有效利用水资源的有效规划需要复杂的计算机辅助规划工具。水资源市政和工业需求研究所（IWR-MAIN）系统就是这样一个工具。IWR-MAIN是一个季节性和部门性分解模型，可以为住宅、非住宅和公共/其他用水部门编制需水量预测。此外，通过使用保护有效性和效益成本模块，可以评估保护计划实施的节水及其相关成本。此外，可以通过评估长期和短期需求侧和供应侧备选方案来完成干旱规划。IWR-MAIN 5.1版目前正在进行一些设计改进。新设计中采用的模块化方法将产生更高效、模块化和可扩展的产品，更容易接受系统修改。 住宅和非住宅子部门的重新分类将提供更清晰的信息，并在执行数据收集和输入时提高易用性。住宅和非住宅部门使用的知识库整合了近20年数据收集和分析的结果。对于典型用户来说，守恒分析更明确、更容易（以稍微增加的数据需求为代价）。额外的后处理单元可用于检查保护实施的经济效益；进行干旱分析；聚合和比较多个文件运行；将数据导出到其他系统；报告编写和查看；以及数据和结果的图形显示。

Effective planning for efficient use of water resources calls for sophisticated computer-aided planning tools. The Institute for Water Resources Municipal and Industrial Needs (IWR-MAIN) System is one such tool. IWR-MAIN is a seasonally and sectorally disaggregate model that can prepare water demand forecasts for residential, nonresidential, and public/other water use sectors. Additionally, water savings from conservation program implementation and their associated costs can be assessed through employing the conservation effectiveness and benefit- cost modules. Furthermore, drought planning can be accomplished through the evaluation of long-term and short-term demand-side and supply-side alternatives. IWR-MAIN Version 5.1 is currently undergoing a number of improvements in design. The modular approach employed in the new design will result in a more efficient, modular, and extensible product that more readily accepts system modification. Reclassification of the residential and nonresidential subsectors will provide more clarity and will enhance ease of use when performing data gathering and entry. The knowledge base employed in the residential and nonresidential sectors integrates the results of nearly 20 years of data gathering and analysis. Conservation analysis is more explicit and much easier for the typical user (at the expense of slightly increased data requirements). Additional postprocessing units are available for examining the economic benefits of conservation implementation; performing drought analysis; aggregating and comparing multiple file runs; exporting data to other systems; report writing and viewing; and graphic display of data and results.