On site sediment control measures, as specified by the following criteria, shall be constructed as specified in the referenced handbooks, and functional prior to initiating clearing, grading, stripping, excavating, or fill activities on the site:
(A) For new developments or redevelopments of more than one acre but less than five acres, a sediment trap or equivalent control measure shall be constructed at the downslope point of the disturbed area;
(B) For new developments or redevelopments of one acre or greater than five acres, a sediment basin or equivalent control measure shall be constructed at the downslope point of the disturbed area;
(C) Sediment basin and sediment trap designs shall provide for both dry detention and wet detention sediment storage. The detention storage shall be composed of equal volumes of wet detention storage and dry detention storage and each shall be sized as regulated in this chapter. The release rate of the basin shall be that rate as regulated in this chapter. The elevation of the outlet structure shall be placed such that it only drains the dry detention storage;
(D) The sediment storage shall be sized to store the estimated sediment load generated from the site over the duration of the construction period with a minimum storage equivalent to the volume or sediment generated in one year. For construction periods exceeding one year, the one-year sediment load and a sediment removal schedule may be substituted;
(E) (1) To the extent possible or as otherwise regulated in this chapter, all desirable trees eight inches in diameter and larger shall be protected for their present and future value for erosion protection and other environmental benefits.
(2) Trees that have been selected for preservation shall be protected following criteria from Illinois Urban Manual prior to the beginning of any clearing, grading, stripping, excavation, or filling of the site. A “No Construction Zone” shall be established and marked at the perimeter of the drip line of each tree which is to be preserved;
(F) Stormwater conveyance channels, including ditches, swales, and diversions, and the outlets of all channels and pipes shall be designed and constructed as regulated in this chapter. All constructed or modified channels shall be stabilized within 48 hours, consistent with the following standards and as required in the referenced handbooks:
(1) For grades up to 4%, seeding in combination with mulch, erosion blanket, or an equivalent control measure shall be applied. Sod or erosion blanket or mat shall be applied to the bottom of the channel;
(2) For grades of 4% to 8%, sod or an equivalent control measure shall be applied in the channel; and
(3) For grades greater than 8%, rock, riprap, or an equivalent control measure shall be applied over filter fabric or other type of soil protection, or the grade shall be effectively reduced using drop structures.
(G) Land disturbance activities in stream channels shall be avoided, where possible, or as regulated by this chapter. If disturbance activities are unavoidable, the following requirements shall be met:
(1) Construction vehicles shall be kept out of the stream channel to the maximum extent practicable. Where construction crossings are necessary, temporary crossings shall be constructed of non-erosive material, such as riprap or gravel;
(2) The time and area of disturbance of stream channels shall be kept to a minimum. The stream channel, including bed and banks, shall be stabilized within 48 hours after channel disturbance is completed, interrupted, or stopped; and
(3) Whenever channel relocation is necessary, the new channel shall be constructed under dry conditions and fully stabilized before flow is diverted, incorporating meanders, pool and riffle sequence, and riparian planting.
(H) Storm sewer inlets and culverts shall be protected by sediment traps or filter barriers meeting accepted design standards and specifications;
(I) Soil storage piles containing more than ten cubic yards of material shall not be located with a downslope drainage length of less than 50 feet to a roadway, drainage channel, or abandoned mine. Filter barriers, including straw bales, filter fence, or equivalent, shall be installed immediately surrounding the perimeter of the pile;
(J) If dewatering devices are used, discharge locations shall be protected from erosion. All pumped discharges shall be routed through appropriately designed sediment traps or basins, or equivalent, and shall not be deposited into an abandoned mine;
(K) Each site shall have graveled (or equivalent) entrance roads, access drives, and parking areas of sufficient length and width to prevent sediment from being tracked onto public or private roadways. Any sediment reaching a public or private road shall be removed by shoveling or street cleaning (not flushing) before the end of each workday and transported to a controlled sediment disposal area.
(Ord. passed - -)