The Dalby Sponge City Masterplan

Project statement

Dalby is a small rural town in the Western Downs Region of Queensland, around 2 hours west of Brisbane. It is located within the Myall Creek floodplain, and experiences high temperatures for the majority of the year. Dalby residents are very familiar with extreme flood and drought conditions, both of which effect the town’s economy as well as local ecology.
In response to these conditions, a sponge city conceptual approach was adopted. A sponge city is one designed to cope with excess rainfall by designing to significantly reduce the severity and frequency of flooding events, and mitigate the effects of drought. It enables an urban area to absorb excess water, including using efficient channelling and storage systems to counter the frequency of water shortages.
The sponge city approach creates a landscape that is more resilient to both flood and drought events, and was applied to Dalby using 3 typologies: sponges parks, artificial sinks, and green street ends. These typologies connect the entire town to creates a landscape/community that is resilient and adaptable. Instead of water being a weakness in the Dalby landscape, it becomes an asset and attraction.

sponge city concept

sponge parks

A sponge park serves as a “green sponge”, absorbing, storing, purifying, permeating, and replenishing groundwater in the rainy season to advance the urban hydrological cycle, regulate micro-climates, and improve the urban environment by maintaining or increasing urban biodiversity. Stored rainwater can be recycled for use in the dry season, allowing water sensitive towns that struggle with droughts to have a backup water supply system.

artificial sinks

Artificial sinks collect excess surface water, doubling as small ponds for people to enjoy in the rainy season. During the dry season, these spaces can be used as lawns for events, sports, picnics, and relaxation.

green streets

Green streets consist of vegetated kerbside bioswales and street-end bio-detention basins where runoff is filtered and collected via perforated under-drains, allowing it to flow into downstream waterways or into storage for reuse in the dry season

STRATEGIC MASTERPLAN

33 YEAR PLAN

The rationale for the phasing of this masterplan was based on the logic informing the selection of the locations for the sponge parks, artificial sinks, and green streets. Phase one begins in the higher ground of Dalby, as stopping and slowing water at these higher points will slow the velocity of water running through the town. Phases 2 and 3 move downhill through the town creating sponge parks and green streets that continue to mitigate the effects of excess water. Phase 4 involves the implementation of the artificial sinks along Myall Creek, at the lowest points in the town.

PHASE 1: A – Jandowae Precinct
This precinct is comprised of the primary road (Jandowae Road) connecting to Jandowae and a patch of under-utilized land, located next to a residential area. Jandowae road will become a part of the green streets network and the under-utilized land will transform into a sponge park.

PHASE 1: B – Blue Hills Precinct
This precinct contains several secondary roads that surround and connect from blue hills estate park to the bunya highway. These roads will become a part of the green streets network, while blue hills estate park will be designed into a sponge park

PHASE 2: A – Dalby Showgrounds Precinct
This precinct is made up of a patch of under-utilised land next to the Dalby showground and a secondary street named Bligh St. these elements will again contribute to the existing green street network and sponge park implementations.

PHASE 2: B – Diplock Precinct
This precinct contains 2 major roadways within the town, these being Warrego highway and Moonie highway, both of which cut straight through Dalby. The precinct is also home to Diplock park, a value youth park that contains a stake park. These roads will become a part of the existing green streets network and Diplock park will become another sponge park, with special consideration into its important as a youth park to the town.

PHASE 2: C – Mary Precinct
The precinct is comprised of several secondary residential streets and the bunya highway, along with a patch of under-utilized land next to some larger residential properties. This patch of land will be transformed into a larger sponge park, while the road within the precinct become a part of the existing green streets.

PHASE 2: D – Myall Creek East
This precinct is located along the east side of the Myall Creek and is currently not used or utilized for anything in the town. This creates a perfect location for the implementation of an artificial sink.

PHASE 2: E – Bunya Park Precinct
This precinct is comprised of the bunya park racecourse and recreational sporting fields, along with several secondary roads and the Warrego highway. The roadways will become a part of the green street network and the perimeter of the bunya racecourse and sporting fields will be transformed into smaller interventions of a sponge park, making sure to not disturb the current activities that take place on site.

PHASE 3: A – Moonie Precinct
This precinct is made up of the Monnie highway and several smaller residential streets, along with a patch of under-utilized land that backs off both industrial and residential lots. The streets will become a part of the existing green streets network, while the patch of land will be converted into a sponge park.

PHASE 3: B – William’s Precinct
William’s precinct contains the Monnie highway and several smaller residential streets, along with two small parks on opposite side of the Moonie highway, these being William’s Park and Lions Park. The roads will become a part of the existing green street network, that has been established in other phases and stages of this masterplan, and the parks will become smaller interventions of sponge parks

PHASE 3: C – Thomas Jack Precinct
This precinct is comprised of the Warrego highway and several other residential streets, along with Thomas Jack Park, which is located close to the town centre. The roads will become a part of the existing green street network and Thomas Jack Park will become a more civic sponge park because of its location within Dalby.

PHASE 3: D – Bell Precinct
This precinct is comprised of secondary residential roads and a small park named Bell Park. The roads will become a part of the existing green streets network, while the park will be transformed into smaller inventions involved in a sponge park.

PHASE 3: E – Myall Creek Parklands
This precinct is located along the east side of the Myall Creek and is currently not used or utilized for anything in the town. This creates a perfect location for the implementation of an artificial sink.

PHASE 3: F&G – Southern Dalby Parklands
This precinct is comprised of the Warrego highway and several other residential streets, along with the Southern Dalby Parks. The roads will become a part of the existing green street network and the parks will all consist of interventions of sponge parks.

PHASE 4: A – Anderson Precinct
This precinct is made up of several residential and industrial streets, along with Anderson Park and the west side of the Myall Creek Parklands. The roads will become a part of the existing green streets implemented as a water management technique and the parks, along with any under-utilized green fields located on the creeks edge, will implement the artificial sinks, widening the creek when it rains

PHASE 4: B – Duffy’s Precinct
This precinct is comprised of mainly residential streets, along with a large parkland that runs down Myall Creek called Duffy’s Green. This parkland is a location for serval artificial sinks and space for densely vegetated areas, all of which help to mitigate flooding within Dalby

PHASE 4: C – Golf Course East
This precinct Is comprised mainly of parklands that are a part of the Golds Golf Course within Dalby, along with some residential streets. These streets will become a part of the existing green street network and the boundary allocated in the masterplan will be transformed in a location for artificial sinks.

PHASE 4: D – Golf Course West
This precinct Is comprised mainly of parklands that are a part of the Golds Golf Course within Dalby, along with some residential streets. These streets will become a part of the existing green street network and the boundary allocated in the masterplan will be transformed in a location for artificial sinks.

THOMAS JACK PARK – DETAILED DESIGN

SPONGE PARK AND GREEN STREETS

Thomas Jack Park acts as a sponge park within the Dalby masterplan. It incorporates elements for water management as well as for the needs of an urban civic space. The town and the park’s history is used as a further driver for the park design.
Thomas Jack Park acts as a sponge through the waterplay and creek system. The entire site is regraded to slope down from the northwest, diverting excess rainfall into the creek. The creek is heavily vegetated allowing the water to soak into the land to create a greener park. The creek carries the water through the site and into an underground water tank, which can detain it for future use during the dry season. This water can also be pumped from the tank, through the waterplay system and into adjacent gardens.
The Park also fulfils the community need for human interaction with the inclusion of a playground, BBQ area, waterplay system and an open lawn for active and passive recreation. It also retains the existing information centre and amenities
The park design is strongly influenced by the legacy of Thomas Jack, the Mayor who changed the face of Dalby between 1930 – 1950. He implemented formal road and pathway systems, new lighting and water networks, street trees and recreational grounds. These elements shaped this design for Thomas Jack Park, inspiring the inclusion of treelined pathways and a new water system and evening light shows representing the effects Thomas Jack had on the streetscape, and the water and light network in the town and the implementation new recreational grounds.

DUFFY’S GREEN – DETAILED DESIGN

ARTIFICIAL SINKS AND GREEN STREETS

Duffy’s Green acts as an artificial sink within Dalby, surrounded by green streets. The artificial sinks placed within Duffy’s Green allow water to build up without overflowing into residential and commercial areas during heavy rainfall. It creates a landscape that is accessible in all-weather conditions: in the rainy season pedestrian routes run along the top of the sinks and a sky walk runs along the creek. These are accessible even when the sinks are full. In the dry season the sinks can be utilised for recreational uses like events, sports, and relaxation. The sinks contain terraced concrete steps in a contrast of hard and soft surfaces which is resilient to water intrusion when the sink does fill up. The implementation of new densely vegetated areas allows water to be absorbed naturally into the soil encouraging vegetation to thrive, creating a greener Dalby. Duffy’s Green provides people unique experiences within the site, and has a significant impact on how the town tackles the extremities of flood and drought.