未飽和層水力參數之空間變異性對溶質傳輸行為之研究

Effect of Spatial Variability of Hydraulic Parameters on Solute Transport in the Unsaturated Zone

李振誥(Cheng-Haw Lee) ； 潘建邦(Jian-Bang Pan) ； 林碧山(Bih-Shan Lin)

《鑛冶：中國鑛冶工程學會會刊》 39卷4期 (1995/12) Pp. 91-104+55

https://doi.org/10.30069/MM.199512_39(4).0010

摘要

本文主要以序率模式來探討水力參數之空間變異性對大區域未飽和層地下水溶質傳輸行為所造成之影響，並與定率模式做一比較。本文首先探討地表地下水補注量、飽和透水係數、飽和含水量，以及地表至地下水面深度四種水力參數之空間變異性對未飽和層溶質傳輸所產生之影響。接著以監測系統中駐留濃度和通量平均濃度二種監測模式來探討在定率和序率模式下，地表地下水補注量、飽和透水係數、土壤延散度及地表至地下水面深度四種水力參數之空間變異性在二種濃度監測模式所造成的影響。結果顯示，若將各水力參數視為獨立變數，以「地表至地下水深度」之空間變異性對未飽和層溶質傳輸有最大的影響，「地表地下水補注量」之空間變異性的影響次之，再依次為「飽和透水係數」、「飽和含水量」及「土壤延散度」。未飽和層地下水流速愈低時，水力參數之空間變異性愈顯重要，同時，水力參數空間變異性愈大，定率和序率模式間之差異也愈大。

關鍵字

序率模式 ； 未飽和層 ； 溶質傳輸 ； 空間變異

並列摘要

The effect of spatial variability in hydraulic parameters is investigated for field scale solute transport in the unsaturated zone. In this paper, the variability in the recharge applied on the surface, the depth from the surface to the groundwater table, the hydraulic conductivity at saturation and some other hydraulic parameters, is considered. Since natural fields exhibit a large variability in their hydraulic properties, accurate field scale modelling of flow and solute transport must account for the heterogeneity. In order to achieve the objective, adopting a simple stochastic model is adequate. Stochastic model is used in the article, and compared with the deterministic model. The results indicate that solute penetration into the groundwater through the unsaturated zone is significantly affected by the spatial variability in the hydraulic parameters. The spatial variability in the depth from surface to the groundwater table, appear to have the most significant effect on solute transport through the unsaturated zone. Then the spatial variabilities having significant effects are the recharge applied on the surface, the hydraulic conductivity at saturation, the water content at saturation and the dispersivity of the soil in sequence. When the velocity of the groundwater flow is lower, consideration of the spatial variability in hydraulic parameters is more important. The results also show as the larger the spatial variability in hydraulic parameters is, the larger the difference between deterministic and stochastic model.

並列關鍵字

Stochastic model ； Unsaturated Zone ； Solute Transport ； Spatial Variability