WIMMERA – SPRING 1993

Publication 499 May 1996

Introduction salinity, temperature, turbidity, nutrient levels, toxic substances and the amount of oxygen Careful management of our waterways and dissolved in the water. These measures provide catchments is crucial to maintain and improve a ‘snapshot’ of environmental conditions at the river health. Good decision making requires moment samples are taken. Water quality detailed information on the environmental conditions are variable, so such monitoring can condition of our rivers. The Monitoring River fail to detect occasional changes or intermittent Health Initiative – a biological monitoring pulses of pollution. program across Australia – is part of the National River Health Program funded by the In contrast, the biological monitoring program Commonwealth Environment Protection involves sampling aquatic animals, which gives Agency. In Victoria the program is being an indication of the health of the river as a carried out by the Environment whole. Because they live at the Protection Authority (EPA) and site for some time, animals Water Ecoscience (formerly the reflect the build-up of impacts of State Water Laboratory). environmental change on the Caddis fly larva Having undertaken biological river ecosystem – such as the monitoring in Victoria since 1983, influence of surrounding land use EPA has a great deal of experience in the field. or the effects of pollution. The results of previous studies will be combined with those of the current program, providing a solid background of data. This will be used to Biological monitoring techniques determine long-term trends in the health of our Aquatic macroinvertebrates (such as insects, rivers and will help the protection of water snails and worms) are very useful indicators in quality and the beneficial uses of our water biological monitoring. They are visible to the courses. naked eye and are commonly found in rivers and streams. They are an important source of food for fish and many are well known to anglers – Monitoring water quality such as yabbies, mudeyes, stoneflies and Traditional water quality monitoring involves mayflies. They are widespread, easy to collect, measuring physical and chemical aspects of the relatively immobile and provide good water. Common measurements include pH, information about the environment. The presence or absence of specific species ¨ Kick samples provides information about water quality. Some To conduct kick samples, the stream bed species are known to have particular tolerances is disturbed by the sampler’s feet to to environmental factors such as temperature or dislodge animals which are swept into a net levels of dissolved oxygen. Other information can by the current. Samples are taken from be obtained from the number of species found at shallow areas with stony or rocky a site (biological diversity), the number of animals substrates in medium to fast currents. This found at a site (abundance) and the relationship type of habitat is called a riffle and is usually between all animals present (community associated with upland streams. structure). ¨ Sweep samples Sites with a high level of species diversity Sweep samples are collected by sweeping generally have good water quality. Sites which a net along banks and around snags in have low diversity are less healthy – often due to backwaters and pools which have slow the impacts of pollution. In polluted habitats, currents. Aquatic plants (macrophytes) – sensitive species are eliminated and less sensitive which provide additional habitat for aquatic species show an increase in numbers. animals – are often found in these habitats and are included in the sweep sample. Reporting results These habitats can be found in both the upland and lowland reaches of rivers. By the end of the three year biological monitoring program, a base of biological Water quality measurements are made at each assessment will have been completed for all the site and water samples are taken for laboratory major river basins in Victoria. analysis. The vegetation along the river banks (the riparian zone) and the aquatic habitat are also This series of bulletins will provide a brief assessed. The aquatic habitat is those parts of summary of the data for each river basin as it the river environment which animals use to make becomes available. Comprehensive a home. It can be strongly affected by the riparian assessments will be published following zone as well as the environment and land use of completion of the program. surrounding and upstream regions.

Study site selection and assessment For example, if fertiliser runoff is causing an excess of nutrients to enter the river, there may Monitoring sites are selected to include a be excess growth of algae attached to rocks and variety of sites believed to be representative snags in the river, affecting these important of the river basin’s waterways. habitats. It can also result in Sites subject to the impact of blooms of toxic blue-green algae pollution and those which are which are potentially hazardous relatively unimpacted are to humans, animals and birds chosen, although most are contacting or consuming the situated away from any obvious water. Thus different factors can point source of pollution. influence many parts of the river environment. Biological Sites are currently being sampled monitoring can be a valuable tool twice a year (autumn and spring) to measure the overall effect of using the rapid bioassessment all these influences. technique. This involves collecting two types of biological samples where possible. Riparian habitat Figure 1 Species numbers at sampling sites in Wimmera – Spring 1993 WIMMERA BASIN REPORT – SPRING 1993

Comments and upstream of Horsham, Wimmera River up- stream of Horsham, and Richardson River at The Wimmera basin has been highly modified by Donald and Carrs Plain Road. agricultural activities – particularly land clearance, use of agricultural chemicals, interconnection of Nitrogen and phosphorous levels exceeded the rivers with channels, and the extraction of a high guidelines in Wimmera River downstream of proportion of the flow for irrigation. Large towns McKenzie River, and Avon River. are situated on Wimmera River and Richardson River, and salinity is a major problem in the re- Figure 1 is a map of the Wimmera basin showing gion. Each of these impacts upon the rivers and monitoring sites and the number of invertebrate creeks. species found at each site.

Sampling was carried out during a dry period and most sites did not have suitable fast flow areas Related EPA Publications for kick samples. Kick samples were taken at Fyans Creek (Site 1), McKenzie River near Biological monitoring of the invertebrates, Zumsteins (Site 2), and the Wimmera River at phytoplankton and diatoms of the Glenorchy (Site 5) and Eversley (Site 4). Sweep Wimmera River samples were taken at all sites. EPA SRS 90/019, August 1993

The number of species was highest in the The effects of salinisation on stream inverte- Grampians at Fyans Creek and McKenzie River brates. Part II. Invertebrates, algae and near Zumsteins. This is partly due to both kick water quality of saline pools in the Wimmera and sweep samples being taken at these sites. River Most species were indicative of high water qual- EPA SRS 92/002, in preparation ity, although McKenzie River exceeded EPA’s State Environment Protection Policy – Waters of preliminary nutrient guidelines for total nitrogen. the Wimmera River and Catchment As expected, species richness was reduced in the Victorian Government Gazette No. 49, slower flowing streams on the plains north of the May 1985 Grampians. Most animals at these sites were very tolerant of pollution, and most were air breathers Preliminary Nutrient Guidelines for Victorian or tolerant of low oxygen levels. Richardson River Inland Streams at Donald (Site 12) and Wimmera River down- EPA Publication No. 478, June 1995 stream from Dimboola (Site 8) yielded the low- est number of species. However, at many of the sites, the observed higher diversity was due to Further Information larger numbers of air breathing groups such as EPA Customer Service & Information Centre beetles and bugs. Olderfleet Buildings 477 Collins Street, Melbourne 3000 EPA’s preliminary nutrient guidelines for nitrogen Telephone: (03) 9628 5622 were exceeded in McKenzie River near Zumsteins