WQ Response to Geologic Variation

With altered precipitation regimes and variable groundwater resources being major factors affecting water quality, we initiated a project which incorporated bedrock and surficial geology as well as stream discharge to explain variability in water samples within local areas. If you were to look at the geology maps within the Oromocto River watershed you would see vast differences between the South Branch and the North Branch of the Oromocto River combined with the Rusagonis Stream. The South Branch runs through a variety of rock formations from the Ordovician, Silurian, Devonian, and up to Late Carboniferous periods while the North Branch Oromocto and tributaries run almost exclusively through Late Carboniferous bedrock which extends in a northerly direction all the way to the St. John River. With differing abilities to buffer acidity and differing chemistry for redox reactions, exploring how the water quality in the two principal branches reacts to groundwater resources was done by sampling two or more streams of each surficial and bedrock geology type. By exploring the range of water quality within the two sub catchments and comparing and contrasting these variables with land use, discharge and seasonal fluctuations, it is possible to observe trends in the data both temporally and spatially.

降水格局改变与动态变化的地下水资源是影响水质的核心因素，为此我们启动了一项研究项目，整合基岩（bedrock）、表层地质（surficial geology）以及溪流流量（stream discharge）数据，以解析局域范围内水样的水质变异特征。奥罗莫克托河（Oromocto River）流域的地质图显示，其南支流、北支流与拉萨贡尼斯溪（Rusagonis Stream）之间存在显著地质差异。南支流流经奥陶纪（Ordovician）、志留纪（Silurian）、泥盆纪（Devonian）直至晚石炭世（Late Carboniferous）的多种岩层；而奥罗莫克托河北支流及其支流几乎仅分布着向北延伸至圣约翰河（St. John River）的晚石炭世基岩。由于不同岩层的酸缓冲能力与氧化还原反应（redox reaction）化学特性存在差异，本研究针对每一类表层与基岩地质类型布设2条及以上溪流进行采样，以探究两条主支流的水质对地下水资源的响应规律。通过解析两个子流域的水质变化范围，并将这些变量与土地利用、溪流流量及季节波动进行对比分析，可从时间与空间两个维度揭示数据集的变化趋势。