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.

泉水作为地下水系统的天然排泄通道，参与水文循环，并为周边社区提供稳定可靠的饮用水源。本研究针对尼泊尔中部丘陵地区塞蒂科拉流域（Seti Khola Watershed）内168处季节性动态变化的常年泉开展物理化学特征评估，研究区域涵盖不同地质背景（以碳酸盐岩和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）。研究聚焦于现场物理化学参数实测，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。本研究以泉水属性的野外实测数据与遥感数据（含Landsat-8 OLI卫星影像）为基础，探究了地表状况与泉水水温之间的关联。研究结果显示：雨季充沛的降水会稀释溶质，提升溶解氧含量；而旱季更高的蒸发速率则会使溶质浓度升高。本研究发现，非碳酸盐岩区域的pH值波动显著，且与较低的氧化还原电位值呈相关关系；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。海拔越高，泉水水温越低，且土地覆被类型的差异会影响泉水的热状况。季节性动态变化凸显了水文地球化学基本特征在自然过程与人为影响背景下的重要性。