Journal of the Australian Native Plants Society Canberra region (Inc)

Water harvesting in a Canberra urban park – A community led project in Bragg Street Park, Hackett

By Chris Mobbs

May, 2026

An open woodland

Bragg Street park is one of five open spaces in Hackett (area of 1 ha). It is largely natural open woodland with mostly native and some exotic trees, and a ground cover of native grasses and herbaceous species, and introduced grasses and weeds. Mowing is done monthly. There is no artificial watering. About 140 species of plants have been recorded — 96 native and the rest exotic — neighbouring Mt Majura-Ainslie Nature Reserve has 530 species. There are about 50 large eucalypts — some with hollows. Eucalyptus blakelyi (Blakely’s red gum) and Eucalyptus melliodora (yellow box) are the most common, with some Eucalyptus mannifera (brittle gum) and Eucalyptus polyanthemos (red box). There is one Eucalyptus bicostata (southern blue gum). Non-native trees include Fraxinus spp. (Raywood Claret ash) and Quercus borealis (red oak).

Residents take action

In 2016, several residents noted that there were many small self-seeded eucalypts being cut by mowing. Residents decided to protect these by placing staking around 30 plants. This worked — today there are about 65 small eucalypts ranging in height from 0.5 to 5m. This initial action led to the formation of the Bragg Street Park Volunteers Group in 2018 which now has about 50 residents as members. The group is registered with the ACT Government Urban Parks and Places Volunteering program.

Our group developed a plan in 2018 which set out our vision for improving the vegetation and recreational facilities in the park. In 2018 we applied for a grant ($4,500) from Nature Play Grants Program to build a small scale nature play area near the existing swings. This proposed the provision of rocks and logs for sitting and stepping logs, but was unsuccessful. In late 2018, the ACT Government held a Better Suburbs Play Spaces Forum as part of the Better Suburbs program. This Forum, with community representatives from across Canberra, made recommendations to improve play spaces. These included a notional $5,000 to the Bragg St Park for some minor natural features. In March 2019 contractors installed 12 boulders near the swings, and two sets of three large logs. In September 2019 the Government gave the group, 60 native plants which the group planted on the Brennan St side in an area called a No Mow Zone. These and many of the self-seeded eucalypts and wattles were mulched with woodchips provided by the Government.

Flooding blocks stormwater drain

In 2019, Canberra’s rainfall was about 40% below average (648mm/year) and in 2020, was 790mm. During heavy rain, water would rush across the surface taking with it soil and detritus into a drain that runs through the middle of the park. This drain goes under backyards of houses in Bragg and Brennan Streets below the park. The drain would often block and overflow, causing flooding in several gardens and garages in these streets. A number of volunteers recognised the need to reduce run-off. ICON Water cleaned-out the drain but advised that reducing run-off in the park was not their responsibility.

Swales help harvest water

One resident (Tony Steel) recommended that reducing run-off would be achieved by earthworks in the form of swales. Swales are mounds of soil built across a slope with the aim of capturing water and directing it into the sub-soil, rather than letting it run across the surface. The increased water in the soil will greatly benefit plants.

Priorities under the 2020–21 Nature in the City grants program were to fund on-ground projects that created or supported living infrastructure within urban areas including projects:

“reclaiming a degraded area and developing its potential for supporting living infrastructure, including street verges;
improving soil quality, health and water penetration;
improving survival rates of existing living infrastructure, including at-risk young, mature and hollow-bearing trees.”

To assist prepare our application we contacted the Paul Barnett Design Group (O’Connor) a well-known landscape designer group. He referred us to Paul Totterdell of Sustainable Organic Solutions who has built swales in the ACT and NSW for over 25 years. e.g Orana Steiner School at Weston Creek, Aranda Primary School, and Majura Primary at Watson. He quoted $9,100 to build seven swales. The group applied for and received a grant of $9,100 under the program.

From 5–11 August 2021, they built seven swales (1535 metres long, 3–4m wide, by 1 metre high) across the contours from the upper end to the lower end of the park. Locations shown on aerial photo.

Constructing a swale

Topsoil was first dug out to around half a metre deep i.e. like a long bowl to form the swale shape. Channels about 50cm wide by 70cm deep, were then dug along the lower part of each swale and then filled with sand to improve the infiltration of water entering the ground. Soil from the channels was used to create the front walls and cover the sand. Rocks, about 3–6 times the size of a football were placed on top of 3–4 sand ‘plugs’ placed along each swale.

Putting plants on the swales

The ACT Government donated a variety of native species which the group planted on the swales. Priority has been for species native to Mt Majura/Ainslie or native species listed in the ACT Government’s Municipal Infrastructure Standards Part 25 Plant Species for Urban Landscape Projects. The group received several Adopt a Park grants which we used to purchase more plants to put in the swales and two no-mow zones ($3,000 in 2021–22, $3,300 in 2022–23 and $2750 in 2024 –25).

The plants on the walls of the swales have grown very well, but some in the base of the swales died due to waterlogging — too much water following construction. Canberra’s average rain (Canberra airport) is around 600mm but from 2021–2023, rain was above average:

2021 — rainfall 50% above average — 5th wettest year on record 912mm
2022 — 892mm
2023 — 711mm
2024 — 567mm
2025 — 530mm

Varying soils

Although the park is a relatively small area, the soils are variable. Swales 1 and 2 at the top of the park have reasonable top soil, whereas swale 6 is mainly heavy clay, while swales 5 and 7 are mostly red loam/clay. Given this variation we experimented with different species on the swale walls:

Swale 1 — Correa dusky bells and Themeda triandra (kangaroo grass)
Swale 2 — Veronica perfoliata — diggers speedwell
Swale 3 — Hardenbergia violacea
Swale 4 — Lomandra longifolia — spiny head matrush
Swale 5 — Grevillea juniperina — molonglo
Swale 6 — Hardenbergia violacea
Swale 7 — transplanted Chrysocephalum apiculatum (everlasting daisies) from mown areas in the park

Some of the swales (swale 3, 4 and 6) held water during the wet 2022 spring. This drowned some of the plants in the base of the swales including Cassinia longifolia, Dodonaea viscosa, Kunzea parvifolia, and Solanum linearifolium. But others survived — Indigofera australis, Acacia dealbata, Acacia rubida Hardenbergia violacea, Lomandra longifolia, Pomaderris betulina and Leptospermum lanigerum.

Children like to explore interesting landscapes and we noted some liked to walk along the tops of the swales, therefore we put the plants on the sides to avoid them being trampled. Woodchips have been placed across all swales to help keep weeds out.

Many self-seeded eucalypts have grown up

In addition to the eucalypts that have grown outside of the swales there have been many growing in the swales — especially on swale 3 — around 25 Blakelyi’s red gums some now 3m high.

Herbaceous and grass native species

There are over 40 native herbaceous and grass species. The two no-mow gardens have been used to promote growth of these. Some were transplanted from elsewhere in the park including:

Bulbine bulbosa lily
Eryngium ovinum blue devil
Wahlenbergias blue bells
Wurmbea dioica early nancy
Glycine tabacina
Goodenia pinnatifida

Calotis anthemoides (Chamomile burr daisy) covers a small patch about 15x15m on very hard soil near swale 5. It grows about 10cm high with fine bright green leaves. In October it bursts into bloom with many small yellow and white daisy flowers — forming a colourful

carpet in this area. It dies back in the dry but grows back after rain. We were able to stop this patch being mowed when in flower in 2022.

Lizards and frogs appear

Between September and December 2023 a bearded dragon was often seen on the Brennan St side of the park sunning itself on the woodchip pile, trees and rocks on the swales. In September 2024 a dragon (possibly the one from 2023) was seen in the no-mow garden on Brennan Street. In November 2024 four small ones had been seen in the park (perhaps offspring of the lizard that moved into the park in 2023?).

The large amounts of rain during spring 2022 filled the swales, creating the perfect habitat for frogs. Frogs were not present before the swales were built. Frogs began calling in August 2022 and continued through to early November 2022, with five species recorded:

plains froglet — Crinia parinsignifera
common eastern froglet — Crinia signifera
striped marsh frog Limnodynastes peronii
spotted marsh frog Limnodynastes tasmaniensis
whistling tree frog Litoria verreauxi

The frogs were calling in spring 2023, 2024 but not in 2025.

A model for other urban parks

The park is on the cover of the ACT Government’s Stormwater management for community Groups (2025).

Chris Mobbs Convenor

Bragg Street Park Volunteers Group Hackett

Email – mobbs.cb1@gmail.com.au

April 2026

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