Conservation and efficient management of water resources are crucial for the sustainability of irrigated agriculture. One approach to conserve water for agriculture is to use field water management technologies or conservation agriculture. The objective of this study was to evaluate different water management methods on water productivity by providing a great attention to crop coefficient estimation. For this, four treatment groups were compared within their irrigation application methods: 1.Wetting Front Detector (WFD) and Time Domain Reflectometer (TDR) with in overhead application for onion yield and 2. Conservation agriculture (CA) and conventional tillage (CT) within drip application for garlic yield. To achieve the comparison, the experimental plots were prepared and grouped in to four categories. For onion the comparison result showed that both treatment groups i.e., WFD and TDR were found to be good for irrigation water management. The WFD seemed an appropriate simple water management method with non-significant difference, but 7% lower irrigation depth than those applied in the TDR based on the soil water balance method. This non significant reduction of irrigation depth in WFD resulted in a non significant 22% higher yield and 26 % higher water productivity of onion compared to TDR. For garlic the comparison result showed that CA treatment was significantly difference from CT with 28% lower applied irrigation depth. This significant reduction of irrigation depth in CA resulted in a significant 12% higher yield and 29% higher water productivity of garlic compared to CT. The average seasonal crop coefficient value of onions was estimated in each growing stage and the values for WFD and TDR were 0.57 and 0.65 for initial stage, 0.71 and 0.76 for development stage, 0.99 and 1.09 for mid stage and finally 0.8 and 0.84 for harvest stage respectively. For garlic the values of CA and CT were 0.57 and 0.65 for initial stage, 0.67 and 0.82 for development stage, 0.82 and 1.07 for mid stage and finally 0.71 and 0.82 for harvest stage respectively. There for, this study showed that WFD and CA with drip are more advantages for conservation of water and maximize crop yield