Waterways

River Derwent & it’s Tributaries

Nearly 40% of Tasmania's population lives around the estuary's margins and the Derwent is widely used for recreation, boating, recreational fishing, marine transportation and industry [1].

Most of Hobart's water supply is taken from the lower River Derwent [1].

The Lower Derwent suffers from high levels of heavy metal contamination in sediments. The Tasmanian Government-backed Derwent Estuary Program has commented that the levels of mercury, lead, zinc and cadmium in the river exceed national guidelines. In 2015 the program recommended against consuming shellfish and cautioned against consuming fish in general. Nutrient levels in the Derwent between 2010 and 2015 increased in the upper estuary (between Bridgewater and New Norfolk) where there had been harmful algal blooms [2].

[1] Derwent Estuary and its catchment". Department of the Environment. Australian Government.

[2] Shannon, Lucy (23 April 2015). "River Derwent: Heavy metal contamination decreases, effluent increases, report finds". Australia: ABC News.

Plenty River

The Plenty River has long been identified as a priority river within the Derwent Catchment, on which to focus rehabilitation actives as its upstream from the Bryn Estyn water intake point [3].

The Plenty River provides water for drinking, agriculture and the historic Salmon Ponds [3].

Threatened animals are found in the Plenty Catchment - including the Tasmanian devil, Platypus, Eastern-barred bandicoot, Wedge-tail eagle, White-bellied Sea-Eagle, Grey Goshawk, and a number of native fish species.

The 2019 Plenty River Catchment - Rivercare Action plan developed multiple urgent action items to protect the river. These included

  • Minimising introduction of artificial inputs such as compost

  • Maintain mature high conservation forest for threatened fauna species

  • Monitor and enforce water use

  • Minimise bare ground cover

  • Enforce machine hygiene practices and wash down standards

  • Encourage best practice chemical use

  • Raise awareness for impacts of waste dumping

[3] Plenty River Catchment Rivercare Action Plan December 2009.

Plenty River Pollution event 2020

A alleged pollution spill event in September 2020. This event is “is alleged to have been from a farm containing a commercial composting facility that is adjacent to the Plenty River. This composting facility is regulated by the EPA under Permit No. 162/09, with Permit conditions varied by Environment Protection Notice No. 8894/1.” [4]

An EPA and Department of Primary Industries (DPIPWE) investigation found pollutants in the river resulted in the deaths of 100,000 brown trout fry, 12,000 rainbow trout fry, 43 brook trout broodstock and 23 display fish at the Salmon Ponds trout hatchery, which is a few kilometres downstream from the commercial composting facility [5].

Plenty River protection is vital

UPAGI resonates the concerns voiced by the Derwent Estuary Program, and the authors of the Plenty Rivercare action report - Derwent Valley Council, Southern Water (now TasWater), Inland Fisheries, Greening Australia, Hydro Tasmania & Salmon Ponds.

We call on those with the power to protect the Derwent & Plenty Rivers to do so.

Commercial composting facilities, land spreading waste, or feedlots are not appropriate along the Plenty River or its tributaries.

UPAGI will continue to advocate for the health of the waterways in the Plenty region.