Nevada began its Bioassessment Program in the year 2000 and has continued to collect biological, chemical and physical habitat information on an annual basis throughout Nevada. The program's goal consists of developing biological tools that can be used to evaluate the ecological condition and identify stressors in Nevada streams, rivers and lakes. The goal is being accomplished by conducting biological, chemical, and physical habitat surveys throughout the state that include both a targeted survey design and a probabilistic approach.
Field Survey Protocols, Laboratory Identification and Analysis
The targeted survey design is being implemented with the key objectives: to identify reference sites or those waterbodies least impacted from anthropogenic sources, to evaluate and assess current conditions at a particular site, and to establish a baseline for trend analysis. In contrast, the probabilistic survey design provides an unbiased approach that can be used to develop percentages to evaluate the state's overall ecological conditions and identify the relative importance of water-body stressors within the state.
The identical field sampling protocols are implemented in both the targeted and probabilistic monitoring approach. The field methods consist of protocols developed by U.S. EPA's National Rivers and Streams Assessment Field Operation Manual (EPA-841-B07-009) or U.S. EPA's National Lakes Assessment. Field measurements or samples collected at a monitoring site can include any of the following parameters depending on the monitoring design criteria:
- Water Chemistry* (nutrients, pH, dissolved oxygen, temperature, and conductivity)
- Water Metals* (dissolved and total recoverable)
- Physical Habitat - channel dimensions, stream gradient, thalweg profiles, bank slope, water depth, pebble counts, and canopy cover
- Riparian and Stream Condition Evaluations - human influence, invasive species, fish cover, algae and aquatic macrophytes, woody debris and bank vegetation type and cover
- Stream Discharge
- Survey Design Dependent Parameters Include:
1) Fish Counts, 2) Identification and Contaminates Levels*, 3)Sediment Metals*, 4) Plankton Identifications*, 5) Secchi Depth, and 6) Chlorophyll and Biomass*
*Requires Independent Laboratory Analysis or Identification
Data is compiled and reviewed in Nevada's Ecological Data Application System (NV-EDAS). Survey results and laboratory analysis or identifications are available to other agencies and the public upon request. Contact:
Additional Information and Reports
Provided below are various bioassessment reports that contain information developed at the State and National level.
Biological Condition Index Development for the Lower Truckee
River and Eastern Sierra Nevada Rivers: Fish Assemblage
Biological Condition Index Development for
the Truckee River: Periphyton Assemblage
Carbon and Nitrogen Stable Isotopes on the Truckee River: Results of March 2004 Sampling
Benthic Macroinvertebrates Index Development and Physical Habitat Evaluation for Truckee River, Carson River, and Walker River
Appendix A - Benthic Macroinvertebrate Data – Metric Values
U.S. EPA Wadeable Streams Assessment: A Collaborative Survey of the Nation's Streams
U.S. EPA National Lakes Assessment Report