Katmai National Park Water Temperature: Exploring the Factors and Impacts

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The water temperature in Brooks River, located within Katmai National Park, exhibits significant variability during the summer months. The typical water temperature range in Brooks River during the summer is between 44°F (6.7°C) and 69°F (21°C), with the highest temperatures recorded in August.

What Factors Influence the Water Temperature Variability in Katmai National Park?

katmai national park water temperature
Image Credit: Wikimedia

Several factors contribute to the variability in water temperature in Brooks River:

  1. Weather Patterns: Clear and sunny weather can warm the water above a shallow shelf in Lake Brooks, while cool and cloudy weather can drop the temperature. Wind across Lake Brooks can also stir the lake, breaking the thermocline between warm surface water and cold deeper water.

  2. Underwater Topography: The shallow shelf in Lake Brooks, which is only a few feet deep, allows for significant warming of the water during sunny periods. This warmed water then flows into Brooks River, influencing its temperature.

  3. Day Length: The long days during the summer solstice in Katmai National Park (almost 19 hours of daylight) contribute to the warming of the water in Lake Brooks and subsequently in Brooks River.

How Does the Water Temperature Affect the Salmon Spawning Cycle in Katmai National Park?

katmai national park water temperature

The water temperature in Brooks River significantly affects the spawning cycle of salmon:

  1. Spawning Delay: Sockeye salmon in Brooks River delay their spawning until late August and September when the water temperature cools down. This ensures that the eggs incubate at a slower rate, allowing the fry to hatch when food is more abundant.

  2. Incubation Time: Warmer water temperatures can decrease the incubation period for salmon eggs, potentially causing them to hatch too early when food is scarce. Cooler water temperatures slow down the incubation process, allowing the fry to hatch at a more favorable time.

  3. Egg Mortality: Water temperatures above 57°F (14°C) can significantly increase egg mortality rates for sockeye and coho salmon.

What are the Relevant Data and References for Katmai National Park Water Temperature?

  • Average Water Temperature: The average water temperature in Katmai National Park is around 55°F (13°C) during the warmest month of August.

  • Temperature Thresholds: Water temperatures should not exceed 13°C for spawning or incubating salmon, 15°C for migrating or rearing salmon, and 20°C at any time to support aquatic life.

References:

  1. FitzNaturalist. (2017, July 26). Brooks River Water Temperature | Wandering at Large. Retrieved from https://fitznaturalist.com/2017/07/26/brooks-river-water-temperature/

  2. National Park Service. (2023, December 13). Water Quality in Southwest Alaska. Retrieved from https://www.nps.gov/articles/waterqualityswan.htm

  3. Weatherspark. (n.d.). Katmai National Park Climate, Weather By Month, Average. Retrieved from https://weatherspark.com/y/150332/Average-Weather-in-Katmai-National-Park-Alaska-United-States-Year-Round

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