A Runoff Science long-run series, which will pair citizen science observations and sampling of water bodies with an epic adventure. Each set of observations is designed to be completed in less than 5 minutes, allowing enough time for the group to refuel and regroup before continuing on the trail. These runs are for any outdoor-loving trail runners who might want to learn more about their natural environment and ways they can protect it.
As an Auburn-based organization, Runoff Science is excited to kick off with a focused investigation of the American River watershed in the FlowPath Series. These group long-run adventures are each focused on a portion of the watershed, gradually moving toward the headwaters. However, through the entire series, runners will gain a holistic perspective of the watershed and how the interconnected rivers, tributaries, and lakes all serve a critical role in managing the quantity and quality of water transported throughout the region.
Dwindling mountain snowpack and increased summer temperatures can significantly alter river flows and water temperature throughout the American River system – threatening downstream habitats for cold-water native fish and accelerating the growth of bacteria and algal blooms. Additionally, hot and dry conditions in the upper watershed can exacerbate wildfire risk and increase erosion-driven transport of sediment and organic carbon from terrestrial sources. To measure these climate-related impacts, this series will focus on the following analyses outlined in our sampling protocols:
- Visual assessment of river or stream flow
- Visual assessment for presence of algae
- Water temperature
- Water pH
- Water clarity (turbidity and light absorbance)
- E. coli and total coliform
- Dissolved organic carbon
Ridge to River
When: June 20, 2026 at 8:00 am
Where: Michigan Bluff, CA
This run will take you deep into the canyons of Tahoe National Forest. We’ll run an out-and-back along the Western States 100 course between Michigan Bluff and Swinging Bridge, stopping to make observations at Eldorado Creek and the North Fork of the Middle Fork of the American River. Total distance is estimated to be between 18 and 20 miles.
Talus & Tributaries
When: July 19, 2026 at 8:30 am
Where: Kyburz, CA
This run will begin at Wrights Lake Campground near the South Fork of Silver Creek (a major tributary that supplies the South Fork of the American River). We’ll follow Wrights Lake to Twin Lakes Trail, before climbing up to make observations at several alpine lakes. We’ll follow Twin Lakes Trail back to Wrights Lake Campground. Total distance is estimated to be between 11 and 12 miles. Please note, this will be the most sampling-intensive run in the FlowPath Series.
Summit the Source
When: August 15, 2026 at 8:30 am
Where: Olympic Valley, CA
This run will start along the legendary Western States 100 course, where we’ll run from Palisades up to the Escarpment and locate the headwaters of the North Fork and Middle Fork of the American River. We’ll then follow Granite Chief Trail back to the start. Total distance is estimated to be between 13 and 14 miles.
To understand FlowPath Series observations within the broader spatial context of the American River Watershed, please see the map below. The red shaded polygons outline the watershed boundaries. Each FlowPath running route is shown in purple. Prospective locations for collecting citizen science observations are indicated with black markers.