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Question

Difficulty: HardExtracting Supporting Details and Facts

Listen to the following transcript from an academic presentation on ancestral Andean hydrological engineering:

"To mitigate severe seasonal water deficits in coastal metropolitan areas such as Lima, hydrological researchers in Peru are turning to pre-Inca engineering systems known as 'amunas.' Developed primarily by the Wari culture around 700 CE, amunas are intricate networks of unlined stone canals carved along high-altitude mountain slopes. Rather than collecting runoff into conventional open-air surface reservoirs, which suffer from high rates of evaporation and sediment accumulation, the amunas deliberately channel excess precipitation during the torrential rainy season—typically from October to April—directly into permeable geological fractures along the upper mountainsides. The water slowly percolates through the porous subterranean rock strata over a delayed transit period of four to eight months, ultimately emerging during the arid summer dry season at natural lower-elevation springs known as 'puquios.' Recent quantitative assessments of a restored 1.4-kilometer canal section in the community of Huamantanga demonstrated that the system successfully delayed and recovered approximately 180,000 cubic meters of water annually, providing a cost-effective, decentralized buffer against modern climate volatility."

According to the presentation, what specific mechanism allows the traditional amunas infrastructure to supply water during the arid dry season?

  1. A
    By storing high-altitude glacial meltwater in sealed stone surface reservoirs to prevent evaporation.
  2. By directing torrential seasonal runoff into permeable rock fissures so it filters slowly underground before emerging in downstream springs months later.Answer
  3. C
    By establishing municipal regulatory frameworks to permanently reduce per capita water consumption in coastal metropolitan areas.
  4. D
    By utilizing motorized pumps to extract deep groundwater during unexpected climate emergencies.

Answer

Directing torrential seasonal runoff into permeable rock fissures so it filters slowly underground before emerging in downstream springs months later.
The presentation explicitly details that the amunas operate by routing rainy-season precipitation into permeable mountain fractures, where slow underground filtration over a period of four to eight months ensures that water surfaces at lower-elevation natural springs ('puquios') during the dry season.

Step-by-Step Solution

1
Identify the target question focus
The question asks for the specific physical mechanism that enables the amunas system to delay and release water during the dry season.
Extracting supporting details requires isolating explicit causal and mechanical facts from background context.
2
Locate relevant supporting statements in the transcript
The speaker explains that canals channel excess rainy season precipitation directly into permeable geological fractures, where water slowly percolates through porous rock strata over 4 to 8 months before emerging at lower-elevation springs ('puquios').
This provides the factual evidence explaining how the temporal delay in water availability is achieved.
3
Evaluate the answer choices against the factual evidence
The choice describing the redirection of runoff into permeable rock fissures to filter underground over months matches the stated mechanism exactly, while other options alter physical facts or substitute broad policy concepts.
The correct response must align strictly with the technical supporting details provided by the speaker.

Key Concept

Extracting Supporting Details and Facts from Oral Presentations
Estimated Time:2m 0s
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Topics

Extracting Supporting Details and Facts

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