Study Into Effects Of Plantations & Other Land Uses On Local Stream Flows
May 28, 1999 Tumut and Adelong Times
A new research project is being undertaken into the effects of pine plantations and other land uses on stream flows in the Tumut area.
"Stream flows records for the Murrumbidgee show that, even allowing for diversions from the Snowy River, there has been a significant increase in water yields from the Murrumbidgee catchment in the latter part of this century - a period during which significant pine plantation expansion has been taking place," State Forests' Softwood Plantations Division Planning Manager, Mr Dave Cromarty said.
"Scientists have always known that trees use water. In fact, this is one of the main reasons land care experts advocate tree planting. Trees can help control rising water tables, dry land salinity and stream bank erosion," he said.
Mr Cromarty said a joint CSIRO and State Forests' study at Red Hill Station near Adjungbilly, and studies in the other parts of Australia, confirmed that forest plantations use more water than cleared land and even slightly more than native forest. "The increased water yields from the Murrumbidgee are almost certainly due to the extensive clearing which has taken place during this century. This new study should allow us to quantify the balance between plantation and land clearing at the creek catchment scale," he said. "More importantly we will be able to accurately predict future impacts."
DLWC Catchment Manager at Tumut, Mr David Priem, said that the new study would also complement work being carried out by the Department on better understanding the relationship between vegetation and the water cycle. "We know that we need more trees in the landscape to better control land and stream degradation, but we need to know how to do this without compromising downstream water users' access to water, especially in the context of the State Government's Water Reform policy," Mr Priem said. Ideally I would like to see farmers more involved in developing plantations for themselves, as their water-use efficiency converts into dollars better than grass does."
Consultant hydrologist, Dr Rory Nathan, with Sinclair Knight Merz as been commissioned to conduct the new study, which analyses rainfall and stream flow records for both the Tarcutta Adjungbilly Creeks, dating back to the 1930's. The study funded by the State Forests with collaboration from the Department of Land and Water Conservation (DWLC) will also utilize aerial photographs and State Forests' management history records track land clearing and plantation establishment.
"We are confident that this study will not only add to our understanding of this important issue but allow us to model the effects of water yields of new plantations in any particular area," Mr Cromarty said.
In order to address some of the concerns in the community about water yields, State Forests in compiling a public information brochure outlining the results of recent research including the Red Hill study.