Stream health is heavily impacted by nearby land use practices, the quality of the riparian corridor, and land cover within the watershed. Forest cover is particularly effective at protecting stream health, as forests stabilize soil, filter stormwater, and prevent pollutants from reaching our waterways. Recent land cover data in Albemarle County shows approximately 72% forest, 24% open land, and 3% classified as impervious, or developed.  

_{Photo: Chesapeake Bay Program}

Monitoring changes in land cover over time can provide a good indication of the impacts of land use on stream health. Recent changes in land cover data show a net loss of forest in the county, which is a consistent trend statewide in Virginia. The Rivanna Conservation Alliance (formerly Streamwatch) conducted a study on the relationship between land use and stream health in the Rivanna Basin, which covers much of the county. The study found that rural landscapes that are predominantly forested have the healthiest streams, and that stream health declines as land use intensifies. In particular, the study found that above a certain threshold of impervious cover within a watershed, the biological condition of its streams starts to decline. The study also projected that within 20 years, increased development, decreased forest cover, and population growth could reduce the number of healthy streams by 1/3.  

Land conservation is one tool that helps protect rural land uses and riparian buffers in perpetuity. In 2021, over 127,000 acres (27%) of Albemarle County is permanently protected in conservation, either as public parkland or private conservation easements. 

This map shows the percent of unbuffered streams within each subwatershed in the county, ranging from <5% to 25%. Land classified as ‘unbuffered’ includes any area within 35’ of a stream without woody or wetland vegetation. Many areas of the county are well-buffered overall, likely due to the high percentage of forested land and the success of cost-share programs that support buffer planting and retention. However, there are also areas that indicate there is potential for significant improvement. 

There are few creatures in Albemarle County that do not depend on stream corridors for some basic need.  We typically think of streams as being the home of fish, turtles, frogs, and other aquatic wildlife that spend their whole lives in or next to waterways.  But there are many animals and insects that move in and out of stream buffers on a daily, seasonal, or life cycle basis.  They may come seeking water to drink, food to eat, shelter from the weather, or safety from predators.  They may also come to bathe or cool off during hot spells.  Intact and connected acres of streamside forest and other natural landscapes are necessary to provide safe passage for animals that need to move between and along waterways.  Connectivity within stream and river channels is also very important for the life cycle of many species of fish and amphibians.  Often, road culverts and dams can make upstream reaches inaccessible to certain species of fish and amphibians, essentially eliminating those sections of stream as potential habitat for them. 

_{Photo: Chesapeake Bay Program}

Albemarle County is home to a broad range of types and sizes of waterways – from steep, narrow, and cool headwater streams in the west against the Blue Ridge Mountains, to wide and slow-moving Piedmont streams in the central and eastern parts of the county.  Several unique and prized aquatic organisms are present in these different types of streams.  Brook trout can be found in those cooler fast-flowing mountain streams, while rare freshwater mussels have been found in the shallows of some of the county’s cobble-covered and winding streams.

_{Photo: David Hannah}

To measure how hospitable a stream is for wildlife in general, some scientists take a careful look at what are called “benthic macroinvertebrates” – small animals that live in the rocks, leaves, and sticks at the bottom of streams. Some species of these macroinvertebrates are very intolerant of pollution and disturbance, while others can survive in practically any conditions. By monitoring the abundance and variety of macroinvertebrate species living in waterways, the Rivanna Conservation Alliance (RCA) has been able to assign a “score” to many of the streams in Albemarle County since the program started in 2003. RCA’s biological monitoring results for years 2018-2020 show that 8% of the streams monitored within the Rivanna watershed were “very good”, 10% were “good”, 70% were “fair”, and 12% were poor. Learn more about RCA’s analysis of long-term benthic trends in the Rivanna Watershed. 

Read the latest RCA Stream Health Report 

Naturally, water levels in streams constantly fluctuate – less flow in times of little precipitation, and higher flows after recent rainfall.  The U.S. Geological Survey (USGS) maintains several gauges that monitor water levels in Albemarle County streams and rivers.  Current and past stream flow condition data collected by those gauges can be found on their WaterWatch website.   

_{Image: David Hannah}

The extent to which water levels go up and down in Albemarle County’s streams, can have big consequences for not only plants and animals living there, but also for land and infrastructure.  Intense rainfall and flooding are especially detrimental to stream systems as rushing water picks up large amounts of clay and silt (sediment) from the landscape and deposits it in the stream bottom where it smothers habitat.   

This kind of flooding also washes away sediment and vegetation from streambanks, undermining roots of riparian trees and leaving them more vulnerable to falling over in subsequent floods.  In general, streams in Albemarle County where riparian vegetation is more intact and within more forested watersheds experience less extreme fluctuation in water levels.  Absorbing rainfall in the landscape and keeping riparian forest healthy is our best defense against flood damage.