(a) Storm water detention/retention as-built plans shall be submitted to the Building Department upon the completion of installation of the detention/retention system. The developer shall submit two copies of the as-built plans signed and sealed by a professional land surveyor. The as-built plans shall contain, at a minimum, the following information:
(1) Topographic Plan that shows as-built grades (contours) of the detention/retention basin.
(2) The size, length and material of conduits installed if subsurface detention methods were used.
(3) Elevations of all outlet structures.
(4) Size of all discharge features.
(5) Verify existence of adjustable gate valves, when required.
(6) Spillway and weir cross-sections.
The as-built information shall be clearly identified on the drawings. As-built information shall be blocked in, such as 985.25, or indicated in a different color than that of the design information. As-built elevations shall be based on NAVD88.
(b) Hydraulic analysis of the storm water detention/retention system for as-built conditions shall be submitted to the Building Department upon completion of installation of the detention/retention system. The hydraulic analysis shall be based on the information obtained as part of the storm water detention/retention as-built survey. The as-built sizes and elevations of the outlet control structure(s) shall be used in the as-built hydraulic analysis. Storage volumes calculated from the as-built survey shall be used for all flood routing analysis. The as-built hydraulic analysis shall utilize the same software program that was used for the design analysis. Parameters used for the as-built hydraulic analysis such as rainfall depths, runoff coefficients and times of concentration shall be the same as that used for the design analysis unless otherwise approved by the Building Department. Two copies of the as-built hydraulic analysis shall be submitted to the Building Department. The two copies shall be signed and sealed by a professional engineer and shall include a statement indicating that the detention/retention system satisfies the design criteria outlined in the various sections.
(Ord. 10080-2017. Passed 6-20-17.)