Agricultural water resources face increasing pressure due to climate variability, rising food demand, and limited water availability. Efficient and adaptive management strategies are essential to maintain agricultural productivity while preserving environmental sustainability. This chapter introduces an AI agent system to support agricultural water resources management by integrating environmental monitoring, hydrological simulation, crop water demand modeling, and policy evaluation. The system utilizes multiple specialized agents, each responsible for a specific task, and is coordinated by a Large Language Model (LLM) interface that interacts with users, interprets queries, and delegates actions to appropriate agents. This modular and intelligent system offers a powerful decision support tool for farmers, policymakers, and researchers aiming to achieve sustainable water use in agriculture.