In SFHA or floodplains, (including AE, AO and Unnumbered A Zones) where no floodways have been identified and no base flood or 100-year frequency flood elevations have been established by FEMA, and draining more than a square mile, no development shall be permitted unless the cumulative effect of the proposals, when combined with all other existing and anticipated uses and structures, shall not significantly impede or increase the flow and passage of the flood waters nor significantly increase the base flood or 100-year frequency flood elevation.
(A) Development permit.
(1) No person, firm, corporation or governmental body, not exempted by state law, shall commence any development in a SFHA or floodplain or on property which includes a SFHA or floodplain, without first obtaining a development permit from the Building and Zoning Administrator or the village’s designated representative.
(2) Application for a development permit shall be made on a form provided by the village.
(a) The application shall be accompanied by drawings of the site, drawn to scale showing property line dimensions, and 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 elevations of the lowest floor (including basement) of all proposed buildings subject to the requirements of § 154.10 below.
(b) The application for a development permit 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 designated 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 at 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 principal dimensions of the structure or work, elevations in mean sea level (1929 adjustment) datum or N.G.V.D., adjacent property lines and ownership, drainage and flood control easements, distance between proposed activity and navigation channel (when the proposed construction is in or near a commercially navigable body of water), floodplain limit, location and orientation of cross-sections, north arrow and a graphical or numerical scale;
c. Cross-section views of the project perpendicular to the flow of flood water and engineering study reach showing existing and proposed conditions including principal dimensions of the work as shown in the 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); and
d. A soil erosion and sedimentation control plan for disturbed areas. This plan shall include a description of the sequence of grading activities and the temporary sediment and erosion control measures to be implemented to mitigate their effects. This plan shall also include a description of final stabilization and revegetation measures, and the identification of a responsible party to ensure post-construction maintenance.
(c) Engineering calculations and supporting data shall be submitted showing the proposed work will meet the criteria of division (B) below.
(d) Any and all other federal, state and local permits or approvals that may be required for this type of development.
(3) Based on the best available existing data according to the State Water Survey’s Floodplain Information Repository, the Building and Zoning Administrator or the village’s designated representative shall compare the elevation of the site to the base flood or 100-year frequency flood elevation.
(a) Should no elevation information exist for the site, the developer’s engineer shall calculate the elevation according to § 154.06(D).
(b) Any development located on land that can be shown to have been higher than the base flood elevation of the current flood insurance rate map identification is not in the SFHA and therefore not subject to the requirements of this chapter.
(c) The Building Official shall maintain 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 flood insurance rate map identification.
(4) The Building and Zoning Administrator or the village’s designated representative shall be responsible for obtaining from the applicant copies of all other federal, state and local permits, approvals or permit-not-required letters that may be required for this type of activity. The Building and Zoning Administrator or the village’s designated representative shall not issue the development permit unless all required federal, state and local permits have been obtained.
(B) Preventing increased damages.
(1) No development in the SFHA, where a floodway has not been determined shall create a damaging or potentially damaging increase in flood heights or velocity or a threat to public health, safety and welfare or impair the natural hydrologic and hydraulic functions of the floodway or channel, or impair existing water quality or aquatic habitat. Construction impacts shall be minimized by appropriate mitigation methods as required by this chapter.
(2) Within all riverine SFHAs where the floodway has not been determined, the following standards shall apply:
1. As an alternative, the developer should have an engineering study performed to determine a floodway and submit that engineering study to IDNR/OWR for acceptance as a designated floodway.
(b) A development permit shall not be issued unless the applicant first obtains a permit from IDNR/OWR or written documentation that a permit is not required from IDNR/OWR.
(c) No permit from IDNR/OWR shall be required if IDNR/OWR has delegated permit responsibility to the village pursuant to 92 Ill. Adm. Code Part 708 for designated floodways.
(d) Permits for dams.
1. Any work involving the construction, modification or removal of a dam as defined in § 154.03 or 92 Ill. Adm. Code Part 702 (Rules for Construction of Dams) shall obtain an IDNR/OWR permit prior to the start of construction of the dam.
2. If the Building and Zoning Administrator or the village’s designated representative finds a dam that does not have an IDNR/OWR permit, the Building and Zoning Administrator or the village’s designated representative shall immediately notify the IDNR/OWR.
3. If the Building and Zoning Administrator or the village’s designated representative identifies a dam which is believed to be in an unsafe condition, the Building and Zoning Administrator or the village’s designated representative shall immediately notify the owner of the dam, the IDNR/OWR, and the Illinois Emergency Management Agency (IEMA).
(3) The following activities may be permitted without a registered professional engineer’s review or calculation of a base flood elevation and designated floodway. These activities shall still meet the other requirements of this chapter.
(a) Underground and overhead utilities that:
1. Do not result in any increase in existing ground elevations;
2. Do not require the placement of above ground structures in the floodway; or
3. In the case of underground stream crossings, the top of the pipe or encasement is buried a minimum of three feet below the existing streambed;
4. Overhead utility lines shall be constructed above the estimated 100-year frequency flood elevation or attached above the low chord of an existing bridge (with the permission of the bridge owner). No supporting towers shall be placed in the watercourse, and any such supporting towers shall be designed so as to not catch debris;
5. Disturbance of stream side vegetation shall be kept to a minimum during construction to prevent erosion and sedimentation;
6. A utility crossing carrying material which may cause water pollution as defined by the Environmental Protection Act ILCS Ch. 415, Act 5 (1992 State Bar Edition) shall be provided with shut-off valves on each side of the body of water to be crossed; and
7. All Illinois Commerce Commission, National Electric Safety Codes and federal requirements for clearance must be met.
(b) Storm and sanitary sewer relief 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 erosion at the outfall location.
(c) Construction of shoreline and streambank protection that:
1. Does not exceed 1,000 feet in length;
2. Materials are not placed higher than the existing top of the bank;
3. Materials are placed so as not to reduce the cross-sectional area of the stream channel by more than 10%; and
4. Stabilization utilizing native vegetation and gradual side slopes are the preferred mitigation methods for existing erosion problems. Where high channel velocities, sharp bends or wave action necessitate the use of alternative stabilization measures, soil bioengineering techniques, natural rock or rip-rap are preferred materials. Artificial materials such as concrete, construction rubble and gabions should be avoided unless there are no practicable alternatives.
(d) Temporary stream crossings in which:
1. The approach roads will be a 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. Any fill in the channel shall be non-erosive material, such as rip-rap or gravel;
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 which 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, nor ten feet in any one dimension (e.g., animal shelters and tool sheds);
(i) The construction of additions to existing buildings which do not increase the first floor area by more than 20%, which are located on the upstream or downstream side of the existing building and which do extend beyond the sides of the existing building that are parallel to the flow of flood waters;
(j) Minor maintenance dredging of a stream channel where:
1. The affected length of stream is less than 1,000 feet;
2. The work is confined to reestablishing 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.
(4) The flood carrying capacity shall be maintained within any altered or relocated watercourse.
(5) Compensatory storage.
(a) Whenever any portion of a floodplain is authorized for use, the volume of space which will be occupied by the authorized fill or structure below the base flood or 100-year frequency flood elevation shall be compensated for and balanced by a hydraulically equivalent volume of excavation taken from below the base flood or 100-year frequency flood elevation.
(b) The excavation volume shall be at least equal to one and one-fourths times the volume of storage lost due to the fill or structure.
(c) In the case of streams and watercourses, the excavation shall be made opposite or adjacent to the areas so filled or occupied.
(d) 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 the excavations shall be constructed to drain freely and openly to the watercourse.
(e) A recorded covenant running with the land is required to maintain the compensatory storage volume in areas modified to provide compensatory storage volume.
(Ord. 765, passed 10-20-2004)