Storm Solute Changes in the Fushan Forested Watershed, NE Taiwan

臺灣北部福山森林集水區之暴雨溶質變化

10.29417/JCSWC.199606_27(2).0002

王立志(Lih-Jih Wang)；金恆鑣(Hen-Biau King)；夏禹九(Yue-Joe Hsia)；黃正良(Jee-Lian Hwong)；劉瓊霦(Chon-Bin Liou)；林登秋(Teng-Chiu Lin)

Water Chemistry ； Storm Solute Changes ； Fushan Watershed ； 水化學 ； 暴雨溶質變化 ； 福山森林集水區

中華水土保持學報

27卷2期（1996 / 06 / 01）

97 - 105

英文

Hydrological monitoring and water collecting system was set up to study the storm solute changes in the subtropical Fushan Forest. Results showed that 2 types of rainfall patterns, eg., Summer thunderstorms and winter frontal storms, occured in 1993 in this watershed. Streamflow responded quickly to summer thunderstorm events. The time lags between peak rainfall and peak flow were generally about 35 minutes during summer thunderstorms, but were more than 10 hours during winter frontal storms. Changes of solute concentration during summer thunderstorms were stronger than those during winter frontal storms indicating relatively larger portions of near-surface water contributed to stormflow during summer thunderstorms. Conductivity, pH, Na^+, Ca^(2+), Mg^(2+), CI^-, SO_4^(2-) and HCO_3^- in streamflow exhibited decreases in concentrations with increasing flow rate both during summer and winter storms, but decreases were lower during winter frontal storms. Suspended solids, K^+, NH_4^+, NO_3^- and total P showed increases with increasing flow rate, but little or no increases during winter frontal storms. These solute behaviors suggested that storm water chemistry was controlled by the relative mixing of near-surface flows and deep flows during storm events in this watershed.

本研究於臺灣北部福山試驗集水區設置水文監測及溪水收集系統，以了解暴雨期間溪水溶質的變化。結果顯示1993年間的暴雨以夏季午候雷陣雨及冬季鋒面雨兩種型式發生。溪水水位通常迅速反應夏季雷陣雨的降水，溪流洪峰的發生於降水尖峰35分鐘之內。但冬季時，溪流洪峰則於冬季鋒面型降水尖峰之後發生。而夏季暴雨期間，溪水中溶質濃度的變化則較冬季鋒面降雨期間之變化明顯，顯示夏季暴雨期間，其大部份溪流洪鋒來自接近地表的水流。當水位變化時，溪流水中的電導度、酸鹼值，以及Na^+、Ca^(2+)、Mg^(2+)、Cl^-、SO_4^(2-)及HCO_3^-等離子濃度皆隨水位升高而降低，而其降低程度以冬季鋒面雨期間較不明顯。至於水中的懸浮固體、K^+、NH_4^+、NO_3^-及全磷的濃度則隨水流增加而增加，其增加程度亦以冬季鋒面雨期間較不明顯。此些溶質的表現顯示暴雨期間的溪流水化學主要由接近地表的水流與土壤深層水流相對混合所控制。