Three-dimensional geological and groundwater flow models of a submarine groundwater discharge (SGD) site at Hanko (Finland), in the northern Baltic Sea, have been developed to provide a geological framework and a tool for the estimation of SGD rates into the coastal sea. The dataset used consists of gravimetric, ground-penetrating radar and shallow seismic surveys, drill logs, groundwater level monitoring data, field observations, and a LiDAR digital elevation model. The geological model is constrained by the local geometry of late Pleistocene and Holocene deposits, including till, glacial coarse-grained and fine-grained sediments, post-glacial mud, and coarse-grained littoral and aeolian deposits. The coarse-grained aquifer sediments form a shallow shore platform that extends approximately 100–250 m offshore, where the unit slopes steeply seawards and becomes covered by glacial and post-glacial muds. Groundwater flow preferentially takes place in channel-fill outwash coarse-grained sediments and sand and gravel interbeds that provide conduits of higher hydraulic conductivity, and have led to the formation of pockmarks on the seafloor in areas of thin or absent mud cover. The groundwater flow model estimated the average SGD rate per square meter of the seafloor at 0.22 cm day⁻¹ in autumn 2017. The average SGD rate increased to 0.28 cm day⁻¹ as a response to an approximately 30% increase in recharge in spring 2020. Sensitivity analysis shows that recharge has a larger influence on SGD rate compared with aquifer hydraulic conductivity and the seafloor conductance. An increase in recharge in this region will cause more SGD into the Baltic Sea.

已开发了波罗的海北部汉科（芬兰）的海底地下水排放（SGD）站点的三维地质和地下水流模型，以提供地质框架和估算SGD进入沿海海域的工具。所使用的数据集包括重力，探地雷达和浅层地震勘测，钻探测井，地下水位监测数据，现场观测以及LiDAR数字高程模型。该地质模型受晚更新世和全新世沉积物的局部几何形状的约束，这些沉积物包括耕作，冰川粗粒和细粒沉积物，冰川后泥浆以及沿海和风沙沉积物粗粒。粗颗粒的含水层沉积物形成了一个浅岸平台，该平台在海上延伸了大约100–250 m，该单元向海陡峭倾斜，并被冰川和冰川后的泥浆覆盖。地下水流优先发生在河道充水冲刷的粗粒沉积物以及砂砾砾岩夹层中，这些沉积物提供了较高的水力传导率导管，并导致在稀薄或无泥覆盖区域的海底形成了斑点。地下水流模型估计了每天每平方米海底平均SGD速率为0.22 cm2017年秋季为⁻¹。平均SGD速率增加到0.28 cm天^-1，以响应2020年春季补给量增加约30％。敏感性分析表明，与含水层的水力传导率和水力传导率相比，补给对SGD速率的影响更大。海底电导。该地区补给的增加将导致更多的SGD进入波罗的海。