A lake near Interlaken, Switzerland serves many purposes
Here is a happy picture of a happy lake surrounded by happy mountains at Interlaken, Switzerland. The U-shaped valley (looks like a smile, right?) between the mountains is a dead giveaway that tremendous glaciers once existed here and carved out the valley leading to the lake. This picture also shows how lakes serve many purposes. From the beginning of human times, people lived near water bodies for water supply and also to get rid of wastes. I'm sure the people living here in Interlaken would tell you that the lake adds to the aesthetic pleasure of life....as well as to the property values of those residents who live near the water.
Springs Discharging Groundwater in the Grand Canyon
This photo shows groundwater discharging from springs in the Redwall Limestone wall of the Grand Canyon at Vasey's Paradise, Arizona, USA into the Colorado River. The limestone composition of the underground rock and the layering and fracturing of the aquifers in this area allow for water to move relatively quickly downgradient (horizontally and downhill), and when an opening to the land surface (in this case, a vertical wall) is found, groundwater discharge can occur in significant amounts.
Snowmelt: Glacier melting in springtime causes high streamflows
Mountain snow fields, and glaciers, to a lesser extent, act as natural reservoirs for water in some areas, such as the western United States and Canada. These semi-permanent ice fields store precipitation from the cool season, when most precipitation falls and forms snowpacks, until the warm season when snowpacks melt and release water into rivers.
As much as 75 percent of water supplies in some western states are derived from snowmelt. As this picture of Bow River Falls, downstream from the Bow Glacier in Banff, Canada shows, spring meltwater can provide for some dramatic viewing for visiting tourists. Glacier-melt runoff often has this distinctive greenish color, often due to the suspension of very fine minerals in the water.
As this picture of Stephens Glacier in Alaska shows, glaciers are just frozen rivers of ice flowing downhill. Glaciers begin life as snowflakes. When the snowfall in an area far exceeds the melting that occurs during summer, glaciers start to form. The weight of the accumulated snow compresses the fallen snow into ice. These "rivers" of ice are tremendously heavy, and if they are on land that has a downhill slope the whole ice patch starts to slowly grind its way downhill. These glaciers can vary greatly in size, from a football-field sized patch to a river a hundred miles (161 kilometers) long.
This picture shows the Grinnell Glacier in Glacier National Park, Montana, USA in 2005. The glacier has been retreating rapidly since the early 1900's. The year markers point to the former extent of the glacier in 1850, 1937,1968, and 1981. Mountain glaciers are excellent monitors of climate change; the worldwide shrinkage of mountain glaciers is thought to be caused by a combination of a temperature increase since the Little Ice Age, which ended in the latter half of the 19th century, and increased greenhouse-gas emissions.
This photo shows Silver Glen Springs in the Ocala National Forest, Florida. Florida has large numbers of springs due to the abundance of karst geology and porous limestone below the land surface. The spring pool at Silver Glen Springs is about 200 feet across. While it's only about 2 to 3 feet deep in many places, around the outflow hole the depth is about 18 feet. Typical of springs, the water is very clear and free of suspended and particulate matter, unlike water flowing in rivers and in lakes.
Wide-spread flooding in Lithia Springs, Georgia, just west of downtown Atlanta, after an epic rainfall event on 22 Sept. 2009. Impervious surfaces and urban buildup causes rainfall to runoff much quicker than in natural settings, and with greater flooding consequences, during heavy rains.
As this picture shows, in many urban/suburban areas there are extensive impervious areas, such as parking lots, streets, houses, and buildings that, instead of allowing rainfall to soak into the ground, as in natural conditions, cause direct runoff of rainfall during storms. Impervious surfaces can have an effect on local streams, both in water quality and streamflow and flooding characteristics.
A significant portion of rainfall in forested watersheds is absorbed into soils (infiltration), is stored as groundwater, and is then slowly discharged to streams through seeps and springs. Flooding is less significant in these conditions because some of the runoff during a storm is absorbed into the ground, thus lessening the amount of runoff flowing into a stream during storms. As watersheds are urbanized, much of the vegetation is replaced by impervious surfaces, thus reducing the area where infiltration to groundwater can occur. These areas quickly carry stormwater runoff directly to streams, increasing the likelihood of more frequent and more severe flooding.
Tidal Marshland in the Plum Island Estuary, Massachusetts
The marshes of Plum Island Estuary are among those predicted by scientists to submerge during the next century under conservative projections of sea-level rise. Many coastal wetlands worldwide-including several on the U.S. Atlantic coast—may be more sensitive than previously thought to climate change and sea-level rise projections for the 21st century.
Several coastal marshes along the east coast of the United States, for example, have limited sediment supplies and are likely to disappear this century. Vulnerable east coast marshes include the Plum Island Estuary (the largest estuary in New England) and coastal wetlands in North Carolina's Albemarle-Pamlico Sound (the second-largest estuary in the United States).
In this photo, sediment-laden water from a tributary is entering a much clearer Lake Tuscaloosa in Alabama, USA. Many lakes in the southeastern United States are really reservoirs, or rivers with a dam, which causes the river water to back up and form a lake.
I don't know the exact circumstances of the sediment-heavy inflow into the main body of Lake Tuscaloosa here, but this could be a case of a large rainstorm occuring somewhere in the watershed, possibly in a distant location from the lake. If a storm occurred over a landscape that was able to contribute dirt into a tributary, then the sediment-laden tributary flow would eventually flow into Lake Tuscaloosa. It is very common to see parts of lakes that have heavy suspended sediment and turbidities and much clearer water literally yards away.
An alpine lake: Hidden Lake, Glacier National Park, Montana
When choosing a picture of a lake for this Web site, I naturally chose the type of lake (there are many) that I like best—a high mountain lake in an alpine setting. This picture shows Hidden Lake in Glacier National Park, Montana, USA. Being far away from any urban setting, the water in this lake is probably very pure and certainly very cold. In lower elevations, many lakes get their water both directly from precipitation and runoff from the surrounding landscape, along with water entering from streams.
High in the mountains, it is doubtful there is much input from large streams to fill up this lake. This lake is kept full of water mainly from precipitation runoff from the surrounding hills and, in the spring, from snowmelt (this picture was taken in the "warm" month of August; the view in April must be much different).
This picture shows students from Idaho enjoying the unique experience of "floating high" in the Dead Sea in the Middle East. Notice how they seem to be sitting up as if in a chair...and the chair is the highly-saline water, in this case. The Dead Sea is extremely saline, due to the fact that the water body does not have an outflow point, so the salt that washes in from the surrounding watershed concentrates over time. And salt water is more dense than fresh water (and here, more dense than seawater), thus allowing these students to learn something about density and water.
This picture is an aerial view from above Mono Lake in California, towards the west-southwest; Paoha Island in center of lake. The white rings are salt deposits left onshore as the water level declines to serve the water needs of Los Angeles. The declining water level of the lake is clearly seen by the parallel lines and white-colored lake deposits ringing the shore. The diversion of fresh-water inflow to the city of Los Angeles and evaporation has led to the decline in water level at a rate of about 1 meter per year. The snow-covered mountains in the background are the Sierra Nevada.
Urban lakes, like Greenlake Lake in Seattle, Washington, are highly valued by local residents. Where urban lakes exist, you'll find lots of walkers and joggers, people enjoying canoeing and swimming, picnickers, and, of course, lots of dogs and ducks. The water can sometimes be used for water supply for a city's needs, also. Urban lakes do have special needs, though. Water quality must be monitored constantly; it would not be good for the mayor of a town to become ill from swimming in polluted water. The inflow of nutrients, such as phosphorus and nitrogen from fertilizers, must be restricted in order to prevent the overgrowth of algae. And, where there is wildlife, such as ducks, around, there is the chance of bacteria problems.