9/12/2014 O V E RV I E W

Transcription

1 K E E P I N G T H E N E W M I S S I O N R E AC H C L E A N T R A S H & F L O ATA B L E S B M P S T U D Y Russell Persyn, P.E., Ph.D. (SARA) Cris Parker, P.E., CFM (HDR) September 4, 2014 O V E RV I E W» Mission Reach Background» O&M Challenges» Trash & Floatables BMP Study» Recommended Project Implementation» Q&A 1

2 P R O J E C T PAR T N E R S» Bexar County» City of San Antonio» San Antonio River Authority» San Antonio River Foundation» San Antonio River Oversight Committee» U.S. Army Corps of Engineers P R O J E C T G O AL S» Ecosystem Restoration Restore Aquatic Habitat Restore Riparian Woodland 2

3 P R O J E C T G O AL S» Recreational Features 15+ miles hike/bike 9 water edge landings 6 footbridges 4 pavillions P R O J E C T G O AL S 3

4 P R O J E C T G O AL S O P E R AT I O N S & M AI N T E N A N C E C H AL L E N G E S» Balancing Storm Water Conveyance, Habitat Restoration and Recreational Uses» Urban Stormwater Runoff» Trash & Floatables 4

5 B M P S T U D Y O B J E C T I V E» Focus: Control trash & floatables reaching the Mission Reach» BMP measures to incorporate into current Mission Reach construction contract S C O P E O F W O R K» Study Area 5 Major Watersheds» Over 64 Square Miles 5

6 S C O P E O F W O R K» Trash loading analysis» Evaluation of BMP alternatives» Identification and prioritization of BMP candidate sites» Development of project implementation plan» Structural Devices or constructed features that prevent trash from entering storm drain system or receiving waters» Non-Structural Behaviors or actions taken to prevent trash from being generated 6

7 » Structural Trash Control BMPs Inlet Controls Curb inlet screens In-line Controls Continuous Deflector System (CDS) Catch basin bags Baffle box» Structural Trash Control BMPs End-of-Pipe Controls End of pipe cage In-stream/Channel Controls Trash boom End of pipe net Bandalong litter trap 7

8 » Structural Trash Control BMPs Ponds/Basins/Wetlands Constructed Wetland Extended Detention Basin» Non-Structural Trash Control BMPs Regulatory Control Measures» City or County ordinances Public Outreach and Education» Modify public behavior over time Municipal Operations & Maintenance Actions» Direct actions taken by municipalities 8

9 9

10 » Alternatives Analysis SARA jurisdictional/regulatory authority is limited SARA does not own and maintain the storm sewer system» Regulatory control measures» Municipal operations & maintenance» Inlet controls» In-line controls» In-stream/channel controls» End-of-pipe controls» Ponds/basins/wetlands» Public outreach and education 10

11 » Alternatives Analysis In-channel/In-stream Controls and End-of-pipe Controls» Greatest potential for implementation with Mission Reach construction project» Could be installed at or near San Antonio River on SARA or public property I D E N T I F I C AT I O N O F C AN D I D AT E B M P S I T E S» Potential BMP Project Sites Identified Desktop review of GIS data» Large contributing drainage areas» Land availability and accessibility» SARA or publicly owned land Field visits to sites to verify feasibility of BMP implementation 11

12 I D E N T I F I C AT I O N O F C AN D I D AT E B M P S I T E S SIX MILE CREEK OUTFALL I D E N T I F I C AT I O N O F C AN D I D AT E B M P S I T E S» 27 Identified Candidate BMP Sites 12

13 T R AS H L O AD I N G AN A LY S I S» Helped prioritize identified BMP sites» Helped design and cost BMP measures» Computed estimated annual trash loads for each tributary» SARA Staff Observations San Pedro Creek exhibits the highest levels of trash, followed by Concepcion Creek and Six Mile Creek Trash levels are low in Asylum Creek and Riverside Creek T R AS H L O AD I N G AN A LY S I S Litter Generation Rates from Los Angeles River Watershed Trash TMDL Land Use Gallons per Acre per Year Pounds per Acre per Year Commercial Industrial Open Space and Parks Freeways High-Density Single-Family Residential Low-Density Single-Family Residential

14 T R AS H L O AD I N G AN A LY S I S Estimated Trash Load per Area for Tributary Watersheds Watershed Drainage Area (acres) Estimated Annual Trash Load Estimated Annual Trash Load per Acre (gallons) (pounds) (gallons/acre) (pounds/acre) Asylum 1,437 12,900 22, Riverside 1,507 14,900 24, Concepcion 3,722 35,900 58, Six Mile 9,460 88, , San Pedro, including Apache, Alazan & Martinez 12, , , Alazan below Woodlawn Lake 1,592 16,600 26, Apache below Elmendorf Lake 3,274 30,900 51, San Pedro, excluding Apache, Alazan & Martinez Martinez 3,035 36,000 55, ,670 45,600 73, Assumption: Litter rates = trash rates at tributaries Assumption: Westside Creeks below lakes P R I O R I T I Z AT I O N O F C AN D I D AT E B M P S I T E S» Evaluation Criteria Comparison Criteria Weight Criteria C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 Total C1. Location of tributary confluence within Mission Reach C2. Observed quantity of trash in tributary at potential BMP site 1 C3. Observed quantity of litter in watershed C4. Contributing drainage area size to candidate BMP site 1 C5. Computed trash load per area for tributary watershed C6. Construction and maintenance access C7. Property ownership (BMP site and access) C8. Opportunity to implement controls for pollutants other than trash 0 C9. Location of site within watershed C10. Susceptibility to vandalism C11. Dummy Criterion Grand Total Description Weight Rank SARA ownership of site property Accessibility for construction and maintenance Susceptibility to vandalism Drainage area to site Location of tributary confluence within Mission Reach Location of site within tributary watershed Observed quantity of trash in tributary at site Estimated trash load per area for tributary watershed Observed quantity of litter in watershed Opportunity to implement controls for pollutants other than trash

15 SARA ownership of site property SARA ownership of site property Accessibility for construction and maintenance Accessibility for construction and maintenance Susceptibility to vandalism Susceptibility to vandalism Drainage area to site Drainage area to site Location of tributary confluence within Mission Reach Location of tributary confluence within Mission Reach Location of site within tributary watershed Location of site within tributary watershed Observed quantity of trash in tributary at site Observed quantity of trash in tributary at site Estimated trash load per area for tributary watershed Estimated trash load per area for tributary watershed Observed quantity of litter in watershed Observed quantity of litter in watershed Opportunity to implement controls for pollutants other than trash Opportunity to implement controls for pollutants other than trash 9/12/2014 P R I O R I T I Z AT I O N O F C AN D I D AT E B M P S I T E S» Candidate BMP Site Ranking Sum of score of each criterion criteria weight Rank Watershed BMP Site ID Score Criteria Weight San Pedro SPE Six Mile SIX Alazan ALZ Martinez MRT Apache APA Alazan ALZ Concepcion CON Asylum ASY Apache APA San Pedro SPE Martinez MRT Apache APA Alazan ALZ Martinez MRT San Pedro SPE P R I O R I T I Z AT I O N O F C AN D I D AT E B M P S I T E S» Candidate BMP Site Ranking (continued) Rank Watershed BMP Site ID Score Criteria Weight Riverside RIV Alazan ALZ Six Mile SIX Concepcion CON Asylum ASY Riverside RIV Martinez MRT Six Mile SIX Asylum ASY Concepcion CON ,24 26 Six Mile SIX Riverside RIV

16 P R I O R I T I Z AT I O N O F C AN D I D AT E B M P S I T E S» Candidate BMP Site Ranking R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN» Preliminary plans and capital & annual cost estimates developed for top 20 BMP project sites» Mostly in-stream trash booms with cage devices (Bandalong litter trap) Can be installed as part of Mission Reach project Relatively quick installation Little to no site improvements 10 x 41 cage area (largest type) 16

17 R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN 17

18 R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN» Capital and Annual Cost Estimates Total estimated capital cost for 21 BMP Projects = $6.3 million Total estimated annual cost = $1.4 million» Capital costs based on typical unit costs for construction (SAWS, CoSA, TxDOT) and equipment» 2012 values from Bexar County CAD for property/easement acquisition» 20% contingency, 10% soft costs Description Unit Unit Price ($/unit) Site Preparation/Improvements Mobilization (5%) Clearing and Grubbing Excavation 6" Flex Base (Access Driveways) Gate Landscaping seeding Summary of Estimated Unit Costs LS AC $3, CY $20.00 SY $30.00 EA $ SY $1.50 BMP Devices EOP Trash Trap Small Bandalong (w/ 2-10' booms) Large Bandalong 10' x 41' (w/ 2-10' booms) Additional Extended Collection Boom Liftout Baskets HDPE Skirt Rider Poles and Roller Assembly Anchor Freight and Installation EA $60, EA $52, EA $72, LF $ EA $7, LF $35.00 LS $15, LS $10, LS $48,

19 R E C O M M E N D E D P R O J E C T I M P L E M E N TAT I O N P L AN» Recommended Pilot Project Total estimated capital cost for 4 BMP projects = $1.3 million Total estimated annual cost = $262,400 Q U E S T I O N S AN D AN S W E R S Cris Parker, PE, CFM HDR Cristopher.Parker@hdrinc.com One Man s Trash Steven Schauer San Antonio River Authority sschauer@sara-tx.org