CSLB C-27 Landscaping ContractorSite Preparation and DrainageEasy
A landscape contractor is tasked with installing a dry well as part of a stormwater management system for a residential property. Which of the following soil types would be most suitable for the effective operation of a dry well?
- ASilty clay loam
- BHeavy clay
- CSandy loam
- DCompact urban fill
Show answer & explanationAnswer & explanation
Correct answer: C. Sandy loam
Dry wells rely on the surrounding soil's ability to absorb and infiltrate water. Sandy loam soils have good permeability and drainage characteristics, making them ideal for dry well installations. Heavy clay and compacted soils have low permeability and would significantly hinder the dry well's effectiveness.
Why the other options are wrong
- A. Silty clay loam has moderate to low permeability; while better than heavy clay, it's not ideal for optimal dry well performance.
- B. Heavy clay has very low permeability, which would prevent the dry well from effectively infiltrating water into the ground.
- D. Compact urban fill often consists of mixed materials with varying and usually low permeability, making it unsuitable for dry wells.
Dry Well Soil Suitability
Dry wells are most effective in highly permeable soils like sandy loam, which allow for rapid infiltration of stormwater.
- Requires good soil permeability for proper function.
- Unsuitable in heavy clay or highly compacted soils.
- Infiltrates collected stormwater into the ground.
Memory trick: A dry well needs 'sandy' soil to drink water.