Trevallyn Dam
| Company type | Dam |
|---|---|
| Industry | Hydroelectric energy |
| Founded | 1955 |
| Headquarters | Launceston , Australia |
| Products | Hydroelectric power, reservoir (Lake Trevallyn) |
The Trevallyn Dam, situated on the South Esk River within Launceston, Tasmania, plays a vital role in hydroelectric energy production. Constructed in 1955 as an integral component of the Trevallyn Hydro Electric Scheme, it creates the reservoir known as Lake Trevallyn.
Specifications
Lake Trevallyn is formed by a concrete gravity dam resting on Dolerite bedrock. The dam features a spillway with a height of 26.8 metres and a wall stretching 177 metres in length. The reservoir spans an area of and holds a water volume of . According to data from ANCOLD, the dam's wall reaches 33 metres in height and encompasses a volume of .
Water from the lake is channeled through a tunnel measuring 3.2 kilometres to the Trevallyn Power Station.
Lake Trevallyn
Extending toward Hadspen, Lake Trevallyn marks the beginning of rapids at the confluence of the Meander and South Esk River rivers. Its broadest section is Stephenson's Bay, which spans approximately 390 metres.
The lake’s perimeter includes the Launceston suburb of Blackstone Heights and part of the Trevallyn State Recreation Area. The surroundings consist of residential neighborhoods, farming land, and dry eucalypt forests.
Facilities
This area serves recreational purposes, particularly at Aquatic Point, where amenities such as a boat ramp, jetty, and ski-jump are available. A walking trail connects Aquatic Point with both the dam structure and adjacent recreational zones. Visitors can enjoy a viewing platform, parklands, and barbecue spots at the dam site. Boating and fishing activities are allowed throughout most parts of the lake, excluding zones near the dam and penstock intake.
Algal Blooms
During warm summer periods, Lake Trevallyn experiences algal blooms primarily due to elevated nutrient inputs from sewage treatment plants and fertilizers combined with stagnant water conditions and high temperatures. The dominant species involved is Anabaena circinalis, known for its potential toxicity; however, no toxic outbreaks have been documented within this lake. Since 2007, an ongoing monitoring initiative has been established to observe algal concentrations and notify relevant authorities when blooms arise.
Jellyfish
In 2009, populations of freshwater jellyfish Craspedacusta sowerbyi were identified in Lake Trevallyn near Blackstone Heights. These translucent, non-venomous jellyfish average about 2 cm in diameter and are thought to have been introduced by migratory birds arriving from China. They may contribute positively to the local ecosystem by preying on mosquito larvae. Following their discovery, some specimens were temporarily displayed at Launceston’s Queen Victoria Museum and Art Gallery (QVMAG).