About Onterra

Onterra, LLC is a natural resource consulting firm specializing in lake management planning services.  The firm was created in 2005 by Tim Hoyman, and since then, has worked on over 300 waterbodies in 32 Wisconsin counties.  As of 2020, over 250 lakes in Wisconsin are managed under a plan created with Onterra’s assistance.  Onterra has also worked with many groups on the implementation of their management plans, which include AIS management and monitoring projects, specific diagnostic studies, and continued environmental monitoring.  

Onterra is staffed by natural resource scientists and planners and does not perform herbicide applications or sell aeration systems, mechanical harvesters, or other lake management products.  As a result, Onterra-led management planning projects are objectively created by a staff of experienced ecologists.

Since its start, Onterra has been a strong supporter of the Wisconsin Lakes Partnership and its annual convention, which is the largest citizen-based lakes conference in the US.  Onterra has also worked in partnership with the Wisconsin DNR and US Army Corps of Engineers to conduct important field research.  Onterra staff have presented these results, and others, at many regional and national conferences, and have also coauthored several scientific journal articles.

In 2017, Onterra was honored to receive a Wisconsin Lakes Stewardship Award for our efforts in protecting and restoring lakes.

Onterra, LLC Lake Stewardship Award Video Produced by UW-Extension Lakes


Meet Our Staff

Timothy A. Hoyman

Tim Hoyman is the founder of Onterra, LLC and the firm’s lead aquatic ecologist.  Tim holds a Bachelor of Science in Biology and Chemistry from UW-Whitewater and a Master of Science in Limnology from Iowa State University.    Tim is an experienced aquatic ecologist who has been specializing in lake management for over 20 years in Wisconsin.

Being the lead ecologist, Tim is highly involved with every project Onterra undertakes.  Tim’s primary focus within the company and its projects are in water quality analysis, watershed assessments, modeling, aquatic plant management, and stakeholder participation in the planning process.

Eddie J. Heath

Eddie Heath has been with Onterra, LLC since its creation in early 2005.  Eddie holds a Bachelor of Science in Environmental Science from St. Norbert College and a Master of Science in Environmental Science and Policy from UW-Green Bay.

Eddie has been a member of the Midwest Aquatic Plant Management Society since 2013, served on its Board of Directors in 2016-2017, and currently chairs the Student Affairs Committee.

Eddie currently manages numerous projects within the firm and oversees all aspects of Onterra’s aquatic plant work, including field surveys, data analysis, and management planning.  Eddie is also our lead GIS specialist and is currently developing Onterra’s use of ArcGIS Online to relay current and historical aquatic plant location data to our clients via website-based, interactive map.

Brenton T. Butterfield

Brenton Butterfield began with Onterra on a part-time basis in the spring of 2007 and now as a full-time aquatic ecologist manages several planning projects each year.  Brenton is arguably one of the top aquatic plant taxonomists in the state and performs essential functions in the field and office; including: water quality data analysis, watershed modeling, and report writing.  Brenton holds Bachelor of Science and a Master of Science in Environmental Science and Policy from UW-Green Bay. 

Paul J. Garrison

Paul Garrison joined the Onterra team in 2016. Paul has a Bachelor of Science and a Master of Science in Biology from Montana State University.  Paul worked for over 38 years as a research scientist for the WDNR, retiring in 2015.

Paul’s primary focus at Onterra is paleoecology which he uses to determine long-term changes that occur in lakes.  Paul also provides expertise in water quality analysis, nutrient dynamics, and modeling.

Todd W. Hanke

Todd Hanke started with Onterra as a summer intern in 2009.  He completed his Bachelor of Science in Water Resource Management at UW-Stevens Point later that year and returned to Onterra to complete another internship with the company.  In 2010, Todd was hired on full-time and in 2020 he was promoted to Aquatic Ecologist.  Todd’s primary responsibilities revolve around aquatic plant and AIS control monitoring.  Todd also manages several AIS projects and assists with several planning projects.

Josephine M. Barlament

Josephine “Jo” Barlament began working for Onterra as an intern during the spring of 2016 and has been working on a full-time basis since the spring of 2018.  Jo graduated with a Bachelor of Science in Biology from UW-Green Bay in 2016.  In 2020, Jo was promoted to Lead Field Technician.  Jo is responsible for scheduling and tracking field surveys, overseeing the integration of fisheries information into each of our management plans, analyzing vegetation and water quality data, modeling watershed inputs, and assisting our lake groups with the implementation of their riparian stakeholder surveys.

Andrew M. Senderhauf

Andrew is a 2017 graduate of UW-Stevens Point with a Bachelor of Science in Water Resources.   Andrew was added to Onterra’s permanent staff in the fall of 2018 after completing internships during the summers of 2017 and 2018.  Andrew is a field crew chief leading many field surveys each year.  Andrew is also completing much of our GIS work and assists with water quality analysis, watershed modeling, and fisheries data integration within our plans.

Heather A. Lutzow

After completing an internship with Onterra during 2018, Heather was hired on a full-time basis in 2019.  Heather has a Bachelor of Science in Environmental Science from UW-Green Bay and completes much of our aquatic plant data analysis and assists with water quality and watershed analysis.  Heather is instrumental in the development of many of our grant applications and assists our planning project clients with the development, distribution, and integration of their riparian stakeholder surveys.

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