Land use and climate change effects on water quality and water quantity are well documented globally. Most studies evaluate individual factors and effects, without considering the interrelationships between land use, climate, water quality, and water quantity. This study provides an integrated assessment of the cumulative effects of climate change and potential open-pit coal mining on streamflow and water quality in the Oldman River Basin, Alberta, Canada. A hydrological model was developed that incorporates estimates of future selenium loading, water use, and projected changes in air temperature and precipitation to evaluate changes in water quantity and quality. Model results indicate that estimated selenium concentrations, absent any attenuation, are likely to be substantially above most water quality guidelines and strong reliance on mitigation technologies would be required to maintain adequate water quality in the watershed if mine development were to take place. Streamflow is sensitive to changes in climatic conditions, and modelling results suggest there are likely to be increases in winter flow, earlier peak flow, and reductions in flow during the summer and fall months under the climate change scenarios. These changes can have direct impacts on the degree of selenium dilution and more generally on aquatic habitat, ecosystem health, and socioeconomic needs. This study highlights that water management decisions may mis-evaluate the risks and tradeoffs of future mine development if they fail to adequately consider climate change and changing streamflow regimes and their indirect effects on water quality.

土地利用和气候变化对水质和水量的影响在全球都有很好的记录。大多数研究评估个别因素和影响，没有考虑土地利用、气候、水质和水量之间的相互关系。本研究对气候变化和潜在露天煤矿开采对加拿大艾伯塔省奥尔德曼河流域的水流和水质的累积影响进行了综合评估。开发了一个水文模型，该模型结合了对未来硒负载、用水量以及气温和降水的预测变化的估计，以评估水量和水质的变化。模型结果表明，估计的硒浓度，没有任何衰减，可能大大高于大多数水质准则，如果要进行矿山开发，则需要强烈依赖缓解技术来维持流域内足够的水质。河流流量对气候条件的变化很敏感，建模结果表明，在气候变化情景下，冬季流量可能会增加，峰值流量可能会提前，而夏季和秋季月份的流量可能会减少。这些变化会对硒稀释的程度产生直接影响，更普遍的是对水生栖息地、生态系统健康和社会经济需求产生影响。