Water quality permits in California for projects impacting wetlands, “blue-line” streams, and other jurisdictional water bodies are starting to require sampling for “water bugs” known as benthic macroinvertebrates (BMI).
BMI live on or in the substrate under bodies of water. They respond quickly to changes in water quality and nutrient input and are regarded as an appropriate measure of the biological suitability of water bodies.
California’s Regional Water Quality Control Boards (RWQCBs) are adding BMI sampling requirements to new Section 401 water quality certifications and Section 402 point-source discharge permits. It is anticipated that BMI sampling may also be more widely incorporated into NDPES permit conditions for water/wastewater agencies in California within the next two years, as has occurred in Florida, Minnesota, Washington and Nebraska.
BMI sampling requirements in California often specify the use of the Surface Water Ambient Monitoring Program (SWAMP) protocol for quantifying, identifying and determining the health of BMI communities. The California Department of Fish and Game (CDFG) developed the protocol, and intends for data to be used as a universal indicator of a water body’s overall environmental and biological health. This specific protocol is designed for wade-able perennial streams. However, CDFG is currently developing water quality sampling protocols applicable to various other aquatic resource types.
Experience and careful planning is required to ensure successful implementation of BMI sampling based on a project site’s spatial constraints, available stream flow, land access and project schedule.
Christopher Oesch, a Dudek senior habitat restoration biologist, offers the following considerations for implementing the new BMI sampling requirements:
- Field sampling can be done only in the spring and summer during the regional sampling “Indexing Period,” and must be done by personnel certified for the protocol by CDFG. For projects in Southern California where streams often do not flow in the summer, the applicant must negotiate the terms of specific BMI permit criteria to reflect the feasibility of water quality sampling.
- Given the regionally overlapping Indexing Periods throughout California, completion of lab analysis can take 6 months or longer depending on the volume of samples submitted and the backlog at the lab.
- Evaluating and documenting any pre-existing toxic conditions at a project site is vital to ensure the permit does not assign responsibility to the applicant for mitigating existing conditions not related to their project.
“CDFG is currently establishing regional baselines for healthy stream communities throughout the state,” Oesch said. “The Northern Sierras and North Coast have a large sample size of reference streams to establish baseline conditions and thresholds. The Central Valley and Southern California, however, have very few ‘healthy streams,’ due to agriculture, urban development and drier climate. This drastically smaller sample size should result in the adoption of less comprehensive sampling standards for these regions. However, if Southern California applicants do not carefully document any adverse pre-existing conditions for each site, and the regional standards are relied upon, the applicant will likely be held by their permit to criteria not reflective of those adverse, pre-existing conditions.”
Oesch offered the following planning suggestions:
- For project scheduling, attempt to get permits issued in the winter or spring to utilize the soonest upcoming Index Period.
- While negotiating permit conditions, assess the project site for technical issues (e.g., no stream flow in summer for sampling, spatial constraints, etc.) that render sampling infeasible, and develop a permit negotiation strategy.
- Bundle all the water-quality and sampling-related environmental work for efficiency. The SWAMP protocol is usually in addition to other water quality monitoring work required in the permit.
- Expect additional time and cost related to the BMI sampling requirements. Field sampling and laboratory sample processing/analysis are extremely detailed and lengthy.