Water Quality Monitoring Programs in Fairfax County, April 2014
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Transcript of Water Quality Monitoring Programs in Fairfax County, April 2014
Water Quality Monitoring Programs in Fairfax County
POTOMAC WATERSHED ROUNDTABLEAPRIL 4, 2014
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Monitoring Milestones1969 - Health Department stream monitoring1984 - Gunston Cove ecological study 1986 - Kingstowne environmental monitoring program1998 - Stream Protection Strategy 2002 - Perennial streams mapping project2002 - Stream Physical Assessment2003 - Watershed management plan development 2007 - UGSG gages partnership/study
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Early Surface Water Monitoring
…any open, unprotected body of water is subject to pollution from indiscriminate dumping of litter and waste products, sewer line breaks and contamination from runoff pesticides, herbicides, and waste from domestic and wildlife animals. Therefore, the use of streams for contact recreational purposes, such as swimming, wading, etc., which could cause ingestion of stream water or possible contamination of an open wound by stream water, should be avoided.
Fairfax County Health Department Annual Stream Water Quality Report• Initiated in 1969• Bacteria (fecal coliforms),
temperature, pH, nitrogen, phosphorus, dissolved O2 and heavy metals
• 85 sites – sampled 2x monthly• Ceased in 2003 – program assumed
by Stormwater Planning (DPWES)• Annual statement:
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Early Surface Water Quality MonitoringGunston Cove Ecological Study Ongoing 30-year study (est. 1984) Partnership with GMU Observe effects of wastewater
treatment plant (WWTP) on estuary
Very poor ecology 1970s-80s (eutrophication)
Evaluate WQ parameters Phyto-, zoo- and ichthyoplankton Adult and juvenile fish Submerged aquatic vegetation Bentic macroinvertebrates
Internationally recognized case of ecosystem recovery
TIME LAGS (10 to 15 years)
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Early Surface Water Quality MonitoringKingstowne Environmental Monitoring Program23-year study (1986-2012)Large scale development project
upstream (1.8 mi2) Huntley Meadows Park wetlands
downstream (1,500 ac)Potential siltation of wetlands Measure storm and baseflowsEvaluate watershed-wide BMP
efficienciesAverage total suspended solids (TSS) efficiency greater than 80%Trend analysis: downtrend in TSS
(1986-2001)
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Stream Biological Monitoring Program Fairfax County Stream Protection Strategy (SPS) Established by BOS in 1998 to assess
WQ/stream/watershed conditions Countywide
Evaluated chemical, biological, habitat and geomorphic conditions at 124 sites in 1999
2001 SPS Baseline Study >70% of streams in fair to very poor
condition (impaired) Urbanization, imperviousness and STW
implicated as primary stressors Established management categories (3) Recommendations included: SPA, develop
WMPs, long-term monitoring program, explore STW Utility. All implemented!!
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Stream Biological Monitoring Program
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Stratified-random evaluation framework (2004) Similar to VA’s probabilistic monitoring
program Sites stratified by stream order (1st – 5th) Statistically valid way to make inferences
on countywide stream condition40 sites selected annually. Sampled for:
Benthic Macroinvertebrates (spring) Fish and habitat (summer) Bacteria (quarterly) Water quality (every visit) 12 reference sites
Annual Stream Quality Index (SQI) [score 1-5]
Stream Biological Monitoring Program
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Dry Weather ScreeningScreening program for illicit discharges or improper connections to storm drainage network 100 - 120 outfalls screened annually Suite of chemical and physical parameters
tested Parameter exceedance triggers recheck
and/or trackdown of upstream source(s) Investigations fully documented Highly effective at detecting and eliminating
pollutants from surface waters
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Wet Weather ScreeningStorm event monitoring programHigh-intensity land use areasTarget areas with high pollution
potentialPrioritized site selection protocol Two sites monitored each year
Sampled quarterly (8 events)Stormwater tested for full suite
of conventional runoff pollutantsExceedences may trigger
trackdowns or referral to Industrial and High Risk Runoff (IHRR) inspection program
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Watershed MonitoringOngoing since 2003Paired watershed studyStorm runoff sampledEvaluate trends in WQCharacterize runoff
from different land uses
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Special Studies2002-2004 USGS Partnership: Accotink Creek Bacteria (TMDL) Source Tracking Study
Large suite of biological and chemical tracers used
more than 100 sites sampled (in one day) every quarter
“Hot spots” identified Bacteria ubiquitous throughout
densely-populated upper watershed
Improved sampling techniques
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Innovative Stormwater BMP MonitoringMonitored 2008-20123 sites - county stormwater retrofits 2 rain gardens, 2 green roofsData analysis by VA Tech Occoquan
Watershed Monitoring Laboratory (OWML)
Excellent pollutant and volume reductions on smaller storms (greater than 2”)
Innovative Stormwater BMP Monitoring
Cinnamon Oaks dry pond retrofitMonitored 2010 to presentPartnership with VA Tech
OWMLCalculate pollutant loads (in vs.
out)Calculate removal efficienciesImprove future retrofit designs,
construction and maintenance
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Lake Studies Lakes Huntsman and Barton Highly eutrophic (nutrient rich) Dredging schedule Characterize lake… Water quality issues (no O2 greater
than 4’ deep) Employ circulation Continue monitoring Post-dredge lake restoration Goal: maximize ability of these
lakes to provide water quality improvements to downstream waters
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USGS Partnership: Stream Gaging Study Initiated in 2007 in conjunction with the USGS VA Water
Science Center (Richmond)Billion$ being spent nationwide on Stormwater BMPs
How well is our current technology working? Many studies on site-specific BMP performance, but... …what about watershed-level responses?
Paramount study at small watershed scale to quantify sediment and nutrient yields and effects of BMP implementation
Benefits from study/data?
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Stream Gage Study with USGSObjectives:1. Generate long-term monitoring data to
describe: Current water-quality conditions Trends in water-quality, nutrient and
sediment loads and yields2. Evaluate relations between observed
conditions/trends and BMP implementation.3. Transfer the understanding gained to other
less-intensively monitored watersheds.
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Gage Study: Objective #1
Operate 4 intensive monitoring stations
10+ years of data collection Continuous-record stream gage Continuous water-quality monitor
Turbidity, pH, SC, temp, DO Nutrients and Sediment
Sampling Automated sampler (storm samples) Scheduled monthly sampling
Annual benthic macroinvertebrate monitoring
1. Generate long-term monitoring data to describe: Current water-quality conditions Trends in water-quality, nutrient and sediment
loads and yields
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Gage Study: Objective #22. Evaluate relations between observed
conditions/trends and BMP implementation
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Gage Study: Objective #3
Operate 10 less-intensive monitoring stations
Partial-record stream gage Nutrient and sediment sampling
Scheduled monthly sampling Annual benthic macroinvertebrate
monitoring Evaluate relations between trend -
and intensive monitoring sites Saves $$$ while expanding
dataset and predictive capabilities
3. Transfer the understanding gained to other less-intensively monitored watersheds
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Gage Study: Monitoring Network• Site selection optimized
using statistical analyses of large dataset:• land use• impervious cover• physical stream condition• biological scores • planned BMP
implementation• 14 sites:
• 4 fully-gaged sites (continuous data collection)
• 10 partial-record sites (scheduled data collection)
• All watersheds greater than 5 mi2
• Expanded in 2011 (6 sites added)• 1 fully-gaged site• 5 partial-record sites
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Gage Study: Data Analyses and BenefitsRich dataset allows for enormous amount of
robust analysesCharacterize baseline conditions after 5 yearsTrend analysis after 10+ yearsUltimately show effect of BMPs on watershedsUnanticipated learning (Triassic basin P)Data inform restoration designsPublication imminent (1st five yrs. data)Several “piggyback” studies describing:
Floodplain dynamicsSediment transport Stream metabolism
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Gage Study: Data Analyses & BenefitsCompare to other systems
Atlanta urban streamsNorth Carolina studyOccoquan watershedUSGS bay-wide network
Chesapeake Bay Model “Reality Check”Compare monitored data to
modeled dataPotentially use to calibrateEvaluate load allocationsUnique dataset (smaller
watersheds)
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Gage Study: Data AccessAll data published on WWW for viewing and downloadingNear-real time (updated hourly)
Stream flow (5 min. intervals)Stream discharge (5 min. intervals)WQ parameters (15 min. intervals)
As received (from laboratories)Sediment (TSS)Nutrients (N and P species)
Available for viewing and downloading in both tabular and graphical formats
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So… what do we know??Monitoring is necessary, but not cheap.Stream conditions have changed little …so far.
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So… what do we know??Time lags are REAL – results don’t manifest
overnight.Cleaning up Stormwater runoff is technically
challenging and expensive – but we’re definitely getting better!
Floodplains, wetlands and other preserved natural areas are providing beneficial functions
Urban streams may never recover full functionality…Likely need to target for “best attainable conditions”
No “silver bullet” cure. Will require multi-faceted approach
Government(s) can not do it alone
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Thank you.Shannon Curtis, Ecologist IVStormwater Planning DivisionDepartment of Public Works and
Environmental ServicesFairfax County703-324-5500, TTY 711www.fairfaxcounty.gov/dpwes/stormwaterA Fairfax County Publication, April 2014