地下水觀測水位線性集塊系統模式建立與應用

Development and Application of A Liner Lumped System Model for Groundwater Head Observations

張乃蓉(Nai-Jung Chang)

指導教授 ： 徐年盛

國立臺灣大學/工學院/土木工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803100

摘要

本研究的目的在於建立一合乎地下水知識背景之地下水集塊系統模式與各觀測井的地下水位線作擬合。使用地下水位觀測資料結合訊號分析評估地下水區的抽水源，再利用降雨觀測資料與河川水位觀測資料評估地下水區的補注源，經由參數率定找出與真實地下水位觀測值擬合最相近之模式參數，這些參數即可看出各觀測井區域的地下水行為並且可以作為評估抽水源、補注源之依據，亦可推估研究區域之水文地質參數，並將模式應用於補遺地下水位。本模式假設地下水為一封閉系統，考慮其出流量與入流量對地下水位變化的影響，此系統模式假設各地下水觀測井為一地下水庫，以五大地下水影響因素：觀測井與觀測井間地下水流通量、河川影響、降雨入滲、人為抽水及其他流失與補注所構成，並且考慮研究區域多井的綜合效應與整體區域的地下水平衡，使模式更加完善且具物理意義。本研究將所建立的地下水集塊系統模式應用於台中盆地烏溪以北之區域，以12 口水利署自記井作為本研究之欲模擬觀測井，其模擬年限為2012 年8 月1 日至2017 年5 月31 日，以小時為時間單位進行模擬。率定結果發現，大部分測站之地下水位模擬誤差RMSE 皆在50 公分以下，模式之參數在空間上的分佈亦具有合理性，可反映現地之真實情況，而在此研究區域，模式求得之透水係數與比出水率數值與抽水試驗相近，其結果可作為水文地質參數的估算；本研究更結合了主成份分析，以統計的角度驗證地下水集塊系統模式確實有抓取到此研究區域影響地下水位之因素，而在本研究之研究區域，第一個主要影響因素為地形，整個研究區域除了萬豐地區以外地勢皆是北高南低，造成地下水流由北向南流，兩兩地下水井的水流交換佔了重要的比例，其二影響為降雨補注，最後是人為抽水行為；最後本模式經由補遺方法驗證，驗證模式的補遺效果在資料缺漏15%資料長的情況下依然能維持一定的品質。

關鍵字

地下水庫模式 ； 抽補強度 ； 參數率定 ； 地下水補遺 ； 主成份分析

並列摘要

The aim of this study is to establish a liner lumped system model for groundwater head observations. Use groundwater level observations combined with signal analysis to estimate pumping sources, and use precipitation data, river elevation data for recharging sources. The best parameters of lumped system model will be found by optimal process, which can be utilized to observe groundwater behavior of study area. Furthermore, we apply this model for supplementing groundwater data.Assuming the groundwater system is a closed system, and considers the effect of outflow and inflow. The model is composed of five factors: the relationship of two observation wells, the impact of river, recharge of precipitation, pumping and other effects. In addition, we consider the complex effect of multiple wells and the water balance of groundwater system in the study area.This study applied the model in Taichung basin. The simulated period is from August 1, 2012 to August 2017 in units of hours. The result shows that the RMSE between simulations and observations of the groundwater level are less than 50 cm. The spatial distributions of the parameters of the model are also reasonable, and those parameters can reflect the real situation of the study area. The values of permeability coefficient and storage coefficient that model calibrated are similar to the pumping test, so the established model of this study area can be used to estimate hydrogeological parameters. This study combines Principal components analysis and verifies a lumped system model that did capture the factors affecting the groundwater level from a statistical point of view in this study area. The first major impact factor is topography causing the exchange of water flow between the two wells accounts for an important proportion. The second impact is recharge of precipitation, and final impact is pumping. Finally, this model is validated that can still maintain a certain quality when the data is missing 15% of the data.

並列關鍵字

Groundwater reservoir model ； Pumpimg recovering strength ； Parameters calibration ； Groundwater data supplementing ； Principal Components Analysis

參考文獻

1. Arnold, J. G., Muttiah, R. S., Srinivasan, R., and Allen, P. M. (2000). Regional estimation of base flow and groundwater recharge in the Upper Mississippi river basin. Journal of Hydrology, 227(1-4), 21-40.

2. Bear, J., Hydraulics of Groundwater, New York, McGraw Hill International Book CO.,1979

3. Dong, D. L., Wu, Q., Zhang, R., Song, Y. X., Chen, S. K., Li, P., Liu, S. Q., Bi, C. C., Lu, Z. Q., and Huang, S. L. (2007). Environmental Characteristics of Groundwater: an Application of PCA to Water Chemistry Analysis in Yulin. Journal of China University of Mining and Technology, 17(1), 73-77.

4. Fenicia, F., Savenije, H. H. G., Matgen, P., & Pfister, L. (2006). Is the groundwater reservoir linear? Learning from data in hydrological modelling. Hydrology and Earth System Sciences Discussions, 10(1), 139-150.

5. Fleury, P., Plagnes, V., & Bakalowicz, M. (2007). Modelling of the functioning of karst aquifers with a reservoir model: Application to Fontaine de Vaucluse (South of France). Journal of Hydrology, 345(1-2), 38-49.