1、Water QualityIntro by Erick BjorklandChesapeake Bay Case StudyBrandon PowersCreated Wetlands by Carol Ann DulinSaltwater Case Study byMeghan BarronClean Water ActIn 1972 congress adopted the Clean Water Act, to restore and maintain the chemical, physical and biological integrity of the nations water

2、s.Water Quality Allows States,Tribes and Jurisdictions to set their own water quality standards, but requires that they met and include the “fishable and swimmable” goals of the act.Water QualityProvides for the protection and propagation of fish, shellfish and wildlife.It provides for recreation in

3、 and on the water.These are the “fishable and swimmable” goals of the Clean Water Act.Water Quality Water quality has three elements.Designed usesCriteria developed to protect each useAntidegradation policyDesignated UsesWater Quality CriteriaNumerical establish thresholds for the physical, chemical

4、 and biological attributes required to support a beneficial use.Narrative describe, rather than quantify, conditions that must be maintained to support a designated use.Antidegradation policiesNarrative statements intended to protect existing uses and prevent waterbodies from deteriorating even if t

5、heir water quality is better than the fishable and swimmable goals of the Act.Summary of Use Support for U.S. WatersStates reported that 49% of their assessed estuarine waters have good water quality that fully supports designated uses.The remaining 51% has some form of pollution or habitat degradat

6、ion.States Reported That Pollutants:Impact aquatic life in 11,391 square miles (about 52%) of estuarine waters.Restrict fish consumption in 6,255 square miles ( about 48%) of estuarine waters.Restrict shellfish harvesting in 5,288 square miles ( about 25%) of estuarine waters.Violate swimming criter

7、ia in 3,245 square miles ( about 15%) of estuarine waters.PollutantsPollutants come from point and nonpoint sources (NPS).NPS include stormwater, diffuse agricultural runoff from pastures and row-crops, concentrated agricultural wastes from feedlots, runoff from building sites, forestry activities,

8、drainage from mining activities.NPS contribute 65% of the total pollution load to U.S. inland surface waters (Olson).PollutantsMost often there is more than one pollutant impacting a single estuarine waterbody.There are more square miles of estuarine waters polluted by metals than any other pollutan

9、t or stressor. Mercury is the primary metal pollutant.The largest number of impaired streams and rivers is in the Appalachian region. This is caused by the leaching of heavy metals.Pollutants in EstuariesPesticides pollute 5,985 square miles.Oxygen depletion from organic wastes impact 5,324 square m

10、iles.Pathogens impair4,764 square miles.Pesticide pollution The greatest potential for pesticide contamination is on the eastern seaboard.Runoff is the major mode of transportation but 10-30% come from aerosol drift.Still getting DDT from S. America via this mode.Pesticides are even being detected i

11、n groundwater (atrazine, aldicarb and alachor)Nitrogen and PhosphorousLarge amounts of N and P can cause to much vegetation growth and decay, leading to water chemistry changes and limited vegetation diversity. Depending on the wetland, one or the other can act as a limiting agent for algal growth.S

12、tate Reported SourcesMunicipal point sources (sewage treatment plants) are the most wide spread polluters (5,779 square miles).Urban runoff impacts 5,045 square miles.Industrial discharge pollute 4,116 square miles.Atmospheric deposition impacts 3,692 square miles.Polluters and SourcesBenefits and D

13、rawbacksThe Congaree Bottomland Hardwood Swamp removes the amount of pollutants annually that a 5 million $ treatment plant would.Approximately 43% of the federally threatened and endangered species rely on these wetland.400 treatment plants discharge to natural wetlands in the Southeast alone.Some

14、wetlands receive all or most water inputs from sewage discharge.State of the NationOnly 8% of the Nations total wetlands are surveyed.Water Quality in the Chesapeake BayChesapeake BayLargest estuary in North AmericaDrains portions of six statesVirginiaMarylandDelaware PennsylvaniaNew YorkWest Virgin

15、iaThe District of ColumbiaChesapeake Bay WatershedTop 4 Stressers on the Bays SystemsToxic ChemicalsAir Pollution Excess NutrientsHuman InfluenceMain Cause of Chesapeake Bays Poor Water QualityExcess NutrientsCase StudyBenefits of water quality regulation in the Chesapeake Bay region from 1972-Prese

16、ntFindings based on model changes in ambient water qualityFocuses on Nitrogen (N) and Phosphorus (P)Effects of Excess NutrientsElevated levels of Nitrogen (N) and Phosphorus (P) create algal bloomsDepletes Oxygen (O)Blocks SunlightLinked to outbreaks of pfiesteria (a toxin causing lesions on fish)Mo

17、re Effects from Excess NutrientsFish KillsWater unfit for recreational activities(boating, fishing, swimming)Harmful to shellfish rendering them unfit for human consumptionCan cause human respiratory problems form toxins released into the air Chesapeake Bay ProgramSpurred by the Clean Water Act (CWA

18、) The First Chesapeake Bay Agreement was signed in 1983MarylandVirginiaPennsylavaniaDistrict of ColumbiaChesapeake Bay Commission ( a tri-state legislative body)U. S. Environmental Protection AgencyChesapeake Bay Agreement 1983Set up Chesapeake Bay CouncilImplemented Water Quality Monitoring Program

19、Directly measured 19 water quality parameters49 stations in tributaries and mainstem bay2 times a monthChesapeake Bay Agreement 1987Set a goal to reduce the nutrients Nitrogen (N) and Phosphorus (P) entering the Bay by 40% by the year 2000Chesapeake Bay Agreement 1987Identified main sources of nutri

20、entsFarmlandUrban LandscapeWastewater Treatment PlantsIntroduced Nutrient Reduction PracticesNutrient Reduction PracticesNutrient and animal waste management on agriculture landConservation tillageVegetated buffer strips at the edge of fieldsStream bank fencingDitching Nutrient Management PlanningNu

21、trient Reduction PracticesPhosphate Detergent BansWastewater Treatment PlantsUrban Best Management PracticesErosion and Sediment ControlsStormwater ManagementSeptic System ManagementNutrient Reduction PracticesPoint Source ControlsWastewater Treatment Plant UpgradesBiological Nutrient Removal (BNR)I

22、n 1992 the Chesapeake Bay Program Partners agreed to continue the 40% reduction goal beyond 2000 and began to attack nutrients at their sourceUpstream and the Bays tributariesUse long-term monitoringComputer modeling Chesapeake Bay Agreement 2000Bay Program Partners agree to work with the headwater

23、statesDelawareNew YorkWest VirginiaChesapeake Bay Agreement 2000Continue to improve on previous Nitrogen (N) and Phosphorus (P) goalsImplemented new water quality standardsUse Total Maximum Daily Load (TMDL)ResultsBetween 1985 and 1997Annual Phosphorus (P) loads reduced by 8 million lbsAnnual Nitrog

24、en (N) loads reduced by 32 million lbsResultsPoint Source Reduction between 1985 and 1997Annual Phosphorus (P) loads reduced by 16 million lbsAnnual Nitrogen (N) loads reduced by 5 million lbsResultsNon-Point Source Reduction between 1985 and 1997Annual Phosphorus (P) loads reduced by 16 million lbs

25、Annual Nitrogen (N) loads reduced by 1 million lbsEstimated BenefitsTotal Benefits includeRecreation (fishing, boating, swimming)Commercial (fishing)HealthNon-use valuesProperty valuesRegional economic valuesEstimated BenefitsPeople in the Chesapeake Bay Watershed have received benefits that range f

26、rom $360 million to $1.8 billion in total benefitsBeach users benefits range from $290 million to $1.5 billionTrailered boating benefits range from $7 million to $84 millionWhy wetlands for wastewater treatments?Water saturated conditions lead to reduced gas exchangeLess gas exchange contributes to

27、higher anaerobic activity, allowing abundant microbial growthCombined, these attributes allow wetlands to transform organic materials into nutrients.Improving Water QualitySettling of particulate matterFiltration and chemical precipitation through contact of water with substrateBreakdown and transfo

28、rm pollutants by microorganisms Wetland SystemsFree Water Surface SystemsBasins or channelsNatural or constructed barrier to prevent seepageShallow water depth, low flow viscosity, and presence of the plant stalks to regulate water flowSubsurface Flow SystemsTrench or bed with impermeable layerBuilt

29、 with slight inclination between inlet and outletWaste water flows horizontally through rhizosphere of wetland plantsWastewater then treated by filtration, sorption, and precipitation processes in the soil and by microbial degradationThe effluent is then collected at the outlet channel and discharge

30、d Things to keep in mind when designing a wetland for waste water treatmentHydrology- most important!Climate and weatherHigh flows by rain and increased snow melt shorten the residence time of pollutants and efficiency of treatment decreasesHeavy rain after period of dryness has greatest impact on t

31、reatment efficiencyFreezing temps can reduce efficiency SubstratesSoilsIdeal soil pH for treating wastewater: 6.5- 8.5Electrical conductivityAffects the ability of plants and microbes to process the waste material. Should be less than 4 for water treatmentSoil - Water controlSoils capacity to retain

32、 and remove containmentsSandy or gravely soils have high porosity valuesHigh clay content helps retain phosphorusVascular PlantsStabilize substrates and limit channelized flowSlow water velocities, allowing suspended materials to settleTake up Carbon, nutrients and trace elements and incorporate the

33、m into plant tissuesTransfer gases between atmosphere and sedimentsMost wetlands are commonly constructed with emergent vegetation such as bulrushes, cattails and reedsAcid Mine TreatmentTreat acid from mine spoils and refuse, as well as coal ash disposal areasCreated by limestone, 2ft soil (clay),

34、plastic and fabric covered limestone backfill. Plant vegetationSerica, or crown vetchDiscourage establishment of trees which penetrate limestone drainsPulp Mill TreatmentMarshes can be used as a tertiary treatment of bleach kraft pulp mill effluentLignin burned for energy is mostly recovered, but so

35、me is lost in wastewater leading to high biochemical oxygen demandFree water surface wetland cells planted with torpedo grass, cattails, reeds, cord grassReduces water quality containmentsLandfill LeachateLandfill leachate is high in BOD, ammonium, iron and manganese. If not treated properly, surfac

36、e and ground water contamination is highly probable.Wetlands can aid in the tertiary treatment of leachate to reduce the likely hood of water contamination.Leachate is piped from landfill, to wetland where the minerals and BOD are reduced.New Hanover County Landfill2 cells with surface flow wetlands

37、Water flows above river rock bedding2 cells with subsurface flowLeachate flows below top of river rock beddingPlant Species involved:Softstem bulrushPickerel weedArrow headSoft rushSweetflagArrow arumLizards tailBurreadProved that wetlands may serve as a tertiary treatment system providing final fil

38、tration or polishing of treated leachateAdvantages of Created WetlandsLess expensive to build than treatment plantsOperation and maintenance expense is lowPeriodic onsite laborTolerate fluctuations and flowFacilitate water reuse and recyclingProvide habitat for wetland organismsEnvironmentally sensi

39、tiveLimitations of Created WetlandsPerformance may be less consistent than in conventional treatmentMay vary seasonallyFlushes of pollutants or surges in water flow may temporarily reduce effectivenessRequire a minimum amount of waterCase StudyGeneration of Enterococci Bacteria in a Coastal Saltwate

40、r Marsh and Its Impact on Surf Zone Water QualityS. B. Grant et al.Enterococci bacteria - An indicator of fecal pollution- Responsible for 97% of beach advisoriesPlagues the surf zone at Huntington State and City Beaches in Southern California during summers of 1999 & 2000Causing beach closures and

41、serious economic lossState law mandates water quality testing to protect beach goers High concentrations of bacteria are found in urban runoff, bird feces, marsh sediments, and on marine vegetationThe StudyStudy designed to characterize the sources and transport of ENT bacteria in saltwater marsh an

42、d tidally influenced flood control channels.Runoff from the Talbert Watershed is conveyed along street gutters to inlets that connect to underground stormwater pipelines. Pipelines connect to flood control channels that converge at a restored wetland, Talbert Marsh.Talbert Marsh is a 10 hectare remn

43、ant of what used to be and 1200 hectare saltwater wetand and dune system in coastal Orange CountyRestored in 1990 Typical CA tidal saltwater marsh: openwater, wetland and upland habitatsMarsh Study Measure flow of water and ENT from the Talbert watershed into the Talbert Marsh and from the Talbert M

44、arsh into the ocean.Measurements carried out for 15 days beginning May 2, 2000 Samples collected at 2 sites , Brookhurst and PCH Pump StationsENT MeasurementsHourly water samples collected from surface and bottom of water columnAnalyzed for ENT, pH, turbidity, and conductivityAlso collected bird fec

45、es to assess amount of ENT present.Bird census conducted to quantify input of ENT into the marshMarsh Parameters The 4 daily tide stages and the spring neap spring transition are evident in the water levelsWhen ebb tides occur during daylight hours, solar heating causes a significant increase in the

46、 temperature of the marsh water. ENT concentrations measured exceeded standards in 15% of samples taken at Brookhurst site and 46% at PCH Total number of birds that visited the Talbert Marsh during the study. Is Marsh ENT Source or Sink?All marsh data separated in 2 groups based on samples collected

47、 during ebb tides or flood tidesDuring ebb tides, the geometric mean of ENT and the percentage of samples exceeding the single sample standard approximately doubles as the water flows through the marsh from the Brookhurst to the PCH Station.The trend is reversed during flood tides when the Mean of E

48、NT and percentage of sample exceedences increase as water flows through the marsh from the PCH to Brookhurst Station.The results of this analysis identify the marsh, not urban runoff as the primary source of ENT in the water flowing into the ocean.Pollution from the marsh alone was sufficient to clo

49、se the beachENT generated in the Talbert Marsh appear to be at least partially responsible for the frequency with which surf zone samples in Huntington State and City beaches exceed state bathing water standardsConclusions based on 2 findings1. ENT Concentration are increased above standard as water passes through the marsh 2. And water flowing out of the marsh can be transpo