濁水溪流域內集水區地下水流動性與交換量評估

Evaluation of Inter-catchment Groundwater Flow in Choshui River Basin

陳信宇(Hsin-Yu Chen) ； 葉信富(Hsin-Fu Yeh)

《農業工程學報》 69卷1期 (2023/03) Pp. 41-54

https://doi.org/10.29974/JTAE.202303_69(1).0004

摘要

水文模式通常假設集水區之間地下水流在邊界沒有交換，稱為封閉式模式，然而這種假設經常不符合實際狀況。因此，本研究選擇濁水溪流域五個相鄰的集水區作為研究區域，利用2011年至2020年水平衡資料計算有效集水區指數，判斷集水區是否有地下水進出的情況，同時以開放式降雨－逕流模型探討地下水交換量。結果顯示，內茅埔集水區從外部接收地下水，龍門橋集水區則向外輸出地下水。研究結果發現開放式模式表現大多優於封閉系統模式表現，內茅埔集水區在乾季時期，封閉模式有低估流量的現象，在開放模式即能準確地預測流量。全年尺度下，內茅埔集水區年均地下水交換量為472 mm，佔年均降雨22%；龍門橋集水區年均地下水交換量為340 mm，佔年均降雨11%。其中，乾季時期內茅埔集水區與龍門橋集水區地下水交換量佔同時期降雨的比例高達55%與19%，本研究結果顯示地下水交換量在整體水文循環中為重要的組成，評估地下水交換量能提升水平衡估計水資源與其應用上的準確性。

關鍵字

地下水流 ； 水平衡 ； 降雨－逕流模式 ； 濁水溪流域

並列摘要

The hydrological model, often known as the closed model, typically assumes that there is no groundwater exchange at the boundaries between catchments. Yet, this assumption is rarely satisfied. Therefore, this study selected five adjacent catchments in Choshui River Basin and calculated the effective catchment index to determine whether there is groundwater exchange using water balance data from 2011 to 2020. In this study, an open rainfall-runoff model was used to quantify groundwater exchange. Nei Mao Pu catchment receives groundwater, while the Long Men Bridge catchment exports groundwater. The performance of the open rainfall-runoff model was superior to that of the closed model. During the dry season, streamflow in the Nei Mao Pu catchment was overestimated by the closed model while being accurately predicted by the open model. Annual average groundwater exchange in the Nei Mao Pu catchment is 472 mm, accounting for 22% of the annual average rainfall. Annual average groundwater exchange in the Long Men Bridge catchment is 340 mm, accounting for 11% of the annual average rainfall. In the dry season, the proportion of groundwater exchange to the rainfall was 55% and 19% in Nei Mao Pu and Long Men Bridge catchment, respectively. This study suggests that groundwater exchange is an important component of the hydrological cycle. The evaluation of groundwater exchange may increase the precision of water balance estimation and related applications.

並列關鍵字

Groundwater flow ； Water balance ； Rainfall-runoff model ； Choshui river basin

參考文獻

Alvarez-Campos, O., Olson, E. J., Welp, L. R., Frisbee, M. D., Zuñiga Medina, S. A., Díaz Rodríguez, J., Roque Quispe, W. R., Salazar Mamani, C. I., Arenas Carrión, M. R. and Jara, J. M. “Evidence for High-elevation Salar Recharge and Interbasin Groundwater Flow in the Western Cordillera of the Peruvian Andes”. Hydrology and Earth System Sciences, Vol. 26, No. 2, pp. 483-503, 2022.

Ameli, A., Gabrielli, C., Morgenstern, U. and McDonnell, J. “Groundwater subsidy from headwaters to their parent water watershed: A Combined Field‐modeling Approach”. Water Resources Research, Vol. 54, No. 7, pp. 5110-5125, 2018.

Arsenault, R., Brissette, F. and Martel, J.-L. “The Hazards of Split-sample Validation in Hydrological Model Calibration”. Journal of Hydrology, Vol. 566, No., pp. 346-362, 2018.

Ball, L. B., Caine, J. S. and Ge, S. “Controls on Groundwater flow in a Semiarid Folded and Faulted Intermountain Basin”. Water Resources Research, Vol. 50, No. 8, pp. 6788-6809, 2014.

Bouaziz, L., Weerts, A., Schellekens, J., Sprokkereef, E., Stam, J., Savenije, H. and Hrachowitz, M. “Redressing the Balance: Quantifying Net Intercatchment Groundwater Flows”. Hydrology and Earth System Sciences, Vol. 22, No. 12, pp. 6415-6434, 2018.