HYDRAULIC ANALYSES

FOR

COLE GRADE ROAD CROSSINGS

October 3, 2022

Wayne W. Chang, MS, PE 46548, Exp. 6/30/2023

Chang Civil Engineering ◦ Hydrology ◦ Hydraulics ◦ Sedimentation

P.O. Box 9496 Rancho Santa Fe, CA 92067

(858) 692-0760

TABLE OF CONTENTS

Introduction

Hydraulic Analyses

Scour Analysis and Drift

Conclusion

Existing Culvert Data and Soil Work Sheet

APPENDIX

A. 100-Year Hydraulic Analyses

MAP POCKET

Keys Creek Junction Hydrology HEC-RAS Work Map Cole Grade Road and Culvert Plans CD Containing HEC-RAS files

INTRODUCTION

Cole Grade Road is an existing County of San Diego roadway (community collector) consisting of two lanes (one lane in each direction) within the Valley Center community. Cole Grade Road extends primarily in a north-south direction over several miles from Valley Center Road at the south to State Route 76 at the north (see Vicinity Map).

Cole Grade Road is scheduled to be improved along a 2.3 mile stretch from Horse Creek Trail to Oak Meadow Road. The improvements will convert Cole Grade Road from a 26-foot-wide two-lane road to a modified version of the County 2.1 D Community Collector roadway. Nasland Engineering (Nasland) is preparing final engineering plans for the road improvements. A natural unnamed watercourse crosses Cole Grade Road just south of Cool Valley Ranch Road. The crossing contains double 8-foot wide by 10-foot-high box culverts. A natural tributary to the unnamed watercourse also crosses the road, but just north of Cool Valley Ranch Road and with a single 6-foot by 6-foot box culvert.

Nasland previously prepared the May 1, 2014, Final Hydrology Report for Cole Grade Road Improvements, Keys Creek Tributaries. Nasland determined the 100-year flow rate at the double and single box culverts to be 3,373 and 353 cfs, respectively. The combined 100-year flow rate below the confluence was 3,928 cfs (see the Keys Creek Junction Hydrology exhibit in the map pocket). Chang Consultants’ January 9, 2015, Preliminary Hydraulic Analyses for Cole Grade Road Crossings, determined that the existing culverts cannot adequately convey the 100-year flow rates. The approved existing condition analyses and discussion from the 2015 report are reproduced herein for reference.

Under the proposed design, Nasland’s storm drain improvements have altered the above flow rates at some locations due to different discharge points into the streams. According to Nasland, the combined 100-year flow rate has increased from 3,928 to 4,062 cfs. The 100-year flow rate at the larger Cole Grade Road crossing has increased from 3,373 to 3,488 cfs.

The 2015 report analyzed various replacement alternatives for the two crossings. It has been decided that the double box culverts along the unnamed watercourse shall be replaced with a bridge. In addition, the single box culvert along the tributary watercourse will be replaced with a larger box culvert at the same location. This report contains final hydraulic analyses of the unnamed watercourse and its tributary watercourse.

Nasland Engineering provided the Cole Grade Road bridge and culvert plans, which are included in the map pocket. The exhibits show that the double box culverts will be replaced with a clear span bridge along the Cole Grade Road alignment. The channel bed at the bridge is 34.7-feet wide perpendicular to the flow direction. In addition, the single 6-foot by 6-foot box culvert will be replaced with an 8-foot wide by 6-foot-high box culvert.

Nasland has prepared grading for a lateral channel that confluences into the unnamed watercourse just upstream of Cole Grade Road. The lateral channel is south of the unnamed watercourse. Nasland determined the 100-year flow rate in this channel to be 536 cfs. A hydraulic analysis has also been performed for the proposed southerly lateral channel.

HYDRAULIC ANALYSES

Hydraulic analyses using the US Army Corps of Engineers’ HEC-RAS model (version 6.3) were performed for the proposed condition 100-year hydraulics along the project area. In addition, the County of San Diego requested that the 10- and 50-year flow rates be included. The study reaches have not been previously analyzed by the County of San Diego nor FEMA. The following describes the HEC-RAS input parameters and the results.

The HEC-RAS cross-sections and reach lengths were based on 1-foot contour interval topographic mapping prepared for the project, where available. According to Nasland, the mapping and all plans are on NGVD 29 vertical datum. Consequently, the analyses are on NGVD 29. The HEC-RAS work map in the map pocket shows that the mapping only covers a strip along either side of Cole Grade Road. Additional field survey was performed over a portion of cross-sections 2 through 5 (the field survey points are included on the HEC-RAS Work Map) and used to generate these cross-sections.

The County’s 5-foot contour interval orthotopographic mapping was used to supplement the recent mapping and field survey data, where needed. The HEC-RAS Work Map contains these three mapping sources and identifies the cross-section locations.

The existing box culverts in the existing condition analysis are based on the data sheets included after this report text and field survey information. The new bridge and enlarged box culvert in the proposed condition analyses are based on the Cole Grade Road bridge and culvert plans. Skew factors were applied to the bridge to result in a 34.7-foot-wide channel bed perpendicular to flow.

Additional input parameters are as follows. The roughness coefficients for natural, undisturbed areas were based on County criteria as well as current field conditions observed from aerial photography (Google Earth) and a site visit. A roughness of 0.10 was used for the channel areas, which contains relatively dense and mature trees and brush (see Figures 1 and 2). Discussions with County Flood Control staff revealed that for existing natural channels, the roughness can be based on the long-term vegetative conditions. County staff concurred that a roughness of 0.10 will be conservative for establishing water surface elevations based on the figures and long-term vegetative conditions.

Figure 1. Looking Downstream along Main Channel

Figure 2. Looking Upstream along Main Channel

A roughness of 0.040 to 0.050 was used for the existing overbank areas, which contain lower lying vegetation. Under proposed conditions, portions of the graded channel areas will be lined with gabions, riprap, an articulated concrete block mat, or A-Jacks. The gabions were assigned a roughness of 0.040 to reflect rounded cobbles, the riprap assigned a roughness of 0.047, and articulated concrete block mat assigned a roughness of 0.040 to reflect low lying vegetative growth in the cell openings. The A-Jacks has a roughness coefficient of 0.10. Where two different lining types meet, an average roughness coefficient was used. For instance, the roughness coefficient at the upstream and downstream edges of the A-Jacks was assigned 0.070.

The starting water surface elevation in the unnamed watercourse was established using normal depth with a channel slope of 0.5 percent. The 10-, 50-, and 100-year flow rates were based on Nasland’s hydrology (see the Keys Creek Junction Hydrology exhibit after this report text). Nasland determined the flow rates within the unnamed and tributary watercourses as well as below their confluence. Expansion and contraction will occur near a bridge or culvert. Typical contraction ratios are 1 to 1 (this is also mentioned in Appendix B of the HEC-RAS Hydraulic Reference Manual) and expansion ratios are approximately 1.3 to 1. Encroachments were used to model the contraction and expansion, where needed, and are shown on the HEC-RAS Work Map.

The existing condition HEC-RAS analyses indicate that flow from the unnamed watercourse can spill north over Cool Valley Ranch Road. Similarly flow from the tributary watercourse can spill south over Cool Valley Ranch Road. In order to model the spillover from each stream, lateral weirs upstream of Cole Grade Road were added to the unnamed watercourse and to the tributary watercourse. The lateral weirs were included in the existing and proposed condition analyses. The lateral weir crests were based on the high ground elevations along Cool Valley Ranch Road. Based on prior feedback from Flood Control, a weir coefficient of 2.0 was assumed and the energy grade was used for the weir flow reference. The weir flow was modeled to exit out of the system because of hydrologic timing differences between the two streams.

Water-course

Alternative Location1 10-Year Event 50-Year Event 100-Year Event Flow

Rate, cfs Elev., ft.

Flow

Rate, cfs Elev., ft.

Flow

Rate, cfs Elev., ft.

Primary Existing3 Downstream 1,7452 1,427.45 2,4782 1,429.13 2,6882 1,429.49

Upstream 1,7452 1,435.51 2,4782 1,436.70 2,6882 1,436.97 Prop. Bridge Downstream 2,422 1,428.40 3,149 1,429.67 3,4852 1,430.12 Upstream 2,422 1,428.85 3,149 1,430.17 3,4852 1,430.67

Tributary Existing3 Downstream 1992 1,429.07 2102 1,429.16 2152 1,429.20 Upstream 1992 1,435.60 2102 1,435.80 2152 1,435.89 Prop. RCB3 Downstream 2292 1,427.76 2772 1,428.51 2922 1,428.92 Upstream 2292 1,432.18 2772 1,432.58 2922 1,432.70

1The upstream and downstream locations are based on the cross-sections just upstream and downstream of the bridge (8 and 200 for existing conditions, and 8.1 and 198 for proposed conditions) and culvert (102 for proposed conditions, 103 for existing conditions, and 200 for both conditions).

2These flows are lower than the Nasland hydrology because they reflect flow loss through the lateral weir.

3The existing condition and Proposed RCB results are from prior analyses. Only the proposed bridge (and southerly lateral channel) analysis was updated for this report.

Table 1. Hydraulic Summary Table

The existing and proposed condition 10-, 50-, and 100-year HEC-RAS results are included in Appendix A and summarized in Table 1. The existing condition and proposed RCB analyses and results were prepared previously and included in prior reports. This report updates the proposed condition analyses for the bridge and southerly lateral channel. In some scenarios, flow out of the lateral weir will occur as mentioned in the prior paragraph. The existing condition results indicate that the double box culverts along the primary southerly unnamed watercourse do not have capacity for even the 10-year flow. The flow overtops Cole Grade Road at the culverts and the water surface extends over the road surface.

In addition, under existing conditions the flow leading up to the single box culvert along the tributary watercourse will overtop the channel banks and a portion will be directed towards Cool Valley Ranch Road. The ground surface at the intersection of Cool Valley Ranch Road and Cole Grade Road is close in elevation to the Cole Grade Road centerline. Therefore, the County’s freeboard requirement for culverts (1-foot below roadway centerline or top of curb, whichever is lower) is not met under existing conditions due to the spillover. The existing condition analyses were merely used to verify that the culverts and drainage courses do not meet freeboard requirements. Other considerations such as the impact of the spillover flows is not required by the current studies.

Additional existing condition HEC-RAS analyses were performed to estimate the capacity of the existing culverts. For simplicity, the analysis for the double box culverts assumed only flow in the primary watercourse, and the analysis for the single box culvert assumed only flow in the tributary watercourse as well as the downstream reach of the primary watercourse (the flow in the other reaches was assumed to be 1 cfs). The results show that the capacity of the double box culverts is approximately 1,080 cfs when the water surface immediately upstream of the culvert is about 1 foot below the top of the culvert opening. Similarly, the capacity of the single box culvert is approximately 170 cfs when the water surface upstream of the culvert is 1 foot below the top of the culvert opening and assuming no flow losses to the lateral weir.

The proposed bridge has greater capacity than existing conditions and avoids overtopping of Cole Grade Road. According to County criteria, a bridge soffit must have at least a foot of freeboard over the 100-year water surface elevations. This freeboard also accounts for large floating debris according to the County’s written criteria. The 100-year water surface elevation at the proposed bridge is 1,430.67 feet and the soffit is designed at 1,432.15 feet, so the County freeboard criteria is exceeded. The 100-year flow is contained within the HEC-RAS cross-sections near the bridge and will not overtop Cool Valley Ranch Road.

Further upstream of the proposed bridge between cross-sections 202 to 203, the HEC-RAS results show that 3 cfs of the 100-year flow in the unnamed watercourse will spill north out of the channel towards Cool Valley Ranch Road. This flow will be primarily conveyed west in Cool Valley Ranch Road towards Cole Grade Road. As mentioned above, there are timing differences in the unnamed watercourse and tributary watercourse flows. For these two reasons, the flow in the tributary watercourse is not increased due to the spillover.

The proposed 8-foot by 6-foot box culvert along the tributary watercourse can convey its 100-year flow with at least a foot of freeboard from the low point along Cole Grade Road and Cool Valley Ranch Road. Under proposed conditions, a portion of the 100-year flow (61 cfs) from the tributary watercourse can overtop Cool Valley Ranch Road before reaching the 8-foot by 6-foot box culvert as indicated by the lowering of flows through the lateral weir in the HEC-RAS output. The overtopping flow will be directed south of Cool Valley Ranch Road towards the southerly unnamed watercourse.

Even if the upstream condition is improved so that the 61 cfs reaches the 8-foot by 6-foot box culvert, a foot of freeboard from the Cole Grade Road low point will be provided.

Finally, a HEC-RAS analysis has been performed for proposed channelization of a lateral stream that confluences into the main unnamed watercourse from the south. The channel grading and HEC-RAS cross-sections for the southerly lateral channel are included on the work map in the map pocket. The HEC-RAS was based on Nasland’s grading plan and their 100-year flow rate of 536 cfs. The graded channel will be lined with an articulated concrete mat to prevent erosion. A roughness coefficient of

0.040 was selected to reflect vegetative growth in the mat’s open cells. The roughness coefficients beyond the mat limits were assigned based on the existing vegetative conditions outlined above. The upper end of the channel will be lined with A-Jacks, which has a roughness coefficient of 0.10 or

0.070 when averaged with the adjacent channel areas. Cross-section 199 from the unnamed watercourse analysis was duplicated as the starting cross-section. This cross-section was renumbered to 0.199. The 100-year flow rate and water surface elevation from the unnamed watercourse analysis were assigned to cross-section 0.199. The southerly lateral channel results are contained in Appendix

A and show that the proposed channel has capacity up to the upstream end (cross-section 2.7) where it begins to taper back to the existing stream.

SCOUR ANALYSIS AND DRIFT

Scour associated with the proposed box culvert crossing along the tributary watercourse is discussed first. The project will replace the tributary watercourse’s existing 6-foot by 6-foot box culvert with a wider 8-foot by 6-foot box culvert. The concrete floor of a box culvert serves as a rigid grade control that prevents upstream channel bed scour. The proposed box culvert will have a concrete floor, so will continue to act as an upstream grade control. The invert will be lowered from 1,429.99 feet to 1,429.25 feet, but existing riprap and mature trees upstream of the culvert will generally maintain the upstream channel bed elevations.

A site investigation revealed an existing grouping of large boulders a short distance below the 6-foot by 6-foot box culvert. The boulders act as a drop structure and grade control, which maintain the upstream channel bed elevations preventing scour just downstream of the culvert. The boulders shall remain in order to continue providing scour protection for the proposed culvert. The channel bed below the boulders will behave similar to existing conditions since the boulders will continue to convey flow to the downstream channel.

Scour and drift associated with bridges is discussed next. Bridges crossing natural streams can potentially experience several components of scour including long-term degradation, general scour, and local scour. These are described in the Federal Highway Administration’s April 2012, Hydraulic Engineering Circular No. 18, Evaluating Scour at Bridges (HEC-18). The following summarizes the components.

Long-term channel bed elevation changes may be a natural trend or the result of modification to the stream or watershed. The project site is in a rural area with limited manmade alterations to the watercourse or watershed. Therefore, long term changes will primarily be associated with natural trends upstream and downstream of the proposed bridge as well as local impacts near Cole Grade Road. A streambed may be aggrading, degrading, or in relative equilibrium in the vicinity of a bridge crossing over a natural watercourse. Long-term aggradation and degradation do not include the cutting and filling of the streambed at a bridge that might occur during single runoff events (i.e., they do not include contraction and local scour, which are discussed below).

General scour is the general decrease in the elevation of the channel bed across the bridge opening. It does not include localized scour at the foundations or piers (local scour) or the long-term changes in the stream bed elevation (aggradation or degradation). The most common general scour is contraction scour, which typically occurs when a bridge opening is smaller than the flow area of the upstream channel and/or floodplain. The graded channel approaching the bridge is not significantly wider than the bridge opening, so contraction scour will be minimized. Other general scour conditions can result from erosion related to planform characteristics of the stream, flow around a bend, variable downstream control, or other changes that decrease the bed elevation at the bridge.

These other factors do not exist in the vicinity of the proposed bridge.

Local scour is due to a local flow obstruction by a bridge pier/bent or abutment. The bridge does not propose piers. Furthermore, the vertical abutments will not project into the unnamed watercourse.

Therefore, local scour will not be an impact on the unnamed watercourse.

Based on the above discussion, the scour component at the proposed bridge is primarily associated with long-term aggradation and degradation. The project will prevent scour by installing erosion resistant lining on the graded channel bed and banks within and near the bridge. The channel bed under the bridge will be lined with an open cell articulated concrete mat between the vertical abutments. The articulated concrete mat on the channel bed will extend over 40 feet downstream and 60 feet upstream of the bridge. The articulated concrete mat will also be installed on the upstream channel banks as well as on the bed and banks of the southerly lateral channel. The right (north) bank downstream of the bridge will be lined with riprap. The left (south) bank downstream of the bridge is steep and supports trees, so will be lined with gabions, which can accommodate a steeper slope and minimize impacts. A riprap lined drop structure will be constructed near the downstream end of the channelization.

The articulated concrete mat, gabions, and riprap will prevent erosion at the bridge as well as within the graded channel extending upstream and downstream of the bridge. Nasland Engineering will size these lining materials based on the hydraulic results in this report and coordination with manufacturers. The lining will act as a grade control that prevents scour and stabilizes the upstream channel bed. Riprap will extend below the drop structure to transition flow back to the downstream drainage course.

The County of San Diego’s Hydraulic Design Manual specifies a minimum freeboard of 1 foot over the 100-year water surface elevation. County staff has also requested 2 feet of freeboard over the 50-year water surface elevation, which is consistent with State highway criteria. The bridge results show that the 100-year freeboard requirement is exceeded and the 50-year freeboard is 1.99 feet. Both watercourses are natural with mature vegetation. Therefore, drift is a possibility. Piers are not proposed for the bridge, so debris accumulation on piers is not a concern. In order to account for drift, the 100-year freeboard has been increased to 1.49 feet.

CONCLUSION

Final 10-, 50-, and 100-year hydraulic analyses have been performed for Cole Grade Road bridge and culvert improvements. The analyses are based on Nasland’s hydrologic results and bridge/culvert design information. The results show that the bridge will prevent the 100-year flow from overtopping Cole Grade Road in accordance with the County’s published criteria. The bridge will have greater conveyance than the existing box culverts, which are under capacity. An additional analysis was performed for the unnamed tributary and shows that an enlarged culvert can convey the 100-year flow.

APPENDIX A

100-Year Hydraulic Analyses

HEC-RAS Plan: Exist Cond

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Main Creek Upper Reach 203 10-Year Flow 1763.00 1424.80 1435.77 1435.90 0.003511 2.99 624.18 372.96 0.26

Main Creek Upper Reach 203 50-Year Flow 2993.00 1424.80 1436.94 1437.10 0.003246 3.42 1018.46 765.00 0.26

Main Creek Upper Reach 203 100-Year Flow 3373.00 1424.80 1437.22 1437.37 0.003013 3.42 1141.18 785.66 0.25

Main Creek Upper Reach 202.9 Lat Struct

Main Creek Upper Reach 202 10-Year Flow 1763.00 1424.60 1435.67 1435.74 0.001635 2.40 857.60 708.25 0.19

Main Creek Upper Reach 202 50-Year Flow 2883.07 1424.60 1436.89 1436.96 0.001118 2.37 1351.37 804.03 0.17

Main Creek Upper Reach 202 100-Year Flow 3213.02 1424.60 1437.17 1437.25 0.001062 2.39 1465.35 811.21 0.17

Main Creek Upper Reach 201 10-Year Flow 1758.12 1424.30 1435.59 1435.65 0.001284 2.19 900.57 698.73 0.16

Main Creek Upper Reach 201 50-Year Flow 2695.47 1424.30 1436.83 1436.90 0.000967 2.23 1265.29 721.07 0.15

Main Creek Upper Reach 201 100-Year Flow 2966.44 1424.30 1437.11 1437.19 0.000942 2.28 1347.33 723.93 0.15

Main Creek Upper Reach 200 10-Year Flow 1745.22 1423.60 1435.51 1430.01 1435.60 0.000422 1.27 821.89 391.22 0.07

Main Creek Upper Reach 200 50-Year Flow 2478.37 1423.60 1436.70 1430.46 1436.84 0.000506 1.51 954.50 487.97 0.08

Main Creek Upper Reach 200 100-Year Flow 2688.21 1423.60 1436.97 1430.66 1437.12 0.000535 1.58 983.98 492.43 0.09

Main Creek Upper Reach 8.5 Culvert

Main Creek Upper Reach 8 10-Year Flow 1745.22 1415.10 1427.45 1422.89 1428.03 0.014054 6.11 285.49 44.87 0.40

Main Creek Upper Reach 8 50-Year Flow 2478.37 1415.10 1429.13 1424.33 1429.89 0.015857 7.01 353.62 50.98 0.43

Main Creek Upper Reach 8 100-Year Flow 2688.21 1415.10 1429.49 1424.74 1430.31 0.016500 7.28 369.40 52.29 0.44

Main Creek Upper Reach 7 10-Year Flow 1745.22 1414.30 1425.39 1426.62 0.043756 8.89 196.31 33.56 0.64

Main Creek Upper Reach 7 50-Year Flow 2478.37 1414.30 1426.81 1428.33 0.045752 9.94 252.28 47.16 0.67

Main Creek Upper Reach 7 100-Year Flow 2688.21 1414.30 1427.18 1428.73 0.045044 10.07 270.67 51.57 0.67

Main Creek Lower Reach 6 10-Year Flow 2114.70 1415.00 1425.87 1425.92 0.001145 1.86 1135.54 155.92 0.12

Main Creek Lower Reach 6 50-Year Flow 2873.28 1415.00 1427.45 1427.52 0.001213 2.06 1395.03 171.82 0.13

Main Creek Lower Reach 6 100-Year Flow 3105.14 1415.00 1427.84 1427.91 0.001250 2.12 1461.51 175.69 0.13

Main Creek Lower Reach 5 10-Year Flow 2114.70 1411.31 1425.52 1425.67 0.004060 3.09 684.16 100.67 0.21

Main Creek Lower Reach 5 50-Year Flow 2873.28 1411.31 1427.09 1427.26 0.003825 3.39 854.93 118.88 0.21

Main Creek Lower Reach 5 100-Year Flow 3105.14 1411.31 1427.46 1427.65 0.003809 3.48 904.16 147.54 0.21

Main Creek Lower Reach 4 10-Year Flow 2114.70 1409.80 1424.08 1424.65 0.014231 6.05 349.58 46.55 0.39

Main Creek Lower Reach 4 50-Year Flow 2873.28 1409.80 1425.49 1426.22 0.016155 6.87 418.06 50.31 0.42

Main Creek Lower Reach 4 100-Year Flow 3105.14 1409.80 1425.79 1426.59 0.017110 7.17 433.10 51.00 0.43

Main Creek Lower Reach 3 10-Year Flow 2114.70 1410.74 1420.26 1421.23 0.030959 7.93 266.81 45.26 0.58

Main Creek Lower Reach 3 50-Year Flow 2873.28 1410.74 1421.93 1422.89 0.024829 8.00 369.08 81.79 0.53

Main Creek Lower Reach 3 100-Year Flow 3105.14 1410.74 1422.31 1423.25 0.023309 7.94 400.77 84.40 0.52

EXISTING CONDITIONS WITH EXISTING BOX CULVERTS

HEC-RAS Plan: Exist Cond (Continued)

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Main Creek Lower Reach 2 10-Year Flow 2114.70 1408.79 1419.78 1419.91 0.002753 2.86 739.85 101.99 0.19

Main Creek Lower Reach 2 50-Year Flow 2873.28 1408.79 1421.60 1421.74 0.002373 3.03 964.90 154.37 0.18

Main Creek Lower Reach 2 100-Year Flow 3105.14 1408.79 1421.99 1422.13 0.002327 3.09 1036.35 227.02 0.18

Main Creek Lower Reach 1 10-Year Flow 2114.70 1404.50 1419.06 1411.76 1419.31 0.005003 4.02 525.55 62.25 0.24

Main Creek Lower Reach 1 50-Year Flow 2873.28 1404.50 1420.88 1412.92 1421.18 0.005001 4.43 658.51 104.22 0.25

Main Creek Lower Reach 1 100-Year Flow 3105.14 1404.50 1421.27 1413.24 1421.58 0.005004 4.55 703.17 126.48 0.25

Lateral Creek Reach-1 203 10-Year Flow 245.00 1434.00 1436.49 1436.02 1436.64 0.026236 3.08 79.50 731.40 0.53

Lateral Creek Reach-1 203 50-Year Flow 318.00 1434.00 1436.69 1436.20 1436.86 0.026260 3.35 94.84 745.98 0.55

Lateral Creek Reach-1 203 100-Year Flow 353.00 1434.00 1436.77 1436.28 1436.95 0.026481 3.48 101.48 751.94 0.56

Lateral Creek Reach-1 202.9 Lat Struct

Lateral Creek Reach-1 202 10-Year Flow 236.81 1432.20 1435.82 1435.89 0.006876 2.01 117.65 741.60 0.31

Lateral Creek Reach-1 202 50-Year Flow 289.92 1432.20 1436.01 1436.08 0.006969 2.15 134.90 755.49 0.32

Lateral Creek Reach-1 202 100-Year Flow 316.06 1432.20 1436.10 1436.17 0.006847 2.20 143.62 761.08 0.32

Lateral Creek Reach-1 201 10-Year Flow 222.40 1431.30 1435.76 1435.78 0.000668 1.12 199.83 704.45 0.13

Lateral Creek Reach-1 201 50-Year Flow 255.60 1431.30 1435.95 1435.97 0.000661 1.19 217.08 710.74 0.13

Lateral Creek Reach-1 201 100-Year Flow 271.75 1431.30 1436.04 1436.06 0.000655 1.22 225.40 712.93 0.13

Lateral Creek Reach-1 200 10-Year Flow 199.48 1430.20 1435.60 1432.61 1435.68 0.005343 2.21 90.44 369.05 0.22

Lateral Creek Reach-1 200 50-Year Flow 209.92 1430.20 1435.80 1432.68 1435.87 0.005046 2.18 96.24 375.97 0.21

Lateral Creek Reach-1 200 100-Year Flow 214.94 1430.20 1435.89 1432.71 1435.97 0.004911 2.17 99.07 379.26 0.21

Lateral Creek Reach-1 103.5 Culvert

Lateral Creek Reach-1 103 10-Year Flow 199.48 1426.00 1429.07 1429.07 1430.01 0.151649 7.80 25.57 25.57 1.00

Lateral Creek Reach-1 103 50-Year Flow 209.92 1426.00 1429.16 1429.16 1430.11 0.151345 7.82 26.84 26.32 1.01

Lateral Creek Reach-1 103 100-Year Flow 214.94 1426.00 1429.20 1429.20 1430.15 0.150873 7.83 27.46 26.68 1.00

Lateral Creek Reach-1 102 10-Year Flow 199.48 1420.00 1426.08 1426.17 0.006174 2.37 84.02 25.29 0.23

Lateral Creek Reach-1 102 50-Year Flow 209.92 1420.00 1427.67 1427.71 0.002183 1.63 129.03 31.31 0.14

Lateral Creek Reach-1 102 100-Year Flow 214.94 1420.00 1428.06 1428.10 0.001791 1.52 141.47 32.78 0.13

Lateral Creek Reach-1 101 10-Year Flow 199.48 1418.00 1426.08 1426.09 0.000407 0.74 268.51 66.70 0.07

Lateral Creek Reach-1 101 50-Year Flow 209.92 1418.00 1427.67 1427.68 0.000174 0.54 386.53 81.24 0.04

Lateral Creek Reach-1 101 100-Year Flow 214.94 1418.00 1428.06 1428.07 0.000147 0.51 418.83 85.44 0.04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Exist Cond

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Exist Cond

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Exist Cond

RS = 201

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Exist Cond

RS = 200

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Exist Cond RS = 103.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Exist Cond RS = 103.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

.04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Exist Cond

RS = 103

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Exist Cond

RS = 102

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100 120 140 160 180

Cole Grade Road Bridges Plan: Exist Cond

RS = 101

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Cole Grade Road Bridges Plan: Exist Cond

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Exist Cond

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Exist Cond

RS = 201

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Cole Grade Road Bridges Plan: Exist Cond

RS = 200

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Exist Cond RS = 8.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 20 40 60 80 100 120

Cole Grade Road Bridges Plan: Exist Cond RS = 8.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

0 20 40 60 80 100 120

Cole Grade Road Bridges Plan: Exist Cond

RS = 8

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100 120 140

Cole Grade Road Bridges Plan: Exist Cond

RS = 7

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Ineff

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond

RS = 6

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond

RS = 5

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300 350

Cole Grade Road Bridges Plan: Exist Cond

RS = 4

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond

RS = 3

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

0 100 200 300 400 500

Cole Grade Road Bridges Plan: Exist Cond

RS = 2

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

Bank Sta

.04 .1 .04

100 200 300 400 500 600

Cole Grade Road Bridges Plan: Exist Cond

RS = 1

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year Flow

WS 50-Year Flow

WS 10-Year Flow

Ground

HEC-RAS Plan: EC Capacity Profile: Primary

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Upper Reach 203 Primary 1080.00 1424.80 1433.59 1433.77 0.0070 3.41 327 79.58 0.28

Upper Reach 202 Primary 1080.00 1424.60 1433.12 1433.32 0.0080 3.69 306 118.67 0.37

Upper Reach 201 Primary 1080.00 1424.30 1432.57 1432.79 0.0097 3.85 295 212.62 0.40

Upper Reach 200 Primary 1080.00 1423.60 1432.49 1429.1 1432.59 0.0010 1.50 486 195.75 0.11

Upper Reach 8.5 Culvert

Upper Reach 8 Primary 1080.00 1415.10 1425.17 1421.3 1425.60 0.0131 5.27 205 36.21 0.37

Upper Reach 7 Primary 1080.00 1414.30 1421.86 1421.5 1423.69 0.0980 10.87 99 22.47 0.91

Lower Reach 6 Primary 1080.00 1415.00 1422.66 1422.70 0.0012 1.58 683 125.95 0.12

Lower Reach 5 Primary 1080.00 1411.31 1422.32 1422.43 0.0044 2.66 405 76.88 0.20

Lower Reach 4 Primary 1080.00 1409.80 1421.07 1421.43 0.0122 4.82 224 37.53 0.35

Lower Reach 3 Primary 1080.00 1410.74 1417.00 1417.90 0.0430 7.65 141 32.40 0.65

Lower Reach 2 Primary 1080.00 1408.79 1415.95 1416.07 0.0042 2.75 393 79.26 0.22

Lower Reach 1 Primary 1080.00 1404.50 1415.14 1409.8 1415.33 0.0050 3.46 313 46.49 0.23

CAPACITY ANALYSIS FOR EXISTING DOUBLE 8'x10' RCBs

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 201

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 200

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity RS = 8.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 20 40 60 80 100 120

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity RS = 8.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 8

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100 120 140

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 7

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Ineff

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 6

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 5

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300 350

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 4

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 3

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 2

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

Bank Sta

.04 .1 .04

100 200 300 400 500 600

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 1

Station (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

0 200 400 600 800 1000 1200 1400

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

Main Channel Distance (ft)

E le va tio n (f t)

Legend

WS Primary

Ground

2 3 4 5 6 7 8 8.

Main Creek Lower Reach Main Creek Upper Reach

HEC-RAS Plan: EC Capacity Profile: Tributary

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Main Creek Lower Reach 6 Tributary 170.00 1415.00 1417.15 1417.18 0.0036 1.30 131 74.55 0.17

Main Creek Lower Reach 5 Tributary 170.00 1411.31 1416.69 1416.73 0.0036 1.64 103 33.75 0.17

Main Creek Lower Reach 4 Tributary 170.00 1409.80 1415.85 1415.96 0.0092 2.59 66 23.15 0.27

Main Creek Lower Reach 3 Tributary 170.00 1410.74 1413.96 1414.10 0.0136 2.99 57 23.24 0.34

Main Creek Lower Reach 2 Tributary 170.00 1408.79 1410.67 1410.81 0.0325 3.08 55 44.40 0.49

Main Creek Lower Reach 1 Tributary 170.00 1404.50 1409.06 1406.5 1409.13 0.0050 2.05 83 28.17 0.21

Lateral Creek Reach-1 203 Tributary 170.00 1434.00 1436.25 1435.6 1436.37 0.0255 2.73 62 613.62 0.50

Lateral Creek Reach-1 202 Tributary 170.00 1432.20 1435.33 1435.40 0.0108 2.15 79 601.85 0.35

Lateral Creek Reach-1 201 Tributary 170.00 1431.30 1435.22 1435.24 0.0010 1.13 151 663.29 0.15

Lateral Creek Reach-1 200 Tributary 170.00 1430.20 1435.02 1432.4 1435.10 0.0063 2.28 75 294.19 0.23

Lateral Creek Reach-1 103.5 Culvert

Lateral Creek Reach-1 103 Tributary 170.00 1426.00 1428.77 1428.8 1429.71 0.1522 7.80 22 23.09 1.00

Lateral Creek Reach-1 102 Tributary 170.00 1420.00 1424.07 1422.9 1424.34 0.0310 4.18 41 17.70 0.49

Lateral Creek Reach-1 101 Tributary 170.00 1418.00 1420.34 1420.3 1421.01 0.1422 6.54 26 19.93 1.01

CAPACITY ANALYSIS FOR EXISTING SINGLE 6'x6' RCB

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 6

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 5

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Bank Sta

.04 .1 .04

0 50 100 150 200 250 300 350

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 4

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 3

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Bank Sta

.04 .1 .04

0 100 200 300 400 500

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 2

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Bank Sta

.04 .1 .04

100 200 300 400 500 600

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 1

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 201

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 200

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity RS = 103.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity RS = 103.5 Culv

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 103

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 102

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100 120 140 160 180

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

RS = 101

Station (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

0 200 400 600 800 1000 1200 1400

Cole Grade Road Bridges Plan: Exist Cond - Approx Capacity

Main Channel Distance (ft)

E le va tio n (f t)

Legend

WS Tributary

Ground

2 3 4 5 6 10

3.

Main Creek Lower Reach Lateral Creek Reach-1

HEC-RAS Plan: Prop Cond

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Main Creek Upper Reach 203 10-Year 2422.00 1424.80 1435.21 1435.63 0.012001 5.20 470.71 229.65 0.45

Main Creek Upper Reach 203 50-Year 3149.00 1424.80 1435.84 1436.35 0.012453 5.76 554.56 366.55 0.46

Main Creek Upper Reach 203 100-Year 3488.00 1424.80 1436.10 1436.67 0.012926 6.08 596.62 502.43 0.48

Main Creek Upper Reach 202.9 Lat Struct

Main Creek Upper Reach 202 10-Year 2422.00 1424.60 1434.03 1434.68 0.020306 6.47 374.54 317.22 0.60

Main Creek Upper Reach 202 50-Year 3149.00 1424.60 1434.36 1435.27 0.025752 7.69 415.69 387.07 0.68

Main Creek Upper Reach 202 100-Year 3484.77 1424.60 1434.48 1435.52 0.028217 8.21 433.91 413.50 0.72

Main Creek Upper Reach 201 10-Year 2422.00 1424.60 1432.71 1432.71 1433.87 0.008681 8.76 304.93 274.95 0.87

Main Creek Upper Reach 201 50-Year 3149.00 1424.60 1433.31 1433.31 1434.45 0.008004 8.95 415.63 311.75 0.82

Main Creek Upper Reach 201 100-Year 3484.77 1424.60 1433.51 1433.51 1434.68 0.008033 9.16 454.50 317.94 0.81

Main Creek Upper Reach 199 10-Year 2422.00 1421.75 1428.61 1429.93 0.006149 9.81 277.24 56.42 0.70

Main Creek Upper Reach 199 50-Year 3149.00 1421.75 1429.93 1431.32 0.005061 10.13 355.08 60.95 0.65

Main Creek Upper Reach 199 100-Year 3484.77 1421.75 1430.43 1431.87 0.004890 10.39 385.50 62.63 0.65

Main Creek Upper Reach 198 10-Year 2422.00 1421.51 1428.85 1426.44 1429.65 0.002992 7.67 358.77 62.49 0.50

Main Creek Upper Reach 198 50-Year 3149.00 1421.51 1430.17 1427.28 1431.06 0.002739 8.19 444.66 67.84 0.49

Main Creek Upper Reach 198 100-Year 3484.77 1421.51 1430.67 1427.65 1431.61 0.002711 8.46 479.00 69.55 0.49

Main Creek Upper Reach 8.5 Bridge

Main Creek Upper Reach 8.1 10-Year 2422.00 1421.03 1428.40 1429.37 0.003509 8.30 326.93 54.56 0.54

Main Creek Upper Reach 8.1 50-Year 3149.00 1421.03 1429.67 1430.80 0.003332 9.00 398.36 57.99 0.54

Main Creek Upper Reach 8.1 100-Year 3484.77 1421.03 1430.12 1431.34 0.003395 9.40 424.79 59.51 0.55

Main Creek Upper Reach 8 10-Year 2422.00 1420.96 1428.46 1429.28 0.002772 7.47 353.04 54.25 0.48

Main Creek Upper Reach 8 50-Year 3149.00 1420.96 1429.72 1430.71 0.002730 8.22 427.01 64.90 0.49

Main Creek Upper Reach 8 100-Year 3484.77 1420.96 1430.18 1431.25 0.002780 8.59 457.90 69.78 0.50

Main Creek Upper Reach 7.1 10-Year 2422.00 1420.80 1426.40 1426.40 1428.95 0.013206 13.42 201.04 41.66 1.00

Main Creek Upper Reach 7.1 50-Year 3149.00 1420.80 1427.51 1427.51 1430.37 0.011794 14.31 249.33 47.64 0.98

Main Creek Upper Reach 7.1 100-Year 3484.77 1420.80 1428.21 1428.21 1430.94 0.010022 14.10 288.83 66.39 0.91

Main Creek Upper Reach 7 10-Year 2422.00 1415.79 1427.40 1428.11 0.001499 7.32 415.64 62.73 0.38

Main Creek Upper Reach 7 50-Year 3149.00 1415.79 1427.97 1429.00 0.002091 8.93 452.87 68.68 0.45

Main Creek Upper Reach 7 100-Year 3484.77 1415.79 1428.30 1429.46 0.002294 9.52 476.37 72.46 0.48

Main Creek Upper Reach 6.5 10-Year 2422.00 1415.00 1427.46 1428.00 0.001391 7.45 593.69 101.19 0.37

Main Creek Upper Reach 6.5 50-Year 3149.00 1415.00 1428.08 1428.85 0.001888 8.96 659.46 111.01 0.44

Main Creek Upper Reach 6.5 100-Year 3484.77 1415.00 1428.45 1429.29 0.002040 9.49 701.12 117.47 0.46 wayne Typewritten Text

PROPOSED CONDITIONS UNNAMED AND TRIBUTARY WATERCOURSES

HEC-RAS Plan: Prop Cond (Continued)

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Main Creek Lower Reach 6 10-Year 3109.18 1414.80 1427.73 1427.80 0.000533 2.16 1440.72 174.39 0.13

Main Creek Lower Reach 6 50-Year 3625.79 1414.80 1428.49 1428.57 0.000554 2.30 1576.79 184.62 0.14

Main Creek Lower Reach 6 100-Year 3997.99 1414.80 1428.90 1428.99 0.000579 2.42 1653.73 190.68 0.14

Main Creek Lower Reach 5 10-Year 3109.18 1411.31 1427.47 1427.65 0.003807 3.48 905.19 148.13 0.21

Main Creek Lower Reach 5 50-Year 3625.79 1411.31 1428.23 1428.42 0.003561 3.56 1063.19 229.36 0.20

Main Creek Lower Reach 5 100-Year 3997.99 1411.31 1428.65 1428.84 0.003444 3.60 1159.51 235.33 0.20

Main Creek Lower Reach 4 10-Year 3109.18 1409.80 1425.79 1426.59 0.017124 7.17 433.37 51.01 0.43

Main Creek Lower Reach 4 50-Year 3625.79 1409.80 1426.41 1427.36 0.019106 7.79 466.05 87.83 0.46

Main Creek Lower Reach 4 100-Year 3997.99 1409.80 1426.77 1427.78 0.019846 8.13 513.28 164.86 0.47

Main Creek Lower Reach 3 10-Year 3109.18 1410.74 1422.31 1423.26 0.023294 7.94 401.24 84.44 0.52

Main Creek Lower Reach 3 50-Year 3625.79 1410.74 1422.94 1423.93 0.022056 8.02 457.22 105.28 0.51

Main Creek Lower Reach 3 100-Year 3997.99 1410.74 1423.31 1424.32 0.021564 8.09 503.27 149.17 0.51

Main Creek Lower Reach 2 10-Year 3109.18 1408.79 1421.99 1422.14 0.002325 3.09 1037.86 228.61 0.18

Main Creek Lower Reach 2 50-Year 3625.79 1408.79 1422.69 1422.84 0.002214 3.17 1215.86 272.37 0.18

Main Creek Lower Reach 2 100-Year 3997.99 1408.79 1423.10 1423.25 0.002153 3.21 1330.42 292.47 0.18

Main Creek Lower Reach 1 10-Year 3109.18 1404.50 1421.27 1413.25 1421.59 0.005004 4.55 703.98 126.85 0.25

Main Creek Lower Reach 1 50-Year 3625.79 1404.50 1421.97 1413.93 1422.31 0.005009 4.76 805.93 166.78 0.25

Main Creek Lower Reach 1 100-Year 3997.99 1404.50 1422.37 1414.39 1422.72 0.005008 4.87 878.10 190.03 0.26

Lateral Creek Reach-1 203 10-Year 245.00 1434.00 1436.83 1436.96 0.021137 2.84 86.17 756.86 0.43

Lateral Creek Reach-1 203 50-Year 318.00 1434.00 1437.08 1436.16 1437.22 0.022442 3.10 102.58 775.01 0.46

Lateral Creek Reach-1 203 100-Year 353.00 1434.00 1437.17 1436.27 1437.33 0.023108 3.22 109.68 782.26 0.47

Lateral Creek Reach-1 202.9 Lat Struct

Lateral Creek Reach-1 202 10-Year 229.18 1432.20 1435.49 1435.64 0.022793 3.12 73.40 651.86 0.46

Lateral Creek Reach-1 202 50-Year 277.68 1432.20 1435.72 1435.88 0.022235 3.20 86.64 724.03 0.48

Lateral Creek Reach-1 202 100-Year 299.77 1432.20 1435.82 1435.98 0.021878 3.23 92.69 741.20 0.48

Lateral Creek Reach-1 201 10-Year 229.18 1431.30 1434.94 1433.63 1435.02 0.005621 2.21 104.34 630.60 0.30

Lateral Creek Reach-1 201 50-Year 276.79 1431.30 1435.33 1434.13 1435.40 0.003787 2.14 130.04 680.74 0.26

Lateral Creek Reach-1 201 100-Year 292.22 1431.30 1435.47 1434.16 1435.54 0.003321 2.11 139.23 694.67 0.25

Lateral Creek Reach-1 200 10-Year 229.18 1429.25 1432.18 1432.18 1433.67 0.214077 9.76 23.47 173.23 1.00

Lateral Creek Reach-1 200 50-Year 276.79 1429.25 1432.58 1432.58 1434.26 0.221327 10.40 26.60 176.45 1.01

Lateral Creek Reach-1 200 100-Year 292.22 1429.25 1432.70 1432.70 1434.44 0.223415 10.59 27.59 177.46 1.01

HEC-RAS Plan: Prop Cond (Continued)

River Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)

Lateral Creek Reach-1 103.5 Culvert

Lateral Creek Reach-1 102 10-Year 229.18 1421.30 1427.76 1428.07 0.007399 4.43 51.69 41.78 0.31

Lateral Creek Reach-1 102 50-Year 276.79 1421.30 1428.51 1428.86 0.007506 4.80 57.64 44.15 0.32

Lateral Creek Reach-1 102 100-Year 292.22 1421.30 1428.92 1429.28 0.006927 4.79 61.00 45.49 0.31

Lateral Creek Reach-1 101 10-Year 229.18 1418.00 1427.88 1427.89 0.000185 0.57 403.55 83.13 0.05

Lateral Creek Reach-1 101 50-Year 276.79 1418.00 1428.65 1428.66 0.000173 0.59 472.68 97.16 0.04

Lateral Creek Reach-1 101 100-Year 292.22 1418.00 1429.07 1429.08 0.000152 0.57 515.51 105.55 0.04

Cole Grade Road Bridges Plan: Prop Cond

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Prop Cond

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Prop Cond

RS = 201

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Cole Grade Road Bridges Plan: Prop Cond RS = 200 Skew 40 degrees

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

0 100 200 300 400 500 600 700

Cole Grade Road Bridges Plan: Prop Cond RS = 103.5 Culv u/s xsec skewed 40 degrees, culvert not skewed

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04 .018 .04 .1 .04

20 30 40 50 60 70 80 90 100

Cole Grade Road Bridges Plan: Prop Cond RS = 103.5 Culv u/s xsec skewed 40 degrees, culvert not skewed

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

20 30 40 50 60 70 80 90 100

Cole Grade Road Bridges Plan: Prop Cond

RS = 102

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04

0 20 40 60 80 100 120 140 160 180

Cole Grade Road Bridges Plan: Prop Cond

RS = 101

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Bank Sta

.04 .1 .04

0 200 400 600 800 1000 1200

Cole Grade Road Bridges Plan: Prop Cond

RS = 203

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Cole Grade Road Bridges Plan: Prop Cond

RS = 202

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .1 .04 .1 .04 .018 .04 .1 .04

0 200 400 600 800 1000

Cole Grade Road Bridges Plan: Prop Cond RS = 201 Use prop GR left of Sta 292.40 and exist GR right of Sta 292.40

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

Ineff

Bank Sta

.04 .04 .04 .018 .04 .1 .04

0 20 40 60 80 100

Cole Grade Road Bridges Plan: Prop Cond

RS = 199

Station (ft)

E le va tio n (f t)

Legend

WS 100-Year

WS 50-Year

WS 10-Year

Ground

.04 .04 .04

Cole Grade Road Bridges Plan: Prop Cond RS = 198 Skew 41.65 degrees to…