Presentation on theme: "Clearwater River Habitat/Bioassessment"— Presentation transcript:
1Clearwater River Habitat/Bioassessment ByCorey HansonWater Quality CoordinatorRed Lake Watershed District
2Clearwater River Habitat/Bioassessment The Clearwater Nonpoint Study identified a need for a detailed habitat/bioassessment on the Clearwater RiverSampling completed in August 2003Index of Biotic Integrity (IBI)Scores a 100 meter reach of a river based upon a set of standardized metricsDifferent Types of IBIsFishMacroinvertebrateHabitat
3Methods UsedEPA Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates, and FishBarbour, M.T., J.Gerritsen, B.D. Snyder, and J.B. Stribling. 1999
4Site Selection More targeted than probabilistic. Sites were associated with water quality monitoring stations and access points along the river.Sites needed to be wadeableReaches were located upstream of bridges in order to minimize (although arguably not eliminate) the influence of the bridge.100 ft between starting point of reach and the bridge.
6Site SelectionFor this study, tried to pick some sites that were minimally impacted, such as sites 3 and 4 in the NLF ecoregion, 6 in the NCHF ecoregion, as well as 14 and 15 in the RRV ecoregionSome sites on channelized sections of the river were picked to show the effect of channelization on habitat and aquatic life
7Fish Sampling Backpack electrofishers Fish identified, weighed, and counted in the field
8Fish Sampling Scores based upon Number of natives Number of native dartersNumber of native sunfishNumber of native suckersNumber of intolerantsPercentage of tolerantsPercentage of omnivoresPercentage of insectivoresPercentage of piscivoresPercentage of hybridsPercentage of abnormalitiescatch rate
10Clearwater River Habitat/Bioassessment Macroinvertebrates D-Frame NetsSame area sampled at each site (# of jabs)Habitat types sampled proportionallyRifflesWoody DebrisVegetationSamples preserved in 99% Isopropyl AlcoholSorted, Counted, Identified
11Clearwater River Habitat/Bioassessment Habitat AssessmentScores based on 10 metricsEpifaunal substrateEmbeddednessVelocity/depth regimesediment depostionchannel flow statuschannel alterationfrequency of riffles or bendsbank stabilityvegetative protectionriparian vegetative zone width
15Clearwater River Habitat/Bioassessment – Zooplankton Sampling Plankton NetPreserved with 99% Isopropyl AlcoholAnalyzed by MNDNR Aquatic Invertebrate Biology Lab
16Clearwater River Habitat/Bioassessment – Vegetation Mapping
17Positive and Negative aspects of Methods Used PositivesStandardAvailable, easy to understandResults comparable if same methods are usedRepeatable – sites are easy to locateNegativesHabitat assessment open to subjectivity, personal judgements on %’sSubsampling of macroinvertebrates can exclude species that don’t occur in abundance such as Nepidae and BelostomatidaeMetrics used may differ among IBI studiesDiffering techniques of samplers could effect results
18Reference Condition Discussion The presence of a bridge may technically rule out the use of any of our sites as reference sites, but the data can be used to find areas in which reference sites may be found (upstream of reaches that scored well in this study)There were some reaches where the bridge downstream of the reach was the only anthropogenic factor “impacting” the streamIs there an acceptable buffer between a monitored reach and impoundments, bridge areas, and large tributary confluences?Do bridges affect some IBI types more than others (fish more than macroinvertebrates and habitat)?
19The End Corey Hanson Water Quality Coordinator Red Lake Watershed District