Table Of ContentUMASS/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'
