872SEDIMENT BASIN

872.1DESCRIPTION—This work is the construction, maintenance, removal and/or conversion of a sediment

basin to a permanent stormwater management facility.

872.2MATERIAL—

other approved material of adequate size and length.

• Rock. Section 850.2(a)

• Geotextile. Class 4, Type A. Section 735

872.3CONSTRUCTION—As shown on the Standard Drawings, at the location indicated or directed , and

as follows: As specified in Section 201.3, clear and grub the storage area and embankment foundation area site. Excavate the key trench for the full length of the embankment. Excavate the emergency spillway as indicated. Install the outlet protection, outlet pipe with the anti-seep collar attached, and outlet structure at the location indicated. When indicated, construct the temporary riser pipe assembly, as specified in Section 874.3. When concrete anti-seep collar is specified, construct collar as specified in the applicable parts of Section 1001.3. When the sediment basin is located in a permanent stormwater management facility and a concrete outlet structure is indicated, construct concrete outlet structure as specified in Section 875.3. Construction of the embankment and trench before placing the pipe is not required. Do not use coarse aggregate as backfill material around the pipe. Backfill the pipe with suitable embankment material to prevent embankment leakage along the pipe. Construct outlet protection of the type indicated at outlet end of pipe, as specified in Section 85 1.3. Place the embankment material, as specified in Section 206.3. If required, obtain borrow excavation for the formation of the embankment, as specified in Section 205. Apply seeding and soil supplements, as specified in Section 804.3. Mulch, if required, as specified in Section 805.3. Install and maintain cleanout stake as required, as indicated, or as directed. Inspect sediment basin after each runoff event. Remove accumulated sediment as specified in Section 861.3 and repair as required or as directed. When the tributary area to the sediment basin is stabilized, or the basin is no longer required, or when directed, satisfactorily recondition the site as follows:

• Temporary Sediment Basin: Fill in excavated areas, removing embankments, riser pipe assemblies, corrugated metal pipe, and anti-seep collars, or as directed. Restore the areas as specified in Section

105.14. Satisfactorily dispose of removed materials

• Sediment Basin located in a Permanent Stormwater Management Basin area: Remove accumulated sediment and restore basin to final contouring as indicated, stabilize disturbed areas as indicated, remove temporary orifice covers, temporary standpipes, affix permanent stormwater management features as specified in Section 875.3, as indicated, or as directed. Satisfactorily dispose of removed materials.

872.4MEASUREMENT AND PAYMENT—

For the type indicated.

For the type indicated.

Section 205.4.

For the type indicated.

For the type indicated.

For the type indicated.

Section 850.4

Section 212.4