|摘要: || 地下水開發成本低，水質較不易受污染，且地下水的出水量穩定，對乾旱時期的供水具有非常大的價值。地下水流動慢、補注不易，若長期超限利用將會導致地下水源逐漸枯竭，造成地層下陷與海水入侵的嚴重災害，因此，倘能掌握地下水變動的情勢，將有助於地表水與地下水資源管理與調配運用。|
Groundwater is low cost, good water quality and sustained yield that is valuable for water supply during drought periods. Groundwater flow is slow and difficult to recharge, if long-term over-extraction will cause groundwater depletion gradually, land subsidence and salt-water intrusion. Therefore, analysis and assessment of trends in groundwater level can provide useful information for conjunctive management of surface water and groundwater.
In this study, Zhuoshui River is divided into two sub-areas, the alluvial fan area and mountainous area, to investigate interaction mechanism between surface water and groundwater during typhoon periods. The study uses principal component analysis, correlation analysis and water balance method to explore the effect of the amount of rain on groundwater level variation and recharge.
The results show that: (1) In the first, second and third aquifers, the time lag of groundwater recharge from rainfall were about 2, 6 and 30 hours, respectively. The accumulated amount of rain area reached 400mm and 200mm in the mountainous area and at Siluo rain gauge that can effectively recharge groundwater in the entire alluvial fan of Zhuoshi River.(2) From the principal component analysis, the first principal component scores of the first aquifer started rising when the accumulated amount of rain at Siluo rain gauge reached 20mm; those of the third aquifer started rising when the accumulated amount of rain in the mountainous area was over 200mm. (3) From correlation analysis, the water levels of groundwater observation wells of the same layer in the first and second aquifers water has highly linear correlation, regardless of the amount of rainfall. However, the correlation between the water levels of Haiyoun and Haifeng observation wells in third aquifer become higher when the accumulated amount of rain is higher. (4) From the water balance analysis, the greater accumulated amount of groundwater, the longer the second aquifer level rise lasting. When accumulated amount of groundwater are low, groundwater flow rate is slow that makes the third aquifer level cannot rise within four days.