1. Developing Green Stormwater Design Solutions For UIC Compliance Presented by: Adam Zucker PE, CWRE 819 SE Morrison Street ● Suite 310 ● Portland, Oregon 97214 ● 503.274.2010 ● www.vigil-agrimis.com

2. Underground Injection Control - A federal program under the Safe Drinking Water Act that regulates the injection of fluids into the ground Purpose: To protect groundwater from contamination What do we mean by UIC?

3. UIC 101 – History Of Injection Wells Early Injection - Injection of water to extract salts was documented in China around 300 A.D. and in France in the 9 th Century

4. UIC 101 – History Of Injection Wells 1930s - Oil and Gas Extraction 1940s - Oil refineries begin to inject wastes into ground 1950s - Chemical companies begin injecting industrial waste into deep wells

5. UIC 101 – History Of Injection Wells 1960s - Deep well injection causes earthquakes in Colorado - 1 st documented case of drinking water contamination 1970s - Wastes spilling out of an abandon oil well traced to an injection well used by a pulp mill some distance away -Congress passes the Safe Drinking Water Act - 1974

6. UIC 101 – Regulations 1980s - Federal UIC regulations are passed ◦ Define 5 classes of injection wells - Washington Department of Ecology (DOE) and Oregon Department of Environmental Quality (DEQ) delegated the authority to administer the UIC program - 1984

7. UIC 101 – Regulations State UIC enforcement responsibilities - Primacy

8. UIC 101 – Classes of Injection Wells Class I :Deep injection wells for municipalities and industries (549 wells) Class II :Oil and Gas production (143,951 wells) Class III :Mineral Extraction (18,505 wells) Class IV : Shallow storage of hazardous and radioactive wastes. Banned in 1984 (32 sites) Class V : All other injection wells (400,000 to 650,000 wells) well inventory numbers based on EPA data

9. Several subcategories for Class V wells Septic Systems Groundwater Recharge Heating and Cooling Geothermal Stormwater Disposal UIC 101 – Class V Wells

10. Injection Well Sump Soakage Trench French Drain Seepage Pit Drainfield Soakaway UIC 101 – Class V Stormwater Wells

11. …but for this presentation we generally mean Drywells

12. UIC 101 – Drywells

13. UIC 101 – Wells

14. UIC 101 – Back to the Regulations - In 1999 Federal regulations for Class V UICs are revised/clarified -States begin to revise their rules and adopt the following general requirements: ◦ Must be registered ◦ Have no impact on water Quality ◦Meet all other state and federal requirements ◦ Stormwater only; runoff minimized ◦ No other disposal options ◦Isolated from Drinking water sources ◦ No soil or groundwater contamination ◦ Not deeper than 100’ AND adequate groundwater separation ◦ Pretreatment and spill prevention

15. Generally requirement: Groundwater Separation Requirements The bottom of the drywell should be at least 10 feet above the groundwater table.

16. USGS Groundwater Study - 2008

18. How to deal with the groundwater vertical separation requirements? - Connect into a piped stormwater conveyance system - Modify the existing drywell - Surface Infiltration – LID and Green Streets Sorting out UIC compliance

19. Connecting to an Existing Storm System

22. Utility Conflicts

26. Retrofitting Existing Drywells

33. Connecting to an Existing Storm System

36. Retrofitting Existing Drywells

37. Determining hydraulic capacity of drywell retrofit - Drainage basin area - Design storm - Subsurface soil conditions - Capacity tests

38. Retrofitting Existing Drywells

40. Surface Infiltration - Green Street / LID

49. -No longer an overflow to storm sewer system -Space constraints; limited right-of-way - Capturing all the runoff at intersections - Facility Longevity - Be conservative and provide redundancy Surface Infiltration - Green Street / LID Design Challenges and Concerns

50. Questions 819 SE Morrison Street ● Suite 310 ● Portland, Oregon 97214 ● 503.274.2010 ● www.vigil-agrimis.com