Carpenter et al., linked loads, exports, and concentrations of phosphorus (P) in the Yahara Chain (a group of four lakes) in Wisconsin, USA, to some load reduction plans. The authors expected that improving water quality should be in balance with management across the chain. The parameters used in this research were: 29-33 years of data for P inputs and outputs, initial concentrations for each lake, and zooplankton (Daphnia Pulicaria) activity for the two upper lakes only (Lake Mendota and Lake Monona). The study site included four lakes in the Yahara Chain: Mendota, Monona, Waubesa, and Kegonsa. Lake Mendota is the largest and deepest of the 4 lakes, it has a tributary derived from agricultural and urban sources. The tributary of Lake Monona is urban and is the second largest and deepest lake. For Lake Waubesa, which is the smallest and shallowest lake, tributaries come from urban and agricultural areas. And the last lake, Kegonsa Lake, has an agricultural tributary and is really shallow. For modeling the pattern was in the same order, Lake Mendota first, Lake Monona next in the chain, Lake Waubesa third, and Lake Kegonsa at the end of the chain. For the model, the authors built an empirical model based on P loads, summer concentrations, and downstream exports. Once they had the model, they used it to determine probability distributions for P concentrations. This empirical model was based on a data-driven approach. Information on drainage loads, exports, and P concentrations was obtained from the North Temperate Lakes Long-term Ecological Research (NTL-LTER) program, US Geological Survey, and Wisconsin DNR, creating time series information. For loads at the La…… middle of the paper…… the P transport of each lake depended (based on the developed model) on the lake immediately upstream and in the additional drainage and on the P that are on the sediments (the latter parameter is more important for the shallower lakes Lake Waubesa and Lake Kegonsa). For this study the annual ratio obtained, based on the upstream lake, was for Lake Monona 0.56, for Lake Waubesa 0.79 and for Lake Kegonsa 0.72. With this research, the authors wanted to study the variability of the system of four lakes in the Yahara chain and determine the responses to the five different established load reduction plans, obtaining a model that can be used to project the response of the lake to the different plans, although the authors underline the variability of the system and the need to take into account the complex biogeochemical process that occur in this type of systems.