
The Maryland Biological Stream Survey: A Foundation of Sound Science to Ensure the Future of Maryland's Streams
The Maryland Biological Stream Survey (MBSS) was started by the Maryland Department of Natural Resources in 1993 as a small pilot study in three watersheds. A second, larger demonstration project, expanded statewide, was conducted in 1994. The MBSS was Maryland's first probability-based or random design stream sampling program intended to provide unbiased estimates of stream conditions with known precision at various spatial scales ranging from large 6-digit river basins and medium-sized 8-digit watersheds to the entire state. The basis of the MBSS design is lattice or multi-stratification sampling that ensures all 1st through 3rd order (now 1st through 4th order), non-tidal streams in the sampling frame have a non-zero and known probability of being sampled. A stratified random design is a cost-effective way to characterize Maryland's 15,000+ miles of freshwater streams.
Current Status
The third round of statewide random sampling concluded in the summer of 2009. In 2011, MBSS sampled targeted areas around the state, as well as sites related to special circumstances, such as the influx of high flows due to heavy summer rains. In 2012, MBSS will conduct special project sampling and produce reports based on the data collected from 2007-2009.
Goal and Objectives
The Maryland Biological Stream Survey's goal is to provide the best possible information for ensuring the protection and restoration of Maryland's stream ecological resources.
Objectives to help meet this goal
- Assess the current condition of ecological resources in Maryland's streams and rivers
- Identify the impacts of acidic deposition, climate change, and other stressors on ecological resources in Maryland's streams and rivers
- Provide an inventory of biodiversity in Maryland's streams
- Assess the efficacy of stream restoration and conservation efforts to stream ecological resources
- Continue to build a long-term database and document changes over time in Maryland's stream ecological condition and biodiversity status
- Communicate results to the scientific community, the public, and policy makers
Products and Applications of MBSS Data
MBSS data is used for countless studies about freswater ecology. This section details some of the research that Maryland DNR conducts that focus on certain issues in the State. Some include:
- A Greater Understanding of Freshwater Fauna
- Assessment of Invasive Species
- Rivers and Streams Management
Reports and Publications
MBSS puts many of its reports, manuals, and fact sheets up on the web for public viewing. Included in this section are documents about the protocol used by MBSS. You can find all of these at the Publications page.
Maps of Watersheds Sampled in Each Round
Every round of MBSS sampling includes a statewide survey of the watersheds in Maryland. Our maps page has pictures of the watersheds sampled from round three, which took place during the years 2007-2009. This page also has maps detailing other projects and data.
MBSS Menu

- MBSS Home
- Training Information
- List of MBSS Certifications
- MBSS Round 3 Report
- What is the MBSS?
- Meet the Biologists
- When does MBSS Sample Streams?
- Products and Applications
- Online Publications
- Videos
- Statewide Fish Distribution
- MBSS Data Request
- The 2011 MD Stream Symposium and Mid-Atlantic Volunteer Monitoring Conference
Upcoming Events
- Save the Date! MBSS 2013 Summer Training - May 28-31
Learn More - Stream Waders Dropoff Day
May 4th - Ridgely, Rockville, and Grantsville locations
Learn More
Species Spotlight
- Long-tailed Salamander
The Long-tailed Salamander (Eurycea longicauda longicauda) This salamander is found everywhere in Maryland except the Coastal Plain. It lives up to its name with a tail that makes up more that 50% of its total length.
Learn more in this informative Fact Sheet

