Founder and President

Mark Mattson is a prominent environmental lawyer who has spent the last decade building a network of successful community-focused environmental organizations across Canada. His love of water stems from his childhood summers swimming and fishing on Wolfe Island, near Kingston.                    

Born into a family of lawyers in Southern Ontario, Mark grew up with a passion for fairness and individual rights. He has worked in the private, public, and nonprofit sectors over the course of his career. As a prosecutor, first for government and then for NGOs, Mark was part of ground- breaking private prosecutions and administrative cases against major industrial polluters.

After ten years in the courtroom, Mark began to devote more time to developing institutions that will restore and protect watersheds for generations to come. He founded Lake Ontario Waterkeeper in 2001 and remains the organization’s full-time Waterkeeper and President to this day. Mark sits on the board of directors of four Waterkeeper organizations in the U.S. and Canada.

When he transitioned from full-time lawyer to full-time Waterkeeper more than ten years ago, Mark was able to unite his commitment to social justice with his passion for water. He has spent the last decade working to uphold the ideal that each and every person has a right to swimmable, drinkable, fishable water.


Founder and Vice-President

Krystyn Tully has been organizing community events and organizations since her days as a high school student in Oshawa, Ontario. She helped Mark Mattson launch Lake Ontario Waterkeeper in 2001 and serves the organization to this day.

Over the course of the last decade, Tully helped to organize a wide range of fundraising events grantwriting campaigns that helped to raise $2-million for Waterkeeper’s work. She also spearheaded the creation of Swim Guide, a mobile app and website that connects people to clean, local beaches as well as Drink Guide, an app that documents drinking water advisories across Canada. These apps are now used by more than 100,000 people in Canada and the USA.

Since co-founding Lake Ontario Waterkeeper with Mark Mattson in 2001, Tully has written or edited more than 400 articles about water and environmental policy. She has appeared before numerous municipal, provincial, and federal government committees. For four years, she coordinated a mentoring program that connected aspiring lawyers with communities facing environmental challenges. For two years, she was editor and co-host of a weekly radio program. In 2012, she wrote a series of features on beaches for blogTO and became a regular contributor to Huffington Post.

Through Ryerson University’s part-time degree program, Tully has received extensive education in Public Administration and Governance, with a specialization in nonprofit sector management. She was profiled in NOW Magazine’s “Class Action” feature in October, 2012.


Community Outreach Manager

As Community Outreach Manager Allie works to inform and educate individuals, groups, and organizations about LOW and the work we do. Allie answers any questions you e-mail or call with and she helps to tell the stories of the lake. In addition to this work, Allie is responsible for LOW’s volunteer team, maintaining a relationship with our members and promoting events.

Allie joined LOW in June 2009 after completing her degree in Biology and Environmental Science at Trent University. While at Trent, Allie worked for Trent’s marketing and communications department where she assisted with projects including online video content, digital asset management, and Trent University’s virtual tour.



Events and Operations Manager

As Event and Operation Manager, Miriam works on planning fundraising and community events, and helps manage administrative duties. Miriam came to Canada as a young girl, forming a lasting bond with the urban natural spaces she grew up in. She completed a Bachelors degree in Environment and Resource Studies at the University of Waterloo in 2008 and a Masters in Environmental Studies at York University in 2011. She is passionate about social and environmental justice, and their intersections. Her research and past work experiences with community organizations in Toronto have revolved around understanding issues of diversity and inclusion in the context of environmental movements. She loves the outdoors, hiking, and the chance to go fishing – especially when it involves a shore lunch!



Articling Student

Pippa is thrilled to be articling with Lake Ontario Waterkeeper from July 2013 through May 2014. She earned a BA (Hons) from McGill University in History and Anthropology and a JD from the University of Alberta (U of A). While a law student, Pippa was the president of the U of A Environmental Law Students’ Association, VP Internal for the U of A Oil Sands Student Delegation, and active member of the Canadian Association of Environmental Law Students’ Societies. Last year also saw her win the second annual West Coast Environmental Law Twitter Moot.

Pippa has had practical legal experience volunteering for and interning with various public law organizations, including a year long placement with Legal Aid Alberta. She is interested in social and environmental justice and ecofeminism and how inclusive environmentalist values may inform environmental advocacy and law.



Swim Guide Affiliates Coordinator

As Swim Guide Affiliates Coordinator, Gabrielle supports the public and nonprofit organizations that contribute water quality information to the Waterkeeper Swim Guide app and website. Gabrielle also monitors information for 5,000 beaches in Canada, the US, and Mexico to ensure that Swim Guide users have access to up-to-the-minute water quality. 

Gabrielle joined LOW in 2014. She is a Southern Ontario native and grew up on the banks of the Welland Canal. She earned her undergraduate degree from Trent University in First Nations Studies and her Masters in Canadian History from Lakehead University. As part of her research she studied the environmental history of Aboriginal fisheries in Northwestern Ontario.  For the past three years, Gabrielle has volunteered at Israel’s Sea Turtle Rescue and Rehabilitation Centre. There she cared for sick and injured sea turtles, monitored sea turtle nests and hatchlings, and worked to promote the protection of the Mediterranean’s marine environment. 

Gabrielle is an avid open water swimmer and loves her native watershed.  



As Secretary, Tammy provides administrative assistance to the entire Waterkeeper staff. If you call our office or visit, chances are Tammy will be the first person to greet you. 

Tammy has a science  degree from the University of Western Ontario and an Environmental Protection certificate from Centennial College. She has spent 6+ years in the non-profit and environmental sector, engaging communities on local environmental projects. 

Growing up in Mississauga, Tammy has a lot of happy memories walking the ravine system with her family every weekend. It is this deeply rooted connection with water and nature that has shaped her path today. Now as a resident of Toronto, Tammy sees a need for environmental justice and for local residents to reconnect with their water. 



Technical Advisor

Dylan is the in-house technical advisor to Lake Ontario Waterkeeper, dealing with information technology resources and technical projects. Dylan helped to build a variety of Lake Ontario Waterkeeper projects, including, Swim Drink Fish Music, and the Waterkeeper Swim Guide. 

Dylan has been working in the field of information technology for almost 20 years. He was the technology director of one of the GTA's early independent internet service providers and since 1998 has been the Chief Technology Officer of a successful e-commerce company.

Dylan is also Lake Ontario Waterkeeper's in-house photographer and videographer, as well as the pilot of our fleet of unmanned photography aircraft.