FAQs

The mouth of the New Town Rivulet has been heavily modified since European settlement. The eastern bank beyond Marine Esplanade is largely reclaimed wetlands and historically used as a landfill site.  The rivulet was turned into a stormwater channel and concrete walls built along its embankment more than 50 years ago.  More recently an artificial headland was created on the eastern bank of the mouth using reclaimed sediment.  The weir was installed in 1998 to support remediation of New Town Bay, reduce sediment build-up at the mouth of the rivulet and to enable the New Town Bay Rowing Club launch boats at low tide. 

A 2021 review of the concrete walls and weir identified structural issues that require rectification. The recommended approach was to remove the concrete walls and naturalise the embankments with rock and vegetation to prevent erosion. 

Multiple options were considered for the weir including removing it, but modelling indicates the weir helps prevent the accumulation of sediment at the mouth of the rivulet, especially during large floods, as occurred in 2018. Removal of the weir would require excavation and disposal of large volumes of contaminated sediments at considerable cost and would likely reduce the amenity of the area for local residents.

Instead, the weir will be retained and flow issues will be addressed to prevent localised erosion. This will require the construction of concrete abutments on either side of the weir to prevent bypass flows. Rock protection will also be added upstream and downstream of the weir to help prevent erosion during high water flows.

Flooding in the area has previously occurred during high flow events. Impacted areas include Risdon and Albert roads adjacent to nearby parks. 

Flood modelling for this project design demonstrates flood levels outside the rivulet will be reduced due to increased flow capacity downstream of the Queens Walk Bridge. This has been achieved by removing large volumes of material from the embankments. However, this work will not prevent future flooding of the embankments, and so landscaping will be used to help stabilise the rivulet embankments and prevent erosion during flood events. 

New maintenance access ramps will allow for more regular removal of accumulated sediment downstream of the Queens Walk Bridge. Future sediment accumulated upstream of the weir will need to be removed on a regular basis to prevent flooding.

The project site will be fenced off during the construction period. Excavators will be used along the rivulet embankment to remove concrete, excavate materials and position rock.  To minimise noise impacts there will be restrictions on when machines can be used onsite:

1. Monday to Friday: 7am and 6pm
2. Saturday: 8am to 6pm
3. Sunday: 10am to 6pm. 

Water will be used to suppress dust and vehicle movements to and from the site will be minimised by reusing excavated material where possible instead of bringing in new material. Most of the excavation will occur in the northern area of the site, near the mouth of the rivulet.

Material excavated from the rivulet embankments will be reused where possible for landscaping on either side of the rivulet mouth. This landscaping will be up to 1.5m high and capped with clean fill, mulch and then planted out. 

Recent testing of soils from the proposed excavation site indicates that while there is some contamination associated with historic landfill and other site activities, these are classified as ‘low risk’ and may be reused on site.  The City of Hobart will prepare a management plan and liaise with EPA Tasmania regarding the management of contaminated materials. 

Formalised parking is proposed for both sides of the rivulet, with five car parks planned for the existing, informal car park area off Risdon Road, including space for disabled parking.

Boulders will be installed along Marine Esplanade to help protect mature eucalypts that are showing some stress from current informal parking.

Twenty one formal car parking spaces will be created along Marine Esplanade,  in addition to existing parking near the New Town Bay Rowing Centre.

Almost 10,000 native plants and trees will be established along the rivulet to help stabilise sediment build-up, for flood mitigation and to help restore the natural values of the area, attracting birdlife and improving estuarine biodiversity.  

Twenty three existing mature blue gums along Marine Esplanade will be protected, providing important habitat for the threatened swift parrot. Turf and mulch surfaces will also be installed to improve the amenity of the area.  One threatened flora species, sea clubsedge (Bolboschoenus caldwellii), has been identified in this area. Construction will be managed to protect existing clubsedge and more than 900 new clubsedge plants will be planted along the rivulet.