Director's Notes
January/February 2010
The Great Cow Count
Cattle farming, just like many other land uses (residential and commercial development, forest harvest, crops, etc.) impacts stream conditions. But in the Rivanna basin, the importance of cattle farming relative to other land uses is not well understood. Looking at the watershed as a whole, are cattle a major stress? Or are cattle of negligible concern compared to development?
StreamWatch is trying to shed light on these and related questions by quantifying cattle populations and grazing acreage. Over the past few months, led by super-volunteer Gus Colom, StreamWatch volunteers have pored over high-resolution imagery of the Rivanna landscape, literally counting cows. We won’t find them all, but we will be able to quantify relative cattle farming intensity in Rivanna subwatersheds. For instance, we’ll be able to say that subwatershed “A” has higher cattle density per acre than subwatershed “B”. We can then compare these data to stream health in the subwatersheds.
The cow data will be analyzed along with other land use/land cover data in our Land Use Study. To our knowledge, analysis of this kind has never been performed in Virginia. We hope to shed new light on key land use/stream health questions, and to provide information that facilitates excellent stewardship by private and public landowners.
December 2009
Sampling for Bacteria
From May to November of 2008, StreamWatch collected fecal bacteria throughout the Rivanna basin. Carried out largely by University of Virginia students, the field work involved duplicate samples collected at each of 17 sites site once per month.
This effort was part of the Land Use Study we have been working on since 2007, and was intended to determine whether bacterial levels correlated meaningfully with the presence of cattle. Other studies and common sense suggest that bacterial levels should be higher in streams where cattle have direct access, and probably also where grazing occurs near streams. But can cattle-related bacteria be meaningfully measured by methods that are practical and affordable for StreamWatch?
Bacteria data could provide clues about the relative importance of cattle impacts. But we won’t know if the data collected in 2008 are useful until the Land Use Study analyses are complete and the report is published (May 2010).
November 2009
The Healthy Waters Project
StreamWatch is partnering with the Rivanna River Basin Commission and Virginia Commonwealth University (VCU) to collect data that will help identify biologically healthy subwatersheds. Many screening projects look for impairment with the idea of fixing sick streams. While this is necessary, the “Healthy Waters” approach is an exciting alternative that hopefully will help the community protect some of our best streams.
Another exciting aspect is the large amount of fish data that are being collected by VCU. There are not a great deal of data on Rivanna fish populations, so we might learn a lot!
StreamWatch is handling the bug data collection. You may have seen Rose around and about with the D-frame net used for this project. The field protocol is a bit different than our traditional kick-net method, but the basic idea is the same.
All in all, fish and bug data will be gathered at fifty-five sites in about 20 Rivanna basin subwatersheds. The size of each subwatershed, on average, is about one twentieth of the Rivanna basin, so this survey covers the entire Rivanna watershed (at least theoretically). Data collection will be finished by the end of the year, and Rivanna River Basin Commission will release the findings in mid-2010.
October 2009
Dear StreamWatch Community,
This fall we are beginning to analyze data collected over the past 2½ years for our Land Use Study. The study covers fifty sites on streams draining a diverse array of landscapes ranging from urban to suburban to rural to wild. The data include our traditional “bug” samples, and also sedimentation, stream geometry, and stream corridor habitat data. At the landscape scale we will use data about forest cover, impervious surfaces, agricultural uses, and more.
We expect that comparing stream conditions to land use and land cover in streams’ catchments will help us understand “how much” land disturbance streams can absorb before experiencing certain levels of degradation. We also expect the study will help private landowners and public stewards to evaluate the effectiveness and practicality of various management options. The report will be released in late spring of 2010.
This and other StreamWatch efforts are made possible by the steadfast contributions of volunteers. On behalf of Rivanna streams and rivers, please join me in extending a heartfelt thank you to these generous, forward-thinking citizens.
Sincerely,
John Murphy
Director, StreamWatch