In pipeline infrastructure EPC (Engineering, Procurement and Construction) projects especially irrigation, deciding the optimized pipeline distribution network alignment is very critical in governing the cost of the project. This process of network routing involves tedious manual efforts and requires huge skilled engineering man-hours to route a pipeline network that needs to comply several constraints like slope, settlements, stagnant waterbodies, inaccessible locations, forests and crossings across prominent roads, railways & streams. While many researches have been carried out to route single linear pipeline, no researches/studies have attempted to route a distribution pipeline network. To overcome the setbacks, an optimized and automated pipeline distribution network routing embedding the concept of hydrology and least cost path method (Dijkstra's algorithm) in GIS environment has been developed. Dijkstra’s algorithm is widely used for routing problems to provide the shorted cost path from the origin/ source to the destination(s) over a given surface (Ex: terrain). Introduction of hydrology aspect with the Dijkstra’s algorithm is the key here. A case study of typical irrigation pipeline network design has been carried out to validate the proposed routing model in-comparison with the conventional routing and the outcome of the study are as follows: 1) the automated pipeline network route had the least length compared to the conventional procedure, 2) the number of crossings across the prominent roads, railways and streams has drastically reduced, 3) the time taken to provide a network routing by the model was almost a day whereas conventional procedure took a couple of weeks, 4) detailed hydraulic study showed that, the total cost of pipeline for the routing provided by the model is much lesser than the conventional route.