City of O'Fallon, MO Article V Development Standards

Section 405.130 Initial Considerations.

[R.O. 2008 § 405.130; Ord. No. 6496, 9-13-2018]

In the City Council's consideration of applications for plat approval, the standards set forth in this Article shall be considered minimum requirements.

Section 405.140 through Section 405.170. (Reserved)

Section 405.180 Utility Easement.

[R.O. 2008 § 405.180; Ord. No. 6496, 9-13-2018; Ord. No. 7056, 10-26-2023]

A. Utility Easement Requirements.

1. Utility Easements. Utility easements shall be provided and be at least ten (10) feet wide [five (5) feet on each side of the lot line] along rear, front and side lot lines. Easements of adequate width shall be provided for open drainage channels and rear yard swales, where required. Easements five (5) feet in width may be allowed for underground cable installations. Telephone and electric power lines shall be located underground, except in large lot subdivisions where all of the lots are twenty-two thousand (22,000) square feet or larger in size, and then the developer will have the option of underground or overhead utility lines.

2. Utility/Roadway Easements. A minimum of a ten-foot utility/roadway easement shall be required adjacent to all City, County and State rights-of-way. Such utility/roadway easements shall also include working space to work on such utility and/or roadway.

3. All underground public utility installations, including lines for streetlighting systems, which traverse privately owned property, shall be protected by easements granted by the developer to the appropriate public utility and reasonably approved by the public utility. Such easements shall be so located as to not interfere with the use of any lot or other part of the subdivision. The size of, and restrictions pertaining to, such easements shall be in accordance with the legally adopted or reasonable standards and the specifications of the agency having jurisdiction over the utility lines and subdivision and shall be indicated on the record plat submitted for approval.

4. Where a cut or fill for a street extends beyond the limits of the right-of-way, the developer shall provide a slope easement as determined by the City Engineer and/or his/her designee to be of sufficient area and limits to permit the construction and maintenance of the slope.

5. Stormwater easements and drainage rights-of-way may be required by the City of O'Fallon if necessary for proper drainage within or through a subdivision. Whenever a stream or surface drainage course conveying a minimum of one and one-half (1.5) cfs in a fifteen-year, twenty-minute storm is located in or planned for an area proposed for a subdivision, the developer shall provide a minimum ten-foot-wide easement or wider as determined by the City Engineer and/or his/her designee to be adequate in area to contain facilities, to control flooding or erosion along said stream or surface drainage course and protect the facility from blockages. Said easements shall be shown on the record plat with the following language: This easement is for emergency or access purposes; however, regular yard maintenance would fall on the property owner.

B. Off-Site Utility Easement.

1. For any existing off-site utility easements that are dedicated to the City of O'Fallon but are desired to be utilized by a new development, the following are required:

a. Only public-type facilities (mains that will be maintained by the public utility) can be placed within these easements. No private service lines or laterals can utilize these easements, unless otherwise approved by the City Engineer or their designee.

b. The owners of the property where the existing off-site easements reside should be notified in writing and at a minimum of forty-eight (48) hours in advance of the anticipated work, of any impacts to that property (either physical alterations of the property or losses of some service of the property). Any concerns shall be addressed with the property owner. Failure to reasonably restore the property to its prior condition may result in withholding of escrow releases or issuances of related permits until these issues are addressed. The Engineering Department shall be provided copies of any and all agreements, notifications and correspondences with the property owner prior to construction plan approval.

c. If the adjacent property owner is a common ground or private property (with no apparent off-site easements providing rights), then the developer of the project shall be required to obtain new off-site easements prior to plan and/or permit approval.

d. The City is not responsible for the acquisition of these off-site easements.

Section 405.185 Side Yard Easements.

[Ord. No. 7056, 10-26-2023]

A. Side Yard Easement Requirements.

1. Side Yard Easements For Utilities. Wider side yard easements, beyond the minimum typical lot side yard easements, shall be provided when certain utilities are to be installed along side yards. Utilities shall be limited to any public sanitary sewer main, water main, or storm sewer. Easements totaling fifteen (15) feet in total width shall be placed between houses, in lieu of the default side yard easements.

a. Extended Foundation. An extended foundation will be required when any of the said utilities are installed along the side yard. Foundations will be extended such that the foundation is outside of the 1:1 shear plan along the utility.

2. Side Yard Easements for Emergency Relief Swales. Wider side yard easements, beyond the minimum typical lot side yard easements, shall be provided when emergency relief swales are to be installed along side yards. Easements shall commence at the right-of-way line and continue until another swale takes over or a storm structure intercepts the swale. Easements totaling fifteen (15) feet in total width shall be placed between houses, in lieu of the default side yard easements.

Section 405.190 (Reserved)

Section 405.200 Street Name Signs And Street Names.

[R.O. 2008 § 405.200; Ord. No. 6496, 9-13-2018]

A. Street name signs meeting the requirements of the City of O'Fallon shall be erected by the subdivider at all intersections.

B. Stop signs, yield signs, etc., non-illuminated, non-electric, reflectorized shall conform to the current Manual on Uniform Traffic Control Devices and be provided by the developer as determined by the City of O'Fallon.

C. Whenever a new street is constructed along the approximate alignment or extension of an existing street, its name shall be the same as that of the existing one.

D. Whenever a cul-de-sac street serves not more than three (3) lots, the name of the intersecting street shall apply to the cul-de-sac.

E. To avoid duplication and confusion, the proposed names of all streets shall be approved by St. Charles County prior to preliminary plat approval and such names being assigned or used.

Section 405.210 Construction Requirements.

[R.O. 2008 § 405.210; Ord. No. 6496, 9-13-2018; Ord. No. 6855, 12-16-2021; Ord. No. 7056, 10-26-2023]

A. Public Street Construction. Streets shall be graded to full width of the right-of-way and fully constructed of asphaltic concrete or Portland cement concrete pavements in accordance with the St. Louis County Department of Transportation Standard Drawings, latest revision, and the St. Louis County Standard Specifications for Highway Construction, Divisions 200 through 1000, latest revision, except as modified by the City of O'Fallon's codes or ordinances.

1. Those publications listed above shall be adopted in whole with the following exceptions:

a. Standard drawing numbers: C203.66-C203.70, C604, C614, and C725-C732 drawings are not adopted.

b. All references to "St. Louis County" in any form shall be replaced with "City of O'Fallon" where appropriate.

c. All references to "department" shall mean the "Department of Engineering of the City of O'Fallon" where appropriate.

d. The standard details for construction of pavements shall follow those standards established by the ordinances of the City. The ordinances of the City of O'Fallon supersede and take precedence over the St. Louis County Standard Specifications for Highway Construction and standard details.

e. Construction Staking. All construction staking shall be provided by the contractor unless otherwise indicated by the City Engineer.

2. The following additional modifications shall be included and prevail over the adopted publications:

a. All concrete used for public infrastructure (streets, sidewalks, trails and curbs) in the City of O'Fallon shall be approved by the Eastern Missouri Pavement Consortium (EMPC) and meet requirements specified in City Ordinance No. 6335[1] approved on April 13, 2017. This includes roadways that are being developed and intended to become public roadways upon dedication and acceptance by the City.

[1] Editor's Note: Ord. No. 6335 was repealed and replaced September 13, 2018, by Ord. No. 6496.

b. Per City Ordinance No. 6335[2] approved on April 13, 2017, underdrains shall be required and installed per Exhibit A in Appendix D[3] of the O'Fallon City Municipal Code [Section 405.390(A)(5)]. Underdrains are required to be installed at all inlets. If a roadway has an open-type drainage system, underdrains are to be installed every five hundred (500) feet.

[2] Editor's Note: Ord. No. 6335 was repealed and replaced September 13, 2018, by Ord. No. 6496.

[3] Editor's Note: Appendix D is included as an attachment to this Chapter.

c. A representative sample of proposed limestone, calcitic dolomite or other mineral referred to as "limestone" that is used for coarse aggregate for concrete shall undergo appropriate testing, by an independent third-party testing agency to determine and verify that the coarse aggregate to be utilized does not exhibit, and is not susceptible to, alkali-carbonate reaction (ACR). Said third-party testing agency or agencies will need to be a City-approved agency that is experienced in performing the necessary tests.

d. For ACR testing, the testing performed shall include ASTM C295, ASTM C586 and ASTM C1105. The agency performing these tests must be informed prior to testing to look specifically for the potential of ACR, and the reports generated from the testing shall specifically address the potential of ACR in the text. This testing shall be performed for each ledge within a quarry that is planned to be used for concrete pavement within the City of O'Fallon.

e. The following requirements pertain to the ASTM C295 test. For the first two (2) years of this requirement, the tests shall be made within six (6) months of the planned use in concrete. After the first two (2) years of testing within a quarry, the City Engineer may allow the interval between tests to go up to one (1) year if there is convincing evidence to show this is warranted. The petrograph test shall be performed by a petrographer experienced in identifying ACR-prone dolomitic limestone or calcitic dolomite. The reports of the testing noted herein shall be submitted to the City with the concrete mix design submittal.

f. The following requirements pertain to the ASTM C586 and ASTM C1105 tests. These test reports shall be required to be submitted to the City beginning on August 1, 2017. The period of time from approval of this Chapter to when the reporting is required to be submitted allows time for the tests to be completed. For the first two (2) years of this requirement being in place, these tests shall be made within twelve (12) months of the planned use in concrete pavement. After the first three (3) years of testing within a quarry, the City Engineer may allow the interval between tests to go up to two (2) years if there is convincing evidence to show this is warranted.

g. In lieu of performing the above testing, Meramec gravel can be utilized for coarse aggregate in Portland cement concrete pavement. The coarse aggregate shall be Meramec gravel meeting Missouri Department of Transportation current "Missouri Standard Specifications for Highway Construction," Section 100.5.1.5, Gradation "D."

h. All coarse and fine aggregate material utilized for Portland cement concrete pavement shall have been inspected and approved by the Missouri Department of Transportation (MoDOT) for said use. If MoDOT inspection is not available, a third-party testing agency that is experienced in performing the necessary test will need to be approved by the City. The delivery ticket shall be marked to indicate that the rock has been tested and meets MoDOT specifications.

i. Coarse aggregate utilized for Portland cement concrete pavement shall only be used from rock ledges that have been inspected and accepted by MoDOT for said use. If MoDOT inspection is not available, a third-party testing agency that is experienced in performing the necessary test will need to be approved by the City.

j. A complete copy of the results of the above-referenced testing, as well as mix design submittal information, MoDOT certifications and other associated certifications required per this Chapter and per the St. Louis County Standard Specifications for Road and Bridge Construction shall be submitted to the City a minimum of seven (7) days prior to the placement of the concrete. The City must be in agreement with said test results, mix designs and certifications prior to the placement of any concrete.

k. For all granular base material deliveries, the delivery ticket must be annotated or signed by the rock supplier to indicate that the granular base material meets the Missouri Department of Transportation (MoDOT) requirements for Type 5 aggregate for base. This ticket must be submitted to the City for recordkeeping purposes at the time of delivery. Any deliveries made without the proper delivery tickets, including signature, will not be accepted for use. In lieu of a signature on the delivery ticket a separate product certification sheet with a signature of the company's quality control manager may be provided to go with the delivery tickets. The product certification sheet must be current, dated to within four (4) weeks of the date of delivery and also list the project name or job site location.

3. The minimum concrete pavement thickness shall be seven (7) inches thick. On minor residential streets, the transverse joints are not required to have load transfer devices. All other higher classifications of streets will be required to have load transfer devices in the transverse joints.

4. The following is a list of deficiencies that shall require concrete removal and replacement:

a. More than one (1) crack in a slab shall require a full slab replacement. However, if there is one (1) crack in the slab and there is deflection in the crack or other structural concern, then the full slab shall be replaced.

B. Approval Of Subgrade And Base (Subbase). The City Engineer and/or his/her designee shall approve the subgrade before any base is placed thereon and shall approve the base before concrete or surface course is placed. The subgrade and base shall be so constructed that it will be uniform in density throughout.

1. All subbase shall conform to a modified MoDOT Type 5 base [five (5) inches thick] and/or as approved by the EMPC. The modified MoDOT Type 5 rock shall meet all the requirements of MoDOT Type 5 rock and also be required to have no more than ten percent (10%) fines passing a No. 200 sieve. All gradations for this type of rock shall be submitted to the City and/or the EMPC for approval prior to use.

2. In all fill areas in the roadways, soil tests shall be submitted and approved by the City Engineer for each foot of fill and at least one (1) test and an average of one (1) test within every two hundred fifty (250) feet.

3. No traffic will be allowed on new concrete pavement until it has cured for seven (7) days and it reaches three thousand five hundred (3,500) psi. Concrete pavement shall not be approved unless it reaches required strength within twenty-eight (28) days.

4. Prior to placement of aggregate base material on subgrade and prior to placement of pavement on base material, the subgrade and base must be proof-rolled with a fully loaded (ten-ton load) tandem truck or equivalent tire vehicle with one (1) pass down each driving lane no faster than three (3) miles per hour. If soft spots are detected, or pumping, rutting or heaving occurs greater than one (1) inch at the subgrade, the roadbed shall be considered unsatisfactory, and the soil in these areas shall be remediated to the depth indicated by the contractor's testing firm and approved by a representative of the City Engineer.

5. Subgrade and base beneath pavements shall be compacted to St. Louis County Standard Specifications for Road and Bridge Construction. The moisture range shall be determined by the Standard or Modified Proctor Density Method AASHTO T-99 and within -2)/+4 percentage points of the optimum moisture content.

6. The entire width and length will conform to line, grade and cross section shown on the plans or as established by the engineer. If any settling or washing occurs, or where hauling results in ruts or other objectionable irregularities, the contractor shall improve the subgrade or base to the satisfaction of the City before the pavement is placed. Additional rolling or methods to verify compaction shall be at the discretion of the City Engineer. Tolerance allowed on all lines, grades and cross sections shall be plus or minus four-one-hundredths (+ 0.04) feet.

7. Delivery tickets for all granular base material shall be submitted to the City as specified in City Ordinance No. 6335[4] approved on April 13, 2017.

[4] Editor's Note: Ord. No. 6335 was repealed and replaced September 13, 2018, by Ord. No. 6496.

C. Utility Work Prior To Base Construction. No base course work may proceed on any street until all utility excavations (storm and sanitary sewers, water, gas, electric, etc.) have been properly backfilled with granular material, crushed stone or gravel mechanically tamped in ten-inch lifts. Utilities installed after subgrade preparation shall be bored. Compaction requirements shall follow St. Louis County standards.

D. Outside (beyond) the pavement limits, excavations shall be jetted with water and allowed to set for a length of time satisfactory to the City Engineer.

1. Jetting. Granular materials and earth materials associated with new construction beyond the pavement may be jetted, taking care to avoid damage to newly laid sewers. The jetting shall be performed with a probe route on not greater than seven-and-one-half-foot centers with the jetting probe centered over and parallel with the direction of the pipe. Trench widths greater than ten (10) feet will require multiple probes every seven-and-one-half-foot centers.

a. Depth. Trench backfill less than eight (8) feet in depth shall be probed to a depth extending to half the depth of the trench backfill, but not less than three (3) feet. Trench backfill greater than eight (8) feet in depth shall be probed to half the depth of the trench backfill but not greater than eight (8) feet.

b. Equipment. The jetting probe shall be a metal pipe with an exterior diameter of one and one-half (1.5) to two (2) inches.

c. Method. Jetting shall be performed from the low surface topographic point and proceed toward the high point, and from the bottom of the trench backfill towards the surface. The flooding of each jetting probe shall be started slowly allowing slow saturation of the soil. Water is not allowed to flow away from the ditch without first saturating the trench.

d. Surface Bridging. The contractor shall identify the locations of the surface bridging (the tendency for the upper backfill crust to arch over the trench rather than collapse and consolidate during the jetting process). The contractor shall break down the bridged areas using an appropriate method such as wheels or bucket of a backhoe. When the surface crust is collapsed, the void shall be backfilled with the same material used as trench backfill and rejetted. Compaction of the materials within the sunken/jetted area shall be compacted such that no further surface subsidence occurs.

E. Required Joint Details In Concrete Streets. Construction joints shall be required in all concrete roadways as a normal requirement. St. Louis County Department of Transportation standards shall apply. Additionally:

1. The developer's engineer shall identify on the record plat any lot for which special precautions should be taken to prevent damage to any structure caused by the forces commonly known as "street creep." The developer's engineer shall also recommend any special construction technique required to counter the forces.

F. Material Testing And Frequency. Materials for construction shall be tested and inspected per the appropriate ASTM code or at the City Engineer's discretion. The developer's engineer shall perform the following quality control guidelines:

1. Concrete.

a. Cylinders/Compressive Strength. One (1) set of four (4) cylinders within the first fifty (50) cubic yards and one (1) set per one hundred (100) cubic yards thereafter. One (1) cylinder must be tested at seven (7) days, one (1) at fourteen (14) days and two (2) at twenty-eight (28) days. If the first cylinder does not meet specifications at twenty-eight (28) days, then the second cylinder must be held and tested at day fifty-six (56).

b. Percent Air And Temperature. First truck batch each day and two (2) thereafter until a consistency is encountered. Once a consistency is encountered, then tests will be performed in conjunction with the concrete cylinders.

c. Slump. First truck batch each day and two (2) thereafter until a consistency is encountered. Once a consistency is encountered, then tests will be performed in conjunction with the concrete cylinders.

d. If concrete is batched from more than one (1) plant, then the aforementioned guidelines will be applicable to each plant.

2. Subgrade And Base.

a. Proof roll as described in Section 405.210(B).

b. One (1) compaction test per two hundred fifty (250) feet of mainline paving, three (3) tests per intersection, five (5) tests within culs-de-sac and one (1) test per repair slab.

c. Gradation test for subbase material.

3. Asphalt.

a. One (1) set of compaction tests per two hundred fifty (250) feet of mainline. One (1) set includes three (3) tests across the paved lane at the same station.

b. One (1) bulk density test per paving operation.

4. Site Grading.

a. Within City Right-Of-Way. Material is to be placed in eight-inch to twelve-inch loose lifts and compacted per the approved compaction requirements. One (1) compaction test will be performed every two hundred fifty (250) feet along the center line for each lift.

b. Outside Of City Right-Of-Way. Material is to be placed in eight-inch to twelve-inch loose lifts and compacted per the approved compaction requirements. One (1) compaction test will be performed at two-foot vertical intervals and approximately every one thousand (1,000) cubic yards.

5. Quality Control Reports.

a. Daily. Descriptive daily reports are required for each day a representative is present on-site from the quality control company (soil testing firm). At a minimum, the daily report should include representative on-site, date, materials observed, activities performed, weather, recommendations or concerns made and to whom.

b. Proctor Reports. Must have a valid Proctor value prior to testing on-site. At a minimum, the Proctor curve provided must include sample location and must have five (5) density points (values) and moisture (values) listed on the document, optimum moisture content, maximum dry density, zero air voids curve and assumed specific gravity, natural moisture content, Proctor type and procedure, liquid limit, plastic limit.

c. Compaction Report. At a minimum, the compaction reports will include elevation of test and rod depth, station/specific location, Proctor type, optimum moisture content, maximum lab dry density, in place moisture content, in place dry density, percent compaction, does/does not comply with specification requirements, specification requirements, material type, weather, date. If a drawing is needed to show location of the tests, the drawing must be professionally done or at least on sheet copy of the plans. No hand drawings will be accepted.

d. Concrete Report. At a minimum, the field concrete report will include location of concrete placed, representative on-site, date, weather, concrete supplier, ticket and truck number, time truck arrived on-site, time concrete poured, air temperature, concrete temperature, mix type, strength requirement, water added, slump (actual and required), air content (actual and required), number of cylinders cast, overnight temperature, overnight storage temperature, date received at lab. At a minimum, the laboratory concrete field report will include age (days) of test, test date, cylinder diameter, cylinder area, load (pounds), compressive strength (psi), does/does not comply with specification requirements.

6. Equipment Calibration. The developer's contractors and subcontractors must have their equipment calibrated by the following minimum standards:

a. Air meter: weekly.

b. Cylinder compression: annually by independent calibration service.

c. Batch scales: monthly.

d. Nuclear testing devices: every six (6) months.

e. Proctor equipment: every six (6) months.

f. Slump cone: monthly.

G. Specifications For Construction Of Driveway Entrances. All driveway entrances constructed within the public right-of-way in the City of O'Fallon shall meet the following specifications and conform to site plan requirements. A permit shall be obtained through the Engineering Department, for any driveway widening and/or modifications to the driveway apron, within the City street right-of-way. A permit will not be needed if the construction is part of another City-permitted development:

1. All driveway entrances shall be built to grade;

2. The maximum grade of the driveway, behind the sidewalk, shall be fifteen percent (15%). No portion of the driveway may exceed fifteen percent (15%) in slope.

3. If a culvert is necessary in the opinion of the Engineering Department, no culvert smaller than twelve (12) inches in diameter shall be installed, and no culvert shorter than sixteen (16) feet shall be installed; a larger culvert shall be installed wherever, in the opinion of the Engineering Department, it is necessary.

4. No driveway entrances shall be constructed or built or partially constructed or built within two (2) feet from the side or rear property lines. No driveway shall be closer than six (6) feet from the edge of a curb inlet.

Exceptions:

a. Existing entrances that are already closer than two (2) feet from the property line.

b. Multi-family dwellings.

c. City staff may allow minor alterations in special circumstances.

5. All driveway entrances shall be six (6) inches in depth for residential driveways and a minimum of seven (7) inches in depth for commercial driveways from the edge of the road pavement to the property line.

a. For commercial driveways, for new concrete entrances at existing pavement and curbing, saw cut at one (1) foot and install tie bars, five-eighths-inch diameter, eighteen (18) inches long, at twelve-inch centers along all saw-cut edges. New tie bars shall be placed in drilled holes with non-shrink grout or epoxy. The bars, where existing, shall be cleaned and straightened for incorporation in the new concrete.

b. For commercial driveways, the new driveway edge up against existing street pavement shall match the street pavement thickness. All street pavement removed and replaced shall be the same thickness. After the gutter line or the edge of street pavement line, it shall then flare back to the seven-inch minimum depth within a two-foot length.

6. All driveway approaches constructed in conjunction with a sidewalk shall give the appearance that the sidewalk is continuous. That portion of the driveway approach that doubles as a sidewalk shall have a one-and-one-half percent (1.5%) maximum cross slope the same as the abutting sidewalk, meeting ADA requirements.

a. If the existing sidewalk adjacent to the driveway is over one and one-half percent (1.5%) in cross slope, then the first panel of sidewalk immediately adjacent to the driveway shall be removed and replaced as a transition section.

b. An exception to this requirement is when a sidewalk does not exist nor is not planned to be built.

7. Expansion joints in the driveway approach area shall be two (2) inches wide and full depth at the back of curb. In all cases if the driveway approach depth exceeds the minimum six-inch thickness, the joint material shall extend the full depth of pavement, no concrete to concrete interface.

8. The expansion joint between the driveway and garage floor shall be a minimum of two (2) inches and full depth of slab.

H. Guardrail. The following additional modifications shall be included and prevail over the adopted publications:

1. Guardrail shall be required to protect traffic from hazardous features, or to restrict or prohibit traffic movements. Guardrail will be required for roadway heights (including fill) of ten (10) feet or more adjacent to the roadway, or heights of seven (7) feet or more at pavement terminations. Terminal sections will be required for both directions of traffic flow on two-way pavement. Where the distance between terminal sections of two sections of guardrail will be one hundred (100) feet or less, one (1) continuous length of guardrail shall be installed.

a. Guardrail shall be provided for protection of traffic adjacent to creeks and lakes, at bridge ends, piers, large signs (with no breakaway base) and headwalls, and as street barricades, as directed by the Engineering Department. Refer to the St. Louis County Standard Drawings C606.01 through C606.23.

2. Roadway Berms. The grading and placement of berms within the road right-of-way as an alternate to guardrail may be permitted with special approval by the Engineering Department where such installations are considered compatible with the roadway typical section. Berms shall be constructed to a height of three (3) feet above the adjacent edge of pavement or curbs with 3:1 side slopes.

3. Escape Area. The grading of an escape area as an alternate to guardrail or roadway berms will have a slope no steeper than 6:1 and will be permitted by the Engineering Department in accordance with the following:

Minimum Escape Area Distance
Design Speed (MPH)	From Edge of Pavement to Breakpoint (feet)
25	20
30 to 35	25
40	30

Section 405.220 Monuments Required.

[R.O. 2008 § 405.220; Ord. No. 6496, 9-13-2018]

A. As part of public street construction, sufficient permanent and distinguished monuments shall be accurately placed throughout the subdivision so that street alignment may be traced with accuracy. Such monuments shall be in the form of iron pins not less than one-half (1/2) inch in diameter and three (3) feet long driven into the earth, or spikes not less than six (6) inches long driven into the pavement, or of something equal. Such monuments shall be installed by the subdivider as soon as reasonably possible. The location of such monuments shall be indicated on the final plat and shall be placed in accordance with the following requirements:

1. Street Points. Monuments shall be set at the intersection of all streets and the beginning and end of all curves along street center lines.

2. Curb Marks. Curbs shall be permanently marked at the beginning and end of all curves and at the prolongation of all lot side lines.

Section 405.230 Public Storm Sewers And Other Drainage Appurtenances.

[R.O. 2008 § 405.230; Ord. No. 6496, 9-13-2018; Ord. No. 7056, 10-26-2023]

A. In addition to the installation of curbs or gutters along the streets as required by this Chapter, storm sewers shall be required. Such systems will be equipped with adequate basins, inlets and outlets and shall be constructed in accordance with the applicable provisions in the specifications. The stormwater drainage system shall be separate and independent of the sanitary sewer system. The plans and specifications for the disposing of stormwater shall be approved by the City Engineer and/or his/her designee.

B. General. All construction details and specifications pertaining to stormwater drainage shall be in accordance with the Metropolitan St. Louis Sewer District (MSD) Standard Construction Specifications for Sewers and Drainage Facilities, latest version, and the City of O'Fallon's requirements, unless otherwise noted herein. A registered engineer's seal is required on all drainage plans submitted for approval.

C. Design Criteria. Unless otherwise specified below or in other City of O'Fallon requirements, all engineering design shall adhere to the Metropolitan St. Louis Sewer District (MSD) Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and Stormwater Drainage Facilities, latest revision.

1. Chapter 5 (Flood Plain Requirements) is not being adopted. For all floodplain requirements, see Chapter 415 of the City Code.[1]

[1] Editor's Note: See Ch. 415, Flood Hazard Prevention Code.

2. All references to "District" in any form shall be replaced with "City of O'Fallon" where appropriate.

3. All stormwater design is to be by the Rational Method, except that in certain large developments, the use of other methods of analysis such as the Unit Hydrograph will be considered for stormwater design. However, prior approval must be obtained from the City Engineer and/or his/her designee at the preliminary design stage, where use of the Unit Hydrograph or other methods of analysis are requested.

4. Runoff factors shall be per the MSD requirements.

D. Drainage Structures. All structures shall be designed for HS20-44 loading.

1. Bridges. Bridges shall be designed for the 100-year storm frequency and provide two (2) feet of freeboard between the bottom of superstructure and highwater elevations.

2. Culverts.

a. Crossroad culverts, not at low points, shall be designed on a storm frequency of fifteen (15) years with entrance control and two (2) feet of freeboard at the shoulder line.

b. Culverts, at or near low points in floodplains, shall be designed on a storm frequency of one hundred (100) years with entrance control and two (2) feet of freeboard at the shoulder line.

c. Culverts, at or near low points not in floodplains, shall be designed on a storm frequency of fifty (50) years with entrance control and two (2) feet of freeboard at the shoulder line.

3. Roadways. Whenever a watercourse is proposed or exists within proximity of and is approximately parallel to an existing or proposed roadway, the low shoulder elevation of the roadway shall be established from the highwater elevation with one (1) foot of freeboard in non-floodplain areas and two (2) feet of freeboard in floodplain areas.

4. Street Inlets. In certain cases, where steep grades or other unusual conditions are encountered, a grated trough may be required in lieu of multiple inlet structures upstream in order to eliminate excessive bypass.

5. Pipes.

a. Pipes within the public right-of-way or easement shall be reinforced concrete pipe (RCP) ASTM C-76, Class III, and a minimum of twelve (12) inches diameter. Design calculations may be submitted allowing a lower class of RCP.

b. The use of high-density polyethylene (HDPE) shall not be allowed.

c. The use of polypropylene (PP) shall not be allowed.

d. The use of corrugated steel pipe should only be considered when all options for reinforced concrete pipe are deemed not feasible. Corrugated steel shall be M-36, minimum sixteen-gauge asphalt polymer, or aluminized coating, a minimum of eighteen (18) CSP, will be allowed with these conditions. This pipe material may be used for private driveway culverts or private road culverts, as the maintenance shall be with the property owner, even though the pipe is in the right-of-way.

e. Additional general pipe requirements.

(1) The City Engineer and/or his/her designee shall review the proposed project for suitability.

(2) Standard concrete drainage structures and flared end sections will be used in the installation process.

(3) Installation shall be in accordance with ASTM D-2321 and/or manufacturer's recommendation, whichever is more stringent.

f. The required stormwater hydraulics shall be submitted with all types of pipes.

g. Pipe reduction will not be allowed.

h. In situations where storm pipe cover is less than three (3) feet, calculations will be required to determine the class or gauge of pipe.

i. All new concrete pipe shall be installed with O-ring rubber-type gaskets per MSD Standard Construction Specifications. Connections at all existing structures are to be made with rubber, watertight A-lock joints or approved equals, as determined in the preconstruction meeting or prior to construction. Broken and/or unsuitable connections shall be removed and replaced.

j. Pipes normally should be sized using the partial flow design; however, under special circumstances, full flow design will be allowed, provided hydraulic grade line information is shown indicating adequate freeboard. This additional information will be supplied for the fifteen-year and 100-year storms.

k. Freeboard requirements will be two (2) feet from the inlet sill or manhole top.

l. Starting Hydraulic Grade Line.

(1) If a pipe run drains into a detention basin, then the starting hydraulic grade shall be calculated for both the fifteen-year routed and the 100-year low-flow blocked highwater elevations of the basin. Freeboard requirements only apply to the fifteen-year calculations, however for the 100-year calculations, all of the water must remain within the structure.

(2) If a pipe run drains into a naturally occuring creek, then the starting hydraulic grade shall be calculated from the hydraulic model of the creek for the 100-year highwater elevations of the creek. For studied creeks, use the effective Flood Insurance Study published by FEMA for that specific creek. For unstudied creeks, use the MSD method of determining the 100-year highwater elevations of the creek.

m. If existing storm sewers are located near a proposed development, where proposed storm sewers are planned, then they shall all be connected, at the direction of the City Engineer. No new flared-end pipe sections shall be allowed to be placed within one hundred (100) feet of an existing flared-end pipe section, nor will a rip-rap area connection between pipes be allowed to be installed, unless the discharge separately into a creek. Instead, an enclosed connection shall be made between the two (2) pipe sections, the existing flared-end section shall be removed, area inlets or other means of drainage capture shall be installed as required, and the area shall be covered and regraded as needed to ensure that proper drainage for the area continues unabated. The developer responsible for the new connection shall be responsible for obtaining all required easements, performing piping installation, performing grading operations and any/all other work necessary to achieve this connection.

E. Plans And Calculations.

1. General. Plans shall be any scale from one (1) inch equals ten (10) feet through one (1) inch equals one hundred (100) feet so long as the scale is an increment of ten (10) feet. Plans shall be prepared on exhibits nominally twenty-four (24) inches by thirty-six (36) inches. All calculations submitted shall be in accordance with Section 405.100 and shall include the following information:

a. Site Drainage Map. A drainage map is required and should be developed from a base reproduction of the site plan or grading plan. Plans and calculation shall be prepared in accordance to the checklist pertinent for the type of development (See Title IV Notes: Notes and Appendixes, Appendix C[2] for application and checklist for compliance with this Section).

[2] Editor's Note: Appendix C is on file in the City offices.

b. Supplemental Drainage Map. A supplemental map may be required and should be developed from a portion of U.S.G.S. Quadrangie Map. This map must include the site boundary and the watershed tributary to the project area.

c. Surface Drainage. The following information shall be provided by the developer:

(1) No sheet flow over one (1) cfs will be allowed over terraces with slopes that are and/or greater than five (5) feet in height. Berms and/or swales shall be provided to collect the flow at the top of the terrace and carry it to a drainage structure. Total accumulation inside berm and/or swales shall be a maximum of three (3) cubic feet per second.

(2) Excluding existing creeks and swales not being modified by the proposed development, the developer's engineer shall provide critical cross sections, profiles and hydraulic computations for ditches and swales with flows in excess of one (1) cfs and creeks with flows in excess of three (3) cfs.

(3) Overland Flow Swale. All emergency/overland flow swales shall be designed on the plans. At all low points on streets, the flow-line elevation of the swale at the right-of-way line shall not exceed eight (8) inches higher than the top of the curb inlet (at said low point). The alternative to this depth is to install a larger storm pipe, capable of handling the 100-year, twenty-minute storm.

d. Location Of Drainage Structures. The lateral location of all drainage structures shall be shown by street center line stationing and perpendicular offset distance, and in large lot subdivisions, by referencing to rear lot line, in addition to the following requirements:

(1) Inlets shall be appropriately sized and spaced, taking into consideration by pass, depth of flow and width of spread of flow in gutters.

(2) For inlets in vertical sag curves, the center of the main chambers shall be placed within one (1) foot of the exact mathematical low point.

(3) All manholes shall be located outside of the proposed roadway pavements.

(4) Inlets shall be located as follows:

(a) Sump design shall be in accordance to the City of O'Fallon's adopted street standards.

(b) Location of area inlets in roadway ditches shall be compatible with ultimate improvements at an elevation compatible with the shoulders and sidewalks.

(c) No driveway shall be closer than six (6) feet from the edge of a curb inlet.

Section 405.240 Stormwater Detention.

[R.O. 2008 § 405.240; Ord. No. 6496, 9-13-2018; 7-27-2023 by Ord. No. 7034; Ord. No. 7056, 10-26-2023; Ord. No. 7138, 9-26-2024]

A. Policy. It is the policy of the City of O'Fallon to protect and promote the public health, safety and general welfare. The criteria for stormwater detention will:

1. Reduce the possibility of damage to public and private property;

2. Reduce the erosion of land and creek channels;

3. Assist in the attainment and maintenance of water quality standards; and

4. Preserve and enhance the environmental quality of the watercourses in the City. This criteria provides uniform procedures for designing and checking the design of storm drainage detention systems.

B. General Guidelines.

1. Applicability. This Section shall apply to all development within the corporate limits of the City of O'Fallon, Missouri. Residential developments having a total area of less than five (5) acres and commercial or industrial developments having a total area of less than one (1) acre may be given a waiver by the City in accordance with Article V of this Chapter subject to the following conditions:

a. The City retains the right to require detention storage in all cases in which the proposed development will generate excess runoff that adversely affects the carrying capacity of the receiving watercourse.

b. Developments less than one (1) acre with less than thirty percent (30%) of the area paved and developments generating less than one (1) cubic foot per second per acre (cfs/acre) increased runoff shall not be required to provide detention storage unless the condition in Subsection (B)(1)(a) above is applicable.

c. This Section shall apply for all newly platted areas and new developments proposed after August 17, 1987. All developments that have an approved preliminary plan by the Planning and Zoning Commission at the time of the approval of this Section will not have to conform to this Section.

2. Affidavit Of Disclosure Of Property Interest. The effective acreage for a site is not limited to a fractional part of the total. If a project is developed in phases or small plats, the total acreage of the project site must be considered. At the time the owner of any development submits a preliminary plat or preliminary plan, the owner shall also identify to the City all contiguous property or property in the watershed that he/she has interest in.

3. Method Of Evaluation. The storage capacity and discharge rate shall be based upon the calculated volume and peak flow of the stormwater runoff, respectively. The calculations for sites having an area of one hundred (100) acres or less shall be made using either the Soil Conservation Service Method or the Rational Method. If the site is larger than one hundred (100) acres, then the engineer shall use the Soil Conservation Service Method. If another method is desired to be used, the engineer shall submit a proposed method of evaluation for the calculations for review and approval. The permitted discharge rate of stormwater runoff shall be determined by calculating the rate of runoff for the site's pre- and post-development conditions. The engineer shall determine the most critical storm looking at three (3) different time periods:

a. The time of concentration;

b. A one-hour storm; and

c. A twenty-four-hour storm.

4. Detention Of Differential Runoff. All new developments shall provide a stormwater detention facility that insures that the rate of flow of stormwater runoff discharge from the site after development for a two-year, fifteen-year, and 100-year (twenty-minute storm), unless given a waiver by the City in accordance with Article V of this Chapter. Data shall be submitted for the two-, fifteen-, and 100-year frequency (twenty-minute storms).

a. The highwater elevations for all of the above-mentioned storm events shall be provided on the plans.

b. The maximum ponding elevation shall be calculated based on a routing of the design storm (100-year, twenty-minute) assuming the lowest outlet is blocked with the water ponded to its maximum elevation. A minimum of one (1) foot of freeboard shall be provided from the top of the basin to the maximum ponding elevation.

c. Any existing development that was approved and accounted for detention under previous City codes, shall continue to maintain detention requirements that were applicable at the time, and those former requirements will continue to be allowed, even if the property use expands (for example, a building addition, a parking lot addition).

d. Any redevelopment of a tract of land shall have the current standards applied to the complete site.

e. Any undeveloped lot(s) within an existing development (residential or commercial) that is already covered with detention, under previous City requirements or as may have been accepted by the City with annexations, may continue being developed under the previous requirements, unless:

(1) If the previous requirements are not known or the existing detention facility calculations cannot to be verified, then the current detention requirements of the City shall govern for the improvements for the proposed lot.

(2) If the existing development does not have detention, then the current detention requirements of the City shall govern for the improvements for the proposed lot.

C. Design Criteria.

1. General Requirements. The design shall be accomplished under the direction of a Missouri registered professional engineer. The design shall also be based on land use in the tributary area as zoned, actually developed or indicated by an adopted future land use plan, whichever basis produces the greatest runoff.

2. Other References. Other agencies have criteria and regulations pertaining to drainage systems which may complement these criteria. When conflicts are encountered, the most rigorous criteria shall govern.

a. FEMA. Floodplain regulations and implementing ordinances adopted by municipalities. Drainage systems designed within the limits of the designated 100-year floodplain on the principal stream shall be designed to convey the flood as defined by applicable published floodplain information studies. For areas located in FIRM Zone "A" outside the detailed study, the developer shall prepare studies and calculations establishing the floodplain, elevation and width. These calculations shall be submitted to the reviewing agencies for approval.

(1) In the event that a developer desires to place a basin within an existing floodplain that is to be adjusted via a FEMA-approved process, then the following process must be followed:

(a) Developer shall identify the proposed conceptual new floodplain limits on the plans to be submitted to Planning and Zoning.

(b) Obtain conditional Letter of Map Change from FEMA prior to construction plan approval.

(c) Approved Letter of Map Change denoting the adjusted floodplain shall be completed prior to final ten percent (10%) escrow release for the development. This item will be noted as part of the construction inspection process.

b. Missouri Department Of Natural Resources. Rules and regulations of the Dam and Reservoir Safety Council shall apply to those Missouri structures classified as dams thereunder.

3. Stormwater Runoff. The design criteria used in determining the amount of runoff shall be the same as set out in Section 405.230 of this Chapter.

4. Hydraulic Considerations For Detention Storage.

a. Principal spillways shall be designed to meet the following requirements:

(1) The principal spillway shall be designed to function without requiring attendance or operation of any kind or requiring use of equipment or tools.

(2) All discharge from the detention facility when inflow is equal to or less than the 100-year inflow shall be via the principal spillway(s).

(3) The design shall allow for discharge of at least eighty percent (80%) of the detention storage volume within twenty-four (24) hours after the peak or center of mass of the inflow has entered the detention basin. On basins less than one hundred (100) acres, this shall not apply.

(4) The design discharge rate via the spillway shall continuously increase with increasing head and shall have hydraulic characteristics similar to weirs, orifices or pipes.

b. Emergency Spillways. The emergency spillway shall be provided to pass a 100-year storm without damaging any property and, where applicable, designed to DNR dam safety requirements. Overland flow route will be required to be depicted on the plan for emergency spillways.

c. Outlet Works. Detention facilities shall have an outlet works consisting of valves, gates, pipes and other devices as necessary to completely drain the facility in seventy-two (72) hours or less when required for maintenance or inspection on normally wet basins.

d. Sediment Storage. Public detention facilities shall be designed to provide for five (5) years of sediment accumulation calculated by using Figure 1 in Appendix D.[1] All other detention facilities shall provide storage for two (2) years of sediment accumulation by using Figure 1, except for those using roofs of buildings, paved parking areas or other facilities designed to preclude the deposition or accumulation of sediment. Sediment storage volume shall be in addition to the volume required for temporary storage of stormwater to properly size the detention facility on normally wet basins.

[1] Editor's Note: Appendix D is included as an attachment to this Chapter.

e. Erosion and Sediment Control. A SWPPP shall be developed to prevent erosion in principal spillways and prevent the flow or runoff of mud, silt, dirt, debris and other materials onto streets, sidewalks and other public rights-of-way, in accordance with the guidelines and requirements as set forth in Section 405.245 of the City Code. Special measures shall be taken by the developer to not permit sediment from filling the proposed detention basin during all construction of the proposed development unless a design is provided and approved to use the detention basin as a temporary silt basin until such time as the stormwater improvements are completed and the site vegetated.

f. Public Detention Facilities. As a general rule, detention facilities shall be private facilities. When determined that a facility shall be a public facility, the owner shall dedicate the detention facility and easements with the recording of the record plat, except:

(1) When multipurpose wet facilities are planned or are suitable for use for private aquatic recreation or for aesthetic enhancement of the owner's property.

(2) When multipurpose dry facilities incorporate surface recreational improvements.

(3) Any other means of dedication shall require acknowledgement and acceptance by ordinance from the City Council.

g. Private Detention Facilities. Shall be designed requiring the same criteria as the public detention facilities. The amount of easement shall be equal to the land occupied by the facility, plus a twenty (20) foot wide strip around the perimeter of the highest elevation attained by the design storage volume, plus an access easement twenty (20) feet in width between the facility and the public street. This easement shall be shown as common ground and be dedicated to the trustees of the subdivision or owner of the multi-family, commercial or industrial property for the purpose of maintenance of the stormwater detention facility and shall not be part of a residential lot. The easements as described above shall also be dedicated to the City for emergency access or periodic inspection. The following items shall be addressed:

(1) A plan for perpetual maintenance and designating responsibility for the maintenance shall be provided for its continuing performance to the standards established by these criteria.

(2) Underground detention facilities shall also have the above-mentioned easements provided. Easements shall be labeled properly on the record plat or by separate document.

h. Plan Requirements. The plan requirements shall be the same as set out in Section 405.230 of this Chapter with the following additions:

(1) Elevation-area-capacity curves for the detention facility, including notation of the storage volumes allocated to runoff and permanent residual water storage for other uses (wet basins only).

(2) Inflow hydrograph (detention volumes for Rational Method) for the two-, fifteen-, twenty-five-, and 100-year recurrence interval design storms.

(3) Stage-discharge rating curves for each spillway and for combined spillway discharges.

(4) Routing curves for the two (2) year and all greater criteria recurrence interval design storms with time plotted as the abscissa and the following plotted as ordinates (this item is not required for the Rational Method):

(a) Cumulative inflow volume.

(b) Cumulative discharge.

(c) Stage elevation.

(5) A ten (10) foot minimum depth for all retention (wet detention) basins shall be required (per DNR recommendation for healthy aquatic environment).

(a) Shallower depth [eight (8) foot minimum] may be allowed as long as aeration is provided on the pond.

(6) All storm sewer pipes shall be labeled as either "public" or "private" on the storm sewer profile sheets. The transition structure from public to private shall also be labeled accordingly. Pipes are not allowed to have said transition outside of a structure.

(7) For all underground detention facilities, a manhole (or similar accessible structure) shall be provided both upstream and downstream [within ten (10) feet or as approved by the City], for access. Access lids shall be labeled with the words "underground basin" or similar on each structure. Labels shall be cast into the lid and be of the same material that is required under storm sewer design.

(8) No planting of trees or extensive landscaping shall be permitted over the top of the underground detention facility, within the limits of the encompassing easement.

5. Safety Bench. All retention (wet detention) basins shall have a safety bench above the normal pool water elevation, with the following requirements:

a. Width shall be six (6) feet, starting at where the normal pool elevation intersects the bank.

b. Slope of the safety bench shall not exceed 6:1.

c. The 3:1 slope of the basin banks shall then start at the back of the safety bench.

d. Any aquatic bench (defined as a stormwater BMP) being considered shall be a separate entity from the safety bench.

D. Construction Alternates. The developer shall build as part of his/her development a detention facility as required by this Section unless the following Subsections apply:

1. If requested by the developer or by the City of O'Fallon, the City, at its option, may waive the construction of a detention facility as for the development. The developer shall seek approval from the City Engineer for the basin to be waived. If the waiver is granted, the developer shall pay an amount equal to the cost of detention for the site as determined by the unit cost as published and updated by St. Louis County. This money is to be used in a stormwater fund for future City stormwater projects. A contractor's bid may be submitted in lieu of using the published data although the bid must be reviewed and approved by the City Engineer prior to acceptance. This option may only be considered if the requirements set out in Subsection (B) above are applicable.

2. Off-Site/Regional Detention. All detention facilities shall be on the individual site being developed. The exception to this requirement is if there is either a regional detention facility identified that accounts for the subject property being developed, or if the subject property is a lot within a subdivision plat that accounts for detention. In any case, if the off-site or regional detention facility does not fully account for the City's requirements at the time of development, then supplemental detention may be needed.

a. On-site detention will be required whenever increased runoff from the proposed development creates a hazard downstream.

b. Supplemental detention may be provided by means of modifications to the off-site or regional basin if feasible. If it is not feasible, then supplemental detention on-site shall be provided.

c. If the off-site/regional detention facility is existing at the time of development, then the developer of the subject property shall provide approval for use of the detention facility (that also addresses maintenance responsibility) for said facility, prior to approval.

E. Inspection, Maintenance And Acceptance By The City Of O'Fallon.

1. The City Engineer and/or his/her designee shall inspect or cause to be inspected all stormwater detention facilities constructed within the City of O'Fallon, Missouri. Through such inspections the City Engineer and/or his/her designee shall ensure that the facilities under construction are being constructed in accordance with the approved plans for such development.

2. Each owner of the property being developed or has been developed, whose property has caused the increase in runoff that has necessitated the need for detention, has the responsibility and duty to properly operate and maintain any stormwater management system and/or detention facility, which has not been accepted for maintenance by the City. The responsibility of maintenance of the system and subdivision projects shall remain with the developer until such time as the stormwater management system escrow for such development has been released and turned over to the homeowner's association or property owner(s) of record. If there is no active homeowners' association, all properties listed as part of the subdivision and/or development will become responsible for maintenance. This will include all underground detention facilities.

3. Maintenance responsibility shall remain with the property owner(s) whose said property or development necessitated the need for detention. Regardless of ownership of said basin, should the developer, owner(s), association, or other entity responsible for maintenance choose to sell, abandon, or otherwise vacate their interest or ownership of the basin, this will in no way eliminate their maintenance responsibility of said basin unless they have provided for perpetual future maintenance separately. Said maintenance plan as referenced in Subsection (C)(4)(g)(1) above shall be submitted to the City for approval.

4. All such privately owned and maintained stormwater systems and/or detention facilities shall be subject to periodic inspections by the City Engineer and/or his/her designee. After an inspection by the City Engineer and/or his/her designee, he/she determines whether or not the conditions of the privately owned stormwater system and/or detention facilities are safe and operating and functioning per the approved plans.

a. For underground detention facilities, the owner(s) shall be required to submit an annual maintenance report to the City Engineer verifying its condition and that it is operating and functioning per the approved plans. Said inspection shall be performed by a competent professional who is experienced in this type of work.

5. If the privately owned stormwater systems and/or detention facility is found to be deficient and in need of compliance measures or maintenance, the property owner(s) will be notified and correction of such requested. Any corrections will be the responsibility as identified in Subsection (E)(3) above. Any cost incurred by the City, as a result of the City Engineer's actions, shall be assessed against the owner(s) of the system. Initially, the stormwater funds as set up in Subsection (D)(2) above may be used to pay for any such emergency authorized by the City.

6. After notification is provided to the owner(s) of any deficiencies discovered from an inspection of a privately owned stormwater system and/or detention facility, the owner(s) shall have thirty (30) days or other time frame mutually agreed to between the City and the owner(s) to correct the deficiencies. The City shall then conduct a subsequent inspection to ensure completion of the repairs. If repairs are not undertaken or not found to be done properly, then enforcement procedures following this Section shall be followed.

7. If, after inspection by the City, the condition of a privately owned stormwater system and/or detention facility presents an immediate danger to the public health or safety, because of an unsafe condition or improper maintenance, the City shall take such action as may be necessary to protect the public and make the facility safe. Any cost incurred by the City, as a result of the City Engineer's actions, shall be assessed against the owner(s) of the system.

a. No modifications shall be made to any privately owned stormwater system and/or detention facility, without a permit or other approval from the City.

8. Native Vegetation/Natural Basins. Should the owner(s) of a privately owned stormwater system and/or detention facility want to alter original construction to convert the system to provide increased water quality benefits and have a more natural appearance, such alternatives must be submitted by permit process to the City Engineer or his/her designee for review of detention facility functionality and approval.

a. Conversion examples include, but are not limited to, native grasses, wildflowers, removal of concrete swales, or alteration of outfall structures.

b. If approved, the owner(s) shall prepare and submit a maintenance schedule for the conversion. Modifications will be subject to inspection during conversion and continue after acceptance.

c. If approved, converted areas shall be excluded from mowing requirements as stated in Section 220.100, Weeds, but an alternative mowing/maintenance schedule shall be submitted and followed.

(1) Annual mowing will be required in efforts to prevent the vegetation from becoming excessive and basins from getting overgrown. All conversion-permitted basins shall be mowed by November 1 of each year. Failure to meet this requirement will result in enforcement in accordance with Section 220.100.

d. Maintenance of such systems will continue to be the responsibility of the property owner(s) as stated in Subsection (E)(2) through (7).

e. Under no circumstances does the altercation from a detention facility to a native vegetation area waive the requirements for detention.

9. Upon acceptance of public detention facilities by the City Council, the stormwater detention facility may be dedicated to the City for perpetual maintenance. Any such system shall include adequate perpetual access and sufficient area for maintenance by the City personnel and vehicles.

Section 405.245 Erosion And Sediment Control Requirements. [1]

[Ord. No. 7138, 9-26-2024]

A. Purpose And Intent. This Section specifies or authorizes performance and design standards for a Stormwater Pollution Prevention Plan (SWPPP) to reduce the amount of sediment and other pollutants in stormwater discharges associated with the land disturbance activities as required by these regulations, in addition to outlining the process by which any violations will be addressed. The applicant's engineer shall select and design erosion and sediment controls and stormwater best management practices adequate to meet those requirements, subject to review and approval by the City as hereinafter provided. Because violations of proper erosion and sediment control and stormwater best management practices pose risks to adjacent properties, affected bodies of water, other natural resources, etc., it is the intent of the City of O'Fallon to enact these policies and procedures which work to protect and promote the public health, safety and general welfare, through proper erosion and sediment control during construction activities.

B. Performance Standards. Designs for a SWPPP, including erosion and sediment controls and stormwater best management practices, shall meet the following performance standards:

1. Compliance with the Missouri Clean Water Law (Chapter 644, RSMo., as amended), the Federal Water Control Act (Public Law 95-500, 92d Congress, as amended), and Missouri and Federal regulations pursuant thereto.

2. Compliance with all standards imposed by Missouri Department of Natural Resources Missouri State Operating Permit MO-R100A; provided, however, if the land disturbance area is within a valuable water resource area as determined by the Missouri Department of Natural Resources, the SWPPP shall comply with all standards imposed by a Missouri State Operating Permit MO-R109 issued in compliance with the Missouri Clean Water Law (Chapter 644, RSMo., as amended), the Federal Water Control Act (Public Law 95-500, 92d Congress, as amended), and Missouri and Federal regulations pursuant thereto.

3. Compliance with the following additional standards stated herein:

a. All erosion and sediment control measures shall be fully installed and implemented prior to any work necessitating major land disturbance so as to prevent the flow or runoff of mud, silt, dirt, debris and other materials onto streets, sidewalks and other public rights-of-way. Additionally, positive steps shall be exercised to prevent mud, silt, dirt, debris and other materials from damaging adjacent property and silting up all storm drainage systems whether on- or off-site.

b. No land disturbance activity shall result in the impounding of surface water on property other than the permittee's unless the permittee obtains easements or licenses for that purpose.

c. Runoff into receiving streams from any area undergoing land disturbance activities that is greater than three (3) acres shall not exceed the two (2) year twenty-four (24) hour peak runoff rate for that area in its pre-developed state.

d. Temporary discharges into receiving streams from any area undergoing land disturbance activities shall not result in the accelerated erosion of those streams' channels at the point of discharge.

e. If temporary facilities and erosion and sediment controls installed pursuant to approved plans fail to meet the performance standards set out herein, the Director of Engineering or their designee may require the permittee to submit modified plans which meet the required standards.

f. For storms exceeding the design storm (fifteen-year, twenty-minutes), any silt or debris leaving the site and affecting public rights-of-way or stormwater drainage facilities shall be cleaned up within twenty-four (24) hours after the end of the storm.

C. Design Criteria.

1. SWPPPs for a development site shall be designed in accordance with the Protecting Water Quality Field Guide (latest edition as prepared by the Missouri Department of Natural Resources).

2. The erosion and sediment controls and temporary facilities shall be designed to accommodate, at a minimum, the runoff for the design storm specified herein, using the runoff coefficients specified in Table 1 and calculated according to the methods defined in this Section.

a. Design Storm. Designs for erosion and sediment controls and temporary facilities constructed during land disturbance activities shall be sufficient at a minimum to accommodate stormwater flows from a fifteen-year, twenty-minute storm.

b. Runoff Coefficient. The runoff coefficient (C) corresponds to the effective runoff based on ground cover, ground slope and that portion of rainfall that is lost to surface runoff by processes such as depression storage, infiltration, interception and evaporation. The runoff coefficients in Table 1 shall be used in calculating peak runoff rates and stormwater volumes.

Table 1 — Runoff Coefficient Table (C)
Ground Cover	Runoff Coefficient (C)
Pasture and unimproved areas	15%
Woods	10%
Lawns < 6% slope	15%
Lawns > 6% slope	30%
Graded/no vegetation < 6% slope	50%
Graded/no vegetation > 6% slope	60%
Gravel parking lot	75%
Gravel road	80%
Pavement, walks, buildings	95%

The runoff coefficients shall be determined for each drainage area to proposed erosion and sediment control and temporary facilities based on the following criteria:

(1) Land disturbance areas shall be considered stripped of all vegetation in determining runoff for erosion and sediment controls placed prior to land disturbance activities.

(2) After cut and fill operations are completed, land disturbance areas shall be considered stripped of all vegetation in determining sediment controls, runoff conveyance systems and erosion prevention devices.

c. Stormwater Runoff Calculation Method. The Rational Method, as developed by Mulvaney in 1851, shall be used to determine the peak (maximum) runoff rate. The Rational Method (also known as the Rational Formula) is:

Q_WET = C * i * A

Where:
QWET	=	total stormwater runoff in cubic feet per second (cfs)
C	=	runoff coefficient (dimensionless)
i	=	4.55 (rainfall intensity rate, inches per hour)
A	=	drainage area in acres (ac)

(1) The drainage area for erosion and sediment control facilities is limited to the following:

Sediment Trap: Less than five (5) acres. Limited to eighteen (18) months of structural life.

Sediment Basin: Twenty (20) acres or less. Limited to ten (10) years of structural life.

Silt Fence: Maximum length is six hundred (600) feet. Ends should be flared uphill. Location shall be in accordance with DNR recommendations specified in Field Guide. Must be checked after each rain event and repaired within forty-eight (48) hours. Limited to three (3) months of structural life.

(a) Two percent (2%) slope or less — one-fourth (1/4) acre per one hundred (100) feet.

(b) Two percent (2%) to five percent (5%) slope — one-fourth (1/4) acre per seventy-five (75) feet.

(c) Five percent (5%) to ten percent (10%) slope — one-fourth (1/4) acre per fifty (50) feet.

(d) Ten percent (10%) slope or greater — one-fourth (1/4) acre per fifteen (15) feet.

(2) The runoff coefficients (C) to be used are set out in tabular form in Table 1, above.

(3) The rainfall intensity rates: (i) were derived using Figure 4-1 from the Metropolitan St. Louis Sewer District Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and Stormwater Drainage Facilities, 2018 Edition.

(4) In addition to the stormwater storage that occurs during a rain event (Q_WET), the equivalent amount of dry storage (Q_DRY) is further required in the event that a second storm occurs before the storage facility has had a chance to drain the existing stormwater.

d. Sediment Storage Volume Calculation. The total volume of sediment storage within a storage facility shall be based on the drainage area, in acres, which is:

V = A * 1,800 (for Sediment Storage within a Trap)
V = A * 3,600 (for Sediment Storage within a Basin)
Where:
V	=	total sediment storage volume in cubic feet (cf)
A	=	drainage area in acres (ac)

(1) The runoff coefficients (C) to be used are set out in tabular form in Table 1, above.

e. Total Storage Volume Calculation. The total storage volume for determining sizing of storage structure is the combined volumes of stormwater (wet and dry) and sediment storage with an additional one (1) foot of freeboard to the spillway elevation or top of berm.

SV_T = Q_WET + Q_DRY + V + 1 ft (Freeboard)

D. Surface Stabilization Requirements.

1. Surface Stabilization Techniques. Bare ground must be stabilized by vegetation, rock surfacing, erosion control blankets and netting, soil binders, structural topping, like concreting or other techniques authorized by the Protecting Water Quality Field Guide (latest version as prepared by the Department of Natural Resources). With respect to vegetation, the following provisions shall also apply:

a. Temporary seeding shall be used if the area will be disturbed later in the development. The area must be vegetated by permanent seeding or sodding, when no further land disturbance will occur.

b. Seeding, fertilizing and mulching shall be applied at the rates and times specified in the Protecting Water Quality Field Guide (latest edition as prepared by the Department of Natural Resources).

c. Mulch can be used as temporary cover in unseeded areas to protect against erosion over the winter or until final grading and shaping can be accomplished. Application rates are shown in the Stormwater Management Policy.

d. Temporary seeding and mulching shall be placed on at least seventy percent (70%) of the total disturbed site area according to the stabilization schedule.

e. Temporary seeding may be suspended in portions of the project area which have an active building permit. Upon completion of the building activity, the site must be permanently stabilized.

f. Seeded areas shall be refertilized four (4) weeks after initial seeding. The seeded area shall be inspected at that time for uniform cover and adequate density. All areas which are bare or sparse [less than thirty percent (30%) ground cover] shall be reseeded and mulched.

g. Non-degradable mats shall be used only as a permanent installation and in areas that will not be mowed.

2. Surface Stabilization Schedule. Land disturbance activities shall be scheduled as provide in the table below:

Table 2 — Soil Stabilization Schedule
Soil Disturbance Activity or Condition	Required Stabilization Time
Soil disturbance has ceased in areas greater than 2,000 square feet.	14 days
After construction of dikes, swales, diversions and other concentrated flow areas.	5 days
When slopes are steeper than 3 horizontal to 1 vertical.	7 days
When slopes are greater than 3% and longer than 150 feet.	14 days
Perimeter controls around soil stockpiles.	End of workday
Stabilization or covering of inactive stockpiles.	30 days
When land disturbance is completed, permanent soil stabilization must be installed.	30 days

3. Land Disturbance Phasing. Land disturbance activities shall be scheduled in stages of development, so that only the areas that are actively being developed are exposed. Land disturbance areas exceeding ten (10) acres in total shall require phasing. A phasing plan, including the size and schedule of activities for each phase, is to be submitted to the Director of Engineering for review and approval, together with documentation concerning the need to disturb more than ten (10) acres at a time and the additional measures to be taken to ensure site stability.

When evaluating the proposed phases of development, the Director of Engineering shall consider the following factors and such additional factors as the Director deems relevant based on the circumstances of the project under consideration:

a. Overall size of the development.

b. Proposed contours/existing graded conditions.

c. Soil composition on the site.

d. Size of watershed affected by the development.

e. Presence of streams, creeks or other natural water courses on the site.

f. Interim/transitional SWPPP plans.

g. Additional/alternative erosion control measures.

h. Construction timing and ability to grow ground cover.

4. Surface water shall be diverted from the face of all cut and fill slopes exceeding eight (8) feet in vertical elevation.

5. Slope breaks shall be provided whenever the vertical elevation of any slope exceeds twenty (20) feet.

6. Diversion berms shall not exceed eight hundred (800) feet in length.

7. No excavation shall be made so close to the property line to endanger any adjoining public or private property without supporting and protecting such public or private property from settling, cracking or other damage.

8. No fill material shall be placed so as to cause or to allow the same to be deposited upon or to flow onto another property without written consent of the owner.

9. No fill material shall be placed so as to cause or to allow the same to be deposited upon or to flow onto any public street, walk, place or way, nor so close to the top of a bank of a channel as to create the possibility of bank failure.

10. Materials for fills shall consist of material obtained from excavation of banks, borrow pits or other approved source. Material shall be free of vegetative matter and deleterious material and shall not contain large rocks or lumps except as certified by a geotechnical engineer to be acceptable fill material.

11. No cut or fill slope shall be made steeper in slope than three (3) horizontal to one (1) vertical without being certified by a geotechnical engineer as to its stability and approval by the Director of Engineering.

12. Individual and isolated slopes, rock dikes, undisturbed natural slopes and slopes blending with the natural terrain may be steeper than the requirements as approved by the Director of Engineering.

13. All fills and trench backfills shall be compacted to the minimums as defined in the Stormwater Management Policy. Compaction of fills and backfills must be certified by a geotechnical engineer.

14. Solid rock, shale, tree stumps, masonry and other obstructions shall be removed to a depth of two (2) feet below finished grade or pavement subgrade.

15. Tree Preservation. If any trees are to be preserved on site per the approved plans, protection for the trees (in the form of construction fencing, snow fencing, or other high visibility barrier) shall be constructed and placed at the drip line of the tree canopy. No land disturbance activities shall take place within the barrier.

E. Stormwater Conveyance Requirements.

1. Temporary conveyance of stormwater during land disturbance activities depends upon the peak runoff for the design storm and a suitable method to prevent erosion after construction. The requirements listed below shall be used for temporary conveyance of stormwater:

a. All drainage shall be designed to transport surface waters to the nearest practical storm drain, natural watercourse or street as approved by Engineering Review.

b. Diversion channels and ditches are to be designed to a non-erosive velocity as defined in the geotechnical report required for the site. Diversion ditch length shall not exceed eight hundred (800) lineal feet.

c. A rock outlet is required at all pipe and improved channel discharges to open watercourses. The maximum design velocity shall be seven (7) feet per second (fps). If the discharge velocity exceeds seven (7) fps, an engineered energy dissipater shall be required.

F. Sediment Control Requirements.

1. A temporary construction vehicle wash-off pad is required to avoid tracking mud onto public roads and must be located where construction traffic leaves the site. The permittee shall remove any mud, sediment or debris tracked onto public roads by sweeping or other mechanical means on a daily basis (sweeping to be performed at the end of the day, unless existing conditions are such that require additional sweeping to be performed), or as requested by the Director of Engineering or their designee. A water truck may be required to facilitate vehicle cleaning or roadway cleaning, if needed.

2. Sediment basins shall be used to meet water quality discharge requirements and predeveloped runoff rates during land disturbance activities. Sediment basins shall be designed for the following criteria:

a. Sediment volume shall be determined in accordance with Subsection (C)(2)(d).

b. Dewatering time shall be twenty-four (24) hours for the total volume of wet storage of the basin.

c. The outlet must be designed to convey the required runoff with a minimum one (1) foot freeboard between the water surface of the outlet and the top of the basin embankment.

G. Inspection Requirements.

1. The property owner, developer, his/her agent or applicant shall inspect all erosion control on a weekly basis. An inspection report summarizing the inspection and any noted deficiencies shall be submitted weekly to the O'Fallon Stormwater Management Coordinator.

2. The property owner, developer, his/her agent or applicant shall inspect all erosion control and correct any deficiencies within forty-eight (48) hours of the end of any storm producing more than one-quarter (1/4) inch of rain at the project site.

3. The Director of Engineering, the Stormwater Management Coordinator, Construction Inspector or other designee may inspect all erosion control at any time as required.

H. Erosion And Sediment Control Violations.

1. If a violation concerning erosion or sediment control (examples, include, but are not limited to, non-compliant/incorrect installation of items noted on a SWPPP, failure to comply with a SWPPP (City-approved stormwater pollution prevention plan) for a site that results in sediment leaving the property, entering streets or the stormwater system, erosion occurring on site, failure to correct noted deficiencies, etc.) occurs or if the erosion and sediment control fails to meet the required performance standards within or on a site currently under development within the City of O'Fallon, as determined by the Director of Engineering or their designee, the procedure outlined in the Subsection (H)(2), below shall commence immediately.

2. Erosion And Sediment Control Violation Procedure.

a. Any conditions found by the Director of Engineering or their designee to be violations or items not in conformance with the SWPPP shall be reported to the site supervisor or appropriate personnel with oversight of SWPPP compliance.

b. The permittee shall have seven (7) calendar days after notification of a violation, commencing the working day following the day on which the violation notice was provided, to complete remediation or corrections. The Director of Engineering or their designee, may grant an extension, if the permittee reasonably demonstrates that the repairs cannot be made within the specified timeframe.

c. A subsequent reinspection of the site shall be conducted by the appropriate City personnel. If any items have not been remedied to conform with the approved SWPPP, the City Administrator can issue a Stop Work Order for the site, per Section 405.500. Any and all activities related to construction with the exception of work related to remediating SWPPP items, shall cease until such remedies have been made.

d. It is an ordinance violation, punishable as provided in Section 100.010, for any permittee, developer, construction company or other party to proceed with work not related to the SWPPP or in any way violate the Stop Work Order. In addition, such a violation may result in the suspension or revocation of all approval or permit(s) to conduct work on the site.

[1] Editor's Note: Former Section 405.245, Stormwater Quality Management And Illicit Discharge Control, was repealed 7-27-2023 by Ord. No. 7034. See now Section 407.040. Prior history includes R.O. 2008 and Ord. No. 6496.

Section 405.247 Stormwater Quality — Best Management Practices.

[R.O. 2008 § 405.247; Ord. No. 6496, 9-13-2018]

A. Purpose And Intent. Two (2) consequences of construction and development are increased runoff created by the changed properties of ground surface and the rate of discharge of this increased runoff. These are both of great relevance to stormwater. The natural condition of the land before development is in relative balance with the natural capacity of the receiving creeks. Normally, the undeveloped conditions provide greater permeability and longer times of concentration. By modification of the ground surface from the irregular, pervious and vegetation-covered, the areas are changed to more impervious, more quickly drained and, in some cases, denuded of vegetation. It is the policy of the City to protect and promote the public health, safety and general welfare. The management of stormwater will reduce the erosion on land and creek channels, will reduce the possibility of damage to public and private property, and will assist in the attainment and maintenance of water quality standards, and will preserve the environmental quality of the watercourses in the City.

B. Requirements — Creek Bank Setback.

1. Development along natural watercourses shall have residential lot lines, commercial or industrial improvements, parking areas and driveways set back a minimum of twenty-five (25) feet from the top of the existing stream bank. This is not meant to prevent access across creeks. Except as otherwise provided herein or as allowed by the City, the section of land between a natural watercourse and lot lines shall be designated as common ground and drainage easement to be maintained by the trustees or owners' association of the subdivision within all types of developments. Only for non-residential subdivisions in lieu of the common ground requirement, the section of land between the natural watercourse and twenty-five (25) feet from the top of bank can be:

a. Private property with an easement dedicated to the trustees or owners' association requiring maintenance of the areas as the responsibility of the trustees or owners' association;

b. Private property subject to a conservation easement in favor of an organization or land trust dedicated to environmental protection or land preservation such as Trailnet, Inc., the Open Space Council for the St. Louis Region or similar organization;

c. Set aside in a stream bank mitigation program approved by the United States Army Corps of Engineers under the provisions of the Clean Water Act.

2. All developments shall maintain a setback minimum of fifty (50) feet from the top of the existing bank to any building structure requiring a construction permit that necessitates excavation or also requires a foundation. Commercial and industrial areas shall have creek areas dedicated as drainage easements. Notwithstanding the foregoing setback requirements, an applicant may obtain a variance to develop within the stream buffer area from the City, provided the applicant is able to demonstrate that the water quality and stream morphology will not be adversely affected or adequate mitigation is provided to offset such adverse effects. Mitigation may include, but not be limited to, the following:

a. Installing additional erosion and sediment control;

b. If the stream has the potential for lateral movement, installing stream stabilization practices within the stream;

c. For those sites where vegetation does not exist, establishing vegetation; and/or

d. Additional tree planting.

C. Post-Construction — Water Quality. In order to preserve the quality of water in natural streams, it is important to provide a mechanism to remove contaminants on the site prior to water entering the natural watercourse. Typically called post-construction BMPs (best management practices), these methods identify a critical water quality volume that will need to receive a treatment to remove certain contaminants. These improvements, whether structural or non-structural, will remain in place after the construction is completed. The concepts introduced in the following Subsections are taken from the Georgia Stormwater Management Manual, Volume 2, August 2001. Nothing in the following Subsections shall change or replace any of the City's detention ordinances.

1. Water Quality Volume (WQv).

a. The water quality volume (denoted as the WQv) is the storage needed to capture and treat the runoff from ninety percent (90%) of the recorded daily rainfall events. In numerical terms, it is equivalent to one and fourteen hundredths (1.14) inches of rainfall multiplied by the volumetric runoff coefficient (Rv) and site area. The WQv is directly related to the amount of impervious cover created at a site. A minimum WQv of two-tenths (0.2) inches per acre shall be met at all sites.

b. Redevelopment projects can appeal to the Planning and Zoning Commission to reduce or eliminate WQv if it can be shown that there are stormwater enhancements being provided.

2. As a basis for determining water quality treatment volume, the following assumptions may be made:

a. The water quality volume WQv for off-site areas is not required. The following equations are used to determine the storage volume, WQv (in acre/feet of storage):

WQv	=	[(P)(Rv)(A)]/12
P	=	1.14 inches of rainfall

Where:
	WQv	=	Water quality volume (in acre-feet)
	Rv	=	0.05 + 0.009 (I) where I is percent impervious cover
	A	=	Area in acres

b. Measuring Impervious Cover. The measured area of a site plan that does not have vegetative or permeable cover shall be considered total impervious cover.

c. Multiple Drainage Areas. When a project contains or is divided by multiple drainage areas, the WQv volume shall be addressed for each drainage area.

d. Off-Site Drainage Areas. The WQv shall be based on the impervious cover of the proposed site. Off-site existing impervious areas may be excluded from the calculation of the water quality volume requirements.

e. BMP Treatment. The final WQv shall be treated by an acceptable BMP(s) from the list presented in this Chapter.

f. Extended Detention For Water Quality Volume. The water quality requirements can be met by providing a twenty-four-hour draw down of a portion of the water quality volume (WQv) in conjunction with a stormwater pond or wetland system.

D. Acceptable Urban BMP Options.

1. This Subsection sets forth five (5) acceptable groups of BMPs that can be used to meet the water quality volume criteria (WQv). The design and selection of these BMPs should comply with the Georgia Stormwater Management Manual as prepared by the State of Georgia.

2. Where the City's criteria or requirements are more stringent, then they shall govern. Adapting to local Missouri environment and natural conditions should be expected but shall be as approved by the City or a higher authority.

The acceptable BMP designs are assigned into five (5) general categories for stormwater quality control (WQv):

a. BMP Group 1 stormwater ponds.

b. BMP Group 2 stormwater wetlands.

c. BMP Group 3 infiltration practices.

d. BMP Group 4 filtering practices.

e. BMP Group 5 open channel practices.

3. See Section 1.3 of the Georgia Stormwater Management Manual for additional BMP options. Section 3 of the Georgia manual has detailed descriptions of each control.

4. To be considered an effective BMP for stand-alone treatment of WQv, a design shall be capable of:

a. Capturing and treating the required water quality volume (WQv).

b. Removing eighty percent (80%) of the TSS.

5. A combination of BMPs and/or credits is normally required at most development sites to meet all three (3) stormwater sizing criteria.

a. BMP Group 1. Stormwater Ponds. Practices that have a combination of permanent pool, extended detention or shallow wetland equivalent to the entire WQvs include:

(1) P-1 micropool extended detention pond.

(2) P-2 wet pond.

(3) P-3 wet extended detention pond.

(4) P-4 multiple pond system.

(5) P-5 pocket pond.

b. BMP Group 2. Stormwater Wetlands.

(1) Practices that include significant shallow wetland areas to treat urban stormwater but often may also incorporate small permanent pools and/or extended detention storage to achieve the full WQv include (Modification of existing wetland areas will require a Corps 404 permit.):

(a) W-1 shallow wetland.

(b) W-2 ED shallow wetland.

(c) W-3 pond/wetland system.

(d) W-4 pocket wetland.

(2) Wetlands shall not be used for control of water quantity (i.e., the flood protection volume).

c. BMP Group 3. Infiltration Practices.

(1) Practices that capture and temporarily store the WQv before allowing it to infiltrate into the soil over a two-day period include:

(a) I-1 infiltration trench.

(b) I-2 infiltration basin.

(2) Infiltration practices will be allowed on sites where it is proven that infiltration will work. Percolation rates shall be determined for proper use.

d. BMP Group 4. Filtering Practices.

(1) Practices that capture and temporarily store the WQv and pass it through a filter bed of sand, organic matter, soil or other media are considered to be filtering practices. Filtered runoff may be collected and returned to the conveyance system. Design variants include:

(a) F-1 surface sand filter.

(b) F-2 underground sand filter.

(c) F-3 perimeter sand filter.

(d) F-4 organic filter.

(e) F-5 pocket sand filter.

(f) F-6 bioretention.*

(g) F-7 proprietary filtering system.

*May also be used for infiltration.

(2) A maintenance agreement and maintenance schedule shall be required.

e. BMP Group 5. Open Channel Practices.

(1) Vegetated open channels that are explicitly designed to capture and treat the full WQv within the dry or wet cells formed by check dams or other means include:

(a) Dry swale.

(b) Wet swale.

(c) Filter strips.

(2) Open channel practices shall be designed with the proper plantings. Wet swales shall be designed to drain out over time.

Section 405.250 Sanitary Sewers.

[R.O. 2008 § 405.250; Ord. No. 6496, 9-13-2018; Ord. No. 7015, 4-27-2023]

A. All buildings, structures and uses of land in the incorporated area of the City of O'Fallon shall hereafter be required with an adequate, safe and sanitary disposal system for all human disposal of sewage or other liquidated wastes and shall conform to the methods outlined herein:

1. Where a public sanitary sewer main is reasonably accessible, in the opinion of the City, the developer shall provide the subdivision with a complete sanitary sewer system connected with such sewer main, including a lateral connection for each lot. Such systems and connections shall comply with the regulations of the Missouri State Board of Health and Missouri Department of Natural Resources, City of O'Fallon and the Duckett Creek Sewer District (where applicable).

a. Sanitary sewer systems outside the City of O'Fallon service area shall be reviewed and approved by the appropriate sewer district servicing the area. Approval letters shall be forwarded to the City of O'Fallon Engineering Department for service areas within the municipal boundaries.

b. All sanitary sewer laterals shall be Schedule 40 PVC material. The wye shall be installed at the same standard as the main.

c. Developers of commercial or industrial lots shall complete and submit to the City a sewer pre-treatment survey form.

2. It shall be the responsibility of the developer/applicant to comply with all requirements of the City of O'Fallon per Chapter 700, and/or Metropolitan St. Louis Sewer District (MSD), latest revision.

3. Verification of the service shall be provided at the time of submission of the preliminary plat.

4. Where no sewers are accessible and no plans for a sewer system have been prepared and approved, or where the topography restricts the use of reasonable gravity sewer mains, the developer shall provide a written engineering alternatives report, signed/sealed by a Missouri professional engineer, evaluating all of the options to service sewer for the site. This report should evaluate both gravity and mechanical options, costs, and maintenance responsibilities of each option, and provide pros and cons on each. Staff will review options and make recommendations for this development, and ultimately agree to one (1) or more of the solutions.

5. Review By The City's Sewer Consultant. The City's sewer consultant may be engaged to review the engineering alternatives report. The sewer consultant's report regarding the analysis will be forwarded as part of the petitioner's application to the Planning and Zoning Commission.

6. Should a mechanical system be the approved alternative, the developer shall either install a sewage collection and disposal system in accordance with the requirements of Subsection (A)(2) above or individual disposal devices may be installed on each lot within the subdivision, provided that no individual disposal device should be permitted unless the lots to be served have sufficient area to allow adequate soil absorption for on-site sewage disposal. The Planning and Zoning Commission may modify lot area requirements in relation to soil conditions and other pertinent facts and findings in any particular subdivision. All such individual devices and systems shall be constructed and maintained in accordance with the regulations and requirements of the Missouri Department of Natural Resources.

a. If a pump station is being considered in the City's district, the developer shall use the City's standard design, where applicable. The City's sewer consultant may be engaged to review any technical design report or documents pertaining to any final mechanical system. Any alterations of the City's standard design shall be reviewed and approved by the City and/or the City's sewer consultant. Said consultant shall provide recommendations to the City for the final design to be built with the development.

b. Any plan for a mechanical system shall be presented to Planning and Zoning, with the development. A concept level study will be required at the area plan or preliminary plat stage.

c. Any mechanical system shall be built in accordance to the City's requirements in order to provide a reliable system to the public.

7. For lots with individual water systems and sanitary sewage disposal systems, the applicant shall adhere to St. Charles County requirements regarding the minimum lot size.

Section 405.260 Water Supply.

[R.O. 2008 § 405.260; Ord. No. 6496, 9-13-2018]

A. Where a public water supply main is reasonably accessible, in the opinion of the City, the subdivision shall be provided with a complete water distribution system adequate to serve the area being platted, including a connection for each lot and appropriately spaced fire hydrants whose locations shall be reviewed and approved by the appropriate fire protection district. The water system shall be designed and constructed per the American Water Works Association (AWWA) standards and guidelines and approved by the City of O'Fallon, per Chapter 700, Public Utilities.

1. Water systems outside the City of O'Fallon service area shall be reviewed and approved by the appropriate water district servicing the area. Approval letters shall be forwarded to the City of O'Fallon Engineering Department for service areas within the municipal boundaries.

2. Where proposed developments are adjacent to municipal boundaries in the City water district and where fire flow demands are deficient, or where the area is served with no looped system, the developer may be required to connect to the outside agency's water system.

a. If required, the proposed connection will be recommended to the City Council as part of the Planning and Zoning review and approval of the proposed development.

b. Any hydraulic analysis shall require the City's model to be updated. The City's water consultant shall be engaged to review any technical design report or documents pertaining to any final system layout and to update the model.

B. For lots with individual water systems and sanitary sewage disposal systems, the applicant shall adhere to St. Charles County requirements regarding the minimum lot size.

Section 405.270 Gas, Wire Or Cable Utilities.

[R.O. 2008 § 405.270; Ord. No. 6496, 9-13-2018]

A. All lines for gas, telephone, electrical, television and other services distributed by wire or cable shall be placed underground throughout a development. Overhead lines may be permitted by the Planning and Zoning Commission where it is determined that such lines will not impair the health, safety, general welfare, design, appearance and character of the subdivision and only where such overhead lines are brought to the perimeter of the subdivision. This Section shall not be construed to prohibit the construction of aboveground or surface equipment associated with an underground distribution system, such as (but not limited to) surface-mounted transformers, power terminal pedestals, meters and meter boxes, concealed wires, streetlights and streetlight poles.

B. Utility lines shall be installed prior to occupancy permits being issued on a particular phase. Utilities wishing to install utility lines after occupancy permits have been issued on a particular phase shall be required to obtain a permit from the City for their excavation.

C. The City strongly prefers simultaneous ditching whenever feasible.

Section 405.275 Terraced And Vertical Retaining Walls.

[R.O. 2008 § 405.275; Ord. No. 6496, 9-13-2018]

A. A permit is required for all retaining walls that are over forty-eight (48) inches tall in height, measured from the top of the base to the top of the wall or for walls that support a surcharge load or that alter the channelized drainage of any lot or drainage area. For retaining walls requiring a permit, as-built plans are to be prepared by a certified licensed engineer when required by the Engineering Department.

B. Retaining walls shall not be placed any closer to another retaining wall as recommended by a geotechnical engineer or by a ratio of a minimum of two (2) feet horizontal for every one (1) foot of vertical height of wall.

C. Retaining walls in the front yard shall not exceed a height of four (4) feet and shall be set back a minimum of ten (10) feet from the front property line or outside the utility easement, whichever is greater. This requirement can be varied by the Planning and Zoning Commission or the Board of Adjustment.

D. Retaining walls in the side or rear yard shall not be built within two (2) feet from the property line. Retaining walls in side or rear yards over forty-eight (48) inches will not be allowed in public utility easements.

E. Retaining walls will not be allowed in public rights-of-way without written approval from the City Engineer and/or his/her designee.

F. A retaining wall may exceed four (4) feet in height if it has been designed and engineered by a licensed engineer; however, any wall shall not exceed six (6) feet in height without a fence or guard on top.

G. Any retaining wall more than thirty (30) inches tall which supports a walking surface that is within two (2) feet of the wall will require a guard on the retaining wall. The guard shall be constructed per the current edition of the International Building Code (IBC) or the International Residential Code (IRC), whichever is applicable.

H. Any resident who constructs a retaining wall within a public utility easement shall be financially responsible for the removal or reconstruction of the retaining wall, should the easement be needed, per Missouri law. Refer to the record plat of the subdivision for easement locations and sizes.

I. Any construction of a retaining wall requiring a permit shall include a drainage plan which provides for drainage around or away from the retaining wall and to be contained on site or drains to a City-approved location. Stormwater will not be allowed to flow over the retaining wall.

J. Retaining walls that alter the channelized drainage of any lot or drainage area shall not be constructed without prior approval and permitting from the City of O'Fallon Engineering Department regardless of the height of the wall.

K. Any person who wishes to construct a retaining wall that requires engineering shall submit signed and sealed engineering plans and calculations for the retaining wall and a site plan showing the location of the retaining wall to the City of O'Fallon Building and Code Enforcement Division for review. Upon approval, a building permit will be issued.

L. For additional requirements, see Chapter 500, Building Regulations.

Section 405.280 through Section 405.290. (Reserved)

Section 405.300 Large Lot (R1-A Single-Family Suburban Residential District) Residential Subdivisions.

[R.O. 2008 § 405.300; Ord. No. 6496, 9-13-2018]

A. The following is a list of exemptions in this Chapter for subdivisions zoned R1-A; all other requirements of this Chapter must be met:

1. Culs-de-sac and dead-end streets of reasonable length [normally not over eight hundred (800) feet] may be approved where necessitated by topography or where, in the opinion of the Planning and Zoning Commission, they are appropriate for the type of development contemplated.

a. Curb and gutter are not required; flat-bottom open drainage ditches, approved by the City Engineer and/or his/her designee, shall be provided in lieu of curb and gutter.

b. Sidewalks are not required except in situations where deemed appropriate by the Planning and Zoning Commission and/or the City Council in order to provide direct access for pedestrians to recreational areas, common ground, schools, churches, shopping areas, pedestrianways and multipurpose trails linking adjoining streets and neighborhoods.

c. Streetlights shall be required at all entrances and intersections and shall be provided at a maximum five-hundred-foot separation.

d. With the approval of the City Engineer and/or his/her designee, the maximum grade of a minor residential street can be increased to fifteen percent (15%) for short stretches of pavement. A short stretch of pavement is defined as being less than one hundred fifty (150) lineal feet not counting the curve and separated by approximately three hundred (300) lineal feet of grades at ten percent (10%) or less.

e. With adequate parking on driveways, pavement width can be reduced to twenty-foot width with three-foot rock shoulders on each side. No on-street parking would be allowed in this design. Adequate parking is defined as four (4) for more parking spaces on each driveway not counting the garage.

B. If residents of a large lot subdivision desire to install any of the above improvements, such installation shall be solely at the expense of property owners of said subdivision. The City of O'Fallon has no responsibility or obligation to provide such improvement or to share in such provision. The developer of a large lot subdivision shall include language to this effect in recorded restrictions as a condition of record plat approval.

Section 405.310 (Reserved)

Section 405.320 Streetlights.

[R.O. 2008 § 405.320; Ord. No. 6496, 9-13-2018; Ord. No. 7015, 4-27-2023]

A. Streetlights shall be provided in all subdivisions, except as stated under large lot residential subdivisions, Section 405.300. All streetlights shall have underground wiring and meet minimum specifications of the electric utility company serving the area of the proposed subdivision. Streetlights shall be placed at all intersections and in all culs-de-sac. A maximum of three hundred (300) feet separation shall be required, or in special cases a longer separation may be approved by the City Engineer and/or his/her designee. Streetlights shall be installed and functional prior to occupancy of structures within the subdivision.

B. New Public Streetlight Installations.

1. Within the City limits, there are multiple electric providers. The intent is still to have consistent streetlighting City-wide even though requirements may differ slightly.

a. In Ameren Missouri's territory, streetlights shall be installed by the developer in a manner that meets the specifications and rates for "Service Classification No. 6 (M) Street and Outdoor Area Lighting — Customer Owned" for unmetered service, seventy-one (71) watt minimum (LED-Light Emitting Diode) — standard at the energy and maintenance rate (if applicable, otherwise energy only). The City Engineer shall prepare more specific details for this specification. After inspection and acceptance by the City, the lighting facilities will be maintained and operated by the City. With the developer incurring the full cost of the light installations and connections, streetlight billing in new subdivisions shall be turned over to the City for payment once lights are turned on. Connection fees will be paid to the City by the developer with the City being responsible for payment of the connection fee to the utility company when the lights are ready to be turned on. The City will provide written direction to the electric company to add new lights to the City's bill. During the period when an escrow for streetlighting is in place, escrowed funds may be used for any maintenance expenses incurred or to be incurred by the City. The standard post top luminaries for the City shall be either the Early American style or the Colonial style.

b. In Cuivre River Electric Cooperative's territory, streetlights must be similar in style and installation to the lights noted in Subsection (B)(3) and installed according to Cuivre River Electric Cooperative's requirements. Until a rate is established, for a City-owned post-top light, the installation will be a company-owned light. When a new rate is established for City-owned streetlights similar to Ameren UE's customer-owned rate, streetlight installations shall be made in a manner that closely follows Subsection (B)(3).

2. All proposed streetlights shall have bulbs that are light-emitting diode (LED) technology, assuming the electric district has the current technology available. Any existing bulb shall be replaced with an LED counterpart when the existing bulb is no longer functional.

3. All specifications and requirements for the installations of streetlights shall adhere to the City of O'Fallon Specifications for the Installation of Streetlights Policy, latest edition. This manual is available on the City of O'Fallon Engineering website or can be available by contacting the Engineering Department.

4. After inspection and acceptance by the City, the lighting facilities will be owned, maintained and operated by the City. With the developer incurring the full cost of the light installations and connections, streetlight billing in new subdivisions shall be turned over to the City for payment once lights are turned on. Connection fees will be paid to the City by the developer with the City being responsible for payment of the connection fee to the utility company when the lights are ready to be turned on. The City will provide written direction to the electric company to add new lights to the City's bill.

5. For any cellular or telecommunications devices that are to be placed on a streetlight, the owner of the cellular or telecommunications devices shall assume all electric costs for the light. If the City is already paying for the electric costs, then that electricity fee will remain with the City until all cellular or telecommunication devices are installed and ready to be turned on.

a. Said streetlight shall remain operational per the City requirements. Continuous and proper function of the streetlight will be required as a condition of approval for shared use on the pole. Failure to meet this requirement could result in the required removal of the equipment.

b. Planning and Zoning Commission approval may be required prior to construction. The applicant shall contact the Director of Planning and Development for the process.

c. A separate permit through the City will be required for plan approval and prior to construction. An agreement may also be required as part of the terms and conditions of connecting to the pole.

C. New Private Streetlight Installations. (Streetlights not owned by the City and typically where a homeowners' association or private land owner is the customer.)

1. As an alternative to public-provided streetlights, the subdivision may opt to have private streetlights (non-City owned/maintained) installed. Should this option be utilized, the private streetlighting plan must be approved by the Planning and Zoning Commission with the development.

2. Lighting on private streets and other areas will not be paid for by the City.

3. The City Attorney and Department of Engineering must approve the language in the covenants and restrictions that provides for the perpetual payment of streetlighting expenses by the homeowners' association, in a manner that ensures the lights will always be privately owned, and not revert to City-owned lights in the future.

4. The specifications for the private lights as provided for in this Subsection shall be equal to or better than the City lighting standards, including the LED requirement, with the exception of the disconnect as required by the utility company. All proposed streetlights shall have bulbs that are light-emitting diode (LED) technology, assuming the electric district has the current technology available. Any existing bulb shall be replaced with an LED counterpart when the existing bulb is no longer functional.

D. This Section pertains to lights on City streets only which are designed to be dedicated to the City for public use. Lighting on private streets and other areas will not be paid for by the City and, therefore, this Section is not applicable to those installations.

Section 405.330 through Section 405.360. (Reserved)

Section 405.370 General Street Design Standards.

[R.O. 2008 § 405.370; Ord. No. 6496, 9-13-2018]

A. The design of streets shall be designed in accordance with the latest edition of the Saint Louis County Transportation Design Criteria for the Preparation of Improvement Plans and the Manual of Uniform Traffic Control Devices (MUTCD) except as modified by the City of O'Fallon. Designs shall also incorporate the Traffic Management Policy as adopted by the City of O'Fallon. All streets shall be constructed to St. Louis County Highway Standards except as modified by the City of O'Fallon.

B. Minimum design requirements shall be as detailed in the table below.

[Ord. No. 6855, 12-16-2021]

	Standard Detail Number	ROW Width	Pavement Width	Lane Width	Number of Drive Lanes	Utility Easement	Design Speed
Arterial	C203.64	84	63	12	5	10	40
Collector (urban)	C203.71	60	39	12	3	10	35
Collector (residential)	C203.84	60	38	n/a	2	10	25
Minor residential/ Local Access	C203.82	50	26	n/a	2	10	25*

NOTES:
*	Can be varied with City Engineer's approval. Minimum posted speed shall be twenty-five (25) miles per hour.
	These requirements may be varied by other City ordinances.
	Narrower pavement widths can be approved following Subsection (C) of this Section.
	Parkway options can be provided with the City Engineer's approval.

C. The above standards are to be considered minimum standards. Variations in the above standards can be made if supported by the Director of Planning and City Engineer and further approved by the Planning and Zoning Commission. Changes must provide for the health, safety and welfare of the community.

1. Reduced pavement widths shall be considered along with a package of enhanced landscaping, enhanced pedestrian facilities and other community improvements. A traffic study that includes a parking analysis will be required for projects requesting reduced pavement widths. The City's Planning Department will maintain a list of cross sections along with the circumstances that make the reduced width cross section suitable for the situation.

D. Center medians can be utilized where left-turn lanes are not required.

Section 405.380 (Reserved)

Section 405.390 Required Subdivision Design And Improvement Standards — Street Standards.

[R.O. 2008 § 405.390; Ord. No. 6496, 9-13-2018]

A. General Standards.

1. Street design shall attempt to preserve existing topography as nearly as possible. Streets shall intersect, as nearly as possible, at right angles. Street jogs with center-line offsets of less than one hundred twenty-five (125) feet are prohibited.

2. Streets will not be approved which are subject to flooding or frequent inundation.

3. The system of streets designated for the subdivision, except in unusual cases, must connect with any streets already dedicated in adjacent subdivisions; and where no adjacent connections are platted, must in general be the reasonable projection of streets into adjacent tracts and must, except in unusual cases, continue to the boundaries of the tract subdivided, so that other subdivisions may connect therewith.

4. The City Engineer may require a street to be dedicated to public use in order to provide circulation.

5. Underdrains shall be required and installed per Exhibit A in Appendix D.[1]

[1] Editor's Note: Appendix D is included as an attachment to this Chapter.

B. The following standards shall apply to all streets:

	Maximum Grade (percent)	Minimum Grade (percent)	Radius of Curve (center)	Corner Radii
Arterial	5%	2%*	400	50
Collector	8%	2%*	350	50
Residential collector	10%**	2%*	200	37
Minor residential	10%	2%*	150*	37
Cul-de-sac	10%	2%*	150*	37

NOTES:
*	Can be varied with City Engineer's approval
**	Some streets within large lot subdivisions may be higher per Section 405.300.
	These standards are minimum standards.

C. Cul-De-Sac And Stub Streets (Dead-End Streets To Be Extended In The Future).

1. In subdivisions with no through streets where the distance to the through street exceeds one thousand three hundred (1,300) feet, a fifty-five-foot pavement radius and a sixty-seven-foot right-of-way radius will be required on at least one (1) cul-de-sac in order to facilitate school bus circulation.

2. Cul-de-sac and dead-end streets of reasonable length may be approved where necessitated by topography or where, in the opinion of the Planning and Zoning Commission, they are appropriate for the type of development contemplated.

3. All culs-de-sac shall have a minimum right-of-way radius of fifty-four (54) feet and a pavement radius of forty-two (42) feet. It is advisable to contact the School District and Fire Department for the minimum radius of the culs-de-sac for a proposed development prior to submitting plans to the City.

4. Stub streets over two hundred fifty (250) feet in length shall have a minimum temporary turnaround pavement radius of forty (40) feet, covered by a temporary turnaround easement to remain until the road is extended and platted. In lieu of turnarounds, the Planning and Zoning Commission may approve a "T"- or "Y"- shaped paved space on streets which are less than two hundred fifty (250) feet in length and are planned to be extended in the future.

5. All stub streets must provide three (3) standard specification, "Manual on Uniform Traffic Control Devices," end of roadway markers mounted on two-pound "U" channel sign posts. Each marker shall consist of an eighteen-inch diamond reflectorized red panel. The bottom of each panel shall be mounted a minimum of four (4) feet above the elevation of the permanent surface and installed at the terminus of pavement.

D. Alleys. Alleys, when platted, shall be designated as private. The width, depth and type of pavement shall meet the intended use. The minimum pavement width shall be sixteen (16) feet. Reduced pavement widths can be considered with the same requirements as contained in Section 405.370 for roadways. At a minimum, the pavement shall be six (6) inches of Portland cement concrete. The minimum horizontal radius shall be forty (40) feet at the center line of the alley. The intersection of the alley pavement with the public pavement shall have a minimum thirty-seven-foot radius at the edge of the alley pavement. Alleys shall:

1. Be designated and signed for one-way traffic;

2. Have a minimum five-foot-wide easement strip placed adjacent to the right side of the alley easement designated for street maintenance and trash receptacle placement;

3. Be designated and signed to prohibit on-street parking; and

4. Be designated and signed as private streets in accordance with Section 400.264 of this Code.

E. Commercial/Industrial Streets. Commercial/industrial streets shall have the following design standards:

1. Commercial and industrial streets including culs-de-sac shall have a minimum right-of-way width of sixty (60) feet with thirty-nine (39) feet of pavement. The pavement in culs-de-sac shall be fifty-five (55) feet in radius with a right-of-way of sixty-seven-foot-wide radius.

2. Commercial and industrial arterial streets shall have a minimum right-of-way of eighty-four (84) feet.

3. Sidewalks are required on both sides of commercial streets. Industrial streets may have a sidewalk on one (1) side of the street if required by the Planning and Zoning Commission.

F. Sidewalks And Multipurpose Trails.

1. Sidewalks are required on both sides of all public and private streets except for:

a. Single-family residential subdivisions with an average lot size between one-half (1/2) acre and one (1) acre shall have sidewalks installed on one (1) side of the street.

b. Single-family residential subdivisions with a minimum lot size one (1) acre or larger shall not have sidewalks required.

c. Private alleys shall not have sidewalks required.

d. A sidewalk is not required on the side of the street where a multipurpose trail is required in lieu of a sidewalk.

e. Cul-de-sac streets shall have sidewalks installed on both sides of the street with the sidewalk terminating at the radius of the turnaround.

2. Sidewalks may be required by the Planning and Zoning Commission and/or the City Council on one (1) or both sides of the streets exempted above in order to provide direct access for pedestrians to recreational areas, common ground, schools, churches, shopping areas, pedestrianways and multipurpose trails linking adjoining streets and neighborhoods. The Planning and Zoning Commission and/or the City Council may limit the requirement of sidewalks to one (1) side of the street in commercial, office and high-tech developments that are deemed to likely experience lesser amounts of pedestrian traffic.

3. Sidewalk Construction Requirements.

a. Sidewalks shall have a minimum pavement width of six (6) feet for arterial and of five (5) feet for collector streets and four (4) feet for all other streets. Sidewalks constructed immediately behind the curb shall be a minimum of one (1) foot wider than said widths.

b. Sidewalks shall have a lateral slope of one and one half percent (1 1/2%) with a tolerance of plus or minus (one half percent) 1/2%.

c. Sidewalks shall be placed within the street right-of-way, one (1) foot away from the property line.

d. Sidewalks shall be constructed of a minimum of four (4) inches of Portland cement concrete on a compacted rock leveling course with an average thickness of two (2) inches, except in driveways where it shall be a minimum of six (6) inches of Portland cement concrete on a compacted rock base with a minimum thickness of four (4) inches.

e. For any sidewalks that are through a driveway apron, refer to Section 405.210 for further requirements.

f. Accessible curb ramps shall be installed at all street intersections according to Federal regulations. The width of the sidewalk shall extend through the curb ramp.

4. Multipurpose Trails. Multipurpose trails shall be required in lieu of sidewalks where deemed appropriate according to the bike and trail plans approved by the Planning and Zoning Commission and/or the City Council. Multipurpose trails shall have a minimum pavement width of ten (10) feet and shall be constructed of a minimum of three (3) inches of asphaltic concrete on a compacted rock base with a minimum thickness of four (4) inches. Concrete may be used in lieu of asphalt for construction of trails, and shall adhere to the design requirements of Subsection (F)(3) above. Multipurpose trails shall be placed within a minimum twelve-foot-wide trail easement. Accessible curb ramps shall be installed at all street intersections according to Federal regulations. In residential areas, wider-than-normal sidewalks or paths may be utilized as a developer- or builder-selected optional enhancement for the community, but these sidewalks or paths will not be considered multipurpose trails unless they are ten (10) feet wide. The width of the trail shall extend through the curb ramp.

5. Required fee in lieu of sidewalk or multipurpose trail installation. If it is determined by the City Engineer that it would be in the best interest of the City to postpone the installation of sidewalks and/or multipurpose trails, the adjacent property owner shall be required to make a cash contribution to the City (or other applicable government agency) in lieu of the sidewalk and/or multipurpose trail installation. Said fee shall be calculated as a fixed amount per lineal foot based on the estimated cost as of the date that escrows are established. Typically, this estimate shall be made by the owner's agent and submitted to the City for review and approval. At a time to be determined by the City, the City will be required to install sidewalks and/or multipurpose trails on this property. Once the sidewalk or multipurpose trail fee is paid for on a particular property, this lot shall no longer be required to provide a sidewalk or multipurpose trail. The fees collected herein shall be recorded as revenue in the City's Street and Road Improvement Fund.

G. One-Way Streets.

[Ord. No. 7056, 10-26-2023]

1. For residential streets containing driveways or mailboxes, the minimum pavement width shall be twenty (20) feet. Parking may be allowed on one (1) side of the street.

2. For residential streets that would strictly serve as a corridor, with no anticipated driveways or mailboxes, or a street that serves as an entrance to a subdivision with a median separating the lanes of traffic for a possible entrance monument/sign, the minimum pavement width shall be thirteen (13) feet, as long as the turn radius at intersections is sufficient to allow for adequate turning movement. No parking shall be allowed on these roadways.

3. The standard pavement typical section shall still be utilized regarding curbing, thickness, etc.

H. Private Streets.

[Ord. No. 7056, 10-26-2023]

1. Private streets shall only be considered for acceptance as a public street if the street(s) in question serves a public interest, as determined by the City Engineer.

2. Before the City will consider accepting the private street as a public street, a written and signed petition or petitions must be received from all of the trustees of the subdivision association controlling the right-of-way, or from all of the right-of-way owner(s) where there is no subdivision association.

3. Any right-of-way, easements and building setbacks shall be reviewed. Any required right-of-way or easements from the owners of the land shall be donated to the City, and all associated costs shall be borne by the applicant.

4. Private streets will only be accepted in their entirety. They shall never be accepted one-half (1/2) width or less than one (1) block at a time.

5. Streets shall have been constructed to meet the specifications of the current City Code in force at the time of application.

6. The applicant shall provide all information records about the street construction and maintenance.

7. The City Engineer or his/her designee shall inspect for deficiencies in the street(s). If the City Engineer determines that soil tests or pavement cores are necessary to accurately assess the condition of the pavement, the cost of this work, to be completed by a firm of the City's choosing, shall be borne by the property owner(s) applying for acceptance of the private street.

8. The City Engineer or his/her designee will inspect the existing private street and/or associated storm sewer systems, and will provide a recommendation to the City Council pertaining to the existing condition. Prior to the City's acceptance, current City standards for geometry, roadside safety and right-of-way width, along with identified preventative maintenance and needed repairs, must be completed. The property owners of the private street and private storm sewer system will be responsible for all work necessary to bring the facility into compliance with the City Engineer's inspection. If accepted, all necessary rights-of-way and easements will be dedicated to the City in accordance with current City standards. Any plans to repair or upgrade the private street and/or storm sewer systems must be submitted to the City Engineer for review, and any repair or upgrade work must be inspected and approved by the City Engineer following the same procedures as a new development.

9. In the event the residents cannot afford to make the improvements detailed in the City Engineer's inspection, the City Council may consider forming a Neighborhood Improvement District.

10. Except where private streets are accepted for public maintenance under the terms herein, no public funds will be expended for maintenance operations on private streets and/or private storm sewer systems, including, but not limited to, snow removal, pothole patching, resurfacing, storm sewer repairs or the like.

Section 405.400 through Section 405.490. (Reserved)