University of Wollongong Research Online Faculty of Science - Papers (Archive) Faculty of Science, Medicine and Health January 2010 Catchments and Waterways Bob Bourman University of Wollongong, [email protected] Nick Harvey Simon Bryars Follow this and additional works at: https://ro.uow.edu.au/scipapers Part of the Life Sciences Commons, Physical Sciences and Mathematics Commons, and the Social and Behavioral Sciences Commons Recommended Citation Bourman, Bob; Harvey, Nick; and Bryars, Simon: Catchments and Waterways 2010, 65-86. https://ro.uow.edu.au/scipapers/707 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Catchments and Waterways Keywords waterways, catchments Disciplines Life Sciences | Physical Sciences and Mathematics | Social and Behavioral Sciences Publication Details Bourman, B., Harvey, N. & Bryars, S. (2010). Catchments and Waterways. In C. B. Daniels (Eds.), Adelaide : water of a city (pp. 65-86). Kent Town, South Australia: Wakefield Press. This book chapter is available at Research Online: https://ro.uow.edu.au/scipapers/707 64 CHAPTER 3 Catchments and Waterways Authors: Bob Bourman Nick Harvey and Simon Bryars 65 Introduction The major part of the Adelaide occupies the alluvial lowlands Faults of Adelaide between Gulf St Vincent and the Mount Lofty Ranges. The landscape rises to the east and south along the lines of the faults that underlie Adelaide (Figure 3.1). The vast majority of the streams that traverse the plains originate in the ranges, as r a Rive illustrated in Figure 1.1. There is a marked asymmetry of the le Par Litt River Torrens across the plains, where it is dominated by left bank tributaries. Relatively high precipitation in the ranges Dr y C feeds the streams of the lower country. The original streams ree k rarely reached the coast but petered out on the plains or formed wetlands dammed back by the dune barriers that !ank the shoreline. lt u a F a r Figure 3.1: Faults of Adelaide a P t l u lt a u F a y F Catchments of the Adelaide region e e ll There are four major catchments occurring in the a id V s River Torrens e n metropolitan region: the Northern Adelaide and Barossa, the p r o u Torrens, the Patawalonga, and the Onkaparinga. A drainage H B B basin or catchment may be de"ned as ‘… an area of land ro w that collects water, which drains to the lowest point in the area n H S il which could be either a lake, a dam, or the sea. Rain falling on t l u r lt Cre the land will make its way to this lowest point, via creeks, rivers t u e a k F n and stormwater systems. As well as rivers, creeks, lakes and e d E dams, a catchment also includes groundwater, stormwater, 1 wastewater, and water-related infrastructure’ . River 0 5 The Patawalonga catchment comprises 230 km2 and kilometres encompasses a large part of metropolitan Adelaide. It Coastal Plain Golden Grove Basin includes Brownhill Creek, Keswick Creek, the Sturt River and the Airport Drain which !ow into the Patawalonga Lower Alluvial Plain Eden Fault Block Basin at Glenelg. The comparatively larger catchment area Upper Alluvial Plain of Northern Adelaide and Barossa covers almost 2,000 km2 Upper Alluvial Plain and Para Fault Block and includes the Gawler River, which forms the northern boundary of the Adelaide Metropolitan Region, the South Para Fault Block Para and North Para Rivers, Little Para River and Dry Creek. Figure 3.1 Major faults and geomorphic zones of the The Onkaparinga catchment comprises approximately 920 FigureAdelaide 3.1 area Major faults and geomorphic zones of the km2 and includes the Onkaparinga and Field Rivers, Christie AdelaideSource: Sheard area M.J. and Bowman G.M. (1996) : Soils, Creek, Pedler Creek and the Washpool Lagoon, ‘one of the Source:stratigraphy Sheard and M.J.engineering and Bowman geology G.M. of near (1996) surface : Soils, last remaining coastal lagoons in metropolitan Adelaide’2. The stratigraphymaterial of the and Adelaide engineering Plains. Mines geology and ofEnergy near South surface catchment of the River Torrens comprises 620 km2 with the materialAustralia, ofReport the Adelaide Book, 94 /9 Plains. Mines and Energy upper part of the catchment arising at Mt Pleasant, beyond withinSouth the Australia, Adelaide Report planning Book, region 94 /9 are quite di#erent with the Adelaide metropolitan area. In the lower part of the the Little Para being predominantly rural whereas the Dry catchment the Torrens has "ve major tributaries !owing Creek catchment has been signi"cantly altered by industrial from the hills, First, Second, Third, Fourth and Fifth Creeks. and urban development. The sedimentation in the Dry Creek It is signi"cant to note that the River Torrens was one of the catchment has led to management problems such as the major reasons for Colonel Light’s selection of the location of accumulation of 1.5 kt of sediment at the Walkleys Road Adelaide3. culvert in 1993 and another 0.7 kt in 19944. Elsewhere, there have been attempts to improve the quality of the catchment Channel and !oodplain modi"cations and management such as by the construction of the Salisbury Green"elds Human impact varies between the di#erent catchments. wetlands in the 1980s. Before discussing the four major catchments within the region it is worth noting impacts on the Gawler River at To the south, the Torrens catchment has been heavily the northern boundary. This river forms an administrative modi"ed. While the catchment has a higher conservation boundary between two councils but unilateral !ood value in the upper reaches this becomes patchy downstream protection works by either council may have major !ood and many lower sections no longer have any conservation impacts on the adjoining council. This highlights the need value because of extensive modi"cation. The Torrens used to to manage !ood issues on a catchment basis rather than on discharge into a low lying marsh area called the ‘Reedbeds’ administrative boundaries. The two northern catchments landward of the West Beach dunes. In times of high !ow, the water drained both to the north through the Port River 66 The Biodiversity of Buckland Park BOX 10 Buckland Park Lake is located approximately 30km north vegetation dominates the landscape, along the Gawler of Adelaide on the floodplain of the Gawler River. The River Chanel riparian woodlands are found and area consists of low, flat alluvial plains with widely spaced significant mangrove (Avicennia marina ssp. marina) stream channels feeding a number of shallow terminal forests are present at the shoreline. lakes. The damming of several of the stream channels of the Gawler River in around 1920 is thought to have One of the most notable features of the Buckland Park created the Buckland Park Lake¹. Although the hydrology Lake area is its importance for waterbirds. In 1991 of the mouth of the Gawler River has been altered, Buckland Park Lake was the single most important Buckland Park Lake is one of the few remaining breeding habitat for a range of waterfowl within the semi-natural places where rivers meet the sea on the Adelaide region¹. During 1989 and 1990 over 60 species northern Adelaide plains. The Draft Estuaries Policy & of waterbirds were recorded using the Buckland Park Action Plan for South Australia² listed Buckland Park Lake Lake and surrounding habitat. This included many as one of only four recognised estuaries north of species which are rarely encountered in the Adelaide Adelaide in the Gulf St Vincent (others included the region and 9 species which were recorded as breeding at nearby Salt Creek to the north and the Port River Barker the location (the report also cited a further 12 species Inlet System to the south). which were reported to have bred at the lake in previous years)¹. It is thought that the habitat is most suitable for The area surrounding Buckland Park Lake is dominated waterbirds due to the large influx of freshwater that by complex and diverse ecological characters which reaches the system which then remains in the area of includes coastal dune systems, estuarine and inter-tidal lignum, bulrush (Typha domingensis) and samphire which environments, river floodplains, seasonal river-channel floods each year. flows, open fresh water-bodies, mudflats and diverse vegetation including significant mangrove communities, Within the Buckland Park Lake area there is over 120 ha of samphire/saltmarshes, lignum shrublands and redgum lignum shrubland, which excludes the river redgum woodlands. Few other places near Adelaide support such woodland along the Gawler River where it is also present. a diverse range of habitats within such a small area. This represents 96% of the currently mapped remnant lignum shrubland in the Southern Mount Lofty Region!. At the landscape scale, the area has natural links with The importance this places on Buckland Park Lake’s role protected areas including the Pt Gawler Conservation in biodiversity conservation cannot be under estimated. Park and the Dolphin Sanctuary to the west. There is also These shrublands, combined with the flooding regime, a variety of freshwater and brackish areas such as contribute significantly to the protection of waterbird Thompson Creek, the Bolivar Sewage Treatment Works habitat and breeding cycles. and Middle Beach, which contain significant vegetation (Gahnia filum sedgeland) and potential habitat for the Buckland Park Lake must be considered an important Yellowish Sedge Skipper butterfly (Hesperilla flavescens biodiversity asset at both a site level and at the landscape flavia)³. Extensive salt evaporation pans occur to the scale. It is a valuable link between the freshwater riparian south and to the north and east the land use is system on the Gawler River and the inter-tidal saltmarsh dominated by agriculture with highly cleared and and mangrove communities at the coast and beyond to fragmented native vegetation.