[4] With the increase of European settlers, the Winnebago were subject to forced relocation by the United States government several times.

Once they were removed from the Green Lake area, they were moved to Iowa until the establishment of a reservation in Blue Earth County, Minnesota.

Many large, wooden hotels and one short-lived casino populated the north shore during the late 19th century in Green Lake, Wisconsin.

[3] The City of Green Lake, with a population of 828 as of 2018,[8] is located on the northeast shore at the outflow of the Puchyan River.

The valley finally flooded when a recessional moraine about 90 m (300 ft) high blocked the exit of water at the west end of the basin during the Cary stage of glacial reduction.

The shoreline is diverse, ranging from sandy beaches to swamps to steep cliffs where the bedrock is exposed, such as in the image on the left.

The land is covered in drumlins, parallel troughs and ridges with rolling tops that rise to a height of 30–60 m (98–197 ft).

These ridges are covered in a thin layer of glacial till that is composed mainly of sand eroded from the native sandstones in the area.

[14] The water level increase caused by the dam at the head of the Puchyan has had profound impacts on the shoreline of the lake, mainly in the creation of many immature beaches.

The maturity of these beaches is dictated by the composition of the shore, where looser till material erodes much more quickly than even the fragile sections of exposed bedrock.

This has implications for lake health because with very low rates of flushing, there is a large lag for reversion of fertility changes.

Based on other chemical characteristics such as pH and chlorophyll fluorescence at this depth, it is likely that the metalinetic oxygen minimum results from a concentration of respiring plankton.

A paleolimnological sediment analysis conducted in the deep basins of the lake showed trends of oxygen depletion since 1950.

[15][12] Phosphorus is also a key element in living things, constituting molecules such nucleic acids and phospholipid membranes.

[13] Current lake management efforts focus heavily on monitoring and reducing phosphorus loading within the drainage basin by controlling erosion, runoff, and fertilizer use.

Angling also puts heavy pressure on the population, so size and bag limits have been implemented to help reduce the strain.

Recent surveys in Green Lake have shown that the cisco population has slightly declined, possibly due to the ecological effects of eutrophication.

There have been reports of scarring on adult lake trout, suggesting possible conflict with muskellunge in the boundaries between the warm and cold-water fisheries.

A main threat facing the fish of the cold-water fishery is oxygen depletion, especially in the deep west basin.

The Wisconsin record cisco was caught on Big Green Lake on June 12, 1969, by Joe Miller and weighed 4 lb 10.5 oz (2.11 kg).

Coontail is a common aquatic species in Wisconsin and able to survive and thrive in areas with light deficiency as it receives a majority of nutrients from the water.

The ability to grow in deeper areas of the littoral zone allows coontail to provide habitat for invertebrates and fish.

[13] Prior to European settlement, the lake was considered to be oligotrophic, meaning that it had low biological productivity and good water quality based on a trophic state index.

A 2014 survey showed that hybrid water milfoil increased in dominance to make up 25% of the aquatic plant species.

The most frequently found singular plant species in the lake in 2015 was Eurasian water milfoil at 20% of relative frequency.

[19] Common carp have contributed to the degradation of plant species and fish spawning locations in the shallow areas of the lake in addition to the Silver Creek inflow and nearby County K Marsh.

Placing carp barriers have contributed to a regeneration of the aquatic plant species in the Silver Creek inflow, but not for the County K Marsh.

The unsuccessful control in County K Marsh is attributed to the high levels of phosphorus that enter from Silver Creek.

The organization works by acquiring environmentally sensitive properties, such as woods or wetlands, and protecting them by placing them into conservancy.

The marina in Dartford Bay offers access to town by boat and leads into Deacon Mills Park.