State of the Lake

State of the Lake Report 2016

Executive Summary

Portage Lake has been managed over the past eight years with goals of identifying and reducing the presence of exotic species throughout the Portage Lake watershed, tracking plant trends, improving water quality readings and protecting Portage Lake into the future. The following report breaks down the specifics of the previous management, the management of the 2016 season and the need for future management. In 2016, just over 21 acres of EWM, Phragmites, Purple Loosestrife and Narrow lead cattails were controlled via chemical control methods. Extensive lake mapping, vegetation mapping and water quality testing was also performed. The abundance of healthy native plants in Portage Lake increases the long term stability of the lake. While some water quality parameters have maintained themselves with little change over the years, other parameters have shown some fluctuations. One of the most important parameter to test is Total Phosphorus and in 2015 and 2016, all lake and shoreline basin samples came back below recent years, showing a decline and a very positive outlook for Portage Lake. Some of these fluctuations in other parameters include showing that the tributaries around Portage Lake are bringing excess nutrients into the lake. This information is vital in determining the areas within Portage Lake that need to be focused on reducing nutrient loading to help reduce the productivity in Portage Lake. The ability of Portage Lake to produce algae and aquatic plants is directly related to the overall health and use of Portage Lake. While the main goal of the management is to protect the long term ecological health of the lake, it is also important to protect the recreational, aesthetical and financial aspects of the lake as well. All of these factors play into the management efforts on Portage Lake which need to be continued into next season.  Portage Lake was selected to be a sampling lake in PLM’s DNR Grant study in 2015. PLM has partnered with Michigan Tech University in a 3-year study to genetically test milfoil plants to determine the plant response to various chemical herbicides. This exciting study is still underway but should assist with management decisions and the direction of the program in the future.

State of the Lake 2015 – Portage Lake Annual Lake Management Report

State of the Lake 2014 – Portage Lake Annual Lake Management Report

State of the Lake 2012 – Portage Lake Annual Lake Management Report

State of the Lake 2011 – Portage Lake Annual Lake Management Report

State of the Lake 2010 – Portage Lake Annual Lake Management Report

State of the Lake 2009 – Portage Lake Annual Lake Management Report
Appendix 2009

Water Testing

State of the lake summary Herb Lenon 2016

Summary of 39 Years of Water Quality Data

State of the Lake 2015 Herb Lenon Summary

Carole Lembi – Why Aquatic Herbicides Affect Aquatic Plants and Not You!\

State of the Lake 2013 Presentation

Swimmer’s Itch

Swimmers Itch Proposal 2016-shortform

Swimmers Itch Survey Description 2016