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How Do They Drain Lakes? Unveiling the Mysteries of Lake Drainage

How Do They Drain Lakes? Unveiling the Mysteries of Lake Drainage

Have you ever wondered how they drain lakes? And where does the water go when they do?

I have too. So, I decided to find out and share what I learned with you.

Turns out, there are a few different ways to drain a lake. And where the water goes depends on how the lake is drained.

So, if you’ve ever wondered about this, read on to learn more!

What are lakes?

A lake is a naturally occurring large body of water in a basin surrounded by dry land. The water in a lake is much slower-moving than any inflow or outflow streams that serve to feed or drain it. Most lakes are freshwater, but some are salt lakes with salinities even higher than seawater.

Creeks and rivers typically drain lakes, but some are endorheic without any outflow, while some volcanic lakes are filled directly by precipitation runoffs and do not have any inflow streams. Rivers or creeks also feed many lakes. Some are artificially controlled, such as reservoirs usually constructed for industrial or agricultural use, hydroelectric power generation, supplying domestic drinking water, ecological or recreational purposes, or other human activities.

To drain a lake, the first step is to identify the source of the water that is feeding the lake. Once the source is located, the water can be diverted from the lake by either redirecting the water or creating a channel or pipe system to control the flow. The next step is to build a dam or other control structure to prevent the water from flowing back into the lake. The final step is to manage the flow of water so that it is diverted away from the lake and into a different water body.

lovatnet lake Beautiful Nature Norway.

What are the different types of lakes?

There are 11 major types of lakes, each of which has been classified and named according to various factors such as thermal stratification, oxygen saturation, salinity, seasonal variations in lake volume and water level, degree of outflow, etc.

The 11 major types of lakes are:

  1. Tectonic lakes – Formed by geologic activity such as faulting and folding.
  2. Volcanic lakes – Formed by the eruption of volcanoes.
  3. Glacial lakes – Formed by the melting of glaciers.
  4. Fluvial lakes – Formed by running water, such as plunge pools, fluviatile dams, and meander lakes.
  5. Solution lakes – Formed by dissolving soluble materials such as limestone and gypsum.
  6. Landslide lakes – Formed by the collapse of land caused by landslides or earthquakes.
  7. Aeolian lakes – Formed by wind-blown deposits such as sand, silt, and clay.
  8. Shoreline lakes – Formed by the deposition of sediments along the shoreline of a lake or sea.
  9. Organic lakes – Formed by the accumulation of plant and animal material.
  10. Anthropogenic lakes – Formed by human activities such as the construction of dams and reservoirs.
  11. Meteorite (extraterrestrial impact) lakes – Formed by meteorite impacts.
Himalayas Khumbu Glacier Lake

Why do we drain lakes?

We drain lakes for a variety of different reasons. In some cases, it may be to reduce the risk of malaria or depth changes, create agricultural land, prevent annoying mosquito plagues, or restore the river’s flow. In other cases, it may be to provide power for a waterwheel, for irrigation purposes, or to make land or water available for agriculture. Draining a lake can also be done to create a reservoir or to create a whitewater course. Lakes are typically drained by diverting the water around them and allowing the water within the lake to flow out the outlet. However, this must be done carefully to avoid flooding downstream areas.


Different Methods of Draining a Lake

Drying

One way to drain a lake is by drying it out, which involves diverting the water flowing into the lake and letting the water within it flow out the outlet. Usually, this is done by building a dam or other obstruction around the lake to contain the water and then releasing it slowly over time. This is often used to reclaim land for agriculture or prevent annoying mosquito plagues. In other cases, collapsed sediment plugs in the lake bed can be used to funnel the water into the aquifer, allowing the lake to be drained virtually completely.

Pumping

Pumping effectively drains a lake, particularly when a river or other water source feeds the lake. The process involves redirecting the water flow to a drainage or pump system to draw down the lake level. The process requires specific engineering and planning considerations to ensure that the lake is not drained too quickly, as this could cause damage to the lake, its surroundings, or the surrounding ecosystems. The planning process should also consider the impact on downstream areas, as a sudden influx of water may cause flooding. In addition, the lake should be monitored to ensure the lake level is falling steadily and not becoming overly turbid from the influx of sediment. Ultimately, a properly designed and maintained pump system can safely and effectively drain a lake.

Gravity drainage

Gravity drainage is a method of draining a lake by using the natural flow of the water to carry it away. This can be done by redirecting the water flowing into the lake or by opening the drain valve at the lake’s outlet to allow the water to flow out. To ensure a proper flow of water out of the lake, the water level should be lowered slowly—at no more than one foot per week—to prevent the build-up of hydrostatic pressure in the upstream slope of the dam. Additionally, a headwall should be installed near the outlet of the lake drain conduit to reduce erosion. A rock riprap or other slope protection layer should be applied to further reduce erosion in the drain area. Finally, for accessibility and to prevent vandalism, the control platform should be onshore or provided with a bridge or other structure.

Drained Lake - water drained for Dam repairs

FAQs

What kind of lake can be drained?

Lakes can be classified into two primary categories based on whether they can be drained: natural and artificial lakes. Natural lakes form by natural processes, such as glaciers or river erosion, and cannot be drained. Artificial lakes are man-made, usually by blocking up a small creek or river with a concrete and rebar dam and then allowing water to fill the area. Artificial lakes can be drained by diverting the water around them and allowing the water within the lake to flow out the outlet.

Where does the drained water go?

When a lake is drained, the water typically flows out through its outlet and is diverted around it. Sometimes, water may be released back into the waterway from or into a gorge to prevent flooding downstream. In other cases, the water may be released into a gorge where the steep sides of the gorge keep it relatively contained. In some cases, attempts have been made to drain the lake for agricultural land or prevent annoying mosquito plagues. In these cases, the drained water is funneled into the aquifer, which can completely drain the lake.

What are the effects of draining a lake?

The effects of draining a lake can be wide-reaching and have both positive and negative impacts. Positive effects of draining a lake include reducing mosquito populations, creating agricultural land, controlling water levels for flood prevention, and providing access to perform repairs and maintenance. The negative effects of draining a lake include decreased habitat for fish and animals, decreased water quality, and disruption of the natural cycle of flooding and drought. In addition, drained lakes can be subject to increased erosion, sedimentation, and an increased risk of flooding. Furthermore, lake drainage can cause the collapse of ice lenses in permafrost environments, leading to rapid drainage and potentially damaging infrastructure.

What is the difference between a sinkhole and a lake drain system?

The main difference between a sinkhole and a lake drain system is that a sinkhole is a natural phenomenon, while a lake drain system is an artificial structure. A sinkhole is a geological formation that occurs when surface water accumulates in a depression and erodes the rocks and soils beneath it, forming a large hole. A lake drain system, on the other hand, is a man-made structure that is designed to regulate the water level in a lake or reservoir. Unlike a sinkhole, the lake drain system can be controlled to release water when necessary. The lake drain system typically includes a stem, valve, outlet pipe, and related appurtenances, monitored and maintained regularly to ensure they function properly.