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.
Clicke Here to View: 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 coauthored research papers and presented findings at regional and national conferences, specializing in the planning and monitoring of aquatic invasive species management. Eddie is active in the Midwest Aquatic Plant Management Society, formerly serving on its board of directors and chairing the Student Affairs and Government Affairs Committees.
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 Onterra’s lead GIS specialist and recently expanded Onterra’s use of ArcGIS Online to relay current and historical aquatic plant location data to our clients via website-based, interactive map.
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 joined Onterra as a summer intern in 2009 and, after earning a Bachelor of Science in Water Resource Management from UW–Stevens Point, returned for a second internship. He was hired full-time in 2010 and promoted to Aquatic Ecologist in 2020. Todd leads and manages numerous projects, with a focus on aquatic plant management and protection.
Ryan M. Flynn
Ryan Flynn began as an Onterra intern in 2020 and returned in 2021 after completing the Treehaven field studies program. In 2022, he interned with the Minnesota DNR collecting stream data across multiple watersheds. After earning a Bachelor of Science in Fish and Water Resources (Hydrology Option), Ryan joined Onterra full-time in 2023 as an Aquatic Field Technician and has since advanced to Lead Field Technician, overseeing scheduling and logistics.
Samuel C. Dodge
Sam Dodge interned with Onterra from 2022–2023 before joining full-time as a field technician in 2024 after earning a Bachelor of Science in Environmental Science from St. Norbert College. Sam plays a key role in field data collection and has expanded his responsibilities to lead the administration of stakeholder surveys, GIS mapping, and technical report preparation.
Kaylee R. Greenwood
Kaylee Greenwood joined Onterra in spring 2025 after earning a Bachelor of Science in Water Resources from the University of Wisconsin–Stevens Point. As a field technician, Kaylee spends much of the open-water season conducting aquatic plant surveys. During the winter months, she compiles and analyzes data for use in reports, management plans, and other project deliverables.
Madeline D. Hetland
Madeline Heltand recently joined Onterra after earning a Bachelor of Science in Fisheries and Water Resources (Soil Science Minor) from the University of Wisconsin–Stevens Point. As an undergraduate, she gained experience with UW–Trout Lake Station, Oneida County Land and Water Conservation Department, and UW–Extension Lakes. Madeline will begin her career at Onterra with fieldwork in spring 2026.