• The purpose of this lab is to demonstrate an understanding of the principles of inventory routing and their applicability to the design of stormwater control structures.

• Hydrology, Water Quantity and Quality Control textbook
• SMADA Software

A watershed is to undergo the following changes in watershed characteristics due to development:

The precondition watershed is primarily pasture in fair condition, the soils are well drained, and roughly a 50/50 mix over the area of type A and B soils. The pervious areas in the postcondition retain these soil characteristics.

You will need to generate hydrographs for this watershed for both the pre- and postdevelopment conditions. Generate a hydrograph using the SCS Type II distribution for both the 5-year and 25-year return periods (24-hour storm). The development is in Orlando, Florida.

Regulations state that the peak flow in the postcondition must be less than or equal to the precondition peak flow. To meet this requirement, a detention pond must be designed. The site which is chosen for this pond is just outside of the boundaries of the watershed. The ground is fairly flat at this location at an elevation of 105 feet. The groundwater table is at 100 feet at this location (no temporary storage will be provided below this level).

Determine a stage-storage-discharge relationship for this pond so that it meets the design requirements. Provide drawings (plan view and at least two cross-sections) of your pond including the important measurements for construction. You must select and place an outlet control device (weir) on your pond. Route both the 5-year and 25-year hydrographs through your pond.

Your report should include the following:

• Table containing information about the watershed and rainfall characteristics (program input) for both the pre- and postconditions with both correctly labeled (Results).
• Plot of pre- and postcondition hydrographs for both storms, with peak flow (in cfs) noted on the plot (4 hydrographs) (Results).
• Printout of pond stage-storage-discharge relationship (Results).
• Table including information about weir selection and placement and pond dimensions (Results).
• X-Section (from side) plot of pond (with weir placement, GW Elevation, ...) (Appendix).
• Construction Drawings (Appendix).
• Plot of pond inflow and outflow for both storms. Be sure to specify the peak flows on the plot for the pond outflow hydrograph (2 plots) (Results).
• Cost Estimation for the pond (Appendix).