M. Shah Alam Khan Professor Institute of Water and Flood Management,

1. WFM 6209 : Interdisciplinary Field Research Methodology in Water Management Hydro-ecological Investigation M. Shah Alam Khan Professor Institute of Water and Flood Management, Bangladesh University of Engineering and Technology

2. Hydro-ecological InvestigationObjectives • Learn application of hydro-ecological investigation techniques and analysis methods that may be required for interdisciplinary field research. • Learn how to interpret the results of analysis in terms of the biophysical environment.

3. Hydro-ecological Investigation • Water quantity measurement and analysis Physico-chemical analysis of water and soil Ecological Assessment Agro-ecological Assessment RS and GIS Applications

4. Environmental Descriptors • Physical-Chemical Environment • Biological Environment • Socioeconomic Environment • Political Environment • Cultural Environment • … …

5. Environmental Descriptors • Physical-Chemical Environment

6. Physical-Chemical Environment Water quality - Physical parameters (suspended solids, turbidity, color, taste and odor, temperature, etc.) - Chemical parameters (pH, alkalinity, hardness, fluoride, metals, organics, nutrients, etc.) - Biological parameters (pathogens, pathogen indicators) • Surface water resources (flow, volume, depth, in-stream storage, etc.) • Groundwater resources (levels, recharge, quantity and quality) • Soils • Land type, land use • Geology • Topography • Agriculture • Climatology (precipitation, evapotranspiration, etc.) • Air quality • Noise pollution

7. Hydro-ecological Investigation : Kaliakoir Measurement / Secondary data • Water Quantity: - Flow rate in khals, river - Discharge (flow rate) from industries - GW withdrawn by industries - GW levels - WL in beels • Water Quality: - Color, Solids, Temperature, pH, Hardness, Metals, DO, BOD, COD, Nutrients • Ecology: - Fish: Population (catch), Composition (diversity) - Other flora/fauna • RS and GIS Applications: - Land type, Land use, Drainage network, Resource maps

8. Hydro-ecological Investigation : Kaliakoir Analysis • Impact of GW withdrawal by industries • Pollutant mass balance: impact of industrial discharge • Historical change in WQ (surface and groundwater) • Historical change in fish catch and diversity • Historical change in land use, water bodies

9. Hydrologic Cycle • Interference at one stage can cause serious repercussions at some other stage of hydrologic cycle • It is important to understand the relationship among the components at different stages of the cycle

10. Hydrologic CycleThe Hydrologic Cycle and Water Quality Water in nature is most nearly pure in its evaporation state. Condensation of water around particles acquires impurities. Additional impurities are acquired as the liquid water travels further through the hydrologic cycle. Human activities contribute further impurities through: - industrial and domestic wastes - agricultural chemicals. Impurities in water may be in both suspended and dissolved forms. - Suspended materials are larger than molecular size. - Dissolved materials consist of molecules or ions that are held by the molecular structure of water. - Colloids (10-3 to 10-6 mm) are very small suspended particles, but often exhibit many characteristics of the dissolved substances.

11. Water Pollution Presence of impurities in water in such quantity and of such nature as to impair the use of water for a stated purpose. ‘Pollution’ is a relative term – depends on intended use. ‘Water Quality Parameters’ qualitatively reflect the impact of impurities on selected water uses. Analytical procedures quantitatively measure the parameters that represent the physical, chemical and biological characteristics of water.

12. Water Quality: Measurement and Analysis Chemical Parameters: 1. pH 2. Total Dissolved Solids 3. Alkalinity 4. Salinity 5. Hardness 6. Fluoride 7. Metals 8. Organics (DO, BOD) 9. COD 10. Nutrients Physical Parameters: 1. Color 2. Taste and Odor 3. Solids (Suspended, Total) 4. Turbidity 5. Temperature • Source, Impact and Measurement of each parameter • Consult Standards and Guidelines for specific use

13. Water Quality: Measurement and Analysis Water Quality: Measurement and Analysis Physical Parameters Color Sources: • Domestic and industrial wastes, natural decay of organic materials. • Organic debris such as leaves, weeds or wood. • Industrial wastes from textile and dyeing operations, pulp and paper production, food processing, chemical production, and mining, refining and slaughterhouse operations. • Iron-oxides cause reddish color, and manganese oxides cause brown or brackish water. • Impacts: • Color affects acceptability of water as both domestic and industrial product. • Colored water is not aesthetically acceptable to the general public. • Highly colored water is unsuitable for laundering, dyeing, papermaking, beverage manufacturing, dairy production and other food processing, and textile and plastic production.

14. Water Quality: Measurement and Analysis Physical Parameters Color Measurement: • Often measured by comparison with standardized colored materials. • Color-comparison tubes containing a series of standards (different colors) may be used for direct comparison with the water sample. • Results are expressed as True Color Units (TCU) where one unit is equivalent to the color produced by 1 mg/L of platinum in the form of chlorplatinate ions. • Special spectrophotometric techniques are normally used for colored water originating from industrial waste effluents. • Calibrated colored disks are used in field work.

15. Water Quality: Measurement and Analysis Physical Parameters Taste and Odor Sources: • Many natural or artificial substances impart taste and odor including: - Minerals, metals and salts from the soil - End products from biological reactions - Constituents of wastewater • Inorganic substances are more likely to produce tastes unaccompanied by odors. • Organic materials are likely to produce both taste and odor. • Alkaline materials impart bitter taste; metallic salts may give a salty or bitter taste. • Petroleum-based products are the primary taste- and odor-producing organic chemicals. • Biological decomposition of organics may also result in taste- and odor-producing liquids and gases. (e.g. ‘rotten egg’ taste and odor of sulfur). • Certain species of algae secrete taste- and odor-producing oily substance. • Sometimes the combination of two or more substances, neither of which would individually produce taste or odor, may cause taste and odor problems.

16. Water Quality: Measurement and Analysis Physical Parameters Taste and Odor Impacts: • Displeasing to the consumers for obvious reasons. • Some odor-producing organic substances are found to be carcinogenic. Measurement: Quantitative tests sometimes employ human senses of taste and smell. The Threshold Odor Number (TON) test uses varying volumes of the sample diluted to 200mL with distilled water. 5 to 10 people determine the mixture in which the smell is just barely detectable. The TON is given by, where A = the volume of odorous water (mL), and B = the volume (mL) of odor-free water required to produce a 200-mL mixture.

17. Water Quality: Measurement and Analysis Physical Parameters Solids Sources: • May consist of inorganic or organic particles, or immiscible liquids: - Inorganic solids: clay, silt or other soil constituents; - Organic solids: plant fibers and biological solids (algal cells, bacteria, etc.); - Immiscible liquids: oils and greases. • Common constituents of surface waters. • Often result from erosive action of water over surfaces. • Very rarely found in groundwater because of the natural filtering capacity of soil. • May also result from human use: - Domestic wastewater usually contains large quantities of organic solids; - Industrial wastewater contains both inorganic and organic solids. Impacts: • Aesthetically displeasing; • Provides adsorption sites (surfaces) for chemical and biological agents; • Biological degradation of organic solids may produce objectionable by-products; • Biologically active solids may include disease-causing organisms and toxin-producing algae. Measurement: • Total Solids Test • Suspended Solids Test

18. Water Quality: Measurement and Analysis Physical Parameters Solids Measurement: • Total Solids Test - measures all solids (suspended and dissolved, inorganic and organic): - Water sample is heated to a temperature slightly above boiling (104oC) [drives off liquids and the water adsorbed to the particle surfaces; a temperature of about 180oC is required to evaporate the occluded water]; - The residue is weighed and expressed as milligrams per liter (mg/L) [‘dry-mass’ weight of residue (in mg) per liter volume of sample]. • Suspended Solids Test - measures the mass of residue retained on a filter (paper). - The water sample is filtered, and the filter and residue is dried to a constant weight at 104oC (+/- 1oC). - The difference between weights of the filter before and after filtration gives the weight of residue (suspended solids). - Residue (dry-mass) is expressed as mg/L.

19. Water Quality: Measurement and Analysis Physical Parameters Solids The Dissolved Solids passing through the filters is the difference between the total-solids and suspended-solids contents of the sample. Figure: Filtration apparatus.

20. Water Quality: Measurement and Analysis Physical Parameters Solids Notes: 1. Some solids (e.g. colloids) may pass through the filter and add to the dissolved-solids contents (filterable residues) while some dissolved solids may adsorb to the filter material and add to the suspended-solids content (nonfilterable residues). [extent depends on the size and nature of the solids, and the pore opening and nature of the filter material]. 2. Organic content of both total and suspended solids can be removed by firing (burning in oven) the residues at 600oC for 1 hour. [organic fraction converts into carbon dioxide, water vapor and other gases; a filter made of glass fiber or other high-temperature resistant material is used]. Use: An important parameter of wastewater: • to indicate the quality of influent and effluent. • to monitor treatment processes.

21. Water Quality: Measurement and Analysis Physical Parameters Solids

22. Water Quality: Measurement and Analysis Physical Parameters Turbidity - A measure of the extent to which light is either absorbed or scattered by suspended materials in water. - Turbidity tests are commonly performed on natural water bodies and potable (drinkable) water supplies. - Turbidity does not directly quantify the suspended solids. • Sources: • Erosion of colloidal materials such as clay, silt and metal oxides from the soil. • Vegetable fibers and microorganisms. • Domestic and industrial wastewaters (soaps, detergents and emulsifying agents produce stable colloids). • Discharges of wastewaters may increase the turbidity of natural water bodies. • Impacts: • Aesthetically displeasing opaqueness (‘milky’ coloration). • Turbidity-producing colloidal materials provide adsorption sites for taste- and odor-producing chemicals, and harmful organisms. • Disinfection of turbid waters is difficult because of the adsorptive characteristics of the colloids and since the solids may partially shield the organisms. • Turbid waters interfere with light penetration and photosynthetic reactions in streams and lakes. • Turbidity-causing fine particles may deposit on porous streambed and adversely affect the flora and fauna. • Suspended materials absorb heat from sunlight and raise the water temperature.

23. Water Quality: Measurement and Analysis Physical Parameters Turbidity Measurement:

24. Water Quality: Measurement and Analysis Physical Parameters Temperature - Influences to a large extent the biological species and their activity rates in water. - Affects most chemical reactions and solubility of gases in natural water systems. Sources: • The natural-water temperature responds to the ambient (surrounding) temperature. Generally, shallow water bodies are more affected by ambient temperature. • The warm or heated water discharged from many industries may dramatically (but locally) elevate the temperature of receiving streams. Impacts: • Cooler water usually allows wider diversity of biological species. • Accelerated algal growth occurs in warm water, and may cause problems by oil secretion, thick ‘algal mat’ (cells joined together) and decay products of the dead algae cells. • Higher-order species, e.g. fish, are drastically affected by change in temperature, and by change in dissolved oxygen (a function of temperature).

25. Water Quality: Measurement and Analysis Physical Parameters Temperature Impacts: • More chemical reactions involving dissolution of solids are accelerated by increased temperatures. • Increase in temperature affects physical properties of water including: Viscosity (decrease), and density (maxm at 4oC). • Temperature and density affect the growth and stratification of planktonic microorganisms in natural water systems. Measurement: By thermometers, thermocouples and transducers.

26. pH Water Quality: Measurement and Analysis Chemical Parameters pH = - log [H+] (negative logarithm of hydrogen ion concentration) pH = 7 => ‘neutral’ pH < 7 => ‘acidic’ pH > 7 => ‘basic/alkaline’ Impacts: • If pH < 5.5, the water may be too acidic for fish to survive in, while water with a pH > 8.6 may be too basic. • A change in pH can also affect aquatic life indirectly by altering other aspects of water chemistry. For example, low pH levels can increase the solubility of certain heavy metals.

27. Water Quality: Measurement and Analysis Chemical Parameters Alkalinity The quantity of ions in water that will react to neutralize hydrogen ions. Alkalinity is thus a measure of the ability of water to neutralize acids. Sources: • Commonly found in natural water systems: carbonate (CO32-), bicarbonate (HCO3-), hydroxide (OH-), silicate (HSiO3-), bromate (H2BO3-), phosphates (HPO42-, H2PO4-), sulfide (HS-), and ammonia (NH30). These result from dissolution of mineral substances in soil and atmosphere. • Phosphates may also originate from detergents in wastewaters and from fertilizers and insecticides from agricultural land. Hydrogen sulfide and ammonia may be produced from microbial decomposition of organic material. • Most common constituents of alkalinity: CO32-, HCO3-, and OH-. In addition to their mineral origin these constituents may originate from carbon dioxide (CO2) and microbial decomposition of organic material. • The relative quantities of alkalinity species are pH dependent. • Figure shows variation in concentrations of alkalinity species with pH.

28. Water Quality: Measurement and Analysis Chemical Parameters Alkalinity

29. Water Quality: Measurement and Analysis Chemical Parameters Alkalinity Impacts: • In large quantities, alkalinity imparts a bitter taste to water. • A major problem with alkaline water is the reaction that may occur between alkalinity species and certain cations. Resultant precipitates may damage pipes and other appurtenances. Measurement : • Alkalinity is measured by titrating the water with an acid and determining the hydrogen equivalent. Alkalinity is usually expressed as mg/L of CaCO3. If 0.02 N H2SO4 (0.02 ‘Normal’ sulfuric acid; ‘Normal’ indicates strength of acid) is used for titration, then 1 mL of the acid will neutralize 1 mg of alkalinity as CaCO3. • The volumes of acid required to reach the endpoints of titration (pH = 8.3 and pH = 4.5) determine the different species of alkalinity present. Endpoints are indicated by change of color of certain chemicals called indicators that are added before titration. Use: • Alkalinity indicates the buffering capacity (acid neutralizing capacity) of natural waters. • Also used as process control variable in water and wastewater treatment.

30. Water Quality: Measurement and Analysis Chemical Parameters Hardness • Concentration of multivalent metallic cations in solution. In supersaturated condition, the hardness cations react with anions to form a solid precipitate. • Hardness can be classified as carbonatehardness and noncarbonatehardness depending on the anions they are associated with. Hardness equivalent to the alkalinity is called carbonate hardness. Any remaining hardness is called noncarbonate hardness. Carbonate hardness is sensitive to heat and precipitates readily at high temperatures. Sources: • Calcium and magnesium constitute almost all hardness in natural waters. • Others include iron and manganese in their reduced forms (Fe2+, Mn2+), strontium (Sr2+), and aluminum (Al3+). Impacts: Sodium-based soaps react with the hardness cations to form a precipitate, thereby losing their surfactant properties. Soap consumption by hard water incurs economic loss to the water user. Precipitates formed by hardness and soap adhere to appurtenance surfaces and may stain clothing and utensils. Use of hard water may result in rough, uncomfortable skin. Certain soaps do not react with hardness.

31. Water Quality: Measurement and Analysis Chemical Parameters Flouride • Generally found in surface waters; rarely found in groundwater. • Toxic to human and other animals in large quantities; small quantities may be beneficial: approx. 1 mg/L in drinking water may help prevent dental cavity, and form decay resistant teeth. • Excessive fluoride in drinking water causes discoloration of teeth (mottling) and bone formation abnormalities.

32. Water Quality: Measurement and Analysis Chemical Parameters Metals • All metals are soluble to some extent in water. • Metals that are harmful in relatively small amounts are considered toxic. • Metals in natural waters originate from dissolution of natural deposits, and discharges of domestic, industrial or agricultural wastewaters. • Measurement usually made by atomic absorption spectrophotometer (AAS).

33. Water Quality: Measurement and Analysis Chemical Parameters Metals Nontoxic Metals: • Commonly found in water; include sodium, iron, manganese, aluminum, copper and zinc. • Sodium is the most common nontoxic metal and highly reactive to other elements; excessive concentrations of sodium salts impart a bitter taste, and are hazardous to cardiac and kidney patients; also corrosive to metal surfaces and toxic to plants. • Iron and manganese frequently occur together in natural waters and present no health hazard. May produce color problems and bacterial growth causing taste and odor. • Significant quantities of iron are usually found in systems devoid of oxygen such as groundwater and bottom layers of stratified lakes. • Copper and zinc, if both present, may be toxic to many biological species.

34. Water Quality: Measurement and Analysis Chemical Parameters Metals Toxic Metals: • Harmful to human and other organisms in small quantities. • Toxic metals that may be dissolved in water include arsenic, barium, cadmium, chromium, lead, mercury and silver. Arsenic, cadmium, lead and mercury are particularly hazardous. • These metals are concentrated by the food chain. • Toxic metals usually originate from natural, industrial, or agricultural sources.

35. Water Quality: Measurement and Analysis Chemical Parameters Organics Many organics in natural water systems originate from natural sources and are soluble in water. May consist of the decay products of organic solids, or result from wastewater and agricultural discharges. Harmful to human and other organisms in small quantities. Biodegradable Organics: • Organics that are used up by microorganisms for food; usually consist of starches, fats, proteins, alcohols, aldehydes and esters. • Microbial decomposition of dissolved organics normally takes place accompanied by oxidation (addition of oxygen or reduction of hydrogen), or by reduction (addition of hydrogen or reduction of oxygen). • The decomposition may occur in aerobic (oxygen-present) or anaerobic(oxygen-absent) environment. • Anaerobic decomposition results in unstable and objectionable end products. • When oxygen utilization occurs more rapidly than oxygen is replenished, anaerobic conditions occur that severely affect the ecology of the system. • The amount of oxygen consumed during microbial utilization of organics is called Biochemical Oxygen Demand (BOD).

36. Water Quality: Measurement and Analysis Chemical Parameters Organics BOD is measured by determining the oxygen consumed from a sample placed in an air-tight container and kept in a controlled environment for a specified period of time. In the standard test, a 300-mL BOD bottle is used and the sample is incubated at 20oC for 5 (sometimes 7) days. Light is excluded from the incubator to prevent algal growth. The saturation concentration of oxygen in water at 20oC is approx. 9 mg/L. Dilution or seeding of the sample may be required depending on the anticipated BOD of the sample. The BOD of a diluted sample is calculated by, where DOi and DOf are the initial and final dissolved oxygen concentrations, and P is the decimal fraction of the sample in the BOD bottle. P = 1.0 for no dilution. Presence of toxic materials in water will invalidate the BOD results.

37. Water Quality: Measurement and Analysis Chemical Parameters Organics Table 2.5 shows ranges of BOD covered by various dilutions, assuming an initial dissolved-oxygen concentration of 9 mg/L, and for a 2 to 7 mg/L consumption of oxygen.

38. Water Quality: Measurement and Analysis Chemical Parameters Organics

39. Water Quality: Measurement and Analysis Chemical Parameters Organics The BOD for any time period can be determined mathematically by, where Lt = the oxygen equivalent of the organics at time t, Lo = oxygen equivalent of the organics at time zero, and k = a reaction constant. Units of L and k are mg/L and day-1, respectively. Figure shows the variation of BOD and oxygen-equivalent of organics with time.

40. Water Quality: Measurement and Analysis Chemical Parameters Organics Non-Biodegradable Organics: • Some organic materials (tannic and lignic acids, cellulose, phenols, etc.) are resistant to biological degradation. • Benzenes and molecules having strong bonds are nonbiodegradable. • Many insecticides and herbicides are nonbiodegradable, and may be extremely harmful to human and other species. • Nonbiodegradable organics may be measured by the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) analyses. (BOD must be subtracted)

41. Water Quality: Measurement and Analysis Chemical Parameters Nutrients • Nutrients are elements essential to the growth and reproduction of plants and animals. • A wide variety of minerals and trace element may be classified as nutrients. • Carbon, nitrogen and phosphorus are required in most abundance by the aquatic species.

42. Water Quality: Measurement and Analysis Biological Parameters Pathogens Communicable diseases are caused by bacteria, viruses, protozoa or helminths (parasitic worms). Bacterial diseases include typhoid, paratyphoid, salmonellosis, shigellosis, bacillary dysentery, and cholera. Viral diseases include hepatitis, poliomyelitis, and some varieties of gastroenteritis. Protozoa such as Giardia and Cryptosporidium may produce gastroenteritis. Certain fungi such as Aspergillus also produce diseases in human bodies.

43. Water Quality: Measurement and Analysis Biological Parameters Pathogen Indicators Testing for all possible microorganisms is infeasible or very expensive. Possibility of water contamination is usually assessed by determining the number of coliform bacteria. Escherachia coli is exerted up to 4X1010 organisms per person per day. Presence of coliform is not a proof that water is contaminated; but absence indicates that the water is free of pathogens.

44. Air Pollution Impacts on Water Quality • Major pollutants of air: • Dust particles • Industrial emission • Vehicular exhaust • CFCs (chlorofluorocarbons) • Air pollutants either settle down, or are washed down by rainfall, eventually affecting the water quality.

45. End of Lecture