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Understanding the Effectiveness of BMPs: Synthesizing Lessons Learned from Water Quality Monitoring Studies. Katie Foreman & Liza Hernandez August 15, 2012 Joint TMAW/NTWG meeting. Outline. Background on the project Products and timeline Summary of lessons learned
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Katie Foreman & Liza Hernandez
August 15, 2012
Joint TMAW/NTWG meeting
Synthesizing the state of knowledge from monitoring studies that look at the effectiveness of BMPs
Lesson:At the scale of the Chesapeake Bay watershed, the most obvious and quickest improvements in water quality have been from wastewater treatment facility upgrades
Recommendation: Continuing the funding of wastewater treatment plant upgrades is critical to reduce loads and offset population growth
Evidence: 3 CB stories, 4 national stories, long-term NT trends
Potomac River, MD (Blue Plains WWTP): TN load decreased 56% after implementation of BNR
Back River, MD: since 1980s upgrades to the WWTP (Back River WWTP, which servicing parts of the Baltimore metro area) have reduced P (7-fold reduction) & N loads (2x reduction)
Lesson: Nutrient management that focuses on reducing the initial input of nutrients into the system is one of the best ways to reduce nutrient transport off the landscape
Recommendation: Reduced fertilizer use (from residential and agricultural sources) and reduced solids (biosolids and animal manure) through effective nutrient management plans and innovative technologies is necessary
Evidence: 5 CBW stories (many stream fencing stories), 3 itn’l/national stories
Upper Potomac River, MD: 100% removal of chicken litter lead to reduction in nutrient surpluses and reduction in TN concentrations by 30%
Big Spring Run: Stream bank fencing lead to sign. improvements in benthic communities, habitat, and decrease in N, TP, and SS yields
Lesson:Relatively large amounts of implementation are required to observe significant water quality and habitat responses
Recommendation: Develop an accounting of nutrient sources to target types and amount of effort needed to achieve desirable outcomes
Evidence: 18 CB and CBW stories, 9 itn’l/national stories
Brush Run Creek, PA: BMPs that provided a 57% reduction in P and SS lead to a significant decrease in concentration and loads, but no change in N because only a 14% reduction in source
Corsica River, MD: Not enough BMPs, the TN reduction is only 30% of the TN load -- Boynton et al. (2009) concluded that at least a 50% reduction in the TN loading to the estuary is necessary to reach goals
Lesson:The majority of nonpoint source BMPs will take years to decades to improve water quality in the watershed; once water quality improvements reach the estuary, the response can be rapid (years)
Recommendation: There is no better time than now to accelerate nonpoint source BMPs followed by persistence and patience to detect measureable improvements in water quality
Evidence: 9 CB and CBW stories, 7 itn’l/national stories
German Branch Choptank River, MD: The time lag associated with the long residence time for nutrients in groundwater suggests that there will be a multi-year to decadal delay in signal detection of implementation/water quality relationships.
Back River, MD: Particulate N & P stored in the sediments lead to a "system nutrient memory". This nutrient memory results in a lag between management actions and ecosystem responses.
Lesson: Untargeted BMP implementation spread across broad regions have not produced measureable desired results
Recommendation: BMPs must be focused (both type and location) and significant in magnitude to address the main sources of water quality impairment
Evidence: 9 CB and CBW stories, 13 itn’l/national stories
Buffer studies, CBW-wide: Buffer effectiveness depends on placement downhill from nutrient sources, inherent removal potential (varies spatially and temporally) particularly by bioregion (95% vs. 35%, C. Plain vs. Piedmont)
Choptank River, MD: Trends in water quality indicate that current efforts to improve water quality are failing to prevent further degradation; further reductions in nutrient inputs particularly targeting NPS are necessary
Lesson: Improvements in water quality as a result of BMPs may be offset by increasing nutrients in other sources
Recommendation: Restoration goals and expectations should be set with knowing the offsets are a reality and that desired outcomes from some BMPs might be eclipsed by increases in other sources
Evidence: 6 CB and CBW stories, 5 itn’l/national stories
Bald Eagle Creek, PA: Even with large reductions in nutrient inputs, there were many factors changing at one time including a reduction in corn cropping and increase in legume cropping which coincided with an increase in base flow concentration of nitrogen and dissolved nitrite+nitrate
Patuxent River, MD: High levels of implementation (particularly NPS) need to be continued; reducing N and P inputs will be required to help offset the effects that would otherwise be experienced with population increases.
Lesson:Apart from point source tracking, information is limited at the sub-county scale to track BMP implementation
Recommendation: Improvements are needed for local tracking of voluntary and cost-share BMPs to enhance models for targeting of BMP implementation
Evidence: 4 CB and CBW stories
Little Conestoga Creek, PA: Lack of information on the changes in nutrient applications from year to year and the degree of implementation of BMPs from farm to farm have affected the ability to determine effectiveness
German Branch Choptank River, MD: It was impossible to verify the full extent of BMP implementation, both in space and time. It was not clear where or that all BMPs were implemented simultaneously, therefore complicating signal detection.
Lesson: Only 5% of BMP projects watershed-wide were monitored for their effectiveness and not at necessary scale to access effectiveness
Recommendation: Improvements are needed to enhance monitoring of BMPs as well as water quality and habitat responses
Evidence: 7 CB and CBW stories, 5 national stories
Anne Arundel County Streams, MD: There is a lack of pre-restoration data to evaluate response of streambank stabilization projects
German Branch Choptank River, MD: The scale of the project was too large to link specific BMPs to potential improvements in WQ
Lesson: Most BMP implementation is not designed using lessons learned from rigorous evaluation results, rather on assumptions of the modeled efficiencies of BMPs
Recommendation: Evaluating the effectiveness of water quality and habitat monitoring programs and BMP projects will require a better understanding of the lessons learned from past BMP projects and the application of those lessons learned through adaptive management
Evidence: 4 CB and CBW stories, 1 national story
Minebank Run, MD: Restored streams in urban watershed may have different capability of transforming nitrogen at the riparian-zone-stream interface than streams in undeveloped watersheds that have been much more thoroughly studied
CBW-wide study (Weammert): More research on conservation effects at field and watershed scales is needed as there is much spatial and management variability. More information is essential so that uncertainty in estimates of conservation effects can be reduced in model “efficiencies”.