(A) Area of jurisdiction. The provisions of this section shall regulate, guide and control all territory in the town as now constituted and as may be added to the town in the future.
(B) Outlets. All outlets into regulated drains or natural watercourses, either direct or indirect, shall meet the standards prepared by the County Surveyor and the requirements set out in this section. Outlets into regulated drains or natural watercourses shall provide a positive unobstructed or unrestrictive conveyance into the system. The following provisions shall be followed:
(1) All conveyances shall terminate into an approved adequate outlet;
(2) All outlets, either open drain or storm sewer, shall extend to the regulated drain or natural watercourse;
(3) All storm sewers shall extend to either a receiving storm sewer system or an open regulated drain or natural surface watercourse as approved by the Hamilton County Surveyor’s Office (hereinafter referred to as “the HCSO”);
(4) Storm sewers shall not outlet into rear yard swales;
(5) Outlets shall not directly discharge onto the ground surface as surface flow:
(6) Underwater discharges shall not be allowed. All discharges into a watercourse, pond or lake shall have the invert at or above the normal pool elevation or normal flow elevation for the receiving system.
(C) Improvements to watercourses.
(1) Whenever a residential subdivision or commercial development constructs improvements upon lands which are traversed by a watercourse, the landowner/developer shall make improvements to the watercourse. These improvements shall consist of the following:
(a) All debris and obstructions within the channel (bank to bank) shall be removed. This shall include but not be limited to logjams and trash.
(b) Clear all trees which are dead and leaning at a 45 degree or greater angle, or trees on which the roots are exposed in the channel and potentially will fall into the stream. In clearing, the trees shall be cut flush with the ground and treated with an EPA-approved brush killer.
(c) All steam bank erosion shall be repaired in an acceptable manner, approved by the Hamilton County Surveyor’s Office.
(D) Improvements. Whenever a residential subdivision or commercial development constructs improvements upon land which is traversed by, or whose property line is within an easement for an open regulated drain, the landowner/developer shall make improvements to the open regulated drain. These improvements shall consist of the following:
(1) All debris and obstructions within the channel (bank to bank) shall be removed. This shall include, but not be limited to, logjams, beaver dams, rocks and trash.
(2) All trees and brush from bank to bank within the channel shall be removed. Trees and brush shall be removed on each side of the drain for a distance of 30 feet, as measured from the top of the bank on both sides of that drain. Trees greater than 18 inches as measured at breast height may be saved if approved by the HCSO inspector.
(3) All open regulated drains shall have an on-site inspection priorto construction plans having been developed. On-site inspection shall be with the HCSO plan reviewer, inspector and developer and/or his or her engineer.
(E) Off-site improvements. If an adequate outlet is not located on-site, then off-site drainage improvements may be required. Those improvements may include but are not limited to: extending storm sewers, clearing, dredging and/or removal of obstructions to open drains or natural watercourses, and the removal or replacement of undersized culvert pipes as required by the County Surveyor. Where the outfall from the storm water drainage system of any developer flows through real estate owned by others priorto reaching a regulated drain or natural watercourse, no approval shall be granted for such stormwater drainage system until all impacted owners either consent in writing to such use of their real estate, or are notified of such proposal and their rights to appeal any approval of the design. Proof of this notification must be submitted to the Hamilton County Surveyor.
(F) Floodplain management. The intent of floodplain management is to protect against loss of property, protect human life, and maintain natural areas that help mitigate flooding. Therefore, infilling of land in the floodplain of regulated drains is prohibited. Floodplain boundaries are to be determined by using the floodway-flood boundary maps of the Federal Insurance Administration/Federal Emergency Management Agency. FLOODPLAIN shall include floodway and floodway fringe areas.
(1) If a Federal Emergency Management Agency floodway-flood boundary map does not establish a 100-year water surface elevation, the 100-yearwater surface elevation shall be established:
(a) By a site specific recommendation from the Indiana Department of Natural Resources; or
(b) Through a site specific engineering analysis performed by a registered professional engineer licensed in the State of Indiana and approved by the Indiana Department of Natural Resources.
(2) Exceptions to this section are as follows:
(a) Agricultural uses, such as crop production, pastures, orchards, tree farms, plant nurseries, vineyards, and general farming.
(b) Forestry, wildlife areas and nature preserves.
(c) Parks and recreational uses, except golf courses and driving ranges.
(d) Public: streets, bridges, and roadways.
(G) General requirements.
(1) All lots will be given access to a subsurface drain, open ditch or other adequate drain as determined by the surveyor.
(2) The allowable discharge rate is the staged detention for the two-, ten- and 100-year, and 24-hour storm events. For small storms (up to the predeveloped ten-year rate) the allowable discharge rate is the cubic feet per second for a predeveloped two-year storm. For storms with intensities between the predeveloped ten-year rate and the 100-year developed rate, the allowable discharge is the cubic feet per second for the predeveloped ten-year storm. The difference is to be detained. In some watersheds the allowable discharge rate shall be based upon the most restrictive downstream structure or channel capacity where the standard allowable release rate has been determined to cause flooding. Detention calculations shall be based on the SCS unit hydrograph or other approved method.
(3) Dry detention basins for residential subdivisions shall be located within areas designed as common areas. Dry detention areas shall not be located either partially or completely within residential lots. The common areas for detention basins shall also be noted as drainage easements. Dry detention basins shall be designed so as to allow for subsurface drainage (SSD) throughout, SSD shall be on 25-foot (on center) parallel runs, minimum of 0.5% gradient with two-foot minimum cover, and have a free positive outlet downstream of the outlet for the basin.
(4) For drainage facilities which will become regulated drains, the following requirements shall be followed:
(a) Storm sewers shall be reinforced concrete pipe with a minimum diameter of 12 inches. Storm sewers shall have a minimum of two feet in cover.
(b) Subsurface drains (SSD) shall be a minimum diameter of six inches and shall be Schedule 35 PVC or Double Wall perforated or non-perforated plastic pipe.
(c) Rear yard and side yard drainage easements for regulated drains shall not be less than 30 feet in width, 15 feet each one-half for storm sewers. Minimum drainage easements for open drains shall be 25 feet from the top of bank. The top of bank shall be determined by the County Surveyor.
(5) All structures shall have minimum finished floor elevations located at least two feet above the 100-year water surface elevations of any watercourse, pond or lake. All development plans and construction plans shall have minimum finished floor elevation denoted on each lot or building.
(Ord. 2000-1-2, passed 1-11-00; Am. Ord. 2013-3-1, passed 3-28-13)