The Western Durham Water Quality Monitoring Program 2006 to Gary S Bowen

Transcription

1 The Western Durham Water Quality Monitoring Program 2006 to 2014 Gary S Bowen Presentation to Durham Environmental Advisory Committee November 20, 2014

2 Objective is to improve our understanding of Nearshore Water Quality Role of creeks, sewers, sewage plant Climatic influences (dry and wet years) Lake level changes Lake physics

3 Lake Ontario is changing: Open Lake Phosphorus Trends Overall water quality is reported to be improving in the open water part of the lake Some concerns about the ring around the bathtub Nuisance algae, beach postings, nearshore etc. Area most influenced by land based activities Source: Dove et al. (2009)

4 By monitoring over multiple years and at multiple locations and water depths Comparisons Creeks, Marshes, Embayments, Shoreside, Nearshore and Open Lake

5 Shoreside Wadeable zone of the lake

6 Shallow areas are only accessible by small boat

7 Deep offshore water requires large boat and special sampling equipment Sample bottles labeled and filled with water from surface, middle and bottom Depth profiles Lake conditions determine sampling depths GPS Navigation Samples filtered in the field

8 Western Durham Monitoring Program 2006 investigations designed with input from Environment Canada Surveys were focused on nearshore, inside of 1 kilometer Sewage Plant Rotary Park Paradise Park All samples taken at the surface Two surveys in August

9 Western Durham Monitoring Program 2 boats required Predominantly surface water samples, however samples were taken at depth along the WWTP outfall transect Sampling Locations Duffin Creek Pollution Control Plant Outfall Drinking water Intake Preliminary data ( ) was made available to MOE, who monitored the area in 2008 Part of 2008 International Year of Study for Lake Ontario

10 MOE included this area as part of the 2008 International Year of Study for Lake Ontario

11 Western Durham Monitoring Program One of the most comprehensive nearshore water sampling collection efforts in the Great Lakes In total, there are ~45 SURVEYS and counting Design Re-evaluated: 2011 to 2013 Duffin Creek Pollution Control Plant Outfall OPG Drinking water Intake Water quality under a variety of lake conditions LOBO Survey design is for regional look at water quality, not to track the effluent plume

12 Current program underway and will continue to 2016 Regional coverage: Pickering and Ajax waterfront offshore at depth

13 Duffin Water Pollution Control Plant Daily average loadings from It will be some time before historic levels are seen again

14 Watershed loading estimates We have local watershed P loads: Duffins Creek TRCA and Environment Canada have been working together to estimate landbased nutrient and suspended loadings from creeks/rivers Missing accurate estimates of local stormwater inputs

15 We have benefited from other researchers MOE studies provided understanding of lake circulation that helps us understand our water quality patterns Taken from Figure 4 in: Howell, E.T., Chomicki, K.M., and Kaltenecker, G. (2012) Tributary discharge, lake circulation and lake biology as drivers of water quality in the Canadian Nearshore of Lake Ontario. Journal of Great Lakes Research 38 (S4):

16 We have benefited from other researchers University of Waterloo sampled and modelled the nearshore in 2007 and 2008 MOE Mean Total Phosphorus ( g/l) Rivers Embayments Shoreside Nearshore Background Howell et al., 2012 Makarewicz et al., Grimsby GTA West Howell, E.T., Chomicki, K.M., and Kaltenecker, G. (2012) Patterns in water quality on Canadian shores of Lake Ontario: Correspondence with proximity to land and level of urbanization. Journal of Great Lakes Research 38 (S4): GTA Central GTA East Ajax Coburg TRCA American side of LO Taken from: Leon, L.F., Smith, R.E.H., Malkin, S.Y., Depew, D., Hipsey, M.R., Antenucci, J.P., Higgins, S.N., Hecky, R.E., Rao, R.Y. (2012). Nested 3D modeling of the spatial dynamics of nutrients and phytoplankton in a Lake Ontario nearshore zone. Journal of Great Lakes Research 38(S4): Taken from: Howell, E.T., Chomicki, K.M., Kaltenecker, G. (2012) Tributary discharge, lake circulation and lake biology as drivers of water quality in the Canadian Nearshore of Lake Ontario. Journal of Great Lakes Research 38(S4):

17 Lake physics Frenchman s Bay Storm Drain To go 4 km (Duffins to Carruthers) Duffins Creek

18 UPWELLING NATURAL MIXING EVENTS Can occur during any month - depends on wind and currents DOWNWELLING ***move nutrients naturally***

19 What have we learned? Nearshore is very clean, evident by the percent of surface samples below the lab detection limit Year Alk Cond E Coli (1 per 100mL) NH 3 (50 to 8µg/L) NO 3 + NO 2 NO 2 (2 to 1µg/L) TP (6 to 3µg/L) ph SRP (4 to 2µg/L) TKN SS (0.9mg/L) % 29% 73% 44% 81% 58% % 29% 0% 7% 73% 54% % <1% <1% 10% 63% 31% No samples No samples 26% 50% 88% 54% 25% 7% 32% 96% 72% min 18% <1% 0% 7% 63% 31% max 41% 29% 73% 50% 96% 72% Not an issue of a poor lab detection limits are not an issue for inland lakes, marshes or creeks - very low concentrations in this area of Lake Ontario, so we re pushing the limits - only very specialized labs (university or government) can reach lower limits, but aren t commercial Creates challenges in comparing and contrasting the data Data must be analyzed using methods designed to account for this type of data

20 Regional Monitoring Program APPROACHES OPEN-WATER CONCENTRATIONS - with so many surveys, there is always one graph that will support what you want - look at the overall trends, not individual surveys!!! TOP IS DIFFERENT FROM BOTTOM

21 EAST vs WEST

22 Water Quality Plots by Year and Distance from Shore Total Phosphorus ( g/l) Soluble Reactive Phosphorus ( g/l) Add <1km boxplot Distance from shore (m) Distance from shore (m) Add >1km boxplot Suspended Solids (mg/l) Nitrate + Nitrate ( g/l) Distance from shore (m) Distance from shore (m)

23 Many nutrient sources exist, and buffer rings overlap!

24 Total Phosphorus Sewage Plant Total Phosphorus ( g/l) Upgrades to P removal International Joint Commission objective for open-waters 0 m m m m m Background Detection Limit = 3 µg/l (2008 on) Detection Limit = 6 µg/l (until Oct, 2007) WWTP outfall is not the only Phosphorus source in the region Within 1 kilometre of the outfall, Phosphorus concentrations are approaching background ( < 1 km mixing zone)

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26 MOE STUDY (4-5km) TRCA (3-5km) Includes 3 km and 5 km U.S. STUDY COTTAGE LAKES SIMCOE PROVINCIAL PARK

27 Interactive web mapping tool allows public to explore our results by survey date

28 Project website Sampling design Laboratory analysis Nutrients and bacteria Nutrient sources Nutrient patterns Nutrients over time Influence of currents Lake physics Next steps Compared water quality to other areas More information Optimized this site for key word searches

29 Cladophora is a remerging issue in the Great Lakes August 2014 photo: Whitby Swimming Beach Issue at many locations along Ontario and New York shorelines Even at locations remote from creeks, sewers, and sewage plants We did not study this algae, but we work with a number of experts who are studying Cladophora

30 Expert Opinions on Cladophora Problems in Lake Ontario Facts Nuisance Cladophora re-appeared in Great Lakes only after invasive Zebra mussels Prior to Zebra mussel arrival, Phosphorus controls under Great Lakes Water Quality Agreement were working Zebra mussels filtering activity has been hypothesized to sequester tributary phosphorus in nearshore regions, reducing offshore primary productivity What are experts saying about how to manage Cladophora? There is a lot of disagreement and uncertainty: Controlled by Phosphorus concentrations in the water column--local Sewage Plant is the biggest source. Nearshore shunt (alone) - due to invasive (zebra) mussels (Nearshore shunt) and climate change Photo source: Nearshore shunt + Nutrient levels in whole lake (need to consider inputs from Lake Erie, Niagara River provides 85% of the water coming in to Lake Ontario). Nearshore shunt + GTA Urban gradient (Storm water, Tributaries + Sewage Plants) Algae growing in deep waters in the main lake is controlling variable (food source) mussel biomass and filtering rates--light & bottom phosphorus levels

31 Acknowledgements Regional Municipalities of York and Durham, and Environment Canada for funding and logistical support. Collaborative Scientific and Technical support provided by Ontario Ministry of Environment, Environment Canada, and the University of Waterloo. TRCA field crews for dedicated effort collecting these water samples under very arduous working conditions. Dr. Krista Chomicki, Carolyn Brown, Rick Portiss, and Maryam Nassar for data management, analysis reporting, and project management.