I ~ I i.; I ! I I Ii Ii GRE~~TER Ti\REE I II II:1 d CITY COlJNCIL !I I :! I I -'" ... ,,... .. , ... I I I I I I I- I I WATER QUAllIT IN THE MANNING RIVER . I 1989 - 94 I I 1- I I- I I I I I -I ~_ ... ~ __•. .(-."._.,~ .............. -.--=r ,.---' _. I I I I I I I I~ a report prepared by I Anna Kaliska I­ SEWER & WASTE SERVICES CRE_ATER TAREE CITY COUNCIL 2 Palteney Street I: TAREE NSW 2430 . Phone (06S) 913 399 I, October 1994 I !::", I I I I I I 1 INTRODUCTION I 2 MONITORING PROGRAM I 2.1 Stations Location 2.2 Flow Conditions During Sample Collection '1 ····2.3 Parameters-Neasl:<.reci·- . -- .,. .... .......-;:;..:;._._... --. -:::;;....: .. -' I 3 TUE MANNING RIVER SYSTEM 3.1 Catchment Description I 3.2 Tidal Behaviour and Sediment Transport 3.3 Water Resources and the River Flow I 4 TUE SOURCES OF WATER POLLUTION I 4.1 Point Source Discharges 4.2 Diffuse Source Pollution I I 5 WATER QUALITY IN TUE MANNING RIVER ESTUARY 5.1 Salinity 5.2 Dissolved Oxygen I 5.3 Biochemical Oxygen Demand 5.4 Clarity 5.5 Bacteriological Characteristics I 5.6 Nutrients I 6 CONCLUSIONS I REFERENCES I I 'I I TABLES 1 1 Water Quality Sampling Stations 2 Manning River Flow at Killawarra Station I 3 Estimated Manning River Flow at Taree 1 4 Characteristics of Sewage Treatment Plant Effluent I FIGURES I I 1 Location of Sample Collection Sites 2 Tidal Characteristics of the Manning River Estuary I 3 Load Discharged to the Manning River Before and after Taree Sewage Treatment Plant Flow Diversion I 4 Salinity - Mean Values 1989-94 1 5 Surface Dissolved Oxygen 1989-94 6 Bottom Dissolved Oxygen 1989-94 I 7 Average Dissolved Oxygen Ratios 1986, I 91/92 and 93/94 8 Biochemical Oxygen Demand 1989-94 I 9 Secchi Disc 1989-94 I 10 Faecal Coliforms 1989-94 11 Faecal Coliform 1989/92 and 93/94 I 12 Total Phosphorus 1989-94 ,-'Jo I, 1,3 Total Nitrogen 1989-94 14 Total Phosphorus 1984-94 15 Total Nitrogen 1984-94 = I I 1 1 INTRODUCTION I The Manning River system is one of the major river systems in New South Wales and is seen as an important natural resource on a local, regional and state level. The region offers an attractive living conditions with the wide 1 range of aquatic recreational opportunities. Rapid expansion of tourist industry has been observed alongside with the traditional activities as I dairying, beef cattle and fishing. This report attempts to evaluate water quality in the estuary section of the Manning River and is a continuation of previous studies conducted by the I Environment Protection Authority in 1986 and Council in 1988. Since these studies were done, the pattern of human generated pollution discharge to the river has changed. On the one hand two high strength industrial discharges I were removed from the river, but on the other progressing urban development has generated increased amount of stormwater runoff. 1- -.. ·For·the ~rs-~ of this report the water quality of a waterbody.is defll~d~ a-_ measure of water suitability for particular users uses of the waterbody. Existing scientifically based criteria were used to develop water quality I objectives which represent the desirable, long-term goals of a water quality. Evaluation of the water quality in the Manning River estuary is made by determining to what extend these long-term goals were being met. The water quality objectives for the Manning River estuary are adopted from Australian I or overseas standards for each parameter measured. I 2 MONITORING PROGRAM Water quality data in the tidal section of the Manning River was obtained as a I result of Greater Taree City Council "River Monitoring Program". 2.1 Stations location I Water quality information was collected at 7 sampling locations in the middle to upper estuary, between downstream Dumaresq Island and just upstream of Wingham. Site selection was based upon land use and geographical criteria I ensuring all major impacts generated by land use activities, discharge location and major tributary inflows were included. Figure 1 shows location of sample collection sites together with sewage treatment plants discharge I points. The detail description of sample site locations is given in the table below. Table 1 I Water Quality Sampling Stations I Distance Station Location - (kin) No. I 15· 20 Downstream Dumaresq Island ' . 19- 25 Downstream Dumaresq Island bridge . - 23 40 South side Goat Island 26 48 Pacific Hi~hway brid~e at Taree I 30 49 3 kin upstream Taree •..:.± 41 60 Carpun~hat Peninsula I 44 70 600m downstream Win~ham bridge ! I _~-·_U_i:_._ .. .j - -- - - - - ..". - - - -- -.,- N ~ ~/Bo' ~ J> (J ';j ~I' . ~ "",. '~~ , 2/ o~~f' .If. ,?O~\ o to 20 30.tn r,o,i' • Sample Station Inlel &STV II Figure 1 Location of Sample Collection Sites ' I WATER QUALITY IN THE MANNING RIVER I 1989 - 1994 I rage 2 I At the end of 1992 the additional station was established just below Browns Creek inlet and numbered 42. I 2.2 Flow Conditions During Sample Collection Collection of river water quality data was carried out from May 1989 to July I 1994 and involved 17 data collection surveys with 1992-94 collections made regularly every 2 months. I As the program was primarily design to assess an impact of point source discharges, most surveys were conducted during medium and low flow in the ·-Rver. Only,ol1_3 .. o.ccaslliilli_lhe.r-i.ller. flow reached its medium_high 9119 .Q.l1.CE::.. _,." I . high VaTue; wnit.:ljoccurred during early 1989-92 stage of the stu~y perioEh'c ;,,--, Dates of sample collection with the river flow at Killawarra Station I (Department of Water Resources 1994) are presented below: Table 2 I Mannjng J1jver Flow at JfjJJawarra Statjon I Date Flow (MI/day) 10/5/89 13020 28/11/90 849 I 27/2/91 453 14/8/91 546 29/4/92 2839 I 30/6/92 3690 26/8/92 586 28/10/92 328 I 16/12/92 4581 24/2/93 1191 5/5/93 682 I 30/6/93 691 29/9/93 632 30/11/93 761 I 2/2/94 305 12/4/94 787 I 5/7/94 681 I 2.3 Parameters Measured In-field measurements included temperature, salinity, dissolved oxygen, I, Secchi disc and depth. The measurements of temperature, dissolved oxygen i and salinity were taken at depths of 0.1 m, 0.5 m and the bottom. Greater Taree City Council October 1994 I WATER QUALITY IN THE MANNING RIVER I 1989· 1994 Fage3 I The surface water samples were collected at each site and tested by ALS I Tradetest laboratory for biochemical oxygen demand, suspended solids, ammonia, total Keldjahl nitrogen, nitrate, nitrite, filterable reactive I phosphorus, total phosphorus and faecal coliform. In addition the collection of sewage treatment plants effluent samples was undertaken at each day of the river survey. The samples were tested by the I Laboratory for the same parameters as the river samples. I 3 THE MANNING RIVER SYSTEM " •.3.1 .--'.~'--- -'-~- --=::;.:- :'." ---. ."-- -- I The Manning River has a total catchment area of approximately 8400 square kill rising in the Mount Royal range at an elevation of 1000 to 1350 metres above sea leveL The majority of the catchment is hilly to mountainous with I only 10 per cent of the catchment area could be considered reasonably flat (Laurie 1980). I The most important upper tributaries are the Barnard, Nowendoc, Gloucester and Barrington Rivers, and Dingo and Cedar Party Creek. Below Mount George the valley broadens out, finally developing into a wide flood plain below I Taree. The lower estuary system is complex as the river forms a meandering network of narrow channels. The major tributaries in the lover catchment include Browns and Cattai Creeks, and the Dawson and Lansdowne Rivers. I The river has a permanent entrance to the ocean at Harrington and an intermittent opening at Old Bar. I Geologically the Manning River estuary can be classified as MatUre Age Barrier Estuary. This type of estuary can be created by extensive river systems with I relatively high sediment loads. During periods of sea level rise along the NSW coast large quantities of marine sand were transported landward and distinctive sand barriers were I formulated. Landward of these barriers estuaries were created in form of broad tidal lakes connected to the ocean by narrow tidal inlets through the I barrier (Estuary Management Manual, 1992). The high sediment loads have in filled the initial back-barrier lake with alluvium, formulating a complex system of sinuous river channels discharging I directly into the ocean through shallow entrance. I ·3.2 Tidal Behaviour and Sediment Transport The movement of water in and out of an estuary is typically dominated by the tides, except during times of flood. Tidal characteristic depend of estuary I shape, and as such the Manning River estuary is classified as Tidal River (Estuary Management Manual, 1992). I .. Greater Taree City Council october 1994 I I WATER QUALITY IN THE MANNING RIVER I 1989 - 1994 Fage4 The tidal range is elevated in upstream reaches of the Manning River estuary as a result of resonance effects. The nature of such effects is complex and I dictated by the depth and length of the main channel in relation to the frequency of the ocean tide. After initial elevation, tidal range decrease slowly seawards and shows a significant reduction as a result of tidal energy loses at I the heavily shoaled entrance.