Proposals for new subdivisions, manufactured home parks, travel trailer parks, planned unit developments (PUDs) and additions to manufactured home parks and additions to subdivisions shall include base flood or 100-year frequency flood elevation data and floodway delineations. Where this information is not available from existing adopted study, the applicant’s engineer shall be responsible for calculating the base flood or 100-year floodway delineation per the definition in § 152.002 and submitting it to the State Water Survey and IDNR-OWR for review and approval as best available regulatory data. At a minimum, the following material shall be submitted for engineering review for all projects including or in close proximity to regulatory floodplain:
(A) FIRM with scaled project limits.
(B) FIS profile with project limits.
(C) The grading plan, topographic workmap or a floodplain exhibit and the preliminary and final plats shall include all of the following:
(1) Regulatory floodplain shall be delineated from the current FEMA FIRM, FBFM or LOMR.
(2) Regulatory Floodway as delineated on the current effective regulatory maps scaled using references common to both the map and the plan.
(3) Existing BFE by elevation (determined by FIS profile, flows and data; elevation or depth from AH or AO zones; or detailed site specific flood study).
(4) Proposed BFE by elevation (determined by detailed flood study).
(5) All plats shall list all lots lying inside the SFHA based on FEMA’s current effective FIRM and as being permit restricted until the LOMR is approved and copy provided to the village.
(6) Village benchmark used and correlation equation to FEMA datum (NAVD 1988).
(7) All existing and/or proposed buildings and structures with lowest floor (including basements) and openings (walk-out and look-out) locations and elevations indicated within the project limits and within 100 feet offsite.
(8) Existing and proposed contours and spot elevations.
(9) Existing and proposed drainage and utility easements.
(10) Erosion and sedimentation control plan/stormwater pollution prevention plan.
(D) The plan set shall also include:
(1) Cross section locations.
(2) Ten-year and 100-year existing and proposed flood elevations.
(E) The detailed site specific flood study shall include, but not be limited to:
(1) Hydrologic analysis (input and output) using TR-20 or Pond Pack as developed by Haestad Methods, Inc. If an existing regulatory model uses the ACOE computer model, HEC-1, that model can be used.
(2) Drainage area exhibit utilizing best available contour information (with location of time of concentration path, soil types and runoff coefficients).
(3) Existing and proposed hydraulic analysis (input and output) using HEC-2, HECRAS, or WSP-2.
(4) Existing and proposed model cross sections.
(5) Existing and proposed detailed cross sections.
(6) Tabular summary of 100-year flood elevations and discharges for existing and proposed conditions.
(F) Where compensatory storage is permitted, the calculation shall include:
(1) Cross-sections with existing and proposed ten-year and 100-year elevations labeled.
(2) Areas of cut and fill above and below the ten-year elevation.
(3) Tabular calculation of total fill, required compensatory storage and provided compensatory storage.
(G) Design computations shall be made by the Design Engineer for all phases of the project when such computations are required to facilitate review by the Village Engineer. Said computations shall be neat and legible and in a form considered acceptable by the Village Engineer. Said computations shall include, but not necessarily be limited to those listed in this section of the chapter.
(H) Performance security as required by the village.
(I) Maintenance and monitoring plan as required by the village.
(J) Copy of correspondence and permits relating to floodplain areas and/or required by federal or state law, including, but not limited to those issued by FEMA, IDNR-OWR and ACOE (Section 404).
(Ord. 3187, passed 1-22-19) Penalty, see § 152.999