How does the Middle Yampa score?

“Hydrology” has been happening in the Yampa River Basin for thousands of years! The term “paleohydrology” is the scientific study of the movement, distribution, and quality of water on Earth during previous periods of history and reminds us to put these data into perspective.

Rivers are naturally dynamic and bank stabilization efforts can often push the problem downstream.

For a deeper understanding of the energy of the river, click on the indicator.

Water quality in streams and rivers across Colorado is regulated by the Colorado Department of Public Health and Safety (CDPHE). Within CDPHE, the Water Quality Control Division (WQCD) monitors and reports on the quality of state waters to prevent water pollution and protect and restore Colorado’s water quality for public health, the environment, and future generations. Water quality standards for metals, nutrients, and physical parameters describe the desired condition of a waterbody and the levels of constituents in the water required to achieve a particular designated use, such as recreation, water supply, aquatic life, and agriculture. Colorado is authorized by the EPA to establish water quality standards, which form the legal basis for controlling pollutants entering waterways.

Side channels and split flows are commonly found along the Yampa River and are an important indicator of ecological health. They are calm, slower-flowing areas of water that give fish and other aquatic species a place to rest away from the higher energy water in the main channel. These secondary channels are especially important as spawning grounds and nurseries for native fish species. These river features are considered when assessing both aquatic connectivity and structural complexity of the river.

When a river is connected to its floodplain, water returns to the river more slowly, extending the flow into drier months, when farmers and ranchers most need it. Where floodplain connectivity is high, seasonal floods can spread out and dissipate their energy before causing too much damage. Additionally, there is evidence to support the claim that connected floodplains are more resilient to wildfires and even contribute to increased precipitation!

The Yampa River supports one of the world’s largest remaining examples of a rare riparian forest type dominated by narrowleaf cottonwood, box elder, and red-osier dogwood. (A few places in Utah, Idaho, Wyoming and Colorado are the only places where this plant community occurs.). Visit The Nature Conservancy’s Carpenter Ranch to experience this valuable riparian forest for yourself.

Channel morphology is not just determined by hydrology and geology, but biology as well!

Plants and animals big and small can actually be drivers of the physical form of a stream (Castro and Thorne, 2019).

For example, riparian vegetation tends to have a stabilizing effect on channel morphology. Beaver change streams by increasing the channel complexity and amount of fine sediment deposition. Amazingly, macroinvertebrates such as caddisfly can be drivers of channel morphology because they reduce the mobility of the sediments along the riverbed. Conversely, macroinvertebrates and fish can also serve to increase bed mobility, due to the disturbance that results when fish forage for a macroinvertebrate meal!

Beaver increase habitat complexity and therefore support biodiversity, but beavers do not eat fish! In fact, they cut trees to form dams and lodges but eat the tree bark or the softer layers of wood underneath, called the cambium layer. Beaver are herbivores that also eat leaves, woody stems and aquatic plants. In the winter, beaver eat from a cache of branches submerged beneath the ice on the muddy pond floor. The cold water keeps the stems fresh and preserves the nutrients.

Macroinvertebrates are amazing little creatures that support a huge food web and can tell us a lot about the water quality of a river. Historically, information on these small animals has been collected irregularly, and there are large gaps in the data set. Through the Yampa River Scorecard Project, Friends of the Yampa is working with local and state partners like Colorado River Watch to fill in the gaps and become a source of ongoing, long-term information about the benthic macroinvertebrate communities in the Yampa River.