ENGINEERING TECHNOLOGY

EGTE 321

Design Project: Storm-Water Management System Design

Part I: Present and Developed Hydrology with Estimated Storage Volumes

100 PTS

Your company has been awarded a contract for the site engineering required to develop a property in New Castle County, DE for a subdivision. Your design team has been given the assignment of developing a storm-water management plan, to be submitted in a series of reports and a final oral presentation. Three AutoCAD files zipped into a single file, Bowen_Acres_CAD.zip, are available on the WebCT course web site and contain all the relevant site information for existing and developed conditions.

For the Part I report, you will submit documentation concerning the present and developed condition hydrology of the parcel for 2-, 10-, and 100-yr return periods. Specifically, your design team’s deliverables for Part I of this project should adhere to the following conditions:

A written storm-water management report must be submitted by the due date specified on the linking web page. Please enclose the report in a three-ring binder. Single-sided printing is preferable, but not required. The written report should, at a minimum, include the following components:

  • Narrative
  • Introduction
  • Soils descriptions
  • Summary of existing conditions, peak flows
  • Summary of proposed conditions, preliminary storm-drain design, peak flows
  • NCC storm-water management requirements
  • Appendices (Typically, the format for each appendix should be a brief narrative with accompanying computer output.)
  • Present (existing) condition hydrology with all calculations
  • Preliminary Storm-Drain Design – Include appropriate StormCAD output.
  • Developed condition unrouted hydrology with all calculations and relevant computer output.
  • Your design must follow the pertinent government regulations detailed in the following documents:
  • Chapter 12 – Drainage – of the New Castle County Code, web site:
  • DNREC Sediment and Storm-Water Regulations, web site:
  • Other Specific Information and Requirements:
  • Note that 24-hr precipitation values for Delaware have been updated in light of the recent extreme rainfall events. The two, ten, and one hundred year return period depth values for New Castle County, DE are now: 3.2, 4.1, and 8.1 inches, respectively (
  • Include a drawing in your report that shows time of concentration pathways, modes of flow, and lengths of flow for present and developed conditions.
  • Roof runoff can be channeled to the storm-drain system near any building location where a collection point is situated. It can also be discharged onto pervious areas.
  • In calculating peak runoff rates for design of the storm-drain system, do not use a time of concentration shorter than 5 minutes for the rational method. Enter the intensity-duration-frequency rainfall data from your Delaware DOT handout into StormCAD.
  • Consult the New Castle Drainage code to determine design requirements for storm drains, storm drain inlets in sump locations, and surface drainage channels (swales).
  • You are required to design the storm drain systemsconnecting the inlets, locations of which are shown in the AutoCAD file. Use HEC-22 (see link under course information) to obtain realistic estimates of minor losses at the storm drain nodes that are typically comprised of manholes and catch basins. The Delaware DOT drainage manual, Chapter 6 of the Road Design Manual(on reserve in the Ag. Library or on the web at also a good source of information regarding storm-drain design. One of the three AutoCAD files contains an example of the storm-drain profile and relevant information that should be included in your report.
  • For developed land uses that include impervious areas, assume pervious areas are open space in good hydrologic condition.
  • Some references on reserve in the College of Agriculture and Natural Resources library:
  • New CastleCountySoil Survey
  • Delaware DOT drainage manual
  • Delaware Erosion and Sediment Control Handbook (You can download the latest pdf version from the WebCT site.)
  • Examples of complete storm-water management reports
  • At the conclusion of this part of the project and each subsequent part, each individual in your group will be required to fill out and submit a confidential assessment form like the one appearing on the next page. The assessments will influence each person’s individual grade.
  • Each part of the report will be evaluated by the standards similar to those outlined in the evaluation rubric for the final report attached to the end of this assignment.

Assessment Form: Relative Contributions of Team Members[1]

Participant: ______Team: ______Date: ______

Storm-Water Management
Group Design Project Part I
Team members
(include yourself) / Individual contributions to this team project: (Allocate 100 points to your team members, including yourself. Base the allocation on your opinion of each individual’s contribution. The sum of all points allocated must equal 100.) /

Comments

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SWM Design Project

Part I: Hydrology

Grading Rubric

Task / Highly Competent
(2) / Competent
(1) / Needs Improvement
(0)
Narrative, appendices, and supporting materials as described in assignment. / Report is complete with clear, concise discussion of relevant regulations, assumptions, and design considerations. Analysis is complete and done correctly. All relevant supporting documentation is included in appendices. / Report is complete; design work and analysis are supported with adequate documentation and some commentary regarding major regulatory aspects, assumptions, and design considerations. There may be one or two minor omissions or errors in analysis. / Report incomplete and analysis is inadequate or faulty with little or no discussion of major regulatory aspects, assumptions, and design considerations. There may be significant design errors or the design may be inadequately documented.

Specific Components:

  • Narrative
  • Introduction
  • Soils and land-use descriptions
  • Summary of existing conditions, peak flows at a clearly defined point of interest
  • Summary of proposed conditions, preliminary storm-drain design, peak flows
  • NCC storm-water management requirements for quantity and quality
  • Appendices (Typically, the format for each appendix should be a brief narrative with accompanying computer output.)
  • Present (existing) condition hydrology with all calculations including time of concentration pathways
  • Preliminary Storm-Drain Design – Include appropriate StormCAD output and profiles.
  • Developed condition unrouted hydrology with all calculations and relevant computer output.

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[1]After Fletcher, Lugowski, and Stern. 2002. Fluid Power Facilitator Guide. SinclairCommunity College.