1049.01 Purpose.
1049.02 Definitions.
1049.03 Scope.
1049.04 Site development plan.
1049.05 Performance standards.
1049.06 Storm water management plan requirements.
1049.07 Inspections and maintenance.
1049.08 Compliance responsibility.
CROSS REFERENCES
Management and control of sewerage system - see Ohio R.C. 729.50
Regulations to control house sewers and connections - see Ohio R.C. 799.01
Storm water prohibited in sanitary sewer - see S.U. & P. S. 1042.26, 1046.06
Removal of debris from sewer - see S.U. & P.S. 1046.28
Storm sewer connections and regulations - see S.U. & P.S. Ch. 1048
Storm sewers in subdivisions - see P. & Z. 1228.06
Grading to provide for water disposal - see B. & H. 1472.01
(a) The City has determined that the lands and waters of the City are limited resources and that their quality is of primary importance in promoting and maintaining the health, safety, and general well-being of all life within its jurisdictional boundaries. The purpose of this chapter is to provide for the protection of surface and ground waters from contamination from urban storm water runoff as related to construction and development activities and post-construction storm water management and to protect the land and water resources of the City by establishing standards to achieve a level of soil erosion and storm water control that will minimize and abate degradation of land and water resources and damage to public and private property resulting from earth disturbing activities.
(b) The objectives of this chapter are:
(1) To assure that those involved in earth-disturbing activities minimize both soil erosion and the volume and rate of storm water runoff from their sites;
(2) Preserve to the extent practicable the natural drainage characteristics of the site and minimize the need to construct, repair, and replace enclosed, subsurface storm drain systems;
(3) Assure that storm water controls are incorporated into site planning and design at the earliest possible stage and that all storm water management practices are properly designed, constructed, and maintained;
(4) Prevent unnecessary stripping of vegetation and loss of soil and to promptly re- vegetate and stabilize the site following earth disturbing activities;
(5) Reduce the need for costly maintenance and repairs to roads, embankments, ditches, water resources, wetlands, and storm water management practices;
(6) Encourage the construction of storm water management practices that serve multiple purposes such as flood control, erosion control, fire protection, water quality protection, recreation, and habitat preservation;
(7) Preserve to the maximum extent practicable natural infiltration and groundwater recharge;
(8) To establish standards, principles, and procedures for the regulation of construction and development related earth disturbing activities that cause or may cause adverse water resource impacts resulting from storm water runoff and soil erosion;
(9) To provide homebuilders, developers, and landowners with consistent, technically feasible, and economically reasonable standards for erosion control and storm water management to promote the public health and safety and sound economic development in the City and throughout the Great Miami Watershed;
(10) To partially fulfill the City's responsibility as a local designated management agency to implement non-point source control activities set forth by the Miami Valley Regional Planning Commission (MVRPC) and authorized under Section 208 of the Federal Water Pollution Control Act (P.L. 92-500, 86 Stat. 816), 33 USC 1288, as amended by the Clean Water Act of 1977 (P.L. 95-217, 91 Stat. 156);
(11) To comply with 40 C.F.R. Parts 9, 122, 123, and 124, referred to as NPDES Storm Water Phase II, and Ohio EPA's Phase II Storm Water Program which require designated communities, including the City to develop a storm water management program to address the quality of storm water runoff during and after earth disturbing activities; and,
(12) In accordance with Article XVIII, Section 3 of the Ohio Constitution which grants municipalities the legal authority to adopt rules to abate soil erosion and water pollution by soil sediments and Ohio R.C. Chapter 1511 which grants municipalities the legal authority to adopt sediment and erosion control practices.
(Ord. 5973. Passed 2-20-07.)
For the purposes of this chapter, all words used in this chapter shall have their customary meanings as defined in Webster's New World Dictionary and/or Rainwater and Land Development, except those specifically defined in this section.
(a) “Accelerated erosion” means erosion caused by development activities that exceeds the natural processes by which the surface of the land is worn away by the action of water, wind, or chemical action.
(b) “Applicant” means a property owner or agent of a property owner who has filed an application for a storm water management permit.
(c) “Approval authority” means an official, organization, or group designated to review and approve/disapprove site development plans, storm water pollution prevention plans, storm water management plans.
(d) “Authorized agent” means an official (typically the City Engineer), organization, or group designated by the City Manager to provide technical guidance in the development and implementation of site development, storm water pollution prevention plans and storm water management plans, to review and approve/ disapprove such plans as authorized, and to enforce this chapter.
(e) “Best management practices (BMPs)” are schedules of activities, prohibitions of practices, general good house keeping practices, pollution prevention and educational practices, maintenance procedures, and other management practices to prevent or reduce the discharge of pollutants directly or indirectly to storm water, receiving waters, or the municipal separate storm sewer system. BMPs also include treatment practices, operating procedures, and practices to control site runoff, spillage or leaks, sludge or waste disposal, or drainage from materials storage.
(f) “Buffer” means a designated transition area around water resources or wetlands that is left in a natural, usually vegetated, state so as to protect the water resources or wetlands from runoff pollution. Construction activities in this area are restricted or prohibited.
(g) “Building” means any structure, either temporary or permanent, having walls and a roof, designed for the shelter of any person, animal, or property, and occupying more than 100 square feet of area.
(h) “Channel” means a natural or artificial watercourse with a definite bed and banks that conducts continuously or periodically flowing water.
(i) “City” means the City of Miamisburg.
(j) “Critical storm” means a storm which is calculated by means of the percentage increase in volume of runoff by a proposed earth disturbing activity or development area. The critical storm is used to calculate the maximum allowable storm water discharge rate from a site.
(k) “Cut” means an excavation. The difference between a point on the original grade and a designated point of lower elevation on the final grade.
(l) “Dedication” means the deliberate appropriation of property by its owner for general public use.
(m) “Detention basin” means an impoundment area created by constructing an embankment, excavating a pit, or both, for the purpose of temporarily storing storm water.
(n) “Detention facility” means a detention basin or alternative structure designed to temporarily store storm water runoff and gradually release the stored water at a controlled rate.
(o) “Developer” means a person who undertakes land disturbance activities.
(p) “Development area” means any contiguous area owned by one person or operated as one development unit included within the scope of these regulations, upon which earth-disturbing activities are planned or underway.
(q) “Drainage easement” means a legal right granted by a landowner to a grantee allowing the use of private land for storm water management purposes.
(r) “Earth-disturbing activity” means any grading, excavation, filling, or other alteration of the earth's surface where natural or man-made ground cover is destroyed.
(s) “Fill” means any act by which earth, sand, gravel, rock or any other material is placed, pushed, dumped, pulled, transported or moved to a new location above the natural surface of the ground or on top of the stripped surface and shall include the resulting grade conditions. The difference in elevation between a point on the original ground and a designated point of higher elevation on the final grade.
(t) “Hotspot” means an area where land use or activities generate highly contaminated runoff, with concentrations of pollutants in excess of those typically found in storm water.
(u) “Hydrologic Soil Group (HSG)” means a Natural Resource Conservation Service classification system in which soils are categorized into four runoff potential groups. The groups range from A soils, with high permeability and little runoff production, to D soils, which have low permeability rates and produce much more runoff.
(v) “Impervious cover” means those surfaces that cannot effectively infiltrate rainfall (e.g., building rooftops, pavement, sidewalks, driveways, etc).
(w) “Industrial storm water permit” means a National Pollutant Discharge Elimination System permit issued to a commercial industry or group of industries which regulates the pollutant levels associated with industrial storm water discharges or specifies on- site pollution control strategies.
(x) “Infiltration” means the process of percolating storm water into the subsoil.
(y) “Infiltration facility” means any structure or device designed to infiltrate retained water to the subsurface. These facilities may be above grade or below grade.
(z) “Jurisdictional wetland” means an area that is inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support a prevalence of vegetation typically adapted for life in saturated soil conditions, commonly known as hydrophytic vegetation.
(aa) “Land disturbance activity” means any activity which changes the volume or peak flow discharge rate of rainfall runoff from the land surface. This may include the grading, digging, cutting, scraping, or excavating of soil, placement of fill materials, paving, construction, substantial removal of vegetation, or any activity which bares soil or rock or involves the diversion or piping of any natural or man-made watercourse.
(bb) “Landowner” means the legal or beneficial owner of land, including those holding the right to purchase or lease the land, or any other person holding proprietary rights in the land.
(cc) “Maintenance agreement” means a legally recorded document that acts as a property deed restriction, and which provides for long-term maintenance of storm water management practices.
(dd) “Municipal separate storm sewer system (MS4)” means a conveyance or system of conveyances, including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains owned or operated by the City.
(ee) “Nonpoint source pollution” means pollution from any source other than from any discernible, confined, and discrete conveyances, and shall include, but not be limited to, pollutants from agricultural, silvicultural, mining, construction, subsurface disposal and urban runoff sources.
(ff) “Non-structural controls” means storm water runoff control and treatment techniques that use natural measures to control runoff and/or reduce pollution levels, and do not require extensive construction efforts and/or do promote runoff control and/or pollutant reduction by eliminating the runoff and/or pollutant source. Examples include minimizing impervious area, buffer strips along streams, and preserving natural vegetation.
(gg) “Off-site facility” means a storm water management measure located outside the subject property boundary described in the permit application for land development activity.
(hh) “On-site facility” means a storm water management measure located within the subject property boundary described in the permit application for land development activity.
(ii) “Parcel” means any legally described piece of land created by a partition, subdivision, deed or other instrument recorded with the appropriate entity or agency.
(jj) “Peak rate of runoff” means the maximum rate of runoff for any 24 hour storm of a given frequency.
(kk) “Pre-development conditions” means site conditions as they existed prior to manmade alterations and/or earth disturbing activities.
(ll) “Recharge” means the replenishment of underground water reserves.
(mm) “Redevelopment” means any construction, alteration or improvement exceeding square feet in areas where existing land use is high density commercial, industrial, institutional or multi-family residential.
(nn) “Sediment basin” means a barrier, dam or other facility built to reduce the velocity of water in order to settle and retain sediment.
(oo) “Site development plan” is the written document or set of plans meeting the requirements of this chapter that provides information on the location of the area proposed for development, the site in relation to its general surroundings, and existing characteristics of the site, including limits of earth disturbing activities.
(pp) “Steep slope” means a slope over 18 percent grade, which is characterized by increased run-off, erosion and sediment hazards.
(qq) “Stop work order” means an order issued by the City authorized agent which requires that all work on the site must cease except work associated with bringing the site into compliance with the approved SWP3 or site development plan.
(rr) “Storm water management” means the use of structural or non-structural practices that are designed to reduce storm water runoff pollutant loads, discharge volumes, peak flow discharge rates and detrimental changes in stream temperature that affect water quality and habitat.
(ss) “Storm water management plan (SMP)” is the written document meeting the requirements of this chapter that sets forth the plans and practices to be used to minimize storm water runoff from a site and to safely convey or temporarily store and release post-development storm water runoff at an allowable rate to minimize flooding and erosion.
(tt) “Storm water pollution prevention plan (SWP3)” is the document required by the Ohio EPA for compliance with its NPDES construction activity general permit #OHC000002. The requirements of the SWP3 are required as part of the local jurisdiction's storm water management plan as described above and in this chapter.
(uu) “Storm water retrofit” means a storm water management practice designed for an existing development site that previously had either no storm water management practice in place or a practice inadequate to meet the storm water management requirements of the site.
(vv) “Storm water runoff” means flow on the surface of the ground, resulting from precipitation.
(ww) “Storm frequency” means the average period of time in years within which a storm of a given duration and intensity can be expected to be equaled or exceeded.
(xx) “Structural controls” mean any human-made facility, structure, or device that is constructed to provide temporary storage and/or treatment of storm water runoff. Examples include retention and detention basins, rock check dams, swales, and constructed wetlands.
(yy) “Swale” means a low lying stretch of vegetated land which gathers and carries surface water.
(zz) “Temporary vegetation” means short term vegetative cover such as oats, rye, or wheat, used to stabilize the soil surface until final grading and installation of permanent vegetation.
(aaa) “Water quality volume (WQV)” means the storage needed to capture and treat 90 percent of the average annual storm water runoff volume. Numerically (WQV) will vary as a function of long term rainfall statistical data.
(bbb) “Waters of the State” means surface watercourses and water bodies as defined at 40 CFR 122.2. including all natural waterways and definite channels and depressions in the earth that may carry water, even though such waterways may only carry water during rains and storms and may not carry storm water at and during all times and seasons. Any natural or artificial waterway (including, but not limited to, streams, rivers, creeks, ditches, channels, canals, conduits, culverts, drains, waterways, gullies, ravines, or washes) in which waters flow in a definite direction or course either continuously or intermittently and including any area adjacent thereto which is subject to inundation by reason of overflow of flood water.
(Ord. 5973. Passed 2-20-07.)
(a) Applicability.
(1) This chapter shall apply to both the development and redevelopment of land proposed for the following:
A. Residential, institutional, commercial, office, and industrial purposes, including subdivision and land development proposals for non-agricultural uses in rural areas.
B. Recreational facilities, non-agricultural water impoundments and waterway construction or improvement.
C. Public infrastructure uses, including transportation and utilities.
D. Any earth disturbing activity within critical and sensitive natural areas, including floodplains, highly erodible lands (HEL) and wetlands.
(2) This chapter does not apply to earth disturbing activities associated with agricultural activities.
(b) Responsibility for Administration. The authorized agent shall administer, implement, and enforce the provisions of this chapter. Any powers granted or duties imposed upon the authorized agent may be delegated in writing to persons or entities acting in the beneficial interest of or in the employ of the City.
(c) Severability. The provisions of this chapter are hereby declared to be severable. If any provision, clause, sentence, or paragraph of this chapter or the application thereof to any person, establishment, or circumstances shall be held invalid, such invalidity shall not affect the other provisions or application of this chapter.
(d) Ultimate Responsibility. The standards set forth herein and promulgated pursuant to this chapter are minimum standards; therefore this chapter does not intend nor imply that compliance by any person will ensure that there will be no contamination, pollution, nor unauthorized discharge of pollutants.
(e) Exemptions. Exemption does not exempt any person or persons from other provisions of this chapter or liability from their activities. Any person or persons seeking approval to construct a structure shall be exempted from having to prepare a site development plan or storm water management plan provided they meet all of the following:
(1) Construction takes place on one parcel;
(2) The earth disturbing activity does not affect more than one acre of the development site at a time;
(3) Construction is not located within 100 feet of a sensitive natural area;
(4) Earth disturbing activities will not modify the general existing site drainage pattern(s), drainage structure, drainage tiles, drainage easements, etc.;
(5) One or both of the following:
A. Specifications are obtained and followed for controlling potential off-site storm water and erosion impacts from small lot building sites set forth by the City and/or its authorized agent(s).
B. The parcel is part of an overall development plan which has received approval of a SMP and the developer certifies that they will comply with said plan.
(f) Compatibility with Other Permit and Ordinance Requirements. This chapter is not intended to interfere with, abrogate, or annul any other ordinance, rule or regulation, statute, or other provision of law. The requirements of this chapter should be considered minimum requirements, and where any provision of this chapter imposes restrictions different from those imposed by any other ordinance, rule or regulation, or other provision of law, whichever provisions are more restrictive or impose higher protective standards for human health or the environment shall be considered to take precedence.
(Ord. 5973. Passed 2-20-07.)
(a) Any person or persons proposing to develop or redevelop land within the City for any of the uses listed in Section 1049.03(a) shall design, develop, and submit a site development plan (SDP) as described below. Said plan will be evaluated to determine the potential for erosion, runoff, and sedimentation impacts that may result from such development activities and the need for submission of a storm water management plan (SMP).
(b) No earth disturbing activity subject to regulation under this chapter shall be undertaken for any land proposed for development or redevelopment for uses specified under Section 1049.03(a) without an approved SDP and, if appropriate, an approved SMP.
(c) This final plan must be signed by an Ohio licensed professional engineer (PE), who will verify that the design of all storm water management practices meet the submittal requirements outlined in the Rainwater and Land Development Manual.
(d) Final approval of a proposed development or redevelopment shall not be given unless:
(1) A determination is made by the authorized agent based on submission of a SDP that the proposed earth disturbing activity will not cause accelerated runoff, erosion, and/or sediment impacts harmful to the quality of off-site lands and waters; or
(2) A SMP has been approved by the authorized agent of the City based on the recommendation of its authorized agent that determines that the proposed earth
disturbing activity will not cause accelerated runoff, erosion, and/or sediment impacts harmful to the quality of off-site lands and waters.
(3) Any person seeking approval of land development proposals for use types listed in Section 1049.03(a) shall develop and submit a SDP. The applicant is encouraged to have a pre-submission meeting with the City authorized agent.
(e) Storm Water Design Manual. The Rainwater and Land Development Manual includes a list of acceptable storm water treatment practices, including the specific design criteria and operation and maintenance requirements for each storm water practice. The manual may be updated and expanded from time to time, at the discretion of the local review authority, based on improvements in engineering, science, monitoring and local maintenance experience. Storm water treatment practices that are designed and constructed in accordance with these design and sizing criteria will be presumed to meet the minimum water quality performance standards.
(f) Site Development Plan Requirements.
(1) Each applicant shall provide information that details the location of the area proposed for development, the site in relation to its general surroundings, predevelopment site conditions, existing characteristics of the site, and the extent of proposed earth disturbing activities. At a minimum the plan shall include the following elements:
A. Contact information. The name, address, and telephone number of all persons having a legal interest in the property and the tax reference number and parcel number of the property or properties affected.
B. General location map that shows the area proposed for development and pertinent adjacent areas and features.
C. A description of the nature and type of the earth disturbing/construction activity (e.g. residential, commercial, highway, etc.) *
D. A photocopy of the appropriate soil survey sheet found in the USDA Soil Survey of Montgomery County with location of site identified.
E. A site plan map that shows the location of existing features and proposed improvements on the site including:*
1. Total area of the site and the area of the site that is expected to be disturbed (i.e. grubbing, cleaning, excavation, filling or grading, including off-site borrow areas).*
2. Surface water locations, including springs, wetlands, streams, lakes, water wells, etc., on or within 200 feet of the site, including the boundaries of wetlands or stream channels and first subsequent named receiving water(s) the permittee intends to fill or relocate for which the permittee is seeking approval from the Army Corps of Engineers and/or Ohio EPA.*
3. The general directions of surface water flow and 100-year floodplain when applicable.
4. All improvements, including buildings, retaining walls, sidewalks, streets, parking lots, driveways, utilities and storm water basins, drainage impoundments, channels and outlets, etc.*
5. An estimate of the impervious area and percent imperviousness created by the earth disturbing activity.*
F. Landscaping and stabilization requirements. In addition to the above requirements, a landscaping plan must be submitted with the final design describing the vegetative stabilization and management techniques to be used at a site after construction is completed. This plan will explain not only how the site will be stabilized after construction, but who will be responsible for the maintenance of vegetation at the site and what practices will be employed to ensure that adequate vegetative cover is preserved. This plan must be prepared by a registered landscape architect or by the Montgomery County Soil and Water Conservation District, and must be approved by the authorized agent prior to receiving a permit.
(2) The items in this section marked with an asterisk (*) are also requirements of the storm water pollution prevention plans (SWP3s) required in the Ohio EPA's NPDES Construction Activity Permit #OHC000002, effective April 21, 2003.
(g) Site Development Plan Submission, Review and Action.
(1) Submission of a site development plan by an applicant seeking approval initiates the review process. The City's authorized agent shall review the site development plan and conduct a site inspection of the proposed site. Review of the site development plan shall be completed within ten business days of submittal.
(2) Following the review, the authorized agent shall:
A. Approve the site development plan;
B. Conditionally approve the site development plan pending additional information and/or the incorporation of required changes; or
C. Require the submission of a SMP based on written findings of the authorized agent.
(Ord. 5973. Passed 2-20-07.)
(a) All 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 within the boundaries of the development site.
(b) Discharge of Untreated Storm Water. To the maximum extent practicable the site shall not discharge untreated storm water directly into a receiving body of water.
(c) Structural and Nonstructural Best Management Practices.
(1) Nonstructural storm water 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 storm water management practices shall be designed in accordance with requirements and standards specified in this chapter and/or by the authorized agent.
(3) Structural and nonstructural 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 authorized agent.
(4) In designing storm water detention and retention facilities, water quality benefits shall be considered 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 authorized agent. Buffer width will be determined on a case by case basis using criteria such as floodplain, topography, vegetative cover, canopy cover, and soil types, etc.
(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.
(f) Temporary Stabilization of Disturbed Areas and Soil Stockpiles. A temporary vegetative cover shall be established on disturbed areas as specified in Table 1 below.
Table 1: Temporary Stabilization
Area requiring temporary stabilization | Time frame to apply erosion controls |
Any disturbed areas within 50 feet of a stream and not at final grade. | Within 2 days of the most recent disturbance if that area will remain idle for more than 21 days. |
For all construction activities, any disturbed area, including soil stockpiles, that will be dormant for more than 21 days but less than one year. | Within 7 days of the most recent disturbance within the area. |
Disturbed areas that will be idle over winter. | Prior to onset of winter weather. |
(1) Application practices include vegetative establishment, mulching, and the early application of gravel base on areas to be paved. Soil stabilization measures should be appropriate for the time of year, site conditions and estimated time of use.
(2) Topsoil removed shall be stored on site and shall be stabilized with quick growing plants or other means, so that it is protected from wind and water erosion. Topsoil shall be maintained in a usable condition for sustaining vegetation and reused on the site.
(g) Permanent Stabilization.
(1) A permanent vegetative cover shall be established on disturbed areas as specified in Table 2 below.
Table 2: Permanent Stabilization
Area requiring permanent stabilization | Time frame to apply erosion controls |
Any area that will lie dormant for 6 months or more. | Within 7 days of the most recent disturbance. |
Any area at final grade. | Within 7 days of reaching final grade within that area. |
(2) The following criteria shall apply to revegetation efforts:
A. Reseeding must be done with an annual or perennial cover crop accompanied by placement of straw mulch or its equivalent of sufficient coverage to control erosion until such time as the cover crop is established over 90 percent of the seeded area.
B. Replanting with native woody and herbaceous vegetation must be accompanied by placement of straw mulch or its equivalent of sufficient coverage to control erosion until the plantings are established and are capable of controlling erosion.
C. Any area of revegetation must exhibit survival of a minimum of 75 percent of the cover crop throughout the year immediately following revegetation. Revegetation must be repeated in successive years until the minimum 75 percent survival for one year is achieved.
D. Permanent vegetation shall not be considered established until a ground cover is achieved which is mature enough to control soil erosion and will survive severe weather conditions.
(h) Cut and Fill Slopes. Cut and fill slopes shall be designed, constructed and stabilized in a manner which will minimize erosion. Consideration should be given to the length and steepness of the slope, the soil type, upslope drainage area, groundwater conditions and other applicable factors. If after final grading excessive erosion takes place, additional slope stabilizing measures by the owner, developer or builder will be required until the problem is corrected. The following guidelines are provided to aid in developing an adequate design.
(1) Roughened soil surfaces are generally preferred to smooth surfaces on slopes.
(2) Diversions should be constructed at the top of long steep slopes which have significant drainage areas above the slope. Diversions or terraces may also be used to reduce slope length.
(3) Concentrated storm water should not be allowed to flow down cut or fill slopes unless contained within an adequate channel, flume or slope drain structure.
(4) Wherever a slope face crosses a water seepage plane which endangers the stability of the slope, adequate drainage or other protection should be provided.
(i) Protection of Adjacent Properties/Public Right-of-Ways. Properties, public right-of- ways, and thoroughfares adjacent to the site of an earth disturbing activity shall be protected from sediment deposition. 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.
(j) Sediment Control Structures.
(1) Sediment control structures shall be used to control erosion and trap sediment on a site remaining disturbed for more than 14 days. Such structures may include, but are not limited to, silt fences, storm drain inlet protection, sediment basins and diversions or channels which direct runoff to a sediment basin. All sediment control practices must be capable of ponding runoff in order to be considered functional.
(2) Sediment control structures shall be constructed as a first step in grading and be made functional before upslope earth disturbing activities take place. Earthen structures such as dams, dikes, and diversions shall be seeded and mulched as soon as the installation is complete. Sediment control structures shall be functional throughout the course of earth disturbing activity and until the site is stabilized with permanent vegetation.
(3) Sheet flow runoff from the site shall be intercepted by silt fence or diversions. Silt fence shall be placed on a level contour and shall be capable of temporarily ponding runoff. The relationship between the maximum drainage area to silt fence for a particular slope range is shown in Table 3 below.
Table 3: Maximum Drainage Area to Silt Fence
Maximum drainage area (in acres) to 100 linear feet of silt fence | Range of slope for a particular drainage area (percent) |
0.5 | <2% |
0.25 | 2% but < 20% |
0.125 | 20% but < 50% |
(4) Storm water diversion practices shall be used to keep runoff away from disturbed areas and steep slopes. Such devices, which include swales, dikes or berms, may receive storm water runoff from areas up to ten acres.
(5) Whenever storm water detention is required the storm water runoff from the site shall pass through a sediment basin or other suitable sediment trapping facility before discharge to a receiving water body. The authorized agent(s) may require sediment basins or traps for smaller disturbed areas where deemed necessary.
(k) Stabilization of Waterways and Outlets. All on-site storm water conveyance channels shall be designed and constructed to withstand the expected velocity of flow without erosion. Methods adequate to prevent erosion shall also be provided at the outlets of all pipes and paved channels.
(l) 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.
(m) Working in or Crossing Waters of the State.
(1) All activities shall be kept out of waters of the State to the 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 area stabilized immediately after in-channel work is completed.
(2) Where a water of the State will be crossed regularly during construction, a temporary stream crossing shall be provided, used for the shortest period practical, removed following site construction, and restored as described above.
(n) Maintenance and Removal of Temporary Measures.
(1) All temporary erosion and sediment control practices shall be maintained and repaired to assure continued performance.
(2) All temporary erosion and sediment control measures shall be removed within 30 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.
(o) Control of Construction Site Debris and Wastes. All owners, applicants, contractors and developers shall control 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.
(p) Use, Safety, and Maintenance of Storm Water Practices.
(1) Storm water management practices shall be designed for the ultimate use of the site and function safely and with minimal maintenance.
(2) 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 five days of the inspection. Sediment settling ponds must be repaired or maintained within ten days of the inspection.
(q) Inspection of Storm Water Controls. (See Section 1049.07(e) for specific requirements.)
(1) All on-site control practices shall be periodically inspected to ensure proper function and to identify failures. 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.
(2) Detailed records of inspections shall be maintained for three years by the developer following the final stabilization of the site.
(r) Accessibility and Easements. (See Section 1049.07(c) 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.
(s) 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.
(Ord. 5973. Passed 2-20-07.)
(a) Any person or persons seeking approval for an earth disturbing activity listed below shall prepare a SMP as described in this chapter.
(1) Activities disturbing greater than or equal to one acre, or less than one acre, if part of a larger common plan of development or sale.
(2) Activities that require the extension of public utilities (roadways, water mains, sanitary sewer mains, storm sewers, etc.).
(3) Activities that will modify an existing and/or approved drainage way, drainage structure, and/or drainage easement.
(4) Activities that will channelize, straighten, and/or modify a watercourse within the identified 100 year floodplain (studied and unstudied).
(b) SMPs are intended to provide information on all soil erosion and runoff control activities and best management practices (BMPs) to be used and incorporated on the site both during and after site development. This information includes, but is not limited to, site grading, storm water management facilities and practices, erosion and runoff control information, maintenance plans, and other measures that focus on managing the effects of earth disturbing activities that occur as a result of site development.
(c) Each SMP shall provide site designs that meet the performance standards presented in this chapter and provide practical treatment for both water quality and quantity of storm water from the site as appropriate.
(d) In general, the SMP needs to address:
(1) Erosion and sediment control. Providing measures to insure that earth disturbing activities at the site during and after development will be managed in a manner that will not result in increased erosion and sedimentation from the site resulting in impacts to water quality and that meet the performance standards.
(2) Runoff control. Providing measures to insure that the quantity of surface water runoff from the development site during and after construction will mimic the pre-development conditions and that meet the performance standards.
(e) If a SMP is required, such plan shall specifically include all the following:
(1) The minimum elements required in the site development plan;
(2) The contents of the storm water pollution prevention plan (SWP3) required by the Ohio EPA's NPDES Construction Activity Permit #OHC000002 and incorporated here by reference. This plan may be submitted as developed for the Ohio EPA, in conjunction with the other requirements of this section.
(3) The contents of the Ohio EPA's SWP3 include, but are not limited to:
A. A description of prior land uses at the site.
B. Existing data describing the soils on the site and, if available, the quality of any discharge from the site.
C. A determination of runoff coefficients for both the pre-construction and post construction site conditions.
D. For all large earth-disturbing activities (involving the disturbance of five or more acres of land or will disturb less than five acres, but part of a larger common plan of development or sale which will disturb five or more acres of land), a description of post construction BMP(s) chosen and designed to detain and treat a water quality volume (WQ
V
) equivalent to the volume of runoff from a 0.75-inch rainfall (See Ohio EPA Construction Activity Permit for methodology).
E. For all small earth-disturbing activities (which disturb one or more, but less than five acres of land and is not a part of a larger common plan of development or sale which will disturb five or more acres of land), a description of measures that will be installed during the development process to control pollutants in storm water discharges that will occur after construction operations have been completed.
F. An implementation schedule which describes the sequence of major construction operations (i.e., grubbing, excavating, grading, utilities and infrastructure installation) and the implementation of erosion, sediment and storm water management practices or facilities to be employed during each operation of the sequence.
G. For subdivided developments where the SWP3 does not call for a centralized sediment control capable of controlling multiple individual lots, a detail drawing of a typical individual lot showing standard individual lot erosion and sediment control practices.
H. A detailed description of the storm water controls to be incorporated and how these meet or exceed the appropriate performance standards presented in this chapter. This shall include the identification of which entity (developer, contractor, owner) is responsible for implementation of each individual control (e.g., contractor A will clear land and install perimeter controls and contractor B will maintain perimeter controls until final stabilization).
I. A detailed maintenance plan that describes procedures (e.g. inspections) needed to ensure the continued performance of control practices. Such plans must ensure that pollutants collected within structural post-construction practices, be disposed of in accordance with local, State, and Federal regulations.
J. A site map that includes:
1. Limits of earth-disturbing activity of the site including associated off- site borrow or spoil areas.
2. Soil types on the site, including locations of unstable or highly erodible soils.
3. Existing and proposed contours. A delineation of drainage watersheds expected during and after major grading activities as well as the size of each drainage watershed, in acres.
4. Existing and planned locations of buildings, roads, parking facilities and utilities.
5. The location of all erosion and sediment control practices, including areas likely to require temporary stabilization during site development.
6. Sediment and storm water management basins noting their sediment settling volume and contributing drainage area.
7. Permanent storm water management practices to be used to control pollutants in storm water after construction operations have been completed.
8. Areas designated for the storage or disposal of solid, sanitary, and toxic wastes, including dumpster areas, cement truck washout areas, and vehicle fueling and maintenance.
9. The location of designated construction entrances where vehicles will access the site.
10. The location of any in-stream activities, including stream crossings.
(4) Copies of pertinent notices of intent (NOI), permits, public notices and letters of authorization must be included with SMP submissions. These may include, but are not limited to, Ohio EPA NPDES permits authorizing storm water discharges associated with construction activity, Ohio EPA Phase II Storm Water Permits, Section 401 and 404 Clean Water Act Permits, Ohio EPA Isolated Wetland Permit, and Ohio Dam Safety Law Permits.
(5) Supplemental requirements as provided below.
(f) Storm water discharge to critical areas with sensitive resources (i.e. wetlands, steep slopes, scenic river designation, recharge areas, etc.) may be subject to additional criteria, or may need to utilize or restrict certain storm water practices.
(g) Supplemental Post Construction Requirements.
(1) Determination of post development runoff.
A. Each SMP shall include an evaluation of pre-development conditions together with during, and post-development impacts that quantifies the volume and rate of runoff from the site by subdrainage areas. This evaluation shall be prepared according to methods prescribed in the latest edition of Rainwater and Land Development or other appropriate sources. The evaluation shall:
1. Show delineation and sequence of subdrainage units which comprise the area proposed for development.
2. Indicate the hydraulic length of slope per individual subdrainage unit and the length of the natural or manmade watercourse which accommodates the surface runoff from each subdrainage unit.
3. Indicate within the legend the average percent slope, erosion factor (K) and runoff curve number (CN) per individual subdrainage unit for a 24-hour storm of a one-year frequency.
4. Include a hydrograph for a 24-hour storm of the critical frequency to be controlled as determined below in this chapter and all calculations made pertinent to evaluating the effects of the proposed development on the pre-development runoff conditions of the site.
B. Calculations for the design of storm water management facilities shall demonstrate the following for each subdrainage unit:
1. The peak rate of runoff from the critical storm and all more frequent storms occurring on the site does not exceed the peak rate of runoff from a one year frequency, 24 hour storm occurring on the same site under pre-development conditions.
2. Storms of less frequent occurrence than the critical storm, up to the 100 year storm shall have its peak runoff rates no greater than the peak runoff rates from equivalent storms under pre-development conditions. Consideration of the 1, 2, 5, 10, 25, 50, and 100 year storms in design and construction will be considered meeting this standard.
3. Calculation of a critical storm for each subdrainage unit of the site shall be determined as follows:
a. Calculate by appropriate hydrologic methods, such as the NRCS Technical Release 55, the total volume of runoff from a one-year frequency, 24-hour storm occurring on the development area before, during, and after development.
b. From the volumes determined in a. above, determine the percentage increase in volume of runoff due to the proposed development, and using this percentage, select the 24-hour critical storm from this table:
If the percentage of increase in volume of runoff is (see chart below):
% Equal To or Greater Than | % Less Than | The Critical Storm for Peak Rate Control |
% Equal To or Greater Than | % Less Than | The Critical Storm for Peak Rate Control |
- | 10 | 1 year |
10 | 20 | 2 years |
20 | 50 | 5 years |
50 | 100 | 10 years |
100 | 250 | 25 years |
250 | 500 | 50 years |
500 | - | 100 years |
4. The City's authorized agent shall approve or reject any calculation method based on its technical validity for the given situation.
(2) Off-site storm water control facilities. Exceptions to requiring permanent on-site runoff control on the site may be considered by the City authorized agent provided the applicant can prove that:
A. The intent and standards of this chapter for runoff control can be best achieved by the utilization of off-site storm water control facilities.
B. Runoff from the site can be conveyed to off-site storm water facilities in a manner and by means which satisfies or surpasses the standards of this chapter.
C. The applicant has ownership of or the right to use the off-site facility in question.
(3) Maintenance and repair plan. The design and planning of all storm water management facilities shall include detailed maintenance and repair procedures to ensure their continued function. These plans will identify the parts or components of a storm water management facility that need to be maintained and the equipment and skills or training necessary. Provisions for the periodic review and evaluation of the effectiveness of the maintenance program and the need for revisions or additional maintenance procedures shall be included in the plan.
(4) Landscaping plans required. All storm water management practices must have a landscaping plan detailing both the vegetation to be in the practice and how and who will manage and maintain this vegetation. The applicant must present a detailed plan for management of vegetation at the site after construction is finished, including who will be responsible for the maintenance of vegetation at the site and what practices will be employed to ensure that adequate vegetative cover is preserved. This plan must be prepared by a registered landscape architect or the Montgomery County Soil and Water Conservation District.
(5) Maintenance easements. The applicant must ensure access to all storm water treatment practices at the site for the purpose of inspection and repair by securing all the maintenance easements needed on a permanent basis. These easements will be recorded with the plan and will remain in effect even with transfer of title to the property.
(6) Maintenance agreement. The applicant must execute an easement and an inspection and maintenance agreement binding on all subsequent owners of land served by an on- site storm water management measure in accordance with the specifications of this chapter.
(7) Other environmental permits. The applicant shall assure that all other applicable environmental permits have been acquired for the site prior to approval of the final storm water design plan.
(h) Storm Water Management Plan Submission, Review and Action.
(1) The applicant is encouraged to have a pre-submission meeting with the City's authorized agent(s).
(2) Submission of two sets of the SMP and other supporting data required by this regulation to the authorized agent of the City completes the applicant's responsibilities and initiates the review process.
(3) The SMP shall be reviewed by the City authorized agent(s) to:
A. Verify background information furnished by the applicant and evaluate the proposed development in relation to existing site conditions.
B. Assess the SMP in relation to the performance standards and requirements of this chapter.
(4) Upon submission of the SMP the City authorized agent(s) shall complete a review of the SMP within ten business days.
(5) The City authorized agent shall either:
A. Approve the SMP as submitted by the applicant;
B. Conditionally approve the SMP and require the submission of additional and/or revised information by the applicant, in order to fully meet the intent and standards of this chapter; or
C. Disapprove the SMP.
(6) Revisions to conditionally approved SMPs shall be prepared and submitted by the applicant to the City authorized agent(s) for review.
(7) Action by the approval authority and/or the authorized agent(s) approving or disapproving the SMP is a final order for purposes of judicial review.
(i) Construction Inspection.
(1) Notice of construction commencement.
A. The applicant must notify the City authorized agent ten business days in advance before the commencement of construction. Regular inspections of the storm water management system construction shall be conducted by the authorized agent of the City or certified by a professional engineer or their designee who has been approved by the City. All inspections shall be documented and written reports prepared that contain the following information:
1. The date and location of the inspection;
2. Whether construction is in compliance with the approved storm water management plan;
3. Variations from the approved construction specifications; and
4. Any violations that exist.
B. If any violations are found, the property owner shall be notified in writing of the nature of the violation and the required corrective actions. No added work shall proceed until any violations are corrected and all work previously completed has received approval by the City authorized agent.
(2) As built plans. All applicants are required to submit actual “as built” plans for any storm water management practices located on-site after final construction is completed. The plan must show the final design specifications for all storm water management facilities and must be certified by a professional engineer. A final inspection by the City authorized agent is required before the release of any performance securities can occur.
(Ord. 5973. Passed 2-20-07.)
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