||本研究之目的為推衍基本水文資料且建立數學模式，以冀精確求算流域內之可供水量，並應用系統模式，合理地推求一區域之最佳用水方式。 本研究內容以建立水筒模式及系統分析模式為重點，其要點如下： (1)水筒模式：係考慮流域內複雜之水文現象，諸如入滲、滲漏、貯留、蒸發、地表逕流、中間流、基流等現象，以水筒濾層之概念模式予以模型化，模擬流域內河川之逕流量，以推估流域內河川可供水量。 (2)系統分析模式：係考慮地下水補助量、有效雨量、河川可供水量及其用水型態，以推求區域內最佳用水方式。 本研究中之水筒模式以烏溪流域大肚橋水文站河川逕流量為模式驗證之憑據，並以流量與孔口上方高度成線性及非線性兩種關係加以研究。系統分析模式則以烏溪流域北投新圳灌溉配水規劃方式為根據，以缺水模式分別針對定面積法、定流量法及設計頻率為1.11年及1.25年之河川引水量，以研究其最佳配水方式。 經模擬結果，顯示本研究中之各模式具有相當合理及實用價值，可供流域水資源調配規劃釐定之參考。 The purpose of this study is to establish suitable mathematical models in an attempt to calculate with accuracy the expectant water supply within a river basin. Furthermore, it also aims reasonably to derive the best way to estimate available water for utilizing in a certain agricultural area. This study lays stress on setting up Tank Model and Systems-Analysis Model. (1) Tank Model: By applying of tank-filtering conceptual model, simulating the runoff discharges of the rivers within a project area so as to estimate its expectant water supply in consideration of the complicated hydrological phenomena of river basin. (2) Systems-Analysis Model: To examine and investigate the best way of water utilization by applying operations research techniques in consideration of the subsidiary supply from ground water, effective rainfall, the expectant natural water supply of rivers. Thus, optimum available water of the project area can be estimated. The Tank Model is constructed in accordance with the river runoff of Tatu Bridge hydrologic station, Wu Chi Basin, as the basis of the verification of model. Meanwhile, further quest has been paid to the linear and nonlinear relationship resulting from the discharge and orifice height. A Systems-Analysis Model is made according to the scheme of the irrigation and water distribution of Pei-tou Canal, Wu Chi Basin, by taking into consideration the water-deficit concept. The model is focusing on constant-area method and constant-discharge method and will 1.11-year and 1.25-year design frequencies respectively, to estimate river diversion supply and then derive the best scheme for water allocation. The results of the simulation reveal that models adopted in this study are of considerably rational and applicable value. The approach will provide supreme reference for scheming the planning and utilization of water resources.