Determine the composite Curve Number for your proposed CSD..
Please use the Conservation Subdivision Design mini project Preview the document View in a new window document for working through this design assignment. Figure 7F-1 is an isometric view of the site before development, while Figure 7F-2 is a plan view of conventional subdivision plot design that you should use for your base case. Using Figure 7F-2 and knowing that the area’s native soil Hydrologic Soil Group is Type B in this location, please answer the following questions. Cedar City Soil Information.pdf Preview the document View in a new window
1. Quantify (in acres) the total development area, the residential development area, the impervious road area, and the primary conservation area identified in the base case.
2. Using the NRCS Curve Number Table Preview the document View in a new window , identify the representative Curve Number for each of the land uses listed in Question 1, assuming the primary conservation area identified in the base case is considered Good cover forest land by the NRCS.
3. Determine the composite Curve Number for the base case, conventional subdivision development plan defined in Figure 7F-2.
4. Knowing that this subdivision is Southeast of Cedar City, determine the expected total rainfall from the design rain storm (24-hr, 25 year return period) that you can access here (Links to an external site.)Links to an external site. (http://dipper.nws.noaa.gov/hdsc/pfds/sa/ut_pfds.html (Links to an external site.)Links to an external site.) .
5. Using this rainfall value and the baseline composite Curve Number, calculate the expected runoff depth (inches) and total runoff volume (acre-ft) expected to be generated from this design rain storm from the conventional subdivision development plan.
6. Using Figure 7F-5, the site plan view identifying additional conservation areas that are deemed important to preserve at the site, show on Figure 7F-4 potential Development Areas that remain at the site, place house sites within these potential Development Areas, and locate roads and trails connecting these house sites to each other within the development and to surrounding roadways outside the development.
7. Use your proposed Conservation Development Plan to quantify residential development areas, impervious road area, and the expanded conservation areas identified in your proposed CSD.
8. Determine the composite Curve Number for your proposed CSD.
9. Using the same design storm as above, determine the expected runoff depth (inches) and total runoff volume (acre-ft) expected to be generated from your proposed CSD.
10. Determine the change (± % change) in runoff volume expected from your proposed CSD compared to the base case, and describe additional benefits your CSD design provided over the conventional subdivision design in terms of Ecosystem Services, and development impact mitigation.
Determine the composite Curve Number for your proposed CSD.
