Need to use HEC-RAS software and take screen shots.

Engineering problem statement: A builder would like to develop a large tract of land near the upstream portion of Big Creek to create a residential area and shopping centers. A hydrologic study performed for this area concludes that the development would add 2,200 cfs of additional flow to the 100 -year storm, which is 4,825 cfs at the mouth of the reach. Th is in turn would raise the water surface elevation at the cross section farthest upstream by 1.71 ft above the existing elevation. Regulations require that a development cannot raise the water surface elevation downstream of the development by more than 0. 01 ft. The developer has two options. The first is to build a detention pond in order to alleviate the impact of increased flow. However, this would tie up some of his land, which is very valuable to the developer. Therefore, the builder is interested in t he feasibility of channelizing the portion of Big Creek downstream of the point of impact. Project Tasks A. Answer questions 1 to 8 about the existing geometry and flow data. Provide screenshots and a description of the HEC -RAS menus and submenus leading t o the given screen to support each of your answers. 1. What is the length of the entire reach (determined in the main channel) in feet and in miles? Describe how you determined your answer. 2. Are there any hydraulic structures present in the reach? If yes , what type and how many of each? 3. How many general cross sections (i.e. where hydraulic structures are not present) are in the reach? 4. Are there any cross sections that have been generated using the cross section interpolation tool in HEC -RAS? If yes, specify which. Explain your answer. 5. What are the values for the main channel bank stations for river station 86174? 6. Provide a screenshot of the X -Y-Z perspective plot of the reach. 7. Provide a screenshot that shows the discharge data for the existi ng 100 -year flow. What is the range of flow values in the reach? 8. What type of boundary condition has been specified for the existing 100 -year flow? Provide the value specified if applicable. B. Perform a steady flow analysis on the existing 100 -year flo w data (use a subcritical flow regime) and evaluate the impact of the modifications described in questions 1 to 4. Provide a screenshot of the entire HEC -RAS window, i.e. showing the menu points and the window name, as part of each answer. In addition, include a description of the HEC -RAS menus and submenus leading to the given screen. 1. Show the following for the existing 100 -year flow s imulation: a. The water surface profile. What is the water surface elevation at river station 109047 (i.e. the most upstream cross section)? b. The X -Y-Z perspective plot c. The cross section plot for river station 109047 (no hydraulic structure) d. All br idge cross section plots. Describe the impact of the two bridges on flow (i.e. the type of flow that you can observe at the two bridges). 2. Rerun the model with the increased flow rate due to the planned development (i.e. add 2,200 cfs to your existing fl ow data, hint: create a new flow file with the name “100 yr develop”) and compare to the existing conditions. Show the new water surface profile plot. How did the water surface profile change compared to the existing condition? What is the water surface el evation at river station 109047 (i.e. the most upstream cross section) under the increased flow conditions? How did flow conditions change at the two bridges? 3. Evaluate the impact of removing the upstream bridge at Section 106365 on the water surface pro file that you determined for the increased flow conditions (hint: create a new geometry file with the name “Geometry no U bridge”). Show the water surface profile plot without the upstream bridge. How did the water surface profile change? Explain the reaso n why. What is the water surface elevation at river station 109047 (i.e. the most upstream cross section) under these conditions? How did flow conditions change at the downstream bridge? 4. Investigate the impact of changing the Manning’s n values for the channel from 0.04 to 0.06 and for the right and left overbank areas from 0.08 to 0.1. Perform this evaluation for the existing geometry and the existing 100 -year flow conditions (hint: create a new geometry file with the name “Geometry increased n value”). Show the water surface profile plot. Did the water surface profile change compared to what you have observed for the existing conditions? Explain the reason why or why not. What is the water surface elevation at river station 109047 (i.e. the most upstream cross section) under these conditions? How did flow conditions change at the two bridges?