroinvertebrate indice results for Survey 7, October The SIGNAL values for all sites, except Site W3 recorded lower values to the previous survey (see Figure 9) but comparable values with the previous year s survey. The two Avon River sites (Sites W1 and W2) and Site S3 once again recorded high values while the highest value of 4.5 was recorded at Site W1, which was comparable to the 2001, 2003 and 2004 values. This indicates that ecologically, the condition of the river has remained constant over the last twelve months. Sites W3 and W5 recorded the lowest values with 3.8 and 3.7, respectively. The SIGNAL values indicate that all sites, except Site W3, are considered to be in poor condition while Site W3 is considered to be in very poor condition. The EPT values (Figure 10) reflect both the biodiversity and SIGNAL Indices by showing a significant decrease in the number of EPT taxa recorded at all sites compared with the previous years survey. The current results are, however, comparable with the previous year s results and years 2002, 2004 and 2006 surveys. All sites recorded a decrease on previous years, with Sites W1 recording the highest values of 8 EPT taxa, indicating a healthy ecosystem. Site W3 recorded the lowest with 0 EPT taxa, indicating that this system was grossly impaired. The other sites recorded values that indicate that they range from slight to moderately impaired. There was a slight decrease in both biodiversity and ecosystem condition indices recorded between Sites W1 13

51 and W2 however, the differences were minimal compared with previous surveys and between the test sites and the control sites. The general decrease in EPT taxa across all sites is attributed to a prolonged period of low to no flows this adversely impacting on water quality. Biodiversity No of Genera S3 W1 W2 W3 W5 W8 27/09/ /09/ /09/ /09/ /09/ /09/2006 Time 27/09/ /09/ /09/2009 Figure 8. Fluctuations in aquatic biodiversity (number of genera) in the Avon River, Avondale Creek and Dog Trap Creek from SIGNAL Index SIGNAL S3 W1 W2 W3 W5 W8 27/09/ /09/ /09/ /09/ /09/ /09/2006 Time 27/09/ /09/ /09/2009 Figure 9. Fluctuations in the environmental condition (SIGNAL Index) of the Avon River, Avondale Creek and Dog Trap Creek from The decreases in EPT values are tempered when examined as a ratio of EPT taxa to total number of animals collected. Figure 11 illustrates the EPT Ratio values for all sites survey since 2001 and shows that there has not been a significant change in the number of EPT taxa for the last six 14

52 years. Overall, since sampling begun there has been a gradual increase in the number of EPT taxa across all sites with the exception of Site W3, which is lower than the value observed in EPT Index 12 No. of EPT taxa S3 W1 W2 W3 W5 W8 27/09/ /09/ /09/ /09/ /09/ /09/2006 Time 27/09/ /09/ /09/2009 Figure 10. Fluctuations in the environmental condition (EPT) of the Avon River, Avondale Creek and Dog Trap Creek from EPT Ratio EPT ratio S3 W1 W2 W3 W5 W8 27/09/ /09/ /09/ /09/ /09/ /09/2006 Time 27/09/ /09/ /09/2009 Figure 11. Fluctuations in the environmental condition (EPT Ratio) of the Avon River, Avondale Creek and Dog Trap Creek from The results of the EPT index and EPT ratio are reflected in the shredder ratio that is showing a decrease at Sites W2, W3 and W5, while Sites W1 and S3 showed an increase compared with previous studies. The recorded values at Sites W1 and S1 were well above those observed for the 15

53 previous six years, while for Site W3 it was the second lowest. Since 2005 Site W3 has demonstrated a steady decline in condition, although the current results are comparable with those of This pattern in ecosystem condition values is attributed to the continued low flow conditions that have occurred this year. The combined results indicate that the aquatic ecosystems are still being impacted from the current and previous low flow conditions. Shredder Ratio Shredder Ratio S3 W1 W2 W3 W5 W8 27/09/ /09/ /09/ /09/ /09/ /09/2006 Time 27/09/ /09/ /09/2009 Figure 12. Fluctuations in the environmental condition (Shredder Ratio) of the Avon River, Avondale Creek and Dog Trap Creek from The aquatic macroinvertebrate taxa recorded are listed in Appendix 1 and represents a community consisting generally of species tolerant of moderate to high levels of disturbance with a decrease in disturbance sensitive taxa. At all sites, the communities were dominated by predator feeding groups such as Coleoptera, Hemiptera and the detritivore feeding groups including an array of Chironomidae and Oligochaete and shredder/grazer guilds including the Ephemeroptera and Gastropoda (see Figure 12). The prevalence of Chironomidae in the soft sediments of the Avon River and Dog Trap Creek were particularly significant as they indicate that there has not been sufficient flows for a substantial period to flush out the finer sediment, detrital matter or cattle faecal matter. This is particularly true in Dog Trap Creek where a substantial layer of cattle faecal matter and fine sediments has accumulated over what was once a gravel and cobble bed stream. This is also the only site where there was a complete disappearance in EPT taxa and a marked reduction in Shredders. The most notable feature of all sites sampled is the decreases in the shredder/grazer functional feeding group, (except at Site W3). The major component collected during this survey, for this feeding group, includes the Orders Ephemeroptera (mayflies), Trichoptera (Caddis Flies) (EPT) and the snails (Gastropoda). The high to moderate EPT scores, ranging from 4-10 are indicative of healthy to slightly impaired streams, whereas streams that have only recorded 2 EPT taxa (i.e. Site W3) are indicative of ecosystems experiencing a degree of stress associated with very low to no flow conditions and the subsequent decrease in water quality parameters. As indicated above, this low value equates to the ecosystem condition being severely impaired. A notable absence in all of the sites is that of the Plecoptera (Stoneflies) (which are particularly sensitive to habitat disturbance), that had been previously observed at both sites on the Avon 16

54 River (Sites W1 and W2). The Mayfly family Leptophlebiidae (Ephemeroptera), which were absent from all sites in 2003 were observed at both river sites (Sites W1 and W2) and the upper section of Avondale Creek (Site S3) in the current survey. The presence of the dragonfly family Megapodagrionidae is notable, as the presence of this family at Site S3 is an important addition to the fauna as this family is highly sensitive to disturbance and is normally only found in pristine streams. These groups are allocated the highest rating (10) in the SIGNAL index, as they are highly sensitive to pollution/disturbance. Therefore, the continued existence and substantial increase in numbers and coverage at these sites is indicative of a continued sustainability in ecosystem condition. The absence of the Plecoptera and reduced numbers of Ephemeroptera and others of the shredder/grazer functional feeder group at Sites W3 and W5 can be attributed to two main factors. The first is the impact of prolonged low to no flow conditions in the rivers. These conditions result in still pools with low oxygen levels and possibly thermal and haline stratification encouraging anoxic bottom layers in the pools or the creek drying out completely as occurred in Site W8 in early These conditions stimulate groups that inhabit still water bodies and reduce those taxa that require flowing water. The second is that much of the fauna recorded during the current and the previous round of sampling are species tolerant of disturbance and as well as appearing to be tolerant of moderate to high levels of salinity. During this round of sampling and over the last twelve months there was a substantial increase in salinity levels, particularly in the tributary streams, due to the low flow conditions. The little to no rain since July/August has substantially increased salinity levels. The previous and current notable absences include the Plecoptera (Stoneflies), the Ephemeropteran family Leptophlebiidae (Mayflies), Orthocladinae Chironomid midges (Diptera), Corydalidae (Megaloptera), the Trichopteran families Hydropsychidae, Odontoceridae as well as the freshwater mussel family Hyriidae. These groups have been found in less impacted, higher flow and less saline systems such as Dog Trap Creek in the past and have been found consistently in the Avon River and in time with regular, higher flows will return to the other streams. Discussion The condition of the aquatic macroinvertebrate communities in the Avon River, Avondale Creek and Dog Trap Creek has decreased compared with the previous year across all sites, except for Site S3, which showed an improvement. Water quality has also shown an overall decrease at all sites as a result of the low to no flows that have occurred over the second half of At the time of sampling the Avon River was approximately 1 cm over the causeway at Site W1 and 3 cm over the causeway at Site W2 and not running at all other sites. Site W8 was dry. The biodiversity and the overall health of the Avon River at Sites W1 and W2 and all site except for Site S3, was lower than the previous survey but comparable or higher than earlier surveys. It is clear from the results that the two main factors influencing the biological diversity in the Avon River and Avondale Creek systems are the water chemistry (particularly salinity) and flow levels. The influence of salinity on biological activity is variable and depends on the sensitivity or physiological salinity thresholds of each aquatic species. There is an inverse relationship between biological activity and salinity levels. As salinity increases biodiversity decreases. The reverse is also certainly true i.e. as salinity decreases, generally, biodiversity increases. The Avon River catchment has a naturally high soil and groundwater salinity, which is attributed to the geology of the area i.e. coal and shale deposits are typically associated with highly saline groundwaters. The long-term changes that have occurred in the rivers can be seen in Figure 2. This graph shows that the salinity in the Avon River and Dog Trap Creek has remained relatively consistent over a six year period, with an increase during the worst of the drought conditions during 2002 and 2004 whereas the salinity of Avondale Creek, particularly Sites W5 and S3, has had significant fluctuations. These fluctuations have been attributed to the second main contributing factor of ecosystem health i.e. the level and 17

55 intensity of rainfall events that translates into river flows and the dilution affect of higher river flows on water chemistry levels including salinity. Flow is the major factor that determines water chemistry and, therefore, levels of biological activity, diversity and community structure. The impact of extended periods of reduced flows to no flow, combined with an increase in evaporation over the warmer summer months will result in a reduction in the dilution of the saline groundwater discharges that enters the streams, particularly within the more ephemeral streams. Aquatic communities are tuned to the natural flow conditions of the water body they inhabit (e.g. a pool or wetland). Thus the community that exists there is composed of a suite of species that are adapted to the particular habitats present and the environmental physico/chemical constraints found there. Therefore, when the environmental conditions change during periods of extreme flow conditions such as very high flows or no flows, the macroinvertebrate communities will fluctuate depending on the particular requirements of the habitats present. During periods of high flows or floods many aquatic invertebrates are removed by scouring of the substrate through the mechanical action of high current velocity or by active dispersal/migration whereby many aquatic invertebrates swim into the current and drift downstream to colonise other sections of the river. These factors can lead to an apparent reduction in biodiversity from a site. Conversely, during periods of low or no flow, biodiversity (i.e. numbers of individual species, not necessarily numbers of animals) is often reduced due to a reduction in water quality parameters such as an increase in concentration of nutrients and or minerals such as salt, through evaporation. However, salinity is not the only parameter affecting community structure (Kefford, 1998), for example no flow periods often correspond to the summer period with increases in water temperature and reductions in dissolved oxygen or in extreme cases, thermal stratification of the water column resulting in anoxic conditions at the bottom of pools. Extended low flows also allow detritus, organic matter and in areas of intensive cattle grazing and access to waterways, a built up of cattle faecal matter on the substrate, as was clearly evident at Sites W2 and W3. This organic material consumes oxygen during the decomposition process and can strip or lower oxygen levels in a still pool to critically low levels impacting on the aquatic invertebrates and vertebrates. Avondale Creek is naturally an intermittent stream, whose flow is normally derived from two natural sources: rainfall runoff and groundwater seepage. A third source in the past has been the release of water from the Eastern Water Storage Dam within the mine over a three-year period. This source of flow has now been eliminated for some years due to the cessation of mining in the Stratford coal mine and the filling of the main pit with the water from the storage dam. The groundwater seepage is highly saline with values of up to s/cm being recorded during periods of low flow in the past (see Figures 2-3). Whereas, during periods of high rainfall events, the salinity levels at all sites are significantly reduced. The current period of low flow appears to have elevated the waterway conductivity prior to the October sampling. Therefore, there is a direct relationship between levels of flow, water salinity levels and biological diversity. Aquatic biodiversity, in particular EPT taxa, is also dependent on the season in which impacts such as high salinity/low flows occur and the length of time the river systems are under stress. Under normal yearly flow patterns; there is a seasonal reduction in mature larvae that occurs in late summer/early autumn corresponding to the timing of low flows. Most of the EPT taxa emerge as adults from spring through summer where upon the winged adults live for a brief period during which they breed and lay eggs before dying. The late summer / early autumn period is usually a time where stream biodiversity appears to decline until late autumn / winter, during which time, the eggs laid in summer hatch and the biodiversity returns to expected levels. However, if the streams were dry or not flowing, as was the case during the summer and autumn period , there would be no recruitment during autumn - winter as there would be no eggs laid in these streams during the summer period and this would, therefore, result in depressed EPT numbers in the following year. This group of aquatic invertebrates requires permanent water 18

56 bodies to exist. The lack of sustained flow and a reduction in water quality would result in a reduction in the EPT group. The opposite is also true where if there is a sustainable flow occurring in the river system over an extended period populations are able to expand and recolonise areas previously unsuitable. This would therefore result in an increase in the number s of sensitive taxa, an increase in the complexity of the community and increase in the overall condition of the ecosystem. Therefore, if this pattern occurs over a number of years, as has appeared to have happened in this study, then the population of EPT taxa (and biodiversity) would noticeably increase. In conclusion, the results from the current and previous surveys suggest that the prolonged low to no flow conditions have had a long term adverse impact on the aquatic macroinvertebrate community and overall health of the Avon River and its tributary streams. This impact can be seen in all sites, except for Site S3, which has been sustained by groundwater seepage and a healthy riparian zone. The whole Avon River system still requires a substantial increase in rainfall over an extended period to reach the levels previously recorded at all sites, however, this survey also indicates that there are no adverse impacts on the Avon River and its tributaries that are associated with the operations of Stratford Mine. This is due to the results showing consistent values for sites within the mining area as well as the control sites outside the area of mining operation. Acknowledgements We are grateful to Alarna Pain and Mr James Benson for their assistance in the field and for providing background information on water quality and site history. References Anonymous National River Processes and Management Program Monitoring River Health Initiative. River Bioassessment Manual Version 1.0. Department of the Environment, Sport and Territories, Canberra. Besley, C.H., McEvoy, P.M. and Chessman, B.C Biological Assessment of the Streams in the Stratford Coal Project Area. Australian Water Technologies, Ensight, Report Number 96/152. Besley, C.H. and Growns, I Biological Assessment of the Streams in the Stratford Coal Project Area. Australian Water Technologies, Ensight, Report Number 98/144. Chessman, B.C Rapid assessment of rivers using macroinvertebrates: a procedure based on habitat-specific sampling, family-level identification and a biotic index. Australian Journal of Ecology 20(1): Chessman, B.C., Growns, J.E. and Kotlash, A.R Objective derivation of macroinvertebrate family sensitivity grade numbers for the SIGNAL biotic index: application to the Hunter River system, New South Wales. Marine and Freshwater Research 48: Kefford, B.J. (1998). The relationship between electrical conductivity and selected macroinvertebrate communities in four river systems of south-west Victoria, Australia. International Journal of Salt Lake Research 7: Lenat, D.R Water quality assessment of streams using a qualitative collection method for benthic macroinvertebrates. Journal of the North American Benthological Society 7(3):

57 Williams, W.D Australian Freshwater Life. The Invertebrates of Australian Inland Waters. Macmillan Education Australia Pty Ltd. Melbourne. 20

58 Appendix 1. A list of macroinvertebrate genera found at the six sample sites. Order Family Genera S3 W1 W2 W3 W5 W8 Bivalvia Sphaeridae Pisidium * * * * Coleoptera Dystiscidae Bidessodes * * Coleoptera Dystiscidae Bidessus * * * * Coleoptera Dystiscidae Necterosoma * * * * Coleoptera Dystiscidae Paroster * * * Coleoptera Elmidae Austrolimnius * * Coleoptera Gyrinidae Macrogyrus * * * * Coleoptera Haliplidae Haliplus * * Coleoptera Hydrophilidae Berosus * * * Coleoptera Hydrophilidae Enochrus * * * * Coleoptera Hydrophilidae Hydrochus * Coleoptera Psephenidae Sclerocyphon * * * Coleoptera Scirtidae Undetermined * * Decapoda Atyidae Caridinides * * * * Decapoda Atyidae Paratya * * Diptera Chironomidae Chironominae * * * * * Diptera Chironomidae Orthocladinae * * * Diptera Chironomidae Tanypodinae * * * * Diptera Culicidae Culicinae * * * Diptera Dixidae Dixa * Diptera Stratiomyidae Odontomyia * Diptera Tipulidae Undetermined * * Ephemeroptera Baetidae Cloeon * * * Ephemeroptera Caenidae Tasmanocoenis * * Ephemeroptera Leptophlebiidae Atalophlebia * * * Ephemeroptera Leptophlebiidae Austrophlebioides * Gastropoda Ancylidae Ferrissia * * * Gastropoda Lymnaeidae Austropeplea * * Gastropoda Physidae Haitia acuta * * * * Gastropoda Planorbidae Gyraulus * Gastropoda Planorbidae Helicorbis * Gastropoda Planorbidae Isidorella * Hemiptera Corixidae Agraptocorixa * Hemiptera Corixidae Micronecta * * * Hemiptera Corixidae Sigara * Hemiptera Notonectidae Enithares * Hemiptera Pleidae Plea * * * Hemiptera Veliidae Microvelia * * Hirudinea Glossiphoniidae Undetermined * Megaloptera Sialidae Austrosialis * Odonata Coenagrionidae Ischnura * * * * Odonata Hemicorduliidae Hemicordulia * Odonata Libellulidae Diplacodes * Odonata Megapodagrionidae Austroargiolestes * * Oligochaete Lumbricidae Lumbricus * * * * Oligochaete Tubificidae Undetermined * * Platyhelminthes Dugesiidae Undetermined * * * Trichoptera Calamoceratidae Anisocentropus * Trichoptera Ecnomidae Ecnomus * * * Trichoptera Hydroptilidae Hellythira * 21

59 Trichoptera Leptoceridae Notalina * * Trichoptera Leptoceridae Oecetis * * Trichoptera Leptoceridae Triplectides * * * S3 W1 W2 W3 W5 W8 SIGNAL - HU97B No of Genera No of Families EPT EPT ratio Shredder Ratio Silt Tolerant Taxa

60 Stratford Coal Pty Ltd Stratford Coal Mine BLAST MONITORING Annual Environmental Management Report June 2010

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62 Stratford Coal Pty Ltd Stratford Coal Mine COMPLAINTS (EPA and DoP only) Annual Environmental Management Report June 2010

63 Stratford Coal Pty Ltd Stratford Coal Mine GROUNDWATER MONITORING Annual Environmental Management Report June 2010

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66 Stratford Coal Pty Ltd Stratford Coal Mine NATIONAL POLLUTANT INVENTORY Annual Environmental Management Report June 2010

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71 Stratford Coal Pty Ltd Stratford Coal Mine NOISE SURVEY REPORTS Annual Environmental Management Report June 2010

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73 Stratford Coal Pty Ltd Stratford Coal Mine SURFACE WATER MONITORING Annual Environmental Management Report June 2010

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79 Stratford Coal Pty Ltd Stratford Coal Mine APPENDIX III WEATHER DATA (EPA and DoP ONLY) Annual Environmental Management Report June 2010

80 Stratford Coal Pty Ltd Stratford Coal Mine APPENDIX IV ANNUAL REHABILITATION REPORT FORM (DII & DoP ONLY) Annual Environmental Management Report June 2010