There are a number of factors that need to be considered. One is the intensity of rain events. Our rain events may be less frequent but are more intense. This means a more intense flushing of the catchment basin into the lake and a potentially greater nutrient loading. And there's more development everywhere, not just the lakeshores, to contribute nutrient to the lake through its tributaries. Shoreline development does lead to fewer trees at the shoreline and less shade. More sunlight penetration allows more photosynthesis and warms water temperatures which further stimulates growth. Increased wave action erodes shoreline soils and stirs up bottom sediments introducing more nutrients within the water column. Individuals that somehow "forget" their aquatherm is still set to run daily and has been "accidentally" turned down towards the lakebed or who irresponsibly chose to use devices designed to blow sediments away from lakebed areas contribute even more nutrient s to the water column. As I have explained before algae growth works like any other form of combustion. it's all about fuel to air ratio. Lease the nutrients settled on the lakebed with a limited surface exposed to dissolve O2 and there will be some algae growth on and near the bed. Mix those nutrients up into the column with greater exposure to dissolve O2 and growth growths explodes.
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