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HomeMy WebLinkAboutDESN0698 Report.pdfI-405 / SR 167 Interchange Direct Connector Design Build Project DESN0698 Item No. 03 Document Date: 06/11/18 Document Type: DCPF Author: Subject: To To (Company):(Individual): From From (Company):(Individual): Schedule Activity: Yes No Distribution: Attachments Notes: 0 0 0 RFC: Revision RFI0282 - Rolling Hills Creek Technical Memorandum and Plans Revisions RFC Distribution Rachel Altona DOCUMENT CONTROL PROCESSING FORM File Number: Jacobs WSDOT Report and/or Keywords Additional Subject Information 0 PARSHOTAM AJUDIA N/A Eric Crowe SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ROLLING HILLS CREEK TECHNICAL MEMORANDUM I-405/SR 167 DIRECT CONNECTOR Rolling Hills Creek Technical Memorandum Washington State Department of Transportation WSDOT Northwest Region May 2018 Prepared by: Jonathan Turcott, PE 5-31-18 WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 2 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Stream and Fish Passage Summary The I-405/SR 167 Direct Connect Project (Project or Direct Connect) will widen SR 167 and I-405 and construct a new flyover bridge at the interchange to provide a direct connection between HOV lanes on each freeway. Rolling Hills Creek crosses I-405 and SR 167 in several locations shown in Figure 1, including through an existing 4’ wide x 3’ high box culvert crossing SR 167 at MP 25.93. This culvert identified as WSDOT Culvert 76 has been classified as a partial fish barrier and is being replaced by the Project. The new crossing location is approximately 800 feet south of the existing culvert crossing (SR 167 MP 25.77). This relocation will be accommodated by construction of approximately 1,350 feet of new stream, including habitat enhancements through an existing wetland (referred to as Rolling Hills Creek Wetlands). The new stream will run south and turn west to cross SR 167. The southern end of the new stream is bounded by a utility berm containing a 16-inch City of Renton water main relocated by the Project. The Panther Creek Wetlands lie to the south of the berm. A hydraulic connection between the two wetland areas will be provided by twin 36-inch culverts through the berm. Figure 1. Existing and Proposed Streams and Crossings in Vicinity of I-405/SR 167 Interchange. Ex. Rolling Hills Creek (daylighted), To be filled. Lower Rolling Hills Creek Rolling Hills Creek (in City storm pipe) Ex. Rolling Hills Creek Culvert Crossing. (C76) 4’ W x 3’ H Concrete box. To be repurposed as storm conveyance. Rolling Hills Creek Culvert Crossings (C42/C44) Rolling Hills Creek (daylighted) Upper Rolling Hills Creek Culvert (C49) Lower Rolling Hills Creek Culvert (C48) Thunder Hills Creek Culvert (C52) Panther Creek Wetlands Panther Creek Culvert (C72) Rolling Hills Creek Culvert (C47) Proposed (2) 36-inch culverts maintain hydraulic connection through utility berm Proposed Rolling Hills Stream Re-alignment Proposed Rolling Hills Creek Crossing (C76). 14’-2” Span x 9’8” H Upper Rolling Hills Creek WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 3 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 The new crossing location was chosen to align with the south edge of SW 19th Street (City of Renton). SW 19th Street is bordered to the south by a large wetland complex that runs approximately 800 feet west. The new Culvert 76 location allows for a potential future connection of daylighted stream and fish passable structures to the confluence with Springbrook Creek. After completion of the Direct Connect Project, Culvert 76 will terminate at a maintenance vault at the toe of a wall along Southbound SR 167. A pipe connection will be constructed between this vault and the 60-inch storm system in SW 19th Street. The connection is designed to control discharge rates to the City of Renton 60-inch storm and maintain existing water elevations in the wetlands east of SR 167. The existing, proposed and potential future alignments of Rolling Hills Creek are shown in Figure 2. Figure 2. Rolling Hills Creek Existing, Proposed and Potential Future Alignments. Project Commitments and Background The I-405/SR 167 Direct Connect Project is being delivered under a Design-Build contract administered by WSDOT. Prior to awarding the Design-Build contract, WSDOT obtained environmental permits for the I-405, Tukwila to Renton Improvement Project (I-5 to SR 169 Phase 2), which includes the Direct Connect Project. The permits were based on an initial Project footprint and the anticipated impacts. The Tukwila to Renton Finding of No Significant Impact (FONSI) and Final Section 4(f) Evaluation (July 2008) identified Culvert 76 as fish passable, but the original footprint for the Direct Connect included widening of the Northbound SR 167 to Northbound I-405 ramp, which would have resulted in filling Rolling Hills Creek and impacting the end of Culvert 76. A NEPA Re-evaluation related to the Direct Connect was prepared in August of 2015. It identified Culvert 76 as a partial fish passage barrier and a commitment was made to replace it. Federal Permanent Injunction No. C70-9213 (Injunction), dated March 29, 2013 obligates WSDOT to replace fish barriers within its rights-of-way. The initial prioritization of culvert replacements included WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 4 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 structures where project impacts triggered Hydraulic Project Approval from the State of Washington. The original configuration of the Direct Connect Project required filling of the existing Rolling Hills Creek channel adjacent to Northbound SR 167. Based on the current Project configuration, filling Rolling Hills Creek and impacting Culvert 76 is not required for roadway widening, but Rolling Hills Creek along SR 167 will be filled and Culvert 76 repurposed as a stormwater conveyance for the Project. The replacement represents an opportunity for WSDOT to remove a fish barrier from the injunction list, provide forward compatibility, and honors the commitment made in the NEPA Re-evaluation. The Project has also made several commitments to the City of Renton and agencies. WSDOT obtained a Critical Areas Permit from the City of Renton includes a condition to provide hydrologic and hydraulic analysis of the City’s SW 19th Street storm system including backwater effects from Springbrook Creek. The existing wetlands east of SR 167 serve as flood control for the City, attenuating flows to the 60-inch storm system in East Valley Road and SW 19th Street. The new stream system must match the water surface elevations in the wetland for the 2-year through 100-year storm events and match the existing flow rates to the downstream system. Additionally, a hydraulic connection to the Panther Creek wetlands must be maintained. Element 6 of this memorandum contains the detail of the analyses performed to satisfy the Critical Area Permit requirement. The Project is also required to perform an analysis of floodplain storage for a range of elevations below elevation 19.58. This is included in Element 11 of this memorandum. Design Guidelines A Preliminary Basis of Design (PBOD) was prepared by the WSDOT Eastside Corridors Team (I-405/ SR167 Interchange Direct Connector Project Preliminary Basis of Fish Barrier Mitigation Design, March 2015). This document is contained in Attachment ‘A’. The PBOD contains many of the design requirements, parameters, and methodologies that are included in more detail in this memorandum. Consistent with the requirements of the Injunction, the fish passage structure is designed using Stream Simulation methodology described in the 2013 Washington State Department of Fish and Wildlife (WDFW) Water Crossing Guidelines. The new stream segment design references the 2012 WDFW Stream Habitat Restoration Guidelines and the 2003 WDFW Integrated Streambank Protection Guidelines (2003) Other guidelines and standards have been referenced for specific elements in this memorandum. Rolling Hills Creek Existing Conditions Rolling Hills Creek is a highly modified urban stream located entirely within Renton, Washington. The stream begins as two tributaries identified as Upper Rolling Hills Creek and Lower Rolling Hills Creek. Upper Rolling Hills Creek originates south of I-405 along the east side of Talbot Road. It travels north in an open channel before entering an enclosed conveyance system at the intersection of South Puget Drive and Talbot Road. The enclosed system continues north and crosses I-405 in a 42-inch pipe identified as Culvert 49. This pipe continues north and intersects with a 72-inch pipe running west 750 feet adjacent to Renton Village Place. This pipe transitions to a 8-foot wide box culvert running southwest 500 feet to a daylighted stream section along Southbound I-405. Lower Rolling Hills Creek begins just south of Northbound I-405 in a wetland. It immediately enters a 48-inch culvert crossing I-405 (Culvert 48). The culvert discharges just east of the Upper Rolling Hills Creek box culvert. Based on review of past reports and studies, Rolling Hills Creek was originally one reach. The creek ran northwest across the current intersection of Puget Drive and Talbot Road and through the wetlands forming Lower Rolling Hills Creek. The daylighted segment of Rolling Hills Creek along I-405 runs approximately 650 feet to the Northeast quadrant of the I-405/SR 167 interchange. The primary flow is into a 48-inch culvert (Culvert 42) that WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 5 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 runs due west and then turns southeast toward the Southeast quadrant of the interchange. There is a secondary 11-foot diameter pipe (Culvert 44) set higher than the 48-inch pipe. It runs roughly due south and discharges at the same location as Culvert 42. This pipe functions as an overflow for larger storm events. At the discharge of Culverts 42 and 44, Rolling Hills Creek is again daylighted. It runs along a gabion- basket retaining wall supporting the Northbound SR 167 to Northbound I-405 ramp. The daylighted section runs south approximately 500 feet to Culvert 76. Culvert 76 is a 4ft wide by 3ft high concrete box culvert. It crosses SR 167 to East Valley Road where it intersects a 60-inch City of Renton Stormwater conveyance pipe. This pipe runs south approximately 680 feet to SW 19th Street where it turns west. The conveyance continues west approximately 2,200 feet to a small segment of open channel. This channel flows 350 feet where it merges with Springbrook Creek. The corridor proposed for the new stream segment is a large wetland complex confined by a steep hillside to the east and SR 167 to the west and north. It is bounded to the south by a utility berm containing a City of Renton water main. South of the berm are the Panther Creek wetlands. Panther Creek itself crosses SR167 in a recently constructed fish passable structure. The two wetland complexes are hydraulically connected by two 36-inch culverts through the utility berm. They are also both hydraulically affected by the water elevation in Springbrook Creek. The wetland complex along SR 167 appears to be what remains of a historic valley floor. The topography is somewhat varied. Portions of the wetland experience periods of persistent standing water. The vegetation consists mainly of grasses and deciduous trees. There are no coniferous trees within the floor of the wetland, though some are growing on the adjacent hillside. Springbrook Creek travels northwest toward the Black River, a side-channel to the Green River. The Black River Dam isolates Springbrook Creek from high flow and high tide conditions affecting the Green River. The dam contains a pump station call the Black River Pump Station. The pump station conveys all flows from Springbrook Creek through the Black River to the Green River. The pump station has an Alaska Steeppass (Denil) fish ladder allowing adult fish to migrate upstream and an airlift system allowing juvenile fish to migrate downstream. Otherwise, the pump station is a complete barrier to fish passage. Reference Reach Characteristics The only reference location for studying Rolling Hills Creek stream characteristics is the daylighted segment along I-405 (See Photo 1). SDA visited this location on March 2, 2017. The temperature was approximately 40 degrees and the rainfall for March 1st and 2nd totaled 0.11-inches. The reference location is a slightly meandering segment with a consistent width. It is stable channel with a mild trapezoidal bottom and nearly vertical or undercut banks supported by trees and other vegetation. The flow in the channel was approximately 6-feet wide and 6 to 8 inches deep (Photos 2 and 3). This would appear to represent baseflow depth in the stream. The bankfull width was measured at 10-feet (Photo 4). The overbank is defined by a grade break and tree line. This bankfull width is consistent with the determination in the Preliminary Basis of Design. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 6 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Photo 1. Reference Reach (Looking Downstream to the West). The streambed was primarily comprised of silt and sand with sections containing larger material. Because of the quantity of fine material in the streambed, it was difficult to grab representative samples, even in the sections with larger material. Photo 5 is a location of larger material containing sand and gravel. A rough estimate of the streambed material observed in place in Photo 5 is summarized in Table 1. Table 1: Streambed Gradation Estimates at Reference Location. Class Size Reference Stream Segment Diameter (inches) D16 Sand D50 0.25 D84 0.75 D100 1.25-1.5 WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 7 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Photo 2. Channel Bottom Measurement (Looking Upstream to the East). The channel and banks appear stable, but there is fine sediment accumulation in Culvert 44, the high flow bypass. This would indicate that the silt and sand is transported downstream during higher flow events. 6-feet WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 8 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Photo 3. Flow Depth Measurement. Photo 4. Bankfull Width Measurement (Looking Upstream to the East). 6.5 inches 10-feet WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 9 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Photo 5. Observed D100 , D84, D50, D16. D100 1.25-1.5 inches D84 0.75 inches D50 0.25 inches D16 Sand WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 10 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Stream and Fish Passage Structure Design The stream and fish passage structure design meets the requirements and guidance provided by the following reference documents: • WDFW Water Crossing Design Guidelines (2013) • WDFW Stream Habitat Restoration Guidelines (2012) • WDFW Integrated Streambank Protection Guidelines (2003) • FHWA Hydraulic Engineering Circular No. 18, Evaluating Scour at Bridges (HEC 18) • FHWA Hydraulic Engineering Circular No. 23, Bridge Scour and Stream Instability Countermeasures (HEC 23) Volumes I and II. • I-405 / SR 167 Interchange – Direct Connector Project Request for Proposal (RFP), Chapter 2, related contract commitments and environmental permits and Appendix H2 (Preliminary Basis of Fish Barrier Mitigation Design Memorandum), WSDOT (Revised November 2015) • Stream Simulation: An Ecological Approach to Providing Passage for Aquatic Organisms at Road-Stream Crossings (USDA/Forest Service2008). The Federal Injunction and permit documentation for the Project specify the Stream Simulation Culvert Design Option as outlined in Chapter 3 of the WDFW Water Crossing Design Guidelines. The intent of this method is to create and maintain similar stream processes within the fish passage structure as exist within a reference stream channel. In addition, the Project requires the construction of approximately 1,350 feet of new channel and habitat enhancements. The Project also has specific hydraulic analysis requirements and other considerations based on commitments made to the City of Renton and other agencies. The analyses for design of the fish passage and stream have been organized into 11 Elements: Element 1: Bankfull channel width and fish passage span Element 2: Proposed channel geometry Element 3: Fish passage configuration and dimensions Element 4: Channel and fish passage alignment and profile Element 5: Hydrology Element 6. Hydraulic Analysis Element 7: Determine substrate requirements for streambed Element 8. Channel aggradation and degradation mitigation and total scour Element 9: Large Woody Debris and Bioengineered Bank Protection Element 10: Stream Restoration Planting Considerations Element 11: Floodplain storage WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 11 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Element 1: Bankfull Channel Width and Fish Passage Span The Preliminary Basis of Design Memorandum calculated a bank full width (BFW) of 10.6 feet. SDA performed a site visit on March 2, 2017 to a reference location upstream and concur with this calculated width. Using Equation 3.2 from the WDFW 2013 Water Crossing Design Guidelines, a 10.6-foot bank full width requires a 14.7-foot fish passage span. Culvert span = BFW * 1.2 + 2 feet Equation 3.2 10.6 ft * 1.2 + 2 feet = 14.7 feet Element 2: Proposed Channel Geometry The design channel geometry matches the reference segment as closely as possible. SDA measured a mildly-sloped channel bottom 6-feet wide and a flow a depth of 6 to 8 inches. This corresponds to a bottom slope of 6 to 1. The banks are nearly vertical or undercut up to a point where the bank slope transitions to overbank. The channel will be constructed out of streambed mix and cobbles, which are rounded and not stable at slopes greater than 2 to 1. The overbank areas will have varying slopes between 3 to 1 and 6 to 1 and incorporate a planting bench described in Element 10. The thalweg (lowest point) of the channel will transition from the center toward the outer bank in meander bends. This will mimic channel form in natural streams. Element 3: Fish Passage Configuration and Dimensions Based on Element 1, the fish passage minimum span is 14.7 feet. The structure must provide an interior clearance of 5.5 feet, between the center of the channel bed and the inside top of the structure for maintenance (I-405/SR 167 Interchange Direct Connect Request for Proposal Section 2.14.4.11.1). The fish passage exits the SR 167 embankment perpendicular to East Valley Road which is at a much lower elevation than SR 167. Accommodating a future extension west across East Valley Road limits the type and dimensions of structure that can be used for the crossing. The chosen solution is an aluminum structural plate pipe arch summarized in Table 2. Table 2: Fish Passage Structure Shape and Dimension Culvert ID Required Culvert Span Culvert Type Dimensions Rolling Hills Creek 14.7-ft Aluminum Plate Pipe Arch 14’-11” Span x 9’-10” rise An interior height of 9’-10” is adequate to provide of 5.5 feet (minimum) clearance for maintenance and sufficient bed material to be placed in the bottom of the structure. The structure shape also minimizes the rebuilding of East Valley Road to provide cover over a possible future extension. Element 4: Channel and fish passage alignment and profile. The overall approach for design of the fish passage crossing is to understand the upstream and downstream channel conditions. Rolling Hills Creek is highly modified and urbanized. SDA studied an available reference location upstream. It may or may not represent a natural stream segment, but it does represent a stable, established stream section. Alignment The reference location contains some meander bends and thalweg transitions. The channel is designed to meander and the thalweg of the channel has been designed to migrate. The fish passage structure is WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 12 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 roughly perpendicular to the new stream. To accomplish this turn, a wide radius bend has been designed. Scour has been calculated to be zero for this bend, see Element 8. Profile The profile of the stream and fish passage is set by two controlling elevations. The downstream end of the fish passage streambed is set at elevation 11.13 feet and the upstream end of the stream is set at the invert elevation of Culvert 42 (15.40 feet). The slope of the new stream is approximately 0.27% and the fish passage bed slope is 0.29%. The reference reach slope is approximately 0.31%. The slope ratio (proposed fish passage bed slope/reference reach slope) is 0.97.In the reference Reach, there are sections of very fine material separated by smaller pockets of sand and gravel material. The presence of large beds of silt and sand separated by bands of sand and gravel suggest that some riffle-pool characteristics are present. The new stream channel will exhibit similar characteristics. Transitioning the thalweg toward the outside of the channel flattens the slope creating pools. Riffles have been added by providing coarse material at the transitions out of bends. Element 5: Hydrology The hydrology used for analyzing the design of the Rolling Hills Creek channel is summarized in the document, Preliminary Hydraulic Analysis for Rolling Hills Creek Alignment (Preliminary Hydraulic Analysis), which is included in Attachment ‘C’. The City of Renton prepared HSPF models for the 2- year through 100-year events for several locations throughout the Rolling Hills Creek system. Per the Project requirements, no other hydrology models may be used for the design of the stream and fish passage. There are two HSPF models, an existing condition and a future flow condition. The future flow condition is considered the baseline for analysis of the stream and fish passage design. Table 3 contains the HSPF flows and the reach locations where they are input into the HEC-RAS hydraulic model. Table 3: Rolling Hills Creek Design Flows Location Reach ID (HEC- RAS Station) Recurrence Interval Flow Rates (cfs) 2-year 10-year 25-year 50-year 100-year Outlet from Culverts 42 and 44 103 (5580) 63.9 84.6 93.5 99.7 105 Inlet to Existing Culvert 76 and upstream of new fish passage 102-1 (3736/3016) 81.2 109 123 133 143 19th Street Storm System 11 (2751) 98.3 117 123 126 129 The flow input location for Reach 103 is the downstream end of Culvert 42 and Culvert 44. The flow input location for Reach 102-1 is within the Rolling Hills Creek wetland, just upstream of the existing Culvert 76 location. The flow input location for Reach 11 is downstream in the City of Renton 60-inch storm network. There is a hydraulic connection between the Rolling Hills Creek wetlands and the Panther Creek wetlands via twin 36-inch pipes crossing and existing utility maintenance berm. This berm is being relocated south to accommodate a new 16-inch water line, and the hydraulic connection will be maintained by two new 36-inch pipes. This flow split is not reflected in the HSPF flowrates in Table 3. The hydraulic analysis Element contains further discussion how this split is modeled in HEC- RAS. The water surface elevations in Springbrook Creek and the Panther Creek Wetlands affect the hydraulics of Rolling Hills Creek. The Preliminary Hydraulic Analysis references the East Side Green River Watershed Plan Technical Memorandum Supplement – Final (City of Renton, February 2007). WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 13 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 This study modeled Springbrook in HEC-RAS to develop water surface elevations for Existing and Future Land Cover conditions. It also included analysis for storage and conveyance scenarios, which correspond whether or not the Black River Pump Station is operating. The water surface elevations used in this memorandum are the future land cover and conveyance condition1. The HEC-RAS models also use the Panther Creek Wetland water surface elevations. These elevations are provided under scenario 17 in the Memorandum Thunder Hills Creek Mitigation – Panther Creek Wetland Fish- Passable Culvert (NHC 12/30/11). Table 4 contains the water surface elevations for each recurrence interval. These water surface elevations are input as known water surface boundary conditions in the Rolling Hills Creek HEC-RAS models. Table 4. Tailwater Elevations for HEC-RAS Analysis. Springbrook Creek Scenario Elevation at Recurrence Interval (ft. NAVD 88) 2-year 10-year 25-year 50-year 100-year Springbrook Creek Future + Conveyance 13.0 14.2 14.9 15.0 15.3 Panther Creek Wetland 15.3 16.7 17.6 17.8 18.7 Element 6: Hydraulic Analysis Attachment ‘D’ contains the hydraulic analysis. The existing and proposed Rolling Hills system was analyzed in HEC-RAS by WSDOT during Project environmental permitting. The development of those models is summarized in the Preliminary Hydraulic Analysis. This final design memorandum provides a verification and refinement of those models. The Project is required to meet several requirements related to hydraulics: 1. Zero Rise in the FEMA mapped floodplain (pre- versus post-project backwater using HEC-RAS) 2. Matching flow rates (pre- versus post-project) in the 19th Street system. 3. Wetland connectivity to Panther Creek Wetlands. 4. Hydraulic Analysis for the Rolling Hills Creek fish passable structure, including backwater analysis. These requirements are analyzed using modified versions of the Existing and Proposed condition HEC- RAS models obtained from WSDOT. Existing Model The Existing Model was developed using a combination of field survey and as-built information. The model includes an Upper Reach, Wetland Reach and Lower Reach. The Upper Reach begins at the upstream end of the daylighted section of Rolling Hills Creek adjacent to I-405. It continues downstream through Culvert 42 and 44 (modeled as multiple pipes) and in the daylighted section along SR 167. The Upper Reach ends at Culvert 76. The Wetland Reach splits from the Upper Reach at Culvert 76 (HEC-RAS Station 3676). The wetland is modeled south and includes the utility berm. The primary outlet from the utility berm is twin 36-inch 1 The Preliminary Hydraulic Analysis stated that the future Springbrook Creek elevations were used in the HEC- RAS analyses, but the future flow boundary conditions used the existing water surface elevations. The current model reflects this updated condition. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 14 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 culverts, which are included in the model. The existing utility berm also overtops during high flow events. The Lower Reach begins at the upstream end of Culvert 76 and continues south through the 60-inch storm system in East Valley Road and SW 19th Street. The end of the Lower Reach is the confluence with Springbrook Creek. The split between the Lower Reach and Wetland reach was added as a junction in HEC-RAS. To accurately model this split, the flow optimization routine was run. The sum of the resulting flows from the optimization routine match the HSPF flows in Table 3. Proposed Model The Proposed Model from the Preliminary Hydraulic Analysis has been renamed “Post Project”. It contains Upper, Wetland and Lower Reaches. The Upper Reach in the Post Project Model starts at the same upstream location as the Existing Model. South of Culverts 42 and 44 it models the new stream segment and ends just before the new fish passage structure. The Wetland Reach splits from the Upper Reach just upstream of the new fish passage structure. The wetland is a short segment defining the new utility berm containing twin 36-inch culverts. The new utility berm does not overtop during high flow events. The Lower Reach begins at the upstream end of the new fish passage structure. It transitions to a 48- inch helical corrugated metal pipe (Mannings n=0.020) with the bottom 5 inches filled with grout. This pipe connects to the 60-inch storm system in 19th Street. The remaining Lower Reach matches the Existing Model. Modifications from Preliminary Models Some modifications were made to the Existing and Post Project Models. These include changes to Springbrook Creek tailwater for both models and geometry data for the Post Project Model. The flow data changes address the water surface elevation discrepancies described in Element 5. In the Post Project Model, the geometry modifications include modifying the stream cross-section geometry, adjusting the profile, adjusting the length of the proposed fish passage and redesigning the 48-inch pipe connection to SW 19th Street. Due to reduced widening requirements, the fish passage length is shorter than the preliminary design. The preliminary design used a Manning’s coefficient of 0.03 for the main channel, which is suitable for minor streams with some grass or weeds or excavated channels with a gravel bottom (2015 WSDOT Hydraulics Manual Appendix A4-1). The 2015 WSDOT Hydraulics Manual recommends adding 0.01- 0.02 to the coefficient for irregular sections with slight meander and pools. The Post Project Model uses 0.05 for the main channel. Modeling Results The HEC-RAS modeling results are contained in Attachment ‘D’. Included are output tables, water surface profiles and cross-sections. The flow optimization routine was run, similar to the Preliminary Hydraulic Analysis. The results are slightly different in both the Existing and Post Project Models due the corrections made to the boundary condition water surface elevations and final geometry. Zero Rise Analysis This analysis is a comparison of the Existing and Post Project Water Surface elevations in the Rolling Hills Creek Wetlands. The Wetland location in the Existing Model is the Wetland Reach Stations 4279 to 4902. The Wetland location in the Post Project Model is the Upper Reach Stations 4541-5746. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 15 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Table 5. Summarizes the Existing and Post Project Wetland elevations. Note these elevations are representative and vary slightly depending on reach station. Table 5. Existing versus Post Project Rolling Hills Creek Wetland Water Surface Elevations. Model Elevation at Recurrence Interval (ft. NAVD 88) 2-year 10-year 25-year 50-year 100-year Existing 18.36 19.42 19.98 20.25 20.61 Post Project 18.36 19.13 19.65 19.86 20.12 The table shows small changes in water surface elevation between existing and proposed conditions. The critical 100-year water surface elevation is reduced. The 2-year shows the same water surface elevation Downstream Flow Comparision This analysis compares flow rates to the 19th Street storm drainage system. The point of comparison are the upstream ends of Existing and Post Project Culvert 76. These correspond to stations and 3676 and 3003, respectively. Table 6 summarizes the downstream flow rates. Table 6. Existing versus Post Project Flow Rates to 19th Street. Model Flow Rate at Recurrence Interval (ft. NAVD 88) 2-year 10-year 25-year 50-year 100-year Existing 69.11 72.37 70.81 73.26 73.93 Post Project 65.26 72.27 70.13 73.08 73.81 The table shows reduction in flow rates between existing and proposed conditions for all recurrence intervals. Wetland Connectivity This analysis compares flow rates to the Panther Creek Wetlands for the Existing and Post Project Models. The point of comparison are the upstream ends of Existing and Post Project Culvert 76. These correspond to Wetland Reach station 4227 in the Existing Model and Wetland Reach station 53 in the Post Project Model. Table 7 summarizes the flow rates to the Panther Creek Wetlands. Also included is a sum of Post Project flows for comparison with the HSPF flow rates modeled to Culvert 76. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 16 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Table 7. Existing versus Post Project Flow Rates to the Panther Creek Wetlands. Model Flow Rate at Recurrence Interval (ft.) 2-year 10-year 25-year 50-year 100-year Existing 12.09 36.63 52.19 59.74 69.07 Post Project 15.74 36.73 52.87 59.92 69.19 Sum of Post Project Flows 81 109 123 133 143 The table shows a small increase for all flows. Additional Scenarios Two other hydraulic scenarios were considered. Both are a prediction of system hydraulics for the potential daylighting of Rolling Hills Creek to Springbrook Creek. The scenarios use two sets of hydrology data. The post-project geometry was modified to remove the downstream pipes and structures in SW 19th Street, and the channel modification tool in HEC-RAS was used to fit a template trapezoidal cross-section similar to the Project cross-section. The wetland southeast of the intersection of SW19th and East Valley Road was modeled as a flat overbank area at elevation 15. The Panther Creek Wetland junction at the utility berm were removed from the geometry, because in the future condition, the modeled water surface would not reach the elevation of the twin 36-inch culverts crossing the utility berm (Elevation 17.0). One scenario analyzes the 2-year through 100-year future flow and boundary conditions (tailwater elevation in Springbrook Creek). This scenario is used for streambed design and scour analysis and calculating 100-year clearance. 100-year event water surface elevation does not exceed 17.0 feet, the elevation of the twin 36-inch culverts to the Panther Creek Wetlands, so the flow split is removed from the model and the full future HSPF flows (Table 3) are modeled to Culvert 76 (Reach ID 102-1) and 19th Street (Reach ID 11). The calculated 100-year clearance is approximately 2.7 feet. This potential future condition exceeds WDFW guidance which recommends 2 feet of clearance. The other scenario is an analysis of monthly average flows for October and March. The daylighted geometry was used and the monthly flows with Springbrook Creek tailwater elevations were analyzed. This scenario is used for assessing the flow depth for bioengineered bank protection. Fish Passage The stream simulation design method is used to support and maintain natural stream processes: “Stream simulation is based on the principle that if fish can migrate through the natural channel, they can also migrate through a man-made channel that simulates it. Taking this approach eliminates the need to consider the swimming characteristics of individual species of fish…” (Barnard 2013). The channel cross-section and profile have been designed to simulate the reference section upstream. Element 7: Determine Substrate Requirements for the Streambed. The Rolling Hills Creek system is hydraulically affected by the tailwater elevation in Springbrook Creek. This relationship results in a low energy system. The streambed material in the reference section is silt and sand with pockets of larger material. During higher flow events, it appears that the finer material is transported downstream. This is evident from sediment deposited at the entrance to Culvert 44. The coarser sand and gravel does not appear to be transported. For the new stream construction (outside of the fish passage), the Design-Build team has specified Modified Streambed Sediment as an WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 17 SDA 1724 W. Marine View Drive, Suite 140 E v e r e t t , W A 9 8 2 0 1 P: 425.486.6533 F: 425.486.6593 appropriate material gradation when compared with the coarser bed areas of the reference section. Table 8 provides a comparison of observed streambed gradation and Modified Streambed Sediment. See Attachment ‘E’ for more information on Modified Streambed Sediment. Table 8: Modified Streambed Sediment Gradation Compared to Reference Section. Sieve Size Percent Passing (Dx) Observed Gradation (inches) 1.5 “ 99-100 (D100) 1.25-1.5 1.25” 89 (D84) 0.75 0.75” 57 (D50) 0.25 No.4 33(D16) Sand No. 40 8 No. 200 4 Note: Per Aggregate Submittal Attachment ‘E’ In riffles, the mix is modified by the addition of 4-inch streambed cobbles with a mix ratio of 70% 4-inch streambed cobbles to 30% modified streambed sediment. This will produce a mix primarily consisting of 1 to 2 inch pebbles. Fish Passage Structure Streambed Mix In the post-project condition, the energy and the flow rate to the fish passage are reduced based on the flow split to the Panther Creek Wetlands and the backwater-effect from the flow restricting pipe downstream. The streambed in the fish passage has been designed for the potential daylight of the channel to Springbrook Creek because this is a higher flow and higher energy condition. One method for determining a stable particle size is based on a comparison of calculated shear stress versus stable shear stress for a particle. A methodology for performing this analysis is contained in Stream Simulation: An Ecological Approach to Providing Passage for Aquatic Organisms at Road- Stream Crossings (USDA/Forest Service2008). Equation E.1 from the USDA document calculates the boundary shear stress: t = γRS Equation E.1 Where t is the boundary shear stress for the 100-year event, γ is the specific weight of water (62.4 lb/ft3), R is the Hydraulic Radius, S is the energy slope. The energy slope and hydraulic radius are 100-year outputs from the cross-section just upstream of the fish passage structure (HEC-RAS Sta. 3003) from the Future Daylight HEC-RAS scenario. Table 9a: Equation E.1 Inputs and Results Culvert IDs Inputs t (lb/ft2) R (ft) S (ft/ft) Rolling Hills Creek Crossing 3.14 0.000935 0.1832 WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 18 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Section E.1.2 from the USDA document recommends identifying the flow at which the D84 or D95 particle is moved. For added stability, equation E.4 of uses the Shield’s parameter to calculate expected critical shear for the D50 particle size. tc = t*102.6D Equation E.4 rearranged to solve for D. Where tc is the shear stress calculated from Equation E.1, t* is the Shield’s parameter assumed to be 0.045, D = D50 particle size (ft.) x 12 (in/ft) Table 9b: Equation E.4 Inputs and Results Culvert IDs Inputs D50 (in.) tc (lb/ft2) t* (constant) Rolling Hills Creek Crossing 0.1832 0.045 0.48 To provide a streambed mix that mimics a natural distribution, the remaining diameter percentiles (D16, D84, and D100) are estimated using Equations 3.6, 3.7, and 3.8 provided in the WDFW Water Crossing Guidelines. These equations provide the following ratios: D84 / D100= 0.4 Equation 3.6 D84 / D50= 2.5 Equation 3.7 D84 / D16= 8.0 Equation 3.8 The calculated particle size distribution is shown in Table 10. Table 10: Calculated Particle Distribution for Rolling Hills Creek Crossing Diameter Percentiles Inches D100 3.00 D84 1.20 D50 0.48 D16 0.15 Table 11: WSDOT 4-inch Streambed Cobbles Approximate Size Percent Passing 4” 99-100 2” 70-90 1 ½” 20-50 ¾” 10 max. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 19 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Table 12: Proposed Streambed Mix Ratio Culvert IDs Percent Modified Streambed Sediment Percent 4-inch Streambed Cobbles Rolling Hills Creek Crossing 80% 20% Figure 3 compares the proposed streambed mix with the analyzed gradation. The design streambed mix will consist of 80% modified streambed sediment (Table 8) and 20% 4-inch cobbles per WSDOT Standard Specification 9-03.11(2) (Table 11). The proposed streambed mix ratio is contained in Table 12. This mix is specified for the channel bottom inside the fish passage. The proposed streambed mix is larger than the sediment observed in the reference reach, but it represents a different hydraulic condition where energy is increased. The mix ratio is a starting point for the contractor. It is important that the final streambed contain no voids that would allow the streamflow to go to the subsurface. The design plans specify that finer material be washed through the culvert until the voids are filled and the stream flows on the surface. Figure 3. Comparison of Streambed Sediment Distributions The Stable Particle Distribution in Table 10 indicates that the final mix should have 80% of particles between 0.1 inches and 2 inches. Note that the design mix is plotted as a percentage finer by weight. The streambed is modified to 70% 4-inch cobbles and 30% modified streambed sediment along the banks inside the fish passage. This is intended to roughen the overbank area to reduce the potential for the stream migrating to the walls of the structure. Similarly, coarse bands have been added at 50 feet on center perpendicular to the channel. These are also specified to be 70% 4-inch cobbles to 30% modified streambed sediment. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 20 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Element 8. Channel Aggradation and Degradation, Migration and Total Scour The design substrate within the structure is designed to be stable at the 100-year design flow (143 cfs) for a uniform stream segment. There are three conditions that could affect the long-term stability of the channel. The first potential stability concern is aggradation. Aggradation occurs when sediment transport from upstream areas is deposited when it reaches a location of lower energy flow. This could be expected where there is upstream erosion or potential for erosion due to bank instability or a steep (high velocity) channel profile. This condition is not expected to occur. There is no evidence of significant erosion or erosion potential directly upstream. Some fine sediment is transported during higher flows, but it appears to be a minor condition. The second potential stability concern is lateral migration. The energy in the system is low, so this is not expected. Large woody debris structures have been placed at the end of bends, which will serve to maintain the design meander. Another condition is where the channel section characteristics are not uniform, allowing erosion to occur on one bank and deposition to occur on the opposite bank. Examples of non-uniformity in channel include a difference in bank slopes, roughness, and resilience (or softness) of the bed material. In higher energy conditions, this could be a concern along the right bank parallel to the Olympic Pipe Line. This would result in the channel alignment shifting toward the eroded bank. The streambed mix is uniform across the channel. Toe logs and spurs have been added along the straighter segments parallel to the OPL line. This will increase roughness and force the channel away from the bank. The final condition where lateral migration could occur is where there is a remnant channel adjacent to the existing channel. The channel is entirely new, so this is not expected. Total Scour has been analyzed for the Rolling Hills Creek crossing. Total Scour for highway crossings is defined by FHWA HEC 18 as: 1. Long term degradation of the river bed 2. Contraction Scour at the bridge (fish passage) 3. Local scour at piers or abutments Degradation This condition could occur when there is a loss of sediment downstream and within the subject reach that is not replaced by sediment from upstream. The consequence is the reach will scour until it reaches an equilibrium slope. This could be expected where the downstream stream profile is significantly lower, steeper or has mechanisms that will cause it to be lower or steeper in the future. If the downstream system is daylighted in the future, the slope downstream will roughly match the post- Project Rolling Hills Creek and new Culvert 76 slopes. Also, the system downstream is controlled by backwater from Springbrook Creek, which sets the energy grade line for the system. Contraction Scour Contraction scour at the entrance to the culvert can occur when the crossing is narrower than the width of the approaching flow. Equation 6.1 from HEC-18 determines whether the scour is live-bed or clear- water. The distinction is whether or not material is transported in and out of the reach. In the case of the Rolling Hills Creek Crossing, the scour mode is clear-water, meaning no sediment transport occurs. The clear-water scour equations from HEC 18 (Equations 6.4 and 6.5) have been used to estimate contraction scour. The clear water scour calculations are contained in Attachment ‘F’. The clear water scour calculations determine an expected depth based on flow rate and streambed material size and compare it to the calculated depth in the contracted section. As a worst case, the Future Open WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 21 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Channel 100-year model depth was used, because it has reduced backwater effects and flow will not split to the Panther Creek Wetlands. The calculated contraction scour depth is 0.41 ft. The fish passage will be filled with a minimum of 3.10 feet of streambed mix, so sufficient material will remain in the structure. Engineering judgment would predict that there is some acceleration into the fish passage structure may not be reflected in the calculations. Quarry spalls have been provided along the banks leading up to the culvert opening and in front of the invert of the fish passage to mitigate this potential. Local (Abutment) Scour Abutment scour is caused by acceleration and/or turbulence around an object projecting into the flow. It has been assumed that there is zero abutment scour. For additional protection, Quarry Spalls will be placed on the roadway embankment and on the streambanks to a distance of 25 feet from the fish passage opening. The fish passage streambed mix will also extend 25 feet beyond the end of the fish passage. Rip-rap sizing for abutment protection has calculated using Design Guideline 14 from HEC 23 Volume II. The design D50 is 0.18 feet (2.16 inches); the D50 for Quarry Spalls is 3.83 inches. Bend Scour The smallest radius bend is just upstream of the crossing. It has a radius of 145 feet. Using the Thorne Equation (Equation 14, WDFW Stream Habitat Restoration Guidelines), the scour is 0.01 feet. A minimum of 2 feet of streambed mix is provided in the channel. Scour calculations are included in Attachment ‘F’. Element 9 Large Woody Debris and Bioengineered Bank Protection Large Woody Debris Structures and Bioengineered Bank Protection systems have been provided to mitigate the potential for erosion and to improve the habitat functions and values. The Project requirements include the following minimum standards for woody debris placement in the Rolling Hills Creek Stream corridor: For each 100 linear feet of channel, the channel design shall meet or exceed the following distribution of LWM: • Number of LWM pieces: 10 • Volume of LWM: 600 cubic feet • Number of key pieces: 2 LWM is defined as pieces exceeding 4 inches in diameter and 6.5 feet in length. A key piece is defined as pieces exceeding 18 inches in diameter and 20 feet in length. These requirements are consistent with Table 3 of Technique 7 (reproduced from Fox and Bolton contained in the study 2012 Stream Habitat Restoration Guidelines (WDFW). This table summarizes volume and quantities of wood expected in Western Washington streams. The Project requirements for total pieces, key pieces and volume are greater than the median value in Table 3. It is important to note that Table 3 identifies the volume and key piece quantities by bankfull width class at a range of 0- 30m (98 feet). Large Woody Debris Design Quantity The proposed design faces some challenges related to woody debris configuration and anchoring. The structures are expected to be fully submerged at times. This limits the opportunity to build large brush pile structures which provide excellent habitat benefits. A unique approach has been developed for this project. The proposed design provides 15 brush pile structures providing approximately 500 cubic feet of volume each (185 sf base x 2.7 ft high). They include a three-log base structure with at least one key piece including a rootwad. The cavity in the base structure will be filled with a variety of smaller branches and logs and a four-log lattice will then be placed over the brush and cabled to the base WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 22 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 structure. This configuration allows for a diversity of wood material while limiting the potential for brush to dislodge from the pile and travel downstream. The majority of the brush piles are located on the downstream end of bends. The rootwad is designed to touch the thalweg. See Figure 4 for the configuration of the brush pile structures. Figure 4. Brush Pile Configuration There are additional three log structures placed at random in the stream corridor. The 6 three-log structures provide 6 key logs and 18 total pieces. The stream channel is 1,400 feet long. The brush pile structures themselves provide 7,500 cubic feet of volume. This equates to approximately 536 cubic feet per 100 feet of stream. The bioengineered bank provides 7.7 cubic feet per toe log and 35.3 cubic feet per key log for a total of 58.4 cubic feet. There are 36 toe logs and 12 key logs in the bioengineered banks. This equates to 700 cubic feet, or 50 cubic feet per 100 feet. The 3-log structures provide 63.6 cubic feet of volume. The summary of LWD piece and volume counts is contained in Table 13. Table 13. Large Woody Material Summary Structure LWD Counts Key Pieces per Structure Smaller Pieces per Structure Structure Count Total Key Pieces Total Pieces (Key+Smaller) Volume Per Structure (cf) Total Volume (cf) Brush Piles 1 6 15 15 105 5001 7,500 3-log Structures 1 3 6 6 18 64 384 Bioengineered Bank 1 3 13 13 52 58 754 Additional 1 0 3 3 0 70 210 Totals 37 175 8,8488 Per 100 ft 2.6 12.5 632 1. Volume for structure is estimated using plan area of the exposed structure times the average height. Bioengineered banks line the straighter stream sections that are closest to the Olympic Pipe Line. The proposed biotechnical engineering feature is a log toe with key pieces placed approximately 60 feet on WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 23 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 center. The key pieces have rootwads and are angled down and buried into the bank. The toe logs are tied to each other and tied to the key pieces. The downstream end of each toe log will be partially buried. The key pieces extend to the thalweg of the channel. HEC 23, Volume I, Section 6.8 provides guidance for design and sizing of biotechnical engineered bank protection. The guidance recommends log structures that provide bank protection for the toe stage and the splash zone. The toe stage is defined as being under water more than 6 months out of the year. The splash zone is the area between the normal low water and normal high water. The guidance recommends logs be place in this zone for biotechnical bank protection. In the case of Rolling Hills Creek the observed flow depth at the bank toe is zero. The monthly average flow depth for the highest 6 months is approximately 0.8 feet deep at the thalweg of the channel (See HEC-RAS Analysis for Future Daylight October and March Mean Flows). This equates to 0.3 feet of depth at the bank. 8-inch logs provide suitable bank protection for the monthly average flow conditions. A biodegradable erosion control blanket (coir) has been specified for the zone 1-foot inside of the toe of the bank up to an elevation 2 feet above the channel thalweg or just above the bankfull depth. Large Woody Debris Brush Pile Anchoring Design The stream restoration design includes the placement of LWD Brush Piles adjacent to the stream channel. LWD Brush Piles consist of three large logs in a triangular configuration with four smaller logs in a lattice configuration. The base structure consists of one 18-inch diameter by 20-feet long log with rootwad, one 12-inch diameter by 20-feet long log, and one 12-inch by 16-feet long log. The smaller logs in the lattice are 6-inches diameter by 16-feet long. The cavity within the structure is filled with woody material. See the LWD Brush Pile and Bank Protection Details in Attachment ‘B’. Large Woody Debris Brush Pile Buoyancy Safety Factor In the post-Project condition, the 100-year water surface elevation is expected to fully submerge most of the brush pile structures. Buoyancy has the potential to cause failure by lifting the LWD off of the streambed and embankment, allowing it to be carried downstream. Buoyancy is resisted by LWD Brush Piles using MANTA RAY® MR-1 anchors at each of the lashing locations of the base structure. Per the manufactures specifications and the assumed soil condition the loading capacity of each MR-1 anchor is 8-12 kips. For anchoring calculations, the rootwads are assumed to be 3-feet diameter by 2- feet log cylinders with 40% void space. The buoyancy calculations also assume 40% void space for the woody material within the structure. Based on the calculations, the safety factor for buoyancy is 2.55. See Attachment ‘G’ for the LWD Anchoring Calculations. Note that the anchoring design for the simplified three-log structures will match the brush pile base structure, so separate calculations are not provided. Bioengineered Bank Protection Anchoring Design The stream enhancement design includes the placement of LWD Bioengineered Bank Protection along the bank of the stream channel. The Bioengineered Bank Protection shall consist of 8-inch diameter by 20-feet logs connected end-to-end laterally along the stream bank as well as 18-inch diameter by 20- feet long logs perpendicular to the channel with rootwads in the stream channel at 60-feet intervals, on center. Both key logs and longitudinal logs are anchored. Bioengineered Bank Protection Buoyancy Safety Factor The bioengineered bank protection is expected to be fully submerged during the 100-year event. Buoyancy has the potential to cause failure by lifting the LWD off of the streambed and embankment, allowing it to be carried downstream. Buoyancy is resisted by burying the majority of the key logs and adding MANTA RAY® MR-1 anchors. The rootwads are assumed to be 3-feet diameter by 2-feet log cylinders with 40% void space. The parallel logs are lashed to each other and to each key log and anchored. See the LWD Brush Pile and Bank Protection Details in Attachment ‘B’. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 24 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Each log is assumed to resist the buoyancy force on itself and 3 of the 8-inch diameter logs, with the exception of the most upstream and downstream trunks. The trunk furthest downstream resists the buoyancy force on itself and 3.5 of the 8-inch diameter logs. The trunk furthest upstream resists the buoyancy force on itself and 1.5 of the 8-inch diameter logs. The factor of safety for buoyancy achieved by the design is 28.6. The moment on the key logs was also checked. It is negligible and resisted by the anchors. See the Bioengineered Bank Protection Buoyancy Calculations included in Attachment ‘G’ Bioengineered Bank Protection Slipping Safety Factor Because the logs will be buried at a downward slope, buoyancy also has the potential to cause failure by lifting and “slipping” the LWD out of the embankment. Slipping is resisted by the skin friction between the trunk of the logs and the embankment. The factor of safety for slipping achieved by the design is 9.1. See the Bioengineered Bank Protection Slipping Calculations included in Attachment ‘G’ Cable Strength The LWD structures will be lashed together and tied to the anchors with ¼-inch EIPS (stainless steel) wire rope. Two ends of cable will be looped through each anchor. The total tensile strength of 2 ropes is 11.6 kips, which exceeds the anchor resistance of 8 kips. Element 10 Stream Restoration Planting Considerations Please see the Rolling Hills Creek Stream Restoration Planting Concept Memorandum, provided separately. Element 11 Floodplain Storage The Project requirements include accounting for floodplain volume for the following ranges: • 5 feet to 14 feet • 14 feet to 15 feet • 15 feet to 16 feet, and • 16 feet to 19.58 Floodplain fill volume calculations are based on the entire Direct Connect Project including highway widening. Additional floodplain is added by the Project by excavating the Rolling Hills Creek channel and reducing the dead storage in the wetland. In the existing condition, the permanent pool elevation in the wetland is at elevation 17.0, based on the bank elevation along the existing Rolling Hills Creek channel. In the post-Project condition, the bank elevation is reduced to approximate elevation 15.5, which will increase flood storage by 1.5 feet in the wetland. There is an increase in floodplain storage for all elevation ranges. See Attachment ‘H’ for the methodology and calculations. WSDOT Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum 25 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Attachments Attached with this memo, please find the following documents: • Attachment ‘A’ – WSDOT Preliminary Basis of Design Memorandum for Rolling Hills Creek Crossing” • Attachment ‘B’ – Rolling Hills Creek Plans (Plan, Profile, and Details) • Attachment ‘C’ – Hydrology • Attachment ‘D’ – HEC-RAS Hydraulic Analysis • Attachment ‘E’ – Streambed Mix Design • Attachment ‘F’ – Scour Calculations • Attachment ‘G’ – LWD Anchoring • Attachment ‘H’ – Floodplain Storage WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘A’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘A’ WSDOT Preliminary Basis of Design Memorandum for Rolling Hills Creek Crossing March 2015 (Rev Nov 2015) TO: Casey Kramer, State Hydraulics Engineer 360-705-7262 THRU: William James, Eastside Corridors Engineering Manager 425-450-2550 FROM: Alan Black / Ross Fenton 425-450-2515 / 425-456-8538 SUBJECT: I-405/ SR167 Interchange Direct Connector Project Preliminary Basis of Fish Barrier Mitigation Design Introduction Project Overview The I-405/ SR167 Interchange Direct Connector Project (Project) site is located on I-405 in the vicinity of the SR 167 and SR 515 interchanges within the City of Renton, Washington. The Project is part of the overall I-405 Tukwila to Renton Improvement Project that includes consideration of existing fish barriers within the project limits. The Project will construct a new direct connector ramp for a high occupancy vehicle (HOV)/express toll lane (ETL) in each direction between SR 167 south leg HOT lanes and I-405 north leg HOV lanes. Included is reconstructing sections of I-405 and SR 167 to open up the medians to make room for the new direct connector ramp; constructing a new HOV/ETL structure between SR 167 and I-405; widening/replacing the I-405 bridge over SR 515 (Bridge Number 405/016); and constructing new retaining walls. This project will modify local roadways, including East Valley Road and S. 14th Street, related to the interchange improvements and I-405/SR167 widening; install sign bridges; install ITS and tolling; install/replace noise walls; construct storm water management facilities; and modify/replace existing stream crossing(s) at SR 167 and I-405 to improve fish passage. Current funding provides for preliminary design, environmental documentation, completion of necessary permits, and right of way acquisition. Additional funding is required to complete final design and construction. This memorandum is for reference Casey Kramer (Rev. Nov 2015) March 2015 Page 2 Figure 1 – Existing Culverts in the Project Vicinity Casey Kramer (Rev. Nov 2015) March 2015 Page 3 Fish Passage To comply with federal permanent injunction number C70-9213, dated March 29, 2013, Washington State Department of Transportation (WSDOT) is proposing to include with the I-405/SR 167 Interchange Direct Connector Project a fish passable structure at State Route 167 at Milepost (MP) 25.93 for Rolling Hills Creek. The existing Rolling Hills/Thunder Hills Creek crossing, a 3 foot by 4 foot box culvert, at SR 167 Mile Post 26.08 has been identified as a partial fish barrier, due to flow velocity, by Washington State Department of Fish and Wildlife (WDFW) and WSDOT Environmental Services Office (ESO) (WDFW No. 991202 – identified as Culvert C76 in Figure 1). Per the injunction, and in order of preference, fish passage should be achieved by the following design options: (a) avoiding the necessity for the roadway to cross the stream, (b) use of a full span bridge, or (c) use of the “stream simulation” methodology. WSDOT evaluated each potential design options as defined in the injunction. Avoidance of the stream crossing was determined to not be viable given the location of the highway and the need to maintain a critical transportation corridor. The next option, replacing the culvert with a bridge, was determined to be not practical due to clearance issues considering the highway profile over the crossing. The third option, using the “stream simulation” methodology, was determined to be the best alternative. The proposed project will replace the existing 4-foot wide by 3-foot high, 265 foot long concrete box culvert with a minimum 14.7-foot span, fish passable structure while providing a safe roadway for the traveling public. The proposed fish passable structure will be designed to meet the requirements of the federal injunction utilizing culvert design criteria stated in the injunction and developed by WDFW. The proposed SR 167 crossing location, which differs from the existing location, has been coordinated for compatibility with the City of Renton’s future options for providing fish passage to the west between SR 167 and Springbrook Creek. The proposed crossing is located on SR 167 south of I-405 in King County in the City of Renton, Washington. SR 167 runs south-north and spans Rolling Hills Creek. The creek generall y flows east to west and joins Springbrook Creek approximately 0.5 miles to the west of SR 167. This memorandum documents a preliminary engineering assessment of Culvert 76, and the surrounding area, to determine the basis for design. The basis of stream and fish passable structure design is drawn from site reconnaissance and field data collected during I-405 corridor planning, as well as the design phase of the current project. In addition to field observations, the preliminary design considers hydrological models provided by the City of Renton, hydraulic analysis, and streambed design. . Casey Kramer (Rev. Nov 2015) March 2015 Page 4 Site Reconnaissance As-Built Information The Rolling Hills Creek crossing under SR 167 at Mile Post 26.08 is presumed to have been constructed as part of the original SR 167 embankment grading contract prior to the first paving contract #0-7659 built in 1964. As-built plans are not available. The existing culvert has been field measured and determined to be a 3 foot by 4 foot concrete box culvert—sloping down from east to west at 1.75 percent. The downstream end of the box culvert connects into the City of Renton’s 60-inch diameter storm drain system. The City provided as-built drawings for this system which was constructed as part of L.I.D. 314 East Valley Road Street, Water and Sewer Improvements, dated 1971. The City’s system is located west of SR 167 and runs under East Valley Road and SW 19th Street. Floodplain Rolling Hills Creek and its associated wetland area at the east side of Culvert 76 have been identified as special flood hazard areas inundated by the 100-year flood. To the west, Springbrook Creek is identified as floodway area. Floodplain zones have been identified in the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRM) (See Attachment 1 Map 53033C0977F, Map 53033C0978F, and Map 53033C0979F). Floodplain zones related to the Green River and Springbrook watershed are identified as follows: • Northeast of SR 167/I-405 Interchange, adjacent to the Renton Village (Zone A, AE and AH), • North of Panther Creek between SW 27th Street and SW 16th Street, west of SR 167 (Zone AE and AH), • Springbrook Creek (Floodway Areas within Zone AE). The final design will assure that there is no rise in the floodplain and compensatory floodplain storage needs will be evaluated as required by Renton Municipal Code 4-3- 050 Critical Areas Regulations. Wetlands The Panther Creek Wetlands complex east of SR 167 is rated as Category II according to the Washington State Wetland Rating System for Western Washington, and a Category I based on the City of Renton Critical Areas Ordinance. Replacement of Culvert 76 with a larger structure has a high likelihood of permanently altering the hydrology of the wetlands. Hydrology is currently maintained by impoundment of runoff by SR 167 and a series of culverts that equalize water levels across the berms that are oriented perpendicular to the highway. The new stream channel alignment will drain a portion of the wetland. Areas adjacent to the channel may dry out over time and lose wetland Casey Kramer (Rev. Nov 2015) March 2015 Page 5 characteristics. The permanent loss of wetland area and functions will be mitigated off- site, utilizing credits from the approved Springbrook Mitigation Bank. This impact is considered unavoidable due to WSDOT’s requirements under the federal court injunction. Interdisciplinary Team On-Site Review An Interdisciplinary Team (IDT) conducted on-site reviews to assess existing culverts that cross SR 167 in the project area. Site visits occurred on the following dates: IDT visits: December 2004 to January 2005 Additional visits: July 2006 to January 2007 (Tukwila to Renton Improvements Project - environmental documentation); April 2014 (Project land surveys) September 2014 site visit with the Muckleshoot Indian Tribe and WDFW The information gathered through the IDT visits contributed to the field data in this report. Review and assessment of fish passable structures during these visits included analysis of the culvert and its condition, assessment of the waterways and streams, and assessment of the fishery associated with those streams. Hydrologists assessed the function of the culvert or the fish passable structure. Fisheries biologists assessed culverts and drains associated with streams, wetlands, or rivers that cross under the freeway infrastructure. Storm water and engineering design teams also contributed by providing physical data on the area, site specifications, and conceptual designs. The Rolling Hills Creek and Thunder Hills Creek combine as one channel that flows under I-405 on the east side of the SR 167 interchange. The stream is typical of heavily urbanized small stream systems of Lake Washington. These streams carry large sediment loads associated with the high percentages of impervious surfaces that drain un- attenuated into the streams. This leaves the stream flashy and heavily undercut in some locations. Stream bed gravels are sparse or absent and devoid of large woody debris. The highly urban characteristic of the basin results in higher than favorable stream temperatures. There are multiple public and private barriers upstream and downstream on this system with some sections thousands of feet long. Located within the City of Renton, the basin that is upstream of the I-405 crossing encompasses approximately 925 acres according to “East Side Green River Watershed Plan” information provided by the City of Renton. The area is a combination of single and multi-family residential and commercial developments. The basin drains under I-405 through Culvert 42 during low flows and also through Culvert 44 during higher flow conditions (Figures 2 and 3). Casey Kramer (Rev. Nov 2015) March 2015 Page 6 Figure 2: Rolling Hills Creek Crossing at I-405—Inlets to Culverts 42 (right) and 44 (left). Figure 3: Rolling Hills Creek Channel—Upstream of I-405 and Culverts 42 and 44. Casey Kramer (Rev. Nov 2015) March 2015 Page 7 Downstream of I-405, the existing Rolling Hills Creek channel daylights for approximately 430 feet prior to entering the existing Culvert 76 (Figures 4 and 5). The creek channel runs along the east side of SR 167 collecting flows from a relatively small area including the undeveloped wooded Talbot Hill slope and wetland areas. The creek is characterized as a narrow channel with the SR 167 roadway embankment on the west side and wetland area on the east. On the September 2014 site inspection with WDFW and the Muckleshoot Indian Tribe the observed bank full width was approximately 10 feet both upstream and downstream of I-405. Looking North at the Northern Section Looking North at the Southern Section Near the Northbound Ramp to I-405 Near the SR 167 (Culvert 76) Crossing Figure 4: Rolling Hills Creek Channel—Upstream of SR 167 and Culvert 76 Crossing. Casey Kramer (Rev. Nov 2015) March 2015 Page 8 Figure 5: Rolling Hills Creek Crossing at SR 167—Inlet to Culvert 76 Downstream of the existing box culvert (Culvert 76) under SR 167, the stream is conveyed in a 60-inch diameter City of Renton storm drain designated as Culvert 75 in Figure 1. The City’s storm drain system runs under East Valley Road and SW 19th Street for approximately 3,200 feet to the outlet into Springbrook Creek. Springbrook Creek conveys flows to the Black River Pump Station where flows are typically pumped into the Green River (“Conveyance” condition). The pumps are shut down during high flow conditions on the Green/Duwamish River. According to the King County “Black River Needs Assessment and Capital Improvements Plan, March 2015” the pump station includes an “Alaska Steeppass (Denil) fish ladder [which] allows adult fish to migrate upstream past the station, and an airlift system allows juvenile fish to migrate downstream. Apart from these mechanical fish passage systems, the pump station is a complete barrier to fish passage.” The pump station is listed as Site ID Casey Kramer (Rev. Nov 2015) March 2015 Page 9 09.0004 0.20 on the WDFW fish barrier list and is shown as not being a fish barrier. Site reconnaissance found the facility to be marginal by today’s standards. Hydrology Watershed The Rolling Hills Creek and Thunder Hills Creek watershed drains 925 acres (1.45 sq. mi.) (see Attachment 2). The maximum basin elevation is 400 feet and the mean basin elevation is approximately 250 feet (NAVD88). The majority of the drainage basin is medium to dense residential development with some commercial properties on the north side of I-405. Undeveloped portions of the basin are steep, but there is potential that the basin will become more developed in the future through redevelopment of the residential areas. To assure that the full range of hydrological conditions are understood, the design uses the City of Renton’s definition for both existing and future land use in the upstream basin: 32 percent and 50 percent of upstream basin impervious, respectively. Rolling Hills Creek Table 1 shows the calculated peak flows for Rolling Hills Creek at the proposed fish passable structure utilizing the City of Renton HSPF Model output. The following peak flow rates were developed by Northwest Hydraulics Company, 2011 and 2012. Table 1: Peak Flows for Rolling Hills Creek Based on Existing Hydrologic Models (in cubic feet per second) Mean Recurrence Interval (MRI) Flow Through C42/C442 Flow Through C761 Existing Land Cover Future Land Cover (f) Existing Land Cover Future Land Cover (f) 2-year 109.1 132.9 55.8 62.1 10-year 140.2 169.1 64.7 69.7 50-year 170.2 204.5 70.9 75.7 100-year 183.8 220.5 73.2 78.2 1. 2012 Panther Creek (Thunder Hills Mitigation Project) Hydraulic Report Append B - NHC Report 2. 2011 Renton Nickel Stage 2 & SR 515 IC Project, As-Built Hydraulic Report – Appendix A3.9.2 Flows out of the wetland are complicated by the hydraulic interaction between flow in Culvert 76 and two 36-inch diameter corrugated metal pipe (CMP) culverts that also drain the wetland through a waterline access berm to the south. There was some uncertainty about the HSPF model calibration of the flow split, so downstream flows (through C76) were verified using the U.S. Army Corps of Engineers’ HEC-RAS computer program, one-dimensional steady flow numerical model. HEC-RAS has a channel reach junction “optimization routine” which facilitated looking at the hydrologic Casey Kramer (Rev. Nov 2015) March 2015 Page 10 interaction between the culverts. Table 2 provides the calibrated values that will be used in the fish passable structure final design. Table 2: Corrected C76 Peak Flows (in cubic feet per second) Mean Recurrence Interval (MRI) Flow Through C76 Existing Land Cover Future Land Cover (f) 2-year 62.0 73.4 10-year 68.4 76.2 50-year 71.0 77.0 100-year 72.8 78.4 Source: WSDOT I-405 Corridor Program, Oct. 2014. Hydraulic Analysis Existing Condition Springbrook Creek Downstream of the C76 culvert crossing, Springbrook Creek conveys flows to the Black River Pump Station where flows are typically pumped into the Green River (“Conveyance” condition). The pumps are shut down during high flow conditions on the Green/Duwamish River, and Springbrook can be influenced by backwater (“Storage” condition) at its confluence with Rolling Hills Creek. The tailwater condition for this analysis has been based on the “East Side Green River Watershed Plan Technical Memorandum Supplement – Working Draft,” dated August 18, 2004. It published the following Table 3 data for water surface elevations (NAVD88). The table also includes “Existing” and “Future” (full build-out) land use conditions in the watershed that are considered in the analysis. Casey Kramer (Rev. Nov 2015) March 2015 Page 11 Table 3 - Springbrook Creek Water Surface Elevation at the Confluence of Rolling Hills Creek Condition Existing Land Cover Conditions Future Land Cover Conditions Conveyance Storage Conveyance Storage 2-yr Cur. Flow 11.7 - 12.7 10-yr Cur. Flow 13.8 - 14.2 25-yr Cur. Flow 14.41 14.4 14.9 15.0 50-yr Cur. Flow 14.6 14.8 15.1 17.4 100-yr Cur. Flow 15.4 17.4 15.4 17.4 Notes: 1. The 16.5 value in the reference document looks wrong based on the other numbers. The analysis used 14.4. 2. Elevations are provided in NAVD88 (in feet) Rolling Hills Creek The Rolling Hills Creek tributary was not available in earlier models, so a new model was developed using the U.S. Army Corps of Engineers’ HEC-RAS computer program, one-dimensional steady flow numerical model. There are three reaches in the model: • Downstream of Culvert 76 – includes the City of Renton storm drainage system in East Valley Road and SW 19th Street. • Culvert 76 – includes the WSDOT culvert from the City of Renton storm drainage system connection to the east side of SR 167. • Upstream of Culvert 76 – includes the wetland, stream, Culverts under I-405, and stream segment upstream of I-405. Casey Kramer (Rev. Nov 2015) March 2015 Page 12 Figure 6: Rolling Hills Creek Existing Model layout Downstream of Culvert 76: The final design will include evaluating the City of Renton storm drainage system flow and backwater changes. Note that the flows into this (C76) system (shown in Table 2) are significantly lower than the flow rate entering the wetland (through C42/C44) as shown in Table 1. The storm drainage system is a 60-inch concrete pipe trunkline that was constructed in the mid-1980s at 0.15 percent grade with frequent lateral connections from inlets along street gutters on both sides. The flowline elevation is one foot below the Culvert 76 flowline elevation at the connection. Culvert 76 The existing Rolling Hills/Thunder Hills Creek crossing, a 3 foot by 4 foot box culvert, at SR 167 Mile Post 26.08, has been identified as a partial fish barrier, due to flow velocity, by the Washington State Department of Fish and Wildlife (WDFW) and WSDOT Environmental Services Office (ESO) (WDFW No. 991202 – identified as Culvert C76 in Figure 1). The culvert was built as part of the initial fill for the SR 167 corridor. It existed prior to the 1967 paving project that built the roadway, but no as-built drawings have been found. The culvert gradient is fairly low at 1.75 percent based on recent survey data. The undersized culvert leads to high velocities during peak flow conditions. Casey Kramer (Rev. Nov 2015) March 2015 Page 13 Upstream of Culvert 76 The existing channel runs along the base of an SR 167 retaining wall that elevates the roadway above the wetland. The channel width is fairly uniform at 10 feet or less wide, with a retaining wall to the west and a 2 to 3 foot slope up to the wetland level to the east. The channel gradient is less than 0.2 percent. Prior modeling efforts noted that the water levels in the wetland rise enough during high flow events to overtop a waterline easement berm and spill into the Panther Creek wetland. Table 1 illustrates how the existing downstream pipe capacity influences attenuation within the wetland during design storm flows. The existing water surface profiles are depicted in Figure 7. Figure 7: Rolling Hills Creek Model Results for the Stream Channel from Springbrook Creek (left), through C76 (middle) and C42/C44 (right) Also upstream of Culvert 76, the wetland is located along the top of bank to the east and south of the Rolling Hills Creek channel. The wetland is a standing pool at elevation 17.0. Flows typically discharge groundwater seeps from the wetland to the channel near the inlet to Culvert 76. When the channel reaches flow elevations greater than 17.0 (approximately the 2-year design storm), the wetland serves as floodplain storage for the channel. It also serves as a second discharge route as pool levels rise, the wetland also drains south through the utility access berm located near SW 19th Street. HEC-RAS is a useful tool to evaluate the hydraulic characteristics of this split flow condition. Casey Kramer (Rev. Nov 2015) March 2015 Page 14 Proposed Condition The hydraulic analysis for the proposed condition has been broken into four sections to facilitate assessment of performance criteria set for the project. Downstream of Culvert 76: When the project increases the flow capacity under SR 167, the hydraulic head necessary to convey peak flow under SR 167 will decrease. With this decrease, the backwater effect and storage in the upstream wetland will decrease. The change in flow attenuation will potentially alter the flow rates and backwater condition in the City system. To address this, the design may include a flow restrictor at the connection to the City storm sewer system. The exact design criteria are being coordinated with City staff and will be set prior to issuing the Design-Build RFP. Fish Passable Structure: The proposed Culvert C76 replacement and Rolling Hills Creek channel extension will improve fish passage by: 1) Eliminating the partial fish barrier under the SR 167 highway, 2) Extending the length of channel within the northern section of the Panther Creek Wetland complex, and 3) Replaces the existing SR 167 culvert crossing with a new fish passable structure designed with stream simulation methodology. The new fish passable structure size was determined using the 2013 WDFW Water Crossing Guidelines. The bankfull width was calculated using a “Watershed Characteristics” method that utilizes a regression equation based on annual precipitation and basin area. This method is appropriate to estimate bankfull width where the basin is severely manipulated in areas such as the Project setting. Wch = 0.95 × WA0.45 × AAP 0.61 Equation 1 (WDFW Equation C.1) Where Wch is the width of the bankfull channel in feet; WA is the watershed area (square miles); and AAP is the average annual precipitation (inches). The watershed area (Attachment 2) is estimated to be 1.5 square miles in size. The average annual precipitation is estimated to be 38.6 inches. The calculated bankfull width using Equation 1 is 10.6 feet. This value is consistent with site reconnaissance measurements made on the natural stream section where the channel flows through the wetland on the east side of SR 167 approximately 100 feet south of the outlet from Culverts 42 and 44. The new fish passable structure will be constructed on a very flat gradient to match the channel section upstream and the future channel section downstream. Casey Kramer (Rev. Nov 2015) March 2015 Page 15 The WDFW Stream Simulation equation determines the fish passable structure width: WCulvert _ bed = 1.2 ∗Wch + 2 (in feet) Equation 2 (WDFW ,Equation3.2) Based on the 10.6 foot bankful width results from Equation 1 (above), the minimum opening width is 14.7 feet, based on Equation 2. Figure 8 illustrates one option where the 14.7 foot wide opening is provided by an elliptical arch pipe. This was used in the conceptual design analysis, but there are several fish passable structure options that are available to achieve the minimum width. Final selection of the type of fish passable structure will be determined by the Design- Builder contractor during final design based on other factors such as cost, speed of construction, and other factors that are not known now. The following discussions about conceptual design hydraulic models will be verified and performed as the design continues as needed to meet specific performance criteria set by WSDOT and the permits. Key elements of the performance criteria have been reviewed as part of the conceptual design (one feasible solution). Figure 8: Rolling Hills Creek Proposed Model for the Fish Passable Structure The proposed design will be required to match the modeled existing 100-year water surface elevation in the wetland. To accomplish this when the connection to the City storm sewer system is considered, the connection pipe size will create similar backwater condition and approximately maintain the existing attenuation by the wetland storage. Therefore, the connection design will protect the downstream system from flow increases. The design intent is for the fish passable structure to be forward compatible with future fish passage improvements downstream. Funding and timing for those future improvements are uncertain. Casey Kramer (Rev. Nov 2015) March 2015 Page 16 Figure 9: Rolling Hills Creek Model Layout for Proposed Condition Casey Kramer (Rev. Nov 2015) March 2015 Page 17 In addition to the connection to the SW 19th Street storm drainage system, the Project will reconstruct the two 36-inch culverts that connect to Panther Creek wetland to the south. The two culverts through the utility berm (to the south) assure that the hydrology is preserved in the wetland to the south of the new channel. Casey Kramer (Rev. Nov 2015) March 2015 Page 18 Figure 10: Rolling Hills Creek Model Channel Profile for Proposed Condition Casey Kramer (Rev. Nov 2015) March 2015 Page 19 The 100-year water surface elevation approximately matches the existing condition and there is no appreciable backwater as a result of the proposed structure, thereby meeting WAC 220-110-070 requirements (Figure 10). The channel slope through the culvert will match that of the new main channel upstream. This meets the stream simulation criteria described in the 2013 WDFW Water Crossing Guidelines and the requirements of the federal injunction. Stream Design The proposed Rolling Hills Creek channel through the proposed fish passable structure is designed to mimic a natural channel geometry. The proposed 0.27 percent sloped channel is preliminarily designed as a 5 foot bottom width and an 11 foot bankfull (2-year flow) width which then transitions into the existing slopes. The final design will verify the proposed channel design based on soils and geomorphic conditions specifically channel geometry and hydraulic characteristics. The proposed streambed gradation for the new channel will be determined during final design by the Design-Builder utilizing the methods described in the 2013 WDFW Water Crossing Guidelines. Recommendation Based on the site reconnaissance, hydrological and hydraulic analyses, WSDOT recommends proceeding with the design of a minimum 14.7 foot span fish passable structure to meet federal permanent injunction C70-9213. We will continue to work with the Design-Builder as the project proceeds through design. If you have any questions or need further assistance regarding the information included in this memorandum please feel free to contact Bill James at (425) 456-8638 or Alan Black at (425) 450-2515. Attachments: 1. Design-Build Contracting Performance Standards 2. FEMA flood maps 3. Basin Map – Exhibit A from WSDOT, I-405, Nickel Improvement Project hydrology study. 4. 25% Fish Crossing Plan, Profile, and Typical Section cc: Mike Barber, HQ Environmental Services Office Bijan Khaleghi, HQ Bridge Office Jim Cuthbertson, HQ Geotechnical Office HQ Hydraulics File Casey Kramer (Rev. Nov 2015) March 2015 Page 20 Attachment 1: Design-Build Contracting Performance Standards The proposed fish passable structure conceptual design will hold this Basis of Design document as the basis of the Project permits. As the project advances through the request for design-build proposals and award phases, some limited flexibility will remain until final design decisions are determined by the Design-Builder. Performance-based design requirements will guide the Design-Builder. Those requirements include the following: • The east end of the fish passable structure will transition as needed to the stream restoration section to the east. • The west end will be capped with a solid water tight wall at the WSDOT right-of- way line and a new storm drainage connection to the existing City of Renton drainage system under East Valley Road will be created. The details of the connection will be subject to WSDOT and City of Renton reviews during final design. • Construction staging will require temporary stream diversion during the downstream connection to East Valley Road. The requirements for that work will be established by an HPA. The existing culvert C76 crossing may be maintained during construction of the new SR 167 crossing so the type and duration of the temporary diversion will be significantly different than that required at the Thunder Hills Mitigation Fish Barrier Retrofit Project. The Design-Builder is required to prepare the design as part of the Environmental Compliance Plan. • The Design-Builder will provide final hydraulic design including assessment of downstream flows in the City storm sewer system; flood storage; sizing of stream bed gravel; and assessment of flow velocities and scour at the new crossing. • Contract performance criteria will be set up to follow specific mandatory standards including: o WDFW’s Water Crossing Design Guideline 2013 o Environmental commitments that result from the permitting effort. The current Mandatory Standards (in order of precedence) will include but not be limited to: • Special Provisions. • Amendments to the Standard Specifications. • Standard Specifications. • Washington Department of Fish and Wildlife Water Crossing Design Guidelines. Casey Kramer (Rev. Nov 2015) March 2015 Page 21 • NCHRP Report 568, Rip Rap Design Criteria, Recommended Specifications, and Quality Control. • WSDOT Highway Runoff Manual (M31-16). • WSDOT Hydraulics Manual (M23-03). • HEC-18, Evaluating Scour at Bridges; • EM 1110-2-1601 U. S. Army Corps of Engineers, Hydraulic Design of Flood Control Channels; and • HEC-11, Design of Riprap Revetment; • WSDOT Design Manual (M22-01) • US Forestry Service Stream Simulation Manual • HDS 5, Hydraulic Design of Culverts; • WSDOT Maintenance Manual (M51-01). • WSDOT Plans Preparation Manual (M22-31). • WSDOT Construction Manual (M41-01). • WSDOT Materials Manual (M46-01). • Standard Plans. • WSDOT Qualified Products List (QPL) (http://www.wsdot.wa.gov/Business/MaterialsLab/QPL.htm). • HEC-20 Stream Stability at Highway Structures; • WSDOT Guidance on Wildlife Habitat Structures in Wetland Mitigation Habitat Restoration Sites. • Washington State Aquatic Habitat Guidelines Program, Integrated Stream Guidelines. • Washington Department of Fish and Wildlife Aquatic Habitat Guidelines, Stream Habitat Restoration Guidelines. • National Marine Fisheries Service, Southwest Region, Fish Screening Criteria for Anadromous Salmonids. • National Marine Fisheries Service, Anadromous Salmonid Passage Facility Design. !. !. !. !. !. !. !. !.SR 167Lind Ave SWI -4 0 5 Fw y East Valley RdSW 43rd St SW 16th St SW 27th StOakesdale Ave SWSW 41st St SW 34th St S W G ra d y W a y SW 19th St SW 23rd St SW 39th St S W 1 2 t h S t E Valley HwyS 43rd StI-405 RampSW 21st St Oakesdale Ave SWI -4 0 5 Fw y SR 167Thunder Hills Panther Creek WetlandUpper Rolling HillsRenton Village Unnamed TribSW 23rd St Trib SW 34th St Trib Panther Ck Wtld Outlet N Panther Ck Wtld Outlet S Panther Ck Wtld Outlet Springbrook Creek D/S of SW 23rd St 1300000 1300000160000 160000170000170000WSDOT I-405 Nickel Improvement Projects Hydrologic Output Locations Part 3 Support the Basin Level Flow Control and Stream Restoration Concepts northwest hydraulic consultants project no. 21352DRAFTLegendWA Reference Map coord. syst.: WA State Plane S horz. datum: NAD 83 horz. units: feet Exhibit A ABC, C:\path\to\file\filename.mxd®0 10.5 Miles !.Hydrologic Output Locations Streets HSPF Sub Basins Springbrook Ck and Tribs 2.40 in WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘B’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘B’ Rolling Hills Creek Plans (Plan, Profile, and Details) See Submittal Copy WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘C’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘C’ Hydrology WSDOT Eastside Corridor Program RFP Appendix H3 Preliminary Hydraulic Design Analysis for Rolling Hills Creek Realignment January 2015 I -405/ SR167 Interchange Direct Connector Project Page 1 1. Introduction The Washington Department of Transportation (WSDOT) I-405/ SR167 Interchange Direct Connector Project (Project) site is located on I-405 in the vicinity of the SR 167 and SR 515 interchanges within the City of Renton, Washington (City). The Project is part of the overall I-405 Tukwila to Renton Improvement Project that includes consideration of channel realignment and restoration the Rolling Hills Creek on the east side of SR 167 within the project limits. The Project will construct a new direct connector ramp for a high occupancy vehicle (HOV)/express toll lane (ETL) in each direction between SR 167 south leg HOT lanes and I-405 north leg HOV lanes. Included is reconstructing sections of I-405 and SR 167 to open up the medians to make room for the new direct connector ramp; constructing a new HOV/ETL structure between SR 167 and I-405; widening/replacing the I-405 bridge over SR 515 (Bridge Number 405/016); and constructing new retaining walls. This project will modify local roadways, including East Valley Road and S. 14th Street, related to the interchange improvements and I-405/SR167 widening; install sign bridges; install ITS and tolling; install/replace noise walls; construct storm water management facilities; and modify/replace existing stream crossing at SR 167 to improve fish passage. Current funding provides for preliminary design, environmental documentation, completion of necessary permits, and right of way acquisition. Additional funding is required to complete final design and construction. The SR 167 culvert crossing is the subject of the “Preliminary Basis of Fish Mitigation Design” memorandum (RFP Appendix H2). That memorandum discusses the proposed location change for the SR 167 crossing. The roadway widening associated with the Project fills the existing Lower Rolling Hills Creek channel, so the Project looks beyond the culvert crossing to include construction of a new 1,400 foot long channel from WSDOT’s Culverts 42 and 44 to the new Culvert 76. This document discusses the hydraulic analysis approach used in developing preliminary engineering for the new channel, wetland, and flood condition elements. The primary goals of this effort are to: • Establish preliminary design standards for the Project (including coordination with the agencies), • Create a preliminary design that meets the Project standards • Assess the existing condition during monthly average flow conditions as well as the design storm events (2-, 10-, 25-, 50-, and 100-year design storms), • Verify that the proposed facilities will not increase the 100-year FEMA regulated floodplain elevations. Analysis will be based on the current FEMA floodplain 100-year water surface elevations as presented on the Flood Insurance Rate Maps and the Flood Insurance Studies. This document is a reference for the Design-Build contractor and summarizes the hydraulics models, assumptions, and sources used. The design-build contractor is required to verify these design elements and develop the final design. The recommendations included in this document are therefore subject to change as the design continues. This document provide for reference I -405/ SR167 Interchange Direct Connector Project Page 2 Figure 1 – Existing Culverts in the Project Vicinity Figure 1 provides an illustration of the streams and culverts in the Project vicinity. The study begins in the open channel at the downstream end of Culvert 47. Culvert 42 and 44 will remain in their existing condition with the Project and Culvert 76 will move south to align with the westerly flowing section of Culvert 75. The channel and wetland storage between Culvert 42/44 and 76 are a key element of this study. Culvert 75 represents the City of Renton’s storm sewer system in East Valley Road and SW 19th Street and the connection to Springbrook Creek will remain at the end of the Project. . I -405/ SR167 Interchange Direct Connector Project Page 3 2. Hydraulic Analysis Approach: The City’s Watershed Study effort established the downstream condition in Springbrook Creek. The water surface elevation for each of the design storm events were provided directly. To assess the lower flow conditions that influence the wetland function, the Project developed monthly average conditions in Springbrook creek. This was done using the City’s HSPF and HEC-RAS model information as follows: • Monthly “Mean” flow rate were calculated using the City’s HSPF models. This provides the monthly average flow rates for Springbrook Creek and Rolling Hills Creek. • The water surface elevations reach were established by applying these flow rates to the City’s Springbrook Creek channel hydraulics model. 2.1. Basis of the Existing Condition Models The effort to assess Lower Rolling Hills Creek was developed from the following key references: Table 1 – References for HEC-RAS Model input Reference Provides City Green River Watershed Study1 Technical Memorandum Basis for 2-, 10-, 25-, 50-, and 100-year design storm event flow rates throughout the channel network. HSPF models developed by NHC for WSDOT during Panther Creek studies in 20052 Basis for statistical analysis by WSDOT to establish monthly average flow rates throughout the channel network. City Green River Watershed Study1 HEC- RAS ground section model of Springbrook Creek Basis for WSDOT Springbrook Creek model to establish monthly average tailwater condition for the Lower Rolling Hills Creek hydraulic model. City as-built drawings3 and WSDOT survey data4 Basis for hydraulic models Sources: 1. City of Renton “East Side Green River Watershed Plan Technical Memorandum Supplement – Final”, dated February 2007: Includes two basin scenarios: “Current Land Development,” and “Future (full build-out) Land Development.” 2. May 19, 2005 memorandum from Northwest Hydraulics Consultants (NHC). Specifically, Part III of South Renton Projects scenario with Panther Creek “south” diversion (through the Panther Creek wetland) is considered the existing physical hydraulic condition present in 2014 3. City as-builts for L.I.D. 314 Street, Water, Sewer, & Drainage Improvements for East Valley Road and SW 19th Street (R-1999) 4. WSDOT surveys and site visits in 2014. The hydrology (flow rate) model efforts were based on the work associated with a May 19, 2005 memorandum from Northwest Hydraulics Consultants (nhc). Specifically, Part III of South Renton Projects scenario with Panther Creek “south” diversion (through the Panther Creek wetland) which is considered the existing physical hydraulic condition present in 2014. I -405/ SR167 Interchange Direct Connector Project Page 4 Two basin definitions were evaluated: • Current (2001) Land Cover Conditions in the Basin (Model “SPRp3dC”) • Future (full build-out) Land Cover Conditions in the Basin (Model “SPRp3dF”) The original HSPF output (WDM) file did not provide flow data for all of the Reaches that were needed for this effort. The additional flow data was developed by running HSPF using each of NHC’s original UCI files to populate the WDM file with flows. The flow data was then extracted for statistical analyses using Basins v4.1 software. Four Reaches (see Figure 2 for locations) were evaluated: • Reach 103: Rolling Hills Creek flows into the North End of the Wetland • Reach 102-1: Rolling Hills Creek flows through Culvert 76 • Reach 11: Rolling Hills Creek flows through SW 19th Street system to discharge at Springbrook Creek • Reach 7: Springbrook Creek flows downstream of SW 19th Street/Rolling Hills Creek tributary An additional Reach is included to address the overflow into the Panther Creek wetland to the south during higher storm events: • Reach 102-2: Rolling Hills Creek overflow over the (SW 19th Street) berm The following results were for the Lower Rolling Hills Creek tributary: • Monthly average flow rates for the full period of rainfall record in HSPF, 1950 to 2001 (input into the spreadsheet for Current and Future Land Cover Conditions) • 2, 10, 25, 50, and 100-year design peak flow rates for five reaches (R103 to R7) illustrated in Figure 2. Summary tables (see Table 2 and Table 3) were developed to show the statistical flow rates from the monthly runoff predicted by each model. I -405/ SR167 Interchange Direct Connector Project Page 5 Figure 2 –Model Reaches as they relate to the Project Vicinity (i.e. R11 = Reach 11) 2.2. Springbrook Creek Hydraulics The City’s 1997 HEC-RAS model ground data was used to establish the flow conditions at the discharge of the SW 19th Street storm sewer system. In this model, Reach 7 represents the river section between SW 19th Street and SW 16th Street. Reach 5 represents the section under I-405 between SW 16th Street and Grady Way, and Reach 1 represents the downstream section between Grady Way and the Black River Pump Station (see Figure 3). Figure 3 – Springbrook Creek channel profile showing monthly average flow conditions. I -405/ SR167 Interchange Direct Connector Project Page 6 The Springbrook Creek profile (see Figure 3), generated using this HEC-RAS model, illustrates that the downstream features influence the tail water in the SW 19th Street Reach (R11). Based on the downstream flow conditions, the tailwater condition is influenced by a rise in the channel bottom within Reach 1. Note that the correlation to the HSPF Model Reaches and the point of interest at SW 19th Street are included in the provided profile. Given the channel profile, monthly average flow rates were estimated for Reaches 1 and 5. This adjustment used a percentage-based calculation based on slightly higher flows show downstream in the City’s flood study ("ESGRWP Supplement", dated February 2007). Since the downstream increases do not have a significant impact on Rolling Hills Creek tailwater condition, so there was no need to refine this approximate method. The following tables provide a summary of the elevations that were applied as downstream tailwater conditions in the Rolling Hills Creek model. Table 2 - HEC-RAS Model input for mean flow calculation for Current conveyance condition – with current land use Model Station (Springbrook Creek Reach) Reach Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 4838 1 31.2 69.9 79.1 80.4 66.5 48.6 29.3 15.6 14.1 8.6 10.3 14.6 5773 5 28.0 62.7 71.0 72.2 59.7 43.6 26.3 14.0 12.6 7.7 9.3 13.1 6958 7 27.9 62.4 70.7 71.8 59.4 43.4 26.1 14.0 12.6 7.7 9.2 13.0 Note: The model station represents the number of feet of the Black River pump station measured along the centerline of Springbrook Creek. The Model stations also represent the upstream limit associated with the Reaches that are illustrated in Figure 3. Table 3 - HEC-RAS Model input for mean flow calculation for Current conveyance condition – with future land use Model Station (Springbrook Creek Reach) Reach Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 4838 1 37.0 82.4 90.2 89.7 72.8 52.5 31.1 16.2 14.8 8.4 11.0 16.4 5773 5 32.4 72.1 78.9 78.4 63.6 45.9 27.2 14.1 13.0 7.4 9.6 14.3 6958 7 32.1 71.4 78.1 77.7 63.0 45.5 27.0 14.0 12.8 7.3 9.5 14.2 Note: The shaded values are the actual statistical output from the HSPF model. These values were adjusted to match the values used in the HEC-RAS model for the current land use condition (assuming that the follow rates should be similar or slightly higher in reality). I -405/ SR167 Interchange Direct Connector Project Page 7 The Black River Pump Station operation could have an influence on the tailwater condition for Rolling Hills Creek. As shown in Figure 3, the pump station fore bay was assumed to be at elevation 1.00 (NGVD29) which is below the level of influence. The pump station is rarely shut off due to emergency flood stage condition in the Green River. The model assumption is that the monthly flow condition will not be influenced by the pump station. This “Conveyance” condition is the primary focus of the study. The City’s flood modeling included a “Storage” condition to represent the highest likely flood stage when the pumps are turned off. Those “Storage” values are included in Table 4 for referenced. Note that the Springbrook HEC-RAS model was originally developed referencing NGVD 1929 vertical datum. The City’s topographic mapping (1999) is in NAVD 1988 vertical datum. Because extensive effort would be required to change the datum in the original FEQ model, the City of Renton decided to continue the Springbrook Creek hydraulic modeling in NGVD 1929 and use a datum conversion to present results as well as prepare the concurrent floodplain mapping results. To convert elevations to NAVD 1988 vertical (Project) datum, 3.58 feet was added to establish tail water conditions for the Rolling Hills Creek HEC-RAS model which is in the NAVD 1988 Project datum. I -405/ SR167 Interchange Direct Connector Project Page 8 Table 4 provides a summary of the tailwater conditions that were developed by these flow rates in Table 2 and Table 3 and by other sources as noted. Table 4 - Springbrook Creek Water Surface Elevation at the Confluence of Rolling Hills Creek Condition Existing Land Cover Conditions Future Land Cover Conditions Conveyance Storage3 Conveyance Storage3 October1 6.99 7.08 November1 7.64 7.81 December1 7.79 7.92 January1 7.81 7.91 February1 7.59 7.66 March1 7.3 7.34 April1 6.95 6.98 May1 6.66 6.67 June1 6.63 6.64 July1 6.50 6.49 August1 6.54 6.56 September1 6.64 6.68 2-yr Cur. Flow2 11.7 - 13.0 10-yr Cur. Flow2 13.8 - 14.2 25-yr Cur. Flow2 14.44 14.4 14.9 14.94 50-yr Cur. Flow2 14.6 14.8 15.0 15.3 100-yr Cur. Flow2 14.8 16.8 15.3 17.4 Notes 1. Mean Monthly Flow rate based on WSDOT model/estimate, May 2014. 2. “East Side Green River Watershed Plan Technical Memorandum Supplement – Final” dated February, 2007 values are based on FEQ models and were provided by the City of Renton. 3. Storage condition represents the Green River high-flow condition when the Black River pump station is turned off: Springbrook Creek becomes the basin “storage” behind the pump station. 4. The table show the condition used (equals the Conveyance elevation) rather that the City’s values that seemed off (implying an error) in the 2007 report. 5. Elevations are provided in NAVD88 datum (in feet) I -405/ SR167 Interchange Direct Connector Project Page 9 2.3. Lower Rolling Hills Creek Hydraulics There were no pre-existing hydraulic models for this reach. The new model components are as follows: • 50 foot, 60-inch diameter, CMP culvert passing through the Springbrook Creek right bank. • Open channel section between the culvert and Raymond Avenue. • 2960 foot long 60-inch storm sewer trunkline under SW 19th Street from Raymond Avenue to East Valley Road then under East Valley Road north to WSDOT Culvert 76. As-built plans were used to create a multi-culvert model with short rectangular channel sections to represent each manhole. • Culvert 76: 245 foot 3 foot by 4 foot box culvert connecting the City storm sewer trunkline under SR 167 east to the Rolling Hills Creek channel and wetland. • Open channel through an existing wetland complex along the eastern edge of SR 167 north to WSDOT culverts 42 and 44. • Culverts 42 and 44 under I-405 • Open channel continuing east along the northern edge of I-405 Given the complexity of the channel and pipe systems, there has been some discussion about the best approach to evaluate hydraulics along the tributary. WSDOT selected HEC-RAS to model the full length of Lower Rolling Hills Creek. This allows preliminary hydraulic design evaluation using one model. 2.3.1. Existing Condition Model Definition Each component of the stream was approximated as follows: The 50 foot culvert passing through the Springbrook Creek right bank. This crossing is not on the City mapping but was field verified in 2014. The Rolling Hills Creek is separated from Springbrook Creek by a wide earthen berm that is as high as the channel banks. The culvert is 60 inch diameter corrugated metal with a projecting end into the Rolling Hills Creek channel. The culvert was observed to be clean and free flowing in July’s low-flow conditions (not influenced by the water depth in Springbrook Creek. Without survey, the pipe slope was estimated based on field observation and what we know about ground elevations on each side of this culvert. I -405/ SR167 Interchange Direct Connector Project Page 10 Culvert through Berm along Springbrook Creek (upstream end) Lower Rolling Hills Creek Channel upstream of Springbrook Creek Culvert (looking east) Open channel section between the culvert and Raymond Avenue. This section was visited in May 2014. The channel is fairly uniform with 6 foot bottom, 2:1 left bank and 3:1 right bank. The channel depth is about 10 feet. No land survey was conducted, so this section was estimated by a simple trapezoidal section based on field measurements. The models confirm that flow conditions in this section do not significantly influence water levels in the project area, so a more detailed survey is not warranted. The City of Renton 60-inch storm sewer trunkline under SW 19th Street from Lind Avenue to East Valley Road then under East Valley Road north to WSDOT Culvert 76 was modeled based on as-built drawings that were provided by the City. The WSDOT 3 foot by 4 foot box culvert (Culvert 76) connecting the City storm sewer trunkline under SR 167 east to the Rolling Hills Creek channel and wetland was modeled based on as-built drawings that were provided by the City (for the west end) and survey data (on the east end). I -405/ SR167 Interchange Direct Connector Project Page 11 Rolling Hills Creek Crossing, Culvert 76 (upstream end) Rolling Hills Creek near the Northbound SR 167 Ramp to Northbound I-405 (looking north) The Open channel along the eastern edge of SR 167 north to WSDOT culverts 42 and 44; Culverts 42 and 44 under I-405; and open channel continuing east along the northern edge of I-405 were modeled based on detailed land surveys conducted in May 2014. The channel alignment and cross section locations were initially established in MicroStation. The Hydrology and Hydraulics Application Add-In was used to create a GIS format Geometry Data for HEC-RAS. The resulting model is in the project vertical and horizontal datum, NAVD88 datum (in feet), to facilitate direct comparison and updates as the design continues. Numerous culvert models were included to represent each of the pipe segments. The first culvert was defined to address the City pipe at Springbrook Creek. Nine additional culverts were defined to represent each pipe segment under the local streets, SW 19th Street and East Valley Road. Each manhole location was modeled as a short open channel section to approximate the culvert to pipe and culvert to pipe connections within HEC-RAS. The SR 167 cross culvert (Culvert 76) and the I-405 cross culverts (Culvert 42 and 44) were also included. The model definition of Culvert 42/44 has a dual culvert with the applicable shape for each. HEC-RAS considered the longer Culvert 42 length an error, so both culverts use the length of Culvert 44. Figure 4 illustrates the HEC-RAS model layout. I -405/ SR167 Interchange Direct Connector Project Page 12 Figure 4 - HEC-RAS Model Generated Layout of the Lower Rolling Hills Reach A WSPG hydraulic model was created to simulate the existing Culvert 76 storm drain system, from the Raymond Avenue outfall to the upstream side of SR 167. WSPG was selected since the program was specifically developed for closed conduit storm drain systems. The WSPG and initial HEC-RAS existing conditions future land use model results were compared to establish HEC-RAS entrance and exit culvert loss coefficients for the storm drain system. Culvert 76 HEC- RAS culvert entrance loss coefficients were all set to 0.2 and culvert exit loss coefficients were all set to 0.5. These coefficients better represent the expansion and contraction losses associated with storm drain man holes and created good agreement between the HEC-RAS and WSPG models. Figure 5 illustrates a water surface profile comparison between the HEC-RAS and WSPG model results. Figure 5 – Comparison of WSPG Model and HEC-RAS Model Water Surface Results after Calibration 0 5 10 15 20 25 0 500 1000 1500 2000 2500 3000 3500 4000WSE (ft NAVD) HEC-RAS Station WSPG HEC-RAS Raymond Avenue Outfall Culvert 76 Head I -405/ SR167 Interchange Direct Connector Project Page 13 The channel model Manning’s roughness coefficient values were input based on field observations in May 2014. Given the current sediment levels in Culvert 44, the model uses the option for defining different Manning’s roughness coefficient values for the top (corrugated metal) and bottom (smooth sediment). Hydrology input came from the same HSPF model effort that was described above for Reach 7 (Springbrook Creek). Table 5, Table 6, and Table 7. Table 5 – Rolling Hills Creek HEC-RAS Model input for mean flow calculation for current conveyance condition – with current land use Model Station (Rolling Hills Creek Reach) Reach Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 5580 103 0.49 0.99 0.95 0.98 0.72 0.51 0.32 0.18 0.18 0.09 0.14 0.19 3736 102-1 1.64 4.12 4.72 4.81 3.92 2.78 1.61 0.79 0.70 0.43 0.53 0.73 2751 11 1.81 4.48 5.09 5.19 4.23 3.01 1.76 0.86 0.77 0.46 0.58 0.80 Note: 1. Model Station 5580 is at the upstream limit of the Lower Rolling Hills Creek Model. 2. Model Station 3736 is located at the upstream end of WSDOT’s Culvert 76 under SR 167. 3. Model Station 2751 is located at the City storm sewer system connection between East Valley Road and SW 19th Street. Table 6 - Rolling Hills Creek HEC-RAS Model input for mean flow calculation for Current conveyance condition – with future land use Model Station (Rolling Hills Creek Reach) Reach Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep 5580 103 0.54 1.09 1.07 1.03 0.79 0.56 0.34 0.18 0.17 0.09 0.14 0.23 3736 102-1 2.13 4.97 5.34 5.29 4.21 2.97 1.72 0.84 0.77 0.42 0.60 0.91 2751 11 2.34 5.40 5.77 5.71 4.55 3.22 1.87 0.92 0.84 0.46 0.65 0.99 Table 7 - Rolling Hills Creek HEC-RAS Model input for Design Storm Events Model Station (Rolling Hills Creek Reach) Reach Current Land Use Future Land Use 2- Year 10- Year 25- Year 50- Year 100- Year 2- Year 10- Year 25- Year 50- Year 100- Year 5580 103 53.7 74.0 83.7 90.7 97.6 63.9 84.6 93.5 99.7 105 3736 102-1 64.8 92.0 106 116 126 81.2 109 123 133 143 2751 11 80.2 108 119 127 135 98.3 117 123 126 129 Note: The shaded values are the actual statistical output from the HSPF model. These values were adjusted to match the trend for downstream increases seen in the Current Conditions model (assuming that the follow rates should be similar in reality). I -405/ SR167 Interchange Direct Connector Project Page 14 2.3.2. Initial Existing Condition Model Results The following pages provide model result plots produced by HEC-RAS. The findings are as follows: The average monthly flows are very small and independent of the wetland hydrology most of the time (See Figure 6 and Figure 7). • During monthly average flows and up to the 2-year design storm event, the wetland pool is independent of the stream flows. • Head losses in the WSDOT Culvert 76 are significant and directly affect the water levels, storage, and attenuation of runoff events greater than the 2-year storm. Therefore, the design for the connection to the City storm sewer system will be critical to match downstream flows. • Storm event water surface depths in the wetland will reach levels that overflow the waterline utility access road berm (see photos on page 16) to the south (to the Panther Creek wetland) during the larger storm events in the Current Land Cover Condition model and all of the design storms in the Future Land Use condition as defined by the City of Renton HSPF model. • A more sophisticated split reach model is needed to address the overflow condition. A second model was developed to represent flows equal to and greater than the 2-year design storm event. See Section 2.3.3 for more detail. Figure 6 - Existing channel with Current Land Development Condition monthly average flows 0 1000 2000 3000 4000 5000 60005 10 15 20 25 30 35 RollingHillsFutureStorm_Flow Plan: Existing_Future_Low 10/30/2014 Main Channel Distance (ft)Elevation (ft)Legend WS Dec WS Jan WS Nov WS Feb WS M ar WS Oct WS Apr WS Sep WS M ay WS Jun WS Aug WS Jul Ground RollingHills Upper I-405/Culverts 42/44 SR-167/ Culvert-76 Springbrook Creek I -405/ SR167 Interchange Direct Connector Project Page 15 Figure 7 - Existing channel with Future Land Development Condition monthly average flows 2.3.3. Existing Condition Model Results for 2-Year and Larger Storm Events The simple single reach model that was used for the monthly average conditions was found to over-estimate water surface elevations in the larger design storm events. These larger storm events overtop the channel banks and interact with the adjacent wetland. This was addressed by creating a second model that looks at the effect of flows leaving the Rolling Hills Creek tributary through existing culverts through the waterline utility access road (berm) that crosses the wetland east of SR 167 in the vicinity of SW 19th Street. The second model facilitates evaluation of the flow slpit between Rolling Hills Creek flowing through the City drainage system to the west and the Panther Creek wetland to the south. Figure 8 provides an illustration of the additional sections that were added to reflect flows south though the wetland and to the Panther Creek wetland. SR-167/ Culvert-76 Springbrook Creek I-405/Culverts 42/44 I -405/ SR167 Interchange Direct Connector Project Page 16 Figure 8 - HEC-RAS Model Existing Conditions including the Wetland Reach that serves as an Overflow Route for Large Storm Events For this model, there are three reaches used to define the channel system: • The “Lower” Reach represents the City of Renton conveyance and Culvert 76. • The “Upper” Reach represents the Sections of Lower Rolling Hills Creek that are upstream of Culvert 76. • The “Wetland” Reach adds sections in the Rolling Hills Creek wetland that are south of Culvert 76 (the overflow path that is referenced in Section 2.3.2). NHC’s earlier work, associated with Culvert 72 fish passible structure design, had reported water levels in the downstream Panther Creek wetland, so the tailwater condition was readily available for this reach. WSDOT surveyed the wetland reach including detailed survey of the berm. Site visits also found a double 36-inch corrugated metal pipe crossing through the berm. I -405/ SR167 Interchange Direct Connector Project Page 17 Figure 9 - Waterline Utility Access Road Berm Photos: Above – View of access road looking east with the Rolling Hills Creek wetland to the left. Above right – View of the north end of the double culvert through the berm (looking west). Right - View of the south end of the double culvert through the berm (looking east). The flow split was initially estimated by running the (single reach model) with the access road modeled as a lateral structure. HSPF includes an “optimization” tool that looks at downstream capacities in the main channel and the lateral to determine the flow split. The resulting flow rates are provided in Table 8. I -405/ SR167 Interchange Direct Connector Project Page 18 Table 8 - Rolling Hills Creek HSPF Model Results for Existing Conditions Design Storm Events Model Station (Main Channel Distance) Reach Current Land Use Future Land Use 2- Year 10- Year 25- Year 50- Year 100- Year 2- Year 10- Year 25- Year 50- Year 100- Year 7155 (upper reach) = 5580 in Basic Model 103 53.7 74.0 83.7 90.7 97.6 63.9 84.6 93.5 99.7 105 4903 (wetland reach) 102-2 3.0 10.0 20.0 30.0 40.0 9.0 25.0 35.0 45.0 55.0 3736 (lower reach) 102-1 61.8 82.0 86.0 86.0 86.0 72.2 84.0 88.0 88.0 88.0 2751 (lower reach) 11 77.2 98.0 99.0 97.0 95.0 89.3 92.0 95.0 94.0 93.0 Note: The shaded values were developed by WSDOT to balance initial water surface elevations at the model reach junction. The total flow in the “Wetland” plus “Lower” reaches is still based on the value from HSPF described above. Results from Table 8 were used as a starting point for HEC-RAS modeling. HSPF flow rates were input into HEC-RAS and the flow optimization tool was used at the reach junction to balance flows between the upper reach, lower reach, and wetland assuming a consistent water surface elevation. Additional 19th Street inflows at HEC-RAS model station 2751 were assumed to be identical to the HSPF model results shown in Table 8. For example, HSPF computed an increase in 19th Street storm drain 100-year flows of approximately 9 cfs. This 9 cfs inflow was maintained for HEC-RAS modeling. Existing conditions HEC-RAS model flow rates are shown in Table 9. Table 9 - Rolling Hills Creek HEC-RAS Model Results for Existing Conditions Design Storm Events Model Station (Main Channel Distance) Reach Current Land Use Future Land Use 2- Year 10- Year 25- Year 50- Year 100- Year 2- Year 10- Year 25- Year 50- Year 100- Year 7155 (upper reach) = 5580 in Basic Model 103 53.7 74.0 83.7 90.7 97.6 63.9 84.6 93.5 99.7 105 4903 (wetland reach) 102-2 3.0 23.7 36.8 45 53.2 7.6 32.8 47.3 56 64.6 3736 (lower reach) 102-1 62 68.4 69.2 71 72.8 73.4 76.2 75.7 77 78.4 2751 (lower reach) 11 77 84.4 82.2 82 81.8 90.4 84.2 82.7 83 83.4 Note: The shaded values were developed using the HEC-RAS model junction optimization and are representative of the hydraulic controls in the system. The resulting HEC-RAS model output (Figure 10 for Current Land Use, and Figure 11 for Future Land Use) is considered to be representative of design storm conditions with the existing flow patterns and resulting water surfaces in Rolling Hills Creek. This model will facilitate evaluation of culvert and stream improvements proposed by the Project. I -405/ SR167 Interchange Direct Connector Project Page 19 Figure 10 - Existing channel with Current Land Development Condition - Design Storm Flows Figure 11 - Existing channel with Future Land Development Condition - Design Storm Flows 0 1000 2000 3000 4000 5000 60005 10 15 20 25 30 35 RollingHillsFutureStorm_Flow Plan: Existing_Current 10/29/2014 Main Channel Distance (ft)Elevation (ft)Legend WS 100-Year WS 50-Year WS 25-Year WS 10-Year WS 2-Year Ground RollingHills Lower RollingHills Upper 0 1000 2000 3000 4000 5000 60005 10 15 20 25 30 35 RollingHillsFutureStorm_Flow Plan: Existing_Future 10/29/2014 Main Channel Distance (ft)Elevation (ft)Legend WS 100-Year WS 50-Year WS 25-Year WS 10-Year WS 2-Year Ground RollingHills Lower RollingHills Upper I-405/ Culverts 42/44 SR-167/ Culvert-76 Springbrook Creek Springbrook Creek SR-167/ Culvert-76 I-405/ Culverts 42/44 I -405/ SR167 Interchange Direct Connector Project Page 20 2.3.4. Proposed Conditions Model Definition A proposed conditions model was created based on preliminary grading plans and culvert design. The existing conditions HEC-RAS hydraulic model geometry was revised to reflect the proposed conditions. All modeling assumptions and approaches previously discussed in Section 2.3.1 of this report were maintained for the proposed conditions model. New cross sections were cut from a preliminary grading surface for the model reach between the proposed Culvert 76 and I-405. Cross sectional geometry was prepared using ArcGIS Geo- RAS. The relocation of Culvert 76 required the proposed HEC-RAS model to lengthen the upper reach and reduce the length of the wetland reach. A similar approach was used to connect all three of the proposed HEC-RAS reaches. Figure 12 illustrates the plan view geometry of the proposed conditions HEC-RAS model. Figure 12 - HEC-RAS Model Proposed Conditions including the Wetland Reach that serves as an Overflow Route for Large Storm Events For the proposed condition model, the wetland reach is reduced to represent the shorter path through the proposed utility berm and two 36-inch culverts. The proposed grading for the utility berm places it next to the channel. The culverts would be replaced to serve as an equalizer between the Rolling Hills Creek floodplain and the Panther Creek wetland to the south. The culvert invert elevations will be set to maintain existing summer season pool elevations to the south. The proposed fish passage culvert was modeled in HEC-RAS as a pipe arch with a filled in bottom. Figure 13 presents a view of the upstream side of the pipe arch as modeled in HEC-RAS. I -405/ SR167 Interchange Direct Connector Project Page 21 Figure 13 – Upstream Face Proposed Fish Passage Culvert 76 A number of model iterations were completed to identify temporary connection to the City drainage system that would function as a hydraulic control between the new WSDOT fish passible structure and the existing downstream storm drain system. The main intent of the connecting pipe is to maintain the flow distribution between Culvert 76 and the downstream wetland. Based on the preliminary modeling, a 42-inch diameter CMP with a 0.3-ft deep grouted bottom was identified as an optimum design to maintain hydraulic controls and wetland hydrology. Figure 14 illustrates the upstream face of the 42-inch CMP as modeled in HEC-RAS. Figure 14 – Upstream Face Proposed Connection to the City Storm Drainage System HEC-RAS flow optimization was used at the junction of the upper reach, lower reach, and wetland reach assuming consistent water surface elevations. Downstream of Culvert 76, the SW 19th Street storm drain flows were modeled to be identical to existing conditions for all of the design storm events (per Table 5, Table 6, and Table 7). Table 10 presents a summary comparison of the existing and proposed conditions for the current hydrology and Table 11 presents a summary comparison of the existing and proposed conditions for the future hydrology. 0 20 40 60 8010 12 14 16 18 20 22 RS=2720 Upstream (Culvert) Elevation (ft) I -405/ SR167 Interchange Direct Connector Project Page 22 Table 10 - Rolling Hills Creek HEC-RAS Model Results for Runoff based on Current Land Use Existing Proposed Hydrologic Recurrence Interval Upstream of Culvert and Wetland (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Discharge (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Discharge (cfs) 2-Year 65 62.0 3.0 65.1 0.0 10-Year 92 68.4 23.7 68.5 23.5 25-Year 106 69.2 36.8 69.3 36.7 50-Year 116 71.0 45.0 71.0 45.0 100-Year 126 72.8 53.2 73.0 53.0 Table 11 - Rolling Hills Creek HEC-RAS Model Results for Runoff based on Future Land Use Existing Proposed Hydrologic Recurrence Interval Upstream of Culvert and Wetland (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Discharge (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Discharge (cfs) 2-Year 81 73.4 7.6 77.0 4.0 10-Year 109 76.2 32.8 76.3 32.7 25-Year 123 75.7 47.3 75.8 47.2 50-Year 133 77.0 56.0 77.0 56.0 100-Year 143 78.4 64.6 78.5 64.6 These summary tables illustrate that the proposed Culvert 76 facilities match existing flows for all hydrologic recurrence intervals except the 2-year. The 2-year proposed discharges are all within 5 percent of the existing discharges and would not result in a perceivable change in conveyance function in the storm drainage system. 2.3.5. Proposed Condition Model Results for 2-Year and Larger Storm Events HEC-RAS hydraulic models were completed for both the current hydrology conditions and the proposed hydrology conditions as defined in Table 10 and Table 11. HEC-RAS profile outputs for the current hydrology conditions are presented in Figure 15 and HEC-RAS profile outputs for the future hydrology conditions are presented in Figure 16. I -405/ SR167 Interchange Direct Connector Project Page 23 Figure 15 – Proposed channel with Current Land Development Condition Figure 16 – Proposed channel with Future Land Development Condition 0 1000 2000 3000 4000 5000 60005 10 15 20 25 30 35 RollingHillsFutureStorm_Flow Plan: Proposed_Current 10/29/2014 Main Channel Distance (ft)Elevation (ft)Legend WS 100-Year WS 50-Year WS 25-Year WS 10-Year WS 2-Year Ground RollingHills Lower RollingHills Upper 0 1000 2000 3000 4000 5000 60005 10 15 20 25 30 35 RollingHillsFutureStorm_Flow Plan: Proposed_Future 10/29/2014 Main Channel Distance (ft)Elevation (ft)Legend WS 100-Year WS 50-Year WS 25-Year WS 10-Year WS 2-Year Ground RollingHills Lower RollingHills Upper Springbrook Creek Springbrook Creek SR-167/ Culvert-76 SR-167/ Culvert-76 I-405/ Culverts 42/44 I-405/ Culverts 42/44 I -405/ SR167 Interchange Direct Connector Project Page 24 A comparison of existing and proposed condition water surface elevations was completed for both current and future hydrology conditions to better identify impacts from proposed improvements. Table 12 presents a summary of the water surface elevations for current hydrology conditions and Table 13 presents a summary of the water surface elevations for future hydrology conditions. Values are shaded green if they are less than the respective value, red if they are greater than the respective value, or shaded brown if they are equal to the respective value. Table 12 – HEC-RAS Existing and Proposed Conditions Water Surface Comparison Current Conditions 2-Year 10-Year 25-Year 50-Year 100-Year Location Exist Prop Exist Prop Exist Prop Exist Prop Exist Prop Upstream of Culvert 42 and Culvert 44 20.34 20.34 20.76 20.76 20.93 20.92 21.03 21.02 21.11 21.11 Downstream of Culvert 42 and Culvert 44 19.45 17.56 19.93 18.85 20.17 19.35 20.35 19.62 20.52 19.93 Upstream of Existing Culvert 76 17.83 16.67 18.93 18.88 19.44 19.39 19.73 19.66 20.02 19.97 Upstream of Proposed Culvert 76 17.71 16.63 18.90 18.87 19.42 19.38 19.72 19.65 20.01 19.97 Downstream of 19th Street Stormdrain 12.05 12.08 14.17 14.17 14.75 14.75 14.95 14.95 15.15 15.15 Downstream of Utility Berm 17.14 17.03 17.43 17.21 17.60 17.60 17.80 17.80 18.70 18.70 Note: Downstream of Culvert 42 and Culvert 44 and upstream of the existing Culvert 76, the channel flow is confined by the existing fill on both sides of the channel. The proposed condition removes that confinement to restore a more natural interaction with the adjacent floodplain areas. The reduced water levels reported are considered an improvement relative to existing conditions. I -405/ SR167 Interchange Direct Connector Project Page 25 Table 13 – HEC-RAS Existing and Proposed Conditions Water Surface Comparison Future Conditions 2-Year 10-Year 25-Year 50-Year 100-Year Location Exist Prop Exist Prop Exist Prop Exist Prop Exist Prop Upstream of Culvert 42 and Culvert 44 20.52 20.52 20.94 20.94 21.06 21.06 21.14 21.14 21.21 21.21 Downstream of Culvert 42 and Culvert 44 19.69 17.85 20.14 19.21 20.41 19.71 20.58 20.01 20.79 20.34 Upstream of Existing Culvert 76 18.17 17.81 19.29 19.24 19.81 19.75 20.12 20.04 20.44 20.37 Upstream of Proposed Culvert 76 18.09 17.80 19.27 19.24 19.80 19.74 20.11 20.04 20.43 20.37 Downstream of 19th Street Stormdrain 12.18 12.21 14.17 14.17 14.76 14.76 14.96 14.96 15.16 15.16 Downstream of Utility Berm 17.28 17.07 17.47 17.26 17.60 17.60 17.80 17.80 18.70 18.70 The water surface elevations in existing and proposed conditions may be compared using Table 13. The values illustrate that the preliminary Culvert 76 design generally maintains the water surface elevations during design storm events. The design assures that there will be no increase in 100-year water surface elevations throughout the system. There is a minor change in the 2-year event where the model predicts an increase of 0.03-ft at the SW 19th Street storm drain outfall. The current understanding is that this preliminary design will meet the intent of protecting the City of Renton storm drainage facilities, but this will be verified through continued coordination with the City staff. 2.3.6. Proposed Condition Model Results for FEMA Regulated Floodplain The current FEMA Flood Insurance Rate Map (FIRM) provides a 100-year base flood elevation (BFE) of 16-ft, NGVD 29, in Springbrook Creek. The regulated floodplain for Springbrook Creek is designated Zone AE. Additionally, FEMA identifies a floodplain in the wetland east of SR 167 with an identical BFE of 16-ft, NGVD 29 (elevation 19.58-ft NAVD88 – Project datum). The wetland floodplain is designated Zone AH and is identified as flooding impacts from Springbrook Creek. A final set of HEC-RAS models was created to investigate the potential for impacting the existing FEMA regulated floodplains. Recognizing that the current FEMA study is based on analyses that date back to 1985, the new models were used to verify that the preliminary design would meet I -405/ SR167 Interchange Direct Connector Project Page 26 the intent of floodplain regulations. Downstream boundary conditions of 19.58-ft were set at the downstream end of the lower reach and at the downstream end of the wetland reach. All other modeling approaches were left identical to those presented in this report. Table 14 presents a summary of the flow split between the proposed Culvert 76 system and the wetland. This illustrates a less than 1 percent difference between existing and proposed conditions 100-year discharges with FEMA downstream water surface elevations. Table 15 presents a summary of the 100-year water surface elevation comparisons. This table illustrates that the proposed conditions system, as modeled, has no increase in 100-year water surface elevations. Table 14 – HEC-RAS Existing and Proposed Conditions FEMA Boundary Condition Water Surface Comparison Existing Proposed Hydrologic Recurrence Interval Upstream of Culvert 76 and Wetland (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Dishcharge (cfs) Culvert 76 Inlet Discharge (cfs) Wetland Bypass Dishcharge (cfs) 100-Year 126 40.5 85.5 40.7 85.3 Table 15 – HEC-RAS Existing and Proposed Conditions FEMA Boundary Condition Water Surface Comparison 100-Year Water Surface Elevation (ft) Location Existing Proposed Upstream of Culvert 42 and Culvert 44 21.37 21.11 Downstream of Culvert 42 and Culvert 44 21.49 21.34 Upstream of Existing Culvert 76 21.38 21.36 Upstream of Proposed Culvert 76 21.38 21.36 Downstream of 19th Street Stormdrain 19.65 19.65 Downstream of Utility Berm 19.58 19.58 I -405/ SR167 Interchange Direct Connector Project Page 27 3. Conclusions Hydrologic and Hydraulic analyses were completed for the Proposed Culvert replacement. Analyses were completed based on input and data provided by the City of Renton and are intended to support preliminary design in a design build process. As the design process proceeds the hydrologic and hydraulic analyses will need to be revised to represent final design conditions. Analyses completed for the preliminary Culvert 76 design indicate that there are minimal adverse impacts on flow patterns with a properly sized connection between the new WSDOT fish passible structure and the City’s storm drainage system. Initial investigations indicate that a 42-inch diameter CMP with a 0.3-ft deep grouted bottom has negligible impacts to flow patterns upstream and downstream of the proposed C-76 culvert replacement. Minor increases in proposed water surface elevations were observed downstream of the SW 19th Street storm drain system during 2-year flow events. However, all other flow events resulted in no increased water surface elevations. Additionally, analyses conducted assuming FEMA 100-year floodplain water surface elevations at boundary conditions also indicated that proposed improvements would meet the City’s requirements for zero-rise in floodplain. Analyses contained within this report are intended for preliminary design purposes and are not meant for construction. The final design will verify and validate this model. WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘D’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘D’ HEC-RAS Hydraulic Analysis EXISTING HEC-RAS LAYOUT 01000200030004000500060005101520253035DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 Main Channel Distance (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundRollingHills LowerRollingHills UpperEXISTING HEC-RAS PROFILESPRINGBROOK CREEK19th Street Storm 100-YR Flow 73.93 CFSEXISTING CULVERT 76100-YR WSE 20.61CULVERT 42/44 050010001500200025003000101520253035DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 Main Channel Distance (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundRollingHills WetlandRollingHills UpperEXISTING HEC-RAS PROFILE-WETLAND100-YR WSE 20.61CULVERT 42/44 01020304050202224262830323436DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 7155 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010203040501820222426283032DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 7082 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta01020304050601820222426283032DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 7019 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010203040506018202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6998 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 0102030405060192021222324252627DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6869.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0102030405060192021222324252627DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6843.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010203040506018192021222324252627DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6831.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta01020304050601819202122232425DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6761.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 020406080181920212223242526DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6736 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6722 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0204060801001820222426283032DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6600 Culv Culvert 44Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta01020304050607014161820222426283032DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 6600 Culv Culvert 44Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 010203040506070161820222426283032DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5787 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta01020304050607016182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5777 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta01020304050601618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5764 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010203040506016182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5755 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 0204060801618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5727 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0204060801001618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5719 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0204060801001618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5699 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0102030405060708016182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5670 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 020406080100141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5641.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010016182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5618.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0102030405060701416182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5595.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta-150-100-50050100141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5581 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta -50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5566.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5550.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5537 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5507 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta -50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5490 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250300141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5458 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250300141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5387 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-50050100150200250141618202224262830DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5313 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta 050100150200250300121416182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Upper RS = 5000 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-200204060801001201401601416182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3676 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta-200204060801001201401601416182022242628DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3600 Culv Culvert 76Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundIneffBank Sta0204060801001214161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3600 Culv Culvert 76Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundIneffBank Sta 02040608010012141618202224DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3423.989 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta0102030405060708012141618202224DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3393.683 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta0102030405060708012141618202224DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3300 Culv Station (ft)Elevation (ft)LegendWS 10-YearWS 25-YearWS 50-YearWS 100-YearWS 2-YearGroundIneffBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3300 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3060 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3056 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 3000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2755 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2751 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2700 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2700 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2543 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2539 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2500 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2500 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2203 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2199 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010010121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2100 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2100 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2030 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2026 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 2000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 1497 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 1493 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 1400 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 1400 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 1001 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 997 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta020406080100810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 900 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta0204060801006810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 900 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 0204060801006810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 490 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0204060801006810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 486 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0204060801006810121416182022DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 450 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 450 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta 02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 427.3552 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 370.2063 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 106.7341 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 86.6344 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 02040608010012068101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 50 Culv Springbrook Right Bank CulvertStation (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta020406080100120468101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 50 Culv Springbrook Right Bank CulvertStation (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta020406080100120468101214161820DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Lower RS = 0.0000 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta05010015020025014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4902.779 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 05010015020025030035014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4786.615 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta05010015020025030035014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4687.476 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010020030040050014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4581.304 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta010020030040050014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4474.428 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 010020030040050014161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4374.147 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0100200300400500161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4278.601 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta0100200300400500161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4250 Culv Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta050100150200250300350161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4250 Culv Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta 050100150200250300350161820222426DCRollingHillsFinaldesign Plan: Existing Future Flow FD 5/17/2017 River = RollingHills Reach = Wetland RS = 4226.556 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta HEC-RAS Plan: EXFD Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Upper 7155 2-Year 63.90 20.15 22.49 1.99 3.69 17.49 9.63 0.46 Upper 7155 10-Year 84.60 20.15 22.86 2.36 4.09 21.29 10.56 0.47 Upper 7155 25-Year 93.50 20.15 23.01 2.51 4.24 22.87 10.92 0.47 Upper 7155 50-Year 99.70 20.15 23.11 2.61 4.35 23.95 11.18 0.47 Upper 7155 100-Year 105.00 20.15 23.19 2.69 4.43 24.85 11.43 0.48 Upper 7082 2-Year 63.90 19.56 22.12 2.18 4.50 14.73 8.51 0.54 Upper 7082 10-Year 84.60 19.56 22.44 2.50 5.12 17.68 9.57 0.57 Upper 7082 25-Year 93.50 19.56 22.57 2.63 5.38 18.88 10.55 0.59 Upper 7082 50-Year 99.70 19.56 22.65 2.71 5.54 19.78 11.53 0.59 Upper 7082 100-Year 105.00 19.56 22.71 2.77 5.68 20.58 12.34 0.60 Upper 7019 2-Year 63.90 19.67 21.99 1.94 3.51 18.41 10.68 0.44 Upper 7019 10-Year 84.60 19.67 22.34 2.29 3.91 22.40 12.20 0.45 Upper 7019 25-Year 93.50 19.67 22.47 2.43 4.07 24.08 13.16 0.46 Upper 7019 50-Year 99.70 19.67 22.56 2.51 4.18 25.27 13.81 0.46 Upper 7019 100-Year 105.00 19.67 22.63 2.59 4.26 26.30 14.34 0.47 Upper 6998 2-Year 63.90 19.52 21.91 2.08 3.70 18.07 11.21 0.45 Upper 6998 10-Year 84.60 19.52 22.25 2.42 4.14 22.17 12.70 0.47 Upper 6998 25-Year 93.50 19.52 22.38 2.55 4.32 23.85 13.41 0.48 Upper 6998 50-Year 99.70 19.52 22.47 2.64 4.44 25.03 13.99 0.48 Upper 6998 100-Year 105.00 19.52 22.54 2.71 4.54 26.04 14.86 0.49 Upper 6869.5 2-Year 63.90 19.20 21.57 2.10 3.59 18.41 11.18 0.44 Upper 6869.5 10-Year 84.60 19.20 21.90 2.42 4.06 22.37 12.93 0.46 Upper 6869.5 25-Year 93.50 19.20 22.02 2.55 4.25 23.99 13.51 0.47 Upper 6869.5 50-Year 99.70 19.20 22.10 2.63 4.37 25.11 13.89 0.48 Upper 6869.5 100-Year 105.00 19.20 22.17 2.69 4.47 26.03 14.20 0.48 Upper 6843.5 2-Year 63.90 19.01 21.54 2.19 3.23 20.80 10.97 0.38 Upper 6843.5 10-Year 84.60 19.01 21.87 2.52 3.69 24.47 11.46 0.41 Upper 6843.5 25-Year 93.50 19.01 21.99 2.64 3.89 25.87 11.96 0.42 Upper 6843.5 50-Year 99.70 19.01 22.07 2.72 4.02 26.84 12.20 0.43 Upper 6843.5 100-Year 105.00 19.01 22.13 2.79 4.13 27.63 12.40 0.44 Upper 6831.5 2-Year 63.90 18.89 21.52 2.21 3.16 20.83 11.57 0.37 Upper 6831.5 10-Year 84.60 18.89 21.85 2.54 3.61 24.94 12.92 0.40 Upper 6831.5 25-Year 93.50 18.89 21.97 2.66 3.81 26.53 14.43 0.41 Upper 6831.5 50-Year 99.70 18.89 22.05 2.74 3.92 27.71 14.70 0.42 Upper 6831.5 100-Year 105.00 18.89 22.12 2.81 4.02 28.67 14.91 0.42 Upper 6761.5 2-Year 63.90 18.81 21.32 1.99 3.59 18.17 11.41 0.45 Upper 6761.5 10-Year 84.60 18.81 21.63 2.30 4.06 22.51 16.07 0.47 Upper 6761.5 25-Year 93.50 18.81 21.74 2.42 4.23 24.43 16.65 0.48 Upper 6761.5 50-Year 99.70 18.81 21.82 2.49 4.36 25.71 17.60 0.49 Upper 6761.5 100-Year 105.00 18.81 21.88 2.55 4.45 26.83 18.43 0.49 Upper 6736 2-Year 63.90 18.70 21.09 1.76 4.56 14.95 14.90 0.60 Upper 6736 10-Year 84.60 18.70 21.43 2.10 4.84 20.68 18.92 0.59 Upper 6736 25-Year 93.50 18.70 21.56 2.23 4.94 23.37 24.10 0.58 Upper 6736 50-Year 99.70 18.70 21.65 2.33 4.96 25.77 26.81 0.57 Upper 6736 100-Year 105.00 18.70 21.74 2.41 4.94 28.12 28.24 0.56 Upper 6722 2-Year 63.90 18.23 20.52 1.44 6.86 9.34 6.80 1.01 Upper 6722 10-Year 84.60 18.23 20.94 1.85 6.82 13.70 12.53 0.88 Upper 6722 25-Year 93.50 18.23 21.06 1.97 6.96 15.26 13.18 0.87 Upper 6722 50-Year 99.70 18.23 21.14 2.05 7.06 16.32 13.59 0.87 Upper 6722 100-Year 105.00 18.23 21.21 2.12 7.13 17.27 13.94 0.86 Upper 6600 Culvert Upper 5787 2-Year 63.90 16.40 19.71 2.78 2.14 41.29 19.10 0.23 Upper 5787 10-Year 84.60 16.40 20.18 3.25 2.36 50.42 19.52 0.23 Upper 5787 25-Year 93.50 16.40 20.47 3.55 2.36 56.17 19.63 0.22 Upper 5787 50-Year 99.70 16.40 20.65 3.73 2.38 59.72 19.70 0.22 Upper 5787 100-Year 105.00 16.40 20.90 3.97 2.33 64.63 19.79 0.21 EXISTING FUTURE FLOW HEC-RAS OUTPUT TABLE HEC-RAS Plan: EXFD (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Upper 5777 2-Year 63.90 16.40 19.65 2.58 2.62 35.59 20.44 0.29 Upper 5777 10-Year 84.60 16.40 20.11 3.02 2.85 45.97 25.87 0.29 Upper 5777 25-Year 93.50 16.40 20.42 3.32 2.80 54.38 29.27 0.27 Upper 5777 50-Year 99.70 16.40 20.60 3.51 2.78 59.90 30.13 0.26 Upper 5777 100-Year 105.00 16.40 20.86 3.76 2.66 67.82 31.14 0.24 Upper 5764 2-Year 63.90 17.04 19.52 1.95 3.52 18.16 9.32 0.44 Upper 5764 10-Year 84.60 17.04 19.98 2.37 3.72 24.32 18.91 0.43 Upper 5764 25-Year 93.50 17.04 20.32 2.70 3.47 31.59 23.96 0.37 Upper 5764 50-Year 99.70 17.04 20.52 2.90 3.35 36.69 26.33 0.35 Upper 5764 100-Year 105.00 17.04 20.80 3.19 3.10 44.23 27.31 0.31 Upper 5755 2-Year 63.90 16.71 19.53 2.05 2.93 21.86 11.40 0.36 Upper 5755 10-Year 84.60 16.71 20.00 2.50 3.11 28.47 18.54 0.35 Upper 5755 25-Year 93.50 16.71 20.33 2.84 2.92 36.32 25.67 0.31 Upper 5755 50-Year 99.70 16.71 20.53 3.04 2.81 41.62 26.59 0.28 Upper 5755 100-Year 105.00 16.71 20.82 3.32 2.57 49.24 27.58 0.25 Upper 5727 2-Year 63.90 16.64 19.39 2.39 3.05 23.30 17.24 0.35 Upper 5727 10-Year 84.60 16.64 19.90 2.90 3.12 33.93 23.59 0.32 Upper 5727 25-Year 93.50 16.64 20.27 3.26 2.86 42.74 24.46 0.28 Upper 5727 50-Year 99.70 16.64 20.48 3.47 2.77 47.99 24.96 0.26 Upper 5727 100-Year 105.00 16.64 20.77 3.77 2.57 55.38 25.65 0.23 Upper 5719 2-Year 63.90 16.41 19.38 2.25 2.86 24.14 15.67 0.34 Upper 5719 10-Year 84.60 16.41 19.88 2.75 2.98 33.36 20.88 0.32 Upper 5719 25-Year 93.50 16.41 20.25 3.12 2.80 41.46 23.19 0.28 Upper 5719 50-Year 99.70 16.41 20.46 3.33 2.73 46.53 24.50 0.26 Upper 5719 100-Year 105.00 16.41 20.75 3.63 2.55 54.02 26.26 0.24 Upper 5699 2-Year 63.90 16.51 19.28 2.05 3.01 23.43 17.82 0.37 Upper 5699 10-Year 84.60 16.51 19.82 2.58 3.00 33.89 21.18 0.33 Upper 5699 25-Year 93.50 16.51 20.20 2.97 2.76 42.57 23.62 0.28 Upper 5699 50-Year 99.70 16.51 20.42 3.19 2.67 47.90 25.00 0.26 Upper 5699 100-Year 105.00 16.51 20.73 3.49 2.48 55.81 26.95 0.23 Upper 5670 2-Year 63.90 16.17 19.20 2.49 2.58 25.93 13.23 0.29 Upper 5670 10-Year 84.60 16.17 19.74 3.03 2.76 33.70 17.55 0.28 Upper 5670 25-Year 93.50 16.17 20.15 3.43 2.60 42.14 21.96 0.25 Upper 5670 50-Year 99.70 16.17 20.37 3.66 2.54 47.23 23.15 0.23 Upper 5670 100-Year 105.00 16.17 20.69 3.97 2.38 54.77 24.81 0.21 Upper 5641.5 2-Year 63.90 15.73 19.14 2.84 2.42 28.55 16.36 0.25 Upper 5641.5 10-Year 84.60 15.73 19.70 3.39 2.52 38.98 20.70 0.24 Upper 5641.5 25-Year 93.50 15.73 20.12 3.81 2.34 48.23 23.41 0.21 Upper 5641.5 50-Year 99.70 15.73 20.35 4.04 2.29 53.79 24.90 0.20 Upper 5641.5 100-Year 105.00 15.73 20.67 4.36 2.13 62.08 26.65 0.18 Upper 5618.5 2-Year 63.90 16.25 18.96 1.98 3.39 19.58 14.30 0.42 Upper 5618.5 10-Year 84.60 16.25 19.57 2.59 3.23 30.70 21.05 0.35 Upper 5618.5 25-Year 93.50 16.25 20.04 3.06 2.82 41.26 23.83 0.28 Upper 5618.5 50-Year 99.70 16.25 20.28 3.31 2.69 47.30 25.28 0.26 Upper 5618.5 100-Year 105.00 16.25 20.62 3.65 2.44 56.20 27.03 0.23 Upper 5595.5 2-Year 63.90 15.59 18.89 2.83 2.87 26.77 17.58 0.30 Upper 5595.5 10-Year 84.60 15.59 19.52 3.46 2.86 38.82 20.73 0.27 Upper 5595.5 25-Year 93.50 15.59 20.00 3.94 2.61 51.32 28.46 0.23 Upper 5595.5 50-Year 99.70 15.59 20.25 4.19 2.51 58.80 31.01 0.22 Upper 5595.5 100-Year 105.00 15.59 20.60 4.54 2.33 70.54 36.94 0.19 Upper 5581 2-Year 63.90 15.47 18.80 2.79 3.10 21.09 34.64 0.33 Upper 5581 10-Year 84.60 15.47 19.42 3.42 3.23 30.11 99.74 0.31 Upper 5581 25-Year 93.50 15.47 19.96 3.95 2.75 68.37 161.86 0.24 Upper 5581 50-Year 99.70 15.47 20.25 4.25 2.16 117.20 166.90 0.18 Upper 5581 100-Year 105.00 15.47 20.62 4.61 1.59 178.52 169.18 0.13 Upper 5566.5 2-Year 63.90 15.37 18.76 2.62 3.05 20.97 143.78 0.33 Upper 5566.5 10-Year 84.60 15.37 19.42 3.28 2.88 68.26 174.22 0.28 HEC-RAS Plan: EXFD (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Upper 5566.5 25-Year 93.50 15.37 19.99 3.85 1.85 169.08 179.41 0.17 Upper 5566.5 50-Year 99.70 15.37 20.27 4.12 1.57 218.15 180.93 0.14 Upper 5566.5 100-Year 105.00 15.37 20.62 4.47 1.28 282.52 182.71 0.11 Upper 5550.5 2-Year 63.90 15.31 18.74 2.26 3.02 21.61 155.87 0.35 Upper 5550.5 10-Year 84.60 15.31 19.46 2.98 2.08 126.93 187.61 0.21 Upper 5550.5 25-Year 93.50 15.31 20.00 3.53 1.37 230.83 193.02 0.13 Upper 5550.5 50-Year 99.70 15.31 20.27 3.79 1.19 282.83 194.39 0.11 Upper 5550.5 100-Year 105.00 15.31 20.62 4.15 0.99 351.40 195.60 0.09 Upper 5537 2-Year 63.90 15.09 18.68 2.84 3.31 20.43 161.48 0.35 Upper 5537 10-Year 84.60 15.09 19.45 3.61 2.19 140.67 191.62 0.20 Upper 5537 25-Year 93.50 15.09 20.00 4.16 1.44 248.75 199.65 0.12 Upper 5537 50-Year 99.70 15.09 20.27 4.43 1.25 302.66 200.57 0.10 Upper 5537 100-Year 105.00 15.09 20.62 4.78 1.04 373.56 201.78 0.08 Upper 5507 2-Year 63.90 15.19 18.64 2.37 3.18 39.08 184.28 0.36 Upper 5507 10-Year 84.60 15.19 19.46 3.19 1.58 196.02 197.51 0.16 Upper 5507 25-Year 93.50 15.19 20.00 3.73 1.10 305.17 203.38 0.10 Upper 5507 50-Year 99.70 15.19 20.27 4.00 0.98 360.03 204.63 0.09 Upper 5507 100-Year 105.00 15.19 20.62 4.35 0.84 432.41 206.27 0.07 Upper 5490 2-Year 63.90 14.73 18.67 2.83 2.13 38.90 188.80 0.22 Upper 5490 10-Year 84.60 14.73 19.45 3.60 1.47 187.55 194.89 0.14 Upper 5490 25-Year 93.50 14.73 20.00 4.15 1.09 295.52 199.25 0.09 Upper 5490 50-Year 99.70 14.73 20.26 4.42 0.99 349.70 202.24 0.08 Upper 5490 100-Year 105.00 14.73 20.62 4.77 0.86 421.72 205.77 0.07 Upper 5458 2-Year 63.90 15.03 18.51 2.90 3.55 32.64 212.51 0.37 Upper 5458 10-Year 84.60 15.03 19.45 3.84 1.44 236.68 221.07 0.13 Upper 5458 25-Year 93.50 15.03 20.00 4.39 1.00 359.21 224.37 0.08 Upper 5458 50-Year 99.70 15.03 20.27 4.66 0.88 419.97 225.67 0.07 Upper 5458 100-Year 105.00 15.03 20.62 5.01 0.76 500.03 227.32 0.06 Upper 5387 2-Year 63.90 14.90 18.32 2.97 3.83 45.54 210.70 0.39 Upper 5387 10-Year 84.60 14.90 19.43 4.08 1.26 287.27 223.97 0.11 Upper 5387 25-Year 93.50 14.90 19.99 4.64 0.92 413.53 230.60 0.07 Upper 5387 50-Year 99.70 14.90 20.26 4.91 0.83 476.51 233.84 0.07 Upper 5387 100-Year 105.00 14.90 20.62 5.26 0.72 559.84 235.24 0.05 Upper 5313 2-Year 63.90 14.29 18.40 3.45 1.62 142.60 207.51 0.15 Upper 5313 10-Year 84.60 14.29 19.43 4.48 0.93 362.88 221.12 0.08 Upper 5313 25-Year 93.50 14.29 19.99 5.03 0.75 488.20 228.50 0.06 Upper 5313 50-Year 99.70 14.29 20.26 5.31 0.70 550.42 229.14 0.05 Upper 5313 100-Year 105.00 14.29 20.61 5.66 0.63 631.95 229.76 0.05 Upper 5000 2-Year 63.90 13.90 18.35 3.27 1.12 194.63 233.03 0.11 Upper 5000 10-Year 84.60 13.90 19.42 4.33 0.68 444.32 235.91 0.06 Upper 5000 25-Year 93.50 13.90 19.98 4.89 0.57 577.52 237.17 0.05 Upper 5000 50-Year 99.70 13.90 20.25 5.17 0.54 642.40 237.78 0.04 Upper 5000 100-Year 105.00 13.90 20.61 5.52 0.49 727.42 238.58 0.04 Wetland 4902.779 2-Year 12.09 15.99 18.36 2.15 0.03 412.95 214.78 0.00 Wetland 4902.779 10-Year 36.63 15.99 19.42 3.21 0.06 643.77 220.85 0.01 Wetland 4902.779 25-Year 52.19 15.99 19.98 3.77 0.07 768.74 223.30 0.01 Wetland 4902.779 50-Year 59.74 15.99 20.25 4.05 0.08 829.88 224.41 0.01 Wetland 4902.779 100-Year 69.07 15.99 20.61 4.40 0.08 910.23 225.86 0.01 Wetland 4786.615 2-Year 12.09 15.55 18.36 2.55 0.02 585.60 280.85 0.00 Wetland 4786.615 10-Year 36.63 15.55 19.42 3.61 0.05 888.62 289.85 0.00 Wetland 4786.615 25-Year 52.19 15.55 19.98 4.17 0.05 1052.49 292.70 0.00 Wetland 4786.615 50-Year 59.74 15.55 20.25 4.44 0.06 1132.64 294.30 0.00 Wetland 4786.615 100-Year 69.07 15.55 20.61 4.80 0.06 1238.06 296.53 0.00 Wetland 4687.476 2-Year 12.09 14.98 18.36 2.80 0.02 684.12 302.48 0.00 Wetland 4687.476 10-Year 36.63 14.98 19.42 3.86 0.04 1013.99 317.05 0.00 Wetland 4687.476 25-Year 52.19 14.98 19.98 4.42 0.05 1193.13 319.83 0.00 Wetland 4687.476 50-Year 59.74 14.98 20.25 4.69 0.05 1280.66 321.18 0.00 FLOWS TO PANTHER CREEK WETLAND HEC-RAS Plan: EXFD (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Wetland 4687.476 100-Year 69.07 14.98 20.61 5.05 0.05 1395.60 322.95 0.00 Wetland 4581.304 2-Year 12.09 14.75 18.36 2.83 0.02 744.06 326.01 0.00 Wetland 4581.304 10-Year 36.63 14.75 19.42 3.89 0.04 1107.01 359.72 0.00 Wetland 4581.304 25-Year 52.19 14.75 19.98 4.45 0.05 1314.40 377.64 0.00 Wetland 4581.304 50-Year 59.74 14.75 20.25 4.73 0.05 1418.72 386.34 0.00 Wetland 4581.304 100-Year 69.07 14.75 20.61 5.08 0.05 1558.52 395.45 0.00 Wetland 4474.428 2-Year 12.09 15.33 18.36 2.75 0.01 930.49 410.46 0.00 Wetland 4474.428 10-Year 36.63 15.33 19.42 3.81 0.03 1367.32 414.98 0.00 Wetland 4474.428 25-Year 52.19 15.33 19.98 4.37 0.04 1601.45 417.44 0.00 Wetland 4474.428 50-Year 59.74 15.33 20.25 4.64 0.04 1715.61 418.64 0.00 Wetland 4474.428 100-Year 69.07 15.33 20.61 5.00 0.04 1865.29 420.20 0.00 Wetland 4374.147 2-Year 12.09 14.33 18.36 3.23 0.02 943.58 425.04 0.00 Wetland 4374.147 10-Year 36.63 14.33 19.41 4.29 0.03 1395.95 429.74 0.00 Wetland 4374.147 25-Year 52.19 14.33 19.98 4.85 0.04 1638.38 432.23 0.00 Wetland 4374.147 50-Year 59.74 14.33 20.25 5.12 0.04 1756.59 433.44 0.00 Wetland 4374.147 100-Year 69.07 14.33 20.61 5.48 0.04 1911.55 435.03 0.00 Wetland 4278.601 2-Year 12.09 16.89 18.36 1.14 0.03 367.10 345.36 0.01 Wetland 4278.601 10-Year 36.63 16.89 19.41 2.20 0.05 755.98 389.49 0.01 Wetland 4278.601 25-Year 52.19 16.89 19.98 2.76 0.06 977.33 394.82 0.01 Wetland 4278.601 50-Year 59.74 16.89 20.25 3.03 0.06 1085.29 395.83 0.01 Wetland 4278.601 100-Year 69.07 16.89 20.61 3.39 0.06 1226.79 397.16 0.01 Wetland 4250 Culvert Wetland 4226.556 2-Year 12.09 17.17 17.34 0.08 1.65 5.80 39.04 1.01 Wetland 4226.556 10-Year 36.63 17.17 17.50 0.16 2.42 14.24 66.65 1.06 Wetland 4226.556 25-Year 52.19 17.17 17.60 0.22 2.30 22.18 84.77 0.87 Wetland 4226.556 50-Year 59.74 17.17 17.80 0.34 1.43 42.27 110.39 0.43 Wetland 4226.556 100-Year 69.07 17.17 18.70 1.24 0.39 245.51 247.39 0.06 Lower 3676 2-Year 69.11 14.50 18.29 3.12 2.23 51.86 88.35 0.22 Lower 3676 10-Year 72.37 14.50 19.38 4.21 1.31 153.53 111.51 0.11 Lower 3676 25-Year 70.81 14.50 19.97 4.80 0.94 220.00 113.15 0.08 Lower 3676 50-Year 73.26 14.50 20.24 5.07 0.86 250.73 113.90 0.07 Lower 3676 100-Year 73.93 14.50 20.59 5.43 0.76 291.16 114.88 0.06 Lower 3600 Culvert Lower 3423.989 2-Year 69.11 12.59 17.16 4.05 3.28 21.08 5.20 0.29 Lower 3423.989 10-Year 72.37 12.59 18.12 5.01 2.78 26.05 5.26 0.22 Lower 3423.989 25-Year 70.81 12.59 18.77 5.66 2.41 29.42 5.30 0.18 Lower 3423.989 50-Year 73.26 12.59 18.96 5.85 2.41 30.39 5.31 0.18 Lower 3423.989 100-Year 73.93 12.59 19.29 6.18 2.30 32.12 5.33 0.16 Lower 3393.683 2-Year 69.11 12.59 17.20 4.23 2.72 25.40 6.03 0.23 Lower 3393.683 10-Year 72.37 12.59 18.14 5.18 2.33 31.07 6.30 0.18 Lower 3393.683 25-Year 70.81 12.59 18.79 5.82 2.03 34.92 6.49 0.15 Lower 3393.683 50-Year 73.26 12.59 18.97 6.01 2.03 36.04 6.54 0.15 Lower 3393.683 100-Year 73.93 12.59 19.30 6.34 1.94 38.03 6.64 0.14 Lower 3300 Culvert Lower 3060 2-Year 69.11 11.62 16.97 5.08 2.44 28.28 5.57 0.19 Lower 3060 10-Year 72.37 11.62 17.86 5.87 2.18 33.27 5.67 0.16 Lower 3060 25-Year 70.81 11.62 18.50 6.44 1.92 36.94 5.73 0.13 Lower 3060 50-Year 73.26 11.62 18.67 6.59 1.93 37.88 5.75 0.13 Lower 3060 100-Year 73.93 11.62 18.99 6.87 1.86 39.74 5.79 0.13 Lower 3056 2-Year 69.11 11.62 16.97 5.08 2.44 28.27 5.57 0.19 Lower 3056 10-Year 72.37 11.62 17.86 5.87 2.18 33.26 5.67 0.16 Lower 3056 25-Year 70.81 11.62 18.50 6.44 1.92 36.93 5.73 0.13 Lower 3056 50-Year 73.26 11.62 18.67 6.59 1.93 37.88 5.75 0.13 Lower 3056 100-Year 73.93 11.62 18.99 6.87 1.86 39.73 5.79 0.13 100-YR WSE UPSTREAM OF CUVERT 76 100-YR FLOW TO CITY OF RENTON SYSTEM HEC-RAS Plan: EXFD (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Lower 3000 Culvert Lower 2755 2-Year 69.11 11.16 16.71 5.27 2.36 29.31 5.56 0.18 Lower 2755 10-Year 72.37 11.16 17.56 6.03 2.12 34.06 5.65 0.15 Lower 2755 25-Year 70.81 11.16 18.21 6.61 1.88 37.76 5.72 0.13 Lower 2755 50-Year 73.26 11.16 18.35 6.73 1.90 38.57 5.73 0.13 Lower 2755 100-Year 73.93 11.16 18.66 7.00 1.83 40.36 5.76 0.12 Lower 2751 2-Year 88.40 11.16 16.64 5.21 3.05 28.94 5.56 0.24 Lower 2751 10-Year 82.66 11.16 17.53 6.01 2.44 33.92 5.65 0.18 Lower 2751 25-Year 81.31 11.16 18.19 6.59 2.16 37.64 5.71 0.15 Lower 2751 50-Year 81.76 11.16 18.33 6.72 2.12 38.47 5.73 0.14 Lower 2751 100-Year 81.67 11.16 18.65 6.99 2.03 40.29 5.76 0.14 Lower 2700 Culvert Lower 2543 2-Year 88.40 10.80 16.26 5.20 3.07 28.78 5.54 0.24 Lower 2543 10-Year 82.66 10.80 17.18 6.03 2.44 33.90 5.63 0.18 Lower 2543 25-Year 81.31 10.80 17.84 6.61 2.16 37.62 5.69 0.15 Lower 2543 50-Year 81.76 10.80 17.98 6.74 2.13 38.42 5.70 0.14 Lower 2543 100-Year 81.67 10.80 18.29 7.01 2.03 40.21 5.73 0.14 Lower 2539 2-Year 88.40 10.80 16.26 5.20 3.07 28.77 5.54 0.24 Lower 2539 10-Year 82.66 10.80 17.18 6.03 2.44 33.90 5.63 0.18 Lower 2539 25-Year 81.31 10.80 17.84 6.61 2.16 37.62 5.69 0.15 Lower 2539 50-Year 81.76 10.80 17.98 6.74 2.13 38.42 5.70 0.14 Lower 2539 100-Year 81.67 10.80 18.29 7.01 2.03 40.21 5.73 0.14 Lower 2500 Culvert Lower 2203 2-Year 88.40 10.29 15.79 5.24 3.06 28.92 5.51 0.24 Lower 2203 10-Year 82.66 10.29 16.75 6.11 2.41 34.25 5.60 0.17 Lower 2203 25-Year 81.31 10.29 17.41 6.70 2.14 37.98 5.67 0.15 Lower 2203 50-Year 81.76 10.29 17.55 6.82 2.11 38.75 5.68 0.14 Lower 2203 100-Year 81.67 10.29 17.86 7.10 2.02 40.51 5.71 0.13 Lower 2199 2-Year 88.40 10.29 15.79 5.24 3.06 28.91 5.51 0.24 Lower 2199 10-Year 82.66 10.29 16.75 6.11 2.41 34.24 5.60 0.17 Lower 2199 25-Year 81.31 10.29 17.41 6.70 2.14 37.98 5.66 0.15 Lower 2199 50-Year 81.76 10.29 17.55 6.82 2.11 38.74 5.68 0.14 Lower 2199 100-Year 81.67 10.29 17.86 7.10 2.02 40.51 5.71 0.13 Lower 2100 Culvert Lower 2030 2-Year 88.40 9.94 15.42 5.23 3.07 28.77 5.50 0.24 Lower 2030 10-Year 82.66 9.94 16.41 6.13 2.41 34.24 5.58 0.17 Lower 2030 25-Year 81.31 9.94 17.07 6.73 2.14 37.98 5.65 0.15 Lower 2030 50-Year 81.76 9.94 17.20 6.84 2.11 38.71 5.66 0.14 Lower 2030 100-Year 81.67 9.94 17.51 7.12 2.02 40.46 5.68 0.13 Lower 2026 2-Year 88.40 9.94 15.42 5.23 3.07 28.76 5.50 0.24 Lower 2026 10-Year 82.66 9.94 16.41 6.13 2.41 34.23 5.58 0.17 Lower 2026 25-Year 81.31 9.94 17.07 6.73 2.14 37.97 5.65 0.15 Lower 2026 50-Year 81.76 9.94 17.20 6.84 2.11 38.70 5.66 0.14 Lower 2026 100-Year 81.67 9.94 17.51 7.12 2.02 40.45 5.68 0.13 Lower 2000 Culvert Lower 1497 2-Year 88.40 9.14 14.77 5.38 3.00 29.46 5.47 0.23 Lower 1497 10-Year 82.66 9.14 15.82 6.34 2.34 35.25 5.56 0.16 Lower 1497 25-Year 81.31 9.14 16.49 6.95 2.08 39.03 5.62 0.14 Lower 1497 50-Year 81.76 9.14 16.61 7.05 2.06 39.72 5.63 0.14 Lower 1497 100-Year 81.67 9.14 16.92 7.33 1.97 41.45 5.66 0.13 Lower 1493 2-Year 88.40 9.14 14.76 5.38 3.00 29.45 5.47 0.23 Lower 1493 10-Year 82.66 9.14 15.81 6.34 2.35 35.25 5.56 0.16 Lower 1493 25-Year 81.31 9.14 16.49 6.94 2.08 39.03 5.62 0.14 Lower 1493 50-Year 81.76 9.14 16.61 7.05 2.06 39.71 5.63 0.14 FLOWS ARE REDUCED DURING HIGHER EVENTS BY FLOW SPLIT HYDRAULICS HEC-RAS Plan: EXFD (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft/s) (sq ft) (ft) Lower 1493 100-Year 81.67 9.14 16.92 7.33 1.97 41.44 5.66 0.13 Lower 1400 Culvert Lower 1001 2-Year 88.40 8.48 14.20 5.48 2.96 29.89 5.46 0.22 Lower 1001 10-Year 82.66 8.48 15.30 6.48 2.30 35.95 5.54 0.16 Lower 1001 25-Year 81.31 8.48 15.98 7.10 2.04 39.77 5.60 0.14 Lower 1001 50-Year 81.76 8.48 16.10 7.21 2.02 40.41 5.61 0.13 Lower 1001 100-Year 81.67 8.48 16.40 7.48 1.94 42.12 5.63 0.12 Lower 997 2-Year 88.40 8.48 14.19 5.48 2.96 29.88 5.46 0.22 Lower 997 10-Year 82.66 8.48 15.30 6.48 2.30 35.94 5.54 0.16 Lower 997 25-Year 81.31 8.48 15.98 7.10 2.05 39.76 5.60 0.14 Lower 997 50-Year 81.76 8.48 16.10 7.20 2.02 40.40 5.61 0.13 Lower 997 100-Year 81.67 8.48 16.40 7.48 1.94 42.12 5.63 0.12 Lower 900 Culvert Lower 490 2-Year 88.40 7.72 13.56 5.60 2.90 30.47 5.44 0.22 Lower 490 10-Year 82.66 7.72 14.72 6.67 2.24 36.85 5.53 0.15 Lower 490 25-Year 81.31 7.72 15.42 7.30 2.00 40.71 5.58 0.13 Lower 490 50-Year 81.76 7.72 15.52 7.39 1.98 41.31 5.59 0.13 Lower 490 100-Year 81.67 7.72 15.83 7.67 1.90 43.01 5.61 0.12 Lower 486 2-Year 88.40 7.72 13.56 5.60 2.90 30.46 5.44 0.22 Lower 486 10-Year 82.66 7.72 14.72 6.67 2.24 36.84 5.53 0.15 Lower 486 25-Year 81.31 7.72 15.42 7.30 2.00 40.71 5.58 0.13 Lower 486 50-Year 81.76 7.72 15.52 7.39 1.98 41.31 5.59 0.13 Lower 486 100-Year 81.67 7.72 15.83 7.67 1.90 43.01 5.61 0.12 Lower 450 Culvert Lower 427.3552 2-Year 88.40 7.50 13.41 4.96 0.67 158.76 45.43 0.05 Lower 427.3552 10-Year 82.66 7.50 14.55 6.10 0.50 214.80 52.30 0.04 Lower 427.3552 25-Year 81.31 7.50 15.24 6.79 0.43 252.20 56.42 0.03 Lower 427.3552 50-Year 81.76 7.50 15.35 6.90 0.43 258.08 57.05 0.03 Lower 427.3552 100-Year 81.67 7.50 15.65 7.20 0.41 275.42 58.84 0.03 Lower 370.2063 2-Year 88.40 7.50 13.41 4.96 0.67 158.92 45.55 0.05 Lower 370.2063 10-Year 82.66 7.50 14.55 6.10 0.50 215.16 52.47 0.04 Lower 370.2063 25-Year 81.31 7.50 15.24 6.79 0.43 252.71 56.62 0.03 Lower 370.2063 50-Year 81.76 7.50 15.35 6.90 0.43 258.61 57.25 0.03 Lower 370.2063 100-Year 81.67 7.50 15.65 7.20 0.41 276.01 59.05 0.03 Lower 106.7341 2-Year 88.40 7.30 13.40 5.08 0.66 161.54 45.39 0.05 Lower 106.7341 10-Year 82.66 7.30 14.55 6.23 0.49 217.75 52.28 0.03 Lower 106.7341 25-Year 81.31 7.30 15.24 6.92 0.43 255.19 56.41 0.03 Lower 106.7341 50-Year 81.76 7.30 15.34 7.02 0.42 261.08 57.04 0.03 Lower 106.7341 100-Year 81.67 7.30 15.64 7.32 0.40 278.43 58.83 0.03 Lower 86.6344 2-Year 88.40 7.30 13.40 5.18 0.65 164.23 45.38 0.05 Lower 86.6344 10-Year 82.66 7.30 14.55 6.33 0.48 220.44 52.28 0.03 Lower 86.6344 25-Year 81.31 7.30 15.24 7.02 0.42 257.89 56.41 0.03 Lower 86.6344 50-Year 81.76 7.30 15.34 7.13 0.42 263.78 57.03 0.03 Lower 86.6344 100-Year 81.67 7.30 15.64 7.43 0.39 281.12 58.83 0.03 Lower 50 Culvert Lower 0.0000 2-Year 88.40 5.00 13.00 6.10 0.56 179.47 42.98 0.04 Lower 0.0000 10-Year 82.66 5.00 14.20 7.30 0.43 235.36 50.17 0.03 Lower 0.0000 25-Year 81.31 5.00 14.90 8.00 0.38 271.95 54.37 0.02 Lower 0.0000 50-Year 81.76 5.00 15.00 8.10 0.38 277.42 54.97 0.02 Lower 0.0000 100-Year 81.67 5.00 15.30 8.40 0.36 294.18 56.77 0.02 FLOWS ARE REDUCED DURING HIGHER EVENTS BY FLOW SPLIT HYDRAULICS POST-PROJECT HEC-RAS LAYOUT 01000200030004000500060005101520253035DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureMain Channel Distance (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundRollingHills LowerRollingHills Upper19th Street Storm100-YR Flow 73.81 CFSSPRINGBROOK CREEKCULVERT 76100-YR WSE 20.12NEW ROLLING HILLS CREEKCULVERT 42/44POST PROJECT HEC-RAS PROFILE 01020304050202224262830323436DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 7155 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 010203040501820222426283032DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 7082 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 01020304050601820222426283032DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 7019 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 010203040506018202224262830DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6998 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 0102030405060192021222324252627DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6869.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 0102030405060192021222324252627DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6843.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 010203040506018192021222324252627DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6831.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 01020304050601819202122232425DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6761.5 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 020406080181920212223242526DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6736 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 020406080100182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6722 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 0204060801001820222426283032DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6600 Culv Culvert 44Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.03.05 0102030405014161820222426283032DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 6600 Culv Culvert 44Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 010203040501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5746 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 0102030405014161820222426DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5737 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 020406080100141618202224262830DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5717 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 020406080100120141618202224262830DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5687 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 02040608010012014014161820222426283032DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5655 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 020406080100120140141618202224262830DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5619 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 020406080100120140160180141618202224262830DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5579 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 0501001502001416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5542 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.05.05.05 0501001502001416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5519 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5484 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5445 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5379 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5313 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5265 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 0501001502002501214161820222426DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5146 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 050100150200250300350121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 5012 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 -100-50050100150200250300121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 4909 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 -200-1000100200300121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 4817 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 -200-1000100200300121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 4711 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 -200-1000100200300400121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 4619 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 050100150200250300350121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Upper RS = 4541 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.05.05 05010015020025030010121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 3016 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.03.05 05010015020025010121416182022242628DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 3003 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundIneffBank Sta.05.03.05 05010015020025051015202530DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2800 Culv Station (ft)Elevation (ft)LegendWS 10-YearWS 25-YearWS 50-YearWS 100-YearWS 2-YearGroundIneffBank Sta.05.03.05 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2800 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2788 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2771 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2720 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2720 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2716 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2708 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2550 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2550 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2543 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2539 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2500 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2500 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2203 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2199 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 02040608010010121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2100 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2100 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2030 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2026 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 2000 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 1497 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 1493 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 1400 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 1400 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 1001 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 997 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 020406080100810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 900 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 0204060801006810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 900 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 0204060801006810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 490 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 0204060801006810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 486 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.1.012.1 0204060801006810121416182022DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 450 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.1.012.1 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 450 Culv Station (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.07.03.07 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 427.3552 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.07.03.07 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 370.2063 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.07.03.07 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 106.7341 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.07.03.07 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 86.6344 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.07.03.07 02040608010012068101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 50 Culv Springbrook Right Bank CulvertStation (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.07.03.07 020406080100120468101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 50 Culv Springbrook Right Bank CulvertStation (ft)Elevation (ft)LegendWS 2-YearWS 10-YearWS 25-YearWS 50-YearWS 100-YearGroundBank Sta.07.03.07 020406080100120468101214161820DCRollingHillsREV Geom: PostProject Flow: Proposed_FutureRiver = RollingHills Reach = Lower RS = 0.0000 Station (ft)Elevation (ft)LegendWS 100-YearWS 50-YearWS 25-YearWS 10-YearWS 2-YearGroundBank Sta.07.03.07 HEC-RAS Plan: PostNoBerm Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 7155 2-Year 63.90 20.15 22.49 1.99 1.62 0.002925 3.69 17.49 9.63 Upper 7155 10-Year 84.60 20.15 22.86 2.36 1.92 0.002852 4.09 21.29 10.56 Upper 7155 25-Year 93.50 20.15 23.01 2.51 2.04 0.002833 4.24 22.87 10.92 Upper 7155 50-Year 99.70 20.15 23.11 2.61 2.12 0.002826 4.35 23.95 11.18 Upper 7155 100-Year 105.00 20.15 23.19 2.69 2.18 0.002826 4.43 24.85 11.43 Upper 7082 2-Year 63.90 19.56 22.12 2.18 1.64 0.004273 4.50 14.73 8.51 Upper 7082 10-Year 84.60 19.56 22.44 2.50 1.88 0.004598 5.12 17.68 9.57 Upper 7082 25-Year 93.50 19.56 22.57 2.62 1.97 0.004762 5.38 18.87 10.55 Upper 7082 50-Year 99.70 19.56 22.65 2.71 2.04 0.004855 5.54 19.78 11.53 Upper 7082 100-Year 105.00 19.56 22.71 2.77 2.09 0.004925 5.68 20.58 12.34 Upper 7019 2-Year 63.90 19.67 21.99 1.94 1.57 0.002755 3.51 18.41 10.68 Upper 7019 10-Year 84.60 19.67 22.34 2.29 1.85 0.002750 3.91 22.40 12.20 Upper 7019 25-Year 93.50 19.67 22.47 2.43 1.95 0.002769 4.07 24.07 13.16 Upper 7019 50-Year 99.70 19.67 22.56 2.51 2.02 0.002776 4.18 25.27 13.81 Upper 7019 100-Year 105.00 19.67 22.63 2.59 2.08 0.002781 4.26 26.30 14.34 Upper 6998 2-Year 63.90 19.52 21.91 2.08 1.70 0.002747 3.70 18.07 11.21 Upper 6998 10-Year 84.60 19.52 22.25 2.42 1.98 0.002810 4.14 22.17 12.70 Upper 6998 25-Year 93.50 19.52 22.38 2.55 2.09 0.002853 4.32 23.84 13.41 Upper 6998 50-Year 99.70 19.52 22.47 2.64 2.16 0.002877 4.44 25.03 13.99 Upper 6998 100-Year 105.00 19.52 22.54 2.71 2.22 0.002907 4.54 26.04 14.86 Upper 6869.5 2-Year 63.90 19.20 21.57 2.10 1.68 0.002633 3.59 18.41 11.18 Upper 6869.5 10-Year 84.60 19.20 21.90 2.42 1.94 0.002773 4.06 22.37 12.93 Upper 6869.5 25-Year 93.50 19.20 22.02 2.55 2.04 0.002845 4.25 23.98 13.50 Upper 6869.5 50-Year 99.70 19.20 22.10 2.63 2.11 0.002882 4.37 25.11 13.89 Upper 6869.5 100-Year 105.00 19.20 22.17 2.69 2.16 0.002923 4.47 26.03 14.20 Upper 6843.5 2-Year 63.90 19.01 21.54 2.19 1.87 0.001835 3.23 20.80 10.97 Upper 6843.5 10-Year 84.60 19.01 21.87 2.52 2.15 0.001997 3.69 24.47 11.46 Upper 6843.5 25-Year 93.50 19.01 21.99 2.64 2.25 0.002086 3.89 25.86 11.96 Upper 6843.5 50-Year 99.70 19.01 22.07 2.72 2.32 0.002136 4.02 26.84 12.20 Upper 6843.5 100-Year 105.00 19.01 22.13 2.79 2.38 0.002186 4.13 27.63 12.40 Upper 6831.5 2-Year 63.90 18.89 21.52 2.21 1.84 0.001802 3.16 20.84 11.57 Upper 6831.5 10-Year 84.60 18.89 21.85 2.54 2.11 0.001958 3.61 24.94 12.92 Upper 6831.5 25-Year 93.50 18.89 21.97 2.66 2.21 0.002052 3.81 26.51 14.40 Upper 6831.5 50-Year 99.70 18.89 22.05 2.74 2.28 0.002091 3.92 27.71 14.70 Upper 6831.5 100-Year 105.00 18.89 22.12 2.81 2.33 0.002132 4.02 28.67 14.91 Upper 6761.5 2-Year 63.90 18.81 21.32 1.99 1.60 0.002812 3.59 18.17 11.41 Upper 6761.5 10-Year 84.60 18.81 21.63 2.30 1.85 0.002971 4.06 22.51 16.07 Upper 6761.5 25-Year 93.50 18.81 21.74 2.41 1.94 0.003030 4.24 24.39 16.64 Upper 6761.5 50-Year 99.70 18.81 21.82 2.49 2.00 0.003071 4.36 25.71 17.60 Upper 6761.5 100-Year 105.00 18.81 21.88 2.55 2.05 0.003107 4.45 26.82 18.43 Upper 6736 2-Year 63.90 18.70 21.09 1.76 1.41 0.005350 4.56 14.95 14.90 Upper 6736 10-Year 84.60 18.70 21.43 2.10 1.68 0.004764 4.84 20.69 18.92 Upper 6736 25-Year 93.50 18.70 21.56 2.23 1.78 0.004612 4.95 23.28 23.85 Upper 6736 50-Year 99.70 18.70 21.65 2.33 1.86 0.004381 4.96 25.77 26.81 Upper 6736 100-Year 105.00 18.70 21.74 2.41 1.93 0.004144 4.94 28.11 28.24 Upper 6722 2-Year 63.90 18.23 20.52 1.44 1.11 0.016675 6.86 9.34 6.80 Upper 6722 10-Year 84.60 18.23 20.94 1.85 1.42 0.011892 6.81 13.73 12.55 Upper 6722 25-Year 93.50 18.23 21.06 1.97 1.51 0.011359 6.95 15.31 13.20 Upper 6722 50-Year 99.70 18.23 21.14 2.05 1.57 0.011167 7.06 16.32 13.59 Upper 6722 100-Year 105.00 18.23 21.21 2.12 1.62 0.010867 7.12 17.28 13.94 Upper 6600 Culvert Upper 5746 2-Year 63.90 15.40 18.62 2.52 2.32 0.001909 2.27 28.99 13.14 Upper 5746 10-Year 84.60 15.40 19.25 3.14 2.90 0.001544 2.37 37.68 14.64 Upper 5746 25-Year 93.50 15.40 19.71 3.60 3.32 0.001160 2.25 44.69 15.91 Upper 5746 50-Year 99.70 15.40 19.90 3.80 3.50 0.001088 2.26 47.87 16.40 Upper 5746 100-Year 105.00 15.40 20.16 4.05 3.73 0.000954 2.21 52.08 17.02 Upper 5737 2-Year 63.90 15.39 18.62 2.48 2.32 0.001564 2.06 33.15 17.90 Upper 5737 10-Year 84.60 15.39 19.25 3.11 2.92 0.001161 2.07 45.60 21.29 Upper 5737 25-Year 93.50 15.39 19.71 3.57 3.35 0.000824 1.91 56.04 23.77 Upper 5737 50-Year 99.70 15.39 19.91 3.77 3.54 0.000754 1.90 60.86 24.75 Upper 5737 100-Year 105.00 15.39 20.17 4.03 3.78 0.000643 1.83 67.28 25.96 Upper 5717 2-Year 63.90 15.32 18.60 2.53 2.38 0.001129 1.78 41.73 25.86 Upper 5717 10-Year 84.60 15.32 19.25 3.18 2.98 0.000761 1.70 59.64 29.57 Upper 5717 25-Year 93.50 15.32 19.72 3.65 3.42 0.000518 1.54 74.16 32.41 Upper 5717 50-Year 99.70 15.32 19.92 3.85 3.61 0.000468 1.51 80.74 33.45 Upper 5717 100-Year 105.00 15.32 20.17 4.10 3.85 0.000394 1.45 89.41 34.79 POST PROJECT HEC-RAS OUTPUT TABLE HEC-RAS Plan: PostNoBerm (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 5687 2-Year 63.90 15.24 18.57 2.58 2.42 0.001120 1.79 40.67 23.66 Upper 5687 10-Year 84.60 15.24 19.22 3.23 3.03 0.000786 1.75 57.57 33.37 Upper 5687 25-Year 93.50 15.24 19.70 3.71 3.48 0.000540 1.58 72.89 44.67 Upper 5687 50-Year 99.70 15.24 19.90 3.91 3.67 0.000458 1.51 86.58 47.74 Upper 5687 100-Year 105.00 15.24 20.16 4.17 3.91 0.000365 1.41 99.04 48.93 Upper 5655 2-Year 63.90 15.16 18.50 2.32 2.08 0.001887 2.10 34.44 25.07 Upper 5655 10-Year 84.60 15.16 19.19 3.00 2.69 0.001091 1.90 53.19 36.36 Upper 5655 25-Year 93.50 15.16 19.68 3.49 3.13 0.000684 1.66 68.96 42.85 Upper 5655 50-Year 99.70 15.16 19.88 3.70 3.32 0.000602 1.62 76.23 45.78 Upper 5655 100-Year 105.00 15.16 20.14 3.96 3.55 0.000490 1.53 86.03 49.37 Upper 5619 2-Year 63.90 15.06 18.46 2.65 2.48 0.001174 1.87 37.65 20.39 Upper 5619 10-Year 84.60 15.06 19.16 3.35 3.14 0.000734 1.73 65.66 51.59 Upper 5619 25-Year 93.50 15.06 19.67 3.86 3.62 0.000408 1.41 94.00 62.49 Upper 5619 50-Year 99.70 15.06 19.87 4.06 3.81 0.000345 1.35 107.10 68.62 Upper 5619 100-Year 105.00 15.06 20.14 4.33 4.06 0.000264 1.23 125.30 74.31 Upper 5579 2-Year 63.90 14.96 18.44 2.73 2.56 0.000721 1.49 63.04 73.91 Upper 5579 10-Year 84.60 14.96 19.16 3.45 3.24 0.000260 1.05 129.73 104.09 Upper 5579 25-Year 93.50 14.96 19.67 3.96 3.71 0.000122 0.79 183.24 107.49 Upper 5579 50-Year 99.70 14.96 19.88 4.17 3.91 0.000099 0.73 205.80 108.90 Upper 5579 100-Year 105.00 14.96 20.14 4.43 4.16 0.000074 0.66 234.72 110.67 Upper 5542 2-Year 63.90 14.86 18.42 2.81 2.63 0.000626 1.42 71.82 100.53 Upper 5542 10-Year 84.60 14.86 19.16 3.55 3.33 0.000173 0.87 163.79 132.15 Upper 5542 25-Year 93.50 14.86 19.67 4.06 3.81 0.000079 0.64 232.08 136.55 Upper 5542 50-Year 99.70 14.86 19.88 4.27 4.00 0.000063 0.60 260.82 138.50 Upper 5542 100-Year 105.00 14.86 20.14 4.53 4.25 0.000047 0.54 297.68 140.71 Upper 5519 2-Year 63.90 14.80 18.41 2.86 2.68 0.000452 1.22 89.66 122.31 Upper 5519 10-Year 84.60 14.80 19.16 3.61 3.38 0.000122 0.74 189.90 140.85 Upper 5519 25-Year 93.50 14.80 19.67 4.12 3.86 0.000059 0.56 264.16 150.59 Upper 5519 50-Year 99.70 14.80 19.88 4.33 4.06 0.000048 0.52 296.06 154.29 Upper 5519 100-Year 105.00 14.80 20.14 4.59 4.31 0.000036 0.47 337.27 157.23 Upper 5484 2-Year 63.90 14.71 18.39 2.93 2.75 0.000236 0.90 126.26 144.14 Upper 5484 10-Year 84.60 14.71 19.15 3.69 3.46 0.000069 0.57 238.49 152.20 Upper 5484 25-Year 93.50 14.71 19.66 4.20 3.94 0.000036 0.44 317.96 158.07 Upper 5484 50-Year 99.70 14.71 19.87 4.41 4.14 0.000030 0.42 351.38 161.04 Upper 5484 100-Year 105.00 14.71 20.14 4.68 4.39 0.000024 0.39 394.72 166.44 Upper 5445 2-Year 63.90 14.60 18.39 2.87 2.79 0.000110 0.62 171.24 169.07 Upper 5445 10-Year 84.60 14.60 19.15 3.63 3.52 0.000038 0.42 304.98 181.40 Upper 5445 25-Year 93.50 14.60 19.66 4.15 4.02 0.000021 0.34 399.34 186.29 Upper 5445 50-Year 99.70 14.60 19.87 4.36 4.22 0.000018 0.33 438.63 188.30 Upper 5445 100-Year 105.00 14.60 20.14 4.62 4.48 0.000014 0.30 488.82 190.46 Upper 5379 2-Year 63.90 14.43 18.38 3.21 3.06 0.000089 0.59 183.09 163.72 Upper 5379 10-Year 84.60 14.43 19.15 3.97 3.79 0.000034 0.42 311.50 172.36 Upper 5379 25-Year 93.50 14.43 19.66 4.49 4.28 0.000020 0.35 401.53 178.02 Upper 5379 50-Year 99.70 14.43 19.87 4.70 4.48 0.000017 0.33 439.18 180.63 Upper 5379 100-Year 105.00 14.43 20.14 4.96 4.74 0.000014 0.31 487.47 183.27 Upper 5313 2-Year 63.90 14.25 18.38 3.38 3.17 0.000051 0.46 222.15 159.12 Upper 5313 10-Year 84.60 14.25 19.15 4.15 3.89 0.000023 0.36 345.08 161.96 Upper 5313 25-Year 93.50 14.25 19.66 4.66 4.37 0.000014 0.30 428.95 163.82 Upper 5313 50-Year 99.70 14.25 19.87 4.87 4.57 0.000013 0.29 463.44 164.58 Upper 5313 100-Year 105.00 14.25 20.14 5.14 4.82 0.000011 0.28 507.22 165.55 Upper 5265 2-Year 63.90 14.13 18.38 3.50 3.28 0.000040 0.41 247.12 165.77 Upper 5265 10-Year 84.60 14.13 19.14 4.26 4.00 0.000019 0.33 375.79 169.90 Upper 5265 25-Year 93.50 14.13 19.66 4.78 4.48 0.000012 0.28 464.05 172.73 Upper 5265 50-Year 99.70 14.13 19.87 4.99 4.68 0.000011 0.27 500.47 173.86 Upper 5265 100-Year 105.00 14.13 20.14 5.26 4.93 0.000009 0.26 546.78 175.26 Upper 5146 2-Year 63.90 13.81 18.38 3.82 3.58 0.000013 0.25 375.72 197.00 Upper 5146 10-Year 84.60 13.81 19.14 4.58 4.30 0.000008 0.22 528.85 201.93 Upper 5146 25-Year 93.50 13.81 19.66 5.10 4.78 0.000005 0.20 633.75 204.97 Upper 5146 50-Year 99.70 13.81 19.87 5.31 4.98 0.000005 0.19 676.97 206.22 Upper 5146 100-Year 105.00 13.81 20.13 5.57 5.23 0.000004 0.19 731.91 207.80 Upper 5012 2-Year 63.90 13.46 18.37 4.16 3.91 0.000006 0.18 538.74 262.78 Upper 5012 10-Year 84.60 13.46 19.14 4.93 4.63 0.000004 0.16 742.46 267.36 Upper 5012 25-Year 93.50 13.46 19.66 5.45 5.11 0.000003 0.14 881.06 270.10 Upper 5012 50-Year 99.70 13.46 19.87 5.66 5.31 0.000002 0.14 937.97 271.22 Upper 5012 100-Year 105.00 13.46 20.13 5.92 5.56 0.000002 0.14 1010.16 272.63 HEC-RAS Plan: PostNoBerm (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 4909 2-Year 63.90 13.19 18.37 4.43 4.16 0.000003 0.13 692.39 299.48 Upper 4909 10-Year 84.60 13.19 19.14 5.20 4.88 0.000002 0.13 924.97 306.14 Upper 4909 25-Year 93.50 13.19 19.66 5.72 5.36 0.000002 0.11 1084.05 310.61 Upper 4909 50-Year 99.70 13.19 19.87 5.93 5.56 0.000001 0.11 1149.55 312.43 Upper 4909 100-Year 105.00 13.19 20.13 6.19 5.81 0.000001 0.11 1232.76 314.00 Upper 4817 2-Year 63.90 12.95 18.37 4.66 4.37 0.000003 0.13 765.59 333.63 Upper 4817 10-Year 84.60 12.95 19.14 5.43 5.09 0.000002 0.12 1029.74 354.11 Upper 4817 25-Year 93.50 12.95 19.66 5.94 5.58 0.000001 0.11 1215.97 367.86 Upper 4817 50-Year 99.70 12.95 19.87 6.15 5.77 0.000001 0.11 1293.91 373.47 Upper 4817 100-Year 105.00 12.95 20.13 6.42 6.02 0.000001 0.10 1393.82 377.70 Upper 4711 2-Year 63.90 12.67 18.37 4.95 4.65 0.000003 0.13 733.12 320.09 Upper 4711 10-Year 84.60 12.67 19.14 5.72 5.37 0.000002 0.13 987.59 342.37 Upper 4711 25-Year 93.50 12.67 19.66 6.24 5.85 0.000001 0.12 1168.10 357.34 Upper 4711 50-Year 99.70 12.67 19.87 6.45 6.05 0.000001 0.11 1243.87 363.43 Upper 4711 100-Year 105.00 12.67 20.13 6.71 6.30 0.000001 0.11 1341.24 368.67 Upper 4619 2-Year 63.90 12.42 18.37 5.20 4.88 0.000004 0.17 636.88 311.46 Upper 4619 10-Year 84.60 12.42 19.14 5.97 5.60 0.000003 0.15 883.76 331.15 Upper 4619 25-Year 93.50 12.42 19.66 6.49 6.09 0.000002 0.14 1058.06 344.38 Upper 4619 50-Year 99.70 12.42 19.87 6.70 6.28 0.000002 0.13 1131.04 349.77 Upper 4619 100-Year 105.00 12.42 20.13 6.96 6.53 0.000002 0.13 1224.73 355.16 Upper 4541 2-Year 63.90 12.22 18.37 5.40 5.06 0.000063 0.69 117.76 268.45 Upper 4541 10-Year 84.60 12.22 19.13 6.16 5.78 0.000056 0.72 149.88 270.09 Upper 4541 25-Year 93.50 12.22 19.65 6.68 6.27 0.000046 0.68 171.49 271.19 Upper 4541 50-Year 99.70 12.22 19.86 6.89 6.47 0.000045 0.69 180.27 271.63 Upper 4541 100-Year 105.00 12.22 20.13 7.16 6.72 0.000041 0.68 191.38 272.20 Proposed Wetland 53 2-Year 15.74 16.79 18.36 1.47 1.47 0.000069 0.53 29.60 278.59 Proposed Wetland 53 10-Year 36.73 16.79 19.14 2.25 2.25 0.000091 0.81 45.42 281.84 Proposed Wetland 53 25-Year 52.87 16.79 19.64 2.75 2.75 0.000096 0.95 55.49 283.87 Proposed Wetland 53 50-Year 59.92 16.79 19.85 2.95 2.95 0.000097 1.00 59.65 284.73 Proposed Wetland 53 100-Year 69.19 16.79 20.11 3.22 3.22 0.000097 1.06 65.03 285.85 Proposed Wetland 48 2-Year 15.74 16.97 18.34 1.36 1.36 0.000348 1.13 13.87 274.94 Proposed Wetland 48 10-Year 36.73 16.97 19.10 2.12 2.12 0.000431 1.70 21.64 278.02 Proposed Wetland 48 25-Year 52.87 16.97 19.59 2.61 2.61 0.000450 1.99 26.58 279.97 Proposed Wetland 48 50-Year 59.92 16.97 19.79 2.81 2.81 0.000451 2.09 28.63 280.80 Proposed Wetland 48 100-Year 69.19 16.97 20.05 3.07 3.07 0.000448 2.21 31.28 281.85 Proposed Wetland 10 Culvert Proposed Wetland 8 2-Year 15.74 17.00 17.31 0.29 0.29 0.020041 3.09 5.09 17.31 Proposed Wetland 8 10-Year 36.73 17.00 17.54 0.49 0.48 0.016889 3.97 9.25 18.92 Proposed Wetland 8 25-Year 52.87 17.00 17.68 0.60 0.59 0.015957 4.42 11.95 19.90 Proposed Wetland 8 50-Year 59.92 17.00 17.74 0.64 0.64 0.015587 4.58 13.08 20.30 Proposed Wetland 8 100-Year 69.19 17.00 18.67 1.30 1.28 0.001151 1.98 34.95 26.82 Proposed Wetland 3 2-Year 15.74 17.00 17.16 0.16 0.16 0.024732 2.25 6.99 44.78 Proposed Wetland 3 10-Year 36.73 17.00 17.28 0.27 0.27 0.020247 2.96 12.40 45.29 Proposed Wetland 3 25-Year 52.87 17.00 17.60 0.58 0.58 0.003188 1.94 27.23 46.65 Proposed Wetland 3 50-Year 59.92 17.00 17.80 0.77 0.76 0.001564 1.64 36.65 47.50 Proposed Wetland 3 100-Year 69.19 17.00 18.70 1.58 1.54 0.000166 0.85 81.11 51.30 Lower 3016 2-Year 65.26 11.67 18.36 5.99 5.52 0.000021 0.71 140.94 55.61 Lower 3016 10-Year 72.27 11.67 19.13 6.76 6.23 0.000015 0.65 173.11 61.20 Lower 3016 25-Year 70.13 11.67 19.65 7.28 6.70 0.000010 0.56 194.88 64.94 Lower 3016 50-Year 73.08 11.67 19.86 7.49 6.90 0.000010 0.56 203.72 66.48 Lower 3016 100-Year 73.81 11.67 20.13 7.75 7.14 0.000008 0.53 214.90 68.42 Lower 3003 2-Year 65.26 11.67 18.36 5.94 5.57 0.000025 0.77 98.39 54.35 Lower 3003 10-Year 72.27 11.67 19.13 6.71 6.29 0.000020 0.75 112.63 56.99 Lower 3003 25-Year 70.13 11.67 19.65 7.23 6.78 0.000014 0.67 122.23 58.77 Lower 3003 50-Year 73.08 11.67 19.86 7.44 6.98 0.000014 0.68 126.12 59.49 Lower 3003 100-Year 73.81 11.67 20.12 7.70 7.23 0.000013 0.66 131.04 60.41 Lower 2800 Culvert Lower 2788 2-Year 65.26 11.13 18.32 7.04 3.92 0.000003 0.54 121.20 17.23 Lower 2788 10-Year 72.27 11.13 19.08 7.76 4.14 0.000003 0.54 134.31 17.31 Lower 2788 25-Year 70.13 11.13 19.60 8.26 4.28 0.000002 0.49 143.34 17.36 Lower 2788 50-Year 73.08 11.13 19.80 8.45 4.34 0.000002 0.50 146.91 17.38 Lower 2788 100-Year 73.81 11.13 20.07 8.71 4.40 0.000002 0.49 151.52 17.41 Lower 2771 2-Year 65.26 11.13 18.27 6.69 1.98 0.000076 1.70 38.30 5.72 Lower 2771 10-Year 72.27 11.13 19.03 7.36 2.05 0.000072 1.69 42.67 5.80 Lower 2771 25-Year 70.13 11.13 19.56 7.82 2.09 0.000057 1.53 45.76 5.85 FLOWS TO PANTHER CREEK WETLAND 100-YR WSE UPSTREAM OF CUVERT 76 AND 100-YR FLOW TO CITY OF RENTON SYSTEM HEC-RAS Plan: PostNoBerm (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Lower 2771 50-Year 73.08 11.13 19.77 7.99 2.11 0.000059 1.56 46.96 5.87 Lower 2771 100-Year 73.81 11.13 20.03 8.22 2.13 0.000055 1.52 48.53 5.90 Lower 2720 Culvert Lower 2716 2-Year 65.26 10.88 17.36 6.11 1.92 0.000098 1.89 34.46 5.64 Lower 2716 10-Year 72.27 10.88 17.91 6.60 1.97 0.000098 1.92 37.57 5.69 Lower 2716 25-Year 70.13 10.88 18.50 7.12 2.02 0.000075 1.71 40.96 5.75 Lower 2716 50-Year 73.08 10.88 18.61 7.22 2.03 0.000078 1.76 41.61 5.76 Lower 2716 100-Year 73.81 10.88 18.85 7.43 2.05 0.000074 1.72 43.01 5.79 Lower 2708 2-Year 95.54 11.04 17.28 5.89 1.89 0.000231 2.88 33.13 5.63 Lower 2708 10-Year 87.19 11.04 17.87 6.42 1.95 0.000152 2.39 36.49 5.69 Lower 2708 25-Year 85.30 11.04 18.47 6.95 2.01 0.000117 2.14 39.92 5.75 Lower 2708 50-Year 85.40 11.04 18.59 7.05 2.02 0.000113 2.10 40.60 5.76 Lower 2708 100-Year 84.54 11.04 18.83 7.27 2.04 0.000102 2.01 42.02 5.78 Lower 2550 Culvert Lower 2543 2-Year 95.54 10.80 16.89 5.77 1.88 0.000247 2.96 32.28 5.60 Lower 2543 10-Year 87.19 10.80 17.54 6.35 1.94 0.000158 2.43 35.94 5.66 Lower 2543 25-Year 85.30 10.80 18.15 6.89 2.00 0.000122 2.17 39.39 5.72 Lower 2543 50-Year 85.40 10.80 18.26 6.99 2.01 0.000117 2.13 40.05 5.73 Lower 2543 100-Year 84.54 10.80 18.52 7.21 2.03 0.000105 2.04 41.49 5.76 Lower 2539 2-Year 95.54 10.80 16.89 5.77 1.88 0.000247 2.96 32.27 5.60 Lower 2539 10-Year 87.19 10.80 17.54 6.35 1.94 0.000158 2.43 35.93 5.66 Lower 2539 25-Year 85.30 10.80 18.15 6.89 2.00 0.000122 2.17 39.39 5.72 Lower 2539 50-Year 85.40 10.80 18.26 6.99 2.01 0.000117 2.13 40.05 5.73 Lower 2539 100-Year 84.54 10.80 18.51 7.21 2.03 0.000105 2.04 41.49 5.76 Lower 2500 Culvert Lower 2203 2-Year 95.54 10.29 16.32 5.72 1.87 0.000256 3.00 31.85 5.56 Lower 2203 10-Year 87.19 10.29 17.06 6.39 1.94 0.000159 2.42 35.96 5.63 Lower 2203 25-Year 85.30 10.29 17.68 6.94 2.00 0.000121 2.16 39.48 5.69 Lower 2203 50-Year 85.40 10.29 17.79 7.04 2.00 0.000117 2.13 40.12 5.70 Lower 2203 100-Year 84.54 10.29 18.05 7.27 2.03 0.000105 2.03 41.60 5.72 Lower 2199 2-Year 95.54 10.29 16.32 5.72 1.87 0.000256 3.00 31.83 5.56 Lower 2199 10-Year 87.19 10.29 17.05 6.38 1.94 0.000159 2.42 35.96 5.63 Lower 2199 25-Year 85.30 10.29 17.68 6.94 1.99 0.000121 2.16 39.47 5.69 Lower 2199 50-Year 85.40 10.29 17.79 7.04 2.00 0.000117 2.13 40.12 5.70 Lower 2199 100-Year 84.54 10.29 18.05 7.27 2.03 0.000105 2.03 41.59 5.72 Lower 2100 Culvert Lower 2030 2-Year 95.54 9.94 15.87 5.64 1.85 0.000268 3.06 31.25 5.54 Lower 2030 10-Year 87.19 9.94 16.67 6.37 1.93 0.000162 2.44 35.70 5.61 Lower 2030 25-Year 85.30 9.94 17.30 6.93 1.99 0.000123 2.17 39.26 5.67 Lower 2030 50-Year 85.40 9.94 17.41 7.03 2.00 0.000119 2.14 39.88 5.68 Lower 2030 100-Year 84.54 9.94 17.68 7.26 2.02 0.000107 2.04 41.38 5.70 Lower 2026 2-Year 95.54 9.94 15.87 5.64 1.85 0.000268 3.06 31.24 5.54 Lower 2026 10-Year 87.19 9.94 16.67 6.36 1.93 0.000162 2.44 35.70 5.61 Lower 2026 25-Year 85.30 9.94 17.30 6.93 1.99 0.000123 2.17 39.25 5.67 Lower 2026 50-Year 85.40 9.94 17.41 7.03 2.00 0.000119 2.14 39.88 5.68 Lower 2026 100-Year 84.54 9.94 17.67 7.26 2.02 0.000107 2.04 41.38 5.70 Lower 2000 Culvert Lower 1497 2-Year 95.54 9.14 15.09 5.68 1.85 0.000269 3.06 31.23 5.50 Lower 1497 10-Year 87.19 9.14 16.00 6.51 1.94 0.000156 2.40 36.31 5.58 Lower 1497 25-Year 85.30 9.14 16.66 7.09 1.99 0.000118 2.13 39.96 5.63 Lower 1497 50-Year 85.40 9.14 16.76 7.19 2.00 0.000115 2.11 40.57 5.64 Lower 1497 100-Year 84.54 9.14 17.04 7.43 2.02 0.000103 2.01 42.12 5.67 Lower 1493 2-Year 95.54 9.14 15.09 5.67 1.85 0.000270 3.06 31.22 5.50 Lower 1493 10-Year 87.19 9.14 16.00 6.51 1.94 0.000156 2.40 36.30 5.58 Lower 1493 25-Year 85.30 9.14 16.65 7.09 1.99 0.000118 2.13 39.95 5.63 Lower 1493 50-Year 85.40 9.14 16.76 7.19 2.00 0.000115 2.11 40.56 5.64 Lower 1493 100-Year 84.54 9.14 17.04 7.43 2.02 0.000103 2.01 42.11 5.67 Lower 1400 Culvert Lower 1001 2-Year 95.54 8.48 14.41 5.67 1.84 0.000273 3.08 31.06 5.47 Lower 1001 10-Year 87.19 8.48 15.43 6.60 1.94 0.000153 2.38 36.66 5.55 Lower 1001 25-Year 85.30 8.48 16.10 7.20 2.00 0.000116 2.11 40.39 5.61 Lower 1001 50-Year 85.40 8.48 16.20 7.30 2.00 0.000112 2.08 40.98 5.62 FLOW ARE REDUCED DURING HIGHER EVENTS BY FLOW SPLIT HYDRAULICS HEC-RAS Plan: PostNoBerm (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Lower 1001 100-Year 84.54 8.48 16.48 7.55 2.03 0.000100 1.99 42.58 5.64 Lower 997 2-Year 95.54 8.48 14.41 5.67 1.84 0.000274 3.08 31.05 5.47 Lower 997 10-Year 87.19 8.48 15.43 6.60 1.94 0.000153 2.38 36.65 5.55 Lower 997 25-Year 85.30 8.48 16.09 7.20 2.00 0.000116 2.11 40.39 5.61 Lower 997 50-Year 85.40 8.48 16.20 7.30 2.00 0.000112 2.08 40.98 5.62 Lower 997 100-Year 84.54 8.48 16.48 7.55 2.03 0.000100 1.99 42.57 5.64 Lower 900 Culvert Lower 490 2-Year 95.54 7.72 13.66 5.69 1.84 0.000275 3.08 31.00 5.45 Lower 490 10-Year 87.19 7.72 14.78 6.72 1.94 0.000148 2.35 37.18 5.53 Lower 490 25-Year 85.30 7.72 15.47 7.34 2.00 0.000112 2.08 41.01 5.58 Lower 490 50-Year 85.40 7.72 15.57 7.44 2.01 0.000109 2.05 41.58 5.59 Lower 490 100-Year 84.54 7.72 15.87 7.70 2.03 0.000097 1.96 43.23 5.61 Lower 486 2-Year 95.54 7.72 13.65 5.69 1.84 0.000276 3.08 30.99 5.45 Lower 486 10-Year 87.19 7.72 14.78 6.72 1.94 0.000148 2.35 37.17 5.53 Lower 486 25-Year 85.30 7.72 15.47 7.34 2.00 0.000112 2.08 41.00 5.58 Lower 486 50-Year 85.40 7.72 15.57 7.44 2.01 0.000109 2.05 41.58 5.59 Lower 486 100-Year 84.54 7.72 15.86 7.70 2.03 0.000097 1.96 43.22 5.61 Lower 450 Culvert Lower 427.3552 2-Year 95.54 7.50 13.48 5.03 4.89 0.000025 0.72 161.88 45.84 Lower 427.3552 10-Year 87.19 7.50 14.59 6.14 5.98 0.000010 0.52 216.89 52.54 Lower 427.3552 25-Year 85.30 7.50 15.28 6.83 6.65 0.000007 0.45 254.15 56.63 Lower 427.3552 50-Year 85.40 7.50 15.38 6.93 6.75 0.000006 0.44 259.89 57.24 Lower 427.3552 100-Year 84.54 7.50 15.67 7.22 7.03 0.000005 0.42 276.87 58.99 Lower 370.2063 2-Year 95.54 7.50 13.47 5.02 4.89 0.000025 0.72 162.04 45.96 Lower 370.2063 10-Year 87.19 7.50 14.59 6.14 5.98 0.000010 0.52 217.26 52.71 Lower 370.2063 25-Year 85.30 7.50 15.28 6.83 6.65 0.000007 0.45 254.66 56.83 Lower 370.2063 50-Year 85.40 7.50 15.38 6.93 6.75 0.000006 0.44 260.42 57.44 Lower 370.2063 100-Year 84.54 7.50 15.67 7.22 7.03 0.000005 0.42 277.47 59.20 Lower 106.7341 2-Year 95.54 7.30 13.47 5.14 4.99 0.000024 0.70 164.63 45.79 Lower 106.7341 10-Year 87.19 7.30 14.59 6.27 6.08 0.000010 0.51 219.83 52.52 Lower 106.7341 25-Year 85.30 7.30 15.28 6.95 6.74 0.000006 0.44 257.13 56.62 Lower 106.7341 50-Year 85.40 7.30 15.38 7.05 6.84 0.000006 0.44 262.88 57.22 Lower 106.7341 100-Year 84.54 7.30 15.67 7.34 7.12 0.000005 0.41 279.88 58.98 Lower 86.6344 2-Year 95.54 7.30 13.47 5.25 5.08 0.000022 0.69 167.31 45.79 Lower 86.6344 10-Year 87.19 7.30 14.59 6.37 6.16 0.000009 0.50 222.52 52.52 Lower 86.6344 25-Year 85.30 7.30 15.28 7.06 6.83 0.000006 0.44 259.83 56.62 Lower 86.6344 50-Year 85.40 7.30 15.38 7.16 6.92 0.000006 0.43 265.57 57.22 Lower 86.6344 100-Year 84.54 7.30 15.67 7.45 7.21 0.000005 0.41 282.57 58.98 Lower 50 Culvert Lower 0.0000 2-Year 95.54 5.00 13.00 6.10 5.53 0.000015 0.61 179.47 42.98 Lower 0.0000 10-Year 87.19 5.00 14.20 7.30 6.62 0.000007 0.45 235.36 50.17 Lower 0.0000 25-Year 85.30 5.00 14.90 8.00 7.26 0.000005 0.40 271.95 54.37 Lower 0.0000 50-Year 85.40 5.00 15.00 8.10 7.35 0.000004 0.39 277.42 54.97 Lower 0.0000 100-Year 84.54 5.00 15.30 8.40 7.62 0.000004 0.37 294.18 56.77 01000200030004000500060005101520253035DCRollingHillsREV Geom: FutureDaylightNoBerm Flow: Proposed_Future_OpenMain Channel Distance (ft)Elevation (ft)LegendWS 100-YearGroundRollingHills UpperFUTURE POTENTIAL DAYLIGHT TO SPRINGBROOK CREEK HEC-RAS PROFILECULVERT 76 EXTENDED ACROSS EAST VALLEY ROADSPRINGBROOK CREEK 100-YR CLEARANCE 2.67 FEET HEC-RAS Plan: FutOC River: RollingHills Reach: Upper Profile: 100-Year Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 7155 100-Year 105.00 20.15 23.19 2.69 2.18 0.002825 4.43 24.85 11.43 Upper 7082 100-Year 105.00 19.56 22.71 2.77 2.09 0.004925 5.68 20.58 12.34 Upper 7019 100-Year 105.00 19.67 22.63 2.59 2.08 0.002781 4.26 26.30 14.34 Upper 6998 100-Year 105.00 19.52 22.54 2.71 2.22 0.002907 4.54 26.04 14.86 Upper 6869.5 100-Year 105.00 19.20 22.17 2.69 2.16 0.002923 4.47 26.03 14.20 Upper 6843.5 100-Year 105.00 19.01 22.13 2.79 2.38 0.002185 4.13 27.63 12.40 Upper 6831.5 100-Year 105.00 18.89 22.12 2.81 2.33 0.002131 4.02 28.67 14.91 Upper 6761.5 100-Year 105.00 18.81 21.88 2.55 2.05 0.003107 4.45 26.83 18.43 Upper 6736 100-Year 105.00 18.70 21.74 2.41 1.93 0.004142 4.94 28.12 28.24 Upper 6722 100-Year 105.00 18.23 21.21 2.12 1.62 0.010881 7.13 17.27 13.94 Upper 6600 Culvert Upper 5746 100-Year 105.00 15.40 18.83 2.73 2.52 0.003893 3.43 31.84 13.65 Upper 5737 100-Year 105.00 15.39 18.83 2.69 2.52 0.003107 3.07 37.10 19.04 Upper 5717 100-Year 105.00 15.32 18.81 2.74 2.57 0.002191 2.61 47.23 27.05 Upper 5687 100-Year 105.00 15.24 18.73 2.74 2.57 0.002353 2.71 44.63 24.53 Upper 5655 100-Year 105.00 15.16 18.57 2.39 2.14 0.004497 3.31 36.20 25.51 Upper 5619 100-Year 105.00 15.06 18.45 2.64 2.47 0.003219 3.08 37.43 20.33 Upper 5579 100-Year 105.00 14.96 18.38 2.67 2.51 0.002215 2.58 58.85 70.34 Upper 5542 100-Year 105.00 14.86 18.29 2.68 2.51 0.002386 2.68 59.19 92.79 Upper 5519 100-Year 105.00 14.80 18.26 2.71 2.54 0.001786 2.34 72.50 103.43 Upper 5484 100-Year 105.00 14.71 18.07 2.61 2.45 0.002891 2.90 46.42 127.55 Upper 5445 100-Year 105.00 14.60 18.04 2.52 2.44 0.001328 1.97 72.84 159.88 Upper 5379 100-Year 105.00 14.43 17.86 2.68 2.56 0.002450 2.75 42.56 120.40 Upper 5313 100-Year 105.00 14.25 17.66 2.66 2.50 0.002967 2.98 39.46 127.27 Upper 5265 100-Year 105.00 14.13 17.52 2.64 2.48 0.002988 2.97 39.88 135.67 Upper 5146 100-Year 105.00 13.81 17.09 2.53 2.37 0.003778 3.25 35.22 164.20 Upper 5012 100-Year 105.00 13.46 17.02 2.81 2.64 0.000600 1.39 121.02 221.32 Upper 4909 100-Year 105.00 13.19 16.81 2.87 2.69 0.002318 2.77 43.02 261.39 Upper 4817 100-Year 105.00 12.95 16.60 2.89 2.71 0.002228 2.73 43.02 254.14 Upper 4711 100-Year 105.00 12.67 16.38 2.96 2.78 0.002072 2.67 44.12 232.73 Upper 4619 100-Year 105.00 12.42 16.22 3.05 2.86 0.001692 2.46 59.75 142.80 Upper 4541 100-Year 105.00 12.22 16.08 3.11 2.92 0.001693 2.50 47.75 23.17 Upper 3016 100-Year 143.00 11.67 15.77 3.39 3.13 0.001078 3.48 51.39 25.22 Upper 3003 100-Year 143.00 11.67 15.77 3.35 3.14 0.000935 3.25 50.50 26.26 Upper 2800 Culvert Upper 2650 100-Year 143.00 10.69 15.44 3.01 2.82 0.000013 0.36 931.83 623.82 Upper 2203 100-Year 143.00 10.01 15.43 3.38 3.15 0.000012 0.37 944.00 625.15 Upper 2030 100-Year 143.00 9.70 15.43 3.36 3.21 0.000010 0.34 963.98 625.76 Upper 1497 100-Year 143.00 8.99 15.39 3.60 3.28 0.000151 1.34 106.47 29.59 Upper 1001 100-Year 143.00 8.41 15.34 3.87 3.52 0.000103 1.16 122.75 31.72 Upper 490 100-Year 143.00 7.73 15.30 4.20 3.82 0.000067 0.99 143.95 34.29 Upper 427.3552 100-Year 143.00 7.50 15.31 6.86 6.68 0.000017 0.72 255.74 56.80 Upper 370.2063 100-Year 143.00 7.50 15.30 6.85 6.67 0.000017 0.72 256.22 57.00 Upper 106.7341 100-Year 143.00 7.30 15.30 6.97 6.76 0.000016 0.71 258.54 56.77 Upper 86.6344 100-Year 143.00 7.30 15.30 7.08 6.85 0.000016 0.70 261.23 56.77 Upper 0.0000 100-Year 143.00 5.00 15.30 8.40 7.62 0.000010 0.61 294.18 56.77 FUTURE POTENTIAL DAYLIGHT TO SPRINGBROOK CREEK HEC-RAS OUTPUT TABLE WS ELEVATION USED TO CALCULATE CLEARANCE USED FOR MODIFIED SHIELD'S STREAMBED SIZING, SCOUR AND ROCK FOR CULVERT END 01000200030004000500060005101520253035DCRollingHillsREV Geom: FutureDaylightNoBerm Flow: Proposed_Future_LowMain Channel Distance (ft)Elevation (ft)LegendWS MarWS OctGroundRollingHills UpperSPRINGBROOKCREEKCULVERT 76AVERAGEDEPTH ATCENTER OFCHANNEL 0.8FTFUTURE DAYLIGHT TO SPRINGBROOKOCTOBER AND MARCH MEAN FLOWS HEC-RAS Plan: PPMonth River: RollingHills Reach: Upper Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 7155 Oct 0.54 20.15 20.29 0.07 0.07 0.035120 1.56 0.35 5.00 Upper 7155 Mar 0.56 20.15 20.29 0.07 0.07 0.036135 1.59 0.35 5.04 Upper 7082 Oct 0.54 19.56 19.97 0.24 0.24 0.000664 0.49 1.11 4.54 Upper 7082 Mar 0.56 19.56 19.97 0.25 0.24 0.000675 0.50 1.13 4.57 Upper 7019 Oct 0.54 19.67 19.88 0.13 0.13 0.003632 0.76 0.71 5.41 Upper 7019 Mar 0.56 19.67 19.88 0.13 0.13 0.003643 0.77 0.73 5.50 Upper 6998 Oct 0.54 19.52 19.82 0.15 0.15 0.002324 0.68 0.80 5.21 Upper 6998 Mar 0.56 19.52 19.82 0.16 0.15 0.002343 0.69 0.82 5.24 Upper 6869.5 Oct 0.54 19.20 19.36 0.12 0.12 0.006127 0.94 0.58 4.73 Upper 6869.5 Mar 0.56 19.20 19.36 0.12 0.12 0.006101 0.95 0.59 4.77 Upper 6843.5 Oct 0.54 19.01 19.25 0.14 0.13 0.003574 0.78 0.70 5.04 Upper 6843.5 Mar 0.56 19.01 19.25 0.14 0.14 0.003523 0.78 0.72 5.10 Upper 6831.5 Oct 0.54 18.89 19.22 0.16 0.15 0.001573 0.56 0.96 6.14 Upper 6831.5 Mar 0.56 18.89 19.23 0.16 0.16 0.001555 0.57 0.99 6.21 Upper 6761.5 Oct 0.54 18.81 19.09 0.17 0.17 0.002287 0.72 0.75 4.39 Upper 6761.5 Mar 0.56 18.81 19.09 0.17 0.17 0.002474 0.75 0.75 4.38 Upper 6736 Oct 0.54 18.70 18.93 0.11 0.11 0.017927 1.51 0.36 3.24 Upper 6736 Mar 0.56 18.70 18.94 0.11 0.11 0.017969 1.53 0.37 3.26 Upper 6722 Oct 0.54 18.23 18.57 0.16 0.14 0.028495 2.27 0.24 1.47 Upper 6722 Mar 0.56 18.23 18.57 0.16 0.14 0.028327 2.29 0.24 1.49 Upper 6600 Culvert Upper 5746 Oct 0.54 15.40 15.82 0.21 0.21 0.002441 0.51 1.05 5.03 Upper 5746 Mar 0.56 15.40 15.82 0.21 0.21 0.002441 0.52 1.08 5.09 Upper 5737 Oct 0.54 15.39 15.79 0.20 0.20 0.002983 0.55 0.98 4.84 Upper 5737 Mar 0.56 15.39 15.80 0.20 0.20 0.002973 0.56 1.00 4.91 Upper 5717 Oct 0.54 15.32 15.74 0.21 0.21 0.002341 0.51 1.07 5.07 Upper 5717 Mar 0.56 15.32 15.75 0.21 0.21 0.002338 0.51 1.10 5.14 Upper 5687 Oct 0.54 15.24 15.68 0.22 0.22 0.001883 0.47 1.16 5.28 Upper 5687 Mar 0.56 15.24 15.69 0.22 0.22 0.001885 0.47 1.19 5.35 Upper 5655 Oct 0.54 15.16 15.59 0.21 0.21 0.004269 0.68 0.79 3.68 Upper 5655 Mar 0.56 15.16 15.60 0.22 0.21 0.004271 0.69 0.81 3.73 Upper 5619 Oct 0.54 15.06 15.48 0.21 0.20 0.002551 0.52 1.04 4.98 Upper 5619 Mar 0.56 15.06 15.48 0.21 0.21 0.002547 0.53 1.06 5.05 Upper 5579 Oct 0.54 14.96 15.37 0.20 0.20 0.002766 0.54 1.00 4.91 Upper 5579 Mar 0.56 14.96 15.37 0.21 0.20 0.002766 0.54 1.03 4.98 Upper 5542 Oct 0.54 14.86 15.27 0.21 0.20 0.002574 0.52 1.03 4.98 Upper 5542 Mar 0.56 14.86 15.28 0.21 0.21 0.002562 0.53 1.06 5.05 Upper 5519 Oct 0.54 14.80 15.21 0.21 0.20 0.002585 0.52 1.03 4.97 Upper 5519 Mar 0.56 14.80 15.22 0.21 0.21 0.002611 0.53 1.05 5.03 Upper 5484 Oct 0.54 14.71 15.12 0.21 0.20 0.002699 0.53 1.01 4.93 Upper 5484 Mar 0.56 14.71 15.13 0.21 0.21 0.002542 0.53 1.07 5.06 Upper 5445 Oct 0.54 14.60 15.02 0.21 0.21 0.002437 0.51 1.05 5.03 Upper 5445 Mar 0.56 14.60 15.05 0.22 0.22 0.001882 0.47 1.19 5.35 Upper 5379 Oct 0.54 14.43 14.91 0.24 0.24 0.001175 0.39 1.38 5.76 Upper 5379 Mar 0.56 14.43 14.99 0.30 0.29 0.000542 0.30 1.85 6.25 Upper 5313 Oct 0.54 14.25 14.88 0.36 0.35 0.000252 0.23 2.32 6.52 Upper 5313 Mar 0.56 14.25 14.97 0.42 0.41 0.000135 0.19 2.93 6.88 Upper 5265 Oct 2.13 14.13 14.81 0.39 0.38 0.002616 0.80 2.65 6.72 Upper 5265 Mar 2.97 14.13 14.91 0.46 0.45 0.002646 0.90 3.30 7.10 Upper 5146 Oct 2.13 13.81 14.49 0.40 0.39 0.002551 0.80 2.67 6.74 Upper 5146 Mar 2.97 13.81 14.59 0.47 0.46 0.002562 0.89 3.34 7.12 FUTURE DAYLIGHT TO SPRINGBROOK CREEK OCTOBER AND MARCH HEC-RAS OUTPUT TABLE HEC-RAS Plan: PPMonth River: RollingHills Reach: Upper (Continued) Reach River Sta Profile Q Total Min Ch El W.S. Elev Hydr Depth C Hydr Radius C E.G. Slope Vel Chnl Flow Area Top Width (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Upper 5012 Oct 2.13 13.46 14.14 0.39 0.38 0.002673 0.81 2.63 6.71 Upper 5012 Mar 2.97 13.46 14.23 0.46 0.45 0.002673 0.90 3.29 7.09 Upper 4909 Oct 2.13 13.19 13.87 0.40 0.39 0.002573 0.80 2.66 6.73 Upper 4909 Mar 2.97 13.19 13.96 0.46 0.45 0.002678 0.90 3.29 7.09 Upper 4817 Oct 2.13 12.95 13.63 0.39 0.38 0.002619 0.80 2.65 6.72 Upper 4817 Mar 2.97 12.95 13.72 0.46 0.45 0.002697 0.91 3.28 7.09 Upper 4711 Oct 2.13 12.67 13.34 0.39 0.38 0.002745 0.82 2.61 6.70 Upper 4711 Mar 2.97 12.67 13.44 0.46 0.45 0.002736 0.91 3.26 7.08 Upper 4619 Oct 2.13 12.42 13.10 0.39 0.38 0.002627 0.80 2.65 6.72 Upper 4619 Mar 2.97 12.42 13.19 0.46 0.45 0.002717 0.91 3.27 7.08 Upper 4541 Oct 2.13 12.22 12.84 0.35 0.34 0.004138 0.94 2.27 6.50 Upper 4541 Mar 2.97 12.22 12.93 0.42 0.40 0.004144 1.05 2.84 6.83 Upper 3016 Oct 2.13 11.67 12.21 0.29 0.28 0.003257 1.21 1.76 6.14 Upper 3016 Mar 2.97 11.67 12.28 0.34 0.33 0.003301 1.37 2.17 6.36 Upper 3003 Oct 2.13 11.67 12.05 0.19 0.19 0.022297 2.43 0.88 4.59 Upper 3003 Mar 2.97 11.67 12.10 0.22 0.21 0.022534 2.65 1.12 5.18 Upper 2800 Culvert Upper 2650 Oct 2.34 10.69 11.35 0.37 0.36 0.001336 0.92 2.53 6.81 Upper 2650 Mar 3.22 10.69 11.44 0.43 0.42 0.001367 1.03 3.13 7.23 Upper 2203 Oct 2.34 10.01 10.67 0.37 0.36 0.001366 0.93 2.52 6.79 Upper 2203 Mar 3.22 10.01 10.76 0.43 0.42 0.001339 1.02 3.15 7.24 Upper 2030 Oct 2.34 9.70 10.38 0.39 0.38 0.001141 0.88 2.67 6.91 Upper 2030 Mar 3.22 9.70 10.46 0.45 0.43 0.001209 0.99 3.26 7.32 Upper 1497 Oct 2.34 8.99 9.61 0.35 0.34 0.001886 1.05 2.24 6.47 Upper 1497 Mar 3.22 8.99 9.70 0.42 0.41 0.001693 1.12 2.87 6.85 Upper 1001 Oct 2.34 8.41 9.17 0.46 0.44 0.000638 0.73 3.22 7.05 Upper 1001 Mar 3.22 8.41 9.27 0.53 0.51 0.000665 0.82 3.94 7.45 Upper 490 Oct 2.34 7.73 8.12 0.20 0.19 0.022977 2.52 0.93 4.72 Upper 490 Mar 3.22 7.73 8.18 0.22 0.22 0.022454 2.70 1.19 5.35 Upper 427.3552 Oct 2.34 7.50 7.98 0.39 0.39 0.000548 0.62 3.80 9.68 Upper 427.3552 Mar 3.22 7.50 8.07 0.45 0.44 0.000595 0.70 4.60 10.29 Upper 370.2063 Oct 2.34 7.50 7.95 0.37 0.36 0.000724 0.68 3.45 9.41 Upper 370.2063 Mar 3.22 7.50 8.03 0.42 0.41 0.000773 0.77 4.20 10.00 Upper 106.7341 Oct 2.34 7.30 7.62 0.27 0.27 0.002554 1.04 2.24 8.22 Upper 106.7341 Mar 3.22 7.30 7.66 0.31 0.31 0.002949 1.22 2.64 8.55 Upper 86.6344 Oct 2.34 7.30 7.44 0.13 0.13 0.026008 2.04 1.15 8.86 Upper 86.6344 Mar 3.22 7.30 7.47 0.16 0.16 0.024376 2.25 1.43 9.06 Upper 0.0000 Oct 2.34 5.00 7.08 1.49 1.38 0.000003 0.11 20.70 13.90 Upper 0.0000 Mar 3.22 5.00 7.34 1.64 1.52 0.000004 0.13 24.44 14.89 WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘E’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘E’ Streambed Mix Design MODIFIED CRITICAL SHEAR STRESS Project Name: Project No.:221-008-016 Description: Date:5/18/2018 Calc. By:JJT Step 1: Calculate Average Boundary Shear Stress Hydraulic Radius (ft)R 3.14 Energy Slope (ft/ft) S 0.000935 Shear Stress (lb/ft2)τC 0.1832 Step 2: Calculate 50th Percentile Particle Diameter Particle Diameter (in)D50 0.4800 Notes: (1) Equation E.1 of the U.S. Department of Agriculture Forest Service Stream Simulation: An Ecologocial Approach to Providing Passage for Aquatic Organisms at Road-Stream Crossings. (2) Equation E.4 of the U.S. Department of Agriculture Forest Service Stream Simulation: An Ecologocial Approach to Providing Passage for Aquatic Organisms at Road-Stream Crossings , rearranged to solve for diameter, D, in inches. Rolling Hills Creek Crossing King County, WA I-405 / SR 167 DC Streambed Design D50 Energy Grade Line HEC-RAS Future Potential Daylight to Springbrook Hydraulic Radius HEC-RAS Future Potential Daylight to Springbrook τܥ =γܴܵ, where γ=62.4 ௟௕ ௙௧ య (1) ܦ=ଵଶத೎ ଵ଴ଶ.଺த∗ where τ ∗= 0.045 (2) Project Name:I-405/SR 167 Direct ConnectProject No.:221-010-16Description:Rolling Hills Creek CrossingDate:5/17/2018Calc. By:JJTMix Ratios1.5" Washed 1" Screened50% 50%163169Sieve Size(inches)(mm) (in) (ft)% Retained % Passing% Retained% Passing 1.5" Washed 1" Screened1.5" Washed1" ScreenedTotal Weight (lb) % Retained % PassingDiameter (inches)Class Size (D)12 307 12.10 1.008 0% 100% 0% 100% 0 0 0 0 0 0% 100%10 257 10.10 0.842 0% 100% 0% 100% 0 0 0 0 0 0% 100%8 206 8.10 0.675 0% 100% 0% 100% 0 0 0 0 0 0% 100%6 155 6.10 0.508 0% 100% 0% 100% 0 0 0 0 0 0% 100%5 130 5.10 0.425 0% 100% 0% 100% 0 0 0 0 0 0% 100%4 104 4.10 0.342 0% 100% 0% 100% 0 0 0 0 0 0% 100.0%3 79 3.10 0.258 0% 100% 0% 100% 0 0 0 0 0 0% 100.0%2.5 66 2.60 0.217 0% 100% 0% 100% 0 0 0 0 0 0% 100%2 53 2.10 0.175 0% 100% 0% 100% 0 0 0 0 0 0% 100%1.5 41 1.60 0.133 0% 100% 0% 100% 0 0 0 0 0 0% 100% 1.60 100%1.25 34 1.35 0.113 23% 77% 0% 100% 115 0 506115 0 506115 11% 89% 1.25 84%1 28 1.10 0.092 24% 53% 0% 100% 120 0 528120 0 528120 12% 77%0.75 20 0.80 0.067 40% 13% 0% 100% 198 0 871398 0 871398 19% 57% 0.62 50%No. 4 (4.75 mm) 4.80 0.20 0.017 13% 0% 35% 65% 67 175 294867 798525 1093392 24% 33% 0.08 16%No. 40 (0.425 mm)0.450.020.0010%0%49%16%024501117935111793525%8%No. 200 (0.075 mm) 0.080 0.003 0.000 0% 0% 7% 9% 0 36 0 164268 164268 4% 4%Pan0.0500.0020.0000%0%9%0%04402007722007724%0%100%100%500500220050022815004482000100%Notes:Design Combined1. Modified Streambed Sediment Gradation based on submittal gradation.Weight (lb)5001.5" Washed 1" ScreenedAverage Diameter RetainedVolume (CY)Design Class Size (interpolated)Per 1000 ft^3 volumeUnit Weights (lb/cf)500Modified Streambed SedimentGradation Project Name:I-405/SR 167 Direct ConnectProject No.:221-010-16Description:Rolling Hills Creek CrossingDate:5/18/2018Calc. By:JJTMix RatiosModified Streambed Sediment4" Streambed Cobbles80% 20%WSDOT Streambed Aggregates Standard Specification 9-03.11166 145Sieve Size(inches)(mm) (in) (ft)% Retained % Passing% Retained% PassingModified Streambed SedimentWSDOT 4" CobblesModified Streambed SedimentWSDOT 4" CobblesTotal Weight (lb) % Retained % PassingDiameter (inches)Class Size (D)Diameter (inches)Class Size (D)12 307 12.10 1.008 0% 100% 0% 100% 0 0 0 0 0 0% 100%10 257 10.10 0.842 0% 100% 0% 100% 0 0 0 0 0 0% 100%8 206 8.10 0.675 0% 100% 0% 100% 0 0 0 0 0 0% 100%6 155 6.10 0.508 0% 100% 0% 100% 0 0 0 0 0 0% 100%5 130 5.10 0.425 0% 100% 0% 100% 0 0 0 0 0 0% 100%4 104 4.10 0.342 0% 100% 0% 100% 0 0 0 0 0 0% 100.0% 4.10 100% 3.00 100%3 79 3.10 0.258 0% 100% 10% 90% 0 20 0 78300 78300 2% 98.2%2.5 66 2.60 0.217 0% 100% 10% 80% 0 20 0 78300 78300 2% 96%2 53 2.10 0.175 0% 100% 10% 70% 0 20 0 78300 78300 2% 95%1.5 41 1.60 0.133 0% 100% 30% 40% 0 60 0 234900 234900 5% 89% 1.48 84% 1.20 84%1.25 34 1.35 0.113 11% 89% 10% 30% 88 20 394416 78300 472716 11% 78%1 28 1.10 0.092 12% 77% 15% 15% 96 30 430272 117450 547722 13% 66%0.75 20 0.80 0.067 20% 57% 15% 0% 160 30 717120 117450 834570 19% 47% 0.85 50% 0.48 50%No. 4 (4.75 mm) 4.80 0.20 0.017 24% 33% 0% 0% 192 0 860544 0 860544 20% 27% 0.10 16% 0.15 16%No. 40 (0.425 mm) 0.45 0.02 0.001 25% 8% 0% 0% 200 0 896400 0 896400 21% 7%No. 200 (0.075 mm) 0.080 0.003 0.000 4% 4% 0% 0% 29 0 129082 0 129082 3% 4%Pan 0.050 0.002 0.000 4% 0% 0% 0% 35 0 157766 0 157766 4% 0%100% 100% 800 200 3585600 783000 4368600 100%Notes:ft inD1000.25 3.00Equation 3.6: D84 / D100 =0.4D840.10 1.20Equation 3.7: D84 / D50 = 2.5D500.040 0.48D160.01 0.15Equation 3.8: D84/ D16=8.0Streambed MixDesignPer 1000 ft^3 volume Unit Weights (lb/cf)800 200Modified Streambed SedimentWSDOT 4" CobblesAverage Diameter Retained Volume (CY) Weight (lb) Design CombinedDesign Class Size (interpolated)Critical Shear Stress AnalysisDistribution per Equations 3.6-3.8 2013WDFW Water Crossing Guidelines1. Modified Streambed Sediment Gradation based on submittal gradation.2. 4" Cobbles estimated based on Standard Specification percent passing 0%10%20%30%40%50%60%70%80%90%100%0.1 1 10Percent FinerParticle size, inchesCritical ShearAnalysisDesign WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘F’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘F’ Scour Calculations Project Name:I-405/SR 167 Direct Connect Project No.:221-008-16 Description: Date:5/18/2018 Calc. By:JJT The following calculations are made using Laursen's Equation (HEC-18, 5th edition (equation 6.1, page 6.2)): Legend "inputs" "coefficients or constants" "calculated values" = 50.50 = 26.26 = 1.92 = 0.0708 See note 1 = 11.17 = 5.15 = 143.00 = 2.83 = CLEAR-WATER INCIPIENT DISCHARGE MAIN CHANNEL SCOUR MODE Rolling Hills Creek 1 - D 50 is taken from design streambed mix. Ku: (unit correction coefficient) Q1: DISCHARGE IN APPROACH CHANNEL (cfs) Vm: MEAN VELOCITY IN APPROACH CHANNEL (fps) MAIN CHANNEL SCOUR MODE Vc: BED TRANSPORT CRITICAL VELOCITY (fps) D50: MEDIAN GRAIN SIZE (ft) A1: APPROACH SECTION MAIN CHANNEL AREA (ft2) W1: APPROACH SECTION MAIN CHANNEL WIDTH (ft) Y1: APPROACH SECTION AVERAGE CHANNEL DEPTH (ft) Rolling Hills Creek Crossing ܸ௖ =ܭݑ ∗ܻଵଵ/଺ ∗ ܦହ଴ଵ/ଷ ܻଵ = ஺భ ௐభൗ Project Name:I-405/SR 167 Direct Connect Project No.:221-008-16 Description: Date:5/18/2018 Calc. By:JJT Legend "inputs" "coefficients or constants" "calculated values" = 143.00 = 6.00 1 = 0.0885 2 = 0.0077 = 3.76 Y0: AVERAGE EXISTING DEPTH IN THE CONTRACTED SECTION (ft)= 3.35 3 YS: AVERAGE CONTRACTION SCOUR DEPTH (ft)= 0.41 Notes: 3 - Depth is depth upstream from HEC-RAS. 100-YR CLEAR-WATER CONTRACTION SCOUR Rolling Hills Creek The following calculations are made using the Clear-Water Contraction Scour Equation (HEC-18, 5th edition (equation 6.4 & 6.5, page 6.12)): Rolling Hills Creek 2 - Because D50 is not the largest particle in the bed material, the scoured section can be slightly armored. Therefore, the Dm is assumed to be 1.25xD50. 1 - Width is bottom width of main channel Q: DISCHARGE IN CONTRACTED SECTION (cfs) W: WIDTH OF CONTRACTED SECTION (ft) Dm: DIA OF SMALLEST NONTRANSPORTABLE PARTICLE IN BED (ft) Y2: CALCULATED WATER DEPTH OF CONTRACTED SECTION (ft) Ku: CLEAR-WATER CONTRACTION SCOUR COEFFICIENT ܻ௦ = ܻଶ − ܻ଴ ܻଶ =[ܭ௨ ܳଶ ܦ௠ ଶ ଷൗܹ ଶ]ଷ ଻ൗ Project Name: Project No.:221-008-16 Description: Date:5/22/2018 Calc. By:JJT The following calculations follow Design Guideline 14 HEC-23, 3rd edition Legend "inputs" "coefficients or constants" "calculated values" = 3.35 = 32.2 Ss: Specific Gravity of Rock = 2.65 = 0.89 Spill-through = 3.25 =0.18D50: MEDIAN GRAIN SIZE (ft) K: Coeffecient for Abutment Type V: Velocity in Contracted Section RIP-RAP SIZING FOR ABUTMENTS y: Depth (ft) G: gravitational acceleration (fps) ROCK FOR CULVERT END I-405/SR 167 Direct Connect Rolling Hills Creek D50/y = (K/(Ss-1)[V2/gy] Project Name:I-405/SR 167 Direct Connect Project No.:221-008-16 Description: Date:5/18/2018 Calc. By:JJT The following calculations are made using Laursen's Equation (HEC-18, 5th edition (equation 6.1, page 6.2)): Legend "inputs" "coefficients or constants" "calculated values" = 50.50 = 26.26 = 1.92 = 0.0708 See note 1 = 11.17 = 5.15 = 143.00 = 2.83 = CLEAR-WATER INCIPIENT DISCHARGE MAIN CHANNEL SCOUR MODE Rolling Hills Creek 1 - D 50 is taken from design streambed mix. Ku: (unit correction coefficient) Q1: DISCHARGE IN APPROACH CHANNEL (cfs) Vm: MEAN VELOCITY IN APPROACH CHANNEL (fps) MAIN CHANNEL SCOUR MODE Vc: BED TRANSPORT CRITICAL VELOCITY (fps) D50: MEDIAN GRAIN SIZE (ft) A1: APPROACH SECTION MAIN CHANNEL AREA (ft2) W1: APPROACH SECTION MAIN CHANNEL WIDTH (ft) Y1: APPROACH SECTION AVERAGE CHANNEL DEPTH (ft) Rolling Hills Creek Crossing ܸ௖ =ܭݑ ∗ܻଵଵ/଺ ∗ ܦହ଴ଵ/ଷ ܻଵ = ஺భ ௐభൗ WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘G’ LWD Anchoring WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 LWD Brush Pile Buoyancy Calculations Volume of 18-inch diameter by 20-feet long log, ܮ݋݃ଵ = ሺଵ.ହ௙௧ሻమ ସ ߨ ݔ 20݂ݐ = 35.34 ݂ݐ ଷ Volume of 12-inch diameter by 20-feet long log, ܮ݋݃ଶ = ሺଵ௙௧ሻమ ସ ߨ ݔ 20݂ݐ = 15.71 ݂ݐ ଷ Volume of 12-inch diameter by 16-feet long log, ܮ݋݃ଷ = ሺଵ௙௧ሻమ ସ ߨ ݔ 16݂ݐ = 12.57 ݂ݐ ଷ Volume of 6-inch diameter by 16-feet long log, ܮ݋݃ସ = ሺ଴.ହ௙௧ሻమ ସ ߨ ݔ 16݂ݐ = 3.14 ݂ݐ ଷ Volume of rootwad, ܴ݋݋ݐ = 0.6 ݔ ሺଷ௙௧ሻమ ସ ߨ ݔ 2 ݂ݐ = 8.48 ݂ݐ ଷ Volume of brush pile, ܤݎݑݏℎ = 0.6 ݔ 91 ݏ݂ ݔ 2.7 ݂ݐ = 147.42 ݂ݐ ଷ Total Volume of LWD, ܸ݋݈ = ܮ݋݃ଵ +ܮ݋݃ଶ +ܮ݋݃ଷ +4ݔܮ݋݃ସ + ܴ݋݋ݐ ܸ݋݈ = 35.34݂ݐ ଷ + 15.71݂ݐ ଷ + 12.57݂ݐ ଷ +4ݔሺ3.14݂ݐ ଷ ሻ +8.48݂ݐଷ + 147.42݂ݐ ଷ = 232.08 ݂ݐ ଷ The buoyant force on the structure is equal to the weight of the water displaced by the structure, less the weight of the structure. ܨ஻௨௢௬௔௡௧ = 232.08݂ݐ ଷ ݔ ൬62.4 ݈ܾ ݂ݐ ଷ −22 ݈ܾ ݂ݐ ଷ ൰ = 9,376 ݈ܾ ≈ 9.4 ݇݅݌ݏ The anchoring force required to resist buoyancy with a safety factor of 2.0 is calculated as: ܨ௔ =2.0 ݔ ܨ஻ =18.8 ݇݅݌ݏ The anchoring force will be provided by 3 MR-1 anchors per brush pile. Per the Drainage Geotechnical Design Memorandum each MR-1 anchor will provide 8 kips of resistance for a total of 24 kips of resistance. This provides a factor of safety of 2.55. WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ 34 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Bioengineered Bank Protection Buoyancy Calculations Buoyancy resistance was calculated at the location of each buried trunk along the stream channel as shown on the Plans. Volume of 18-inch diameter by 20-feet long log, ܮ݋݃ଵ = ሺଵ.ହ௙௧ሻమ ସ ߨ ݔ 20݂ݐ = 35.34 ݂ݐ ଷ Volume of 8-inch diameter by 20-feet long log, ܮ݋݃ଶ = ሺ଴.଺଻௙௧ሻమ ସ ߨ ݔ 20݂ݐ = 6.98 ݂ݐ ଷ Volume of rootwad, ܴ݋݋ݐ = 0.6 ݔ ሺଷ௙௧ሻమ ସ ߨ ݔ 2݂ݐ = 8.48 ݂ݐ ଷ See the attached LWD Anchoring Free Body Diagrams (1-4) for calculation graphical inputs. The buoyant force on the structure is equal to the weight of the water displaced by the water, less the weight of the structure. ܨ஻ଵ =35.34 ݂ݐଷ ݔ ൬62.4 ݈ܾ ݂ݐ ଷ −22 ݈ܾ ݂ݐ ଷ ൰ = 1,428 ݈ܾ ܨ஻ଶ =6.98 ݂ݐଷ ݔ ൬62.4 ݈ܾ ݂ݐ ଷ −22 ݈ܾ ݂ݐ ଷ ൰ = 282 ݈ܾ ܨ஻ଷ =8.48 ݔ ൬62.4 ݈ܾ ݂ݐ ଷ −22 ݈ܾ ݂ݐ ଷ ൰ = 343݈ܾ The total buoyant force acting on the structure is: ܨ஻ =ܨ஻ଵ +ܨ஻ଶ +ܨ஻ଷ = 2,053 ݈ܾ The buoyant force is resisted by the buoyant weight of the soil above the log. The soil is assumed to be Common Borrow (ESU-1B). Per the Drainage Geotechnical Design Memorandum Common Borrow is assumed to have a unit saturated weight of 120 lb/ft3 and a soil friction angle of 32⁰. The amount of soil above the log was calculated by multiplying the cross-sectional area above the log by the log diameter. The buoyant unit weight of the soil is calculated as the saturated unit weight, less the unit weight of water. ߛ஻௨௢௬௔௡௧ = 120 ݈ܾ ݂ݐ ଷ −62.4 ݈ܾ ݂ݐ ଷ = 57.6 ݈ܾ ݂ݐ ଷ The total weight of soil above the log is calculated as: ܹௌଵ =1.5 ݂ݐ ݔ 2.5 ݂ݐ 2 ݔ 12.7 ݂ݐ ݔ 57.6 ݈ܾ ݂ݐ ଷ = 1,372 ݈ܾ ܹௌଶ = 1.5 ݂ݐ ݔ 2.0 ݂ݐ ݔ 12.7 ݂ݐ ݔ 57.6 ݈ܾ ݂ݐ ଷ = 2,195 ݈ܾ ܹௌଷ =1.5 ݂ݐ ݔ 2.0 ݂ݐ 2 ݔ 3.0 ݂ݐ ݔ 57.6 ݈ܾ ݂ݐ ଷ = 259 ݈ܾ ܹௌ =ܹௌଵ +ܹௌଶ +ܹௌଷ = 3,826 ݈ܾ WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ 35 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 The anchoring force required to resist buoyancy with a safety factor of 2.0 is calculated as: ܨ௔ =2.0 ݔ ܨ஻ − ܹௌ = 280 ݈ܾ The anchoring force will be provided by 1 MR-1 anchor per 18” diameter log which will provide 8 kips of resistance. This is a factor of safety of 28.6. Bioengineered Bank Protection Moment Calculations Due to the unbalance locations of the forces activing on the log the anchoring force must also resist moment. Moment is calculated about a Point O, shown on Free Body Diagram 4, with a safety factor of 2.0, to be: ܯை = −4.3 ݂ݐ ݔ ܹௌଵ − 6.4 ݂ݐ ݔ ܹௌଶ +10.0 ݂ݐ ݔ ܨ஻ଵ −13.7 ݂ݐ ݔ ܹௌଷ +18.4 ݂ݐ ݔ ܨ஻ଶ −18.4 ݂ݐ ݔ ܨ௔ 2+20.8 ݂ݐ ݔ ܨ஻ଷ =0 ݈ܾ݂ݐ ܯை = −4.3 ݂ݐ ݔ 1,372 ݈ܾ − 6.4 ݂ݐ ݔ 2,195 ݈ܾ + 10.0 ݂ݐ ݔ 1,428 ݈ܾ − 13.7 ݂ݐ ݔ 259 ݈ܾ + 15.7 ݂ݐ ݔ 282 ݈ܾ −18.4 ݂ݐ ݔ ܨ௔ 2 + 20.8 ݂ݐ ݔ 343 ݈ܾ = 0 ݈ܾ݂ݐ ܯை = −5,900 ݈ܾ݂ݐ − 14,048 ݈ܾ݂ݐ + 14,280 ݈ܾ݂ݐ − 3,548 ݈ܾ݂ݐ + 4,427 ݈ܾ݂ݐ − 18.4 ݂ݐ ݔ ܨ௔ 2 + 7,134 ݈ܾ݂ݐ =0 ݈ܾ݂ݐ 18.4 ݂ݐ ݔ ܨ௔ 2 = 2,345 ݈ܾ݂ݐ ܨ௔ = 255 ݈ܾ The anchoring force will be provided by 1 MR-1 anchor per 18” diameter log which will provide 8 kips of resistance. Bioengineered Bank Protection Slippage Calculations The lateral force inducing slipping is calculated as: ܨௌ௟௜௣ = ܨ஻ ݔ ݏ݅݊൫ݐܽ݊ିଵ ሺܵሻ൯ = 2,053 ݈ܾ ݔ ݏ݅݊൭ݐܽ݊ ିଵ ൬ 2.5 ݂ݐ 12.7 ݂ݐ ൰൱ = 397 ݈ܾ Where S is the slope of the log. The normal force acting on the trunk is calculated as: ܨே௢௥௠௔௟ = ሺܨ஻ +ܹௌ ሻ ݔ ܿ݋ݏ൫ݐܽ݊ିଵ ሺܵሻ൯=ሺ2053 ݈ܾ + 3,826 ݈ܾ ሻ ݔ ܿ݋ݏ൭ݐܽ݊ିଵ ൬ 2.5 ݂ݐ 12.7 ݂ݐ൰൱ = 5,768 ݈ܾ WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ 36 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 The maximum friction force resisting slipping is calculated as: ܨி௥௜௖௧௜௢௡ = ܨே௢௥௠௔௟ ݔ ݐܽ݊ሺߠሻ = 5,768 ݔ ݐܽ݊ ሺ32°ሻ = 3,604 ݈ܾ Where ߠ is the soil friction angle. The Safety Factor for slipping is calculated as: ܨܵ = ܨி௥௜௖௧௜௢௡ ܨௌ௟௜௣ = 3,604 ݈ܾ 397 ݈ܾ =9.08 Cable Tension Calculation The anchors will be secured to the logs using 0.25” diameter stainless steel EIPS cable. The breaking strength per cable is 5.8 kips. The cables will be looped through the anchors, providing a total tensile strength of 11.6 kips per anchor, which greater than the loading capacity of the anchor. WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘G’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533F: 425.486.6593 MANTA RAY® Manufacturers Loading Specifications Soil Description Blow Count (N) MR-68Ultimate:5 kips MR-88 Ultimate:10 kips MR-4 Ultimate:16 kips MR-3 Ultimate:20 kips MR-2 Ultimate:40 kips MR-1 Ultimate:40 kips MR-SR Ultimate: 40 kips Very dense/cemented sands Coarse gravel and cobbles 60-100+ 5 (1,3) 10 (1,3) 16 (1,3) 20 (1,3) 28-40 (1,3,4) 40 (1,3) 40 (1,3,5) Dense fine compacted sands very hard silts or clays 45-60 3-4 (2,3,4) 6-10 (2,3,4) 9-16 (2,3,4)17-20 (2,3,4) 21-28 (2,4)36-40 (1,3,4) 40 (1,3) Dense clays, sands and gravels hard silts and clays 35-50 2.2-3 (4) 4-6 (4) 6-9 (4) 12-18 (2,4) 15-22 (2,4) 24-36 (2,4)32-40 (2,3,4) Medium dense sandy gravel stiff to hard silts and clays 24-40 1.5-2 (4) 3-4 (4) 4.5-5.5 (4) 9-14 (4) 12-18 (4) 18-20 (2,4) 24-34 (2,4) Medium dense coarse sand and sandy gravel stiff to very stiff silts and clays 14-25 1.1-1.5 (4) 2-3 (4) 3.5-4.5 (4) 7-9 (4) 9-12 (4) 15-20 (4) 18-24 (4) Loose to medium dense fine to coarse sandfirm to stiff clays and silts 7-14 0.9-1.2 (4) 1.5-2.5 (4) 2.5-4 (4) 5-8 (4) 7-10 (4) 10-15 (4) 14-18 (4) Loose find sand, alluvium, soft clays fine saturated silty sand 4-8 0.6-1.0 (4)0.9-1.5 (4,6) 1.5-2.5 (4) 3-5 (4,6) 5-8 (4,6) 8-12 (4,6) 9-14 (4,6) Peat, organic silts; Inundates silts fly ash 0-5 -5 0.2-0.9 (4,6) 0.3-1.5 (4,6) 0.8-3 (4,6) 2-5 (4,6) 3-8 (4,6) 4-12 (4,6) The design proposes to use MR-1 anchors for all applications. WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘H’ SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 ATTACHMENT ‘H’ Floodplain Storage Floodplain Storage Impact Analysis The project proposes widening along northbound SR 167 that will impact the City of Renton Flood Storage in the Rolling Hills Creek and Panther Creek wetland complex. A floodplain storage impact analysis was performed to assure that the impacts will not reduce the volume of storage within the wetland from elevation ranges of 5’ to 14’, 14’ to 15’, 15’ to 16’, and 16’ to 19.58’. The existing wetland has deadpool storage with a static water surface elevation of 17’. The proposed stream realignment and restoration of Rolling Hills Creek will drain this deadpool storage, increasing the overall floodplain storage in the wetland. For each range, the floodplain storage impact analysis consisted of two main steps: calculating cut and fill quantities and calculating the removal of deadpool storage. Step 1 Cut and fill quantities for each range were calculated using the Average End Error method. Cross- sections were analyzed along the NB167 alignment at 50 ft. increments. The cross-sectional area of cuts and fills were measured within each elevation range. The average of each measurement between consecutive cross-sections was multiplied by the distance between cross-sections to calculate an average volume. Step 2 Deadpool storage removal was calculated measuring the area of existing contours at the limits of each elevation range. The average of each measurement between consecutive contours were multiplied by the depth of the elevation range to calculate an average volume. Deadpool storage removal was not calculated for the range between 5’ and 14’ because it is below the proposed stream channel and therefore will not be drained. WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘H’ 39 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘H’ 40 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 WSDOT Northwest Region Hydraulic Review Team May 2018 I-405/SR 167 Direct Connector Rolling Hills Creek Technical Memorandum Attachment ‘H’ 41 SDA 1724 W. Marine View Drive, Suite 140 Everett, WA 98201 P: 425.486.6533 F: 425.486.6593 Results The results of the analysis are summarized in the table below. FLOODPLAIN STORAGE IMPACT VOLUMES (CUBIC YARDS) Total (Elevation 19.58* to 5) Elevation 19.58* to 16 Elevation 16 to 15 Elevation 15 to 14 Elevation 14 to 5 Area Volume Material added to Flood Plain Volume Material taken out of Flood Plain Volume Materia l added to Flood Plain Volume Materia l taken out of Flood Plain Volume Materia l added to Flood Plain Volume Materia l taken out of Flood Plain Volume Materia l added to Flood Plain Volume Materia l taken out of Flood Plain Volume Materia l added to Flood Plain Volume Materia l taken out of Flood Plain SR 167- Areas Southbound/ West Side of Road 57 74 57 74 - - - - - - Northbound/East Side (North of 19th Street Utility Berm) 1,857 2,624 1,745 1,294 100 672 11 433 0 225 East Side (South of 19th Street Utility Berm) 1,607 42 1,505 42 98 - 4 - - - Wetland pool (dead storage removed by new Rolling Hills Creek and Fish Passage) - 107,984 - 56,090 - 38,211 - 13,682 Subtotal – Direct Connect Project 3,521 110,724 3,307 57,501 199 38,883 15 14,115 0 225 Net Floodplain Volume Created 107,203 54,194 38,685 14,099 225