Identifying groundwater discharge zones to lakes is important because the groundwater system can contribute a significant flux of water and solutes and potentially influence lake chemistry and ecology. We present a new instrument, Temperature Mapper (TM), to map groundwater discharge zones in lakes via temperature anomalies along the lake bottom, tested in Lake Constance at 2 former sand and gravel extraction sites. TM is essentially a 4 m wide sled with an array of 19 high-resolution sensors attached to an aluminum lattice towed along the lake bed behind a boat. It is able to map spatial temperature patterns representing groundwater discharge zones at a resolution of 20 cm laterally and 2.5 m in path direction. We conducted 2 field campaigns in February 2016 and February 2017, during which TM identified several temperature anomalies interpreted as groundwater discharging zones. Radon-222 was also analyzed at selected locations as an independent indicator of groundwater discharge. Overall, when comparing the different methods and different years, we observed similar spatial patterns of preferential groundwater discharge. TM offers a useful qualitative tool to identify and map potential groundwater discharge zones in lakes or coastal areas that can then be further studied by more quantitative, small-scale methods such as chemical tracers or seepage meters.

确定地下水向湖泊的排放区很重要，因为地下水系统会贡献大量的水和溶质，并可能影响湖泊的化学和生态。我们提出了一种新的仪器Temperature Mapper（TM），用于通过沿湖底的温度异常来绘制湖泊中的地下水排放区域的地图，并在康斯坦茨湖的2个以前的砂石采石场进行了测试。TM本质上是一个4 m宽的滑板，带有19个高分辨率传感器阵列，该传感器附着在沿着船后湖床拖曳的铝格上。它能够绘制代表地下水排放区的空间温度模式，其横向分辨率为20 cm，路径方向为2.5 m。我们在2016年2月和2017年2月进行了2次野战，在此期间，TM确定了几个解释为地下水排放带的温度异常。还对选定位置的Radon-222进行了分析，作为地下水排放的独立指标。总体而言，当比较不同方法和不同年份时，我们观察到优先地下水排放的相似空间格局。TM提供了一种有用的定性工具，可以识别和绘制湖泊或沿海地区潜在的地下水排放区，然后可以通过更定量的小规模方法（例如化学示踪剂或渗漏仪）进行进一步研究。我们观察到相似的优先地下水排放空间格局。TM提供了一种有用的定性工具，可以识别和绘制湖泊或沿海地区潜在的地下水排放区，然后可以通过更定量的小规模方法（例如化学示踪剂或渗漏仪）进行进一步研究。我们观察到相似的优先地下水排放空间格局。TM提供了一种有用的定性工具，可以识别和绘制湖泊或沿海地区潜在的地下水排放区，然后可以通过更定量的小规模方法（例如化学示踪剂或渗漏仪）进行进一步研究。