地下水抽補量與參數時空分布率定之方法建立與數值實驗驗證

Development of Methodology and Validation Using Numerical Experiment for Calibrating Temporal-spatial Distribution of Groundwater Pumpage, Recharge and Parameters

徐年盛(Nien-Sheng Hsu) ； 黃建霖(Chien-Lin Huang) ； 劉宏仁(Hung-Jen Liu) ； 李冠緯(Guan-Wei Li)

《農業工程學報》 61卷3期 (2015/09) Pp. 1-28

https://doi.org/10.29974/JTAE.201509_61(3).0001

摘要

本研究應用經驗正交函數法建立一套地下水抽補量與參數時空分布率定方法，並配合數值實驗以驗證應用於實務之成效；本研究方法主要分為六大部分：（1）設定研究區域近似於實際之抽補量與參數時空分布、邊界條件與起始條件；（2）應用地下水數值模式模擬地下水頭之時空分布以視為實際之觀測資料；（3）利用觀測之地下水位計算蓄水量歷線與蓄水變化量以反推多類型式下抽補量之時間分布；（4）應用經驗正交函數法配合觀測之地下水位反推抽補量之空間分布；（5）計算抽補量之時空分布並應用數值模式模擬地下水位；（6）敏感度分析以評估抽補量推估誤差對於參數率定與地下水位模擬之影響；（7）反推淨補注量之時空分布；（8）應用經驗正交函數法配合地下水位模擬誤差歷線進行淨補注量時空分布與參數空間分布率定。本研究將所建立之方法應用於屏東平原地下水系統，結果顯示，應用經驗正交函數法所反推之抽補量時空分布，其權重平均準確率可達到95.24%，地下水位數值模擬權重平均準確度則達到96.89%；敏感度分析結果顯示，每增進1%之地下水位模擬準確度約將造成水力傳導係數誤差增加1.24%；經過率定後，淨補注量與水力傳導係數之準確率可分別提升至97.14%與95.11%，因此證實本研究所建立之方法可有效且準確地率定抽補量與參數之時空分布。

關鍵字

經驗正交函數 ； 地下水抽補量時空分布率定 ； 地下水參數率定 ； 數值實驗驗證 ； 地下水歷線分析法

並列摘要

This study applies empirical orthogonal function (EOF) to establish a methodology for calibrating temporal-spatial distribution of groundwater pumpage, recharge and parameters, and applies numerical experiment to validate the applicable effect. The methodology of this study can be divided to six parts: (1) set up approximately actual temporal-spatial distribution of pumpage, recharge and parameters, boundary conditions and initial conditions; (2) simulate temporal-spatial distribution of groundwater level using numerical model and regard that as actual observed data; (3) compute groundwater storage hydrograph and variation in storage according to observed groundwater level for inverse evaluating the temporal distribution of pumpage and recharge under multiple practices; (4) apply EOF with observed groundwater level for inverse evaluating the spatial distribution of pumpage and recharge; (5) compute the temporal-spatial distribution of pumpage and recharge and simulate groundwater level using numerical model; (6) sensitivity analysis for assessing the effect of evaluated error of pumpage and recharge toward parameters calibration and simulated groundwater level; (7) inversely evaluate the temporal-spatial distribution of recharge; and (8) apply EOF with simulated error hydrograph of groundwater level for calibrating recharge and hydraulic conductivity. This study applies the established method on the groundwater system of Pintung plain. Results show that, the weighted average precise percentage of inverse evaluated temporal-spatial distribution of pumpage and recharge using EOF reaches 95.24%; and for numerical simulated groundwater level, 96.89%. Furthermore, the results of sensitivity analysis of spatial parameters calibration using EOF show that while increasing 1% of simulated accuracy of groundwater level, the hydraulic conductivity would decrease 1.24% of accuracy. The calibrated precise percentage of recharge and hydraulic conductivity can respectively reach up to 97.14% and 90.35%. Hence, the established method of this study can effectively and accurately calibrate temporal-spatial distribution of groundwater pumpage, recharge and parameters after validation and proof using numerical experiment.

並列關鍵字

Empirical orthogonal function ； Temporal-spatial calibration of groundwater pumpage and recharge ； Groundwater parameter calibration ； Numerical experimental validation ； Groundwater hydrograph analysis