NR 116.07(4)(e)(e) Previous floodplain studies. If differences exist between a study previously approved by the department and the contractor’s calculated hydraulic floodways or flood profiles, the study contractor shall document justification and obtain departmental approval for these differences. Where the contractor’s study differs from existing flood profiles or hydraulic floodways for adjacent communities, verification of the differences will be necessary for department approval of the hydraulic analysis.
NR 116.07(4)(f)(f) Calculation of the regional flood profile. The regional flood profile and changes to that profile caused by development in the floodplain, as determined by the hydraulic model, shall be calculated to the nearest 0.01 foot.
NR 116.07(4)(g)(g) Adequacy of the hydraulic model. The following factors shall be considered by the department to determine the adequacy of the hydraulic model and the regional flood profile. Upon written request by the department the study contractor shall submit written justification for the following factors:
NR 116.07(4)(g)1.1. Cross section spacing.
NR 116.07(4)(g)2.2. Differences in energy grade.
NR 116.07 NoteNote: Significant differences in the energy grade from cross section to cross section are an indication that cross sections should be more closely spaced or that other inaccuracies exist in the hydraulic model.
NR 116.07(4)(g)3.3. Methods for analyzing the hydraulics of structures such as bridges and culverts.
NR 116.07(4)(g)4.4. Lack of flow continuity.
NR 116.07(4)(g)5.5. Use of gradually varied flow model.
NR 116.07 NoteNote: In certain circumstances, rapidly varied flow techniques shall be used in combination with a gradually varied flow model such as weir flow over a levee or dike, flow through the spillway of a dam or special applications of bridge flow.
NR 116.07(4)(g)6.6. Manning’s “n” values.
NR 116.07(4)(g)7.7. Calibration of the hydraulic model with past flood events.
NR 116.07(4)(h)(h) Special applications. The methods defined in par. (c) shall be used except in special cases, including circumstances where sediment transport, 2 dimensional flow or valley storage affects the accuracy of the hydraulic model. Where the standard step method is unwarranted, the department shall approve the method used for establishing the final water surface profile.
NR 116.07(4)(i)(i) Base mapping. In the preparation of a floodplain zoning map to be used by the municipality, the study contractor shall use the best available mapping to delineate floodplain limits.
NR 116.07(4)(j)(j) Final report. A narrative report shall accompany the maps and profiles and shall include the following:
NR 116.07(4)(j)1.1. Purpose of the study and description of the study area.
NR 116.07(4)(j)2.2. Coordination with other agencies.
NR 116.07(4)(j)3.3. Data collection.
NR 116.07(4)(j)4.4. Past flooding.
NR 116.07(4)(j)5.5. Engineering methods including a detailed description of the methodology used for hydrology, hydraulics and any special applications used in this study.
NR 116.07(4)(j)6.6. A floodway data table showing cross sections, drainage area, distance between cross sections, floodway top width, discharge, cross sectional area, mean velocity and regional flood elevation.
NR 116.07(4)(j)7.7. Previous studies on the same watercourse.
NR 116.07(4)(j)8.8. An appendix which includes:
NR 116.07(4)(j)8.a.a. Drainage basin maps.
NR 116.07(4)(j)8.b.b. Precipitation maps.
NR 116.07(4)(j)8.c.c. Pertinent photographs.
NR 116.07(4)(j)8.d.d. Soil and vegetation maps.
NR 116.07(4)(j)8.e.e. Sample calculations of the hydrologic analyses including all unit hydrographs.
NR 116.07(4)(j)8.f.f. Stream flow records.