From 2014 to 2016, water agencies in Southern California provided more than $350 million in rebates to owners who converted their turf to drought‐tolerant landscaping. In order to provide a fuller understanding of the water savings of this program, this study establishes that there was a behavioral contagion, or a multiplier effect, from rebate participants in the program. An imagery‐based, time‐series analysis of 20 Southern California neighborhoods from 2012 to 2018 was performed to detect what parcels converted their lawns without a rebate and how they were spatially correlated with rebate participants. This correlation was then used on almost 55,000 rebate participants to estimate the multiplier benefits for the entire program at 132%. For every 100 rebate participants, the multiplier effect helped contribute to an additional 132 parcels to convert to drought‐tolerant landscaping. This methodology was compared with a previous study in the Irvine Ranch Water District providing similar results. This study provides the Metropolitan Water District of Southern California a better understanding of the water savings per rebate dollar of the Turf Removal Rebate Program as well as providing a robust approach for cities or water agencies to estimate the multiplier effect of their turf rebate programs.

中文翻译：

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使用时间序列航拍图像量化南加州草皮清除返还计划的乘数效应

从2014年到2016年，南加州的水务机构向将草皮转变为耐旱美化环境的业主提供了超过3.5亿美元的回扣。为了更全面地了解该计划的节水情况，本研究确定了该计划的回扣参与者存在行为传染性或乘数效应。对2012年至2018年南加州20个社区进行了基于图像的时间序列分析，以检测哪些地块在没有折扣的情况下转换了草坪，以及它们与折扣参与者之间的空间关系。然后，将这种相关性用于近55,000名回扣参与者，以估计整个计划的乘数收益为132％。每100名回扣参与者，乘数效应帮助增加了132个宗地，以转化为耐旱的美化环境。将该方法与尔湾牧场水区的先前研究进行了比较，得出了相似的结果。这项研究使南加州大都会水区更好地了解了草皮清除计划的每笔返水节水，并为城市或水务机构提供了一种可靠的方法来估算其草皮折扣计划的乘数效应。