Podcast
Questions and Answers
Which of the following statements about lakes is true?
Which of the following statements about lakes is true?
A reservoir is always a natural lake.
A reservoir is always a natural lake.
False
What is the largest salt-water body in the world?
What is the largest salt-water body in the world?
Caspian Sea
The formula for calculating the volume of a lake is Volume = Surface Area x ________.
The formula for calculating the volume of a lake is Volume = Surface Area x ________.
Signup and view all the answers
Match the following lakes with their characteristics:
Match the following lakes with their characteristics:
Signup and view all the answers
What does a hypsographic curve represent?
What does a hypsographic curve represent?
Signup and view all the answers
Lotic refers to standing water bodies like lakes.
Lotic refers to standing water bodies like lakes.
Signup and view all the answers
How deep is Kootenay Lake at its deepest point?
How deep is Kootenay Lake at its deepest point?
Signup and view all the answers
The average discharge of Kootenay River at Kootenay Lake is ________ m3/s.
The average discharge of Kootenay River at Kootenay Lake is ________ m3/s.
Signup and view all the answers
Which lake is known as the largest freshwater lake in the world?
Which lake is known as the largest freshwater lake in the world?
Signup and view all the answers
What does the Shoreline Regularity Index (SRI) measure?
What does the Shoreline Regularity Index (SRI) measure?
Signup and view all the answers
The photic zone is the area where photosynthesis occurs more than respiration.
The photic zone is the area where photosynthesis occurs more than respiration.
Signup and view all the answers
What is the Hydraulic Residence Time (HRT)?
What is the Hydraulic Residence Time (HRT)?
Signup and view all the answers
The minimum value of the Shoreline Regularity Index (SRI) is _____ .
The minimum value of the Shoreline Regularity Index (SRI) is _____ .
Signup and view all the answers
Match the lake characteristic with its correct description:
Match the lake characteristic with its correct description:
Signup and view all the answers
What is Kootenay Lake's SRI value?
What is Kootenay Lake's SRI value?
Signup and view all the answers
Reservoirs have smooth shorelines because they consist of flooded river valleys.
Reservoirs have smooth shorelines because they consist of flooded river valleys.
Signup and view all the answers
The ____ consists of unceded Indigenous lands or public land in BC.
The ____ consists of unceded Indigenous lands or public land in BC.
Signup and view all the answers
What is the average Secchi Disk depth measurement for Crater Lake?
What is the average Secchi Disk depth measurement for Crater Lake?
Signup and view all the answers
The equation for Hydraulic Residence Time (HRT) includes which factors?
The equation for Hydraulic Residence Time (HRT) includes which factors?
Signup and view all the answers
Study Notes
Lake Definitions
- There is no official distinction between a lake and a pond.
- To determine if a body of water is a lake or a pond, consider if light reaches the bottom at the deepest point, if the water body is relatively uniform, and if the waves are smaller than 30 cm in height.
- Lakes and rivers are distinct, but there is overlap. Lakes are lentic and rivers are lotic ecosystems.
- Reservoirs can be a combination of lakes, rivers, and reservoirs.
- Reservoirs are artificial lakes filled by river inflow.
Lake Morphology
-
Surface Area:
- Measured using maps or remote sensing techniques.
- Caspian Sea is the largest saltwater body.
- Aral Sea is a shrinking saltwater body.
- Lake Superior is the largest freshwater body.
-
Depth:
- Measured using soundings (weighted line) or sonar.
- Bathymetry is a map of the lake bottom.
- Mean depth (z) is the average depth of the lake.
- Volume is calculated by multiplying surface area by mean depth or by summing the product of area and depth of horizontal segments.
-
Hypsographic Curve:
- Represents the depth-area distribution of the lake.
- Shows the amount of each depth zone, useful for assessing biological reproduction potential.
-
Bathymetric Map:
- A map of the lake bottom topography.
- Shows the depth contours of the lake.
Kootenay Lake
-
Located in the Kootenay River Basin, which is 50,298 km2.
-
The Kootenay River has a stream order of 7.
-
Kootenay Lake Basin is 31,264 km2, with 174 inlets and one outlet (Kootenay River).
-
Average discharge of the Kootenay River at Kootenay Lake is 782 m3/s.
-
Dimensions:
- Length: 104 km.
- Width: 3-5 km.
- Surface Area: 421 km2 or 421,730,000 m2.
- Perimeter: 405 km or 405,082 m.
- Deepest Point: 150 m.
- Average Depth: 94 m for the main lake, 10 m for West Arm.
-
Volume:
- Calculated as Area x Mean Depth.
- Volume = 421,730,000 m2 x 94 m = 39,642,620,000 m3.
Foreshore
- Land between the high and low watermarks, including beaches.
- In BC, foreshore is either unceded Indigenous lands or public land, not private land.
Shoreline Characteristics
- Reservoirs have jagged shorelines due to the flooding of river valleys.
Shoreline Regularity Index (SRI)
-
Measures the deviation of a lake's shape from a circle.
-
Minimum is 1.0 for circular lakes.
-
Higher values (4+) indicate irregular shapes like reservoirs or shoestring shapes.
-
High SRI and shallow depths create extensive littoral zones.
-
Calculation:
- SRI = Shoreline Length / Circumference of Area.
- For Kootenay Lake: SRI = 405,082 m / (2√421,730,000π) = 5.56.
Hydraulic Residence Time (HRT)
-
The average amount of time water spends in a lake.
-
Important for pollution studies and nutrient regimes.
-
Calculations:
- HRT (years) = Volume (m3) / Q (m3/s) x 1 year / 31,536,000 s/year.
- For Kootenay Lake: HRT = 39,642,620,000 m3 / 782 m3/s x 1 year / 31,536,000 s/year = 1.6 years.
- Alternatively, HRT (years) = Volume (Lake) (m3) / (Basin Area (m2) x Avg. Precip (m/year) x 0.85).
- For Kootenay Lake: HRT = 39,642,620,000 m3 / (31,264,000,000 m2 x 0.9 m x 0.85) = 1.66 years.
Light Penetration
-
Photic Zone:
- Surface down to where 1% of light penetrates.
- Zone of net oxygen production (photosynthesis > respiration).
- Depth depends on water clarity.
-
Aphotic Zone:
- Bottom of the photic zone to the bottom of the lake.
- More carbon dioxide is produced than oxygen (respiration > photosynthesis).
Water Transparency
- Measured using Secchi Disk Depth.
- Secchi Disk Depth is the depth at which the disk disappears and then reappears.
- Photic Zone is roughly 2.5 times the Secchi Disk Depth.
Crater Lake
- Average Secchi Disk Depth of 1-10 meters.
- Crater Lake has a Secchi Disk Depth of 43 meters.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the essential definitions and morphological characteristics of lakes in this quiz. Learn about the distinctions between lakes and ponds, measurement techniques, and notable lakes around the world. Test your knowledge on the features that define these important aquatic ecosystems.
