8/18/2014. Presentation Outline. Abbreviations and Acronyms. A Comparison of Stormwater Management Practices in US and Australian Cities

Transcription

1 A Comparison of Stormwater Management Practices in US and Australian Cities International Public Works Congress, Toronto, Canada August 18, 2014 Sujit Ekka, PE, PH URS Corporation-North Carolina Presentation Outline Durham, North Carolina, USA Stormwater Regulatory Framework Stormwater and GIS Services, Public Works Dept. Current Projects Obstacles to Effective Stormwater Management Australia Stormwater Regulatory Framework Melbourne Water Cities of Darwin, Greater Geelong, Kingston Key Highlights of US and Australia Stormwater Practice Abbreviations and Acronyms US Environmental Protection Agency (EPA) Municipal Separate Storm Sewer System (MS4) National Pollution Discharge Elimination System (NPDES) North Carolina Division of Water Resources (NCDWR) Total Maximum Daily Load (TMDL) Stormwater Control Measures (SCMs a.k.a. BMPs) 3 1

2 Durham Bull City City of Medicine Public Works Department, Stormwater Services Stormwater Regulatory Framework Federal Regulations NPDES Permit, Clean Water Act of 1972 State Regulations Falls Lake 40%Total N and 77%Total P reductions New development limits: Total N=2.2 lbs/ac/yr and Total P=0.33 lbs/ac/yr Jordan Lake 35%Total N and 5%Total P reductions New development limits: Total N=2.2 lbs/ac/yr and Total P=0.83 lbs/ac/yr 6 2

3 NPDES Permit Renewal Reporting Requirements IDDE Monitoring and Assessment Water Quality Recovery Plans Industrial Inspections NPDES Permit Public Education and Outreach Outfall Screening Housekeeping and Reporting Durham Stormwater and GIS Services Division NPDES Permit Compliance State Regulations Compliance Stormwater Utility Billing Infrastructure digital mapping 8 Durham PWD and Stormwater Division Water Quality Infrastructure Public Works Department Stormwater & GIS Services (93 FTEs) Watershed Planning & Implementation Development Review Maintenance and Street Cleaning (50 FTEs) GIS &SW Billing (13 FTEs) 3

4 Stormwater Infrastructure Group Design and construction management Drainage projects within City rights-of-way and City property Private property drainage assistance Floodplain management - Durham recently approved by Community Rating System of National Flood Insurance Program Aging Infrastructure Storm Pipe Failure Water line collapse Pavement failure Emergency Repair $175,000-Construction $175,000 and five weeks later.. 4

5 Stream bank erosion Trail built in 2010 Increased runoff, oxbow channels Hazard for public and infrastructure Failing Infrastructure Temporary Stabilization-$50,000 Long-term solution-$900,000 Water Quality Group Collecting ambient water quality sample Field measurements of DO, Turbidity etc Monitoring data available: Secchi Depth at Falls Lake Water Quality Group Vehicle Washing Compliance Program Benthic Monitoring at Goose Creek Ellerbe Creek Watershed Compliance Demonstration Weekend patrol locations Data used to evaluate health of aquatic life as an indicator of water quality 5

6 Green Infrastructure Pilot Project Rain Catchers Low Impact Development Retrofit Project Two years 230 practices Clean Water Management Trust Fund-$242,000 City Match-$194, 000 Key Question: Will aggressive LID implementation produce measurable improvements in water quality? Green Infrastructure Pilot Practices Rain garden Cistern Downspout disconnection Other Green Practices: Trees Native plantings Green Infrastructure Pilot Project Reverse Auction Strategy to engage stakeholders 80% zero dollar bids 6

7 Watershed Management and Implementation Plan Developed for streams on 303(d) list or a TMDL Assessment of existing watershed conditions Model loads under current and future land development scenarios Determine effective pollution reduction strategies Ellerbe Creek Watershed Plan Approx. 37 sq. mi. (half within City limits) Drains to Falls Lake (drinking water supply) and the Neuse River 303(d) List for biological impairment WMIP completed in 2010 $1m Implementation cost Approx. $370 million Contracting with local non-profits 7

8 Regulatory Challenges State Nutrient Sensitive Waters Strategies: Neuse River: N reduced by 30% Jordan Lake: N reduced by 35%, P by 5% Falls Lake: N reduced by 40%, P by 77% Aging Infrastructure Limited space in developed urban Cities Entire City on Triassic basin Clay soils, low infiltration Economic feasibility and limited resources Unstable Streams-sediment production Local 303(d) Issues Dissolved Oxygen, Copper, Zinc Local TMDLs Fecal Coliforms Turbidity Stormwater Management in Australian Cities 23 Regulatory Framework EPA-State Agency Mid-90 s stormwater era Victorian Stormwater Initiative (BMP guidelines) First major national Stormwater Initiative-2000 No NPDES permits or TMDLS 8

9 Darwin Rainfall Darwin-Annual~65 in January~16 in. Sydney Melbourne Darwin, Northern Territory Population-130,000 (2011) Area-114 square kilometers Stormwater Infrastructure ( ) 348 km of stormwater pipes and 11,000 pits 16 km of open channels 25 gross pollutant traps Experienced rapid population growth and resulting impervious cover ( ) Darwin s Challenges Too much water- Q20 events not uncommon (Typ. design-q1/q5) Capacity issues Infrastructure-Pipes and Pavement 9

10 Asset Management Plan IPWEA-LTFP Model So what is different in Darwin? So what is different in Darwin? Kerb inlets So what is different in Darwin? Gross pollutant traps 10

11 Bondi Beach, New South Wales City of Greater Geelong, VIC 1,600 km SW pipes and 54,000 pits Gross pollutant traps at major outfalls Contract for Sucker Trucks 11

12 Drinking Water, Wastewater, Stormwater Stormwater Strategy ( ) with Victoria State Govt. Waterways and drainage fees Budget: $234m -$145m (capital)+$89m (operating) $8m-stormwater quality capital projects $25m-stormwater quality operating expense Support for local government, O&M, Grants Population-147,000 Area-93 sq km Green Infrastructure Practices 12

13 Original Raingardens ( ) Concept plan 13

14 Recent Raingardens Planting by City Parks Department Raingardens + Traffic Calming Raingardens + Traffic Calming 14

15 Lessons Learned: Kingston s Green Infrastructure Capacity Building- developers, City departments, local residents Engaging the frontline maintenance staff Holistic design: Civil, Environmental, Social Small-scale retrofits not cost-effective for treatment Key Stormwater Practice Features Durham, NC Australia Federal Regulations Stormwater Utility Fees Falls Lake Nutrient Reduction Goals (77% phosphorus) Ambient and Biological Monitoring Program State-level Regulations Asset Management Plan Incorporating climatic variability in design Gross pollutant traps at major outfalls Acknowledgments 15

16 Sujit Ekka, PE, PH Senior Environmental Engineer URS Corporation-North Carolina Morrisville, NC, USA Ph:

17 Abstract title: A Comparison of Stormwater Practices in US and Australian Cities Authors name(s) and organisations: Sujit Ekka, Senior Environmental Engineer, URS Corporation-North Carolina Author who will present at the Conference: Name: Sujit Ekka Organisation: URS Corporation-North Carolina Address: 1600 Perimeter Park Dr, Suite 400, Morrisville, NC, USA Phone: Fax: sujit.ekka@urs.com Key word description of the abstract: stormwater; water quality; watershed; nutrients; pollution; infrastructure; asset management Abstract: The City of Durham, North Carolina, USA is situated along a ridge line and drains to two different water-supply reservoirs: Falls Lake and Jordan Lake. Most Durham streams originate within the city and thus act as a primary conveyance for stormwater runoff from the city to these reservoirs. Consequently, Durham faces stringent surface water quality regulations. For example, a 77% reduction in phosphorus and a 40% reduction in nitrogen levels from baseline loads are required in the Falls Lake watershed. Recent watershed plans developed for three of six city watersheds indicate a funding need in excess of one billion USD to implement conventional stormwater control measures (SCMs) and restoration of degraded stream channels. Water quality projects are constantly competing with the aging stormwater infrastructure of the city for the funding generated by the stormwater utility. As science and regulations continue to evolve, Durham is proactively seeking to learn, evaluate, and implement innovative and cost-effective stormwater management practices from local and international communities to meet the demands of both stormwater conveyance and treatment. The goal of this study was to learn and evaluate effective stormwater practices from Australia, a leader in urban stormwater management. Many American cities like Durham and Australian cities like Darwin and Melbourne face similar stormwater management challenges, including poorly draining soils, increasing populations, and rapid urban development. Structured interviews and informal discussions with Australian stormwater practitioners were used to collect information about their stormwater programs and innovative approaches for water quality and infrastructure management that have been successfully implemented. Site visits in August 2013 included the Institute of Public Works Engineering Australasia (IPWEA) conference in Darwin, the local City Councils of Darwin, Sydney, Kingston, Greater Geelong, as well as Melbourne Water, the agency that manages Melbourne s water resources. Lessons learned from this study include: using simple techniques such as installing gross pollutant traps at major pipe outfalls, stormwater harvesting and reuse, cost-effectiveness of stormwater treatment using centralized water quality devices, engaging frontline maintenance staff, and development of an asset management program for prioritization of capital improvement projects. The observations from this study provided a benchmark for Durham s existing stormwater program and an insight into different approaches used for stormwater management outside the United States. This unique opportunity for knowledge exchange in the areas of stormwater regulations, conveyance, and treatment options was made possible by the International Jennings Randolph Fellowship sponsored by the American Public Works Association, the Eisenhower Institute at Gettysburg College, and IPWEA. Objectives: By attending this session, participants will be better able to: 1. Identify major differences in stormwater management practice in US and Australian Cities 2. Compare their stormwater programs with the Cities discussed in presentation 3. Implement different stormwater practices for their unique challenges and programs