A. General: A properly designed storm water management system shall be installed, consisting of pipes, manholes, inlets, and other necessary drainage structures, appurtenances, ditches, swales, detention/retention facilities, etc., that will adequately drain and manage storm water from the subdivision and/or development. All storm water management system components shall meet the requirements of the Kane County storm water management ordinance as adopted per ordinance 01-36, June 18, 2001, and any revisions made thereto.
B. Storm Sewer System: The storm sewer system shall be designed to intercept and convey the storm water runoff resulting from a design rainfall event that has a statistical probability of occurring once every ten (10) years as defined using the Illinois state water survey publication entitled "Frequency Distributions And Hydroclimatic Characteristics Of Heavy Rainstorms In Illinois", bulletin 70, or any official update issued thereto. The storm sewer system shall be designed for gravity flow conditions without surcharging at any point within the system. Design flow velocities shall be a minimum of 2.5 feet per second and a maximum of ten feet (10') per second. Storm sewers shall be designed using the procedures found in chapter 8 of the IDOT drainage manual.
The minimum pipe size in any storm sewer system shall be twelve inches (12") in diameter. All storm sewer pipe shall be reinforced concrete pipe (RCP), with a minimum class IV strength rating as defined using the most current version of ASTM specification C76 unless otherwise approved by the city engineer. The minimum depth of cover over the top of the pipe shall be thirty inches (30") unless site conditions prevent it and the city engineer or his/her authorized representative approves a lesser depth.
Storm sewer structures will be permitted in the back yards of residential areas only to the minimum extent needed to effectively drain these areas as determined by the city engineer or his/her authorized representative. Storm sewer mains will not be allowed in rear yard easements. Storm sewer structures in back yards must be connected directly to storm sewer mains in the city right of way using lateral sewers in side yard easements. All storm sewer pipes within side yard easements shall have gasketed joints in accordance with ASTM specification C-361-03a.
C. Sump Pump Drainage: A sump pump junction box, a minimum of twenty four inches (24") in diameter by thirty inches (30") deep, shall be provided for each lot or pair of lots and generally located in the parkway centered on the side lot line. The sump pump junction box shall have an east Jordan number 1020 type M1 frame and lid, or approved equal, at finished grade.
House or building sump pump services shall be a minimum four inch (4") diameter pipe and shall be connected to the junction box.
Where properly located, curb and yard inlets may be used in lieu of a sump pump junction box.
D. Storm Sewer Structures: Storm sewer structures consist of inlets, storm manholes, catch basins, and sump pump junction boxes. Inlets shall be a minimum twenty four inch (24") diameter precast concrete type A inlets as shown on the current city of Batavia engineering department standard construction detail drawings. Storm manholes and catch basins shall be sized, located and constructed in accordance with the referenced city construction details. Inlet and manhole structures shall have a poured concrete invert or slope, finished in accordance with the city construction details, to prevent standing water in these structures. The most downstream structure in every development shall be a catch basin fitted with a grit/oil separation device as shown on the city construction details. Additional catch basins with grit/oil separators within the development may be required as directed by the city engineer or his/her authorized representative. Two (2) inlets or catch basins shall be provided on each side of the road at all sag locations.
The maximum spacing of inlets shall be four hundred feet (400') unless otherwise directed by the city engineer or his/her authorized representative.
Frames and grates for storm sewer structures shall be as follows or approved equal:
Inlets or catch basins in the curb line | East Jordan number 7220, type 1 curb back, type M1 grate |
Structures in ditches or detention/retention facilities | East Jordan number 6527 |
Yard inlets | East Jordan number 1020, type M1 grate |
Manholes | East Jordan number 1020, type M1 or type A |
Sump pump junction box | East Jordan number 1020, type M1 or type A grate as appropriate |
E. Subdrainage: In areas with poorly drained soils and/or a high water table, perforated pipe subdrains, six inch (6") minimum diameter, will be required as directed by the city engineer or his/her authorized representative. Subdrains shall be designed in accordance with the most current IDOT procedures and requirements. The subdrain trench shall be lined with the appropriate geotextile fabric. The pipe shall have two (2) rows of perforations and shall be laid with the perforations down. The trench shall be backfilled with crushed rock, IDOT class CA-7 or approved equal to the top of subgrade elevation with geotextile folded over the top of the backfill. The minimum depth of cover over the top of the subdrain pipe shall be eighteen inches (18") unless site conditions prevent it and the city engineer or his/her authorized representative approves a lesser depth. The minimum trench width shall be eighteen inches (18"). Subdrains will be provided at all roadway sag locations.
F. Pipe Materials:
Storm sewer | Reinforced concrete pipe ASTM C76 class IV minimum |
Sump pump lines | PVC pipe with a maximum SDR of 26 ASTM D-3034 |
Subdrainage | PVC perforated pipe with a minimum SDR of 35, 2 rows of perforations; pipe shall meet ASTM D-3034 requirements |
Culverts | Reinforced concrete pipe ASTM C76 class IV minimum with precast concrete flared end sections on each end of the culvert. The minimum culvert size is 12 inch diameter. All culverts shall have the appropriate grating conforming to current city standards and specifications. The minimum depth of cover over the top of the culvert pipe shall be 12 inches. |
Alternate materials may be considered. | |
G. Yard Drainage: Positive rear and side yard drainage shall be required in all developments. Side slopes on swales, ditches, berms, and storm water detention/retention facilities shall not exceed 4:1. Minimum as built swale grades shall be two percent (2%). Swale drainage shall be picked up with inlets prior to reaching street right of way and conveyed by pipe into the storm sewer system. Yard drainage plans shall be part of the site grading plans.
H. Storm Water Detention/Retention: Provided in accordance with the requirements of the Kane County storm water management ordinance, as adopted by ordinance 01-36, June 18, 2001, and any revisions made thereto. Earthen detention/retention basins and ponds shall be provided in a separate lot and covered with a storm water and/or conservation easement acceptable to the city. These detention/retention facilities will not be permitted in easements on private property residential lots.
Underground detention/retention facilities will be permitted only if it can be demonstrated that there is no practical alternative that would allow a surface facility to be constructed. The owner of an underground detention/retention facility shall have a qualified engineer, licensed in the state of Illinois, inspect the facility annually and subsequently submit a signed and sealed inspection report to the city engineer. The report shall include any operational and maintenance deficiencies with the facility. If identified, the owner shall append the inspection report with a signed letter that provides a plan and schedule for correcting such deficiencies. Once any deficiencies are corrected, a final signed and sealed inspection report shall be submitted to the city engineer that includes a certification statement that the underground detention/retention facility is operating in full conformance with the original design intent and parameters.
Retaining walls will be permitted for detention/retention facilities only if it can be demonstrated that there is no practical alternative that would allow the detention/retention facility to be constructed without such walls. Where permitted, these retaining walls shall not exceed three feet (3') in height. If retaining walls greater than three feet (3') are required, the wall must be terraced after the first three foot (3') lift. A horizontal space of not less than five feet (5') will be required between wall lifts. Portland cement concrete walls of any height shall be designed and sealed by a registered professional structural engineer licensed in the state of Illinois. Modular block retaining walls shall be designed and constructed in accordance with the manufacturer's specifications. The appropriate individual(s) licensed and/or certified in the state of Illinois shall provide engineering seals and certifications for modular block wall designs in accordance with the manufacturer's requirements.
I. Specifications: All storm sewer system construction work shall be done in accordance with applicable sections of the "Standard Specifications For Sewer And Water Main Construction In Illinois", latest edition, with any special provisions specified, and in accordance with current city standards and specifications. (Ord. 04-72, 12-20-2004)