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WATER QUALITY IN THE EFA PROCESS. Jay O’Keeffe, UNESCO-IHE Institute for Water Education. WATER QUALITY. Efficient functioning of river ecosystems requires provision of suitable hydrological regime and water of suitable quality 2 aspects of water quality:
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WATER QUALITY IN THE EFA PROCESS Jay O’Keeffe, UNESCO-IHE Institute for Water Education
WATER QUALITY • Efficient functioning of river ecosystems requires provision of suitable hydrological regime and water of suitable quality • 2 aspects of water quality: • How will modified flow regimes affect water quality? (Incorporate in env. flow recommendations) • What have human activities in the catchment done to modify the present water quality from natural conditions? (Rehabilitation measures at source)
WATER QUALITY IN THE BBM METHODOLOGY • Key questions: • Impact of flow on water quality • Impact of water quality on riverine biota • Difficulties in assessment of water quality aspects in BBM • Sporadic data availability • Water quality models often not available • Biota response affected by a range of synergistic and antagonistic effects, rate of concentration change and acclimation
Water quality variables • Required: • Physical and chemical water quality conditions • How these conditions change seasonally / yearly • Similar data in non-impacted state • System variables: pH, Temp, O2 • Non-toxic constituents: EC/TDS, TSS, cations (NA, K, Ca, Mg) and anions (SO4, Si, alkalinity) • Nutrients: total P, total N, NO3, NH4, NH3, NO2, TOC • Toxic constituents: metals, pesticides, other
PROTOCOL FOR INCORPORATING WATER QUALITY IN EFA • Preparation for the workshop • Identify broad climatic region and ecoregion • Take note of geomorphological reaches • Identify significant hydrological features • Delineate reaches / segments with expected similar water quality • Establish reference / natural conditions • System variables, nutrients, toxic chemicals
PROTOCOL FOR INCORPORATING WATER QUALITY IN EFA (cont.) • Preparation for the workshop (cont.) • Determine present water quality status • Use water chemistry data • Identify likely threats (sources of contaminants) • List potential point sources of contamination • Identify major land use areas • Assess the data (completeness of data) • Prepare the report
PROTOCOL FOR INCORPORATING WATER QUALITY IN EFA (cont.) • Roles and responsibilities (at workshop): • In absence of water quality modeling, make predictions with regard to effect of flow changes on water quality • Based on examination of cross-sections and hydraulic characteristics • Advise on flows that should maintain required EMC
MINIMUM DATA SET • Seasonal (three-monthly) water chemistry and biomonitoring data over complete annual cycle • If data not exist: • Make extrapolation from adjacent and comparable river reach, or • Derive data from reference site
CONCLUSIONS • For aquatic ecosystems to function adequately, not only appropriate flows of water, but also of suitable quality are required • Assessment of water quality requirements for riverine ecosystems entails considerable degree of subjectivity