Alternatives for Willow Creek Flood Mitigation Study

Transcription

1 Alternatives for Willow Creek Flood Mitigation Study Presented by: Anil Tangirala, PE, CFM, ENV SP ms consultants, inc. June 22, 2016

2 Presentation Overview Introduction Project Background Willow Creek Existing Flooding Project Goals Hydrologic and Hydraulic Analysis Alternatives for Flood Mitigation Modeling LID tools in HEC-RAS Summary and Conclusions

3 Flood Mitigation What is Flood Mitigation? Sustained action to reduce or eliminate long term risk to people and property from flood hazards Structural Flood Mitigation Alternatives include: Upsizing culverts Acquisition/demolition of repetitively flooded structures Flood storage detention Structural elevation

4 Where is the project?

5 What are the goals of this project? Reduce Congestions/Improve Safety Roadway Widening and Intersection Improvements Mitigate Flooding

6 What are the goals of this project? Reduce Congestions/Improve Safety Roadway Widening and Intersection Improvements Mitigate Flooding

7 What is the scope of the project? Phase I Alternatives Evaluation Conduct existing System Hydrologic and Hydraulic Analysis Identify Hydraulic Bottlenecks/Pinch Points in the Existing System Develop Flood Mitigation Alternatives Develop Planning level Cost Estimates Phase II Detailed Design Project funded through federal earmark for transportation and flooding.

8 Project Background

9 Project Background

10 Willow Creek Just DS of Sheetz Gas Station

11 Willow Creek At Shepherd of the Valley Assisted Living Entrance Drive

12 Willow Creek at Sharrott Road

13 Willow Creek at Western Reserve Road

14 Willow Creek at Private Drive of Apartment Complex

15 Willow Creek at Private Drive for Daycare Center

16 Willow Creek at Hitchcock Road

17 Existing Flooding

18 Western Reserve Road near Sharrott Road June 26, 2015 Flooding

19 Flooding on Western Reserve Road June 23 rd, 2015 Flooding

20 June 23 rd, 2015 Flooding Flooding Near Metro Park

21 PRECIPITATION (INCHES) June 2015 Rainfall in Youngstown, Ohio 2 June 2015 Rainfall Data For Youngstown, Ohio yr - 10yr Storm Event 1yr - 5yr Storm Event Jun 4-Jun 7-Jun 10-Jun 13-Jun 16-Jun 19-Jun 22-Jun 25-Jun 28-Jun Historical Average Rainfall (inches) Total Recorded Rainfall (inches)

22 Flooding near Market Street

23 ODOT SR-7 Hydraulic Study Flooding also occurs north of CR 32 along the west side of the SR-7 roadway and within the Antone s Banquet Centre parking area during moderate to heavy storms. Several culvert improvements proposed as part of this study conducted by ODOT.

24 ODOT SR-7 Hydraulic Study

25 ODOT SR-7 Hydraulic Study

26 Existing Conditions Hydrologic Analysis Hydrologic Analysis using USACE HEC-HMS Sub-basins delineations Time of concentrations and curve numbers Reach Routing Muskingum Cunge Boundary Conditions ODOT SR-7 Study

27 Drainage Basins

28 RECURRENCE Existing Hydrologic Analysis Results Flow Change Location Peak Discharge (cfs) Sheetz CMP Shepherd of the Valley Assisted Living Entrance Sharrott Road Western Reserve Road Private Drive (Apartment Complex) Private Drive (Daycare Center) Hitchcock Road 2-YEAR YEAR YEAR YEAR YEAR YEAR

29 Existing Conditions Hydraulic Analysis Hydraulic Analysis using USACE HEC-RAS Cross-section and Channel Geometry Roughness- Channel and Overbank Manning s Peak Discharges Boundary Conditions- Downstream

30 Willow Creek Hydraulics

31 Existing Conditions Flood Profiles

32 Existing Conditions Level of Service Culvert Location Culvert Size and Type Approx. Culvert Opening Area (Sq. Ft.) Existing Level of Service Shepherd of the Valley Driveway Sharrott Road Western Reserve Road/CR-32 Private Drive Bridge Private Daycare Bridge 3 x 6 x4.5 Elliptical CMP Culverts 2 x 48 Circular CMP Culverts 1 x 12 x 5 Stone Abutment Structure Wooden planks on Steel I-beam Bridge 2 x 5.5 x4 Elliptical CMP Culverts sq. ft. 2-year Storm Event sq. ft. <2-year Storm Event sq. ft. 2-year storm event sq. ft. <5-year Storm Event sq. ft. 2-year Storm Event Hitchcock Road 14 Span Slab Bridge sq. ft. 100-Year Storm Event

33 Proposed Condition Level of Service Goals All water crossings to be mitigated to atleast meet LOS requirements based on Mahoning County Regulation. One driveway is a an entrance to a Old Age Home and classifies as a Critical Facility Higher level of protection planned for the Critical Facility Under Executive Order 11988, Floodplain Management, Federal agencies funding and/or permitting critical facilities are required to avoid the 0.2% (500-year) floodplain or protect the facilities to the 0.2% chance flood level.

34 Flood Mitigation Alternatives Several Alternatives developed and evaluated Alternative 1a Culvert Upgrades Alternative 1b Culvert Upgrades and new Driveway Alternative 2 Diversion Alternative 3 - Detention

35 Alternative 1a Culvert Upgrades

36 Alternative 1a Culvert Upgrades Culvert Location Shepherd of the Valley Driveway Sharrott Road Western Reserve Road/CR-32 Private Drive Bridge Private Daycare Bridge Existing Culvert Size and Type 3 x 6 x4.5 Elliptical CMP Culverts 2 x 48 Circular CMP Culverts 1 x 12 x 5 Stone Abutment Structure Wooden planks on Steel I-beam Bridge 2 x 5.5 x4 Elliptical CMP Culverts Proposed Culvert Size and Type 22 x4 Box Culvert 13 x4 Box Culvert 13 x4 Box Culvert Remove Bridge and Extend 13 x4 Box Culvert from Western Reserve Road/CR x5 Box Culvert

37 Alternative 1b Culvert Upgrades & New Driveway

38 Alternative 1b Culvert Upgrades Culvert Location Shepherd of the Valley Driveway Sharrott Road Western Reserve Road/CR-32 Private Drive Bridge Private Daycare Bridge Existing Culvert Size and Type 3 x 6 x4.5 Elliptical CMP Culverts 2 x 48 Circular CMP Culverts 1 x 12 x 5 Stone Abutment Structure Wooden planks on Steel I-beam Bridge 2 x 5.5 x4 Elliptical CMP Culverts Proposed Culvert Size and Type 22 x4 Box Culvert 13 x4 Box Culvert 13 x4 Box Culvert Remove Bridge 12 x5 Box Culvert

39 Alternative 2 Diversion

40 Modeling LIDs in HEC-RAS Pressurized Pipe Flow can be modeled in HEC-RAS Steady and Un-Steady Flow Diversion pipe can be modeled by using cross-sections to model the bottom and LID to model top of the pipe Steady Flow uses standard energy equation and Un-Steady uses Priessman Slot Theory and Water Hammer Equations.

41 Modeling LID in HEC-RAS

42 Calculation of Transition Losses

43 Applications for modeling LIDs in HEC- RAS Long Culverts Tunnels Diversion Pipes/Conduits Culverts with bends-ability to include minor losses.

44 Alternative 2 - Diversion Culvert Location Shepherd of the Valley Driveway Sharrott Road Western Reserve Road/CR-32 Existing Culvert Size and Type 3 x 6 x4.5 Elliptical CMP Culverts 2 x 48 Circular CMP Culverts 1 x 12 x 5 Stone Abutment Structure Proposed Culvert Size and Type 22 x4 Box Culvert 11 x4 Box Culvert 11 x4 Box Culvert

45 Alternative 3 Detention

46 Alternatives Pros & Cons Alternative Description Advantages Disadvantages Hydraulic Alternative 1A Replacement of undersized culverts and extension of Western Reserve Road Culvert Mitigates Flooding No major diversion or detention Will require the extension of the Western Reserve Culvert and earthwork to cover the new structure Hydraulic Alternative 1B Replacement of undersized culverts and removal of the Private Drive downstream of Western Reserve Road Mitigates Flooding Provides property owner access from Western Reserve Road Prevents frequent overtopping of private bridge Restricts access between property owners.

47 Alternatives Pros & Cons Alternative Description Advantages Disadvantages Hydraulic Alternative 2B Replacement of undersized culverts and diversion from Sharott Road to the east side of Hitchcock Road Only requires upsizing of two culverts Does not solve the flooding at the Private Drive culvert Will require the installation of the new 48 diversion storm sewer Hydraulic Alternative 3 Replacement of undersized culverts and construction of a detention basin upstream of the Shepherd of the Valley culvert Reduces peak discharges downstream of the basin Not enough detention, still requires upgrades Significant Environmental Permitting

48 Floodplain Permitting

49 Alternatives Opinion of Probable Costs Alternative Preliminary Costs Alternative 1A $1,242,600 Alternative 1B $1,118,800 Alternative 2A $1,657,800 Alternative 2B $1,771,500 Alternative 3 $1,526,300

50 Conclusions Existing System evaluation helps us understand pinch points in the system H&H useful in analyzing alternatives. Useful tools available within HEC-RAS to model alternatives Coordination with other projects essential Environmental Permitting Requirements

51 Questions Anil Tangirala, PE, CFM, ENV SP ms Consultants Inc