Critical Lands & Natural Resources

Foys Bend

What are Critical Lands?

Critical lands are ecologically significant areas that provide clean water and wildlife habitat, as well as recreation opportunities. Lands critical for maintaining water quality in Flathead Lake, such as vegetated streams and river banks, floodplains and wetlands, often serve as the “kidneys of the lake.” When left in a natural state, these areas provide a buffer zone that filters out nutrients and other pollutants before they reach the water.


Wetlands are inundated or saturated by surface or groundwater for most or part of the year.
They filter nutrients, sediments and pollutants and help maintain clean water. Wetlands also provide habitat and food for fish and wildlife. Some examples of wetlands include freshwater wetlands, sloughs (old river channels), springs, swamps, prairie potholes, marshes, bogs, and fens. Learn more about wetlands.

Riparian Corridors

A riparian corridor is a unique plant community near a body of water such as a stream, river, or lake. Vegetation along rivers helps absorb nutrients, sediments and pollutants, and provides habitat for fish and wildlife. It can also help prevent bank erosion. Cottonwood trees are indicators of healthy riparian areas. Other plants associated with riparian areas include willows, dogwood, alder, sedges, forbs, and cattails. 70% of migratory bird species use riparian habitat during migration. Learn more about riparian corridors.


Floodplains store water and slow water during floods which helps prevent or reduce damage. They also filter out nutrients from stormwater and flood water which helps keep water in rivers clean. Floodplains are among the most biologically diverse wildlife habitats. Floodplains have rich agricultural soils. Learn more about floodplains.

Shallow Aquifers

Shallow groundwater or aquifers are often connected with a river and its floodplain. The shallow alluvial aquifer found between Columbia Falls and Kalispell and west of the Flathead River, known as the Evergreen Aquifer, is a series of complex underground channels connected to the river. Water flows relatively rapidly between the Flathead River and the shallow aquifer and hosts a complex and interesting array of aquatic life. The aquifer plays an important role in keeping the river and Flathead Lake clean. Learn more about the Evergreen Aquifer and shallow groundwater.

Why are Critical Lands important?

Riparian corridors, floodplains, wetlands, and shallow groundwater areas provide many benefits, including:

Clean Water

Critical Lands:

  • Filter and take up nutrients, such as nitrogen and phosphorus, and other pollutants, such as pesticides, from stormwater runoff that might otherwise enter a river or lake.
  • Provide soil stability that can help prevent erosion.

Flood Control & Groundwater Recharge

Critical lands:

  • Slow water flow, which can prevent flooding and bank erosion.
  • Store water during floods and help replenish groundwater aquifers and wells.

Wildlife Habitat

Critical lands:

Provide important habitat and food for fish and wildlife, including waterfowl, bald eagles, deer, river otter, and fish.

Recreational Opportunities

Critical lands:

  • Frequently have high scenic qualities and provide opportunities for hunting, fishing, boating and bird watching.
  • River corridors are also culturally and socially significant to native people who traditionally camped, hunted and fished along the rivers and lakes.
  • Conserving critical lands will help keep our waters clean and our landscape beautiful.

The Critical Lands Project

The Critical Lands Project is a collaborative effort led by the Flathead Lakers and involving representatives from federal, state, tribal and local agencies and organizations to identify, protect and restore lands critical to the quality of Flathead Lake and its tributaries. See Saving Critical Lands for more information.

Threats to critical lands

Some examples of threats to critical lands include bank erosion and collapse, pollution, loss of habitat and farmland due to incompatible development, introduction of exotic plants and animals, and removal of vegetation near streams, rivers and wetlands.

Critical Lands identification

Critical Lands Project partners identified existing riparian vegetation along the Flathead River, wetlands and sloughs, the shallow alluvial aquifer (also known as the Evergreen Aquifer), and the north shore of Flathead Lake as critical lands and a high priority for conservation. The Critical Lands Status Report summarizes critical lands in the North Flathead Valley (see page 9 in the report to read about specific areas).

Map of the Northern Flathead Valley [ADD]

These lands support nesting habitat for bald eagles, osprey, Canada geese, waterfowl, upland game birds, great blue herons and double-crested cormorants.

Seventy percent of migratory bird species use riparian habitat during migration. The Flathead River corridor also provides some of the best habitat in Montana for white-tailed deer, beaver, river otter, muskrats, and mink.


2002 Critical Lands Status Report
2002 Workshop Report
2002 Workshop Appendices
2004 Critical Lands Status Report Update
2004 Critical Lands Workshop
Flathead Conservation District Presentation
River Integrity Presentation
Stillwater River Presentation
Y2Y Bird Priorities