[Ord. No. 24-13956, 5-20-2024]
No person shall alter the contours of any real property within the City, whether subdivided or not, so as to change the flow of water into or through any ditch, drain, or drainage structure without obtaining a permit and complying with the provisions of this Chapter.
[Ord. No. 24-13956, 5-20-2024]
A. 
Material And Construction Standards.
1. 
Storm pipes shall be protected from excessive bearing pressures by placing them outside the forty-five-degree influence zone of building structures unless an engineering calculation shows the pipe material or soil condition to be adequate for the subjected load.
2. 
Pipes on slopes of twenty percent (20%) or greater shall be anchored securely with concrete anchors or equal to prevent the pipe from creeping downhill.
3. 
Pipes or structures constructed on fill shall be stable and protected against settlement by compacting fill material to ninety-five percent (95%) of the modified proctor maximum dry density, per AASHTO T180 (ASTM D1557).
4. 
Pipes thirty-six (36) inches or larger may be placed on a curved alignment utilizing alignment radii established by the pipe manufacturer.
5. 
The receiving surface where pipes discharge shall be protected from erosion by evaluating the discharge velocity for the 10-year design storm. The use of energy-dissipating devices may be necessary to reduce the velocity to acceptable levels for the receiving surface.
6. 
A manhole, inlet or junction box shall be located at changes in pipe size, grade, alignment or material.
7. 
The angle between influent and effluent pipes shall be not less than ninety degrees (90°) and the drop between inverts shall be not less than one-tenth (0.1) foot.
8. 
Manhole and inlet castings located in travel ways shall be capable of withstanding traffic loads and shall be constructed flush with the finished surface.
9. 
All materials and appurtenances for stormwater management systems shall conform to current standards of the American Society for Testing and Materials (ASTM).
10. 
Manholes shall be precast or cast-in-place concrete, brick, concrete block, with concrete or brick risers and approved manhole covers.
11. 
A new drainage channel or pipe shall intersect an existing drainage channel at a maximum angle of sixty degrees (60°).
12. 
All trenches under roadway pavement shall be backfilled with Missouri Department of Transportation (MoDOT) Type I aggregate in six-inch layers and compacted to ninety-five percent (95%) of the modified proctor maximum dry density per AASHTO T180 (ASTM D1557).
13. 
All piping shall be bedded per the manufacturer's requirements.
14. 
Grated inlets will not be allowed without special approval by the City Engineer.
15. 
All materials used in the construction of storm sewers shall be subject to inspection and approval of the City Engineer.
16. 
Acceptable pipe material is as follows.
a. 
Reinforced concrete pipe shall conform to the requirements of the Specifications for Reinforced Concrete Culvert, Storm Drain and Sewer Pipe, ASTM C76. Strength class or classes shall be as required per design specifications of the latest Edition of the Concrete Pipe Handbook as published by the American Pipe Association.
b. 
Corrugated metal pipe shall conform to the requirements of AASHTO M36, Standard Specification for Zinc Coated (Galvanized) Pipe, or the Standard Specifications for AASHTO M196 Corrugated Aluminum Pipe. Structural design requirements shall be per the latest Edition of the Handbook of Steel Drainage and Highway Construction Products, as published by the American Iron and Steel Institute.
c. 
Corrugated polyethylene pipe shall conform to the requirements of AASHTO M294, Standard Specifications for Corrugated Polyethylene Pipe. All polyethylene pipe should be installed according to ASTM D2321, Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-Flow Applications.
d. 
Dual wall and triple wall polypropylene pipe shall conform to the requirements of AASHTO M330, Standard Specification for Polypropylene Pipe, ASTM F2736 for sizes twelve (12) inches to thirty (30) inches and ASTM F2764 for sizes thirty (30) inches to sixty (60) inches. All polypropylene pipe shall be installed according to, ASTM F2321, Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-Flow Applications.
17. 
Reinforced concrete pipe and corrugated polypropylene complying with the provisions in Section 420.090(A)(16), above, shall be required under road pavement.
18. 
A minimum pipe size of twelve (12) inches is required to prevent blockage.
19. 
All construction details pertaining to stormwater drainage shall be in accordance with the Metropolitan St. Louis Sewer District requirements and standards for construction of sewers and drainage facilities, unless otherwise noted herein.
[Ord. No. 24-13956, 5-20-2024]
A. 
General. Sediment and erosion control will be accomplished by applying conservation practices that will reduce the potential for damage from these hazards. Control practices use trapping, filtering or diversion techniques to protect adjacent properties from land disturbance activities.
B. 
NPDES Stormwater Permits. Construction sites, where the area to be disturbed is one (1) acre or more, must apply for a stormwater discharge permit from the Missouri Department of Natural Resources. If required, the applicant must obtain and submit proof of an NPDES stormwater permit to the City, before plans will be approved. Permit requirements are set forth in 10 CSR20-6.200 of the Missouri clean water laws.
C. 
When Controls Are Required. Sediment and erosion control shall be implemented to prevent damage to off-site property, drainage facilities or watercourses. Generally, standard vegetative and structural practices, as specified below, that filter, divert or promote the settlement of sediment particles from storm runoff shall be provided in the following situations:
1. 
To prevent sediment-laden runoff from leaving disturbed areas.
2. 
To isolate disturbed areas from erosive surface runoff associated with significant undisturbed areas.
3. 
To protect storm drainage conveyance systems at operable inlets.
D. 
Types Of Controls. The stormwater management plan shall be selected, installed, operated and maintained to adequately control erosion, capture sediment and prevent pollution. To achieve these goals BMPs in accordance with the concepts and methods described in either of the following two (2) documents should be utilized.
1. 
Protecting Water Quality, MDNR (latest Edition).
2. 
Field Manual on Sediment and Erosion Control BMPs. Jerald S. Fifield, Ph.D., CPESC, Forester Press, latest Edition.
3. 
The developer is not limited to the use of BMPs identified in the above publications. Engineering professionals are encouraged to design innovative ways to address site specific conditions.
E. 
Sediment And Erosion Control Plan. Where natural vegetation is removed during grading operations, it shall be replaced as specified herein. The sediment and erosion control plan shall indicate the proposed phasing of the project to include conveyance systems, detention facilities, clearing, rough grading and construction, final grading, landscaping. When grading operations are substantially complete or have been suspended for fourteen (14) days, revegetation shall occur. Such revegetation shall meet the below criteria for either temporary or intermediate seeding.
F. 
Temporary Seeding. This is the establishment of fast-growing annual vegetation to provide economical erosion control for up to twelve (12) months and reduce the amount of sediment moving off the site. This practice applies when the landscape is anticipated to be disturbed within the next twelve (12) months. The required application rates are as follows: one (1) bushel of wheat or oats per acre; 10-20-10 fertilizer at four hundred (400) pounds per acre; eighty (80) to one hundred (100) bales of straw mulch per acre.
G. 
Intermediate Seeding. This is the establishment of perennial vegetation on disturbed areas for periods longer than twelve (12) months. This type of vegetation provides economical long-term erosion control and helps prevent sediment from leaving the site. The required application rates are the same as for temporary seeding with the addition of forty (40) to fifty (50) pounds per acre of fescue grass seed. The application of fescue is not required during the period of May 15 to August 15. However, it shall be applied as soon as weather conditions permit following August 15.
H. 
Off-Season Cover. Revegetation is still required in all seasons using alternative seed mixes better suited for growth in the summer and winter. Alternative stabilization methods may be explored such as erosion matting or mulch cover.
I. 
Reseeding. Reseeding shall occur at any time at the direction of the City Engineer if necessary to obtain the desired erosion control benefits. Vegetation types other than those specified herein may be utilized upon approval of the Engineer.
J. 
Minimum Requirements. The criteria established herein are the minimum requirements for erosion and sediment control. The owner may at any time establish permanent vegetation which exceeds these requirements.