CSLB C-27 Landscaping ContractorSite Preparation and DrainageEasy
A landscape contractor is installing a dry well to manage stormwater runoff from a portion of a residential property. What is the primary functional requirement for the soil surrounding and beneath the dry well?
- AHigh clay content to prevent water migration.
- BGood permeability to allow rapid infiltration.
- CHigh organic matter content for nutrient retention.
- DLow permeability to slow down infiltration.
Show answer & explanationAnswer & explanation
Correct answer: B. Good permeability to allow rapid infiltration.
A dry well functions by allowing stormwater to slowly infiltrate into the surrounding soil. Therefore, the primary functional requirement for the soil surrounding and beneath a dry well is good permeability, enabling rapid and efficient absorption of water.
Why the other options are wrong
- A. High clay content would impede infiltration, causing the dry well to fail or overflow.
- C. High organic matter content is good for planting but not the primary requirement for a dry well's ability to infiltrate water.
- D. Low permeability would prevent the dry well from functioning effectively by not allowing water to drain.
Dry Well Soil Permeability
The ability of soil to allow water to pass through it, a critical factor for the effective function of a dry well.
- Requires highly permeable soil.
- Allows stormwater to infiltrate into the ground.
- Prevents surface runoff and pooling.
- Percolation test is necessary to assess suitability.
Memory trick: Permeable Paths Permit Puddles to Pass.