Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

A perspective on the need for assessing the fish transfer risk associated with pumped hydropower schemes (#148)

Elizabeth Pope 1 , Lee J Baumgartner 2 , Craig A Boys 3 , Dean M Gilligan 4 , Luiz GM Silva 2 , Brett Pflugrath 5 , Nathan Ning 2
  1. Snowy Hydro Limited, Tumut
  2. Charles Sturt University, Thurgoona, NSW, Australia
  3. NSW Department of Primary Industries, Nelson Bay
  4. NSW Department of Primary Industries, Batemans Bay
  5. Pacific Northwest National Laboratory, Richland, Washington, USA

Pumped hydropower is becoming a more popular form of power generation in many countries.  A main benefit of pumped hydropower is that it can take advantage of existing impoundments and continuously cycle water between the upper and lower impoundment. However, in situations where pumped hydro leads to cross-catchment transfers of water, operation of the station can introduce the risk of unintended biotic transfers between the headwater and tailrace; especially for fish. For instance, fish that are present in tailwater reaches, and not upstream may introduce a risk to upstream populations. The degree of potential impact would be dependent on the (a) population ecology of the head and tailwater fisheries; (b) operation and design of the turbine and pumping scheme; (c) habitat and thermal regime of the two reservoirs; and (d) whether mitigation options are incorporated into the system design. Snowy 2.0 — a proposed 2000 MW pumped hydropower facility in south-eastern Australia — is a major national infrastructure project which will augment Snowy Hydro Limited's existing hydropower output. It is possible that operation of the pumped hydropower station may introduce a risk of invasive species transfer from the tailrace to the headwater reservoir. A multi-factor risk assessment was performed to assess the transfer likelihood. It was quickly evident that limited information on the ability of fish to withstand conditions that are likely through the development, and the lack of existing similar developments, made it difficult to accurately estimate the likely risk of successful fish transfer using desktop investigations alone. As a result, laboratory and field experiments were proposed to fill any remaining pertinent risk-related knowledge gaps with empirically-based evidence.