(A) Applicability. All clearing, grading, stripping, excavating and filling which is subject to the permit requirements of this chapter shall be subject to the applicable standards and requirements set forth in this section. Development which is exempted from the permit requirements of this chapter are still required to take actions to control erosion and sedimentation leaving that development site, and that those actions shall be generally consistent with this section.
(B) Responsibility. The permittee shall not be relieved of responsibility for damage to persons or property otherwise imposed by law, and the city or its officers or agents will not be made liable for such damage, by:
(1) The issuance of a permit under this chapter;
(2) Compliance with the provisions of that permit or with conditions attached to it by the Director;
(3) Failure of city officials to observe or recognize hazardous or unsightly conditions;
(4) Failure of city officials to recommend denial of or to deny a permit; or
(5) Exemptions from the permit requirements of this chapter.
(C) Site design requirements.
(1) On-site sediment control measures, as specified by the following criteria, shall be constructed and functional prior to initiating clearing, grading, stripping, excavating or fill activities on the site.
(a) For disturbed areas draining less than one acre, filter barriers (including filter fences, straw bales or equivalent control measures) shall be constructed to control all off-site runoff as specified in referenced handbooks. Vegetated filter strips, with a minimum width of 25 feet, may be used as an alternative only where runoff in sheet flow is expected.
(b) For disturbed areas draining more than one, but less than five, acres, a sediment trap or equivalent control measure shall be constructed at the downslope point of the disturbed area.
(c) For disturbed areas draining more than five acres, a sediment basin or equivalent control measure shall be constructed at the downslope point of the disturbed area.
(d) Sediment basins and sediment traps designs shall provide for both detention storage and sediment storage. The detention storage shall be composed of equal volumes of “wet” detention storage and “dry” detention storage and each shall be sized for the two-year, 24-hour runoff from the site under maximum runoff conditions during construction. The release rate of the basin shall be that rate required to achieve minimum detention times of at least ten hours. The elevation of the outlet structure shall be placed such that it only drains the dry detention storage.
(e) 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 of sediment generated in one year. For construction periods exceeding one year, the one-year sediment load and a sediment removal schedule may be substituted.
(2) Storm water conveyance channels, including ditches, swales and diversions, and the outlets of all channels and pipes shall be designed and constructed to withstand the expected flow velocity from the ten-year frequency storm without erosion. All constructed or modified channels shall be stabilized within 48 hours, consistent with the following standards:
Design Flow Velocity (feet per second) | Lining Material |
Less than 3 | Seeded |
0 to 5 | Sod, staked |
0 to 7 | Erosion control blanket as approved by the City Engineer |
0 to 10 | Rip-rap |
0 to 15 | Grouted rip-rap |
Over 15 | Paved concrete or sound in-situ bedrock |
(3) Disturbed areas shall be stabilized with temporary or permanent measures within seven calendar days following the end of active disturbance, or redisturbance, consistent with the following criteria:
(a) Appropriate temporary or permanent stabilization measures shall include seeding, mulching, sodding and/or non-vegetative measures.
(b) Areas having slopes greater than 20% shall be stabilized with sod, mat or blanket in combination with seeding, or equivalent.
(4) Land disturbance activities in stream channels shall be avoided, where possible. If disturbance activities are unavoidable, the following requirements shall be met.
(a) 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.
(b) The time and area of disturbance of stream channels shall be kept to a minimum. The stream channel, including bed and banks, shall be restabilized within 48 hours after channel disturbance is completed, interrupted or stopped.
(c) Channel relocation should be avoided whenever possible. Whenever channel relocation is necessary, the new channel shall be constructed in the dry and fully stabilized before flow is diverted.
(5) Storm sewer inlets and culverts shall be protected by sediment traps or filter barriers meeting accepted design standards and specifications, but implemented in a manner which will avoid unacceptable flooding of pubic streets.
(6) Soil storage piles containing more than ten cubic yards of material shall not be located with a downslope drainage length of less than 25 feet to a roadway or drainage channel. Filter barriers, including straw bales, filter fence or equivalent, shall be installed immediately on the downslope side of the piles.
(7) 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.
(8) 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.
(9) All temporary and permanent erosion and sediment control practices must be maintained and repaired as needed to assure effective performance.
(10) All temporary erosion and sediment control measures shall be disposed of within 30 days after final site stabilization is achieved with permanent soil stabilization measures. Trapped sediment and other disturbed soils resulting from the disposition of temporary measures should be permanently stabilized to prevent further erosion and sedimentation.
(D) Maintenance of control measures.
(1) All soil erosion and sediment control measures necessary to meet the requirements of this chapter shall be maintained periodically by the applicant or subsequent land owner during the period of land disturbance and development of the site in a satisfactory manner to ensure adequate performance.
(2) Effective maintenance of control measures is critical to their success and shall be budgeted into the erosion and sediment control plan.
(3) Particular emphasis shall be placed on the following types of maintenance needs: repair and replacement of sediment barriers, such as straw bales; removal of excess accumulated sediment from traps, basins and channels; irrigation, fertilization or reseeding of vegetatively stabilized areas; repair of scour or gully development on slopes and in channels; removal of sediment from roadways; and control of dust.
(E) Inspection.
(1) (a) The Director, City Engineer or their designees shall make inspections as hereinafter required and shall either approve that portion of the work completed or shall notify the permittee wherein the work fails to comply with the site development or erosion and sedimentation control plan as approved. Plans for grading, stripping, excavating and filling work bearing the stamp of approval of the Director shall be maintained at the site during progress of the work.
(b) In order to obtain inspections and to ensure compliance with the approved erosion and sediment control plan, the site development or building permit and this chapter, the permittee shall notify the Director within two working days of the completion of the construction stages specified below:
1. Upon completion of installation of sediment and runoff control measures (including perimeter controls and diversions), prior to proceeding with any other earth disturbance or grading;
2. After stripping and clearing;
3. After rough grading;
4. After final grading;
5. After seeding and landscaping deadlines; and
6. After final stabilization and landscaping, prior to removal of sediment controls.
(2) (a) If stripping, clearing, grading and/or landscaping are to be done in phases or areas, the permittee shall give notice and request inspection at the completion of each of the above work stages in each phase or area.
(b) If an inspection is not made and notification of the results given within five working days after notice is received by the city from the permittee, the permittee may continue work at his or her own risk, without presuming acceptance by the city.
(c) Notification of the results of the inspection shall be given in writing at the site.
(F) Special precautions.
(1) (a) If at any stage of the grading of any development site the Director determines by inspection that the nature of the site is such that further work authorized by an existing permit is likely to imperil any property, public way, stream, lake, wetland or drainage structure, the Director or City Engineer may require, as a condition of allowing the work to be done, that such reasonable special precautions to be taken as is considered advisable to avoid the likelihood of such peril.
(b) “Special precautions” may include, but shall not be limited to, a more level exposed slope, construction of additional drainage facilities, berms, terracing, compaction, or cribbing, installation of plant materials for erosion control and recommendations of a registered soils engineer and/or engineering geologist which may be made requirements for further work.
(2) (a) Where it appears that storm damage may result because the grading on any development site is not complete, work may be stopped and the permittee required to install temporary structures or take such other measures as may be required to protect adjoining property or the public safety.
(b) On large developments or where unusual site conditions prevail, the Director may specify the time of starting grading and time of completion or may require that the operations be conducted in specific stages so as to ensure completion of protective measures or devices prior to the advent of seasonal rains.
(G) Amendment of plans.
(1) Major amendments of the site development or erosion and sedimentation control plans shall be submitted to the Director or City Engineer and shall be processed and approved or disapproved in the same manner as the original plans.
(2) Field modifications of a minor nature may be authorized by the Director by written authorization to the permittee.
(Ord. 3319, passed 2-22-2005)