自來水工程建設，必須具有長遠之計畫，且因建設經費龐大，自來水事業單位須就管網計畫供水量，先規劃配水幹管、配水池等，若僅於管網中設置管線時，則須以最大時供水量為設計基準；若增設能調節供水量之配水池時，必須同時考慮於每日不同供水時段管線及配水池之容量關係。 管網工程規劃十分複雜，一般須由專家或經驗豐富人員依據統計資料或計劃所訂之供水量，先假設管網內各管線之流量、管徑等，再利用流量、能量等守恆原理，計算出假設之差值，反覆調整流量、管徑、水壓，直到在容許誤差範圍內，再進一步編列細部設計與計算所需費用。在本研究中，則利用數學規劃方法，以最小建造費用為目標函數，將須應用之水力原理及自來水工程規範，分別建構為兩個不同的數學模式，以應用於選用管線之規格管徑及設置配水池地點之最佳化方案決策。 本研究之案例為重力式配水管網，水流能以適當的壓力及流速到達管網的任一部份，以滿足用水戶最大用水時段之需求，並探討管徑、水壓、及流速等因素對最小建造費用之影響，以提供決策者或設計者對配置管線及設置配水池與否之參考。 Water supply construction should build a long-term plan，as the construction demand a enormous cost so that Water Supply Department should plan the water distribution pipeline together with water distribution tanks etc. in advance for fulfilling the network planned water supply rate. If only pipeline erection is being processed in the network, then the design of maximum hourly should be base on water supply rate; if water distribution tank is additionally erected for adjusting the water supply rate, we should simultaneously consider the relationship of the pipeline and water distribution tanks of different water supplying durations of everyday. Since the network planning is very complicated, generally, the flow rate and pipe diameter etc of each pipeline within the network should be first assumed in accordance with the statistical data or planned water supply rate by the expert or highly experienced personnel, then by applying the conservation principle of the flow rate and capacity etc to calculate the differed value of the assumption. Repeatedly adjusting flow rate, pipe diameter, water pressure, until up to within the allowable error. Then, process further budgeting the cost necessary for detailed designing and calculation. In this research, mathematical planning method is applied by taking the smallest construction expense as the target function. The applying hydraulic theory and water supply work specifications should separately be built as two different mathematic modes for applying to the standard pipe diameter of the selected pipeline and the arranged water distribution tank location as the optimization scheme policy. The example of this research is gravity distribution network. Water current can reach any part of the network with proper pressure and flow speed for fulfilling the demand of the water utilizing customers within the maximum water utilization period. And to probe the reasons such as pipe diameter, water pressure and flow speed that may affect the smallest construction expense for providing reference to the decision makers or designer in determining whether or not pipeline arrangement and water distribution tank are required.
