Department of Urban and Regional Planning   
University of Illinois at Urbana-Champaign   

UP 503: Site and Physical Planning

6d. Site Engineering Analysis: Storm- and Wastewater Management

Objectives: To understand the concepts and terminology of stormwater and wastewater management planning, and be able to work out in rough terms the engineering requirements for 1) stormwater conveyance, detention and/or retention, and 2) a sanitary sewer system on your site

This assignment covers the site engineering approaches to planning for stormwater and wastewater management. While planners are not typically responsible for the design of these systems, planners are often tasked with reviewing the preliminary plat of a developer’s proposal to ensure the site layout will function as designed. Engineers in a city's public works department will review construction drawings associated with a final plat and check that the proposed site engineering meets standards, but there is typically no such intervention at the stage when a planner is reviewing a preliminary plat. Instead, the planner will have to roughly assess that the plat can be implemented.

With this in mind, your task is to work out in rough terms, the site engineering (storm- and wastewater systems) required to implement your development proposal. Traditional stormwater management design and layout has been focused on collecting stormwater in a piped system and moving it off-site as quickly as possible, often to the detriment of the receiving system or body of water. As a result, you should design an overland stormwater management system that puts the existing site contours to work, using existing drainage paths to transport stormwater through a network of BMP elements (swales, buffers, rain gardens…) that minimize, clean and slow down stormwater flow. Use the course readings and lecture slides to help develop your understanding of the basic concepts and principles that lead to good site engineering practices. Your assignment should include the following:

  • Design an overland stormwater system based on site suitability characteristics and BMPs
    • Identify preliminary land use areas (e.g. residential, commercial, open space…) on your site
    • Identify and discuss the type and location of BMPs (swales, buffers, rain gardens…)
  • Assess the retention and/or detention needs of your site
    • Adjust according to the expected percent reductions from the Hydro.xls model
    • Identify pond locations on site and discuss their design (e.g. area and depth)
  • Annotate the locations of potential connections to existing sewer lines – remember these lines would eventually be located under the development’s new roads and streets
    • Assume an invert elevation of 6 to14 feet below ground and verify that the various land use areas could be adequately serviced by a gravity flow system (a minimum slope of 0.25)

Synthesize your analysis in a brief 'memo' format that combines a map visualizing your design with text summarizing the key concepts that underlie your stormwater and wastewater management plan for the site. We will discuss your work in the next lab session. This document named by 6d_[Last Name].pdf is to be uploaded to the Assignment Dropbox folder before start of class on Thurs, Nov 14.

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