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Water Quality Monitoring


Year Round

Through a scientific approach, GCWIN works to monitor environmental health in Grand County.  The information we collect is crucial to ensuring that we protect and improve water quality within the headwaters of the Colorado River.

Currently, GCWIN monitors over 60 sites over five different monitoring programs.  All programs are implemented with robust quality assurance and quality control measures and all data that is collected is made available through GCWIN's online database.


Stream Temperature


April - October


Since 2005, GCWIN has monitored Grand County's streams and rivers for temperature.  Currently, GCWIN has 45 active monitoring sites spread out across the county.  Stream temperature remains a concern particularly in the summer when high temperatures can hurt our valuable cold-water trout fisheries.


GCWIN's temperature monitoring program:

  • Provides a baseline of temperature data in the Upper Colorado and Fraser River Basins

  • Provides information that has been used to support Colorado stream temperature standards

  • Facilitated Grand County's Stream Management Plan

  • Supports operational decisions for water diversion projects




May - October


Since 2008, GCWIN has managed lake clarity monitoring in Grand Lake and Shadow Mountain Reservoir.  Currently, 7 sites are monitored every week from ice-off to ice-on.  The information gathered is used by the Grand Lake Adaptive Management Committee to evaluate how operations of the Colorado-Big Thompson Project can be adapted to improve Grand Lake clarity.

Clarity measurements are taken using Secchi Disks. To better understand measurements, we collect water surface temperature data, document weather conditions, water color, and visual observations on algal condition and recreation potential. 

For more information visit:


Temperature and Electric Conductivity


March - October


What is Electric Conductivity?  Electrical conductivity is a measure of water's ability to conduct electricity, and therefore a measure of its ionic activity and content.  In short, it is an indirect measure of the presence of dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, and iron, and can be used as an indicator of water pollution.

Since 2010, GCWIN has collected stream temperature and specific conductivity data at 6 sites at all of the inflows into the Three Lakes system to support water quality modeling efforts by Northern Water.



River Watch


Year Round


GCWIN is currently seeking volunteers for this program.  Please contact us for more information.


Since 2017, GCWIN has participated in River Watch which is a statewide volunteer water quality-monitoring program operated by the non profit Earth Force in cooperation with Colorado Parks and Wildlife (CPW). The mission is to work with voluntary stewards to monitor water quality and other indicators of watershed health and utilize this high quality data to educate citizens and inform decision makers about the condition of Colorado’s waters.​

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Once per year


Since 2010, GCWIN has been collecting macroinvertebrates (or bugs) to assess the aquatic life health in the Fraser and Colorado Rivers.  The abundance and diversity of macroinvertebrates is an overall indication of stream health.

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