The primary source for these waterbodies is groundwater from both inside and outside the immediate surface drainage area. The groundwater is often mineral rich, resulting in above neutral pH and alkalinity greater than 50 ppm. Spring ponds are usually less than 10 acres, and have no inlet, but may have an outlet, occasionally joining with spring runs to feed into larger spring lakes. Spring lakes are often greater than 10 acres, have no inlet, but typically do have an outlet, often forming the headwaters of streams particularly in northern Wisconsin. Due to their smaller size, spring ponds are cooler than spring lakes. The submerged community of both spring ponds and spring lakes is often dominated by muskgrasses (Chara spp.), which thrive in alkaline water. Coon-tail (Ceratophyllum demersum), naiads (Najas spp.), common waterweed (Elodea canadensis), and wild celery (Vallisneria americana) are also common. The non-native invasive watercress (Nasturtium officinalis) is often found growing in shallower areas and may completely cover the water's surface. These lake types are often surrounded by white cedar dominated northern wet-mesic forests. Fish species associated with spring ponds include brook trout, creek chub, common shiner, white sucker, and mottled sculpin.
