This document is the 703 Retention-Detention System (Riser and Cleanout) Detail. Cross sections with descriptions and dimensions provided.

The Section A-A details shows load bearing concrete collar, frame and grate, corrugated HDPE riser, undisturbed earth, class I or II compacted material and bedding class.

Section B-B details the lid, solid wall HDPE cleanout, load bearing concrete collar, undisturbed earth, class I or II compacted material and bedding class.

A third cross section shows the undisturbed earth, riser, cleanout and class I or II compacted material.

Notes state that Class I backfill is required around 60” diameter fittings and load bearing concrete collar shall be constructed in traffic areas such that the live load in transmitted to the surrounding soil and not directly on the riser.