analysis of water chemistry

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Outline. Water Chemistry BackgroundChemistry in Urban StreamsMethods2003 ResultsComparison to 2002Conclusions. Outline. Water Chemistry BackgroundChemistry in Urban StreamsMethods2003 ResultsComparison to 2002Conclusions. Temperature. Most aquatic organisms are cold-blooded and have an ideal temperature range, specific to the organism:Diatoms 15-25 degrees CGreen algae 25-35 degrees CBlue greens 30-40 degrees CSalmonids

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1. Analysis of Water Chemistry Urban Stream Restoration Project

3. Outline Water Chemistry Background Chemistry in Urban Streams Methods 2003 Results Comparison to 2002 Conclusions

4. Temperature Most aquatic organisms are cold-blooded and have an ideal temperature range, specific to the organism: Diatoms 15-25 degrees C Green algae 25-35 degrees C Blue greens 30-40 degrees C Salmonids – cold water fish

5. Temperature, continued Affects development of invertebrates, metabolism of organisms Affects dissolved oxygen (warm water holds less oxygen) Warm water makes some substances more toxic (cyanide, phenol, xylene, zinc) and, if combined with low DO, they become even more toxic

6. Dissolved Oxygen Oxygen that is dissolved in water DO increases with cooler water and mixing of water through riffles, storms, wind Nutrient loading can lead to algal blooms which result in decreased DO 4-5 ppm DO is the minimum that will support large, diverse fish populations. Ideal DO is 9 ppm. Below 3 ppm, all fish die.

7. Dissolved Oxygen, continued Dissolved oxygen can also be expressed as % saturation 80-124% = excellent 60-79% = ok < 60% = poor

8. Conductivity Measures the ability of water to carry an electric current Measures the ions such as Na+, Cl- in the water Differences in conductivity are usually due to the concentration of charged ions in solution (and ionic composition, temp.) Reported as microsiemens per cm

9. pH pH measures the degree of acidity or alkalinity of the water (each number is a 10-fold difference) 0-6 = acid; 7 = neutral; 8-14 = base Ideal for fish = 6.5 –8.2 Ideal for algae = 7.5 – 8.4 Acid waters make toxic chemicals (Al, Pb, Hg) more toxic than normal, and alter trophic structure (few plants, algae)

10. Turbidity Measures the cloudiness of the water Turbidity caused by plankton, chemicals, silt, etc. Most common causes of excess turbidity are plankton and soil erosion (due to logging, mining, farming, construction)

11. Turbidity, continued Excess Turbidity can be a problem: Light can’t penetrate through the water – photosynthesis may be reduced or even stop – algae can die Turbidity can clog gills of fish and shellfish –can be fatal Fish cannot see to find food, but can hide better from predators

12. Phosphorus (Reactive) Is necessary for plant and animal growth Natural source = phosphate-containing rocks Anthropogenic source = fertilizer and pesticide runoff from farming Can stimulate algal growth/bloom

13. Nitrates Formed by the process of nitrification (addition of O2 to NH3 by bacteria) Used by plants and algae Is mildly toxic, fatal at high doses Large amounts (leaking sewer pipes, fertilizer runoff, etc.) can lead to algal blooms, which can alter community structure, trophic interactions and DO regimes) Below 90 mg/L seems to have no effect on warm water fish, but cold water fish are sensitive

14. Alkalinity A measure of the substances in water that can neutralize acid and resist changes in pH Natural source = rocks Ideal water for fish and aquatic organisms has a total alkalinity of 100-120 mg/L Groundwater has higher alkalinity than surface water

15. Hardness The amount of Calcium and Magnesium in the water (the two minerals mostly responsible) Natural source = rocks Limestone = hard water, granite = not hard water

16. Hardness, continued Soft water can be a problem: in soft water, heavy metals are more poisonous, some chemicals are more toxic, drinking soft water over long periods can increase chance of heart attack 0 – 60 = soft water 61-120 = moderately hard water 121-180 = hard water 181+ = very hard water Hardness and alkalinity are related

17. Outline Water Chemistry Background Chemistry in Urban Streams Methods 2003 Results Comparison to 2002 Conclusions

18. Physical Effects of Urbanization Related to Water Chemistry Riparian Vegetation Removal Decreased Groundwater Recharge Heat Island Effect Increased Surface Runoff / Impervious Surfaces Leaky Storm-water / Sewage Pipes Point Source Pollution

19. Trends in Water Chemistry Temperature increases Nitrate increases Phosphorus increases Conductivity increases (Increased ion concentration) O2 demand increases

20. Outline Water Chemistry Background Chemistry in Urban Streams Methods 2003 Results Comparison to 2002 Conclusions

21. Field Measurements Dissolved Oxygen Temperature Conductivity pH

22. Water Collection For Laboratory Analysis Grab Samples Three replicates (from multiple samples) Measured within 24 hours (few exceptions)

23. Laboratory Analysis Nitrate Reactive Phosphorus Alkalinity Hardness Turbidity

24. Outline Chemistry in Urban Streams Water Chemistry Measurements and Theory Methods 2003 Results Comparison to 2002 Conclusions

25. Field Measurements 2003

26. Turbidity All values for 2003 <5 jtu For 2002, all but one sampling date <5 jtu The one date for 2002 >5 was during a storm event

27. Reactive Phosphorus 2003

28. Nitrate 2003

29. Alkalinity 2003

30. Hardness 2003

31. Outline Chemistry in Urban Streams Water Chemistry Measurements and Theory Methods 2003 Results Comparison to 2002 Conclusions

32. Field Measurement PB

33. Field Measurement For SAL

34. Paint Branch

35. Stewart April Lane

36. Outline Chemistry in Urban Streams Water Chemistry Measurements and Theory Methods 2003 Results Comparison to 2002 Conclusions

37. Between Site Differences Land use – increased runoff cause increased input of particular constituents Natural site variation – Substrate type Between Years Increased snow caused more runoff increased use of road-salt Drought (temperature, DO)

38. “. . . Rivers and the inhabitants of the watery element were made for wise men to contemplate, and fools to pass by without consideration, . . . for you may note, that the waters are Nature’s storehouse, in which she locks up her wonders.” Izaak Walton (from Ward, 1992)

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