CHAPTER 3 THE MONITORING INDICATORS - NIWA 3_The... · 24 STREAM HEALTH MONITORING AND ASSESSMENT IT – CHAPTER 3 CONTENTS Introduction25 Visual clarity 26 Water temperature 27 Conductivity28

STREAM HEALTH MONITORING AND ASSESSMENT KIT – CHAPTER 3 23

CHAPTER 3

THE MONITORING INDICATORS

DRAFTSummer 2019–2020

STREAM HEALTH MONITORING AND ASSESSMENT KIT – CHAPTER 324

CONTENTSIntroduction 25

Visual clarity 26

Water temperature 27

Conductivity 28

Nitrate 29

Phosphate 30

E.coli bacteria 31

Periphyton 32

Macrophytes 33

Benthic macroinvertebrates 34

Fish 35

Current velocity 36

Streamflow 37

Stream habitat 38

Streambed composition 39

Rubbish 40



INTRODUCTIONInthischapter,threecategoriesofmonitoringindicatorsarepresented;waterquality,streamlife(aquaticplantsandanimals)andstreamhabitat.Beforeyoudecidewhattomonitor,itisimportanttoreadthroughthissectionandunderstandwhateachindicatorcantellyouaboutthehealthofyourstream.Streamlifeandwaterqualitydifferinsomeimportantways,andthereforetellusslightlydifferentthingsaboutthehealthofastream.

Water quality samples• reflectconditionsthroughoutthewhole

catchment:influencedbyallthewatersentering from different sources upstream

• a “snapshot” in time: may not capture a once-off pollutant spill, or extreme values that occur at a different time of day to your monitoring visits

• indicatewhatmaybepassedontodownstreamwaters(rivers,lakes,estuaries,thesea)

Stream life• respondmainlytothehabitatandwater

qualityimmediatelyaroundthem• canreflectconditionsoverweeksor

months:influencedbyconditionsthatoccurwhenyouarenotthere

• give a picture of overall stream health but itcanbehardtoknowwhatisaffectingthem most (because they respond to a widerangeofwaterqualityandhabitatconditions)

Monitoringwaterquality,streamlifeandstreamhabitatqualitytogethergivesthemostcomplete picture of overall stream health, and each indicator helps you to understand or interprettheothers.Forafewindicatorswehavetwolevels(methods)ofassessment.



VISUAL CLARITYWhy is it important?Visualclarityisameasureofunderwatervisibilityinstreams.Itreflectstheconcentrationsoffinesediment,algae,andotherparticlessuspendedinthewater.Reducedvisualclaritycanharmaquaticanimalsandriverbirdswhorelyonsighttofindpreyandavoidpredators,andswimmerswhomaynotseeunderwaterhazards.Reducedclarityalsomeanslesslightgettingthroughthewatertothestreambedwhereplantsneeditforphotosynthesis.Thefinesedimentthatcauseslowvisualclaritymayclogthegillsoffishandbenthicmacroinvertebrates.

How is it measured and reported?Visualclarityismeasuredusingaclaritytubeorblackdisc,whichbothmeasurethedistancethroughwaterthatahumaneyecanseeablackobject.Theresultsarereportedinmetres.Themeasurementvaluetobereportedistheaverageoftwomeasurements,thedistanceatwhichablackdiscdisappearsfromsightandthedistanceatwhichitreappears.Moststreamsarebestassessedbyviewingablackdiscinthestreamthroughanunderwaterperiscope.Thisequipmentworkswelldowntoabout0.1m(10cm)visibility.Ifyourstreamisveryturbid (<0.5mvisibility),theclaritytubeispreferredbecauseitismorepreciseandsafer(nowadingrequired).Visualclarityisstronglyinfluencedbystreamflow,andsoisverychangeableandshouldbemeasuredoneveryvisit(e.g.monthly).

What does it tell us?Lowvisualclarity(cloudywater)usuallytellsusthatfinesedimentsuchasclayandsiltparticlesaregettingintothestream.Humanactivities in the stream catchment (such as earthworksorlivestockgrazing)cangreatlyincreasetheamountoffinesedimentthatentersthestream.Lowvisualclarityisoftenaccompanied by faecal contamination, nutrients and other contaminants, so it may also indicate that levels of these contaminantsarehigh.



WATER TEMPERATUREWhy is it important?Aquaticanimalsstruggletoliveinwarmwater.InNewZealand,benthicmacroinvertebratescannotliveinwaterwarmerthanabout22°C,andfewaquaticanimalscansurviveabove30°C.Thisisbecausetheyareusedtolivinginwell-shadedforestedstreams,andtheyarenotusedtothehighafternoontemperaturesthatoccurwherethattreecoverisgone.So,smallstreamswithoutmuchshadingusuallyhaveonlyafewspeciesofaquaticanimals.Watertemperaturealsoaffectsmanyofthephysicalandchemicalcharacteristicsinstreams.Warmerwaterholdslessoxygenthancolderwaterandincreasesthesensitivityofaquaticanimalstotoxinsanddiseases(tworeasonswhyaquaticanimalsdieinwarmwater),andincreasestherateofchemicalreactionsandbiologicalprocessessuchasphotosynthesis.

How is it measured and reported?Singlemeasurementsoftemperaturearemadewithathermometer.Werecommendmeasuringwatertemperatureatthesametimeofdayoneachmonitoringvisit,andalwaysrecordingthetimethatyoumeasure.Thisisbecausewatertemperaturefluctuatesovertheday,reachingaminimumneardawnandmaximumintheafternoon.Asingletemperaturemeasurementmaynotbeveryinformative.Aseriesofmeasurementsovertimewillshowhowstreamwatertemperaturechangeswithweatherandseason,andallowyoutocompareyourstreamwithothers.However,evenaseriesofmeasurementsmaynotshowtheextremetemperaturesthatcausestressonaquaticlife.Forthat,youneedtomeasureatmid-afternoononthehottestdays-dayswithclearsunduringlatesummerwhenstreamflowstendtobelowest.Temperatureloggersareoftenusedtocapturethefullrangeofwatertemperaturesthatoccuroveradayandduringthehottestdays.Temperatureloggersaresettomeasuretemperatureatregularintervals(usuallyevery15to30minutes)forasetperiodoftime(usuallyweeksormonths).

What does it tell us?Manyhumanactivitiescanchangewatertemperatures, including:• dischargingwarmwaterfromthermal

powerstations• releasingwaterfromdams(releasing

bottomwatercanreducedownstreamtemperatures,releasingsurfacewatercanincreasethem)

• removing shade trees and shrubs from riparian areas

• changingwaterlevelsbyabstractionordiversionofwaterforirrigation,and

• connecting paved surfaces to streams via stormwaterpipes.



CONDUCTIVITYWhy is it important?Conductivityisameasureofhowwellthewatercanconductanelectricalcurrent.Conductivityincreaseswithincreasingsaltcontent(saltssuchaschloride,bicarbonate,sodium,calcium,)andincreasingtemperature.Eachstreamtendstohavearelativelyconsistentrangeofconductivity.Onceyouknowthisrange,youcanuseitasabaselinetocomparewitheachconductivitymeasurement.Alargeincreaseinconductivity(ifthewaterlevelhasnotchangedmuch)mightindicatethatadischargeorsomeothersourceofpollutionhasenteredastream.Thedissolvedsaltsmeasuredbyconductivityusuallydonothaveadirecteffectonstreamlifeuntiltheyreachlevelsfoundinbrackishwaterorseawater(greaterthanabout5,000µS/cm).

How is it measured and reported?Conductivity is measured using a conductivity meter and is reported in microSiemens per centimetre(µS/cm)(theoppositeofelectricalresistance).Becauseconductivityishigheratwarmertemperatures,thedisplayedvalueisadjustedtowhatconductivitywouldbeat25°C.Conductivitymeasurementsaremostusefulwhencollectedmanytimesoveralongperiod.Recordingthetypicalrangeofvaluesatdifferenttimesofyearandduringdifferentstreamflowconditionsallowsyoutonoticeanyunusualchangesoutsideofthisrange.

What does it tell us?Conductivityisoftenusedinwaterqualitystudiesasaquickindicationofthelevelofsaltcontent(includingnutrient“salts”)inthewater.Oneparticularuseisdetectingintrusionofseawaterorgeothermalwater,since both of these have much higher conductivitythanstreamwater.Ifyouarelookingforinangaspawningareas,thiscanhelpyoulocatetheendofthe“saltwaterwedge”whereinangausuallyspawn.Conductivity can also tell us something about wherethestreamwaterhascomefrom.High-conductivitystreamstypicallyhavemoreinputofgroundwater,withlongerundergroundflowpaths,thanlow-conductivitystreams.Ingeneral,however,conductivityishardtointerpretonitsown,andisnormallyusedtosupportotherinformation.Forexample,highconductivity may be a factor explaining high growthofperiphyton(algae)inastream,butyouneedtoconfirmthatallotherconditions(e.g.light,temperature,streamflow)aresuitableforgrowthandhaverecordedhighperiphytoncoverthere.



NITRATEWhy is it important?Nitrogenisanimportantnutrientsupportingplantgrowth.Nitrogeninsoilandwateriscycledthroughseveraldifferentforms,includingammonia/ammonium(NH3/NH4+),nitrate(NO3-),nitrite(NO2-)andorganicnitrogen.Nitratedissolveseasilyinwaterandcaneasilypassthroughsoils,particularlyduringheavyrainfall.Onceinastreamitcanbereadilyusedbyplantsandalgaeforgrowthandevenmoderateconcentrationscancauseplantsandalgaetogrowtonuisancelevels.However,theeffectsdependonvariousotherfactors,suchasphosphate(theotherimportantgrowthnutrient),light,floodfrequency,etc.Highnitrateconcentrationscanalsobetoxictoaquaticanimals,andtohumanhealth.Highnitrateconcentrationsindrinkingwaterhavebeenlinkedtoablooddisorderininfantscalledbluebabysyndrome.

How is it measured and reported?Nitrateconcentrationisusuallymeasuredusing“colorimetric”methods,wherechemicalsaddedtoawatersamplereactwiththenitratetoformacolour.Theintensityofthecolourshowstheconcentrationofnitrate.Professionallaboratoriesmeasurethecolourintensity(actually,theamountoflightabsorbedbythesample)usinganinstrumentcalledaphotometerorcolorimeter.InSHMAKyoureadthecolourintensitybyeyeusingacolourcomparator,sotheSHMAKmethodunfortunatelyislessaccuratethanprofessionalmethods.Nitrateconcentrationsareusuallyreportedinmg/L,whichisthesameasg/m3 or ppm (parts permillion).Normallyitis“mg/Lnitrate-nitrogen”(or“mg/LNO3-N”),butsometimesyoumightsee“mg/Lnitrate”instead.Thedifferenceisthatmg/Lnitrate-nitrogenmeasuresonlythenitrogenatomwhereasmg/Lnitratemeasuresthewholenitratemolecule,whichisheavier. 1mg/Lnitrate-nitrogenisthesameas4.42mg/Lnitrate.

What does it tell us?In agricultural catchments, high nitrate concentrations in streams typically result fromnitrogenfertilisersandlivestockthatexcrete large amounts of nitrogen in their urine.Nearhomesandresidentialareas,highnitratecanalsoindicateoverflowsorleakagefromsewagepipesorseptictanks,ororitcanbefoundinstormwaterinputs.Apart from toxic effects, the main concern withhighnitrateinstreamsisitseffectonstimulatingperiphyton(algae)ormacrophyte(aquaticplant)growth.Butbecausenitrogencancyclebetweendifferentforms,itishardtopredicttheeffectsofnitratewithoutalsoknowinghowmuchnitrogenisinthewaterinotherforms(e.g.ammoniumororganicforms).Highnitrogensuggeststhatnuisancegrowthsofperiphytonormacrophytesmightoccur,butotherfactors,suchaslowlight,lowphosphorus,lowtemperatureand/orfrequentfloods,maypreventnuisancegrowths.Togeta complete picture of nitrogen in your stream, werecommendsendingawatersampletoaprofessional lab for ammonium, nitrate, nitrite andtotalnitrogenanalysis.



PHOSPHATEWhy is it important?Phosphorusisanessentialgrowthnutrientforplants.Inwater,phosphorusoccursasphosphate(PO43-)whichhasbothorganicforms(derivedfromplantsandanimals)andinorganicforms(derivedfromrock).Mostphosphateentersstreamsattachedtosoilparticles,someofwhichsettleonstreambeds.Whileitisattachedtothissediment,thephosphateisnotimmediatelyavailableasanutrientforplantsandalgae.However,overtimeandintherightconditionsitcanbereleasedfromthesedimentasdissolvedphosphate,whichcanbetakenupbygrowingalgaeandaquaticplants.Evenatverylowconcentrationsphosphatecanstimulateplantgrowth.

How is it measured and reported?Likenitrate,phosphateconcentrationisnormallymeasuredusingacolorimetricmethod.Whenachemicalisaddedtothewatersample,itreactswithphosphatetoformabluecolourandtheintensityofthiscolourismeasuredusingaphotometerorcolorimeter.Likeaprofessionallab,theSHMAKkitusesacolorimeter(calledaphosphatechecker),butitislessaccuratethanaprofessionalcolorimeter,especiallyatlowconcentrations.Phosphateconcentrationisnormallyreportedinmg/L,whichisthesameasg/m³orppm(partspermillion).Becausephosphateconcentrationsinstreamsareoftenverylow,youoftenseeppb(partsperbillion)too.Partsperbillionis1000timesgreater,i.e.1ppm=1000ppb.TheHannaInstrumentsphosphatecheckerinSHMAKshowsphosphateconcentrationasmg/Lphosphate,butmostprofessionalsreportitasmg/Lphosphate-P.Thedifferenceisthatmg/Lphosphate-Pmeasuresonlythephosphorusatomwhereasmg/Lphosphatemeasuresthewholephosphorusmolecule,whichisheavier.Multiplyingyourcolorimeterresultsby0.326willconvertthemfromphosphatetophosphate-P,soyoucancomparethemdirectlywithmostprofessionallabresults.1mg/Lphosphateisthesameas0.326mg/Lphosphate-P.MeasuringdissolvedphosphateischallengingbecauseinmostNewZealandstreamsitispresentinverylowconcentrations(<0.01mg/L).

What does it tell us?Highphosphateconcentrationscanindicatehighlevelsofsoilerosionand/oruseofphosphatefertiliserinthecatchment.Inurbanenvironments high phosphate concentrations canresultfromwastewaterandstormwaterinputs, runoff from commercial cleaning or from phosphate fertilisation of gardens and playingfields.Themainconcernwithphosphateinfreshwaterisitseffectonstimulatingalgaloraquaticplantgrowth.However,itishardto predict these effects from the amount ofdissolvedphosphateinawatersample,assediment-boundphosphate(whichisdifficultforvolunteerstomeasure)mayalsocontributetoplantgrowth.Evenifallthe phosphorus is measured, it still may not beeasytopredicteffectsonaquaticplantgrowthforthesamereasonsasdescribedfornitrate.Togetamorecompletepictureofphosphateinyourstream,werecommendsendingawatersampletoaprofessionallabto analyse for phosphate (typically referred to asdissolvedreactivephosphorus)andtotalphosphorus.



E. coli BACTERIAWhy are they important?Faecalmicroorganismscomefromhumansandwarm-bloodedanimalssuchasfarmanimals,pets,birdsandpestmammals.Theycanenterstreamsinavarietyofwaysincludingdischargeorleakageofsewage,animalsdefecatinginthewater,orrunofffromgrazedpastures.Drinking,swimmingoreatingcertainfoods(e.g.,shellfish)fromwatercontaminatedwithfaecalmattercanmakeyousickfromtakinginhumanfaecalpathogenssuchasCampylobacter or Cryptosporidium.ThebacteriaEscherichia coli (E. coli),foundintheintestinesofwarm-bloodedanimals,isusedasanindicatorforfaecalcontamination.ThecommonstrainsofE. coli are not harmfulthemselves,butindicatethatharmfulpathogensmaybepresent.

How are they measured and reported?E. coliinwaterisreportedas“colonyformingunits”(cfu)in100mLofsamplewater.EachcolonyonagrowthplaterepresentsasingleE. coli cell, or a clump of cells, that has multiplied manytimesandbecomevisibletothehumaneye.E. colicanbegrownandcountedonaSelectE. coliCountPlate(SECplate).Thecolourofthecoloniesdependsonwhatbrandofgrowthplateyouuse.Thegrowthmediaontheseplatescontainsacombinationofnutrientsandcolour-producingchemicalsthatmake E. colicoloniesappearpurple-blue(MCMmedia)orblue(Petrifilm™).ColiformbacteriathatarenotE. coliappeargreen(MCMmedia)orpink/magenta(Petrifilm™).

What do they tell us?HighconcentrationsofE. coli bacteria suggest that pathogenic microorganisms might also be present in your stream and swimmingorwatersportsmaybeahealthrisk.E. coli,togetherwithrubbish,periphytonand visual clarity, measures the overall ‘swimmability’offreshwater.Sources of faecal contamination could be humans(e.g.leakingseptictanksorsewers),livestock,waterfowlor,inurbanareas,petwaste.Theriskofhumanpathogensdiffersbetweenthesedifferentsources.Forexample,theriskfromcattlefaecesisroughlysimilartohumansewage,whiletheriskfrombirdfaecesislikelytobelower.FurtherinvestigationwillbeneededtoworkoutthemostlikelysourceoftheE. coli you measured, andthehealthriskitrepresents.YourlocalregionalcouncilororganisationslikeESR(the Institute of Environmental Science and Research)maybeabletohelpwiththis.



PERIPHYTONWhy is it important?Periphyton refers to communities of algae and cyanobacteria attached to the sediment surface ortoaquaticplants.Periphytonvariesfromthinslipperyfilmstothickmatsorlongfilamentsinmanyshadesofgreenandbrown.Periphyton plays an important role in stream ecosystems by providing a food source for macroinvertebrates.Buttoomuchperiphytoncausesproblems.Thickgrowthslookugly,spoilrecreationalactivitiessuchasswimmingandfishing,andcanclogwaterintakesandfilters.Theycanalsosmotherhabitatformacroinvertebratesandstripoxygenfromthewateratnight,whichharmsmacroinvertebratesandfish.Onetypeofperiphyton(acyanobacteriaor“toxicalgae” called Microcoleus)cantaintdrinkingwaterwithamustyodourandevenproducetoxinsthathavekilleddogs.

How is it measured and reported?InSHMAK,youcanchoosebetweentwomethodsforestimatingperiphytoncoverage,dependingonthetimeavailableandyourequipment.Theresultsarereportedasthepercentageofthestreambedcoveredbyperiphytoninacertainarea.

The stone method (SHMAK Level 1)Examine 10–20 stones, one at a time• Doesn’trequireequipment• Quick

The viewer method (SHMAK Level 2)View10–20 areas of stream bed• Covers a larger area• Provides a more accurate estimate of

periphytoncoveracrossyourwholesite

Becauseperiphytongrowthchangesalotovertime,itisbesttomonitoriteverytimeyouvisitthesite(ideallymonthly)soyoucancalculateaveragegrowth.Monitoringperiphytonatthesametimeaswaterqualityisusefulbecauseperiphytonrespondstowaterquality(especiallynutrientsandtemperature).Themostimportantinformationaboutperiphytonisitsmaximumgrowth:howmuchperiphytonaccumulateswhenconditionsareideal(e.g.,stableflows,plentyofsunshine,andwarmtemperatures–conditionsthataremostlikelytooccurinlatesummer).

What does it tell us?MostsmallNewZealandstreamshavelittleobvious periphyton, because they are naturally shadedandtheperiphytonisquicklyeatenbybenthicmacroinvertebrates.Bloomsofnuisance periphyton are usually a symptom of a system stressed by factors such as nutrient enrichment, high light (from removal of banksidevegetation)andhightemperatures(thatincreasealgalgrowthratesandstresssomeinvertebrategrazers).Ifenoughlightis reaching the stream bed, nutrient levels tend to be the main factor limiting periphyton growth.Thismeansthatanincreaseinnutrientscancauseperiphytongrowthtoreachnuisancelevels(providedfloodsarenotfrequentandthestreamhasastonybedonwhichperiphytoncaneasilygrow).



MACROPHYTESWhy are they important?Macrophytesarelargeaquaticplants,often(butnotalways)withleavesandroots.Inmuddyorsandy-bottomstreamstheyarenormallythemaintypeofaquaticplant(whereasperiphytonisthemainplanttypeinstony-bottomstreams).Macrophytesproduceoxygen,providerefugeforfishandsubstrateforbenthicmacroinvertebratesandcontributetonutrientcycling.However,toomuchmacrophytegrowthcanimpactonhumanvaluesbyaffectingswimmingorfishing,causingflooding,cloggingwaterintakes,depletingdissolvedoxygenlevels,smotheringthestreambedandcausingfinesedimenttosettleonthestreambed.Somemacrophytes,suchasoxygenweed,areclassedasinvasive(ornoxious)weedsbecausetheyquicklyinvadenewareasandformlargedensebedsthatchokewaterwaysandexcludeotherplantandanimalspecies.

How are they measured and reported?Therearetwomacrophyteindices:• The“macrophytewatersurfacecoverindex”estimatestheamountofwatersurfacearea

occupied by macrophytes• The“macrophyteclogginessindex”estimatesthepercentageofthewatervolumethatis

occupiedbymacrophytes.

Macrophytesarereportedastheaveragecoverofmacrophytesatyoursite(asapercentage).Sincemacrophytesrequiresomesoftsediment(sandormud)theyaretypicallyassessedinsoft-bottomstreamsonly.However,somespeciescanberootedinthestreambankandgrowacrossthewatersurfaceinsmallerhard-bottomstreams.Macrophytescanbemonitoredonceperyearinsummer,whentheirgrowthisatitspeak.Butmonitoringalsoinspringandautumn,providesmoreinformation,whichcanbehelpful.

What do they tell us?Theamountofmacrophytecoverinastreamtellsushowsuitabletheconditionsforgrowthare.Theseconditionsincludetheamountoflight,floodfrequency,flowvelocity, and nutrient concentrations in the waterandsediments.Nuisancegrowthsofaquaticmacrophytesaregenerallymostcommoninunshaded,nutrient-richlowlandstreams.Nutrientrunofffromtheland,aswellasinputsfromsewageandstormwaterdischarges,canpromotemacrophytegrowth.Increasing stream lighting to >30% of full sun,(e.g.,byremovingriparianvegetation),willtypicallyresultinnuisancegrowths.Conversely, restoring riparian forest can limit growthsofpestspecieswhileenablingshade-tolerantnativespeciestosurvive.Thetwomacrophyteindicesindicateimpactonstreamflow,recreationaluseandecologicalhealth.Highmacrophytecovercanharmaquaticanimalsbyreducingdissolvedoxygenduringthenightwhentheyrespire;measuring minimum dissolved oxygen (typicallyneardawn)canhelpdetermineifthisisoccurring.



BENTHIC MACROINVERTEBRATESWhy are they important?Benthicmacroinvertebratesareanimalsthatliveatthebottom(benthic)ofstreamsandlakes,arelargeenoughtobeseenwiththenakedeye(macro)andlackabackbone(invertebrate).Weoftencallthemstreambugsforshort.Infreshwaters,theyconsistoftheimmaturestagesofmanyinsectssuchflies,mayflies,caddisflies,stoneflies,beetlesanddamselflies.Aswellasinsects,therearealsocrustaceans(e.g.kōura/crayfishandshrimps),snails,wormsandleeches.Streambugsareakeypartofstreamfoodwebs,feedingonperiphyton,macrophytes,deadwoodoreachother.Theaquaticlarvaeareanimportantfoodsourceforfishandthewingedadultsareofteneatenbybirds.

How are they measured and reported?

SHMAK level 1 SHMAK level 2 SHMAK level 2

Stream type Stony-bottom Stony-bottom Sandy/muddy-bottom

Equipment Sieve Kick-net Kick-net

Method Collect individual stones

Disturbthestreambed to dislodge macroinvertebrates

Jab vegetation, brush logsandwood

Advantages Quickerthankick-net More accurate More accurate

Disadvantages Misses some species Timeconsuming

Aftercollecting,thedifferentbugtypesareidentified.Eachtypehasa“tolerancescore”from1to10thatindicateshowsensitiveitistowaterpollutionorhabitatdegradation(10meansonlyfoundinhealthystreams,1meansoftenfoundinpoorconditions).Thedifferentscorescanbecombinedandreportedinoneormoremacroinvertebratehealthindices.OneindexcommonlyreportedbyprofessionalsintheMacroinvertebrateCommunityIndex(MCI).

What do they tell us?Because the tolerance of each macroinvertebrate type to environmental impactsiswellknown,theparticularvarietyof bugs present in a stream can tell you about environmentalconditionsthere.However,itmightnottellyouwhichenvironmentalfactoriscausingsomebugstobemissing.Undertakingahabitatassessmentandwaterqualitymeasurementsatthesametimecanhelpyouworkthisout.Streambugsliveinstreamsformonthsoryearssotheyreflectarangeofhabitatandwaterqualityconditionsoveralongperiodoftime,whereaswaterqualitymeasurementsmeasureonlyonetypeofimpactatonepointintime.

IntheSHMAK,macroinvertebrates are sampled using asieveorakick-netasoutlinedbelow.



FISHWhy are they important?NativefishareanimportantpartofNewZealand’sfreshwaterbiodiversity.NewZealandhasapproximately53nativespeciesoffreshwaterfish(althoughtheexactnumberofspeciesisunderreview),mostofwhichareendemic(foundonlyinNZ).Mostspeciesaredeclininginnumbersacrossthecountryandsomearethreatenedwithextinction.Fishplayanimportantroleastoppredatorsinhealthystreamecosystems.Thespeciespresentandtheirabundanceaffectsabundancesofstreambugsandsomeecosystemprocesses.

How are they measured and reported?Thethreemainsamplingmethodsforestimatingfishnumbersinastreamarebackpackelectrofishing(picturedtopleft),trapping(withfykenetsorGeeminnowtraps)andspotlighting.SpotlightingisthemethodrecommendedintheSHMAKbecauseitrequirestheleastspecialisedequipment.

Spotlighting(recommendedinSHMAK):SpotlightingisthemethodrecommendedintheSHMAKbecauseitrequirestheleastspecialisedequipment.Spotlightinginvolvesshiningapowerfulspotlightintothestreamreachatnightandrecordingwhatspeciesareseen.Itissuitableforwadeablestreamsbecausemanyfreshwaterfishspeciesarebenthic(bottom-dwelling)andnocturnal(moreactiveatnight).

Trapping:TrappinginvolvessettingafykenetorGeeminnowtrapalongthestreamreach,leavingitoutovernightandretrievingitthenextmorning.Thismethodisaviablealternativeoptionifworkingwithacouncilorcommunityorganisationthatcanpurchasetheequipment.

Electrofishing:Electro-fishing,whichusesanelectriccurrenttotemporarilystunfishsothattheycanbeassessed,mustbecarriedoutbyatrainedprofessional.

Whichever method is used, the types and numbers of each species caught are usually recorded intheNewZealandFreshwaterFishDatabase.Fishsurveysarebestundertakenduringthesummer(DecembertoMarch)asfishgenerallybecomelessactivewhentemperaturesarelow.Theoptimaltimeforsamplingiswhenflowsarestableandat(orcloseto)baseflow.Samplingwithin5daysafterafloodisusuallyavoided.Fishdataareusuallyreportedassimplyalistoffishpresent(withtheirabundancesandsizerangeifmeasured).ThereisanindexcalledtheFishIndexofBioticIntegrity,whichincreaseswithmorenativefishspeciespresentanddecreaseswithmorepestfishpresent.

What do they tell us?Therangeofnativefishpresentcantellusaboutthehabitatandwaterquality,bothatyoursiteandbetweenyoursiteandthesea.Also, because about a third of native species spend some part of their lives at sea, they needuninterruptedpassagebetweentheseaandtheirfreshwaterhabitatstocompletetheirlifecycle.Therefore,speciesmaybeabsent if there is: • habitatloss(includinglossofwater,

riparian vegetation, large instream featureslikebouldersandwood,orinfillingofthegapsbetweenstreambedcobblebyfinesediment)

• abarriertomigration(e.g.,culvertsanddams)

• lowdissolvedoxygenlevels• high temperatures• lowfoodresources(benthic

macroinvertebrates)or• predatoryintroducedfishpresent.

Toknowwhatfishspeciesareabsentyouwillneedtoknowwhatspeciesshouldbethere.SamplinganearbyreferencesiteorcheckingtheNZFreshwaterFishDatabase(https://nzffdms.niwa.co.nz/)couldhelp,butbestwouldbetodiscusswithafishexpert,suchasatyourregionalcouncil.



CURRENT VELOCITYWhy is it important?Currentvelocityisthespeedatwhichthewatermovesinthestream,andisakeyaspectofaquatichabitat.Afastcurrenthelpsplantstotakeupnutrientsandanimalstotakeupdissolvedoxygenfromthewater.Anditbringsmorefoodtoaquaticanimalsthanaslowcurrent.Sofast-movingstreamsoftencontainahigherdiversityofmacroinvertebratesandfishthansluggishstreams.However,watervelocityalsoexertsadirectforceonplantsandanimals,soaveryfastcurrentcanstopperiphytonandmacrophytesfromreachinghighabundances.Highvelocitiesduringfloodscanflushoutfish,dislodgestreammacroinvertebratesanduprootmacrophytes.Periphytonmaybescouredoffrocksduringhighvelocitiesbythewateritself,byabrasionofmovingsediment(sandblasting)orbytherocksbeingrolledover.

How is it measured and reported?Surfacevelocitycanbemeasuredfromtheratethatafloatingobject(e.g.,anorange)movesalongameasuredlengthorsectionofstream..Itisbesttomeasureinarunsectionwhereflowisfairlyuniformandtherearenotmanyobstructions.Thismethodgivesonlyaroughmeasureofaveragevelocitybecausewatermovesatdifferentspeedsindifferentplaces:itisfasternearthesurfaceinmidstreamandslowernearthestreambedandbanksduetofriction.Averagevelocityacrossthewholestreamisnormallyabout86%of the surface velocity you measure, so you can calculate average velocity by multiplying by 0.86.Professionals typically use a current meter to measure velocity at different depths then calculate averagevelocityfromthese.Currentvelocityisreportedasdistanceperunittime(e.g.,metrespersecondorm/s).

What does it tell us?Velocity can be multiplied by stream cross-sectionalareatocalculatestreamflow(see“Streamflow”sectionopposite).Also,ifyouhave measured velocity on every monitoring visit,itcanbeusedonitsown,orwithwaterlevel,asarelativemeasureofstreamflow.Velocity indicates the potential for material (e.g.,rubbish)tobetransporteddownstream.



STREAMFLOWWhy is it important?Streamflow(discharge)isthevolumeofwaterperunittimeflowingpastapointinthestream.Itisakeymeasureofthesizeofthestreamandof“stateofflow”–howtoday’sflowcomparestotheaverage.Thestreamflowatthetimeofyourmonitoringvisitisimportantforunderstandingthewaterqualityonthatday,aswaterqualitydependsstronglyonstreamflow.Therefore,itisimportanttoestimatestreamflow,oratleastwaterlevel,oneverymonitoringvisit.Thestreamflow“regime”ofastream(medianstreamflow,meanstreamflowandotherstatistics)describeshowmuchastreamchangesovertime,usuallyinresponsetorainfallorsnowmelt.Averychangeablestreammaybeamoredifficulthabitatforaquaticplantsandanimalstoliveinthanamorestablestream.

How is it measured and reported?Waterlevelmeasurementscanprovideaqualitativeestimateofstreamflow.Waterlevelcanbedescribedaslow,normal,slightlyraisedorhigh.Ifyouarefamiliarwiththestream,youcanjudgewaterlevelfromyourownexperience.Ifyoudon’tknowthenormalwaterlevel,thenyoucanjudgeitinrelationtoperennialterrestrialplantsandthestreambanks.Ifthewaterisfarbelowtheperennialplantsandthewaterisclearerthanusual,thewaterlevelislow.Ifthestreamisfloodingoverbanksorovertherootsoftreesandshrubs,thewaterlevelishigh.Measuringstreamflow(inm³/s)givesmoredetailedinformationthanestimatingwaterlevel.Forlong-termmonitoringsites,thebestapproachisusuallytofindanearbysitesuitableforinstallingastaffgauge(similartoaverticaltapemeasureonapole)toindicatewaterlevelonyourstreamvisits.Waterlevelcanbeconvertedtostreamflowbydevelopingandmaintainingaratingcurve.Alternatively,youcanestimatestreamflowbymeasuringcurrentvelocity(seeCurrentVelocitysection)andcross-sectionalareaofthestream.Cross-sectionalareaiscalculatedbymeasuringwaterdepthsat5-10equally-spacedpointsacrossthestreamchannelandmultiplyingtheaveragedepthbythestreamwidth.Keepinmindthatwaterlevelorstreamflowmeasurementsmaycollected(orestimated)byyourregionalcouncil.

What does it tell us?Streamflowonthedayof(and1-2daysbefore)yourmonitoringvisithelpsyoutounderstandthewaterqualityyoumeasuredthatday,becausemostwaterqualityindicatorschangewithstreamflow.Forexample,visualclarityisusuallylowathighstreamflowandwaterisclearatlowstreamflow.Thestreamflowinthedaysorweeksbeforeyour monitoring visit may help explain your results for periphyton, and may tell youwhetheritisasuitabletimetosamplemacroinvertebrates.



STREAM HABITATWhy is it important?Streamhabitatisdefinedasthewholestreamenvironmentincludingthestreambed,streambanksandlanduseintheimmediatevicinityofthestream(riparianzone).Itisformedbytheinteractionbetweenseveralfactors,includingtopography(shapeoftheland),geology,climate,andland-use.Thetypeandqualityofthisphysicalhabitathaveasignificantinfluenceonthestreamplantsandanimalsbecauseeachspeciesneedsasuitable“livingspace”tosurvive.Eachspeciesprefersdifferenthabitatconditions(e.g.somespeciespreferfastmovingwater,othersquietpools).Streamhabitatprovides:• a place to live• shelterfromhighflows• protection from predators• aplacetolayeggs.

How is it measured and reported?Streamhabitatcanbeassessedseveralways,rangingfromvisualobservationstodetailedmeasurements.InSHMAKwescoreeightdifferentaspectsofthestreambed,banksandriparianzone.Eachaspectisassessedvisually,bymatchingyoursitetodescriptionsthatreflectacontinuumofconditionsfromexcellenttopoor.Thisapproachrequiresnoequipmentexceptatapemeasure.Becausestreamhabitatchangesslowlyundernormalconditions,itonlyneedstobemeasuredonceperyear.However,itiswisetore-assessafteralargestormornewearthworksorconstructionactivities.

What does it tell us?Stream habitat assessments tell us about various human activities that may have degradedstreamhabitat(e.g.,theremovalofriparianvegetation,causingstreambankerosion, increased sedimentation, and smotheringoffishhabitat).Poorhabitatconditions could cause a greater impact on streamlifethanpoorwaterquality.Therefore,assessinghabitataswellaswaterqualityisnecessary to interpret the results of biological monitoring.Identifyingwhichhabitatfeaturescouldbeaffectingstreamhealthwillhelpyousetgoalsforrestoringstreamhealth.Monitoringstream habitat over time can also help you evaluate the success of your restoration efforts.



STREAMBED COMPOSITIONWhy is it important?Thecompositionofthestreambed(thetypeandsizeofparticlesthatmakeupthebed)hasastronginfluenceonstreamlife.Streambedsmadeupmostlyofbouldersandcobblesprovidehardsurfacesthatstreambugsneedtocrawlonorunder.So,theysupportagreaterrangeandhighernumbersofstreambugsthanbedsmadeupoffinesedimentslikesilt.Cobblesandbouldersalsoprovidegoodhabitatfornativefish,creatingspaceswherethefishcanshelter,feedandnest.Finesediment(sandandmud)depositedonastonystreambedcansmotherthehardsurfacesmacroinvertebrateslike,fillupthespacesthatfishuseandclogtheirgills.

How is it measured and reported?ThemostcommonmethodtoestimatestreambedcompositionistheWolmanwalk(SHMAKLevel2).Randomlyselectedstreambedparticlesarepickedup,measuredandthedifferentsizeclassescounted.Aquickermethodisavisualassessment(SHMAKLevel1),whichcanbemadebywalkingupanddownyourstreamreachandestimatingtheproportionofthestreambedcomposedofeachthecategoriesgiven.ThisgivesarougherestimatethantheWolmanmethod.Streambedcompositiontypicallychangesslowlysoonlyneedstobemonitoredannually,ideallyatthesametimeasyoucollectyourbenthicmacroinvertebratesample.Butitcanbeusefultore-assessafteralargestormornewdevelopmentinthecatchment.Streambed composition is reported as the percentage of the stream bed that is covered by differentcategoriesandsizeclassesofparticles.Streambedparticlesrangefrommudorsand(<2mm)toboulders(>25cm).Thestreambedmayalsobecoveredbyleaves,wood,macrophytes(aquaticplants),concreteorbedrock.

What does it tell us?Streambedcompositiontellsuswhatsortofaquaticlifewecouldexpecttosee(providedwaterqualityandflowsaresufficient).Italsotells us both about the natural setting of a stream(catchmentgeologyandtopography)andabouthumaninfluences.Streamsinsteepheadwaters,incatchmentswithhardrocktypes,andthoseexperiencingfrequentlargefloodsusuallyhavebedsdominatedbylargeparticles(cobblesandboulders).Streamsinlowland,low-gradientvalleys,incatchmentswithsoftsedimentaryrocksand/orhavingfloodstendtohavebedsoffinesediment.Acoveringorbuild-upoffinesediment can also indicate soil erosion in thecatchmentorstreambanksmadeworsebyhumanactivitiessuchasearthworksorfarming.



Why is it important?Thepollutionoffreshwatersbyhouseholdandcommercialwasteisagrowingconcern.Rubbish:• makesstreamsunattractive• canmakethemunsafeforrecreation

–brokenglassordiscardedappliancescanbesharpordangerous–discardedchemicalcontainerscanleaktoxiccontaminants–sometypes(e.g.soilednappies)canspreadhumanpathogens

• canharmwildlife–animalscanbecometrapped,strangled,ormayeatsomeitems.

Muchoftherubbishiseventuallytransporteddownstreamtoestuariesorouttoseawhereitcontinuestoharmtheenvironmentandpollutebeaches.

How is it measured and reported?A simple visual assessment can be made by estimating the amount of different rubbish types inandaroundastreamreach.InthisSHMAKLevel1method,severalaspectsofrubbisharescoredonascaleof1to8andsummedtogiveafinalscoreoutof40:

Overallamountofrubbish 8 7 6 5 4 3 2 1

Threattoaquaticlife 8 7 6 5 4 3 2 1

Threattohumanhealth 8 7 6 5 4 3 2 1

Amount coming from on-site dumping 8 7 6 5 4 3 2 1

Amount accumulating from upstream 8 7 6 5 4 3 2 1

Total Score out of 40

Foramorecomprehensiveunderstandingofwhatrubbishisthereandwhereitiscomingfrom,therubbishtallymethodisused.InthisSHMAKLevel2method,rubbishitemsareidentifiedandcountedbymaterialtype(e.g.,glass,metal,plastic)anduse(e.g.,foodwrappers,metalappliances).Theycanthenbeweighed,andareremovedfromthesite.Werecommendassessingrubbishonceperyear,oronceeachseasonifyouwanttodeterminetheratethatrubbishaccumulatesinyourstreamreachindifferentseasons.

RUBBISHWhat does it tell us?Assessing rubbish in streams can tell us wherelitteringordumpingisoccurring,canraiseawarenessofrubbishissuesandshowwherebetterwastemanagementstrategiesareneeded.Beawarethattherubbishmayhavebeendroppedupstreamorelsewherein the catchment, and carried to your site by rainorwind.Rubbishsurveysusingthetallymethodcanbelinkedwithnearbycoastalsurveys of beach litter to help estimate the types and amount of rubbish exported out to sea.Ifyoucompletelyremovealltherubbishat your site and revisit the site regularly, thenyoucanworkouttheaccumulationrate(numberofpiecesperday)fromyourdata,and compare accumulation rates at different streamsites.


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CHAPTER 3 THE MONITORING INDICATORS - NIWA 3_The... · 24 STREAM HEALTH MONITORING AND ASSESSMENT IT – CHAPTER 3 CONTENTS Introduction25 Visual clarity 26 Water temperature 27 Conductivity28