(A) Application and approval process.
(1) Conceptual review. A cursory review of stormwater management and water quality improvements, including verification of an adequate outlet will be completed by the Development Services Department during the plan review period for zoning map amendment.
(2) Preliminary review.
(a) Stormwater management features shall be included in the Primary Plat submittal. Drainage easements shall be included in accordance with § 151.21(J).
(b) The primary plat submittal shall be reviewed by the Stormwater Department to ensure that conceptual stormwater management systems have been included and requirements of this chapter are acknowledged by the applicant.
(3) Final review.
(a) Stormwater management features shall be included in the Development Plan and Final Plat submittal. The legal description of the lot or site shall include the appropriate drainage easements in accordance with § 151.21(J).
(b) The Development Services Department or their authorized representative shall perform a review of all stormwater, erosion control and pollution prevention features included in the Development Plan for compliance with the requirements and intent of this chapter. Final review shall include engineering/technical plan review.
(c) Stormwater Management Plan approval shall be obtained prior to the initiation of any construction activities. Non-compliance with the terms and conditions of the approved Stormwater Management Plan will be subject to enforcement as described in this chapter. The applicant shall inform all contractors, sub-contractors, construction management firms, and other entities having oversight of construction activities on the site or individual building lots of the terms and conditions of the Stormwater Management Plan approval and schedule for proposed implementation.
(B) Minimum requirements of all projects.
(1) All projects shall comply with the requirements of this section. The Development Services Department may require projects with one (1)
(2) Application for approval shall include the following items at a minimum:
(a) Completed application;
(b) Stormwater application fee (according to an established fee schedule). Inspection fees shall be assessed following application. Fees are to be paid prior to the pre-construction meeting with Town personnel;
(c) Statement of financial responsibility form, signed and completed;
(d) Affidavit and consent of property owner form, signed and completed;
(e) Design plans. Design plans certified by a professional engineer or land surveyor licensed in the State of Indiana. Each sheet shall be drawn to scale and shall include a scale bar and north arrow. Plans shall include the following sheets and elements at a minimum in order to show the nature, location, dimensions, and elevations of the area and improvements in question.
1. Title sheet:
a. Location plan;
b. Vicinity map;
c. Legal description of property;
d. Parcel number or numbers of the site;
2. Overall existing condition site plan:
a. Location, elevation, and datum of benchmark placed within the area of the site. If no benchmark is available, the elevation of the nearest road intersection as shown on the U.S. Geological Survey Map shall be indicated;
b. Site and the surrounding area one hundred (100) feet in every direction around the site;
c. Location, size, and invert elevation of any drainage structures within one hundred (100) feet of the site;
d. Existing site grading with contour intervals of one (1) foot;
e. General description and nature of the site;
f. Soil survey map with the site delineated upon it;
3. Existing condition plan sheets (maximum scale of one (1) inch equals fifty (50) feet):
a. Contour lines with maximum one (1) foot contour interval;
b. One hundred-year (100-yr.) (1% chance/year) floodplain elevation and boundary;
c. Existing legal drains and other waterways, detention/retention facilities, roadside ditches and culverts, storm sewer systems, and all other drainage features as applicable;
d. Areas potentially impacted by flooding of surface waters including;
4. Designated floodways or floodplains;
5. Land within seventy-five (75) feet of each bank of any legal drain;
6. Land within fifty (50) feet of each bank of a natural drainageway;
7. Areas above restricted outlets;
8. Wetlands:
a. Street names, widths, and rights-of-way;
b. Existing easements;
9. Proposed condition plan sheets (maximum scale of one (1) inch equals fifty (50) feet):
a. Contour lines with maximum one (1) foot contour interval;
b. One hundred-year (100-yr.) (1% chance/year) floodplain elevation and boundary;
c. Pond water surface elevations including 100-yr. (1% chance/year) and normal pool elevations;
d. Proposed grading and areas of cut or fill;
e. Elevation of the first floor for all proposed and existing structures;
f. Elevation of lowest floor, including basement, for all proposed and existing structures in accordance with § 151.21(K);
g. Proposed areas for storage of materials and construction staging;
h. Proposed modifications to existing drainage features;
i. Proposed discharge location for site;
j. Location and size/ dimensions of all existing and proposed detention/ retention facilities, roadside ditches and culverts, subsurface drains, legal drains, and all other drainage features, whether permanent or temporary, including those facilities which are crossing or adjacent to the site;
k. Location, size/ dimensions, and profile of all existing and proposed storm sewer systems, whether permanent or temporary, including those facilities which are crossing or adjacent to the site;
l. Drainage plan including flow arrows for both surface and subsurface water. The drainage plan shall indicate the natural flowage of water to be managed coming into or leaving the site;
m. Flood routing plan including path and ponding locations and flow arrows and standards included in § 151.21(I);
n. Street names, widths, rights-of-way, and cross sections, including elevation of street centerline;
o. Existing and proposed easements;
10. Design details, including applicable standard details from the Town of Brownsburg Construction Standards;
11. Stormwater Pollution Prevention Plan (SWPPP), details, and notes in accordance with§ 151.22;
(f) Drainage report. Engineering design computations and drainage report prepared by a registered Professional Engineer or Land Surveyor licensed in the State of Indiana which include the following applicable items at a minimum:
1. Written description of the project, including:
a. Discussion of the steps taken in the design of the stormwater management system;
b. Description of significant drainage problems;
c. Soil types, conditions and limitations;
d. Analysis procedure to evaluate problems and propose a solution;
e. Hydrologic and hydraulic analysis methodologies and calculations;
f. Exhibits showing existing and proposed drainage patterns, drainage areas, flow paths, land uses, and the like;
g. Assumptions or special; conditions associated with the methods used;
h. Proposed design of stormwater management system;
i. Results of analysis demonstrating that proposed system addresses existing drainage problems, accounts for off-site drainage (if applicable), and does not create new drainage problems upstream or downstream of the site;
j. Proposal for protecting proposed improvements from loss or damage due to ponding or runoff of surface water;
k. Conclusion summarizing the design and explaining how the design satisfies the requirements and intent of this chapter.
2. Engineering design computations shall be provided for land drainage practices, erosion control measures, pollution prevention practices, and flood prevention practices, including, but not limited to:
a. Runoff coefficients or curve numbers, as appropriate;
b. Times-of-concentration;
c. Peak runoff rates;
d. Detention storage volumes;
e. Peak discharge rates;
f. Outfall structure and emergency spillway calculations;
g. Storm sewer, inlet, open channel, culvert, subsurface drain, and other stormwater conveyance design calculations;
h. Low-impact development features design calculations and supporting information;
i. Input and output files for computer models and exhibits detailing the setup and relationships within the computer model;
(h) Performance bonds. As condition of Stormwater Management Plan approval, the applicant shall provide performance assurances in accordance with § 151.26.
(3) Where the minimum standards of this chapter cannot be met, additional engineering design calculations and narrative shall be provided to the Development Services Department for consideration.
(Ord. 2017-28, passed 10-12-17)