本文给出了一个水库效率图，以帮助接触时间（CT）水库设计师，并描述了该设计工具在估算所需水库长宽比和进出口水力要求以实现目标接触时间方面的优势。该图已成功用于阿拉斯加、加拿大和48个以下项目的多个CT储层设计。该设计工具首次用于开发乌纳拉斯卡市氯接触蓄水池的挡板和入口/出口管道设计。Unalaska的冷未过滤水源需要大量的消毒接触时间，以满足美国环境保护署地表水处理规则的最低3对数灭活信用要求。介绍了挡板系统和多端口入口/出口管道等设计要素，并报告了1994年示踪试验研究的结果。

This paper presents a Reservoir Efficiency Graph to assist contact time (CT) reservoir designers and describes the benefits of this design tool to estimate the required reservoir length-to-width ratio and the inlet/outlet hydraulic requirements to achieve a target contact time. This graph has been used successfully for several CT reservoir designs for Alaskan, Canadian, and Lower 48 projects. This design tool was first used to develop the baffle and inlet/outlet piping design for the City of Unalaska's chlorine contact reservoir. Unalaska's cold, unfiltered water source requires significant disinfection contact time to meet the minimum 3-log inactivation credit requirement of the US Environmental Protection Agency's Surface Water Treatment Rule. Design elements such as the baffle system and multi-port inlet/outlet piping are presented, and the results of a 1994 tracer test study are reported.