Mountain Meadow Restoration

American Rivers is working in California to ensure the green infrastructure benefits of mountain meadows are fully maximized and restored.

Through funding from the Bella Vista Foundation, Sierra Nevada Conservancy, and California Department of Water Resources (DWR) American Rivers is working with multiple partners on a comprehensive Sierra Mountain Meadows Restoration Program. The overall goal of this program is to demonstrate and validate restoration as an innovative approach to improve water quality, in-stream habitat, and water storage capacity.  Objectives in support of this goal include:

• Working with local watershed groups, federal and state agencies, and private property owners to restore meadow habitat in the Sierra;
• Develop a standardized monitoring methodology to determine the impact of restoration that can be applied across meadows;
• Quantify the benefits of meadow restoration in terms of flood reduction, groundwater storage, water quality and habitat;  
• Build capacity in the Sierra for meadow restoration through training and outreach;
• Analyze a range of meadow restoration methods and management approaches and provide recommendations on where, when and how they might be implemented;
• Develop and apply a methodology for prioritizing meadow restoration in the Sierra;
• Develop demonstration projects that incorporate climate change impacts and future hydrology in restoration design; and
• Work with tribal interests to ensure that cultural and spiritual aspects of meadows are integrated into restoration designs.

Benefits of Meadow Restoration

If you spend time hiking in the Sierra Nevada, there’s a good chance that you will find your way to a mountain meadow. In total, meadows occupy a fraction of the Sierra landscape, but their beauty and stark contrast to the surrounding forest make them favorite destinations. One need only step from dense conifers or granite outcroppings to a bright oasis of grasses and wildflowers to know that mountain meadows are hotspots of biodiversity and havens of distinction. Ecologists and hydrologists confirm this instinct: Sierra meadows provide many critical ecological functions.

Mountain meadows occur at hydrologic convergence points in a watershed – that is, areas that encourage sediment to be deposited and water to collect, resulting in high water tables. Thus, meadows represent areas of high moisture availability in what can be an otherwise water-limited landscape. This availability of water in combination with other factors, including shade and lower temperatures during the summer, a greater supply of food due to higher plant productivity, and special plant structures such as willow thickets, make mountain meadows key habitat for Sierra plants and wildlife.

Figure 1.  Diagram of a healthy meadow system with naturally meandering creek supporting native fish, lush wetland vegetation, healthy soil and high levels of groundwater which recharges streams during drier months and creates rich biological diversity. Click here or on the image for a larger version.

Figure 2. Diagram of a degraded meadow system with a deeply eroded stream directing snowmelt quickly downstream, and drawing down meadow water tables resulting in drier vegetation (e.g. sagebrush).  Little habitat exists for meadow species when there are streams with warmer water and periods of lower or no flow. Click here or on the image for a larger version.

River scientists are beginning to collect data that suggest that mountain meadows play a critical role in the watershed by acting as natural reservoirs and natural filters. A healthy meadow river is connected to its floodplain, which means that when flooding occurs, the river overtops its banks and spreads over the plain. This action slows the water, giving it a chance to soak into the ground. In essence, mountain meadows act as giant sponges.  The natural capacity of a meadow to soak up floodwaters and store them in groundwater is similar to the function of a human-made reservoir.

During the dry summer months the filtered and stored water is slowly released back into the stream or river. Streams filled by groundwater have cooler temperatures because groundwater remains cool relative to the stream. By providing stored groundwater over a long period of time, not only do meadows help lower water temperatures, they also increase dry season flows downstream. This cool, late summer water supply can be critical for many species of native fish and other aquatic life.

There is also initial evidence to support the idea that meadows act as natural filters, thereby protecting water quality. Currently, sediments are ranked as the number one pollutant of surface waters in the United States. Excessive sediments cause problems for aquatic life, drinking water treatment plants, industry, navigation, and other uses of the resource.

In one project in the Feather River watershed in Northern California, restored meadows showed a 17.5 percent reduction in annual sediment in rivers and streams. This in turn reduced the amount of sediment in downstream reservoirs, thereby maintaining water storage capacity in the reservoirs. Not only can healthy meadows potentially serve as natural reservoirs, they can also help retain the designed storage capacity – and flood-control and hydropower benefits – of man-made reservoirs.