Assessing in-situ physico chemical parameters variability of springs in mid-hill region of Nepal

Springs function in the hydrological cycle as natural outflows for groundwater systems and provide reliable potable water for communities. This study evaluates the physico chemical characteristics of 168 perennial springs that fluctuate seasonally across various geological settings (carbonate and non-carbonate dominant lithology), landcovers (cropland, forest, grassland), and elevation categories (Classes I, II, III) within the Seti Khola Watershed in the mid-hills of Nepal. It focuses on on-site physico chemical measurements, including electrical conductivity, total dissolved solids, pH, oxidation-reduction potential, dissolved oxygen, and temperature. Primary data from field measurements of spring attributes and remote sensing, including Landsat-8 OLI satellite imagery, examined the relationship between land surface and spring water temperature. Results show higher precipitation during the wet season dilutes solutes, enhancing dissolved oxygen levels, while the dry season’s higher evaporation rates concentrate solutes. The study highlights variable pH levels in non-carbonate regions, correlating with lower oxidation-reduction potential values. Carbonate terrain promotes stable and higher pH and oxidation-reduction potential values. Higher elevations correlate with lower temperatures and varying landcover, affecting thermal regimes. Seasonal interplay highlights the importance of fundamental hydrogeochemical characteristics in the context of natural processes and anthropogenic influences.

泉在水文循环中作为地下水系统的天然排泄通道，为社区提供可靠的饮用水源。本研究对尼泊尔中部丘陵区塞蒂科拉流域内168处随季节动态变化的常年泉（perennial springs）开展理化特征评估，这些泉分布于不同地质背景（以碳酸盐岩、非碳酸盐岩为主的岩性）、土地覆被类型（耕地、林地、草地）以及海拔等级（I、II、III类）区域。
本研究聚焦于原位理化测量指标，包括电导率（electrical conductivity）、总溶解固体（total dissolved solids）、pH值、氧化还原电位（oxidation-reduction potential）、溶解氧（dissolved oxygen）与水温。研究依托野外实测泉类属性所得的原始数据，以及包括陆地卫星8号OLI（Landsat-8 OLI）卫星影像在内的遥感数据，分析了地表与泉水温度之间的关联。
研究结果表明，湿季较高的降水量会稀释水体溶质，提升溶解氧含量；而干季较高的蒸发速率则会浓缩水体溶质。本研究指出，非碳酸盐岩区域的pH值波动幅度较大，且与较低的氧化还原电位值呈相关关系；而碳酸盐岩地貌则有助于维持更高且更稳定的pH值与氧化还原电位值。海拔越高，泉水温度越低，且土地覆被类型的变化会影响水体热状况。季节动态交互作用凸显了基础水文地球化学特征在自然过程与人为影响双重背景下的重要性。