1 / 24

The Orange County Water District Riverbed Filtration Pilot Project

The Orange County Water District Riverbed Filtration Pilot Project. Jason Keller 1 , Michael Milczarek 1 , Greg Woodside 2 , Adam Hutchinson 2 , Adam MP Canfield 2 , Robert Rice 1. 1 GeoSystems Analysis, Inc 2 Orange County Water District.

stacy-potts
Télécharger la présentation

The Orange County Water District Riverbed Filtration Pilot Project

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Orange County Water District Riverbed Filtration Pilot Project Jason Keller1, Michael Milczarek1, Greg Woodside2, Adam Hutchinson2, Adam MP Canfield2, Robert Rice1 1GeoSystems Analysis, Inc 2Orange County Water District

  2. Recharges groundwater basin using Santa Ana River (SAR) water and other sources of water • Over 1,000 acres of surface spreading basins • Average recharge of 230,000 acre-ft/yr • SAR flow comprised of tertiary-treated effluent and stormwater • SAR water quality: • Total Suspended Solids (TSS) varies from 5 to 400 mg/l • Total Organic Carbon (TOC) typically 5 to 10 mg/l • Spreading basin performance declines in exponential fashion due to clogging • Want to improve performance and recharge volumes Orange County Water District

  3. Riverbed Filtration System Pilot Project Objectives • Evaluate riverbed filtration technology to treat SAR water • Design pilot scale riverbed filtration system • Want a shallow collection system to induce recharge • Want low tech, low cost • Construct pilot project in SAR off-river channel • Evaluate potential long-term performance • Monitor: • Clogging rates • Influence on groundwater system • Shallow water level response • Increased recharge rates with filtered water

  4. Santa Ana River Channel Off-River Channel

  5. Pilot System Design • Design for 10 cfs (4,500 gpm) • Guided by two-dimensional model (HYDRUS-2D) • Variable depth and spacing of lateral drains • Foulant layer incorporated to evaluate formation of surface clogging • Pipe flow capacities calculated using Manning’s equation

  6. Model Results • Deeper lateral placement depth increases system capacity • Lateral drain length needed are similar at 80 and 160 ft spacing • Desaturation increases as lateral spacing decreases

  7. Pilot System Design • 6 inch diameter drains carry substantially less flow • Reduced footprint with 80 ft spacing vs 160 ft spacing • Gain in efficiency with depth reduced due to added cost for deeper excavation and installation • Pilot system built using 8 inch diameter lateral drains at 80 ft spacing and 5 ft bgs

  8. Pilot Project Monitoring • Monitoring system to evaluate riverbed filtration system performance • 13 Monitoring Wells and piezometers • Temperature at 1, 6 and 10 ft bgs in selected wells • Stream flow gaging • Flow in – Flow out = GW recharge and drain capture (transmission loss) • Bi-weekly samples of raw source water and riverbed filtration system effluent collected and analyzed for water quality • Percolation testing using raw water and riverbed filtration effluent to evaluate percolation decay

  9. Pilot Study Results

  10. Water Quality • Riverbed filtration significantly improved water quality • Reduced TSS and turbidity by >99% and 96% • Decreased TOC, TKN, iron, and manganese by 50% or greater • Riverbed filtered water quality significantly better than other treatment technologies evaluated • Cloth filter, flocculation-sedimentation, dissolved air flotation, ballasted sedimentation

  11. Percolation Decay • Percolation rates 50% of initial percolation within: • Raw water ~ 7 hours • Riverbed filtered water ~ 58 hours • Air entrapment during early period of riverbed filtration column.

  12. Inlet Surface Flow and Pumping Rates

  13. Phreatic Surface Depth

  14. West East

  15. North South

  16. Pumping and Phreatic Surface Summary • Under no-pumping conditions, unsaturated zone exists • East side of drain system less productive than west side • Water from west supplying east laterals • Strong hydraulic gradient to north • Phreatic surface depths deeper after pumping than prior to pumping • Pumping capacity responsive to surface water flows • Maximum Pumping Capacity • Test Period 1 (w/out L-berms) = 1,350 gpm • Test Period 2 (w/ L-berms) = 2,000 gpm • 30% - 40% of target collection rate (4,500 gpm)

  17. Transmission Loss and Groundwater Recharge

  18. Conclusions • Riverbed filtration significantly improves water quality and percolation performance • System performance dependent on surface water flow rates and depth • Maximum pumping capacity of: • 1,350 to 2,000 gpm • 30% - 40% of target collection rate • Lower than expected groundwater elevations • Strong south-to-north gradient reduced system efficiency • Drainfield east of the collection vault was less productive than west of the collection vault • Drain system induces infiltration during pumping and most of water collected from induced infiltration

  19. What can you say to others that may want to try this? What did we learn? Future Studies • Surface clogging may have contributed to a reduction in induced recharge • Longer term study required to evaluate surface clogging influences • Treatment options • Effective surface water and groundwater depths • System optimization • System expansion planned

  20. THANK YOU!

More Related