(A) Objective. It is the objective of this chapter to control soil erosion and sedimentation resulting from development activities in the city. Measures taken to control erosion and sedimentation should be adequate to assure that sediment is not transported from the site by storm events of a ten year frequency, or less. The following principles shall apply to all development activities within the city; and division (B)(9) below shall apply to all sites at all times, regardless of whether development activities are being performed on the site.
(B) General design principles.
(1) Site development should be planned so that it is consistent with and conforms to the topography and soils of the site so as to prevent and minimize soil erosion. Radical cuts and fills should be avoided in areas of steep slopes. Natural contours should be maintained as much as possible.
(2) Natural vegetation should be retained and protected wherever possible. Areas immediately adjacent to natural watercourses shall be left undisturbed wherever possible to form a buffer to keep soil on the site. At a minimum, the undisturbed areas of natural vegetation shall be at least twenty-five feet wide.
(3) The area of land exposed during site development should be limited to the smallest working area practicable. The period of time during which land is exposed without vegetation should be limited to the shortest period practicable and should be during periods of the least intense rainfall. Stripping and excavation should be minimized. Vegetative cover should be restored at the earliest possible time. Large topsoil stockpiles and land removal of topsoil should be minimized. Topsoil stockpiles should be revegetated during periods of extended use.
(4) For channelized or concentrated flows, sediment basins, debris basins, desilting basins, or silt traps should be installed and maintained to remove sediment from run-off waters from land undergoing development. To remove sediment from sheet flow run-off, silt fence, filter fence, or vegetative filter strips should be used. These control devices shall be installed prior to work starting in the development and shall remain in place until vegetative cover is re-established permanently, and all other permanent control devices are installed and functioning.
(5) The selection of erosion and sedimentation control measures should be based on the probable frequency of climatic and other events likely to contribute to erosion, and on evaluation of the risks, costs, and benefits involved.
(6) Aesthetics, public health and the requirements of continuing maintenance should be considered in the design and implementation of erosion control facilities and practices as part of an erosion and sedimentation control plan.
(7) Provision should be made to accommodate the increased water run-off caused by changed soil and surface conditions both during and after development. Drainage ways should be designed and constructed so that their final gradients and the resultant velocities of water will not create additional erosion on site or beyond the project limits.
(8) Permanent vegetation and hydraulic structures should be established and installed as soon as practicable during development.
(9) Measures shall be taken to prevent tracking of mud and sediment onto public ways. This shall include, as a minimum, a means of vehicular egress from the site that has installed therein a rock driving surface, underlain with filter fabric, which extends back on to the development site at least 30 feet from the paved road surface on a single residence lot, and 70 feet from the paved road surface for all other developments. The rock composing this means of egress shall be IDOT coarse aggregate gradations CA-1 or CA-2. This rock surface shall be replenished and maintained so that it serves the purpose for which it is intended throughout the period of development. Any mud or sediment that does get deposited on a public way via vehicle or other means, shall be removed within two hours so as to prevent any accumulation.
(C) Erosion and sedimentation control plans. All commercial, industrial, residential, and planned development projects shall have erosion and sedimentation control plans prepared and submitted to the city for review prior to commencing. Said plans shall show:
(1) Existing topography of the site and adjacent land within 100 feet of the boundaries, drawn at no greater than one foot contour intervals and clearly portraying the topography and drainage pattern of the area.
(2) The location of existing buildings, temporary structures, utilities, water bodies, flood plains, hydraulic structures, paved areas and other significant natural or man-made features on the site and adjacent land within 100 feet of the boundary.
(3) Proposed use of the site, including present development and planned development and utilization; areas of excavation, grading, and filling; proposed contours, finished grades, and street profiles; provisions for storm drainage, including the control of accelerated erosion, with a drainage area map and computations; kinds and locations of utilities; and areas and acreages proposed to be paved, covered, sodded or seeded, vegetatively stabilized, or left undisturbed.
(4) All erosion and sedimentation control devices, structures or measures necessary to comply with the general principles of this chapter and the standards set forth herein. The erosion and sedimentation control plan shall show all such devices, structures or measures to be employed temporarily during development of the parcel and to be employed permanently upon completion of development. These measures shall be shown on the detailed grading plan.
(5) Provisions for maintenance of erosion and sedimentation control devices, structures or measures.
(6) Identification of the person(s) who will have responsibility for maintenance of erosion and sedimentation control devices, structures and measures, during and after development is completed.
(7) As a minimum measure, staked hay bales or acceptable alternatives shall be properly placed around the frames of all open lid structures, e.g. storm sewer inlets, during construction to prevent sediment from clogging sewers and ditches and polluting or silting drainage facilities, watercourses or bodies of water. Where needed to reduce erosion and sediment movement from sheet flow, silt filter fence or vegetative filter strips shall be used.
(D) Special precautions. If at any stage of development, the City Engineer determines that the nature of the site, parcel or lot is such that further work already authorized may cause harm or accelerated erosion to any property, public way, watercourse, drainageway, hydraulic structure or other structure, the City Engineer may require that such reasonable special precautions be taken as are necessary or appropriate to avoid such harm or accelerated erosion. "Special precautions" may include, but are not limited to, one or more of the following requirements: a more level exposed slope, construction of additional drainage structures, berms, terracing, compaction, cribbing, installation of plant materials for erosion control, other temporary structures, implementation of recommendations of a soils engineer and/or engineering geologist, or completion of work in stages so as to insure completion of protective measures or devices by specified dates.
(E) Upon finding by the City Engineer that the plans submitted are in compliance with this chapter, work directly covered by the plans may commence as approved.
(Ord. 3270, passed 8-28-00)