Ordinance No. 1178: DRAINAGE AND GRADING

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1 Ordinance No. 1178: DRAINAGE AND GRADING PURPOSE The regulation of drainage and grading in this subchapter is intended to accomplish the following benefits: (D) (E) Protect and enhance the quality of life and the general welfare of the village and its residents, and conserve and enhance the village s physical and aesthetic environment; Protect and maintain property values in a manner that ensures each property owner s enjoyment of his or her property; Provide for enhanced design of improvements to the natural environment of the village; Stabilize topsoil by preventing or minimizing soil erosion and sedimentation; and Assist in controlling stormwater run-off DEFINITIONS For the purposes of this subchapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning. When not inconsistent with the context, words used in the present tense include the future or past tense, and words in the singular include the plural. Words not defined in this section shall have their usual and customary meaning. DEPRESSIONAL STORAGE AREA. A low-lying area where stormwater collects; only regulated when the total storage volume of an individual depressional storage area exceeds five cubic feet. ILLINOIS URBAN MANUAL. The Illinois Urban Manual, 2013 edition, published by the Association of Illinois Soil and Water Conservation Districts. IMPERVIOUS SURFACE or IMPERVIOUS AREA. Any improvements on a lot that prohibit or substantially retard the drainage of stormwater directly into the soil below, as well as any hard-surfaced, compacted area that does not readily absorb or retain water, including but not limited to: buildings, driveways, sidewalks, patios, decks and similar structures; stone, brick, asphalt and concrete surfaces; graveled areas; swimming pools; and basketball or tennis courts or other hard play surfaces. LICENSED PROFESSIONAL ENGINEER. An engineer licensed in the State of Illinois, under the Professional Engineering Practice Act of 1989 (225 ILCS 325/1 et seq.). LOWEST FLOOR ELEVATION. The elevation of the lowest enclosed area of a building, such as a basement floor elevation. 1

2 MAINTENANCE ACTIVITIES. Ordinary repairs, in-kind replacement, or replacement with alternate materials, provided that the activity does not result in a change in: The area of land covered by an impervious surface; The size of a pipe; or The elevation of the ground surface. MAJOR PROJECT. A regulated activity that disturbs 400 square feet or more of the ground surface. MINOR PROJECT. A regulated activity that disturbs less than 400 square feet of the ground surface. NAVD88. The North American Vertical Datum of REGULATED ACTIVITY. Any activity described in Section REGULATED ACTIVITIES Permit required. No person, unless specifically exempted, shall commence any regulated activity without first obtaining from the village a drainage and grading permit. Regulated activity defined. Unless it is exempted in Subsection C below, any development, redevelopment, construction, grading or landscaping is considered a regulated activity if it is reasonably expected to: (1) Cause an increase in the ground surface elevation; (2) Cause an obstruction in the flow of stormwater runoff from any property; (3) Cause a change in the direction or location of stormwater runoff from a property; or (4) Disturb 200 square feet or more of the ground surface. Development, redevelopment, construction, grading or landscaping that disturbs less than 200 square feet, but is part of a larger common project that, as a whole, disturbs 200 square feet or more, is considered a regulated activity. Exemptions from permit requirement. Projects that consist solely of one or more of the following activities shall be exempt from the requirement to obtain a drainage and grading permit pursuant to this Section : (1) Performing maintenance activities; (2) Changing the discharge direction of a downspout; 2

3 (3) Gardening and/or planting bushes and trees, provided that the activity does not obstruct the flow of stormwater runoff or cause a change in the direction or location of stormwater runoff from any property; (4) Removing dead or dying vegetation; (5) Performing other activities determined in writing by the code official to have a negligible impact on the quantity, velocity, or direction of stormwater runoff from a property; or (6) Any activity in the waters of Lake Michigan PERMIT PROVISIONS Permit fee required. No drainage and grading permit shall be issued pursuant to this subchapter unless a drainage and grading fee is paid by the applicant. The drainage and grading permit fee shall be in the amount established in the annual fee ordinance. Deposit. All drainage and grading permits for major projects shall be subject to deposit of a late work fee escrow, unless the major project is required to submit such a deposit pursuant to this chapter. Expiration of permit. A drainage and grading permit shall expire if the work covered by the drainage and grading permit: (1) is not commenced within six months after the issuance of the drainage and grading permit; (2) is suspended or abandoned for a period of six months or more; or (3) is not completed within six month for minor projects, or 12 months for major projects. (D) Permit extensions. An extension must be applied for prior to the expiration of the drainage and grading permit for which extension is sought, and may be granted by the code official because of delays resulting from strikes, fire, windstorm or other circumstances beyond the applicant s control; provided, however, that no single extension shall exceed three (3) months for minor projects and six (6) months for major projects, and the total duration of all extensions granted shall not exceed twelve (12) months. If no such extension is granted and the work is not completed, the applicant shall be required to apply for a new drainage and grading permit under the provisions of this code. No permit fees shall be refunded because of the expiration of any drainage or grading permit pursuant to the provisions of this section. Fees for all extensions shall be in amounts established by the Board of Trustees in the annual fee ordinance from time to time. 3

4 (E) Permit requirements. (1) Any person issued a drainage and grading permit must retain at the work site, throughout the duration of the regulated activity, the engineering plans bearing the approval stamp of the code official. (2) The code official may require additional or alternate soil erosion and sediment control measures beyond those specified on the approved engineering plans, based on site specific considerations and the effectiveness of the installed control measures. (3) A foundation survey shall be submitted upon completion of every building foundation. The foundation survey shall include dimensions from the as-built foundation to each property line as well as the as-built top-of-foundation elevation, including all steps and foundation openings. (4) An as-built plan shall be submitted upon completion of every regulated activity. For major projects, the as-built plans shall be submitted with a signed statement by a licensed professional engineer that the project was completed in substantial conformance with the approved engineering plans. (5) A certificate of occupancy shall not be issued and the deposit shall not be returned, if applicable, until the code official has approved the as-built plans and completed a final inspection PERMIT APPLICATION REQUIREMENTS All applications for drainage and grading permits shall be submitted on forms provided by the code official, in a number of copies as the code official shall require, and shall include the following: Documentation demonstrating that the applicant has an ownership interest in the subject property, or written authorization by the property owner to proceed with the regulated activity. A plat of survey for the subject property. Engineering plans showing all aspects of the regulated activity. The engineering plans shall include: (1) A north arrow; (2) A drawing scale; (3) A benchmark and datum, which benchmark for major projects shall be referenced to NAVD88; (4) The property lines for the subject property; 4

5 (5) All easements recorded against or affecting the subject property; (6) Existing and proposed ground elevations on the subject property and extending 10 feet beyond the limits of the proposed regulated activity for a minor project, or 10 feet beyond the limits of the subject property for a major project. One-foot contour intervals shall be shown for all projects. When, in the judgement of the code official, one-foot contour intervals are insufficient to show the drainage patterns, 0.5-foot contour intervals shall be shown; (7) Buildings and other structures located on the subject property; (8) Village sewers and water mains located on or adjacent to the subject property; (9) Private storm drains; (10) Utility service lines; (11) Existing and proposed trees and shrubs; (12) Existing and proposed top-of-foundation elevations; (13) Existing and proposed lowest floor elevations; (14) Locations and elevations of existing and proposed downspouts, foundations, and window wells on the subject property; (15) Locations and elevations of downspouts, foundations, and window wells on adjacent properties within 10 feet of the lot line; (16) Existing and proposed impervious areas; (17) Existing and proposed pervious or porous pavements; (18) Areas of temporary ground disturbance; (19) Stockpile locations for spoil materials; (20) Soil erosion and sediment control measures; (21) Specifications for seeding or other methods of site stabilization; (22) Details of construction; (23) Dimensions of the proposed regulated activity; and (24) Signature and seal of a licensed professional engineer. (D) All applicable consultations, waivers, approvals, and permits from Federal, State, and local authorities. 5

6 (E) (F) (G) The site-specific seasonal high groundwater elevation, as determined by a qualified professional engineer, if the regulated activity lowers the lowest floor elevation of the previous or pre-existing building. Detention calculations, prepared by a licensed professional engineer, if applicable. Depressional storage area calculations, prepared by a licensed professional engineer, if applicable DRAINAGE AND GRADING STANDARDS General standards. (1) All regulated activities shall meet or exceed the applicable minimum standards of federal, State, regional, or other local agencies having jurisdiction over the work governed by the permit. (2) No regulated activity shall be allowed to alter the ground surface such that runoff will be diverted onto or detained on an adjacent property that the permittee does not have the right to use. (3) No regulated activity shall be allowed to significantly alter existing drainage patterns or discharge concentrated stormwater runoff onto an adjacent property. (4) All downspouts shall discharge onto the ground surface, except that downspouts in separate sewer areas may be directly connected to a storm sewer in order to prevent an adverse impact on an adjacent property. Where downspouts discharge onto the ground surface, the discharge shall be allowed to flow overland to a private storm drain that is connected to a village storm sewer or combined sewer, provided the overland flow distance is at least 10 feet. (5) Concentrated discharges to the ground surface, such as those from storm drains, downspouts, and sump pumps, shall discharge toward established flow paths in order to minimize the risk to adjacent properties of flooding, erosion, and other drainage hazards. No concentrated discharge created on or after November 1, 2016 shall be constructed within 25 feet of a village sidewalk or 10 feet of an adjacent property line, except in cases where the owner of the subject property has an ownership interest in, or an easement on, the adjacent property. (6) No pavement created on or after November 1, 2016 shall be constructed within two feet of a property line, except pavement necessary for authorized driveway access from the property to a public or private right-of-way, or in cases where the owner of the subject property has an ownership interest in, or an easement on, the adjacent property. (7) Depressional storage areas that will be filled or drained by a regulated activity shall be replaced on the subject property as a new depressional storage area or as part of a stormwater detention system. 6

7 (8) Ground slopes shall be no steeper than 25 percent, unless permanent ground treatments that do not require mowing are used. Soil erosion and sediment control standards. (1) Acceptable control measures include, but are not limited to: silt fence, ditch checks, erosion control blanket, stabilized construction entrances, and inlet protection. Control measures shall meet the minimum standards and specifications of the Illinois Urban Manual, unless otherwise modified by the code official pursuant to the applicable procedures of this code. If the minimum standards and specifications of the Illinois Urban Manual conflict with the other provisions of this code, the requirements that provide the greatest protection to the public, as determined by the code official, shall govern and control. (2) Soil disturbance shall be conducted in such a manner as to minimize erosion. Areas that are not to be disturbed shall be protected from construction equipment or other disturbance until final stabilization is achieved. (3) Soil stabilization measures shall consider the time of year, site conditions, and the use of temporary or permanent control measures. (4) Adjacent properties shall be protected from erosion and sedimentation. Velocity dissipation devices shall be placed at concentrated discharge locations as necessary to prevent erosion. (5) Sediment control measures shall be installed prior to the disturbance of upland areas. (6) Stabilization of disturbed areas shall be initiated immediately whenever any clearing, grading, excavating or other earth disturbing activities have permanently ceased on the site, or temporarily ceased on the site for a period exceeding seven days. (7) All temporary control measures shall be removed within seven days after final stabilization of the site is achieved, or after the temporary measures are no longer necessary, as determined by the code official. Trapped sediment shall be removed and disturbed areas shall be permanently stabilized. Stormwater detention standards. (1) Stormwater detention shall be required on the subject property for the following regulated activities: (a) (b) Construction of any new residence, including construction of a new residence on an existing foundation; Construction of any new commercial building; and 7

8 (c) Construction of a substantial alteration, as this term is defined in Chapter 153 of this code, as amended. (2) The required volume of stormwater detention shall be determined using the Metropolitan Water Reclamation District of Greater Chicago s Modified Rational Method with the data and design conditions listed below: (a) (b) (c) (d) The rainfall intensity shall be based on the Illinois State Water Survey, Bulletin 70 Northeast Illinois sectional rainfall intensity, published in The allowable release rate for existing and proposed conditions shall be based on a runoff coefficient of 0.15 and the rainfall intensity for a threeyear storm event. The composite runoff coefficient for the proposed conditions shall be based on the maximum impermeable lot coverage allowed by Chapter 153 of this code, as amended. The required volume of stormwater detention shall be the difference in the storage volume calculated for existing and proposed conditions for a 100- year storm event. (3) Stormwater storage volume located within the void space of best management practices, such as a rain garden or the aggregate base of permeable pavement, may be credited toward the required stormwater detention volume according to the following standards: (a) (b) (c) The maximum void space shall be 36 percent for gravel and 25 percent for engineered soil. No more than 25 percent of the required stormwater detention volume may be provided within the aggregate base of permeable pavement. No more than 25 percent of the required stormwater detention volume may be provided within a rain garden. (4) The volume of depressional storage areas that will be filled or drained by a regulated activity may be replaced as part of a stormwater detention system. (5) All runoff from the new impervious areas of the site shall be routed to the stormwater detention facility. The system shall convey the 100-year peak rate of runoff from the impervious areas to the facility, with a minimum of 6 inches of freeboard against overflowing off-site. 8

9 (D) Building elevation standards. (1) The first floor elevation for any new single-family residential construction on a previously developed property shall not exceed the first floor elevation of the previous residence. (2) The lowest floor elevation for any new building construction which includes a basement, cellar or crawlspace on a previously developed property shall not be lower than at least 18 inches above the seasonal high groundwater elevation. The seasonal high groundwater elevation for the subject property shall be determined by a qualified professional DISCLAIMER OF LIABILITY The degree of protection from drainage hazards required by these regulations is considered reasonable for regulatory purposes and is based on scientific and engineering considerations; however, on occasion, extreme storms may occur and result in greater flood heights and drainage hazards. Furthermore, flood heights or drainage hazards may be increased by other man-made or natural causes. These provisions do not imply that land outside of mapped flood hazard areas, or that uses permitted within such areas will be free from flooding or drainage hazards. These provisions shall not create liability on the part of the village, nor any officer or employee thereof, for any damage that results from reliance on these regulations, activities for which a permit is issued pursuant to this subchapter, or any administrative decision lawfully made thereunder. SECTION 3: Effective Date. This Ordinance shall be in full force and effect upon its passage, approval, and publication in pamphlet form in the manner provided by law, but shall not be applicable to any matter for which a complete application for a building permit has been submitted to and received by the Village prior to November 1, For purposes of this section, a "complete application" shall mean an application that: (1) has been fully executed by all appropriate parties and (2) includes all required and necessary supporting documentation. Passed this 17 th day of October, AYES: Lien, Lennon, Konen, Potter, Shadek, Winslow NAYS: None ABSENT: ABSTAIN: Approved this 17 th day of October,