(a) Permitted development. In SFHAs or floodplains where no regulatory floodways have been identified and no base flood elevations have been established by FEMA, and including SFHAs or floodplains that drain more than one square mile, no development shall be permitted unless the cumulative effect of the development proposal, when combined with all other existing and anticipated uses and structures, shall not significantly impede or increase the flow and passage of floodwaters nor significantly increase the base flood elevation.
(b) Development permit. No person, firm, corporation or governmental body not exempted by state law shall commence any development in a SFHA or floodplain without first obtaining a development permit therefor from the building commissioner.
(c) Application. Application for a development permit shall be made on a form provided by the building commissioner. The applicant shall submit a completed application to the building commissioner and forward a copy of such application to the village engineer. The application shall be accompanied by drawings of the site, drawn to scale, showing property line dimensions, existing grade elevations and all changes in grade resulting from excavation or filling, sealed by a licensed engineer, architect or surveyor; the location and dimensions of all buildings and additions to buildings; and the elevation of the lowest floor (including basement) of all proposed buildings subject to the requirements of § 9-101. The building commissioner shall determine, and the applicant shall submit, an appropriate application fee, taking into account the village engineer's cost of review and other village expenses incurred in issuing the development permit. The application shall also include the following information:
(1) A detailed description of the proposed activity, its purpose and intended use;
(2) Site location (including legal description) of the property, drawn to scale, on the regulatory floodway maps, indicating whether it is proposed to be in an incorporated or unincorporated area;
(3) Anticipated dates of initiation and completion of activity;
(4) Plans of the proposed activity shall be provided which include as a minimum:
A. A vicinity map showing the site of the activity, name of the waterway, boundary lines, names of roads in the vicinity of the site, graphic or numerical scale and north arrow;
B. A plan view of the project and engineering study reach showing existing and proposed conditions, including without limitation principal dimensions of the structure or work, elevations in NAVD 88, adjacent property lines and ownership, drainage and flood control easements, distance between proposed activity and navigation channel (when the proposed construction is near a commercially navigable body of water), floodplain limit, location and orientation of cross-sections, north arrow and a graphical or numerical scale; and
C. Cross-section views of the project and engineering study reach showing existing and proposed conditions including principal dimensions of the work as shown in plan view, existing and proposed elevations, normal water elevation, ten-year frequency flood elevation, 100-year frequency flood elevation and graphical or numerical scales (horizontal and vertical);
(5) Engineering calculations and supporting data shall be submitted showing that the proposed work will meet the criteria of this § 9-100; and
(6) Any and all other federal, state and local permits or approvals that may be required for this type of development.
(d) Comparison of elevations. Based on the best available existing data according to the Illinois State Water Survey's Floodplain Information Repository, the village engineer shall compare the elevation of the site to the base flood elevation. Should no elevation information exist for the site, the developer's engineer shall calculate the elevation pursuant to the requirements of § 9-97(f). Any development located on land that can be shown to have been higher than the base flood elevation as of the site's first FIRM identification is not in the SFHA and, therefore, not subject to the requirements of this article XIV. The village engineer shall forward to the building commissioner documentation of the existing ground elevation at the development site and certification that this ground elevation existed prior to the date of the site's first FIRM identification.
(e) Other permit requirements. The applicant shall provide to the building commissioner and to the village engineer copies of all other federal, state and local permits, approvals or permit-not-required letters that are required for this type of activity. The building commissioner shall be responsible for obtaining from the applicant all other federal, state and local permits, approvals or permit-not-required letters that are required for this type of activity. The building commissioner shall not issue a development permit unless all other federal, state and local permits have been obtained.
(f) No public health threat. No development in the SFHA, when a regulatory floodway has not been determined, shall create a damaging or potentially damaging increase in flood heights or velocity or otherwise threaten the public health, safety or welfare.
(g) Standards. Within all riverine SFHAs, when the regulatory floodway has not been determined, the following standards shall apply.
(1) Calculation of regulatory floodway. The developer shall have a registered professional engineer state in writing and show through supporting plans, calculations and data that the project meets the engineering requirements of §§ 9-99(g)(1) through 9-99(g)(10) for the entire floodplain as calculated under the provisions of §§ 9-97(e) and (f). As an alternative, the developer may have an engineering study performed to determine a floodway and submit that engineering study to OWR for acceptance as a regulatory floodway. Upon acceptance of such regulatory floodway by OWR, the developer then shall demonstrate that the project meets the requirements of § 9-99 for the regulatory floodway as defined in § 9-95.
(2) OWR permit. No building permit shall be issued unless the applicant first obtains a permit or written documentation that a permit is not required, from OWR; provided, however, that no permit from OWR shall be required if OWR has delegated permit responsibility to the village pursuant to 17 Ill. Admin. Code § 3708 for regulatory floodways, pursuant to OWR’s statewide permit entitled “Construction in Floodplains with No Designated Floodways in Northeastern Illinois.”
(3) Dam safety permits. Any work involving the construction, modification or removal of a dam or an on-stream structure to impound water as defined in § 9-95 shall obtain a OWR dam safety permit or as defined in § 9-95 a permit-not-required letter prior to the start of such construction, modification or removal. If the building commissioner finds a dam that does not have a OWR permit, the building commissioner shall immediately notify the Dam Safety Section of OWR. If the building commissioner finds a dam that is believed to be in an unsafe condition, the building commissioner shall immediately notify the owner of the dam, if known, OWR, the Dam Safety Section of OWR and the Illinois Emergency Services and Disaster Agency (ESDA).
(4) No review required. The following activities may be permitted without a registered professional engineer's review or calculation of a base flood elevation and regulatory floodway; provided, however, that such activities shall meet the other requirements of this article XIV:
A. Underground and overhead utilities:
1. That do not result in any increase in existing ground elevations;
2. That do not require the placement of aboveground structures in the floodway;
3. When, in the case of underground stream crossings, the top of the pipe or encasement is buried a minimum of three feet below the existing stream bed; and
4. When, in the case of overhead utilities, no supporting towers are placed in the watercourse and are designed in such a fashion as not to catch debris.
B. Storm and sanitary sewer outfalls that:
1. Do not extend riverward or lakeward of the existing adjacent natural bank slope;
2. Do not result in an increase in ground elevation; and
3. Are designed so as not to cause stream bank erosion at the outfall location.
C. Construction of shoreline and streambed protection:
1. That does not exceed 1,000 feet in length or two cubic yards per lineal foot of stream bed;
2. When materials are not placed higher than the existing top of bank; or
3. When materials are placed so as not to reduce the cross-sectional area of the stream channel by more than 10%.
D. Temporary stream crossings in which:
1. The approach roads will be one-half foot or less above natural grade;
2. The crossing will allow stream flow to pass without backing up the water above the stream bank vegetation line or above any drainage tile or outfall invert;
3. The top of the roadway fill in the channel will be at least two feet below the top of the lowest bank;
4. All disturbed stream banks will be seeded or otherwise stabilized as soon as possible upon installation and again upon removal of construction; and
5. The access road and temporary crossings will be removed within one year after authorization.
E. The construction of light poles, sign posts and similar structures;
F. The construction of sidewalks, driveways, athletic fields (excluding fences), patios and similar surfaces that are built at grade;
G. The construction of properly anchored, unwalled, open structures such as playground equipment, pavilions and carports built at or below existing grade that would not obstruct the flow of flood waters;
H. The placement of properly anchored buildings not exceeding 70 square feet in size and ten feet in any one dimension;
I. The construction of additions to existing buildings that do not increase the first floor area by more than 20%, that are located on the upstream or downstream side of the existing building, and that do not extend beyond the sides of the existing building that are parallel to the flow of flood waters; and
J. Minor maintenance dredging of a stream channel when:
1. The affected length of stream is less than 1,000 feet;
2. The work is confined to re-establishing flows in natural stream channels; or
3. The cross-sectional area of the dredged channel conforms to that of the natural channel upstream and downstream of the site.
(5) Flood carrying capacity. The flood carrying capacity within any altered or relocated watercourse shall be maintained.
(h) Compensatory storage. Whenever any portion of a floodplain is authorized for use, the volume of space that will be occupied by the authorized fill or structure below the base flood elevation shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the base flood elevation. The excavation volume shall be at least equal to one and one-half times the volume of storage lost due to the fill or structure. In the case of streams and watercourses, such excavation shall be made opposite or adjacent to the areas so filled or occupied. All floodplain storage lost below the existing ten-year flood elevation shall be replaced below the proposed ten-year flood elevation. All floodplain storage lost above the existing ten-year flood elevation shall be replaced above the proposed ten-year flood elevation. All such excavations shall be constructed to drain freely and openly to the watercourse.
(Ord. No. 2021-16-3512)