Ocean circulation, sedimentation in the San Juans - compilation of mainstream scientific literature by Dave Hyde -

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1 Ocean circulation, sedimentation in the San Juans - compilation of mainstream scientific literature by Dave Hyde - Salish Sea has 3 principal estuaries SG, JDF,PS San Juan Islands ocean setting uniquely at the cross roads & not part of the Puget Sound Tides, currents, river outflows & bottom water mixing overwhelm local runoff Water quality, sediments & local impacts issues? Decadal trends regional warming, sea level rise, precipitation? This body of scientific literature not yet incorporated into the BAS for the San Juan Cty CAO & SMP

2 Bottom Line Assessment -Directly Derived from Ocean Model Studies- SJC is 98% in the path of a massive SSG circulation system - mixing Pacific seawater, fresh water outflow & effluent of a population exceeding 3.65 million people No measure taken by SJC to mitigate perceived local runoff problems on a general scale will have any effect on marine shoreline water quality Only the Canadians can fix general water quality issues within our coastal waters No local water quality measurement or monitoring effort will produce meaningful information - we are overwhelmed daily by circulating Canadian water No local-scale cause and effect relationship can be established Nothing that is going on in the Puget Sound affects SJC, or is affected by SJC environmental measures Any studies/advice linking Puget Sound issues with SJC are totally inaccurate SJC environmental initiatives for its coastal zones can only make a difference on the few local issues it has -- generally localized upper bays with reduced flushing Considering the mature & tested oceanographic science connecting San Juan Archipelago coastal waters to Canadian circulation, there can be no measurable change to overall SJC water quality from the current CAO or SMP initiatives a focus on spot issues would instead be productive

3 Literature Search Questions What is the connection of SJC marine waters to Puget Sound watershed water quality issues & mitigation initiatives: Ocean circulation connection or just political? What is the current state of Physical Oceanography of SJC waters & relationship to County CAO/SMP initiatives: What is the big picture Can an environmental baseline be established? Can shoreline waters impacts be quantified or measured? Are there specific shorelines where County actions might make a difference?

4 Strait of JDF San Juan Islands

5 SSG & SJA ocean geochemistry cycle

6 Estuarine mixing in the JDF? -Very little! - Puget Sound & Strait of Georgia flows keep to their sides of the highway 12/18/2011 tides Flood IOS interactive tidal model Ebb

7 High energy tides & northern river outflows dominate local circulation! IOS interactive tidal model 9 hour time series, 03/26/ hrs

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9 Vertical mixing in the Haro Strait

10 Boundary Pass Flows 12/18/2011

11 Fresh water Flows into the SSG - Dominates SJA spring/summer circulation & sedimentation - Fraser river & other BC rivers produced ~ 220 cu km FW in 2011, 6-8x PS sources ~ 25% of SG total volume kt avg flow out through SJA into JDF Surface plume in SSG mixed by tidal action at Boundary pass sill & Haro Strait 30 million metric tons of annual particulate outflow 2/3 in suspended fine sediments Local mixing enables bottom water north flow from JDF into SSG Fine sediments deposited in the SJA bays by complex process

12 Stream flow & nutrients from yr2000 WWU SJA survey - Negligible discharge relative to Fraser river -Negligible nutrient discharge relative to bottom water supply

13 Satellite mapping of suspended sediments & chlorophyll

14 Sediment suspension and remixing in SJC channels Data from IOS Johannnessen et al 2006

15 Tidal mixing of Fraser SSG plumes & Island sediments Sills with strong tidal flows Mix sediments throughout water column & scour bottom areas Create sediment deposition fields Boundary Pass sill has created the largest known active seabed Dune field Data from MLML/IOS 2002 bottom imaging sonar survey Same instruments as used in modern hydrographic surveys

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17 What do these seabed maps tell us? -Tides are remixing bottom sediments -Sediments are settling in quieter waters -SJA harbors & bays have a constant influx of sediments via tidal exchange with channels -Plume influx persists from April thru August -Remixing spans all seasons (spring tides) Sediment Geology from core samples

18 Regional long term trends (decadal, not climate change) - local ocean temperature (~0.15 deg C/decade)

19 Summary Findings and Conclusions Local tides create turbulent mixing throughout the Islands shoreline marine zones that constantly bring up bottom water (hence the low temps) This is a good thing, the salty bottom water is the really clean stuff SJC has the best flushed coastal waters in the lower 48 states Rivaled only by the north Maine coast Several local partial exceptions Northern reaches of Orcas East and West Sounds (runoff & reduced flushing) Friday Harbor (high density urban runoff, excellent flushing in harbor, periodic chlorination of WWTP effluent) Above issues aside, SJC coastal zone runoff to the ocean is very rapidly transported out the JDF to the Pacific Ocean This is scientific fact, not a call for less than responsible coastal water management in the San Juan Islands These facts do not support the imposition of extraordinary restrictions buffer zone extensions as proposed in the current CAO & SMP development

20 What can you take away from this Summary? SJA sits in a unique marine setting of high energy tidal flows exchanging JDF bottom waters & seasonal fresh water plumes from the SSG IOS locally provides a world class resource for tidal flow modeling & oceanography Local Sills & Spring tides create wide spread turbulence that mix marine flows & bottom water Neap tides refresh bottom waters from JDF & renew nutrients year-round Natural bottom water nutrients dominate locally, not runoff or even Fraser outflow Renewal time of waters in SJA marine straits & channels is short ~ 1-2 days Most bays & harbors exchange high % volume with channels daily Spring/summer influx from Fraser plumes dominate SJA sedimentation On a multi-decadal trend line SJA & SSG waters are warming slowly Warming rate modulated by PDO predominantly & somewhat by Fraser outflow temps Precipitation increase of 10-25% predicted multi-decadal Fresh water SSG outflows will increase & distribute more evenly over seasons Compelling and extensive scientific literature is available to set a baseline for SJ Islands environmental updates (CAO & SMP)

21 A Selected Bibliography 1. A Model Study of the Salish Sea Estuarine Circulation Sutherland & MacCready (Univ of Wash), Banas (APL UW), Smestead ( NRL) June 2011, DOI: /2011, JPO Observations and modeling of seasonal variability in the Strait of Georgia and Juan de Fuca Masson & Cummins (IOS - Sidney, BC) Journal of Marine Research 62, , The Circulation & Residence Time of Strait of Georgia using a Simple Mixing-Box Approach Pawlowicz, Riche & Halverson (Dept of Earth & Ocean Sciences, UBC Atmosphere-Ocean 45 (4) 2007, , Canadian Meteorological & Oceanographic Society 4. Comparative analysis of Canadian Pacific North Coast & Strait of Georgia marine ecosystems Perry, Crawford, & Sinclair (Fisheries & Oceans Canada) PICES 16 th Annual Meeting, Victoria, 26 October Fraser River Basin Case Study, British Columbia, Canada Calbick, MacAllister, Marshall & Like for the Fraser Basin Council, Dec. 2004