A Study to Estimate Current and Future CSOs to Bubbly Creek and Identify Impacts on the Chicago Area Waterways (CAWS)

Transcription

1 A Study to Estimate Current and Future CSOs to Bubbly Creek and Identify Impacts on the Chicago Area Waterways (CAWS) IWEA WATERCON 2012 Springfield, Illinois March 19, 2012 presented by David Kiel, USACE Paul Shadrake, AECOM US Army Corps of Engineers

2 Presentation Overview Overall Project This Project Where Do We Go Next?

3 Bubbly Creek Project Location Chicago

4 History of Bubbly Creek (South Fork of the South Branch Chicago River)

5 Bubbly Creek Today Length 6,600 feet >30 sq. mi. drainage area Metropolitan Chicago 100,000 within 1-mile 1.4 M within 5-miles 9 gravity CSOs 6,000 cfs CSO pumping capacity at RAPS

6 Racine Avenue Pump Station (RAPS)

7 Bubbly Creek Issues Alterations created urban waterway Stagnant flow conditions Combined sewer overflows Sediment and water quality Habitat/biological integrity Recreation

8 Overall Project - Goals Improve normal flow conditions Reduce impacts of CSOs Reduce impacts from bottom sediments Improve water quality Provide diverse aquatic and related habitats Improve river corridor aesthetics Provide recreational opportunities

9 Overall Project Description 3 year Feasibility Study Project Stakeholders USACE City of Chicago, Department of Environment (Local Sponsor) MWRDGC Others Understand what goes in to Bubbly Creek Evaluate restoration measures to improve what stays in and what goes out of Bubbly Creek Flow Augmentation Selective Dredging Sediment Capping Dissipating Racine Ave. Pump Station (RAPS) Flow Bypassing RAPS Flow Streambank Restoration Wetland Restoration

10 This Project What Goes In! Establish basis for improvement alternative evaluations Develop SWMM model to simulate CSO quantity and quality entering Bubbly Creek Achieve more detailed simulation of CSOs from RAPS and other CSOs along Bubbly Creek Utilize existing USACE calibrated models to the maximum extent practicable

11 Project Approach Utilize existing calibrated USACE model for hydrology (HSPF) New hydraulic model to better simulate pipe network and RAPS operations (SWMM) Simulate water quality in HSPF and SWMM Improve USACE tunnel model to account for TARP utilization (TNET) Develop approach for all model interactions

12 Project Approach Calibrate SWMM Model for period Run 57-Year Period of Record ( ) Model DO, T, BOD, TSS initially Evaluate Existing and Future Conditions: Existing (No McCook TARP Reservoir) Future (With McCook TARP Reservoir) Both Open and Closed Dropshaft Scenarios

13 Hydrology - HSPF Use Calibrated model provided by USACE Subdivide into smaller catchments for input to SWMM Ratio HSPF SCAs by SWMM/HSPF Drainage Area Ratio Check calibration

14 Existing HSPF Sub-Catchments

15 Revised HSPF Sub-Catchments

16 Hydraulics - SWMM City of Chicago InfoWorks Pipe Network Generally 5 Feet or Larger in Diameter Represent RAPS/TARP Operations

17 InfoWorks Pipe Network

18 SWMM Pipe Network

19 Racine Avenue Pump Station (RAPS)

20 Water Quality HSPF and SWMM Parameters: Temperature, DO, BOD, and TSS Utilize HSPF water quality concentrations as inputs in SWMM to model water quality Represents surface and subsurface runoff Water quality constituents combined with watershed loading and transported through sewer network

21 TARP - TNET Improve TARP Mainstream system model TNET tunnel stage output utilized as SWMM input Solves the linearized form of the Saint-Venant equations using a weighted, four-point, implicit solution technique Ability to simulate dendritic tunnel networks from partially full to pressurized conditions Capability to model tunnels, dropshafts, gates, reservoirs, pumping at WWTPs, and surge attenuation

22 TARP - TNET

23 HSPF model complete Project Status SWMM model complete Pipe Network RAPS Operating Procedures SWMM and TNET models calibrated and verified for 5 year data period Models (Hydraulic and Water Quality) run(s!) completed for Existing Conditions over period of record (1949 to 2007)

24 Where Do We Go Next? Evaluate Future Conditions: Future with McCook Reservoir Two drop shaft conditions: fully open and partially closed Results used as input to evaluate alternatives for ecosystem restoration of Bubbly Creek Consider other water quality parameters

25 Where Do We Go Next? USACE to evaluate four alternatives: No action Low-flow restoration Low-flow restoration and sediment remediation with ecosystem restoration Low-flow restoration, combined sewer overflow elimination, and sediment remediation with ecosystem restoration Study scheduled for completion in FY 2012

26 Bubbly Creek?

27 Questions?