Lawson Creek is a perennial Blue Mountains stream. The creek and the surrounding bushland and park areas are community owned natural assets managed by Blue Mountains City Council (South Lawson Park) and the NSW National Parks and Wildlife Service (Blue Mountains National Park and World Heritage Area).

• Lawson Creek supplies moisture and nutrients to  South Lawson Park, Blue Mountains National Park and the World Heritage Area.
• The creek and its water support indigenous plant and animal diversity in these areas.
• The creek contributes to the amenity and beauty of the popular and scenic bushwalking track located between Adelina and Junction Falls.
• The creek can be easily damaged by unmanaged stormwater flows, weeds, pollution and careless and selfish use by people.
• Unauthorised vegetation clearing, and the collection of indigenous animals, plants and landscape features, such as rocks, flowers, plant seeds and timber, are not permitted.

Lawson, Ridge and Cataract Creeks constitute a sub-catchment of Erskine Creek catchment. This catchment is a significant contributor to the Dyarubbin (Hawkesbury-Nepean River) catchment.

Lawson Creek is approximately four kilometers in length.

• The creek rises south of Lawson shopping centre and the Great Western Highway (GWH), via a series of minor tributary streams and drain lines that flow into a now quite altered swamp/lagoon complex.
• Originally there were many fine swamps in this upper catchment area (Waratah Street), but they are now largely degraded or non-existent. However, remnant peaty soils still contribute to surface seepage into the main stream.
• After forming into a single, distinct channel, Lawson Creek flows to Lawson Swamp, which is located approximately one kilometer south of the main Blue Mountains (GWH) ridge. Lawson swamp is part of a protected ecological community (EPBC Act C’wlth 1999; Biodiversity Conservation Act NSW 2016). See: https://www.bmcc.nsw.gov.au/environment/waterways/swamps
• Lawson swamp stores and feeds a constant supply of water via Lawson Creek to two spectacular and popular downstream waterfalls, Adelina and Junction Falls.
• At Junction Falls, the tributary Ridge Creek discharges into Lawson Creek. A little further south, Cataract Creek flows into Lawson Creek.
• Finally, a further two kilometres downstream, Lawson Creek terminates, discharging into Bedford Creek. The latter flows into Glen Erskine Creek to form Erskine Creek, which discharges into the Dyarubbin (Hawkesbury-Nepean River) system.

Click on an image to view Lawson, Ridge and Cataract Creeks.

Sediments and siltation

Lawson Creek is in a broadly healthy condition. However, the upper sections of the stream, above Adelina Falls, are permanently stressed by regular adverse urban impacts such as weed seed dispersal, weed growth and erosive stormwater flows.

These adverse impacts are often compounded by specific degradation events. Such an event occurred in 2009-10. A combination of heavy rains and massive stormwater flows, urban construction work, excessive vegetation clearing and a collapsed track led to extensive siltation of the creek, upstream of Adelina Falls. Water flow was reduced to a trickle and macroinvertebrate (water bugs) habitat was smothered in sand.

Bushcare Group members observed this situation and notified the BMCC Bushland Management Team. Contractors were employed to install a series of rehabilitative sediment control structures in the creek. These structures dispersed the sand flows and created pools of water which re-established bug and frog habitat. The collapsed track was remediated.

To some extent, this massive flow of sediments was a natural event, caused by very heavy rainfall. However, the concentration of stormwater flows in narrow pipes and gutters, the presence of hard surfaces and the removal of natural vegetation over many years resulted in this dramatically increased flow of water and sediments completely overwhelming Lawson Creek. 

The silted section of Lawson Creek is steadily recovering. Much of the sand has been dispersed and then naturally vegetated with locally indigenous plants. Also, much of the sand has commenced a long journey to the sea. Natural debris deposited by local bushland is helping to form riffles and deep pools, creating good water bug habitat. 

View the recovery of Lawson Creek between 2010 and 2018.

StreamWatch macroinvertebrate sampling in May 2019 revealed that bugs are starting to recolonise the silted section of stream. Mayfly nymphs (particularly sensitive to pollution) Damselfly nymphs, Dragonfly nymphs, Water Treaders (True Bugs) and Water Boatmen (True Bugs) were all present. See Archives/Lawson Creek recovery.

Erosion

Creek banks and their adjoining riparian areas are very sensitive to any form of continual disturbance, such as concentrated stormwater flows and overuse by humans. The soils are predominantly fine silt sediments that are very susceptible to erosion, if certain conditions arise.

The long-term impacts of unregulated disturbance, trampling, and excessive use can be ecologically devastating. Stretches of stream bank may become vegetatively denuded, resulting in severe erosion. Total bank collapse may occur. Weeds thrive in these disturbed situations. Indigenous animal habitat is destroyed.

Damage caused by dogs and their owners at Lawson Creek

Unauthorised use of Lawson Creek above Adelina Falls by numerous dogs resulted in a one hundred square metres section of Lawson Creek bank becoming severely damaged over the period 2016-2017. This is not an off-leash area. A large expanse of swamp and shrub vegetation was trampled and destroyed. Stripped of protective cover, soil has eroded, and tree roots have become exposed. Small trees have fallen. Quite possibly, exposed banks of the creek will start to collapse.

The BMCC Bush Regeneration Team remediated the damage by brushmatting the affected area. The team placed layers of cut, natural vegetation over the bare areas. However, it will take years for the natural vegetation to recover.

Unfortunately, by 2023 the same area had again become severely degraded, due to unauthorised dog use. Dogs trample the vegetation when they access the creek. An increased area of vegetation has been destroyed, leaving soils exposed to erosion. Looks ugly too. See Archives/Articles/11. Conservation Society Hut News 2023 Lawson Creek degradation.

This land is a public asset, managed by Blue Mountains City Council, on behalf of all residents. The South Lawson Waterfall Circuit walking track (Lawson Creek, Cataract Creek, Adelina Falls, Junction Falls and Cataract Falls) is not a dog off-leash zone. Dogs must be on a leash, at all times. There is a large (approximately 4ha) Blue Mountains City Council dog off-leash area at Wilson Street, Lawson, equipped with dog play facilities. Dogs walking outside the Wilson Street off-leash area must be fully supervised, and conducted on a leash.

———

(The South Lawson Park Bushcare Group website, including text and analysis, is managed by Peter Ardill. Australian Copyright Act 1968 applies. Text, media and all other contents of this site are subject to copyright. Many thanks to the members of South Lawson Park Bushcare Group, BMCC Bushcare Officer and Second Minutes Hours Productions for their contribution of images to this website)