CAC Stream and Waterfall Construction 2 — Questions and Answers
Question 1: What is the function of a weir box (spillway) at the top of an aquascape waterfall?
- To filter debris before water enters the stream
- To create a uniform, consistent water sheet over the falls (Correct answer)
- To aerate water before it reaches the pond
- To measure total water volume in the system
Correct answer: To create a uniform, consistent water sheet over the falls
A weir box distributes water evenly across its lip, producing a consistent sheet of water cascading over the falls for a polished aesthetic.
Question 2: Which factor most directly determines the pump size needed for a waterfall and stream feature?
- The color of liner used
- The width of the waterfall spillway and total head height (Correct answer)
- The number of plants in the adjacent pond
- The ambient temperature of the installation site
Correct answer: The width of the waterfall spillway and total head height
Pump sizing is determined by calculating the desired flow rate (typically 100–150 GPH per inch of waterfall width) multiplied against the total head height.
Question 3: What is the purpose of 'keying in' a waterfall boulder into the liner during stream construction?
- To prevent the boulder from sliding downhill and to seal water against the rock face (Correct answer)
- To satisfy local building codes for structural stability
- To provide a mounting point for underwater lighting
- To anchor the liner to prevent floating
Correct answer: To prevent the boulder from sliding downhill and to seal water against the rock face
Keying in a boulder means pressing it into the liner so water hugs the rock face and flows over rather than channeling around or behind it.
Question 4: In multi-tier waterfall construction, what is the preferred method to transition water between tiers to minimize splash loss?
- Overlapping liner sections with a 12-inch plunge pool between tiers (Correct answer)
- Leaving gaps between tiers for natural waterfall effect
- Using concrete channels between each tier
- Installing micro-perforated pipe between tiers
Correct answer: Overlapping liner sections with a 12-inch plunge pool between tiers
A small plunge pool shelf with overlapping liner between tiers catches water and redirects it to the next fall, reducing splash and water loss.
Question 5: Which rock type is most commonly recommended for aquascape waterfall and stream construction due to its natural appearance and water-safe properties?
- Limestone
- Fieldstone or granite boulders (Correct answer)
- Sandstone
- Quartzite
Correct answer: Fieldstone or granite boulders
Fieldstone and granite boulders are water-safe, durable, and provide the natural, weathered appearance suited to aquascape aesthetics.
Question 6: When sizing a stream for a residential aquascape, what is the general rule for stream width relative to waterfall width?
- The stream should be twice as wide as the waterfall
- The stream width should be similar to or slightly narrower than the waterfall (Correct answer)
- The stream should always be at least 4 feet wide regardless of the waterfall
- Stream width is irrelevant to waterfall width
Correct answer: The stream width should be similar to or slightly narrower than the waterfall
Keeping stream width similar to or slightly narrower than the waterfall maintains consistent visual proportion and efficient water flow throughout the feature.
Question 7: What is the primary reason gravel and cobble are placed on the stream bed liner after construction?
- To add structural support to the liner
- To promote beneficial bacteria colonization and improve aesthetics (Correct answer)
- To increase water flow speed
- To prevent liner UV degradation
Correct answer: To promote beneficial bacteria colonization and improve aesthetics
Gravel and cobble on the stream bed provide surface area for beneficial bacteria that aid biological filtration and give the stream a natural appearance.
CAC Stream and Waterfall Construction 2
What is the function of a weir box (spillway) at the top of an aquascape waterfall?