(a) General. The stormwater system, including SCMs for storage, treatment and control, and conveyance facilities, shall be designed to prevent structure flooding during the 100-year, twenty-four (24) hour storm event; to maintain predevelopment runoff patterns, flows, and volumes; to meet the requirements of the Construction General Permit; and to meet the following criteria:
(1) Integrated SCMs that address degradation of water resources. The SCMs shall function as an integrated system that controls flooding and minimizes the degradation of the water resources receiving stormwater discharges from the site. Acceptable SCMs shall:
A. Not disturb riparian areas unless the disturbance is intended to support a watercourse restoration project and complies with Chapter 1161.
B. Maintain predevelopment hydrology and groundwater recharge on as much of the site as practicable. Where feasible, bioretention, permeable pavement with infiltration, underground storage with infiltration, infiltration trenches, infiltration basins, and/or rainwater harvesting must be the water quality SCMs used. Separate SCMs may be used for peak discharge control and water quality treatment.
C. Only install new impervious surfaces and compact soils where necessary to support future land use.
D. Compensate for increased runoff volumes caused by new impervious surfaces and soil compaction by reducing stormwater peak flows to less than predevelopment levels.
E. Be designed according to the methodology included in the most current edition of Rainwater and Land Development Manual or another design manual acceptable for use by the City of Garfield Heights and Ohio EPA.
(2) Practices designed for final use. SCMs shall be designed to achieve the stormwater management objectives of this regulation, to be compatible with the proposed post-construction use of the site, to protect the public health, safety, and welfare, and to function safely with routine maintenance.
(3) Stormwater management for all lots. Areas developed for a subdivision, as defined in Chapter Section 1100 of the Planning and Zoning Code shall provide stormwater management and water quality controls for the development of all subdivided lots. This shall include provisions for lot grading and drainage that prevent structure flooding during the 100-year, twenty-four (24) hour storm; and maintain, to the extent practicable, the pre-development runoff patterns, volumes, and peaks from each lot.
(4) Stormwater facilities in water resources. SCMs and related activities shall not be constructed in water resources unless the applicant shows proof of compliance with all appropriate permits from the Ohio EPA, the U.S. Army Corps, and other applicable federal, state, and local agencies as required in Section 1170.07 of this regulation, and the activity is in compliance with Chapter 1171 Erosion and Sediment Control, and Chapter 1161 Riparian Setbacks, all as determined by the City Engineer.
(5) Stormwater ponds and surface conveyance channels. All stormwater pond and surface conveyance designs must provide a minimum of two (2) foot freeboard above the projected peak stage within the facility during the 100-year, twenty-four (24) hour storm. When designing stormwater ponds and conveyance channels, the applicant shall consider public safety as a design factor and alternative designs must be implemented where site limitations would preclude a safe design.
(6) Exemption. The site where soil-disturbing activities are conducted shall be exempt from the requirements of Section 1170.09 if it can be shown to the satisfaction of the City Engineer that the site is part of a larger common plan of development where the stormwater management requirements for the site are provided by an existing SCM, or if the stormwater management requirements for the site are provided by SCMs defined in a regional or local stormwater management plan approved by the City Engineer.
(7) Maintenance: All SCMs shall be maintained in accordance with the Inspection and Maintenance Plan and Agreements approved by the City Engineer.
(8) Ownership. Unless otherwise required by the City of Garfield Heights, SCMs serving multiple lots in subdivisions shall be on a separate lot held and maintained by an entity of common ownership or, if compensated by the property owners, by the City of Garfield Heights as a dedicated public space. SCMs serving single lots shall be placed on these lots, protected within an easement, and maintained by the property owner.
(9) Preservation of Existing Natural Drainage. Practices that preserve the existing natural drainage shall be used to the maximum extent practicable. Such practices may include minimizing site grading and compaction; protecting and/or restoring water resources, riparian areas, and existing vegetation and vegetative buffer strips; phasing of construction operations in order to minimize the amount of disturbed land at any one time, and designation of tree preservation areas or other protective clearing and grubbing practices; and maintaining unconcentrated stormwater runoff to and through these areas.
(10) Post-Construction Soil Restoration. Except for areas that will be covered by impervious surface or have been incorporated into an SCM, the soil moistureholding capacity of areas that have been cleared and graded must be restored to that of the original, undisturbed soil to the maximum extent practicable. Areas that have been compacted or had the topsoil or duff layer removed should be amended using the soil profile restoration design criteria in the Rainwater and Land Development Manual.
(b) Stormwater Conveyance Design Criteria. All SCMs shall be designed to convey stormwater to allow for the maximum removal of pollutants and reduction in flow velocities.
This shall include but not be limited to:
(1) Surface water protection. The City Engineer may allow modification to streams, rivers, lakes, wetlands or other surface waters only if the applicant shows proof of compliance with all appropriate permits from the Ohio EPA, the U.S. Army Corps, and other applicable federal, state, and local agencies as required in Section 1170.07 of this regulation, and the activity is in compliance with Section Chapter 1171 and Chapter 1172, all as determined by the City Engineer.
At a minimum, stream relocation designs must show how the project will minimize changes to the vertical stability, floodplain form, channel form, and habitat of upstream and downstream channels on and off the property. Design modification to existing streams, rivers, lakes and wetlands within FEMA designated floodways will require the Owner to apply for the appropriate mapping modifications per FEMA regulations. The cost for such a plan modification shall be born by the land owner.
(2) Off-site stormwater discharges. Off-site stormwater runoff that discharges to or across the applicant’s development site shall be conveyed through the stormwater conveyance system planned for the development site at its existing peak flow rates during each design storm. Off-site flows shall be diverted around stormwater quality control facilities, or the stormwater quality control facility shall be sized to treat the off-site flow. Comprehensive Stormwater Management Plans will not be approved until it is demonstrated to the satisfaction of the City Engineer that off-site runoff will be adequately conveyed through the development site in a manner that does not exacerbate upstream or downstream flooding and erosion.
(3) Sheet flow. The site shall be graded in a manner that maintains sheet flow over as large an area as possible. The maximum area of sheet flow shall be determined based on the slope, the uniformity of site grading, and the use of easements or other legally-binding mechanisms that prohibit regrading and/or the placement of structures within sheet flow areas. The sheet flow length shall not exceed seventy-five (75) feet from impervious area or 150 feet from pervious areas. Flow shall be directed into an open channel, storm sewer, or other SCMs from areas too long and/or too large to maintain sheet flow, all as determined by the City Engineer.
(4) Open channels. Unless otherwise allowed by the City Engineer, drainage tributary to SCMs shall be provided by an open channel with vegetated banks and designed to carry the ten (10) year, twenty-four (24) hour stormwater runoff from upstream contributory areas.
(5) Open drainage systems. Open drainage systems shall be preferred on all new development sites to convey stormwater where feasible. Storm sewer systems shall be allowed only when the site cannot be developed at densities allowed under City of Garfield Heights zoning or where the use of an open drainage system affects public health or safety, all as determined by the City Engineer. The following criteria shall be used to design storm sewer systems when necessary: NOTE: The following sections are typical stormwater conveyance design criteria. Either use these criteria or include the pertinent sections of your existing stormwater conveyance design criteria.
A. Storm sewers shall be designed such that they do not surcharge from runoff caused by the five (5) year, twenty-four (24) hour storm, and that the hydraulic grade line of the storm sewer stays below the gutter flow line of the overlying roadway, or below the top of drainage structures outside the roadway during a ten (10) year, twenty-four (24) hour storm. The system shall be designed to meet these requirements when conveying the flows from the contributing drainage area within the proposed development and existing flows from offsite areas that are upstream from the development.
B. The minimum inside diameter of pipe to be used in public storm sewer systems is twelve (12) inches. Smaller pipe sizes may be used in private systems, subject to the approval of the City Engineer.
C. All storm sewer systems shall be designed taking into consideration the tailwater of the receiving facility or water resource. The tailwater elevation used shall be based on the design storm frequency. The hydraulic grade line for the storm sewer system shall be computed with consideration for the energy losses associated with entrance into and exit from the system, friction through the system, and turbulence in the individual manholes, catch basins, and junctions within the system.
D. The inverts of all curb inlets, manholes, yard inlets, and other structures shall be formed and channelized to minimize the incidence of quiescent standing water where mosquitoes may breed.
E. Headwalls shall be required at all storm sewer inlets or outlets to and from open channels or lakes. Designs where the open flow channel is steeper than or equal to one percent (1%) shall include a stone rip-wrap or other approved erosion control measure as approved by the City Engineer.
(6) Water Resource Crossings. The following criteria shall be used to design structures that cross a water resource in the City of Garfield Heights:
A. Water resource crossings other than bridges shall be designed to convey the stream's flow for the minimum twenty-five (25) year, twenty-four (24) hour storm.
B. Bridges, open bottom arch or spans are the preferred crossing technique and shall be considered in the planning phase of the development. Bridges and open spans should be considered for all State Scenic Rivers, coldwater habitat, exceptional warmwater habitat, seasonal salmonid habitat streams, and Class III headwater streams. The footers or piers for these bridges and open spans shall not be constructed below the ordinary high-water mark.
C. If a culvert or other closed bottom crossing is used, twenty-five percent (25%) of the cross sectional area or a minimum of one (1) foot of box culverts and pipe arches must be embedded below the channel bed. The conduit or conveyance must be sized to carry the twenty-five (25) year storm under these conditions.
D. The minimum inside diameter of pipes to be used for crossings shall be twelve (12) inches.
E. The maximum slope allowable shall be a slope that produces a 10-fps velocity within the culvert barrel under design flow conditions. Erosion protection and/or energy dissipaters shall be required to properly control entrance and outlet velocities.
F. All culvert installations shall be designed with consideration for the tailwater of the receiving facility or water resource. The tailwater elevation used shall be based on the design storm frequency.
G. Headwalls shall be required at all culvert inlets or outlets to and from open channels or lakes.
H. Streams with a drainage area of five (5) square miles or larger shall incorporate floodplain culverts at the bankfull elevation to restrict head loss differences across the crossing so as to cause no rise in the 100-year storm event.
I. Bridges shall be designed such that the hydraulic profile through a bridge shall be a minimum of one (1) foot below the bottom chord of the bridge for either the 100-year, twenty-four (24) hour storm, or the 100-year flood elevation as determined by FEMA, whichever is more restrictive.
(7) Overland flooding. Overland flood routing paths shall be used to convey stormwater runoff from the 100-year, twenty-four (24) hour storm event to an adequate receiving water resource or SCM such that the runoff is contained within the drainage easement for the flood routing path and does not cause flooding of buildings or related structures. The peak 100-year water surface elevation along flood routing paths shall be at least two feet below the finished grade elevation of all structures. When designing the flood routing paths, the conveyance capacity of the site's storm sewers shall be taken into consideration.
(8) Compensatory flood storage mitigation. In order to preserve floodplain storage volumes and thereby avoid increases in water surface elevations, any filling within floodplains approved by the City of Garfield Heights must be compensated by providing an equivalent storage volume. First consideration for the location(s) of compensatory floodplain volumes should be given to areas where the stream channel will have immediate access to the new floodplain within the limits of the development site. Consideration will also be given to enlarging existing or proposed retention basins to compensate for floodplain fill if justified by a hydraulic analysis of the contributing watershed. Unless otherwise permitted by the City of Garfield Heights, reductions in volume due to floodplain fills must be mitigated within the legal boundaries of the development. Embankment slopes used in compensatory storage areas must reasonably conform to the natural slopes adjacent to the disturbed area. The use of vertical retaining structures is specifically prohibited.
(9) Velocity dissipation. Velocity dissipation devices shall be placed at discharge locations and along the length of any outfall to provide non-erosive flow velocity from the structure to a water resource so that the natural physical and biological characteristics and functions of the water resource are maintained and protected
(c) Stormwater Quality Control. The site shall be designed to direct runoff to one (1) or more SCMs that meet or exceed the criteria in the Construction General Permit.
(1) Direct runoff to a BMP. The site shall be designed to direct runoff to one (1) or more of the following storm water management practices. These practices are listed in Table 2 of this regulation and shall be designed to meet the following general performance standards:
A. Extended conveyance facilities that slow the rate of storm water runoff; filter and biodegrade pollutants in storm water; promote infiltration and evapotranspiration of storm water; and discharge the controlled runoff to a water resource.
B. Extended detention facilities that detain storm water; settle or filter particulate pollutants; and release the controlled storm water to a water resource.
C. Infiltration facilities that retain storm water; promote settling, filtering, and biodegradation of pollutants; and infiltrate captured storm water into the ground. The City Engineer may require a soil engineering report to be prepared for the site to demonstrate that any proposed infiltration facilities meet these performance standards.
D. The City Engineer may approve other BMPs if the applicant demonstrates to the City Engineer satisfaction that these BMPs meet the objectives of this regulation as stated in Section 1170.09 (c)(6).
(2) Criteria applying to all storm water management practices. Practices chosen must be sized to treat the water quality volume (WQv) and to ensure compliance with Ohio Water Quality Standards (OAC Chapter 3745-1).
A. The WQv shall be equal to the volume of runoff from a 0.75 inch rainfall event and shall be determined according to one of the following methods:
1. Through a site hydrologic study approved by the City Engineer that uses continuous hydrologic simulation; site- specific hydrologic parameters, including impervious area, soil infiltration characteristics, slope, and surface routing characteristics; proposed best management practices controlling the amount and/or timing of runoff from the site; and local long-term hourly records, or
2. Using the following equation:
WQv = C*P*A/12
where terms have the following meanings:
WQv = water quality volume in acre-feet
C = runoff coefficient appropriate for storms less than 1 in.
P = 0.75 inch precipitation depth
A = area draining into the storm water practice, in acres.
Runoff coefficients required by the Ohio Environmental Protection Agency (Ohio EPA) for use in determining the water quality volume are listed in Table 1. Alternatively, the City Engineer may consider use of the following equation to calculate the runoff coefficient if the applicant can demonstrate that appropriate controls are in place to limit the proposed impervious area of the development:
C=0.858i3 – 0.78i2 + 0.774i+0.04, where:
i = fraction of the drainage area that is impervious
Table 1: Runoff Coefficients Based on the Type of Land Use
Land Use | Runoff Coefficient |
Industrial & Commercial | 0.8 |
High Density Residential (>8 dwellings/acre) | 0.5 |
Medium Density Residential (4 to 8 dwellings/acre) | 0.4 |
Low Density Residential (<4 dwellings/acre) | 0.3 |
Open Space and Recreational Areas | 0.2 |
Where land use will be mixed, the runoff coefficient should be calculated using a weighted average. For example, if sixty percent (60%) of the contributing drainage area to the storm water treatment structure is Low Density Residential, thirty percent (30%) is High Density Residential, and ten percent (10%) is Open Space, the runoff coefficient is calculated as follows (0.6)(0.3)+(0.3)(0.5)+(0.1)(0.2) = (0.35) | |
B. An additional volume equal to twenty percent (20%) of the WQv shall be incorporated into the storm water practice for sediment storage.
C. Storm water quality management practices shall be designed such that the drain time is long enough to provide treatment and protect against downstream bank erosion, but short enough to provide storage available for successive rainfall events as defined in Table 2.
Table 2: Draw Down Times for Storm Water Management Practices
Best Management Practice | Drain Time of WQv |
Infiltration Facilities | 24 - 48 hours |
Extended Conveyance Facilities (Vegetated Swales, Filter Strips) Extended Conveyance Detention Design Flow Through Design | 24 hours * |
Extended Detention Facilities Extended Dry Detention Basins | 48 hours |
Wet Detention Basins ** | 24 hours |
Constructed Wetlands (above permanent pool) | 24 hours |
Media Filtration, Bioretention | 40 hours |
* Size to pass a hydrograph with a volume equal to the WQv, a duration of two (2) hours, and peak rainfall intensity of one (1) inch/hour at a depth of no more than three (3) inches. The use of this criterion is limited to sites where the total area disturbed is five (5) acres or less. **Provide both a permanent pool and an extended detention volume above the permanent pool, each sized with at least 0.75*WQV . |
D. Each practice shall be designed to facilitate sediment removal, vegetation management, debris control, and other maintenance activities defined in the Inspection and Maintenance Agreement for the site.
(3) Additional criteria applying to infiltration facilities.
A. Infiltration facilities shall only be allowed if the soil of the facility falls within hydrologic soil groups A or B, and if the seasonal high water table and any underlying bedrock are at least six feet below the final grade elevation.
B. All runoff directed into an infiltration basin must first flow through an extended conveyance facility to remove coarser sediments that could cause a loss of infiltration capacity.
C. During construction, all runoff from disturbed areas of the site shall be diverted away from the proposed infiltration basin site. No construction equipment shall be allowed within the infiltration basin site to avoid soil compaction.
(4) Additional criteria applying to extended conveyance facilities.
A. Facilities shall be lined with fine turf-forming, flood tolerant grasses.
B. Facilities designed according to the extended conveyance detention design drain time shall:
1. Not be located in areas where the depth to bedrock and/or seasonal high-water table is less than three (3) feet below the final grade elevation.
2. Only be allowed where the underlying soil consists of hydrologic soil group (HSG) A or B, unless the underlying soil is replaced by at least a two and one-half (2.5)-foot-deep layer of soil amendment with a permeability equivalent to a HSG A or B soil and an underdrain system is provided.
C. Facilities designed according to the flow through design drain time shall:
1. Only be allowed on sites where the total area disturbed is five (5) acres or less.
2. Be designed to slow and filter runoff flowing through the turf grasses with a maximum depth of flow no greater than three (3) inches.
D. Concentrated runoff shall be converted to sheet flow before entering an extended conveyance facility designed according to the flow through drain time.
(5) Additional criteria for extended detention facilities:
A. The outlet shall be designed to release the bottom fifty percent (50%) of the water quality volume in no less than two-third (2/3rd) of the drain time. A valve shall be provided to drain any permanent pool volume for removal of accumulated sediments. The outlet shall be designed to minimize clogging, vandalism, and maintenance. Methods of inspecting and testing shall be incorporated in the long term maintenance plan for the site and shall be required to be tested at least annually.
B. The basin design shall incorporate the following features to maximize multiple uses, aesthetics, safety, and maintainability:
1. Basin side slopes above the permanent pool shall have a run to rise ratio of 4:1 or flatter.
2. The perimeter of all permanent pool areas deeper than four (4) feet shall be surrounded by an aquatic bench that extends at least eight (8) feet and no more than fifteen (15) feet outward from the normal water edge. The eight (8) feet wide portion of the aquatic bench closest to the shoreline shall have an average depth of six (6) inches below the permanent pool to promote the growth of aquatic (non-invasive) vegetation. The remainder of the aquatic bench shall be no more than fifteen (15) inches below the permanent pool to minimize drowning risk to individuals who accidentally or intentionally enter the basin, and to limit growth of dense vegetation in a manner that allows waves and mosquito predators to pass through the vegetation. The maximum slope of the aquatic bench shall be ten (10) (H) to one (1) (V). The aquatic bench shall be planted with hearty plants comparable to wetland vegetation that are able to withstand prolonged inundation.
3. A forebay designed to allow larger sediment particles to settle shall be placed at basin inlets. The forebay volume shall be equal to at least ten percent (10%) of the water quality volume (WQv).
(6) Additional criteria applying to extended conveyance facilities.
A. Facilities shall be lined with fine turf-forming, flood tolerant grasses.
B. Facilities designed according to the extended detention design drain time shall:
1. Not be located in areas where the depth to bedrock and/or seasonal high water table is less than three (3) feet below the final grade elevation.
2. Only be allowed where the underlying soil consists of hydrologic soil group (HSG) A or B, unless the underlying soil is replaced by at least a two and one-half (2.5) foot deep layer of soil amendment with a permeability equivalent to a HSG A or B soil and an under drain system is provided.
C. Swales and filter strips designed according to the flow through drain time shall:
1. Only be allowed on sites where the total area disturbed is five (5) acres or less.
2. Be designed to slow and filter runoff flowing through the turf grasses with a maximum depth of flow no greater than three (3) inches.
D. Concentrated runoff shall be converted to sheet flow before entering an extended conveyance facility designed according to the flow through drain time.
(7) Alterative post-construction BMPs. The applicant may request approval from the City Engineer for the use of alternative structural post-construction BMPs if the applicant shows, to the satisfaction of the City Engineer and with prior written approval from Ohio EPA, that these BMPs are equivalent in pollutant removal and runoff flow/volume reduction effectiveness to those listed in Table 2.
(d) Stormwater Quantity Control. The Comprehensive Stormwater Management Plan shall describe how the proposed SCMs are designed to meet the following requirements for stormwater quantity control for each watershed in the development:
(1) The peak discharge rate of runoff from the Critical Storm and all more frequent storms occurring under post-development conditions shall not exceed the peak discharge rate of runoff from a one (1) year, twenty-four (24) hour storm occurring on the same development drainage area under predevelopment conditions.
(2) Storms of less frequent occurrence (longer return periods) than the Critical Storm, up to the 100-year, twenty-four (24) hour storm shall have peak runoff discharge rates no greater than the peak runoff rates from equivalent size storms under predevelopment conditions. The 1, 2, 5, 10, 25, 50, and 100-year storms shall be considered in designing a facility to meet this requirement.
(3) The Critical Storm for each specific development drainage area shall be determined as follows:
A. Determine, using a curve number-based hydrologic method or other hydrologic method approved by the City Engineer, the total volume (acre-feet) of runoff from a one (1) year, twenty-four (24) hour storm occurring on the development drainage area before and after development. These calculations shall meet the following standards:
1. Calculations shall include the lot coverage assumptions used for full build out as proposed.
2. Calculations shall be based on the entire contributing watershed to the development area.
3. Model pervious, directly connected impervious and disconnected impervious areas as separate subwatersheds.
4. Drainage area maps shall include area, curve number, and time of concentrations. Time of concentration shall also show the flow path and the separation in flow type.
5. Use the Precipitation-Frequency Atlas of the United States, NOAA Atlas 14, Vol 2(3). [available online: http://hdsc.nws.noaa.gov/hdsc/pfds/] for rainfall depth data for stormwater design.
6. Use the SCS Type II rainfall distribution for all design events with a recurrence interval greater than one (1) year. Include lot coverage assumptions used for full build out of the proposed condition.
7. Curve numbers for the pre-development condition shall reflect the average type of land use over the past ten (10) years and not only the current land use.
i. Pre-development Curve Numbers – For wooded or brushy areas, use listed values from TR-55 NRCS USDA Urban Hydrology for Small Watersheds, 1986 in good hydrologic condition. For meadows, use listed values. For all other areas (including all types of agriculture), use pasture, grassland, or range in good hydrologic condition.
ii. Post-development Curve Numbers - Open space areas shall use post-construction hydrologic soil groups from Rainwater and Land Development unless the soil is amended using the soil profile restoration design criteria in Rainwater and Land Development Manual. All undisturbed areas or open space with amended soils shall be treated as “open space in good condition.”
8. Time of Concentration - Use velocity-based methods from (TR-55 NRCS USDA Urban Hydrology in Small Watersheds, 1986) to estimate travel time (Tt) for overland (sheet) flow, shallow concentrated flow and channel flow.
i. Maximum sheet flow length is 100 ft.
ii. Use the appropriate “unpaved” velocity equation for shallow concentrated flow from Soil Conservation Service National Engineer Handbook Section 4 – Hydrology (NEH-4).
9. The volume reduction provided by runoff reduction SCMs may be subtracted from the post-development stormwater volume. Volume reductions for these SCMs may be demonstrated using methods outlined in Rainwater and Land Development or a hydrologic model acceptable to the City Engineer.
B. To account for future post-construction improvements to the site, calculations shall assume an impervious surface such as asphalt or concrete for all parking areas and driveways except in instances of engineered permeable pavement systems. From the volume determined in Section 1170.09(d)(3)A., determine the percent increase in volume of runoff due to development. Using the percentage, select the twenty-four (24) hour Critical Storm from Table 3.
(e) Stormwater Management for Previously Developed Areas. SCMs on previously
developed sites must meet the criteria in the Construction General Permit.
Table 3: 24-Hour Critical Storm
If the Percentage of Increase in Volume of Runoff is: | The Critical Storm will be: | |
Equal to or Greater Than: | and Less Than: | |
---- | 10 | 1 year |
10 | 20 | 2 year |
20 | 50 | 5 year |
50 | 100 | 10 year |
100 | 250 | 25 year |
250 | 500 | 50 year |
500 | --- | 100 year |
For example, if the percent increase between the pre- and post-development runoff volume for a one (1) year storm is thirty-five percent (35%), the Critical Storm is a five (5) year storm. The peak discharge rate of runoff for all storms up to this frequency shall be controlled so as not to exceed the peak discharge rate from the one (1) year frequency storm under pre-development conditions in the development drainage area. The post- development runoff from all less frequent storms need only be controlled to meet pre-development peak discharge rates for each of those same storms. | ||
(Ord. 60-2023. Passed 8-14-23.)