Springs

Photo of Alley Spring's pool of blue water.

Springs are openings in the ground or rock where underground streams or seeps release water into caves or on the ground. Missouri has many great examples of springs.

Springs, along with caves, sinkholes, and natural bridges, are all features of karst regions. Much of Missouri is a karst landscape of porous limestone and dolomite with deep fissures.

Springs Are Part Of The Karst Cycle

Slightly acidic groundwater flows through cracks in limestone or dolomite, slowly dissolving the rock. The cracks widen to form cavities and eventually a subterranean drainage system.

When a cave is below the water table, it is filled entirely with water. (Well-drillers search for these water-filled pockets.) When the cave is above the water table, the cave has air in it and its water flows ever downward. Wherever underground water exits the rock and flows into the open air, it is called a spring. Spring water can discharge from the ground due to gravity or hydrostatic pressure (the pressure exerted by standing water).

Some of our largest caves formed ages ago as completely water-filled cavities. Over geologic time, the Ozark Plateau was uplifted, and rivers carved valleys ever deeper into the bedrock, creating bluffs and causing cave passages to be above the water table and to drain.

All the land through which water moves into groundwater or into springs or caves is called a recharge area. For a single cave system, this area can be many miles wide. Pollutants, such as agricultural chemicals and animal waste, roadway runoff, leaking septic tanks, contaminants from trash thrown into sinkholes, and even excess silt from a variety of construction and agricultural earthworks, can seep into the groundwater, polluting caves, springs, and well water.

Human Connections

In the days before refrigerators were available, springs and caves, which are always about 55F, were prized locations for cold storage of food and beverages.

Few people are aware of it today, but between 1800 and 1930, our mineral springs, and at least 80 resorts and spas that developed around them, drew hundreds of thousands of visitors to Missouri seeking “healing waters.” Our earliest settlers, notably Nathan Boone, boiled the water from natural salt springs to yield the salt necessary for frontier survival.

Spring Subtypes

There are many ways of categorizing springs, but it’s helpful to think of the following divisions.

Seeps

Some springs are the merest trickle, and they produce wetland communities called seeps. Here, soils are saturated with groundwater that wells up through layers of mucky soil. Because the water discharge is so diffused and flows so slowly, you might not even recognize it as a kind of spring.

Seep communities are roughly divided, by their water chemistry, into acid seeps, calcareous seeps (including fens), and saline seeps.

Underground Streams

What we usually think of as “springs” are underground streams, which are usually associated with aquatic caves. Some produce just a trickle of water, but the largest can churn out hundreds of millions of gallons each day. As with seeps, the water produced by an underground stream can be fresh or mineralized or salty.

In the Ozarks, springs often appear as a crevice or opening in a rock wall, where water flows out. Much of the clarity and coolness of Ozark streams comes from spring water that feeds into them.

Missouri’s large, cool, aqua-blue springs are a source of wonder — and tourism revenue — for our state. Some of our most beautiful rivers and float streams are spring fed.

  • The water that pools around a spring often appears blue because of the depth of the water and the way the minerals in the water reflect the light shining on it.
  • Spring water is cold (about 56F) because that is the constant temperature of the ground deep beneath the surface.
  • Although spring water might seem safe to drink, it is not: Any pollution entering the ground for perhaps miles around the spring may be in the water, along with viruses, bacteria, and other microbes that can cause illness. You should treat it as you would any other creek water.

While seeps can be regarded as terrestrial wetland communities, flowing springs are viewed as aquatic habitats similar to creeks and streams, with plants that grow underwater, partially out of water, or on the banks. Where springs flow into streams and rivers, their cool, clear, well-oxygenated water creates a special habitat inhabited by a unique community of plants and animals: certain ferns, watercress, gilled aquatic snails, isopods, crayfish, salamanders, sculpins, and more. Trout, which are coldwater fish, can be successfully stocked in some spring-fed Ozark streams because of the springs’ cooling influence on the water.

Because many springs are associated with caves, many aquatic cave-dwelling animals appear where the caves open into springs, especially after heavy rains or floods.

Nearly 4,000 springs have been officially mapped in Missouri (so far). The majority are in the southern half of Missouri, mostly in the Ozark Highlands ecoregion, where they occur in soluble dolomite or limestone.

The largest and most spectacular springs are on public land as Missouri State Parks or Conservation Areas. Many smaller springs occur on private land, too, and are not open to the public.

Photo of fall color at Alley Spring
Alley Spring, in Shannon County, provides a stunning contrast between its turquoise water and fall color.
Eileen Eck
Photo by Eileen Eck, courtesy Missouri Department of Conservation
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Photo of fall color at Alley Spring
Building on Karst: Best Practices
Photo of a pink planarian on a rock.
Turbellarians (Planarians; Free-Living Flatworms)
Dugesia, Planaria, and other genera
Unlike their parasitic cousins in the flatworm group, turbellarians, or planarians, are tiny carnivores or detritus-eaters that glide smoothly across submerged leaves and other objects.
Photo of several prosobranch pond snails crawling on a rock.
Gilled Aquatic Snails (Prosobranch Pond Snails)
Over 20 Missouri species in former subclass Prosobranchia
Gilled snails are one of two main groups of aquatic snails in Missouri (the other group is the "lunged" snails). Gilled snails, or prosobranchs, breathe with gills and possess a hard trapdoor-like operculum. They are most common in the Ozarks.
Photo of amphipod on a rock
Scuds and Sideswimmers (Amphipods)
Species in the crustacean order Amphipoda
Often overlooked by people, but eagerly sought by fish, Missouri’s amphipods resemble shrimplike sowbugs. Scuds live in various aquatic habitats, and several species inhabit caves.
Photo of an aquatic isopod in an aquarium, crawling on a rock.
Aquatic Pillbugs and Sowbugs (Aquatic Isopods)
Freshwater members of the crustacean order Isopoda
Everyone knows about terrestrial sowbugs and pillbugs, but many isopod species are aquatic. Missouri has several isopods that live in streams, ponds, rivers, and caves.
Photo of a spothanded crayfish viewed from above on white background.
Crayfishes
About 38 species in Missouri
Crayfish are freshwater aquatic invertebrates that look a lot like small lobsters, to which they are related. There are about 38 species of crayfish in Missouri.
Grotto sculpin side view photo with black background
Grotto Sculpin
Cottus specus
The grotto sculpin is a rare fish adapted cave conditions. It has recently been designated an endangered species under the Federal Endangered Species Act. It's found only in Perry County, Missouri.
Ozark cavefish side view photo with black background
Ozark Cavefish
Amblyopsis rosae
The Ozark cavefish is small, colorless, and blind. It lives only in springs, cave streams, and underground waters. It has been declared Endangered in our state and as Threatened by the U.S. Fish and Wildlife Service.
Southern cavefish side view photo with black background
Southern Cavefish
Typhlichthys subterraneus
The southern cavefish has a long, flattened head without eyes. It is whitish-pink because it lacks pigmentation. The only other Missouri fish that lacks eyes is the Ozark cavefish.
Image of a cave salamander
Cave Salamander
Eurycea lucifuga
The cave salamander is a common amphibian of the Ozark Plateau. It lives in caves, springs, and rocky streams. Recognize it by its normally bright orange skin dotted with dark brown or black spots.
Image of a grotto salamander
Grotto Salamander
Eurycea spelaea
The grotto salamander is Missouri’s only species of blind salamander. A true troglobite, it lives in total darkness and has small eyes that are completely or partially covered by their pink or beige skin. Occurs in wet caves in the Ozarks.
A reddish-brown salamander with an orange stripe down its back is curled on a moss-covered rock.
Ozark Zigzag Salamander
Plethodon angusticlavius
The Ozark zigzag salamander is small and slender, with a narrow, somewhat lobed back stripe that can be yellow, orange, or red. This woodland species lives in Missouri’s southwestern counties along the Arkansas border.
Photo of a southern red-backed salamander on an oak leaf.
Southern Red-Backed Salamander
Plethodon serratus
The southern red-backed salamander is small and slender, with a distinct, narrow, red or orange stripe along the back that has saw-toothed edges. It hides under rocks, mosses, and rotten logs in Ozark forests.
Photo of a western slimy salamander
Western Slimy Salamander
Plethodon albagula
The western slimy salamander is a black to blue-black salamander irregularly marked with silvery flecks. It occurs in the Ozark Highlands and the Lincoln Hills north of the Missouri River. True to its name, it secretes a thick substance that sticks to skin like glue.
Image of a pickerel frog
Pickerel Frog
Lithobates palustris (formerly Rana palustris)
The pickerel frog is medium-sized, with square or rectangular spots in two parallel rows down the back. There is a distinct ridge of skin along each side of the back. It is absent from the northwestern third of Missouri.
Image of a wood frog
Wood Frog
Lithobates sylvaticus (formerly Rana sylvatica)
The wood frog is tan, pinkish tan, or brown, with a dark brown mask through the eye and ear. It is perfectly camouflaged among fallen dead leaves. A rare frog, it lives in cool, wooded hillsides in portions of eastern Missouri and some southwestern counties.
Photo of a beaver half in water
American Beaver
Castor canadensis
The American beaver is a semiaquatic rodent distinguished by its large size, webbed hind feet, and large, horizontally flattened tail covered with leathery scales.
photo of river otter
North American River Otter
Lontra canadensis
The North American river otter was once nearly eliminated in Missouri, but thanks to restoration efforts, these powerful swimmers are once again found throughout most of the state.
Photo of path rush, closeup showing drying fruits.
Rushes
Juncus spp. and Luzula spp.
Missouri has 24 species in the rush family. Distinguishing between these grasslike plants can be tricky, but it’s easy to learn some basics about the group.
Photo of eastern woodland sedge plant growing among leaf litter.
Sedges
Carex, Schoenoplectus, Scirpus, and other genera
Missouri has more than 200 species in the sedge family. Distinguishing between these grasslike plants can be difficult, but it’s easy to learn some basics about the group.
Photo of watercress flowers
Watercress
Nasturtium officinale (syn. Rorippa nasturtium-aquaticum)
Spring branches and streams in the Ozarks are decorated with large colonies of these plants, which can grow like thick green garlands in the water. It has a long history of use as a salad green, and it is cultivated to sell to gourmet cooks. If you collect watercress from the wild, make sure to wash it thoroughly.
Photo of spotted touch-me-not or jewelweed flower.
Spotted Touch-Me-Not (Jewelweed)
Impatiens capensis
Many Missouri children learn about this orange-flowered native plant by playing with the juicy green seedpods, which, when ripe, "explode" upon the slightest touch. This is jewelweed's mechanism for seed dispersal, and it's the reason for the name "touch-me-not."

Aquatic Caves

Cave Spring
Aquatic Caves

Caves with creeks, groundwater, or springs are known as aquatic or wet caves. Many rare and vulnerable animals call these dark, wet tunnels home.

Caves and Karst

Photo of interior of Jacob's Cave showing a variety of speleothems.
Caves and Karst

With more than 7,000 caves, Missouri is known as "the Cave State." This is because much of Missouri is a karst landscape of porous limestone and dolomite, where caves, springs, sinkholes, and natural bridges form. These features support unique communities of animals, including threatened and endangered species.

Sinkholes and Sinkhole Ponds

Sinkhole
Sinkholes and Sinkhole Ponds

Sinkholes, just like the caves beneath them, are common in regions with karst geology. When sinkholes are blocked and form ponds, they support unique wetland communities.

Ozark Streams

Photo of the creek flowing away from Alley Spring
Ozark Streams

The Ozark Aquatic Faunal Region lies mostly south of the Missouri River. Its streams are typically clear, cool, and fast-flowing, with high gradients and chert bottoms.

Rivers and Streams

Mississippi River
Rivers and Streams

Our rivers and streams are a source of pride for Missourians. We rely on them for our quality of life, and we must care for them.

Wetlands

Little Bean Marsh natural area
Wetlands

Wetlands are a transition zone between land and aquatic environments, and they protect the quality of both. A rich variety of plants and animals live in wetlands.