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<br />I <br /> <br />I <br /> <br />Additional construction requirements included riprap downstream of chan- <br />nel crossings, a headwall to reduce entrance losses at the Union Pacific <br />Railroad crossing, bank protection along Fossil Creek near Portner Reservoir, <br />stabilization of the southwest wingwall at the C&S Railroad crossing on Fossil <br />Creek, and protection of the downstream embankment at Fossil Creek Drive and <br />Fossil Creek. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />Table 29 presents a summary of the design data for Alternative 3. The <br /> <br /> <br />table includes design storage volumes, surface area, outlet capacity and <br /> <br />outlet dimensions. <br /> <br />I <br /> <br />I <br /> <br />8.2.4 Alternative 4 <br /> <br />Alternative 4 (Figure 32) considers raising road embankments in order to <br /> <br /> <br />maintain three feet of freeboard at channel crossings and preventing develop- <br /> <br />ment within the laO-year flood plain during the laO-year recurrence interval <br /> <br /> <br />flood for developed conditions. Alternative 4 also includes channelization <br /> <br /> <br />from the Union Pacific Railroad to Fossil Creek Reservoir due to the limited <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />storage behind county Road 11. <br /> <br /> <br />Embankments were raised along Fossil Creek at COunty Road 11, Trilby Road <br /> <br /> <br />(County Road 34), Lemay Avenue (County Road 13) and Shields Street. To evalu- <br /> <br />I <br /> <br />ate this alternative, embankments were raised along Stanton Creek at County <br /> <br />Road 32 and Lemay Avenue (County Road 13) and along Lang Gulch at Trilby Road <br /> <br />(County Road 34) and Shields Street. The design data for these improvements <br /> <br /> <br />are presented in Table 30. <br /> <br /> <br />Other necessary improvements include riprap downstream of channel cross- <br /> <br /> <br />ings, a headwall to reduce entrance losseF at the Union Pacific Railroad <br /> <br /> <br />crossing, bank protection along Fossil Creek near portner Reservoir, stabili- <br /> <br />zation of the southwest wingwall at the C&S Railroad crossing on Fossil Creek <br /> <br /> <br />and protection of the downstream embankment at Fossil Creek Drive and Fossil <br /> <br /> <br />Creek. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />60 <br /> <br />Table 29. Alternative 3, Design Data for Sizing Detention <br />Ponds and Outlets. <br /> <br />Location <br /> <br />Storage <br />Volume <br />(ac-ft) <br /> <br />Oulet <br />Capacity <br />(cfs) <br /> <br />Proposed <br />Outlet <br />Dimension <br /> <br />Surface <br />Area <br />(acres) <br /> <br />Fossil Creek <br /> <br />Reach 1, County Road 11 <br /> <br />30 <br /> <br />Reach 2, Union Pacific <br />Railroad and Trilby <br />Road (County Road 34) <br /> <br />600 <br /> <br />Reach 2, County Road 13 <br />(Lemay Ave) <br /> <br />19.5 <br /> <br />Reach 5, Shields Street <br /> <br />9 <br /> <br />Stanton Creek <br /> <br />Reach 6, County Road 32 <br /> <br />13.6 <br /> <br />Reach 6, County Road 13 <br />(Lemay Ave) <br /> <br />26 <br /> <br />Lang Gulch <br /> <br />Reach 7, County Road 34 <br />(Trilby Road) <br /> <br />3 <br /> <br />Reach 7, Shields Street <br /> <br />44 <br /> <br />570 <br /> <br />1-6'xl0' box <br /> <br />11 <br /> <br />1,300 2-6'xl0' box 10 <br />1,380 Existing 25 <br />1,550 2-6'x12' box 60 <br />3,200 10'x32' span 4 <br />500 1-6'xl0' box 2 <br /> <br />880 <br /> <br />2-4'x12' box <br /> <br />3 <br /> <br />780 <br /> <br />2-4'xl0' box <br /> <br />5 <br /> <br />400 <br /> <br />1-4.xl0. box <br /> <br />1 <br />