(a) Erosion and Sediment Kept on Site. Erosion and sedimentation caused by accelerated wind or storm water runoff over the site due to earth disturbing activities shall be stabilized and confined to be within the boundaries of the development site to the maximum extent practicable.
(b) Discharge of Untreated Stormwater. To the maximum extent practicable, the site shall not discharge untreated stormwater directly into a receiving body of water during or after construction activities.
(c) Structural and Nonstructural Best Management Practices.
(1) Nonstructural stormwater management practices shall be used to the maximum extent practicable. Such practices may include, but not be limited to, preserving riparian areas, preserving existing vegetation and vegetative buffer strips, phasing of construction, and designation of tree preservation areas;
(2) Nonstructural and structural stormwater management practices shall be designed in accordance with requirements and standards specified in this chapter and/or by the authorized agent(s);
(3) Structural storm water management practices shall be placed in easements and recorded on the property deeds on which they are located and shall remain unaltered unless first approved by the City Engineer;
(4) Structural stormwater management practices shall be designed to treat a water quality volume calculated for the site based on a three-quarter (0.75) inch rainfall (first flush) and designed to outlet over a designated draw- down time per type of structural storm water management practice; and
(5) The water quality volume structural stormwater management practices should be considered in the design of storm water detention, retention and infiltration facilities to the maximum extent practicable.
(d) Stream and Wetland Riparian Buffers. The site owner and/or applicant shall leave an undisturbed riparian buffer on both sides of and/or surrounding water resources, except for crossings and other riparian area and wetland impacts approved by the City Engineer and all other authorities having jurisdiction, if applicable. Buffer width will be determined using criteria established in the City of Carlisle Zoning Ordinance. The City Engineer may increase the widths required based upon floodplain, topography, vegetative cover, canopy cover, and soil types, etc. if deemed necessary.
(e) Channel Protection. To protect stream channels from degradation a specific channel protection criteria shall be provided as prescribed in the latest edition of Rainwater and Land Development, ODOT Location and Design Manual and as determined by the City Engineer.
(f) Temporary Stabilization of Disturbed Areas and Soil Stockpiles, Sediment Control Structures. See Appendix A, Earth Disturbing Activity Performance Standards, attached to Ordinance No. 30-08, passed November 11, 2008, for detail.
(g) Protection of Adjacent Properties/Public Rights-of-Way. Properties, public rights-of-way, and thoroughfares within the City adjacent to the site of an earth disturbing activity, either within or outside the City, shall be protected from sediment deposition at all times. This may be accomplished by preserving a well-vegetated buffer at the perimeter of the site, by installing perimeter controls such as sediment barriers, filters, dikes, sediment basins, or by a combination of such measures. If said measures fail during the course of construction activities, the owner/developer shall cease all work and restore said measures to good working order within
seven days.
(h) Stabilization of Waterways and Outlets. All on-site stormwater conveyance channels shall be designed and constructed to withstand the expected velocity of flow without erosion. Permanent methods adequate to prevent erosion shall also be provided at the outlets of all pipes and drainage channels. All storm conveyance channels shall be designed in accordance with the following criteria:
(1) Major waterways: The channel shall be designed for the 100 year storm;
(2) Secondary waterways: The channel shall be designed for the fifty year storm;
(3) Minor waterways: The channel shall be designed for the twenty-five year storm; and
(4) All storm conveyance channels shall be designed to protect all structures from the 100 year storm.
(i) Storm Sewer Inlet Protection. All storm sewer inlets shall be protected so that sediment-laden water will not enter the conveyance system without first being filtered or otherwise treated to remove sediment. All inlet protection devices shall be inspected, maintained and repaired weekly and after all major storm events by the owner/developer as needed to ensure proper working order throughout the course of construction activities.
(j) Working in or Crossing Watercourses.
(1) All activities shall be kept out of watercourses to the maximum extent possible. Where in-channel work is necessary, precautions shall be taken to stabilize the work area during construction to minimize erosion. The channel (including bed and banks) shall be restored to its original cross- section and all disturbed areas stabilized immediately after in-channel work is completed; and
(2) Where a watercourse will be crossed regularly during construction, a temporary stream crossing shall be provided by using clean materials meeting the requirements of the City Engineer and the U.S. Army Corps of Engineers, used for the shortest period practical, removed following site construction, and restored as described in subsection (j)(1) above.
(k) Maintenance and Removal of Temporary Measures.
(1) All temporary erosion and sediment control practices shall be maintained and repaired to assure continued performance; and
(2) All temporary erosion and sediment control measures shall be removed within thirty days after final site stabilization is achieved or after the temporary measures are no longer needed. Trapped sediment and other disturbed soil areas resulting from the removal of temporary measures shall have the final grade re-established and be permanently stabilized to prevent further erosion and sedimentation.
(l) Maintenance of Permanent Measures. All permanent erosion and sediment control practices shall be maintained and repaired to ensure continual performance, inspected to ensure proper installation and long term functionality. If a defect is found, the control measure shall be repaired or replaced as deemed by City officials and/or its authorized agent(s) within seven days after final site stabilization is achieved.
(m) Control of Construction Site Debris and Wastes. All owners, applicants, contractors and developers shall control and remove wastes such as discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste on construction sites and shall keep streets and gutters clear of all sediment and debris from the site throughout the duration of construction activities.
(1) Use, safety, and maintenance of stormwater practices.
A. Stormwater management practices shall be designed for the ultimate permanent use of the site and function safely and with minimal maintenance; and
B. If an inspection reveals that a control practice is in need of repair or maintenance, with the exception of a sediment settling pond, it must be repaired or maintained within seven days of the inspection or notification to the owner, whichever is later. Sediment settling ponds must be repaired or maintained within fourteen days of the inspection or notification to the owner, whichever is later. If additional time is needed to complete the stormwater management practice repairs, an alternate time frame may be agreed to by the City upon written request from the applicant.
(2) Inspection of stormwater controls. (See subsection (c) hereof for specific requirements.)
A. All controls on the site shall be inspected at least once every seven calendar days and within twenty-four hours after any storm event greater than three-quarters of an inch (0.75) of rain per twenty-four hour period;
B. The site owner and/or applicant shall assign inspection personnel experienced in the installation and maintenance of erosion and runoff controls to conduct these inspections to ensure that all stormwater control practices are functional, that all provisions of the SMP and this regulation are being met, and whether additional control measures are required;
C. On- and off-site discharge locations shall be inspected to ascertain whether erosion and sediment control measures are effective in preventing significant impacts to the receiving waters; and
D. Detailed records of inspections of the stormwater controls and overall erosions condition of the site shall be maintained for up to three years following the final stabilization of the site.
(n) Accessibility and Easements. (See Section 1454.08(f) for specific requirements.) All permanent storm water management measures shall have easements sufficient to cover the facility and to provide access for inspection and maintenance.
(o) Status of Standards. The standards identified in this section are general guidelines. Each application shall be reviewed on a case by case basis and some may require additional and more stringent requirements, while others may have individual requirements waived by the authorized agent.
(p) Complaints. The City or its authorized agent(s) shall investigate any complaint related to earth disturbing activities covered by this chapter.
(Ord. 30-08. Passed 11-11-08.)