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PERMITS
§ 155.015 CONSTRUCTION PERMITS IN THE FLOODWAY.
   (A)   I.C. 14-28-1-22, requires Natural Resources Commission approval of any construction in a floodway, and of any works for flood control. This includes bridges, dams, levees, dikes, floodwalls, wharves, piers, dolphins, booms, weirs, bulkheads, jetties, groins, excavations, fills or deposits of any kind, utility lines, or any other building, structure or obstruction; also, any ditch work (new construction, deepening or modification) within 1/2 mile of a public freshwater lake of 10 acres or more in area.
   (B)   The approval of the Natural Resources Commission, in writing, must be obtained before beginning construction. Applications for approval should be submitted to:
Department of Natural Resources
Division of Water
Indianapolis, Indiana
   (C)   All applications should be made on the standard application form provided by the Commission and should be accompanied by plans, profiles, specifications and other data necessary for the Commission to determine the effect of the proposed construction upon the floodway and on flood control in the state.
   (D)   Application made to and approval granted by the Natural Resources Commission does not in any way relieve the owner of the necessity of securing easements or other property rights, and permits and/or approvals from affected property owners and local, state and federal agencies.
   (E)   The engineering staff of the Division of Water is available to discuss and offer suggestions regarding requirements in the design of structures in floodways. High water marks have been set on many of the streams in the state, and information is available from the Division of Water on actual and/or potential flooding. Information regarding benchmarks set to Mean Sea Level Datum, General Adjustment of 1929, is available from the Division of Water, Surveying and Mapping Section.
   (F)   Applications are considered by the Commission at regular meetings usually held each month. After the application and plans have been approved by the Commission, a certificate of approval is forwarded to the applicant.
   (G)   A fee is charged by the Commission for approvals under I.C. 14-28-1-22. Unless stated otherwise in the approval, construction is considered to be a permanent development, and no renewals of the approval are necessary, except in the cases where temporary approvals are granted for temporary construction. The right is reserved to require additional data where necessary.
(Ord. 1995-10 § VI, passed 10-13-1995)
§ 155.016 INFORMATION REQUIREMENTS.
   The following information and data provided by an Indiana licensed professional engineer engaged in storm drainage design shall be submitted to the Board at the time of application for a building permit for any development, redevelopment or new construction on real estate which lies within the regulated area:
   (A)   Topographic and soils maps. A soils map of the proposed development indicating soils names and their hydrologic classification must be provided when Natural Resource Conservation Service (NRCS) hydrologic methods are used. In addition, either cross-sections at 100-foot intervals or a topographic map of the land to be subdivided and adjoining land whose topography may affect the layout or drainage of the development must be provided. The contour intervals shall be 1 foot when slopes are less than 4%, and shall be 2 feet when the slope exceeds 4%. On this map, the following shall be shown:
      (1)   The location of streams and other floodwater runoff channels, the extent of the floodplains at the established 100-year flood elevation where available (regulatory floodway), and the limits of the floodway, all properly identified;
      (2)   The normal shoreline of lakes, ponds, swamps and detention basins, their floodplains, and lines of inflow and outflow, if any;
      (3)   The location of regulated drains (regulated drains were previously known as legal drains), farm drains, inlets and outfalls, if any of record;
      (4)   Storm, sanitary and combined sewers and outfalls, if any of record;
      (5)   Septic tank systems and outlets, if any of record; and
      (6)   Seeps, springs, flowing and other wells, that are visible or of record.
   (B)   Preliminary drainage plan. A compre- hensive plan, in preliminary form (or in combined preliminary and final form), designed to handle safely the storm water runoff and to detain the increased storm water runoff, must be provided. The plan shall provide or be accompanied by maps or other descriptive materials indicating the feasibility of the drainage plan and showing the following:
      (1)   The extent and areas of each watershed affecting the design of detention facilities as shown on U.S.G.S. quadrangle maps or other more detailed maps as required by the Board;
      (2)   The preliminary layout and design of proposed storm sewers, the outfall and outlet locations and approximate elevations, the receiving stream or channel and its 100-year return period water elevation;
      (3)   The location and design of the proposed street system, especially including depressed pavements used to convey or temporarily store overflow from the heavier rainstorms, and the outlets for the overflow;
      (4)   The locations, cross-sections and profiles of existing streams and floodplains to be maintained and new channels to be constructed;
      (5)   The locations, materials, elevations, waterway openings and the basis for design of proposed culverts and bridges;
      (6)   Existing detention ponds and basins to be maintained, enlarged, or otherwise altered and new ponds or basins to be built and the basis of their design;
      (7)   The estimated depth and amount of storage required in the new ponds or basins;
      (8)   The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed; and
      (9)   Any interim plan which is to be incorporated into the development, pending completion of the development and the final drainage plan.
   (C)   Valley cross-section. One or more typical cross-sections must be provided showing all existing and proposed channels or other open drainage facilities carried to a point above the 100-year high water elevation; showing the elevation of the existing land and the proposed changes thereto, together with the high water elevations expected from the 100-year storm under the controlled conditions called for by this chapter; and showing the relationship of structures, streets and other facilities.
   (D)   Site plan. A plan drawn to scale showing dimensions of the site with existing and proposed storm drainage facilities must be provided.
   (E)   Final drainage plans. Upon approval of the preliminary drainage plans by the Board, final drainage plans shall be submitted to the Board. The final plans shall be stamped by an engineer registered in the State of Indiana, and shall provide or be accompanied by calculations, maps and/or other descriptive material showing the following:
      (1)   The extent and area of each watershed tributary to the drainage channels in the development;
      (2)   The street storm sewers and other storm drains to be built, the basis of their design, outfall and outlet locations and elevations, the receiving stream or channel and its high water elevation, and the functioning of the drains during high water conditions;
      (3)   The parts of the proposed street system where pavements are planned to be depressed sufficiently to convey or temporarily store overflow from storm sewers and over-the-curb runoff resulting from the heavier rainstorms, and the outlets for that overflow;
      (4)   Existing streams and floodplains to be maintained, and new channels to be constructed, their locations, cross-sections and profiles;
      (5)   Proposed culverts and bridges to be built, their locations, materials, elevations, waterway openings and basis of their design;
      (6)   Existing detention basins and ponds to be maintained, enlarged or otherwise altered, and new basins or ponds to be built and the basis of their design;
      (7)   The estimated location and percentage of impervious surfaces existing and expected to be constructed when the development is completed;
      (8)   The slope, type and size of all sewers and other waterways; and
      (9)   For all detention basins, a plot or tabulation of storage volumes with corresponding water surface elevations and a plot or tabulation of the basin outflow rates for those water surface elevations.
   (F)   Submittal and consideration of plans.  
      (1)   Preliminary and final drainage plans and/or construction plans shall be submitted to the Board 20 days prior to its regularly scheduled meeting. All preliminary plans, final plans, and/or construction plans in compliance with the standards of this chapter shall be approved by the Board. The Board and/or the County Surveyor shall stamp the approval on a copy of the plans and deliver the same to the applicant. The Board shall approve or disapprove any preliminary plans, final plans and/or construction plans within 60 days of submission unless the applicant consents to a continuance or extension. All approvals and disapprovals with written reasons shall be incorporated into the Board minutes.
      (2)   The town is authorized to review engineering summaries of projects and based upon the same grant exemptions from any and all requirements of this chapter and/or waive any requirements of this chapter. Any applicant may appeal the decision of the engineer to the Board, which shall also be authorized to grant exemptions from any and all requirements of this chapter and/or waive any requirements of this chapter at its discretion.
(Ord. 1995-10 § VII, passed 10-13-1995)
§ 155.017 DETERMINATION OF RUNOFF QUANTITIES.
   (A)   Runoff quantities shall be computed for the area of the parcel under development plus the area of the watershed flowing into the parcel under development.
   (B)   The quantity of runoff which is generated as the result of a given rainfall intensity may be calculated as follows:
      (1)   For areas up to and including 200 acres, the rational method may be used.
         (a)   In the rational method, the peak rate of runoff, Q, in cubic feet per second is computed as:
         Q = CIA
where C=runoff coefficient, representing the characteristics of the drainage area and defined as the ratio of runoff to rainfall; I=average intensity of rainfall in inches per hour for a duration equal to the time of concentration (tc) for a selected rainfall frequency; and A=tributary drainage area in acres.
         (b)   Guidance to selection of the runoff coefficient C is provided by Appendix A, Tables 1 and 2 which show values for different types of surface and local soil characteristics. The composite C-value used for a given drainage area with various surface types shall be the weighted average value for the total area calculated from a breakdown of individual areas having different surface types.
         (c)   Appendix A, Table 3 provides runoff coefficients and inlet times for different land use classifications. In the instance of undeveloped land situated in an upstream area, a coefficient or coefficients shall be used for this area in its present or existing state of development.
         (d)   Rainfall intensity shall be determined from data shown in Appendix A, Table 6. The time of concentration (tc) to be used shall be the sum of the inlet time and flow time in the drainage facility from the most remote part of the drainage area to the point under consideration. The flow time in the storm sewers may be estimated by the distance in feet divided by velocity of flow in feet per second.
         (e)   The velocity shall be determined by the Manning equation.
         (f)   Inlet time is the combined time required for the runoff to reach the inlet of the storm sewer. It includes overland flow time and flow time through established surface drainage channels such as swales, ditches and sheet flow across such areas as lawns, fields, and other graded surfaces. It may be computed by using Appendix B, Figure 1.
      (2)   The runoff rate for areas in excess of 200 acres shall be determined by methods described in § 155.076.
(Ord. 1995-10 § VIII, passed 10-13-1995)
§ 155.018 AMOUNT OF RUNOFF TO BE ACCOMMODATED BY VARIOUS PARTS OF DRAINAGE FACILITY.
   (A)   The drainage facility shall be such that all habitable structures are free from a 100-year flood. Also, all land alterations shall be accomplished so as to prevent damage to adjoining property. Provision must be made for receiving and conveying off-site runoff through the site and for preserving existing drainage systems (including field tiles). A natural or surface channel system shall be designed with adequate capacity to convey through the development the storm water runoff from all tributary upstream areas. This bypass channel shall be designed to carry the peak rate of runoff from a 100-year storm, assuming all storm sewers are blocked and that the upstream areas are fully developed.
   (B)   Various parts of a drainage facility must accommodate runoff water as follows:
      (1)   The minor drainage system such as inlets, catch basins, street gutters, swales, sewers and small channels which collect storm water must accommodate peak runoff from a 10-year return period storm. These minimum requirements must be satisfied:
         (a)   The allowable spread of water on collector streets is limited to maintaining 2 clear 10-foot moving lanes of traffic. One lane is to be maintained on local roads, while places can have a water spread equal to 1/2 their width. No reverse crown roadways will be constructed;
         (b)   Open channels carrying peak flows greater than 30 cubic feet per second shall be capable of accommodating peak runoff for a 50-year return period storm within the drainage easement;
         (c)   1.   Culverts shall be capable of accommodating peak runoff from a 50-year return period storm with less than 1 foot of backwater when crossing under a road which is part of the Indiana Department of Transportation rural functional classification system and is classified as a principal or minor arterial or major or minor collector road.
            2.   Driveway culverts shall have a minimum diameter of 12 inches and a minimum length of 20 feet.
      (2)   Major drainage systems are defined in § 155.005 and shall be designed in accordance with Indiana Department of Natural Resources Standards as described in § 155.015.
(Ord. 1995-10 § IX, passed 10-13-1995)
§ 155.019 EASEMENTS.
   (A)   The Drainage Board may, as a prerequisite to issuance of a storm water permit, require the dedication of easements to the town and to owners of other affected lands by the owner of the parcel of land relative to which application for a storm water permit has been made, where necessary to achieve satisfactory present and future drainage of the parcel and the area surrounding the parcel.
   (B)   Provisions concerning these easements are as follows:
      (1)   Easements shall be required for areas that drain greater than 5 acres of storm water runoff which are adjacent to the parcel in question but not under the same ownership.
      (2)   These easements shall be accessible to vehicular traffic.
      (3)   Easements along a public right-of-way shall be contiguous with and accessible from the right-of-way. The granting of a drainage easement to the town does not create a responsibility for the town to maintain the drainage facilities located within the easement area.
      (4)   The town shall be under no obligation to accept a dedication from the subdivider, developer or owner of any of the storm water detention facilities, ponds or areas; but the town, in the exercise of its sole and exclusive discretion, may require the subdivider, developer or owner to so dedicate the facilities, ponds or areas to the town. In the event that no such dedication is required, the subdivider, developer and/or owner shall be required to submit to the town written evidence in the form of covenants, conditions or restrictions that run with and become a charge against the land providing for the perpetual maintenance of the storm water retention facilities, ponds or areas at no cost to the town in form and content acceptable to the town, which covenants, conditions and restrictions the town is hereby authorized to record with the appropriate County Recorder of Deeds as and for permanent evidence of that obligation to maintain.
      (5)   Detention/retention basins shall be constructed within a storm water easement either platted or legally described and recorded as a perpetual storm water easement, a minimum of 20 feet horizontally outside of the design 100-year floodwater elevation of the basin. All detention/retention basins shall be maintained according to original design capacity.
      (6)   Guidelines for minimum easement widths for swales and ditches are provided below. A hydraulic and hydrologic computation must be performed to determine the inundated area of the 25-year storm. The easement must protect the entire 25-year flood area. For drainage areas larger than 5 acres, an analysis must be performed for the 100-year storm event. A 100-year storm event flood line must be added to the 25-year easement restriction. The lowest location of any adjacent structures where water may enter must be outside the 100-year storm event plan view.
         (a)   Residential collector swales.  
            1.   Surface water collector swales within the rear yard and side yard areas of residential subdivisions shall be constructed within a drainage easement possessing a minimum width of 20 feet, with the drainage swale constructed approximately in the middle of the easement.
            2.   Surface water collector swales within commercial and industrial developments will not be required to be constructed within a storm water easement, provided only minimal quantities of off-site surface water flows are required to enter the channel. Minimal quantities shall mean less than 5 acres of land area. Collector swales within commercial and industrial developments which collect 5 acres or more of off-site land area shall be constructed within a storm water easement possessing a minimum width of 20 feet.
         (b)   Open ditches. Existing open ditches which are to be perpetuated through the developing property and newly constructed open ditches shall be placed within a drainage easement of a minimum width of 20 feet from the tops of banks of the channel. All ditches shall be maintained according to original design capacity.
      (7)   (a)   Minimum easement widths for storm drains are as provided below. More stringent requirements for storm water easement size and additional covenants may be made by the Department based upon individual site conditions.
         (b)   Storm drain easement widths are as follows:
 
Depth of Drain, from Finish Grade to Crown
Diameter of Storm Drain
Minimum Easement Width
3 feet or less
15 inches or less
15 feet
More than 3 feet
15 inches or less
20 feet
3 feet or less
Greater than 15 inches
20 feet
More than 3 feet
Greater than 15 inches
25 feet
 
      (8)   An easement for open culverts must be recorded for the 50-year storm event flow areas.
(Ord. 1995-10 § XXIV, passed 10-13-1995)
§ 155.020 PERMIT AND REVIEW FEES.
   The following schedule of fees shall apply to this chapter:
 
Fee Category
Amount
Single-family or 2-family home, agricultural driveway permit fee
$20
Commercial/industrial driveway permit fee
$50
Residential, commercial, and industrial subdivision/individual project drainage plan review fee
$150 or $15 per acre, whichever is greater
 
(Ord. 1995-10 § XX D, passed 10-13-1995)
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