Genki Terauchi September 11, 2008 NOWPAP CEARAC

Transcription

1 Development of Draft Procedures for assessment of eutrophication status including evaluation of land based sources of nutrients for the NOWPAP region and a case study in Toyama Bay Genki Terauchi September 11, 2008 NOWPAP CEARAC 1

2 Needs to develop common procedures for assessment of eutrophication status Eutrophication in the Northwest Pacific region is a major environmental issue today To solve this issue, understanding and assessing eutrophication status is important However, method for assessment of eutrophication status differ from country to country, and there is no common method. Regional assessment is required to consider most appropriate regional monitoring or countermeasures against eutrophication 2

3 Methodology of developing common procedures for assessment of eutrophication status Review and refinement by experts of NOWPAP member states Harmonization and compilation of results of the review and refinement by a consultant Lesson learned from a case study in Toyama Bay (Phase 1) Methodology development 3 Draft procedures for assessment of eutrophication status for the NOWPAP Region Aug, 2008 Continuation of a case study in Toyama Bay (Phase 2) Assessment of eutrophication status by the Draft Procedures Procedures for assessment of eutrophication status for the NOWPAP Region

4 Objective of the case study To help develop an objective eutrophication assessment procedure for the NOWPAP region To help establish an effective assessment and verification tool for assessment of eutrophication by utilizing remote sensing techniques 4

5 Structure of the case study 5

6 1. Scope of assessment Collection of relevant information Regular water quality monitoring data of Toyama Prefecture Supplementary water quality monitoring data of Toyama Prefecture Fishing ground monitoring data of Toyama Prefecture Remote sensing data Eutrophication related survey and research Others 6

7 1. Scope of assessment Division of assessment area into subareas The assessment area was divided into sub-areas to enable more local-scale assessment Sub-areas of the case study 7

8 1. Scope of assessment Selection of assessment parameters Parameters were selected based on their data reliability and continuity Category Assessment parameter I Degree of nutrient enrichment II Direct effects of nutrient enrichment III Indirect effects of nutrient enrichment IV Other possible effects of nutrient enrichment Nutrient load Nutrient concentration (annual) Nutrient concentration (winter) Chlorophyll-a concentration Oxygen deficiency Fish kill Organic carbon/organic matter Plankton blooms Algal toxins Riverine input (T-N, T-P) T-N, T-P Winter DIN & DIP Winter DIN/DIP ratio Field data & remote sensing data DO Abnormal fish kill incidents COD Red-tide events (Noctiluca spp.) Shellfish poisoning incidents 8

9 2. Data Processing Organization of collected data Screening and sorting of data into sub-areas Sorting of data into sub-areas based on locations of monitoring site Excluded of unsuitable data (e.g. data by no standardized analytical methods) Data processing of assessment parameters Calculation of assessment value of each assessment parameter (annual mean, annual max., winter mean, etc.) Calculation of assessment data of each assessment parameter (e.g. 3-year mean of assessment value) 9

10 3. Setting assessment criteria Identification tools for assessment data Off shore Background Comparison Monitoring site By comparison By occurrence By Trend 10

11 3. Setting of assessment criteria Combination of identification tools used for each assessment parameter Assessment parameter Assessment value Comparison Identification tool Occurrenc e Trend I Riverine input (T-N, T-P) Annual mean T-N, T-P Annual mean Winter DIN & DIP Winter mean Winter DIN/DIP ratio Winter mean II Chlorophyll-a (field data) Annual max./mean Chlorophyll-a (remote sensing data) Annual max./mean Red-tide events (diatom spp.) Annual max./mean Sea area ratio with high chlorophyll-a (remote sensing data) Annual no. events III DO Annual min. Abnormal fish kill incidents Annual no. events COD Annual mean IV Shellfish poisoning incidents Annual no. events Red-tide events (Noctiluca spp.) Annual no. events 11

12 3. Setting of assessment criteria Classification of each assessment data by identification tools Identification by Comparison and occurrence 12 Current status High status & Decrease trend Low status & Decrease trend Decrease trend High status & No trend Low status & No trend No trend Identification by trend High status & Increase trend Low status & Increase trend Increase trend Trend

13 3. Setting of assessment criteria 9 Classifications for each assessment parameter 13

14 3. Setting of assessment criteria Identification criteria of comparison identification tool Score Identification results Identification criteria + Relatively high b/a>1.1 (upper 33%) - Moderate b/a>1.1 (under the upper 33%) - Similar or lower than background b/a 1.1 b: average of last 3-years a: background value Identification criteria of occurrence identification tool Score Identification results Identification criteria + Occurrence More than one occurrence in the last 3- years - Non-occurrence No occurrence in the last 3-years Note: The above identification tools were used to identify the current status of the assessment parameter 14

15 3. Setting of assessment criteria Identification criteria of trend identification tool Score Identification results Identification criteria + Significant increase Statistically significant increase identified by t-test (significance level=5%) No significant increase/decrease No statistically significant increase or decrease identified by t-test (significance level=5%) - Significant decrease Statistically significant decrease identified by t-test (significance level=5%) Note: The above identification tool was used to identify whether there was any statistically significant increasing or decreasing trend in eutrophication 15

16 3. Setting of assessment criteria Classification criteria for each assessment category Example of category II in sub-are B Pick one representative result to determine assessment result of each category 16

17 3. Setting of assessment criteria Classification criteria of the assessment area/sub-area Holistic assessment criteria were set for the assessment area/sub-area so as to diagnostically explain classification results of each assessment parameter and category. 17

18 4. Assessment process and results Assessment results (e.g. sub-area B) Category Basis of classification Classification results I T-N, T-P, winter DIN and winter DIP were at high levels with no decreasing trend HN Current status was relatively high and there was no increasing or decreasing trend II Chlorophyll-a of field and remote sensing were at high levels with no decreasing trend HN Current status was relatively high and there was no increasing or decreasing trend III COD was at high levels with no decreasing trend HN Current status was relatively high and there was no increasing or decreasing trend IV Current status of all parameters were classified as low status and all parameters had no significant increasing trend LN Current status was relatively low and there was no increasing or decreasing trend Sub-area B was identified as having relatively high levels of eutrophication and direct/indirect eutrophication impacts. 18

19 5. Verification of results Verification of sub-area boundaries Seasonal averaged Chlorophyll-a concentration in Spring and Summer were compared to verify the subarea boundaries. Purple pixels in the left image shows areas where chlorophyll-a concentration was higher in summer season (Apr to Jul) than in spring season (Feb to Apr). Right image shows the sub-areas of the case study. 19

20 6. Conclusion and recommendation Re-examination of the Draft Procedures The identification criteria of assessment data should be re-examined to improve its reliability with more appropriate scientific approaches. Further utilization of remote sensing techniques Assessment and analysis techniques of remote sensing must also be improved in accordance with its technological development. Improvement of the Draft Procedures The validity and effectiveness of the Draft Procedures must be examined by collecting opinions from experts of various fields. 20