A reliable water accounting framework is crucial for understanding the contribution of water resources in meeting agricultural demands and selecting appropriate operating systems for off-farm water systems, including hydraulic conveyance and distribution structures. This ensures fair, adequate, and dependable irrigation water distribution, especially under water scarcity operational scenarios. This study presents a novel and effective method for modifying PSU tables in the SEEA water accounting framework that is specifically designed for small-scale agricultural water management study areas. The proposed approach entails a comprehensive analysis of the surface water distribution within the water holders using a hydraulic simulation model and a spatial analysis of the groundwater extraction for meeting on-farm water demands. This approach was implemented on Iran's Central Plateau and revealed notable variations in water rights and distribution effectiveness among stakeholders so that, surface water contributed 27–40% less than the legal water rights, leading to aquifer overexploitation. The evaluation indicated that changing crop patterns and upgrading to pressurized irrigation systems led to 4–7.5% overexploitation of groundwater and 3.5–6% water conservation on farm scales. Besides, the spatial assessment verified a considerable overlap of 59% between the farms with modern irrigation systems and those with cultivated area expansion, resulting in sustained overexploitation pressure on the aquifer. The present study has two significant practical implications. Firstly, it specifies the contribution of surface- and groundwater resources in fulfilling the water demands of individual water-holders. Secondly, it provides reliable information to decision-makers about the incentives for modernization, rehabilitation, and renovation projects in an irrigation district.

可靠的水核算框架对于了解水资源在满足农业需求方面的贡献以及为非农用水系统（包括水力输送和分配结构）选择适当的操作系统至关重要。这确保了公平、充足和可靠的灌溉用水分配，特别是在缺水的情况下。本研究提出了一种新颖有效的方法来修改 SEEA 水核算框架中的 PSU 表，该框架专为小规模农业水管理研究领域而设计。所提出的方法需要使用水力模拟模型对水库内的地表水分布进行全面分析，并对地下水抽取进行空间分析，以满足农场用水需求。该方法在伊朗中部高原实施，揭示了利益相关者之间水权和分配有效性的显着差异，导致地表水贡献比法定水权少 27-40%，导致含水层过度开采。评估表明，改变作物模式和升级加压灌溉系统导致地下水过度开采 4-7.5%，农场规模的节水率降低 3.5-6%。此外，空间评估证实，拥有现代灌溉系统的农场与扩大耕地面积的农场之间存在59%的相当大的重叠，导致含水层持续遭受过度开采压力。本研究有两个重要的实际意义。首先，它明确了地表水资源和地下水资源在满足个体水户用水需求方面的贡献。其次，它为决策者提供了有关灌区现代化、恢复和改造项目激励措施的可靠信息。