CSLB C-27 Landscaping ContractorSite Preparation and DrainageHard
A landscape contractor is installing a catch basin as part of a surface drainage system for a paved area. The catch basin is designed to collect runoff from a significant impervious surface. To ensure the long-term effectiveness and minimize maintenance, what is the most important feature the catch basin should possess?
- AA large, easily accessible sump at the bottom.
- BA decorative cast-iron grate for aesthetic appeal.
- CAn overflow pipe connected to the sanitary sewer system.
- DConnection to a stormwater retention pond.
Show answer & explanationAnswer & explanation
Correct answer: A. A large, easily accessible sump at the bottom.
A large, easily accessible sump (or sediment trap) at the bottom of a catch basin is crucial. It allows sediment, debris, and pollutants to settle out before entering the main drainage pipe, preventing clogs downstream and facilitating easier maintenance.
Why the other options are wrong
- B. While aesthetics are a consideration, a decorative grate does not contribute to the functional effectiveness and maintenance efficiency of the catch basin.
- C. Connecting to a sanitary sewer is generally prohibited for stormwater runoff due to environmental regulations and potential for overwhelming the sewer system; stormwater should go to a storm drain or retention system.
- D. Connecting to a retention pond is part of the overall drainage system design, but it's not a feature *of the catch basin itself* that ensures its internal effectiveness and minimizes maintenance.
Catch Basin Sump
A chamber at the bottom of a catch basin designed to collect sediment and debris, preventing it from entering the drainage pipes.
- Prevents downstream pipe clogging.
- Requires regular cleaning for effectiveness.
- Accessibility is key for maintenance.
Memory trick: A CATCH basin needs a deep SUMP to stay CLEAN.