ABSTRACTLand Irrigation Area in Pakan Sinayan Kenagarian Kamang Mudia Kecamatan Kamang Magek Agam District with an area of ± 20.40 ha is rain-fed rice field which irrigation water rely on rain water only. To overcome this, Sumatra River Basin V has built a groundwater water drill well located in Jorong Pakan Sinayan. The drill well is still using a diesel generator set generator sets as a generator.This study aims to determine the cost of capital and annual costs, economic feasibility and payback period of investment capital. Based on the calculation, the amount of cost incurred for the development of ground water irrigation using Generator Set Machine is Rp 2,886,443,895.00 and the annual operational & maintenance cost is Rp 138,617,475.00. The cost of agricultural management per year is Rp.453.430.800,00.Total revenues from paddy fields per year obtained by farmers is Rp. 983.178.000,00. From the calculation results obtained value BCR = 1.05, NPV = RP. 473,914,568.00, IRR = 7.03%, and Break Event Point is obtained in the 8th year. So it can be concluded that the development project of Longstorage Kali Mati is economically feasible. the amount of cost incurred for the development of Irrigation of Ground Water using Solar Power Generation is Rp 3,118,363,047,00 and operational & maintenance cost per year equal to Rp 46.850.600,00. From result of calculation got value of BCR = 1,249, NPV = RP. 2.291.028.516, IRR = 10.36%, and Break Event Point is obtained in year 7. So it can be concluded that the Irigais Development project is groundwater economically feasible if using one of the two generators, but the payback time is faster if using solar power plant.