A. 
General. All pipe used for storm drainage shall be either Class 4 reinforced concrete pipe (RCP) or asphalt-coated corrugated metal pipe (ACCMP). Reinforced concrete pipe shall be used except as otherwise permitted by the Commission as specified herein. Where the bedding of the pipe is to be in unstable material or where the gradient of the pipe exceeds 8%, ACCMP shall be used in lieu of RCP.
B. 
Minimum cover. The minimum cover over all storm drainage within the right-of-way shall be three feet. Where conflicts with other subsurface facilities require, and with the approval of the Commission, pipe may have as little as 18 inches of cover, but in such cases extra-strength Class 5 RCP shall be used.
C. 
Slotted or perforated storm drains. Where water is encountered in the pipe trenches, or where underdrains are required under § 480-68, storm drains shall either be slotted RCP or perforated ACCMP.
D. 
Additional underdrains. Where additional underdrains are deemed necessary in locations not requiring other storm drainage, six-inch perforated ACCMP shall be provided.
E. 
Materials and methods. Materials and construction methods shall conform to the requirements of the State Standard Specifications for Culverts and Underdrains and Outlets.
A. 
General. Catch basins, manholes, and drop inlets shall be constructed in accordance with the Standard Detail Drawings.
B. 
Materials and methods. Materials and construction methods shall conform to the requirements of the State Standard Specifications for Catchbasins, Manholes and Drop Inlets.
A. 
General. Endwalls shall be constructed in accordance with the Standard Detail Drawings.
B. 
Materials and methods. Materials and construction methods shall conform to the requirements of the State Standard Specifications for Endwalls.
Riprap materials and construction methods shall conform to the applicable requirements of the State Standard Specifications for Riprap.
A. 
General. Seeding, sodding, burlap erosion protection and other methods of stabilizing beds and banks of open channels shall conform to the applicable materials and construction methods specified in the state standard specifications for the particular method approved for use.
B. 
Material and methods where no state standard. Where the state standard specifications do not cover the stabilization method approved for use, materials and construction methods shall conform to the standards and specifications contained in the most current edition of the Erosion and Sediment Control Handbook for Connecticut as published by the United States Soil Conservation Service.
[Amended 6-3-2008]
Bridges, box culverts, retaining walls and other special drainage structures shall be designed and constructed in accordance with the most current applicable design criteria and standards of the Connecticut Department of Transportation.