The Lakes of the Four Seasons, a community in Lake and Porter Counties in northwestern Indiana, contains highly eutrophic lakes. A diagnostic feasibility study of the lakes was initiated in December 1981, and continued through November 1982. Morphometric, limnological and hydrologic characteristics of the lakes were defined in order to permit the development of nutrient and hydrologic budgets for the lakes. In addition to the development of these budgets, preliminary testing of a lake restoration technique, phosphorus precipitation, was performed. These studies and the resultant budgets provided necessary information for the formulation of feasible restoration methods for the lakes. The recommended restoration methods, if implemented, could enhance and maintain water quality conducive to recreational use and aesthetic enjoyment.The Lakes of the Four Seasons system has a mass water loading of 3.596 x 106 m3 Y-1and a hydraulic residence time of 0.71 y. Mass external phosphorus loading to the lakes is 537.34 kg –1 . Mass nitrogen loading to the system is 13,457 kg y -l.Big Bass Lake has a mass water loading of 2.316 x 106 m3 y-1 and a hydraulic residence time of 0.16 y. Mass external phosphorus loading to the lake is 356.76 kg y -l. Mass nitrogen loading to Big Bass Lake is 12,260 kg y -l.Lake Holiday/Lake on the Green has a mass water loading of 3.423 x 106 m3 y 1 and a hydraulic residence time of 0.65 y. Mass external phosphorus loading to the lakes is 330.52 kg y-1. Mass nitrogen loading to the Lake Holiday/Lake on the Green is 11,980 kg y1.Both loading and in-lake nitrogen:phosphorus ratios indicated phosphorus limitation in these lakes. The eutrophic condition of the lakes was also indicated by in-lake nutrient concentrations as well as excessive algal and macrophyte growth. Rapid 02 depletion, which occurs in water overlying the sediments even though the lakes are fairly well mixed, also testifies to the extreme productivity of the lakes.Restoration options for these lakes include short term cosmetic methods, longer term options for the disruption of internal phosphorus cycling, and abatement of phosphorus loading from the watershed. The cosmetic options involve the use of herbicides and algicides to give immediate relief from excessive primary productivity. Dredging and drawdown/sediment consolidation are aired at reducing internal phosphorus loading, while methods directed at the abatement of phosphorus loading from the watershed attack the cause of the lake system's problems. The longer term options necessitate further studies before implementation.