Mod10 11 part1
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This document provides an overview of techniques for assessing water quality in streams. It discusses parameters such as dissolved oxygen, suspended sediments, turbidity, conductivity, pH and temperature. Methods are described for measuring these parameters in the field using probes and other tools. The document also covers topics like sediment embeddedness and how factors like development and erosion can impact water quality. Overall it serves as a guide for monitoring common indicators of stream water quality.
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Mod10 11 part1
- 1. Module 10/11 Stream Surveys Stream Surveys – February 2004 Part 1 – Water Quality Assessment
- 2. Objectives Students will be able to: · describe techniques used to determine dissolved oxygen. · list factors that influence high turbidity and suspended solids in streams. · explain methods used to determine total suspended solids. · evaluate the relationship between total suspended solids and turbidity. · identify methods used to determine water clarity in streams. · assess habitat degradation by determining the degree of sediment embeddedness in a stream. · analyze the impact of dissolved salts, pH and temperature on streams. · describe accepted sampling methods used in stream surveys. Developed by: Updated: U5-m21a-s2
- 3. Stream assessments ·Water quality · Habitat · Hydrologic · Biological · Watershed Developed by: Updated: U5-m21a-s3
- 4. Water quality parameters Developed by: Updated: U5-m21a-s4
- 5. Water Quality Parameters · Dissolved oxygen · Suspended sediments (TSS) and turbidity · Specific conductivity (EC) · alkalinity · pH · Temperature · Major ions ·All of these parameters are presented in greater detail in Module 9 – Lake surveys Developed by: Updated: U5-m21a-s5
- 6. Dissolved Oxygen Developed by: Updated: U5-m21a-s6
- 7. DO – importance and reporting · Oxygen is produced during photosynthesis and consumed during respiration and decomposition. · Generally < 3 mg/L is stressful to aquatic life. · Units of measurement are: · Concentration: mg/L = ppm; concentrations range 0.0 to 20 mg/L · % saturation – used to determine if water is fully saturated with oxygen at a particular temperature Developed by: Updated: U5-m21a-s7
- 8. DO – techniques · Probe types and measurement techniques: · Winkler titration · Amperometric (polarographic) method, most commonly used http://www.lumcon.edu/education/StudentDatabase/gallery.asp Developed by: Updated: U5-m21a-s8
- 9. DO – probes · Most common sensor is the temperature compensated polarographic membrane-type (amperometric) · Temperature sensitive (but virtually all are compensated). · The probes actually consume O2 as they work so measurements require moving water using either a built-in stirrer (typical in multiparameter sondes and BOD probes) or “hand jiggling” during the measurement. · in situ sensors are prone to fouling by algal/bacterial slimes and by silt in streams. Developed by: Updated: U5-m21a-s9
- 10. DO probes and meters · The WOW units use either Hydrolab or YSI multiprobe datasounds, but there are many others Developed by: Updated: U5-m21a-s10
- 11. Sedimentation/siltation · Excessive sedimentation in streams and rivers is considered to be a major cause of surface water pollution in the U.S. by the USEPA Developed by: Updated: U5-m21a-s11
- 12. Measures of sedimentation · Suspended sediments · Turbidity · Embededdness Developed by: Updated: U5-m21a-s12
- 13. High turbidity and suspended solids · Caused by many factors including: · soil erosion · domestic and industrial wastewater discharge · urban runoff · flooding · algal growth due to nutrient enrichment · dredging operations · channelization · removal of riparian vegetation and other stream bank disturbances Developed by: Updated: U5-m21a-s13
- 14. Total suspended solids and turbidity · Both are indicators of the amount of solids suspended in the water · Mineral (e.g., soil particles) · Organic (e.g., algae, detritus) · TSS measures the actual weight of material per volume of water (mg/L) · Turbidity measures the amount of light scattered · Therefore, TSS allows the determination of an actual concentration or quantity of material while turbidity does not Developed by: Updated: U5-m21a-s14
- 15. Measuring TSS 1. Filter a known amount of water through a pre-washed, pre-dried at 103-105 oC, pre-weighed (~ + 0.5 mg) filter 2. Rinse, dry and reweigh to calculate TSS in mg/L (ppm) 3. Save filters for other analyses such as volatile suspended solids (VSS) that estimate organic matter Developed by: Updated: U5-m21a-s15
- 16. Total suspended solids - method What type of filter to use? Developed by: Updated: U5-m21a-s16
- 17. Total suspended solids Calculate TSS by using the equation below TSS (mg/L) = ([A-B]*1000)/C Developed by: Updated: U5-m21a-s17 where A = final dried weight of the filter (in milligrams = mg) B = Initial weight of the filter (in milligrams = mg) C = Volume of water filtered (in Liters)
- 18. TSS · Range of results and what the results mean · Example: Suspended solids concentrations at Slate Creek WA average 150.8 mg/l with a range of 50 to 327 mg/l. It is generally desired to maintain total suspended solid concentrations below 100 mg/l. Developed by: Updated: U5-m21a-s18
- 19. Measuring turbidity ·Turbidity measures the scattering effect suspended particles have on light ·inorganics like clay and silt ·organic material, both fine and colored ·plankton and other microscopic organisms ·Transparency or turbidity tubes Even small amounts of wave action can erode exposed lakeshore sediments, in this case a minepit lake from northeastern Minnesota. Guess the mineral mined here. Developed by: Updated: U5-m21a-s19
- 20. Turbidity · Field turbidity measurements are made with · Turbidimeters (bench meter for discrete samples) · Submersible turbidity sensors (Note - USGS currently considers this a qualitative method) Hydrolab turbidity probe Developed by: Updated: U5-m21a-s20
- 21. Turbidity - Nephelometric optics · Nephelometric turbidity estimated by the scattering effect suspended particles have on light · Detector is at 90o from the light source Developed by: Updated: U5-m21a-s21
- 22. Turbidity – units and reporting • Nephelometric Turbidity Units (NTU) standards are formazin or other certified material • JTU’s are from an “older” technology in which a candle flame was viewed through a tube of water 1 NTU = 1 JTU (Jackson Turbidity Unit) Developed by: Updated: U5-m21a-s22
- 23. Turbidity - standards · Top - a range of formazin standards · Bottom –the same NTU range using a clay suspension Developed by: Updated: U5-m21a-s23
- 24. Turbidity · Range of results and what the results mean · Ex: Salmon Creek Watershed (OR/WA border) TMDL for turbidity is: "Turbidity shall not exceed 5 NTU over background turbidity when the background turbidity is 50 NTU or less. Or more than a 10% increase in turbidity when the background turbidity is > 50 NTU”. Developed by: Updated: U5-m21a-s24
- 25. How do turbidity and TSS relate? Developed by: Updated: U5-m21a-s25
- 26. TSS vs Turbidity relationship Developed by: Updated: U5-m21a-s26 TSS Turbidity Yearly average Summer range (May-Oct) Winter range (Nov-Apr) Cedar River 3.6 1.1 0.6-5.0 0.4-1.2 3.5-6.2 1.0-2.0 Newaukum Ck 5.7 2.4 1.6-5.1 0.7-1.5 7.5-8.8 3.1-4.0 Springbrook Ck 19.8 22.0 8.0-26.0 13.0-44.0 6.7-44.0 13.0-35.0
- 27. Water clarity – transparency tubes Developed by: Updated: U5-m21a-s27
- 28. Water clarity – transparency tubes • Used in streams, ponds, wetlands, and some coastal zones · Analogous to secchi depth in lakes: a measure of the dissolved and particulate material in the water Developed by: Updated: U5-m21a-s28
- 29. Water clarity – transparency tubes · Useful for shallow water or fast moving streams bodies where a secchi would still be visible on the bottom • It is a good measure of turbidity and suspended sediment (TSS) • Used in many volunteer stream monitoring programs Developed by: Updated: U5-m21a-s29
- 30. Horizontal secchi · Newer method – all-black disk viewed horizontally Developed by: Updated: U5-m21a-s30
- 31. Embeddedness · Measure of fine sediment deposition in the interstitial spaces between rocks · High embeddedness values indicate habitat degradation · Visual assessment used to estimate the degree of embeddedness Developed by: Updated: U5-m21a-s31
- 32. Embeddedness – cont. · The stream-bottom sediments to the top right provide spaces for fish to lay eggs and for invertebrates to live and hide. · Excess erosion has deposited fine grained sediments on the stream bottom to the bottom right. There are no spaces available for fish spawning or for invertebrate habitat. Developed by: Updated: U5-m21a-s32
- 33. Embededdness – visual assessment · Embeddedness: General guidelines · 0% = no fine sediments even at base of top layer of gravel/cobble · 25% = rocks are half surrounded by sediment · 50% = rocks are completely surrounded by sediment but their tops are clean · 75% = rocks are completely surrounded by sediment and half covered · 100% = rocks are completely covered by sediment Developed by: Updated: U5-m21a-s33
- 34. Specific electrical conductivity = EC25 Developed by: Updated: U5-m21a-s34
- 35. EC25 - importance · Cheap, easy way to characterize the total dissolved salt concentration of a water sample · For tracing water masses and defining mixing zones · Groundwater plumes · Stream flowing into another stream or into a lake or reservoir Developed by: Updated: U5-m21a-s35
- 36. EC25 – units and reporting Principle of measurement • A small voltage is applied between 2 parallel metal rod shaped electrodes, usually 1 cm apart • Measured current flow is proportional to the dissolved ion content of the water • If the sensor is temperature compensated to 25oC, EC is called “specific” EC (EC25) Developed by: Updated: U5-m21a-s36
- 37. EC25 - units · What in the world are microSiemens per centimeter (μS/cm)? • Units for EC and EC25 are mS/cm or μS/cm @25oC. The WOW site reports it as EC @25oC (in μS/cm). • Usually report to 2 or 3 significant figures (to + ~ 1- 5 μS/cm) ·More details can be found in Module 9 Developed by: Updated: U5-m21a-s37
- 38. Developed by: Updated: U5-m21a-s38 EC25 · EC25 values in streams reflect primarily a combination of watershed sources of salts and the hydrology of the system · wastewater from sewage treatment plants and industrial discharge · wastewater from on-site wastewater treatment and dispersal systems (septic systems and drainfields) · urban runoff · agricultural runoff · acid mine drainage · atmospheric inputs
- 39. Snowmelt runoff example Developed by: Updated: U5-m21a-s39
- 40. Developed by: Updated: U5-m21a-s40 pH Image courtesy of USGS at http://www.usgs.gov/
- 41. pH – importance in aquatic systems · The pH of a sample of water is a measure of the concentration of hydrogen ions. · pH determines the solubility and biological availability of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.). Developed by: Updated: U5-m21a-s41
- 42. pH - reporting · pH can be measured electrometrically or colorimetrically (pH paper) BUT ONLY the former technique is approved by the EPA and USGS for natural waters. · The electrometric method uses a hydrogen ion electrode. · pH meters require extensive care in handling and operation. · Report to the nearest 0.1 standard pH unit Developed by: Updated: U5-m21a-s42
- 43. pH – probes · Field probe types: · Combination probes (e.g.YSI) · Less expensive; more rugged design · Less precise · Shorter life because reference solution cannot be replenished · Separate reading and reference electrodes (e.g., Hydrolab) · Costs more ·More precise; faster response time · Allows user maintenance; Teflon junction and electrolyte can be replaced Developed by: Updated: U5-m21a-s43
- 44. pH – probes · Or, alternatively, a bench or hand-held meter and probe can be used in a fresh subsample if you don’t have a field meter with a pH probe. Developed by: Updated: U5-m21a-s44
- 45. Temperature Developed by: Updated: U5-m21a-s45
- 46. Temperature importance · Temperature affects: · the oxygen content of the water (oxygen levels become lower as temperature increases) · the rate of photosynthesis by aquatic plants · the metabolic rates of aquatic organisms · the sensitivity of organisms to toxic wastes, parasites, and diseases Developed by: Updated: U5-m21a-s46
- 47. Temperature measurement - probes · Types of probes · Liquid-in-glass · Thermistor: based on measuring changes in electrical resistance of a semi-conductor with increasing temperature. thermistor on a YSI sonde Developed by: Updated: U5-m21a-s47
- 48. Temperature changes · Causes of temperature change include: · weather · removal of shading streambank vegetation, · impoundments (a body of water confined by a barrier, such as a dam) · discharge of cooling water · urban storm water · groundwater inflows to the stream Developed by: Updated: U5-m21a-s48
- 49. Temperature changes - continued Graph showing factors that influence stream temperature, from Bartholow (1989). Developed by: Updated: U5-m21a-s49
- 50. Temperature criteria – example Here’s an example of a temperature TMDL for a California stream Developed by: Updated: U5-m21a-s50
- 51. Temperature criteria – cont. Developed by: Updated: U5-m21a-s51
- 52. Temperature – summer rain storm Summer rainfall event Bump in stream temp (and turbidity) Developed by: Updated: U5-m21a-s52
- 53. Other Water Quality Parameters · Nutrients – nitrogen and phosphorus · Fecal coliforms · Biochemical oxygen demand (BOD) · Metals · Toxic contaminants · Details on analyzing these parameters are in Module 9 – Lake Surveys Developed by: Updated: U5-m21a-s53
- 54. Fecal coliforms · Pathogens are number one Developed by: Updated: U5-m21a-s54
- 55. Water sampling - microbes · Sterile technique: · Containers must be sterilized by autoclaving or with gas used to kill microbes · Take care not to contaminate the container · Water samplers should be swabbed with 70 % alcohol Developed by: Updated: U5-m21a-s55
- 56. Bacteria – E. coli and fecal coliforms · Fecal bacteria are used as indicators of possible sewage contamination · These bacteria indicate the possible presence of disease-causing bacteria, viruses, and protozoans that also live in human and animal digestive systems · E. coli is currently replacing the fecal coliform assay in most beach monitoring programs See Module 9 for a detailed discussion of measuring pathogens Developed by: Updated: U5-m21a-s56
- 57. Water sample collection – grab samples Grab samples for fecal coliforms are taken with sterile containers Developed by: Updated: U5-m21a-s57
- 58. Water sample collection ·General considerations: · Sample in the main current · Avoid disturbing bottom sediments · Collect the water sample on your upstream side · A detailed discussion on how to manually collect stream and river water can be found in the USGS Field Manual Chapter 4: Collection of Water Samples Developed by: Updated: U5-m21a-s58
- 59. Suggested sample volumes Analyte Volume needed chlorophyll >500 mLs TSS Often > 1 L total phosphorus total nitrogen anions 200 to 500 mLs Dissolved nutrients ~ 100mLs Total and dissolved carbon ~60 mLs Metals ~60 mLs color, DOC ~60 mLs Developed by: Updated: U5-m21a-s59
- 60. Stream sampling– sample labeling · An unlabeled sample may as well just be dumped down the drain. · Use good labels not masking tape, etc. Poor labels often fall off when frozen samples are thawed. · Use permanent markers NOT ball point pens, pencils in a pinch Developed by: Updated: U5-m21a-s60
- 61. Lake Stream sampling sampling – sample – sample labeling labeling · A simple sample label with the minimum amount of information needed… project Site, WOW Tischer Creek 7/26/02 Reach 3 RAW, frozen date, location Sample processing and preservation info Often, much more information may be needed by the laboratory performing your analyses. You will also need to supply a chain of custody form. Developed by: Updated: U5-m21a-s61
- 62. Automated stream monitoring Developed by: Updated: U5-m21a-s62
- 63. Water sampling - automated · Automated stream sampling stations provide continuous monitoring of a variety of parameters · These units are capable of both collecting water samples and measure various water quality parameters Developed by: Updated: U5-m21a-s63
- 64. Automated stream samplers · Flow weighted composites · Flow weighted discrete · Sampling triggered by predetermined set point such as: · Flow · Precipitation · Any other parameter measured by in-stream sensors Developed by: Updated: U5-m21a-s64
- 65. Automated sampling – Duluth Streams · These stream monitoring units are not “state of the art” but provide near real-time data for delivery into the data visualization tools Developed by: Updated: U5-m21a-s65
Editor's Notes
- You could probably drop this slide, the next slide covers this
- Business end of a YSI 6800 series sonde (NRRI photo)
- The most commonly measured parameters in streams are related to water quality. Many federal and state laws specify the values that are typical for good and poor water quality. In addition, there are several parameters that are useful for generally characterizing water quality for aquatic life and other beneficial uses of water. Major ions = alkalinity/ANC, SO4, Cl,Ca, Mg, Na, K, Na Anions (negatively charged) Bicarbonate and carbonate (HCO3- and CO3-2 : also called alkalinity and acid-neutralizing capacity or ANC); usually measured together by titration with sulfuric acid) Sulfate (SO4 –2) Chloride (Cl -) Silicate (SiO –3) Cations (positively charged) Mg +2 and Ca +2 (divalent cations) Sodium (Na+) and potassium (K+) Minor ions = nutrients (N and P) Phosphorus: total P (TP), inorganic-P (SRP or ortho-P or PO4 –3), organic P, particulate P Nitrogen: total N (TN), inorganic N (NH4+-N, [NO3- + NO2- ] N), organic N, particulate N
- Dissolved oxygen is essential for fish and invertebrates and is produced by biological transformations and physical processes in water.
- The Winkle titration is a simple and accurate chemical test for DO that has been used for decades, particularly before more sophisticated electronic equipment was affordable and reliable. Photo taken from http://www.lumcon.edu/education/StudentDatabase/gallery.asp Details of the Winkler titration are in Module 9
- Note: very high velocity may also cause inaccuracy (cavitation). To learn how to maintain a DO sensor see Module 9
- Sediment has been cited as the second most important pollutant in streams and rivers of the U.S. Sediment can be both suspended in the water column or it may be deposited on the bottom of a stream. There are specific measuring procedures for both of these locations.
- Sediment gets into stream through a variety of common land uses. soil erosion associated with agricultural practices, construction site runoff domestic and industrial wastewater discharge urban runoff from roads, parking lots and other impervious surfaces flooding and chronically increased flow rates algal growth due to nutrient enrichment dredging operations in the stream itself or in feeder tributaries or ditches channelization removal of riparian vegetation and other stream bank disturbances too many bottom-feeding fish (such as carp) that stir up bottom sediments
- Total Suspended Solids (More detail can be found in Module 9) TSS, or total suspended solids or total suspended sediment is pretty simple in theory. But, like most water quality parameters, it has some methodological problems and choices that require you to think before performing the measurement. The measurement is simple - separate the solids from the water using a piece of filter paper (actually you use a filter that looks like paper but is really made of glass fibers, pressed together; sort of like the fibers in the glass wool that is used for a fish tank). Then the filter plus the material on top of it are dried and weighed. If you remembered to weigh the filter before you used it (called “measuring the tare” or “taring” the filter), you can subtract this weight with the remainder being the weight of the solids. Some technique notes (more are attached to slide #2: 1. Filtration apparatus: A variety are available and vary considerably between the limnology/academic research community and the wastewater lab community. Fritted glass filter support bases work very well and provide a very uniform layer of material, but in time may clog. Our lab prefers plastic frits with fine slots, especially if you can get those with magnetic bases that allow you to place the filtration funnel on without a clamp. (Figure 1). 2. You need to have enough particulate material on the filter to allow you to get a significant weight change (the more the better !), BUT if you try to filter too much water it could take you into tomorrow to filter it and the remember that the pore size is changing. Standard Methods (APHA) recommends that the final weight on the filter pad be 10 to 200 mg.
- It turns out that the filter you choose and how much water you filter may be important. Different brand filters have somewhat different nominal pore sizes and in fact these change as water is filtered and particles gradually plug up the pores. Unfortunately, this is not stated in standard reference manuals such as the various water quality methods “bibles” published by EPA, USGS, the American Public Health Association (see http://wow.nrri.umn.edu/ for list). Under the Federal NPDES program, EPA method 160.2 and Standard Methods 2540D are approved for measuring TSS in effluents or natural waters subject to regulatory requirements for discharges. Commonly used glass fiber filters include Whatman GF/F, GF/C and GF/A (from finer to coarser pores) Reeve-Angel 984-AH and 934 AH (finer-coarser) Gelman AE (approximately similar to Whatman GF/C’s) 4. Because of difference you may get in your TSS numbers just because of the filter you use (the NRRI Lab has found that values can vary by &gt;50%), it is probably better to use the same filters year after year so that long-term trends will not be affected by methodology changes (“glitches” is the technical term). 5. Washing the filter is important because loose material can introduce an error. He filters must be pre-washed, dried and weighed to a constant weight (&lt;0.5 mg variation or &lt;4% of initial weighing). For non-regulatory routine monitoring work, do some preliminary checks to see how big these variations are to allow you to streamline your technique. After the washed filters are dried and tared, we store them in small plastic petri dishes (XX cms diam) that can be labeled with the filter # and weight and date and sample ID and even re-used later.
- http://www.epa.gov/owow/tmdl/examples/sediment/ks_slatesilt.pdf
- Details on how to calibrate a turbidity sensor are in Module 9
- Reference: (from http://www.bradwoods.org/eagles/turbidity.htm (Aug 2002)) Turbidity is due to: Inorganic particles such as clays and silts Organic material, both living and detrital, autocthonous and allocthonous The Relationship between Among JTU&apos;S, and NTU&apos;sThe Secchi disk measurement in feet has been roughly correlated with Jackson Turbidity Units (JTU&apos;s). These units were based upon a standard suspension of 1000 parts per million diatomaceous earth in water. By diluting this suspension, a series of standards was produced. Jackson Turbidity Units (JTU&apos;s) are the application of these standards to the original device for measuring turbidity called the “Jackson tube.” The Jackson tube is a long glass tube suspended over a lit candle. A sample of water was slowly poured into the tube until the candle flame as viewed from above could no longer be seen. This device is no longer used because it is not sensitive to very low turbidities. A turbidimeter measures turbidity as nephelometer turbidity units (NTU). Instruments such as the turbidimeter that measure the scattering of light are called nephelometers. Both NTU&apos;s and JTU s are interchangeable units. They differ only in that their name reflects the device used to measure turbidity.
- SALMON CREEK WATERSHED http://oaspub.epa.gov/pls/tmdl/waters_list.tmdl_report?p_tmdl_id=1363 http://www.epa.gov/owow/tmdl/examples/
- How does turbidity relate to TSS ? Also remember that plankton contribute to turbidity as well and that living cells are &gt; 70 % water. A sample with high turbidity due to plankton may NOT correlate well to TSS as one with particulates due to erosional or resuspended silt. See also http://www.duluthstreams.org/understanding/param_turbidity.html for a discussion focusing on stream turbidity and TSS.
- Summary information for three western Washington streams during 1988-89 http://www.ecy.wa.gov/programs/wq/plants/management/joysmanual/streamtss.html
- REFERENCES: 1. USEPA Estuary Volunteer Monitoring Manual, Chapter 15: Turbidity and Total Solids: Procedure C—Measuring water clarity with a transparency tube http://www.epa.gov/owow/estuaries/monitor/chptr15.html#measure 2. Minnesota Pollution Control Agency. 2001. Citizen Stream-Monitoring Program: Year 2000 Report on the Water Quality of Minnesota Streams. December 2001, Environmental Outcomes Division, Minnesota Pollution Control Agency, St. Paul, MN 55155, USA. http://www.pca.state.mn.us/water/csmp-reports.html 3. Globe Program. 2002 (website). Hydrology Chapter: Water Transparency Protocol. NOAA/Forecast Systems Laboratory, Boulder, Colorado USA (http://www.globe.gov/sda-bin/wt/ghp/tg+L(en)+P(hydrology/WaterTransparency). July 2002. Turbidity Tube Theory & Operation The turbidity tube is a relatively new tool increasingly being used by volunteer stream monitoring programs. It provides an analogous measure of turbidity in streams to the secchi depth in lakes. The earliest reference I have found to its use is from the GLOBE program which is an international environmental education program designed for elementary, middle and high school kids. However, the Minnesota Pollution Control Agency’s Citizen Stream Monitoring Program credits Australian stream ecologists with introducing this tool (citation above). Tubes can now be purchased from many vendors (do a web search for information) and a number of states have set up stream monitoring programs that use them. NRRI is using them in a study of Laurentian Great Lakes coastal wetlands and nearshore zones (2001-2003 data collections) and developing relationships between turbidity tube transparency, TSS and turbidity. They typically come in 60 and 120 cm sizes and we recommend the 120 cm tubes to allow you to obtain data from clearer systems. The Minnesota Pollution Control Agency has had a program since 1999 and publishes a useful document on-line that includes annual data as well as supporting information (http://www.pca.state.mn.us/water/csmp.html). Their basic tube has been only 60 cms which worked well for impacted streams. Since 2001 they have been cross comparing 60 cm with 100 cm tubes. Theory: Stream water transparency is an indirect measure of the concentration of dissolved and suspended materials. For most water bodies, light is attenuated mostly by suspended particulates (TSS = total suspended solids). In lakes, this TSS is mostly algae (phytoplankton). In streams and rivers, the TSS is mostly soil particles (predominantly silts and clays) that eroded from the watershed or stream channel. A low transparency reading reflects high levels of sediment (excess soil and/or algae) in the water. This excess sediment is a pollutant since it: reduces light penetration needed for the growth of beneficial aquatic plants and for fish and invertebrates to feed; it can smother fish eggs, keeping them from getting the oxygen needed to survive as well as contributing excess oxygen demand from the decomposition of its organic matter; it clogs spaces between rocks where aquatic insects live; and it also adsorbs and transports other pollutants contributed by urban and agricultural runoff such as phosphorus, petroleum products, heavy metals, and microbial pathogens. These pollutants degrade the quality of flowing water, as well as downstream lakes or reservoirs. Note - Although this section focuses on streams, the same comments and precautions would apply to ponds, wetlands and coastal zone waters although there is little available information as yet. Operation: Simple – Set the tube on a white towel. Slowly pour the well mixed water sample into the tube, stopping intermittently to see if the black and white pattern has disappeared. To avoid introducing air bubbles, pour the water against the inside wall of the tube. With your back to the sun (avoid direct sunlight by shielding the tube with your body), use your toes to control the valve at the bottom and release water until you can see the mini-secchi disk on the bottom stopper. Record the water depth in centimeters as marked on the side of the tube. If you can see the secchi when the tube is full, record the datum as &gt;120 cm (or &gt;60 cm for the short tube).
- Precautions: Readings in transparency tubes can be rendered inaccurate (in the sense of estimating turbidity and suspended particulate material) in cases of highly colored waters. A transparency reading taken from one tube cannot be compared with a reading taken from another tube from a different manufacturer if the dimensions are different. It may take a number of tries because of overshooting the endpoint so collect plenty of water for this analysis. Our standard 120 cm x ~4.5 cm O.D. tube requires ~ 1.5 liters to fill it so we dedicate at least 4 liters of water (cubitainers and Supermarket 1 gallon “distilled/deionized water” water jugs work well). Although many commercially available tubes have valves tubes at the bottom that we control with our toes, it’s easy to overshoot the mark and so you need extra water. Be sure to vigorously mix the sample before and during filling – fast settling sand and larger silt particles may require replicate measurements. However, take care not to produce air bubbles which will scatter light and affect the measurement. Be sure to save an adequate amount of water from the same site to be able to determine TSS and/or nephelometric turbidity (see Module 8 Methods) as a calibration. The rubber stoppers (with attached secchi) can pop out pretty easily. Tape it with black vinyl electricians tape and carry an extra stopper-secchi Tubes won’t last forever, especially if not cleaned periodically with mild dish soap and a cotton wash rag. Although water from the tube could be saved for turbidity and TSS measurements, do NOT save it for nutrient or many other pollutant analyses because it has not been cleaned according to certified protocols. Sample collection – SEE MODULE 7 - #xxx for sampling considerations. For streams, collect the sample in a bottle or bucket at mid-depth if possible, avoid stagnant water, sample as far from the shoreline as is safe, and avoid collecting bottom sediment. Particles settle fast so subsampling and settling are important issues. A big stopper for the top is useful to allow for resuspension during the measurement if there are lots of rapidly settling sediments. Avoid sunglasses and avoid direct sunlight by shielding the tube with your body when possible. Similar suspended sediment concentration waters can have very different transparency since smaller particles scatter more light Dissolved color due to organic matter (humic and fulvic acids usually from bogs and conifer needles) can confound stream to stream or wetland to wetland comparisons of turbidity. Although this section focuses on streams, the same comments and precautions would apply to ponds, wetlands and coastal zone waters although there is little available information as yet.
- From: IF VISUAL WATER CLARITY IS THE ISSUE, THEN WHY NOT MEASURE IT? Davies-Colley, R. J. and D.G Smith, 2001. Turbidity, Suspended Sediment, and Water Clarity: A Review. Journal of the American Water Resources Association 37: 1085-1101.
- Increased embeddedness decreases the living space between particles and limits the available area and cover for small fish, macroinvertebrates, and periphyton. Siltation can also smother fish eggs Reference: An Evaluation of Techniques for Measuring Substrate Embeddedness by Traci Sylte and Craig Fischenich http://stream.fs.fed.us/news/streamnt/oct03/oct_03_01.htm
- Simonson, T.D., J. Lyons and P.D. Kanehl. 1994. Guidelines for Evaluating Fish Habitat in Wisconsin Streams. USDA Forest Service Technical Report NC-164. 36pp.
- A relatively simple method of assessing several chemical characteristics of streams is through measuring electrical conductivity.
- A water sample consists of pure water containing various dissolved substances (gases and solids), and particulates (substances not dissolved in the water). These fractions may be functionally defined by passing the water through a fine filter to remove the solids (see TSS section in Module 8 for specific filtration details). The total amount of solids dissolved in the water as ions and other molecules = the total dissolved solids or TDS. It’s measured simply by filtering out the particulates, evaporating the water in a pre-weighed dish, and then weighing the residual solids from the known volume of sample. Units are milligrams per liter (mg/l). Note that the weight of dissolved gases is not included in the TDS. Note also that if we weighed the solids caught on the filter, we would have a value for TSS (total suspended solids) in the same sample. Note that some fine particulates may pass through the filter (depending on its effective (also called nominal) pore size and so would be erroneously included in the TDS. Conductivity indirectly estimates the TDS based on how well the water sample conducts an electrical current, a property which is proportional to the concentration of ions in solution. Salinity is a parameter used primarily to characterize marine or estuarine water TDS based upon concentration of ocean salts. Technically, the measurement of salinity requires comparing a sample&apos;s TDS or conductivity, or other physico-chemical property with that of a standard sea water. Salinity is the usual measure of salts in sea water and in brackish water derived from mixing of fresh and sea water in estuaries.
- Re: Temperature compensation: EC increases with increasing temperature. Therefore, even if a water body had a constant salt concentration its EC would decrease in winter and with depth in the summer. However, in most cases, we want to use EC as a measure of the total salt concentration of a sample and so we remove this temperature variation by normalizing (also called standardizing) the readings to what they would be if the sample were measured at 25 oC . We then call it specific EC and abbreviate it as EC@ 25 oC or just EC25. BE CAREFUL when you examine other people’s data – they often fail to specify what their probe was measuring. Many older instruments, in particular the YSI 33 S-C-T meter that has been a faithful instrument for many decades, are not temperature compensated and require re-calculation after the fact. In stratified lakes as the summer progresses the telltale clue is a decreasing EC with depth below the thermocline that is due to decreasing temperatures. In fact EC25 typically increases with depth in the hypolimnion over the course of the summer due to the buildup of bicarbooate and other ions by bacterial repiration and remineralization (I.e. decomposition) activity.
- What in the world are microSiemens per centimeter (µS/cm)? (http://waterontheweb.org/under/waterquality/conductivity.html) These are the units for electrical conductivity (EC). The sensor simply consists of two metal electrodes that are exactly 1.0 cm apart and protrude into the water. A constant voltage (V) is applied across the electrodes. An electrical current (I) flows through the water due to this voltage and is proportional to the concentration of dissolved ions in the water - the more ions, the more conductive the water resulting in a higher electrical current which is measured electronically. Distilled or deionized water has very few dissolved ions and so there is almost no current flow across the gap (low EC). As an aside, fisheries biologists who electroshock know that if the water is too soft (low EC) it is difficult to electroshock to stun fish for monitoring their abundance and distribution. For their purposes in selecting the right size shocker, they want to know the actual EC value, not the temperature compensated value. Up until about the late 1970&apos;s the units of EC were micromhos per centimeter (µmhos/cm) after which they were changed to microSiemens/cm (1 µS/cm = 1 µmho/cm). You will find both sets of units in the published scientific literature although their numerical values are identical. Interestingly, the unit &quot;mhos&quot; derives from the standard name for electrical resistance reflecting the inverse relationship between resistance and conductivity - the higher the resistance of the water, the lower its conductivity. This also follows from Ohm’s Law, V = I x R where R is the resistance of the centimeter of water. Since the electrical current flow (I) increases with increasing temperature, the EC values are automatically corrected to a standard value of 25°C and the values are then technically referred to as specific electrical conductivity. All WOW conductivity data are temperature compensated to 25°C (usually called specific EC). We do this because the ability of the water to conduct a current is very temperature dependent. We reference all EC readings to 25°C to eliminate temperature differences associated with seasons and depth. Therefore EC 25°C data reflect the dissolved ion content of the water (also routinely called the TDS or total dissolved salt concentration).
- SourcesEC25 is also one of a number of general indicators of the overall “health” of a stream and variations from its normal range may indicate sources of pollution such as: wastewater from sewage treatment plants and industrial discharges. These are point sources of pollutants. Domestic sewage is enriched by human wastes in addition to food, laundry and other materials that find their way down household drains. Depending on the municipality, a variety of industrial wastewaters that have been pre-treated to varying degrees, are then mixed with the domestic wastewater prior to treatment. However, treatment at this stage usually has little effect on TDS since the primary goals are to break down organic matter, remove particulate materials, remove nutrients (phosphorus and nitrogen) and disinfection. Some industrial wastes are extremely salty, to the point of being called “brines”, and require expensive pre-treatment to prevent the high TDS levels from harming the microorganisms that are the main sewage treatment process . wastewater from on-site wastewater treatment and dispersal systems (septic systems and drainfields) urban runoff from roads and construction sites (especially road salt; see winter storm graph from Chester Creek, November 2002). This source has a particularly episodic nature with pulsed inputs when it rains or during more prolonged snowmelt periods. It may &quot;shock&quot; organisms with intermittent extreme concentrations of pollutants which seem low when averaged over a week or month. Road de-icing salts can be quite varied but typically are mostly sodium chloride (NaCl) and magnesium chloride (MgCl2). agricultural runoff of water draining agricultural fields typically has extremely high levels of dissolved salts (another major nonpoint source of pollutants). Although nutrients (ammonium-nitrogen, nitrate-nitrogen and phosphate from fertilizers) and pesticides (insecticides and herbicides mostly) comprise a minor fraction of the total dissolved salts, their concentrations are greatly elevated relative to natural ecosystems and typically cause significant negative impacts on streams and lakes receiving agricultural drainage water. High EC25 values are also often associated with increased soil erosion. Soils washed into receiving waters also add oxygen depleting organic matter in addition to nutrients and pesticides. acid mine drainage - drainage from operating and abandoned mine sites can contribute iron, sulfate, copper, nickel, cadmium, arsenic, and other compounds if minerals containing these constituents are present and are exposed to air and water. The high TDS of mine drainage in coal and metal mines in particular is well known to cause serious ecological damage in some parts of the U.S. Acid mine drainage, often referred to as AMD, results when the mineral pyrite (FeS2) is exposed to air and water, resulting in the formation of sulfuric acid and iron hydroxide. The combination of high acidity, high TDS (sulfate usually) and iron coatings can be devastating to stream communities. Pyrite is usually present in coal-mining and many metal mining areas. AMD becomes a problem when the overlying rocks are exposed and removed during surface mining to get to the coal. Minnesota&apos;s Iron Range iron mining area has had little impact from AMD except for mineralized (sulfide-bearing rock) Duluth Complex waste rock piles at the Dunka Pit iron mine near Babbitt, MN which have required a variety of treatment methods to protect downstream water resources. atmospheric inputs of ions are typically small except near seashores where ocean water increases the salt load ( &quot;salinity&quot; ) of precipitation. Sea spray can also be important and this oceanic effect can extend inland about 50-100 kilometers and be predicted with reasonable accuracy.
- From http://www.duluthstreams.org/understanding/param_ec.html This graph summarizes some of the results from a snowmelt runoff study conducted by MPCA-Duluth staff in 1999 for Kingsbury Creek, Amity, Keene and Miller Creeks (MPCA 2000). Their first sample on March 25 was collected when the spring runoff had just begun and flow was still relatively low (9 cfs). Both EC25 and TDS were at their highest levels in this study due to road salt loads that washed into the stream with the first flush of snowmelt. Four days later these levels had decreased sharply due to dilution when streamflow jumped from 9 to over 90 cfs due to warm weather. After another 4 days, flows had dropped, but were still high and so EC25 and TDS remained relatively low. A final set of samples was collected in late September during the very low base-flow period and EC25 and TDS were higher since groundwater seepage comprised most of the flow at this time. Similar patterns were observed at the other streams. Additional sampling at Miller Creek by the South St. Louis County Soil and Water Conservation District (SSLSWCD) prior to the peak spring runoff showed much higher salt levels. This clearly demonstrated that the large load of urban pollutants that can accumulates over the winter when the stream is mostly frozen, can be suddenly released and potentially ”shock” fish and other aquatic organisms.
- pH is an essential chemical measurement to take while collecting water quality samples because it influences an number of important chemical and biological process. Image courtesy of USGS at http://www.usgs.gov/
- Review: For example, in addition to affecting how much and what form of phosphorus is most abundant in the water, pH may also determine whether aquatic life can use it. In the case of heavy metals, the degree to which they are soluble determines their toxicity. Metals tend to be more toxic at lower pH because they are more soluble.
- Details of pH measurement and probe calibration can be found in Module 9.
- Details on temperature measurement and probe calibration can be found in Module 9. Absolutely NO mercury (Hg) thermometers, existing Hg thermometers should be turned in at your state water quality agency. Temperature is always measured concurrently with oxygen, pH, and conductivity because all of these parameters are temperature dependent. Most sensors have built-in temperature compensation.
- Thermal pollution (i.e., artificially high temperatures) in larger streams usually occurs as a result of discharge of municipal or industrial effluents. Except in very large lakes, it is rare to have an effluent discharge. In urban areas with smaller streams runoff that flows over hot asphalt and concrete pavement before entering a stream or pond will be artificially heated and can cause significant warming. In running waters, particularly small urban streams during low flow periods, elevated temperatures from road and parking lot runoff can be a serious problem for populations of cool or cold-water fish already stressed from the other contaminants in urban runoff. During summer, temperatures may approach their upper tolerance limit. Higher temperatures also decrease the maximum amount of oxygen that can be dissolved in the water, leading to oxygen stress if the water is receiving high loads of organic matter. Since trout eggs require cool, well oxygenated water, reproduction may be directly impaired by this pollutant in addition to its effects on adult and juvenile fish survival. Since bacteria and other disease causing organisms grow faster in warm water, the susceptibility of aquatic organisms to disease in warm water increases as well. Water temperature fluctuations in streams may be further worsened by cutting down trees, which provide shade, and by absorbing more heat from sunlight due to increased water turbidity.
- Image taken from: http://www.krisweb.com/stream/temperature.htm#factors Bartholow, J.M. 1989 . Stream temperature investigations: field and analytic methods. Instream flow information paper no. 13. Biological Report 89(17). U.S. Fish and Wildlife Service, Fort Collins, Co
- http://www.epa.gov/owow/tmdl/examples/sediment/ca_navarro.pdf
- Maximum average temperatures for growth and short-term maximum temperatures for selected fish http://www.epa.gov/owow/monitoring/volunteer/stream/vms53.html References: Brungs, W.S. and B.R. Jones. 1977. Temperature Criteria for Freshwater Fish: Protocols and Procedures. EPA-600/3-77-061. Environ. Research Lab, Ecological Resources Service, U.S. Environmental Protection Agency, Office of Research and Development, Duluth, MN.
- Example of how urban runoff during a summer rainstorm can cause an increase in stream temperatures. http://www.duluthstreams.org/streams/data/
- See Module 9 for more detailed information on pathogen monitoring REFERENCES 1. US Geological Survey (USGS), Water Resources--Office of Water Quality, National Field Manual Chapter 7.1 FECAL INDICATOR BACTERIA http://water.usgs.gov/owq/FieldManual/Chapter7.1/7.1_contents.html 2. http://ohioline.osu.edu/b795/b795_2.html
- Whirlpak©bags, and autoclavable polypropylene and glass bottles work well. Use sterile gloves to protect the sample and yourself.
- These indicator bacteria are generally not considered harmful by themselves although some can be pathogenic (disease causing).
- Details in Module 9
- http://water.usgs.gov/owq/FieldManual/chapter4/html/Ch4_contents.html The following text adapted from the EPA Volunteer Stream Monitoring Methods Manual (http://www.epa.gov/volunteer/stream/vms50.html). Sample away from the streambank in the main current. Never sample stagnant water. The outside curve of the stream is often a good place to sample, since the main current tends to hug this bank. In shallow stretches, carefully wade into the center current to collect the sample. Disturb bottom sediment as little as possible. In any case, be careful not to collect water that has sediment from bottom disturbance. Stand facing upstream. Collect the water sample on your upstream side, in front of you. A boat will be required for deep sites. Try to maneuver the boat into the thalweg to collect the water sample.
- Some suggested sample volumes. True needs are based upon the specific analytical method requirements. Make sure you allow for volume loss during sample processing (e.g. filtration).
- We (NRRI and WOW) use Tyvek type labels but many others are available.
- Often, much more information may be needed by the laboratory performing your analyses. You may also need to supply a chain of custody form.
- This module will not cover automated stream sampling in depth. The standard in automated stream sampling is set by the USGS. USGS 1998. National Field Manual for the collection of water quality data. Chapter A2: Selection of equipment for water sampling. TWRI Book 9.
- The Duluth Streams monitors are described at: http://waterontheweb.org/under/instrumentation/smu.html