Write a debate on dams are the best ways for utilization of river water?
Answers
Australia needs a strong agricultural sector for vibrant rural communities. Agricultural production in Australia relies heavily on good water management, in plants, in the soil and at the field and farm level.
Drought is a recurring Australian feature, and water security is therefore a key issue for many Australian farmers. Agriculture for the future needs smart solutions to manage water, and soil moisture, to increase the water use efficiency of the production systems.
Dams, due to their physical dimensions, store large amounts of water, but in the Australian environment also lose large amounts of water through high evaporation (particularly in summer) and possible seepage as was also identified by the Irrigation Futures CRC.
A quick back of the envelope calculation suggests that, on a typical summer day with up to 5 millimetres of water lost in evaporation, 1 hectare of water surface could evaporates 50,000 litres of water.
In addition, dams have a limited life span due to sedimentation and are known to have unintended upstream and downstream impacts.
Finally, while dams can provide some buffering of water supply in droughts, in the last Millennium drought this buffering clearly was insufficient as shown by the collapse in irrigated production in cotton and rice between 2000 and 2010.
More specifically in Northern Australia the development possibilities for dams was questioned by experts from CSIRO and the University of Melbourne, because the river flow is so variable in Northern Australia.
Better ways to manage waterThe green paper rightly states that Australia should be delivering a high value agricultural product that is seen as “green, clean and safe”.
In my opinion, this means that Australia requires smart solutions for managing water and drought on-farm, through better crop varieties, more efficient water application, smarter irrigation layouts, better on-farm data collection and interpretation, and more education and training.
This is currently being pursued on farm through reducing water inputs via drip and trickle irrigation, connecting nutrient and water management, better timing of applications, and increasing the use of new technology to save water on farm. This particularly requires easier-to-use technology and better on farm and hands-on training.
The green paper also rightly states: “water availability can also be increased by improvements in existing water infrastructure”. Clearly this is a much smarter way to go: continued investment in improving rural water infrastructure and the efficiency of irrigation enterprises, as well as continued focus on the water market.
The green paper also mentions groundwater augmentation and reuse. This remains a tricky subject, but with more information on groundwater and surface water interaction, there might be opportunities.
Water stored in groundwater is less susceptible to evaporation losses, but there are other problems related to water quality and recovery costs. In addition, over extraction of groundwater is a global issue, and does not create more water for production. However, this is an area that is smart to invest further work.