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