7.2 Related initiatives
Lower Burdekin Groundwater Strategy Project
Over the last 20 years , increased irrigation in the Lower Burdekin has increased deep drainage into the underlying aquifer , resulting in a rise in groundwater levels . As groundwater levels rise towards the soil surface , water logging and increased salinisation of the root zone can occur as the rising groundwater saturates the soil profile and mobilises salts . Over time , this can lead to reductions in , or complete loss of , productivity .
The groundwater level is within 3m of the ground surface under approximately 15 per cent of the irrigated land within the study area ( DNRM , 2017 ). Shaw ( 2014 ) suggested that maintaining groundwater levels at or below 3m beneath the ground surface is sufficient to ensure that the crop root zone is not impacted by salinity or waterlogging 7 .
The Queensland Government recognises that a new approach is needed to manage rising groundwater levels to support current and future agricultural development and to minimise impacts on the environment , particularly the GBR lagoon . As a result , a Lower Burdekin Groundwater Strategy is being developed to set out an overarching plan to address rising groundwater and associated issues in the Lower Burdekin irrigation area to ensure the long-term health of the economy and environment . A discussion paper was developed in 2017 as the first step in the development of the strategy .
The discussion paper sets out four broad areas of management actions for consideration as part of an overall strategy to address rising groundwater and associated issues in the project area . They include :
� change to irrigation practices and supporting programs � operational actions � regulatory actions � incentive measures .
A draft strategy is expected to be available for consultation before the end of 2018 .
More recently groundwater harvesting has been introduced as a new product for the Burdekin Groundwater Management Area . Groundwater harvesting allows additional groundwater to be extracted when groundwater levels are above sets values . Establishment of these values considers :
� maintenance of an appropriate groundwater gradient toward the coast � sufficient groundwater levels to minimise risk of salt water intrusion from seawater � recognition of pre-development groundwater levels � groundwater targets to protect land and crops from potential waterlogging .
This process allows for a targeted approach to deal with rising groundwater levels that protects base groundwater entitlements .
The other significant initiative in the project area has been implementation of the 1 in 8 conjunctive use policy . This is a licencing policy that was implemented to allow access to additional supplies of groundwater . The policy involved granting a groundwater licence based on the volume of surface water held — for every 8ML of surface water held , 1ML of groundwater could be granted as a water licence . This policy was adopted following construction of the Burdekin Falls Dam and was based on the typical leaching ratio of the soils where it was calculated that for every 8ML of irrigation , 1ML would result in deep drainage to the aquifer .
7
Groundwater in the BRIA and recommendation to achieve sustainable groundwater management under a local management authority approach – Report to the Burdekin River Irrigation Area Irrigator ’ s Committee , April 2014 , Roger Shaw .
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