All irrigation developments inherently carry a salinity risk, due to an unavoidable change in the water and salt balance. The time frame in which either land or water salinity will develop is driven by the ability of the landscape to absorb the change of water and salt supplied. Factors that influence this are landscape attributes, such as the size of the unsaturated zone and its properties (permeability and drainage), management considerations (land-use changes, water application rate and crop water use) and climate variability (temperature and rainfall). This study assessed the risk of secondary salinity expression occurring in an irrigation area in the Condamine-Balonne catchment in southern inland Queensland, Australia. The objectives were to (1) define the depth, size and properties of the unsaturated zone and regolith, (2) define deep drainage rates for past, present and future land uses and (3) assess this information to calculate the risk that groundwater table rise may result in surface salinity expression. Data collected during field investigations was used to conceptualise the regolith architecture, undertake hydrogeological modelling, estimate the available moisture storage capacity of the unsaturated zone and model paddock deep drainage characteristics. The work identified that irrigation-induced deep drainage had started to mobilise salt stores in the unsaturated zone. It also identified connectivity between land management and salt discharges into the Condamine River. As the water supply for the scheme is scheduled to continue until 2030, there is a clear risk of the unsaturated zone moisture storage capacity being exceeded, leading to both land and surface water salt expressions.

中文翻译：

---

康达明河集水区利用处理过的煤层气水进行灌溉开发的盐度风险评估

由于水和盐平衡的不可避免的变化，所有灌溉开发都固有地带有盐度风险。陆地或水域盐度发展的时间范围取决于景观吸收水和盐供应变化的能力。影响这一点的因素是景观属性，例如非饱和带的大小及其特性（渗透性和排水性）、管理考虑因素（土地利用变化、用水率和作物用水）和气候变异性（温度和降雨量）。本研究评估了澳大利亚昆士兰州南部内陆康达明-巴隆集水区灌溉区发生次生盐度表达的风险。目标是 (1) 确定非饱和带和风化层的深度、大小和性质，(2) 定义过去、现在和未来土地利用的深层排水速率，以及 (3) 评估此信息以计算地下水位上升可能导致地表盐度表达的风险。实地调查期间收集的数据用于概念化风化层结构、进行水文地质建模、估计非饱和带的可用水分储存能力和模拟围场深层排水特征。研究表明，灌溉引起的深层排水已经开始调动非饱和带中的盐分储存。它还确定了土地管理和向康达明河排放盐分之间的联系。由于该计划的供水计划持续到 2030 年，因此存在明显超出非饱和区水分储存容量的风险，