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a "typical" cross section for input into the SEDCAD model. The sideslopes and bottom width were entered into SEDCAD (see Attachment 7-6-3) and the resulting design was generated. The design depth (generally less than one foot) was compared to ~+j~ field notes and the actual ditch depth was more than adequate. These typical ditch sizes have been included on pages 7-6-3-8 and 7-6-3-9. 19. PWCC assumes that DM&G is referring to Appendix 12-2 and page 12-2-1 but culvert 12A does not have an actual design run on page 12-2-7. The runoff for culvert 12A was not designed by SEDCAD. It was designed using the methods as described in Culverts on page 12-30 (i.e., SCS, Steel Handbook, etc.) 20. Aerial photography, SCS soils maps, and Exhibit 13-6 were used to verify the soils and vegetation types in the prelaw area. The dominant soil types were X8F, 34E & F, and 103 which are all in the B hydrologic group. Approximately 20 percent of the area was in the 2VD soil type, which is the C hydrologic group. Please refer to Attachment 7-6-7 for CN verification; see attached work map for vegetation information. The following shows the results of that study: 894 AC. WATERSHED Vegetation TvDe Area(acl CN Cover($) Hvd. Soil GrouA Dist. Land 39.1 94 N/A B Reclaimed 63.0 70 45.5 B ti, Sagebrush 76.6 51 67.3 B ~•`~Mountain Brush 516.6 48 82.3 B ~v l~,Sandstone 7.7 93 0 D ~yJ~ ~ ;' Meadow 7 .5 69 83 . 9 B ~ Aspen ~` 100.3 30 89.9 B Ponds / ~' 0.4 100 0 N/A Steep Mtn. Brush ~ ~' 99.6 67 39. 3 B ..~ Weighted CN = 52.2 or say 55 to account for the 20 percent soil type C. SEDCAD will not determine a ditch size based on the above curve number due to the fact that the low flow (approximately 0.3 cfs) is insufficient for SEDCAD to design a ditch. Therefore, the original data and curve number (60) have not been revised. 39.5 AC. WATERSHED Vegetation Tvoe Area(acl CN Cover($) Hvd. Soil Grouo Dist. Land 4.8 94 N/A B Reclaimed 43.4 70 45.5 B Ponds 0.5 100 0 N/A 4