Lysimetric and eddy covariance techniques are commonly used to directly estimate actual crop evapotranspiration ($E{T}_a$). However, these technologies are costly, laborious, and require skills which make in situ ET estimation difficult, particularly in developing countries. With this in mind, an attempt was made to determine $E{T}_a$ and stagewise crop coefficient (K_c) values of transplanted puddled rice using a modified non-weighing paddy lysimeter. The results were compared to indirect methods, viz., FAO Penman–Monteith and pan evaporation. Daily $E{T}_a$ ranged from 1.9 to 8.2 mmday⁻¹, with a mean of 4.02 ± 1.35 mmday⁻¹, and their comparison showed that the FAO Penman–Monteith equation performed well for the coefficient of determination (R² of 0.63), root mean squared error (RMSE = 0.80), and mean absolute percentage error (MAPE = 13.6 %), and was highly correlated with $E{T}_a$ throughout the crop season. However, the pan evaporation approach was underestimated (R² of 0.24; RMSE = 0.98; MAPE = 22.13%) due to a consistent pan coefficient value (0.71), vegetation role and measurement errors. In addition, actual K_c values were obtained as 1.13 ± 0.13, 1.27 ± 0.2, 1.23 ± 0.16, and 0.93 ± 0.18 for the initial, crop development, mid-season, and end-season stages, respectively. These estimated crop coefficient values were higher than FAO K_c values. Statistical analysis results revealed that the overall stagewise-derived average K_c values were in line with FAO values, but different from the derived pan K_c values, although found insignificant at a 5% significance level. In addition, water productivity and agro-meteorological indices were derived to evaluate the cultivar performance in this experiment. Therefore, such a methodology may be used in the absence of weighing lysimeter-derived K_c values. The derived regional K_c values can be applied to improve irrigation scheduling under similar agro-climatic conditions.

The irrigation water-pricing (IWP) system may prove to be an effective tool for meeting the increased demand for water. It includes the totality of costs that water users incur for irrigation purposes, based on principle, i.e., fixed, volumetric and crop-based. Factors like crop type, area irrigated, number of irrigations and total volume of water used by water users are considered for initiating the decision-making process of IWP in many countries of the world. There is no uniform set of principles for fixing water rates; a multiplicity of factors are followed, such as the capacity of irrigators to pay, recovery of water cost, crop water requirement, sources of water supply and its assurance. Linear programming, the Full-cost and Bayesian Network model, Residual value method, Principal Agent model and spot market pricing model have been used to estimate the impact of an IWP policy on water users. In the Indian context, a rationalized IWP mechanism alone will not suffice if the revenue collection mechanism is not streamlined and strengthened throughout the country. In order to develop a full-fledged volumetric IWP system in India, considerable changes need to be made in irrigation water supply infrastructure and operational plans need to be developed, which will provide a good balance between efficiency and equity objectives.

The irregularity in monsoon has severely affected the water availability at surface and sub-surface systems. Diminishing surface and sub-surface availability has not only decreased the water availability, but it additionally affected the ecosystem and increased disastrous situations like floods and droughts, resulting problems of stress on groundwater recharge. Groundwater recharge is a technique by which infiltrated water passes through the unsaturated region of groundwater and joins the water table. It is based upon soil type, land use land cover, geomorphology, geophysical and climate (viz. rainfall, temperature, humidity etc.) characteristics of a region. Over the years, due to variations in weather pattern and overexploitation of aquifers groundwater recharge has decreased and groundwater level has reduced in the most parts of the country. This has led to severe water deficit problems in several parts of the country. This can be solved by different direct and indirect methods of groundwater recharge technology. This technology can reduce the wastage of water and enhance groundwater availability for uses in different sector like irrigation, domestic and industrial uses.

Water is synonyms of life. World are facing acute water scarcity owing to growing freshwater demand, climate linked rainfall aberrations and miserable management of water resources. Selection of suitable site for water harvesting structure is crucial for water management in any basin. In the present study soil and water assessment tool (SWAT) and analytical hierarchical process (AHP) technique was applied for decision making at Hydrological Response Unit level. Keeping in mind the groundwater recharge, AHP technique was used for delineation of water harvesting sites using soil type, slope, runoff ratio and land use land cover criteria. In this study, SWAT model performed satisfactory during calibration and validation. Model coefficient of determination (R²) ranged from 0.85 to 0.92, Nash Sutcliffe Efficiency (NSE) ranged from 0.85 to 0.92, standard deviation ratio (RSR) ranged from 0.28 to 0.38, and percent bias (PBIAS) ranged from −14.68 to 0.79 for calibration while R² ranged from 0.68 to 0.80, NSE ranged from 0.70 to 0.81, RSR ranged from 0.30 to 0.40 and PBIAS ranged from −12.7 to 0.57 for validation. Result of AHP revealed that upper region of basin has highest potential of water harvesting/groundwater recharge, which can be mange efficiently by specific water harvesting structure such as contour bunding, graded bunding, conservation bench terrace, contour trenches conservation ditches and broad bed and furrow. In case of middle and lower region, farm pond, check dam, tanks and reservoirs are recommended. The tools and techniques used in study can be adopted in identical environmental and physical conditions to arid and semi-arid agro-climatic regions worldwide, for efficient water resource planning at HRU level.

In order to address current global water shortages, geovisualization tools such as remote sensing and geographic information systems aid planners and decision makers in generating more effective and correct judgments for the execution of water harvesting activities for the maximum utilization of rainwater. Keeping in view, a weighted sum approach technique was used to infer hydrological behavior and priorities at watershed level in the Harohar sub-basin of middle Gangetic plains. It was observed that monsoon rainfall (1.7 mm year⁻¹) and post-monsoon rainfall (0.6 mm year⁻¹) has been declined whereas pre-monsoon rainfall (1.5 mm year⁻¹) has significantly increased over the period 1985–2019. Furthermore, morphometric, slope, hydrological, geomorphological, and lithological variations results revealed that 56.30% of areas are prioritized as very high, followed by high (30.5%), and only 2–7% of areas fall under very low to low priority for construction of rain water harvesting structures. Water harvesting facilities such as farm ponds, check dams, tanks, aharpynes, and conservation ditches might be offered in prioritized locations for optimum utilization of surface runoff and ground water recharge. Based on the above scientific findings, this study may be helpful in water resource planning at the basin/watershed level across the globe

HIGHLIGHTS. The residual value approach was applied to estimate water economic values in the canal- and tube well-irrigated areas.Water value for vegetable crop