Resource managers must balance the impacts of competing management decisions on multiple, interacting natural systems. Hydrologic and ecological processes, such as groundwater fluctuations and riparian evapotranspiration, can be tightly coupled. Ideally, managers would have tools and models that include all processes to better understand how each management action would propagate through the environment. Because resources are limited, management tools that include only the most important processes may be more realistic. However, in some cases, omitting some interactions can lead to significant errors in predictions of hydrologic outcomes and ecological function, severely limiting a manager’s ability to identify...