Healthy Shorelines for Healthy Lakes

The Highs and Lows of Fluctuating Water Levels


Water levels in lakes can fluctuate due to natural processes such as precipitation, runoff, and evaporation, though changes may not occur immediately. Lakes that are on controlled systems can also experience fluctuating water levels.
Whatever the cause may be, there are pros and cons to both high and low water levels on the environment, economy, as well as people’s activities and structures.

High Water Level Pros:

  • Can benefit municipal water users, hydropower generation, shipping, and recreational boating. However, if water levels are too high and currents are too fast, it can also create issues for these activities.
  • Intermittent high water levels are needed to maintain wetland productivity and health. Extreme high levels however can interfere with these benefits.
  • With higher water, wetlands reach further inland and become flooded to greater depths, which is periodically beneficial.
  • Degraded soils can be restored during high water as rivers push nutrients and sediment onto agricultural properties.

High Water Level Cons:

  • Buildings close to shore can be impacted by flooding.
  • Docks, boat houses, boat ramps, marinas, and shorelines can be flooded.
  • There can be increased erosion.
  • Extreme water flow through a channel can intensify soil erosion which can harm wildlife habitat and impact water quality.

Low Water Level Pros:

  • Can benefit those with short and low docks.
  • Can benefit those with buildings close to shore.
  • Erosion rates typically decline.
  • Low water levels can encourage dormant aquatic seeds to germinate.
  • Vegetation associated with wetlands can reach further into the lake which can create new fish habitat when water levels return to normal.

Low Water Level Cons:

  • Municipal users can be impacted by low water levels if the water intakes are above the surface of the water.
  • Docks and boat launches may not extend far enough for recreational boaters.
  • Boaters need to be careful of navigation hazards.
  • Low water levels attributed to dry conditions can impact food webs and can harm the survival of aquatic species.

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