§ 164.024 STORMWATER REQUIREMENTS FOR AGRICULTURAL LAND USE INCLUDING CROPLANDS, PASTURE LANDS AND FARMSTEADS.
   (A)   Applicability. Regulations under this section apply only to croplands, pasturelands, farmsteads and outbuildings associated with those agricultural practices. Compliance with the requirements of this section shall be construed as compliance with the stormwater ordinance for the above land uses and no further regulation under the ordinance will apply. Any other land use, including, but not limited to, greenhouses, nurseries, container grown plants, equestrian facilities, the sale of agricultural products to the public or any other commercial activities involving the new construction of gravel or paved parking facilities or buildings, where the aggregate area of proposed impervious surfaces is 25,000 square feet or more are required to comply with all applicable sections of this chapter.
   (B)   Conservation planning and performance standards.
      (1)   To comply with this section, landowners shall practice conservation planning whose product shall be a management system, which addresses site runoff, soil erosion and sediment control, surface and subsurface drainage. Any acreage with a signed and approved NRCS Conservation Plan is exempt from the requirements of this section and the chapter.
      (2)   Applicable approved practices include:
         (a)   Vegetated grass waterways;
         (b)   Contour buffer strips;
         (c)   Critical area planting and cover crops;
         (d)   Terrace ridges and diversions;
         (e)   Contour strip cropping;
         (f)   Contour farming;
         (g)   Conservation crop rotation;
         (h)   Conservation tillage and crop residue management; and
         (i)   Other standard practices for conservation planning in accordance with the NRCS Field Office Technical Guide (current edition) or as otherwise approved by the County NRCS District Conservationist.
      (3)   The performance standard for conservation planning and implementation shall be a management system which will develop a set of field practices which will reduce the calculated actual soil loss to the “tolerable soil loss” (T) as calculated by the revised Universal Soil Loss Equation for the actual site conditions. Cropland tillage and resource management methods shall be consistent with the Technical Guide Notice IL-108 and shall be considered evidence of compliance with the “T” performance standard.
   (C)   Drainage practices, requirements and design criteria.
      (1)   Drainage for agricultural purposes shall be consistent with those practices identified as appropriate for good husbandry given the soil types, slopes and crops. An agricultural drainage system may consist of both subsurface drainage systems and surface drainage systems. Where active drainage districts maintain drainage systems, they shall be consulted on surface and subsurface drainage within the district boundaries.
      (2)   Requirements applying to subsurface and surface drainage system shall be as follows.
         (a)   Agricultural subsurface drainage systems. Drain tile systems shall be maintained and constructed in accordance with subsurface drainage recommendations for the appropriate soil drainage group as specified by the University of Illinois Extension Service Drainage Guide link http://urbanext.illinois.edu/lcr/drainage.cfm. Surface inlets into the subsurface drainage system shall be allowed where their use cannot be practicably avoided due to topography. They shall be installed using flow controls such as orifices and perforated risers with gravel filters and /or vegetative filters. In cases where the installation of the surface inlet is for the purpose of enhancing the drainage of farmed wetlands, the individual shall consult with the County NRCS District Conservationist.
         (b)   Surface drainage systems. Surface drainage systems shall be maintained and constructed in accordance with surface drainage recommendations for the appropriate soil drainage group as specified by the University of Illinois Extension Service link http://urbanext.illinois.edu/lcr//drainage.cfm . Surface drainage systems shall be built with geotechnically stable slopes and the surface when applicable shall be further stabilized utilizing the establishment of cool and warm season grass mixes as identified in Field Office Technical Guide (Illinois 108).
         (c)   Buffer strips. Open channels with a definable bed and banks shall use buffer strips having a minimum width of 25 feet in order to reduce the amount of erosion occurring from the conveyed flows as well as to help filter the runoff from the site into the waterway.
         (d)   Agricultural drainage systems. Agricultural drainage systems shall also comply with all regulations regarding wetlands as enforced by federal, state and local agencies.
   (D)   Sediment control for open channels.
      (1)   All open channel drainage systems shall maintain practices adjacent to the open outlet channel that will reduce the transportation of sediment off-site. Runoff from agricultural fields must pass through a sediment control system prior to discharge into the open channel conveyance system.
      (2)   Approved sediment control systems may consist of the following:
         (a)   Vegetated buffer shall have a minimum width of 25 feet planted with permanent grasses appropriate for soil stabilization and filtering;
         (b)   Grade control structures for over fall stabilization;
         (c)   Sediment traps adjacent to the stream channel; and
         (d)   Other standard practices for conservation planning in accordance with the NRCS Field Office Technical Guide (current edition) or as otherwise approved by the County NRCS District Conservationist or the Administrator.
   (E)   Maintenance and construction of drainage systems. Agricultural drainage systems shall be maintained so as to convey the expected flows for good drainage practices. The existing agricultural surface drainage systems shall not be enlarged unless the enlargement is consistent with all other divisions of this section. Maintenance and construction of subsurface drainage systems will not be subject to the requirements of other sections of this chapter except as they are regulated by other agencies. Maintenance projects by legally functioning drainage districts on existing agricultural drainage systems will not be subject to further permitting requirements under this chapter except as they relate to the jurisdiction of other agencies.
(Ord. 10-164, passed 6-17-2010)