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UMASS/AMHERST STATE OF THE BAY 31E0bbDlt.5flt.7D3 1992 GOVERNiTiNT COCUf^ MAY 1*^1998 Massachus3n3 Universitv of Copy Depo^i^ory Waquoit Bay Watershed Falmouth, Mashpee, Sandwich Associationfor WaquoitBay Massachusetts thePreservation NationalEstuarine DepartmentofEnvironnnental ofCapeCod ResearchReserve Managennent CITIZENSFORTHEPROTECTION OFWAQUOITBAY,INC. PO.BOX3021.WAQUOIT.MA02536 INTRODUCTION V r aquoit Bay,located on the southernshore ofCape Cod, and itswatershed encompassingpartsofFalmouth, Mashpeeand Sandwich are the subjects ofour concern (seeFigure 1). Waquoit Bay, itswatershed and estuariesencompassan area ofapproximately20squaremiles. Thewatershedextendsfrom the mouthof Waquoit Bay toaboveSnakePond inSandwich,east toJehuPond in Mashpeeand west to AshumetPond in Falmouthand Mashpee. Approximately 2.5 square milesofthisarea is surface water. The land area of thewatershed crosses the political boundariesofFalmouth, Mashpee and Sandwich and encompasses the WaquoitBay National EstuarineResearchReserve ("WBNERR") anda section of theOtisAirForceBase. Asyou maybeaware,disturbing trendsarecomingtolightinWaquoitBaybased onresearchbeingconductedby scientistsaffiliated with theWaquoit BayNational Estuarine Research Reserve. These trendsare the subjectofthis paper. Briefly theyare: (1) decliningwaterquality, (2) decliningeelgrassbeds, (3) declining speciesabundance, and (4) increasingincidenceof "fishkills". Mountingevidenceindicates thatthese trendsresultprimarilyfromland usein the watershed. The watershed consists ofall land areas whichdrainintoWaquoit Bay via streamsand groundwater. What wedisposeofinourdrains, sinksand septic systemsand what weapply to ourlawnsand gardensas fertilizersand pesticidesenter thegroundwaterbelow. Groundwater flowsbeneath theentire watershed and eventuallyemptiesinto Waquoit Bay. Consequently, our land use practicesaffectnot only Waquoit Bay butdrinking water supplies and fresh waterpondsas well. In addition, runoff fromstreetsand otherpaved areascarriesbacteria and othercontaminants directlyinto ponds, rivers and Waquoit Bay. Theeffectsofourcurrent land use practicesarealreadyevident in Waquoit Bay. Letusexamineeachofthe trends. DECLINING WATER QUALITY 1: VVaquoit Bay isclearly suffering fromeutrophication, an increase in organic and mineral nutrientsin the water. Nutrients discharged into abay causeexces- sivealgaegrowth ("blooms") which floats in the water ("microalgae") and forms thick matson thebay floor ("macroalgae"). Algae reduces theclarityof the water and consequently theamountoflight penetratingthewatersurface. Although algaephotosynthesize during the day, producingoxygen, at nightoron overcast days they respire,consuminglargeamountsofoxygen. Thedecline in waterqualitydue to eutrophication has a number ofeffects. For example, thedecreasein water transparency impairs theability ofeelgrass togrow and maylead to a lossofeelgrassbeds which are important habitats fora variety offinfish and shellfish. In addition, thedecline in oxygen caused bybloomsof algae makes it difficult for some species to liveon the bay floor. In severecasesof oxygendepletion marineorganismsarekilled. 2 Figure 1:Land Use Types in the WaquoitBay Watershed 1 990 MacConneil Land Use (•) LMER study drainage basins Waquoit Bay Watershed i Comme r c i 0 1 (15. 16, 29) i C 1 e0red [, LV0-n d6.and26,Rec7,reo8t. i 90 [ZD R« » i <•en t i a 1 (10. 11 . 12. 113) ^FoAr9er iseu 1 t ur 0 1 (1. 2. 23. 21 i^Wet i 0ntd (3(). 14. 27. 28] y i n i n9 (5) BIiTWroasntse 0 I sp 0sai (19) portat ion (18] B0s i n Nome Basin Number Eel Pond ChuaisIhdnsetRivReirver ead of the Boy Hamblin Pond Jehu Pond Sage Lot Pond Sources Non-d i qsthieatfafC! audpaseti.anCgowdatCshCoeommammAulRtiCoss/m^sIaiiNt0qFennOdGiIb software G I S UacConnel Ignduse is from June 1990 o1 erial photo inter- ofetation (1:25,000 scale). Digipzed by the Resource UapDing - Land Information Systems Department of Forestry and WildliTe Uanagement, UAmnhievresrtsitiyn ocfoopUeorsastaicohnu swei1t1hs , the EOEA UassGIS project and the Cape Cod Commission. ThI* map tai prtductd by tht Capi Cetj Cemfflttiloti'i Steorophlc fAftrinotton S/sttm dtpartmdil for Iht AiteciatUn for tht PrtitrvoUon of Capo Cod. Doplctod boundarUt art apBroilmott agd ort Intondtd for planning purpeit* only. Thii map Ii not inltndtd to bt lutd for suryiy or ligal purpoiis. Stpttmbir \ti\ y«p er«it«d OB S/25/91 3 Thenutrientofgreatestconcern incoastal watersisnitrogen. Approximately 75% of thenitrogen enteringWaquoit Bayis from septic systemsincludingcurrently permitted Title5 systems(see Figure 2). Aspresentlydesigned, septic systems removebacteria butarenotcapableofremoving nitrogen. Fertilizers suchas those placed on lawnsarethe second majorsource representingabout 23% of thenitrogen enteringthebay. Because the numberofhousesin the Waquoit Baywatershed has increased tenfold from 785 in 1938 to over8000by 1984 (the most recentestimate available), nitrogenloadingisincreasing. In terms ofacreage, residential land use hasincreased from9% (1055 acres) of the watershed to approximately 22% (2638 acres). Adramatic increase inmacroalgaein watersadjacent to highlydeveloped land areassignals thatgroundwaterentering theestuaries iselevatingnutrient levels. Figure3 illustrates thisphenomenonbycomparing thegrowth rates of two speciesofmacroalgaein 3 subestuariesofWaquoitBay. Childsisdenselydevel- oped.SageLotcontainslittiedevelopmentand Quashnetisinbetweenin termsof housingdensity. Figure2:Sources ofNitrogen Entering a Shallow CoastalBayon Cape Cod mS«picSystem QLawnandAgncunjreFeftttzef BOlhat(AcdRain.Runo«) DatafromtheBuzzardsBayProject Figure3:Growth Rates ofMacroalgaein3 Subestuaries DatafromP.Peckol Childs Quashnet SageLot Graolaria Cladophora SpeciesofMacroalgae 4 Theexactcause-and-effectrelationshipbetween land usedevelopmentand the decline in waterqualityrequiresmoredetailed study. However, research to date showsaclearconnection. Perhaps what is mostalarmingis that the full impact of nitrogenloadingfromexistingsepticsystemshas notyetbeen realized. Because of thelengthoftheWaquoit Bay watershed and the flow rateofgroundwater moving within it, nutrients in groundwatercan takeanywhere froma few months to over30years to reach coastal waters. DECLINING EELGRASS BEDS 2: Als waterqualitydeclines, habitatsarealtered. Eelgrassbeds inWaquoit Bay are declining in size. In 1950, there wereapproximately200acresofeelgrass habitat. By 1987, 80% of theeelgrassbeds were lost with only40acres remaining. Eelgrassbedsarenurseryhabitatsfora varietyoffinfishand shellfish. Figure4:DecliningEelgrass Beds DatafromJ.Costa Oneagentcontributing to thedownturn in eelgrassacreage is theunusuallylarge massofalgae which results from the decline in waterquality caused bynutrient loading. Scientists have found thatexcessive nutrient loadingleads to large blooms ofalgaewhich reduce theamount oflight reaching theeelgrassand compete with eelgrass fornutrients. Microalgae floats in the watergiving the bay a greenish tinge, while macroalgae forms large matson thebay floor which occasionally float to the surface. Scientistshave found dense macroalgal accumu- lationsofone-to-two feetin only threefeetofwater in Waquoit Bay. Damage to eelgrass iscaused byboat propellorsin shallow water. Propellorscut through beds causingentireplants to be uprooted. Inaddition, boat traffic sus- pends sediments. This reduces sunlight reachingeelgrass, resulting in a decreased growth rate. Furthermore, research indicates that the suspension ofsediments leads to a declinein waterclarity. Thisputs eelgrassunderstress, makingit more susceptible to the "wastingdisease." Thewastingdisease, which occurred in theearly 1930sand nearly eliminated eelgrassbeds in the North Atlantic, isbelieved to becaused bya slime-mold-like protist, Labyrinthula. Afterdecades eelgrassbedsrecovered. Incontrast, the currentdecline ineelgrassbeds linked to eutrophication is unlikely to reverse unless steps are taken to reduce theamountofnutrientsentering the bay. 5 Associationfor WaquoitBay Massachusetts thePreservation NationalEstuarine DepartmentofEnvironmental ofCapeCod ResearchReserve Management CITIZF.NSFORTHEPROTrCTION OFWAQUOITBAY,INC. POriOX3021 WAOllOir MAOZSiS (t'