Section 90-134. Same--Information required.
The following information shall be submitted as part of the development plan or application for a stormwater permit:
(1) A recent aerial photograph taken not more than three years before the date of application, which encompasses the project area and all land areas that contribute to the runoff flow. The scale shall not exceed one inch equals 2,000 feet.
(2) A topographic map of the site clearly showing the location, identification and elevation of benchmarks, including at least one benchmark for each major water control structure. Unless otherwise approved by the city engineer, the minimum contour interval of the topography map shall be one foot. The map shall be signed and sealed by a registered surveyor.
(3) A detailed overall project area map showing existing hydrography and runoff patterns and the size, location, topography and land use of any offsite areas that drain onto or from the project area. The scale shall not exceed one inch equals 200 feet and shall be prepared on a 24-inch by 36-inch sheet.
(4) A current land use map.
(5) A soils map of the site.
(6) Specify the seasonal high-water table and low-water table elevations.
(7) A map of vegetative cover, including adjacent wetlands.
(8) A map showing the location of all soil borings or percolation tests. Percolation tests shall be conducted if the stormwater management system will use swales, percolation filtration or exfiltration designs.
(9) A map showing the flood hazard classification of the project site and its immediate environs.
(10) Grading plans specifically including perimeter grading.
(11) paving, road and building plans showing the location, dimensions and specifications of roads and buildings, including elevations.
(12) An erosion and sedimentation control plan that describes the type and location of control measures, the timing of their implementation and maintenance provisions.
(13) The description, assumptions and calculations of the proposed stormwater management system, including:
a. Channel, direction, flow rate and volume of stormwater inputs and outputs for the site, with a comparison to natural or existing conditions.
b. detention and retention areas, indicating wet or dry, including plans for the discharge of contained waters, maintenance plans and predictions of surface water quality changes.
c. Areas of the site to be used or reserved for percolation, including an assessment of the impact on groundwater quality.
d. Location of all water bodies to be included in the surface water management system (natural and artificial) with details of hydrography, side slopes, depths, cross sections and water surface elevations and hydrographs.
e. Any offsite easements required for the proper functioning of the system.
f. Identify drainage basin or watershed boundaries and show where offsite waters are routed onto or around the project.
g. right-of-way and easements for the system, including locations and a statement of the nature of the reservation for all areas to be reserved.
h. The location of offsite water resource facilities, such as surface water management systems or wells that might be affected by the proposed project, showing the names and addresses of the owners of the facilities.
(14) Storm sewer tabulations, including but not limited to the following:
a. Locations and types of structures.
b. Types, diameters, slope and lengths of line.
c. drainage sub areas tributary to each structure.
d. Runoff coefficient per sub area.
e. Time of concentration to structure.
f. Hydraulic gradient for the 25-year frequency storm event.
g. Estimated receiving water (tailwater) elevations, with sources of information, if available.
Secs. 90-135--90-145. Reserved.
DIVISION 3. PERFORMANCE STANDARDS