Lake Meadowbank water infrastructure

Fletcher Pegus (email)

Our water resources team has been busy helping Hydro Tasmania to work with farmers during preparation for essential dam maintenance over the next couple of years.

Hydro Tasmania are Australia’s largest generator of hydro-electric power, producing about 9,000 gigawatt hours, enough to power 900,000 Australian homes and businesses. Hydro Tasmania’s assets include 30 power stations and 50 major dams. Pinion Advisory were engaged by Hydro Tasmania to undertake pump station assessments at properties adjacent to Lake Meadowbank in Tasmania’s Central Highlands.

Hydro Tasmania are required to carry out essential maintenance work on the Meadowbank Dam crest gates in February to April 2022 and February to April 2023. To facilitate this work, Lake Meadowbank’s water level needs to be lowered 2m and 6m throughout that time.

The Lakes level is generally kept relatively constant, within a 0.6m range, to achieve maximum power generation. However, its full operating range is 6m.

Landowners (primarily farmers) adjacent to Meadowbank Lake can install water infrastructure that operates within the 0.6m range, for agricultural and domestic purposes, but are encouraged by Hydro Tasmania to consider the full operating range when making personal and business decisions. This is important because Hydro Tasmania, as owners of the Lake Meadowbank asset, have the right to, and can manage Lake Meadowbank across its full 6m operating range at their discretion.

Hydro Tasmania also recognises the importance of Lake Meadowbank to the local agricultural community and wants to consider the potential impacts on users that would be adversely affected by the lowering of the Lake.

Pinion Advisory undertook a water infrastructure assessment of all 16 properties (54 pump sites) that pump from Meadowbank Lake for irrigation, stock, or domestic purposes. Information from this report was provided to Hydro Tasmania to identify requirements for farmers to continue their operations whilst the lake is lowered during periods of maintenance on the Hydro Tasmania infrastructure.

An initial site visit and was completed by Brock Nadler and Fletcher Pegus, to obtain information on all water infrastructure, discuss with landowners how they use their pumps, take photographs, and survey the height of the pumps (+/- 20mm). A second site visit was undertaken with Dave McLaren and Fletcher Pegus the following week when a trial drawdown of 2m was implemented by Hydro Tasmania. We were able to undertake a visual assessment and survey the water level at each location, to determine to impact of the draw down at each pump site.

This information, paired with bathymetric data provided by Hydro Tasmania, has been used by Brock to develop concept solutions and high-level cost estimates to upgrade the infrastructure at each pump-site. This will ensure that the farmers in the area can continue to operate their irrigation effectively when the Meadowbank Lake is operating at its full range, for maintenance or other reasons in the future.

Dave McLaren

Dave McLaren carrying our pump shed survey work to establish accurate elevation

Meadowbank Power Station

Aerial photo highlighting the agricultural region that uses water in Lake Meadowbank, upstream of the Power Station operated by Hydro Tasmania. This is also the primary source of Hobart’s drinking water with the main treatment plant some 10km downstream