PROGRAMS AND PLANS--National Hydrologic Benchmark Network: Fiscal Year 1996--October 1, 1995 to September 30, 1996 In Reply Refer To December 4, 1995 Mail Stop 412 OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM NO. 96.02 Subject: PROGRAMS AND PLANS--National Hydrologic Benchmark Network: Fiscal Year 1996--October 1, 1995 to September 30, 1996 This memorandum contains an outline of Program status and protocol for operation of the Hydrologic Benchmark Network (HBN) for fiscal year (FY) 1996. All personnel responsible for collecting HBN samples should read and have their own copy of this memorandum. Network data collection can be significantly enhanced when personnel responsible for field data collection are informed of changes in sample collection and processing procedures. NETWORK OPERATIONS, FY 1996 HYDROLOGIC BENCHMARK NETWORK Sampling frequency for all stations in the Benchmark Network will be QUARTERLY in FY 1996; this is subject to change depending on funding availability. The three stations that were discharge only (02178400--Tallulah River near Clayton, GA; 05014500--Swiftcurrent Creek at Many Glacier, MT; 06478540--Little Vermilion River near Salem, SD) are discontinued as part of the Benchmark Program as of October 1, 1995. Active stations are listed in Appendix A. Districts are encouraged to use the sample collection and processing protocol for filtered samples (OWQ Technical Memorandum 94.09) if they are equipped and ready to do so. Decreasing budgets and increasing costs continue to be a problem. Therefore, the Benchmark Program will be evaluated during FY 1996 and changes in the number of stations and the way they are operated are likely in FY 1997. NOTES for FY 1996: 1. Field Alkalinity The results of the National Field Quality Assurance proficiency tests show that field personnel continue to have problems determining alkalinity in the field, especially with the Hach titrator. The Hach titrator method for determination of alkalinity is documented in Appendix C. All individuals collecting Network samples should be familiar with the method. 2. Sediment Samples Suspended-sediment concentration and sand-fine split are required for all NASQAN and Benchmark samples. Samples for sediment analysis are to be collected in a separate set of bottles (to be composited at the sediment lab), and are NOT to be taken from the churn splitter. If NAWQA samples are being collected at the same time as HBN samples, and a cone splitter is being used, the sediment sample can collected from the cone splitter. See Open-File Report 86-531 (Field Methods for Measurement of Fluvial Sediment by Edwards and Glysson) for details on collection of sediment samples. 3. Samplers Tests of existing samplers to determine their acceptability for collection of trace-element samples have shown that all samplers, except the D-77 and frame samplers (with a teflon or polypropylene bottle and/or a teflon or Reynolds oven bag) and the DH-81 (with a teflon or polypropylene bottle), contaminate samples at levels that are significant at the microgram per liter (parts per billion) level. OWQ realizes that these samplers cannot accommodate all environmental conditions; the Instrumentation Committee (ICOM) has recommended development of additional, non-contaminating samplers and the Federal Interagency Sedimentation Project (FISP) is in the process of developing a 1-L non-contaminating sampler. All samplers being used for the collection of trace-element samples (including weighted-bottle samplers) are to be coated. The FISP now uses a Plasti-Dip coating on all new samplers. Older samplers can be recoated, if necessary. Contact Wayne O'Neal at FISP for more information. His phone number is 601-634-3735. 4. Barometric Pressure Barometric pressure is to be measured with a pocket altimeter-barometer and the value recorded on the field sheet and stored in the data base (parameter code 00025). Barometric pressure can be read and reported to the nearest 1 mm Hg, unless the barometer that is used is not sufficiently accurate. The barometers that are currently available from HIF are accurate to +/- 0.5 mm Hg. Make sure that the barometer is properly calibrated using the UNCORRECTED or STATION pressure that is obtained from the nearest National Weather Service office. Note that the pressure reported on radio and television is corrected to sea level. 5. Recording Field Measurement Information The times that individual field measurements are made, the location of the measurements (from churn, side of stream, center of flow, point sample, depth-integrated sample), and the method used should be recorded on the field sheets. Because field measurements are often made some time before or after the chemical-quality sample is collected, it is important to note the time(s) (even though it cannot be stored in the NWIS I data base). Dissolved oxygen should be measured at the center of flow whenever possible. Use of the National Field Forms is recommended. They are available from the QW Service Unit in Ocala (edoc to OCALAMAN). 6. Bacteria Every effort should be made to obtain bacteria counts in the ideal range. Keeping records of flow, volumes filtered, and counts in the field folder, and referring to them each time bacteria samples are processed should help in obtaining ideal counts most of the time. If counts are consistently low, and sediment does not interfere, volumes greater than 100 mL can be filtered. See TWRI Book 5, Chapter A4 for correct methods for calculating bacteria counts. 7. Storing Sampler Type in Data Base In light of the concerns about potential contamination from samplers, it is very important that the type of sampler used be known. This information can be provided by storing SAMPLER TYPE under parameter code 84164. Currently-available values for this code are given below. Because of the limitations of NWIS I, only the type of sampler used for collecting chemical samples needs to be stored. Note-- these are the correct codes; the codes on the National Field Form are incorrect. 84164 100.00VAN DORN SAMPLER 84164 110.00SEWAGE SAMPLE 84164 120.00VELOCITY INTEGRATED SAMPLE 84164 125.00KEMMERER BOTTLE 84164 3001.00Sampler, US DH-48 84164 3002.00Sampler, US DH-59 84164 3003.00Sampler, US DH-75P 84164 3004.00Sampler, US DH-75Q 84164 3005.00Sampler, US DH-76 84164 3006.00Sampler, US D-43 84164 3007.00Sampler, US D-49 84164 3008.00Sampler, US D-49AL 84164 3009.00Sampler, US D-74 84164 3010.00Sampler, US D-74AL 84164 3011.00Sampler, US D-77 84164 3012.00Sampler, US P-46 84164 3013.00Sampler, US P-50 84164 3014.00Sampler, US P-61-A1 84164 3015.00Sampler, US P-63 84164 3016.00Sampler, US P-72 84164 3017.00Sampler, US U-59 84164 3018.00Sampler, US U-73 84164 3019.00Sampler, US PS-69 84164 3020.00Sampler, US PS-69TM 84164 3021.00Sampler, US CS-77 84164 3022.00Sampler, US PS-82 84164 3023.00Sampler, US BMH-53 84164 3024.00Sampler, US BMH-53TM 84164 3025.00Sampler, US BM-54 84164 3026.00Sampler, US BM-54TM 84164 3027.00Sampler, US BMH-60 84164 3028.00Sampler, US BMH-60TM 84164 3029.00Sampler, US RBM-80 84164 3030.00US DH-48 TM 84164 3031.00US DH-48 TM W/ TEFLON GASKET AND NOZZLE 84164 3032.00US DH-59 TM 84164 3033.00US DH-59 TM W/ TEFLON GASKET AND NOZZLE 84164 3034.00US DH-76 TM 84164 3035.00US DH-76 TM W/ TEFLON GASKET AND NOZZLE 84164 3036.00US D-74 TM 84164 3037.00US D-74 AL-TM 84164 3038.00US D-74 AL-TM W/ TEFLON GASKET AND NOZZLE 84164 3039.00US D-77 TM 84164 3040.00US D-77 TM MODIFIED TEFLON BAG SAMPLER 84164 3041.00US P-61 AL-TM 84164 3042.00US P-61 84164 3043.00US P-61 TM 84164 3044.00US DH-81 84164 3045.00US DH-81 WITH TEFLON CAP AND NOZZLE 84164 3050.00TEFLON BAG SAMPLER 84164 3060.00WEIGHTED-BOTTLE SAMPLER 84164 3070.00GRAB SAMPLE 84164 4010.00THIEF SAMPLER 84164 4020.00OPEN-TOP BAILER 84164 4025.00DOUBLE-VALVE BAILER 84164 4030.00SUCTION PUMP 84164 4035.00CENTRIFUGAL PUMP 84164 4040.00SUBMERSIBLE PUMP 84164 4041.00SUBMERSIBLE HELICAL ROTOR PUMP 84164 4045.00SUBMERSIBLE GEAR PUMP 84164 4050.00SQUEEZE PUMP 84164 4060.00GAS RECIPROCATING PUMP 84164 4070.00GAS LIFT 84164 4075.00PISTON PUMP 84164 4080.00PERISTALTIC PUMP 84164 4090.00JET PUMP 84164 4095.00LINE-SHAFT TURBINE PUMP 84164 8000.00NONE 84164 8010.00OTHER 8. Storage of Sampling Method in Data Base Data analysis requires as much knowledge about a sample as possible. Information on the method used to collect the sample is very useful. SAMPLING METHOD is to be stored under parameter code 82398. Values for this code are given below. 10.00EQUAL WIDTH INCREMENT (EWI) 20.00EQUAL DISCHARGE INCREMENT (EDI) 25.00TIMED SAMPLING INTERVAL 30.00SINGLE VERTICAL 40.00MULTIPLE VERTICALS 50.00POINT SAMPLE 60.00WEIGHTED BOTTLE 70.00GRAB SAMPLE (DIP) 90.00DISCHARGE INTEGRATED, CENTROID 120.00VELOCITY INTEGRATED 8010.00OTHER 9. Storing Sample Purpose Code in Data Base A value for parameter code 71999 (Sample Purpose Code) is to be stored with all HBN samples. The following value is to be used: 30.00 = Benchmark Use of this code will allow identification and retrieval of Network samples for data analysis. If samples are collected at Benchmark stations for purposes other than National Network operations, the sample purpose code should not be 30.00. 10. Preservatives The only preservative now required for National Network samples is nitric acid for the FA bottle. For schedules 176 and 177, The 1-mL glass or teflon ampoules containing ultrapure nitric acid are to be used. Handle ampoules carefully and dispose of them according to the method outlined in OWQ Tech Memos 90.01 and 92.11. This will reduce potential sample contamination. If a sample processing chamber is being used, the nitric acid preservation can be done in the chamber after all sample processing is completed. The chamber bag should then be disposed of. 11. Shipping Samples Bottles for nutrient analyses (RCC and FCC -- 125 mL brown bottles) are to be shipped to the National Water Quality Laboratory in a cooler with plenty of fresh ice. The cooler should be lined with a plastic bag that is then tied or sealed at the top to prevent leakage. The nutrient samples are to be shipped to the lab immediately after sample collection, preferably from the field, by overnight delivery. The Analytical Services Request Form should be sealed in a zip-lock bag and included in the cooler (taped to the inside of the lid) with the sample bottles. A postcard requesting the arrival date and temperature of the sample can be placed in the zip-lock bag. Lab personnel will fill out the information and return the postcard to the District. This will enable you to determine that the samples remained chilled to about 4 degrees Celsius during shipping. Although it is no longer necessary to separate the nutrient samples from other samples, all other samples can be shipped unchilled in a cooler or box. Make sure that each container has a separate Analytical Services Request Form (ASR). The latest revision of the ASR is in tablets with a blue cover. Books (of 50) forms can be obtained by sending edoc to DENSUPPL. There is no charge for the forms. Older versions of the ASR should not be used. Shipping charges are paid by the Districts, either directly or billed by the laboratory. Information on shipping samples is contained in a memorandum dated September 17, 1991, from the Assistant Chief Hydrologist for Operations. A copy can be obtained from your District administrative officer. 12. Bottle Types Following is a list of bottle types and the analyses that are done from each. Individuals processing Network samples should be aware of this information as means of preventing sample contamination. Note that the FAM bottle will not be required again this year. Schedule 86 - Nutrients FCC - 125 mL, brown poly, filtered, chilled to 4oC Nitrogen, dissolved, NO2 + NO3 as N (00631) Nitrogen, dissolved, NH4 as N (00608) Nitrogen, dissolved, NO2 as N (00613) Phosphorus, dissolved, ortho as P (00671) Phosphorus, dissolved as P (00666) RCC - 125 mL, brown poly, chilled to 4oC Nitrogen, total, NH4 + organic as N (00625) Phosphorus, total as P (00665) Schedule 1703 - Radiochemicals FAR - 2 L poly, acid rinsed, filtered, treated with 2 mL nitric acid (or amount necessary to obtain pH <2) Radium-226, dissolved (09511) Uranium, dissolved, ext, LIP, FF (22703) Schedule 176 - Physical properties, common and trace dissolved inorganic constituents FA - 250 mL poly, filtered, treated with 1 mL nitric acid (glass ampoule) (or amount necessary to obtain to pH <2) Aluminum (01106) Molybdenum (01060) Barium (01005) Nickel (01065) Calcium (00915) Potassium (00935) Cobalt (01035) Selenium (01145) Iron (01046) Silver (01075) Lithium (01130) Sodium (00930) Magnesium (00925) Strontium (01080) Manganese (01056) Vanadium (01085) FU - 500 mL poly, filtered, untreated Silica (00955) Sulfate (00945) Fluoride (00950) Chloride (00940) ROE at 180 C (70300) LC00050 - 125 mL poly, untreated Turbidity, NTU (00076) RU - 250 mL poly, untreated pH, laboratory (00403) Specific conductance, laboratory (90095) Alkalinity, total, laboratory (00417) Schedule 177 - Physical properties, common and trace dissolved inorganic constituents FA - 500 mL poly, filtered, treated with 2 mL nitric acid (glass ampoule) (or amount necessary to obtain to pH <2) Aluminum (01106) Molybdenum (01060) Barium (01005) Nickel (01065) Calcium (00915) Potassium (00935) Cobalt (01035) Selenium (01145) Iron (01046) Silver (01075) Lithium (01130) Sodium (00930) Magnesium (00925) Strontium (01080) Manganese (01056) Vanadium (01085) FU - 500 mL poly, filtered, untreated Silica (00955) Sulfate (00945) Fluoride (00950) Chloride (00940) ROE at 180 C (70300) LC0050 - 125 mL poly, untreated Turbidity, NTU (00076) RU - 250 mL poly, untreated pH, laboratory (00403) Specific conductance, laboratory (90095) Alkalinity, total, laboratory (00417) 13. Water-Quality Field Techniques References Below is a list of Office of Water Quality Technical Memoranda and additional references that describe the techniques that are to be used in the collection and processing of water-quality samples. These references should be available to all people collecting water- quality samples. Office of Water-Quality Technical Memoranda Number Date Subject 70.07 11-28-69 Quality control of water analyses: water-quality service units and mobile laboratories 71.04 1-13-71 Methods for collection and analysis of water samples for dissolved minerals and gases (TWRI book 5, Ch. A1) 71.05 3-18-71 Sampling and analysis of water-quality constituents associated with suspended solids 71.09 6-22-71 Guidelines for sampling and analysis of water-quality constituents associated with solids 72.04 11-08-71 Instructions for use of sediment samplers for the collection of samples to be analyzed for organic substances 72.09 1-05-72 Preservation of water samples for chemical analysis (superceded by 80.26) 72.13 2-28-72 Computations of fluvial-sediment discharge (TWRI book 5, Ch. C3) 73.02 9-11-72 Field determinations (superceded by 82.06) 73.07 10-26-72 Teflon sample splitters and plastic sleeves 73.16 4-23-73 Sampling procedures and problems in determining pesticide residues in the hydrologic environment 74.11 2-28-74 Field instruction for NASQAN 75.09 12-26-74 Acceptable methods for collection of water-quality data 75.15 3-13-75 Publication of water temperatures 75.25 6-19-75 Guidelines on sampling and statistical methodologies for ambient pesticide monitoring 76.03 10-14-75 Water-quality field instrumentation 76.17 5-12-76 Sampling mixtures of water and sediment in streams 76.24-T 8-16-76 Sample splitter for water-sediment samples 77.01 12-13-76 Sample splitter for water-sediment samples (cleaning instructions) (supplements 76.24T) 77.03 1-17-77 DH-75 suspended-sediment sampler 77.07 4-06-77 Guidelines for application of Helley-Smith bedload sampler 77.08 5-06-77 Relationship of sediment discharge to streamflow 78.03 1-17-78 Churn splitters (supplements 76.24T and 77.01) 78.06 4-05-78 Field filtering of water samples for chemical analyses 78.13 7-10-78 Microbiological monitoring for water-quality assessment 79.06 12-11-78 Shipment of hazardous material 79.08 3-07-79 Modification of the field chamber for the YSI dissolved oxygen meter 79.10 3-14-79 Recommended procedures for calibrating dissolved oxygen meters 79.15 9-11-79 Data networks; unique number identification for federally funded stations 79.16 9-28-79 Quality assurance of temperature measurements 79.17 10-02-79 Use of Helley-Smith bedload sampler 80.03 11-19-79 Samplers--P-61 and P-63 point-integrating sediment samplers 80.06 1-24-80 Color-coded nozzles for sediment samplers 80.07 2-05-80 Use of Helley-Smith sampler 80.16 6-02-80 Quality assurance program for sediment laboratories 80.17 7-03-80 New sample splitter for water-quality samples (cone splitter) 80.18 6-13-80 Samplers-- problems with installation of plastic nozzles on samplers 80.26 9-19-80 Preservation of nutrient samples by addition of mercuric chloride 80.30 9-23-80 Significance of bottom material data in evaluating water quality 81.02 10-16-80 Operation and availability-- D-77 water-quality sampler 81.08 2-10-81 Electrodes for pH measurement in low-conductivity waters 81.11 5-08-81 New tables of dissolved oxygen saturation values 82.01 10-27-81 Collecting water samples for stable isotope analysis 82.05 12-11-81 Provisional method for carbonate, dissolved; bicarbonate, dissolved; and carbonate alkalinity, dissolved; electrometric titration, incremental, field 82.06 1-22-82 Policy on publishing constituents with both field and laboratory values 84.04 11-30-83 Technical information: briefing paper on mercury 84.18 9-28-84 Preservation and shipment of water samples for determination of mercury 87.03 2-12-87 pH measurement in low conductivity waters 90.01 10-03-89 Sample preservation and ampoule disposal 90.07 2-02-90 Contamination from D-77 sampler equipped with solenoid-actuated valves 91.01 10-29-90 "Methods for collection and analysis of aquatic biological and microbiological samples," by L.J. Britton and P.E. Greeson, editors, Techniques Water-Resources Investigations (TWRI), Book 5, Chapter A4 91.02 12-05-90 "Methods for collection and processing of surface-water and bed-material samples for physical and chemical analysis," by Janice R. Ward and C. Albert Harr, editors, Open-File Report 90-140 91.04 2-08-91 Office of Water Quality electronic memorandum system 91.08 8-07-91 "A primer on sediment-trace element chemistry" (second edition), by Arthur J. Horowitz 91.09 8-27-91 "Filtration of water-sediment samples for determination of organic compounds," by Mark W. Sandstrom 91.10 9-30-91 Dissolved trace element data 92.01 12-20-91 Distilled/deionized water for District operations 92.02 12-20-91 Field preparation of containers for aqueous samples 92.04 3-20-92 Revised statement regarding dissolved trace-element data production 92.05 3-20-92 Quality of existing dissolved trace-element data 92.06 3-20-92 Report of committee on sample shipping integrity and cost 92.08 3-27-92 Nutrient sample size reduction 92.10 7-13-92 Phosphorus methods and the quality of phosphorus data 92.11 7-16-92 Return of spent mercury and dichromate ampoules to the National Water Quality Laboratory 92.12 7-17-92 Trace-element concentrations in deionized water processed through selected surface-water samplers: Study results and implications 92.13 7-17-92 Trace-element contamination: Findings of studies on the cleaning of membrane filters and filtration systems 93.01 10-05-92 National Water-Quality Networks: Fiscal year 1993--October 1, 1992 to September 30, 1993 93.03 10-29-92 Dissolved trace-element data 93.04 12-02-92 Discontinuation of the NWQL determinations for "total" nitrite, "total" nitrite plus nitrate, "total" ammonia, and "total" orthophosphate (using the four-channel analyzer) 93.05 1-21-93 Evaluation of capsule filters 93.06 2-19-93 Trace-element contamination--Findings of study on the cleaning of sampler caps, nozzles, bottles, and bags for trace-element work at the part-per-billion level 93.09 4-16-93 Sample splitting devices 93.10 4-91-93 (1) Disposal of petri dishes containing bacteria media, and (2) aspergillus 93.11 7-15-93 Implementation of the protocol for collecting and processing surface-water samples for low-level inorganic analyses 94.02 11-22-93 Discontinuance of field use of mercury liquid-in-glass thermometers 94.06 1- 3-94 New custom analysis schedule (172) for blanks 94.09 1-28-94 Revision of new Division protocol for collecting and processing surface-water samples for low-level inorganic analyses 94.12 4-20-94 Changes in schedule 172 94.13 4-21-94 Evaluation of the churn splitter for inclusion in the Division protocol for the collection and processing of surface-water samples for subsequent determination of trace elements, nutrients, and major ions in filtered water 94.16 8- 5-94 New preservation techniques for nutrient samples Additional References Barnes, Ivan, 1964, Field measurement of alkalinity and pH: U.S. Geological Survey Water-Supply Paper 1535-H, 17 p. Britton, L.J., and Greeson, P.E., eds, 1989, Methods for collection and analysis of aquatic biological and microbiological samples: U.S. Geological Survey Techniques of Water Resources Investigations, book 5, chap. A4, 363 p. Busenberg, Eurybiades, and Plummer, L.N., 1987, pH measurement of low-conductivity waters: U.S. Geological Survey Water-Resources Investigations Report 87-4060, 22 p. Edwards, T.K., and Glysson, G.D., 1988, Field methods for measurement of fluvial sediment: U.S. Geological Survey Open-File Report 86-531, 188 p. Guy, H.P., and Norman, V.M., 1970, Field methods for measurement of fluvial sediment: U.S. Geological Survey Techniques of Water Resources Investigations, book 3, chap. C2, 59 p. Hem, J.D., 1985, Study and interpretation of chemical characteristics of natural water: U.S. Geological Survey Water-Supply Paper 2254, 263 p. Stevens, H.H., Jr., Ficke, J.F., and Smoot, G.F., 1975, Water temperature--influential factors, field measurement, and data presentation: U.S. Geological Survey Techniques of Water Resources Investigations, book 1, chap. D1, 65 p. Sylvester, M.A., Kister, L.R., and Garrett, W.B.,eds, 1990, Guidelines for the collection, treatment, and analysis of water samples--U.S. Geological Survey Western Region field manual: U.S. Geological Survey, Western Region, internal report, 144 p. Ward, J.R., and Harr, C.A., eds, 1990, Methods for collection and processing of surface-water and bed-material samples for physical and chemical analyses: U.S. Geological Survey Open-File Report 90-140, 71 p. Wells, F.C., Gibbons, W.J., and Dorsey, M.E., 1990, Guidelines for collection and field analysis of water-quality samples from streams in Texas: U.S. Geological Survey Open-File Report 90-127, 79 p. Wood, W.W., 1976, Guidelines for collection and field analysis of ground-water samples for selected unstable constituents: U.S. Geological Survey Techniques of Water Resources Investigations, book 1, chap. D2, 24 p. Yurewicz, M.C., 1981, Incremental field titration of bicarbonate: U.S. Geological Survey Water Resources Division Bulletin, October-December 1981, (for WRD use only), p. 8-13. Collection of Representative Samples As in past years, the Office of Water Quality reminds all field personnel that the collection of a representative sample is of utmost importance. Procedures for the collection of a representative sample are well documented. As part of this effort, cross-section surveys (depth and width) of water temperature, pH, specific conductance, dissolved oxygen, and suspended sediment have been required activities at each site in the two networks. Over a period of years the data base of such data should include observations for various seasons and surface-water discharges. Cross-section surveys should include a discharge measurement so that each measured constituent can be associated with a weighted discharge value. The results of cross-section surveys should be stored in the WATSTORE/NWIS Water-Quality File. When entering such data, be sure to enter the cross section location - WATSTORE code 00009, CROSS-SECTION LOCATION, FEET FROM LEFT BANK, LOOKING DOWNSTREAM. Contamination of trace-element samples in the field has become an important issue as laboratory methods continue to improve and reporting limits are lowered. Therefore, all individuals who are collecting water-quality samples need to be aware of the importance of keeping equipment and field vehicles clean and of using proper care when collecting and handling samples. All sampling equipment is to be thoroughly cleaned (the cleaning procedures are described in detail in Appendix D of this memo). Churn splitters and other equipment are to be stored in sealed plastic bags after they are cleaned and until they are used. Sample water should be poured carefully into the churn so that the water does not come into contact with hands or the cover of the churn. The churn is to be kept covered, when water is not being added to it (or modify the churn splitter by adding a cappable funnel as described in OWQ Technical Memorandum 94.09). In order to keep dirt off the outside of the churn, and dust from getting into the churn, it should be kept in a plastic bag which is opened only to allow access to the churn for emptying the sampler bottle. The "clean hands/dirty hands" technique is suggested where the "clean hands" person wears disposable gloves and handles only the sample bottle and the "dirty hands" person handles the sampling equipment (metal part of the sampler, reel, etc.) The "clean hands" person is careful not to touch metal objects or anything that could contaminate the sample, and changes gloves whenever this type of contact occurs. Sample processing should be done inside the vehicle and away from dust and exhaust. Best results are obtained when samples are processed in a clean, metal-free chamber (a glove box or chamber built from wood and plexiglass). All bottles are to be stored in clean areas and uncapped bottles (other than the untreated bottles) should be discarded. Untreated bottles are to be rinsed with sample water (filtered water for filtered samples and unfiltered water for unfiltered samples), as described in OWQ Technical Memorandum 92.02. Disposable gloves are to be worn when handling preservatives (and changed between different types of preservatives), and when processing bacteria samples. Periods for Sample Collection The table below indicates the time periods for sample collection for stations sampled quarterly (four times per year). Sample collection frequencies for FY 1995 are shown in Appendix A. In order for the data to meet the objectives of the Benchmark program, it is important that the sampling schedule be adhered to. QUARTERLY STATIONS first sample OCTOBER-NOVEMBER-DECEMBER second sample JANUARY-FEBRUARY-MARCH third sample APRIL-MAY-JUNE fourth sample JULY-AUGUST-SEPTEMBER Use of ICP The inductively-coupled plasma (ICP) procedure is used for the analysis of selected dissolved common and trace inorganic constituents. The ICP procedure is not to be used whenever the specific conductance is greater than 2,000 uS/cm because the detection limits become greater. Schedule 177 will be used in lieu of schedule 176 whenever the specific conductance is greater than 2,000 uS/cm. Based upon historical specific conductance data for each NASQAN and HBN Station, the percentage of samples with specific conductance values equal to or greater than 2,000 uS/cm was computed and is given in Appendix A under the right-hand heading "PROBABILITY (%) THAT SPECIFIC CONDUCTANCE WILL BE EQUAL TO OR GREATER THAN 2,000 US/CM." These probabilities indicate the expected frequency of use schedule 177 will get at each site over a long period of time. Determination of specifically which schedule to request for a sample is based on the specific conductance value measured at the time of sampling. Only schedule 176 is authorized for stations with zero probability of the specific conductance exceeding 2,000 uS/cm. Because of the uncertainty involved in predicting the number of samples that will exceed 2,000 uS/cm, both schedule 176 and 177 are authorized for four uses at HBN stations where the value given in the right-hand column of Appendix A is greater than zero. The actual number of usages authorized between schedules 176 and 177 is however four, not eight. District Water-Quality Specialists have the authority and responsibility to request schedules 176 versus schedule 177. Because use of schedule 176 versus 177 is dependent solely upon the specific conductance of the sample, District Water-Quality Specialists should ensure that all field personnel are aware that a field specific conductance measurement is absolutely necessary whenever schedule 176 or 177 is to be utilized. Unique Numbers Districts are reminded that all samples (excluding suspended-sediment samples which are analyzed in District sediment laboratories for particle size and concentration) are to be sent to the U.S. Geological Survey National Water-Quality Laboratory in Arvada, CO, with appropriate National Laboratory unique numbers. Unique numbers are described in Quality of Water Branch Technical Memorandum 79.15 and can be obtained by station number through the SPN system on DCOLKA. New unique numbers are established at the beginning of the each water year and are to be used until September 30 of each water year. Personnel collecting HBN samples should keep a current listing of the unique numbers in their field folders. Any National-Networks sample processed by the National Water Quality Laboratory without a unique number will result in the analytical costs being billed to the District default account instead of the appropriate National-Networks account. Correcting such billing errors after they occur requires a memorandum to the Coordinator, National Hydrologic Benchmark Program. Analytical Services Request Form Although the unique number, date, and time are all that are required on the Analytical Services Request Form, additional information such as station name, special sampling conditions, National-Networks program (Benchmark), etc., are helpful to the National Water Quality Laboratory personnel and District personnel processing the analytical results. All information coded in the comments section of the Analytical Services Request Form is stored in the Water-Quality File. Uniform Data-Collection Program Districts are reminded of the importance to ensure that all HBN samples be analyzed for the same measurements as specified later in this memorandum. In particular, all field measurements specified have to be done for every sample. HYDROLOGIC BENCHMARK DATA COLLECTION PROGRAM Hydrologic Benchmark Network stations to be operated in FY 1996 are listed in Appendix A. Rain gages were installed at a number of stations during FY 1994. The rain gages should collect precipitation data at the same frequency as the stream gage. Changes in locations of sampling sites must be approved by the National Networks Coordinator. All HBN stations will be sampled quarterly. Schedule 1904 will no longer be used. Analysis of radiochemicals will be on a semiannual basis (1 high-flow and 1 low-flow sample). The specific conductance is likely to exceed 2,000 uS/cm at only one HBN station - the Bear Den Creek at Mandaree, ND (06332515). Therefore, this station may require schedule 177 for analysis of quarterly dissolved common and trace inorganic constituents. All other stations will require use of schedule 176 for analysis of these constituents. HBN Sampling Schedule for FY 1996 Please notify the Office of Water Quality if the District responsible for collection of samples for any HBN station has changed recently and is therefore incorrectly listed in Appendix A. Hydrologic Benchmark Network Sampling Schedule 4 per year - Field Measurements: Instantaneous discharge (WATSTORE Code 0006l) Specific conductance (WATSTORE Code 00095) Water temperature, degrees C (WATSTORE Code 00010) Barometric pressure, mm Hg (WATSTORE Code 00025) pH (WATSTORE Code 00400) Carbonate, water, dissolved, mg/L (WATSTORE Code 00452) Bicarbonate, water, dissolved, mg/L (WATSTORE Code 00453) Alkalinity, water, dissolved, as CaCO3, mg/L (WATSTORE Code 39086) Hydroxide, water, dissolved, mg/L (WATSTORE Code 71834) Dissolved oxygen (WATSTORE 00300) Fecal coliform bacteria, 0.7 um (WATSTORE Code 31625) Fecal streptococcal bacteria, 0.45 um (WATSTORE Code 31673) 4 per year - Suspended sediment: Concentration (WATSTORE Code 80154) Percent finer than 0.062 mm, sieve diameter (WATSTORE Code 70331) 4 per year - Nutrients, lab schedule 86 4 per year - Physical properties, common and trace dissolved inorganic constituents: lab schedule 176 2 per year - Radiochemicals, lab schedule 1703 Cross-section surveys (depth and width) of temperature, pH, specific conductance, dissolved oxygen, and suspended-sediment concentration as needed to document cross-section homogeneity. If any information in this memorandum prompts questions or comments, please call Kathy Fitzgerald whose current number is (703) 648-6902. Janice R. Ward for David A. Rickert Attachments This memorandum supersedes OWQ Technical Memorandum 95.01. Distribution: A, B, S, FO, PO Key Words: water quality, networks, sampling, Benchmark, FY 1996 APPENDIX A This appendix contains the listing by District of all HBN stations. Copies of the appendix may be retrieved via anonymous ftp by issuing the following commands: ftp 126.96.36.199 login: anonymous password: your userid cd pub/benchmark type binary get appendix.a.96.fm/ bye This is a Framemaker 4.0 file. It must be opened in Framemaker to be printed. Choose the landscape option for printing. APPENDIX B NUTRIENTS SCHEDULE 86 WN OWNER:NQ COST: 77.80 CALCULATED LAB WATSTORE CODE CODE INCLUDED PARAMETERS 1688 00625 A NITR. NH4+ORG AS N WWR 1685 00666 B PHOSPHORUS, DIS. JKA 1686 00665 B PHOSPHORUS, TOTAL JKA 0160 00613 B NITR DIS NO2 AS N 0162 00671 B PHOS DIS ORTHO AS P 0301 00608 B NITR DISS NH4 AS N 0228 00631 B NITR DIS NO2+NO3 -N REQUIRES 0125 ml OF FCC 0125 ml OF RCC RADIOCHEMICALS SCHEDULE 1703 WR OWNER:NQ COST: 305.00 FIXED LAB WATSTORE CODE CODE INCLUDED PARAMETERS 0794 09511 B RADIUM-226, DISS. RN 1386 22703 E U.DIS,EXT,LIP,FF REQUIRES 0002 liters OF FAR PHYSICAL PROPERTIES, COMMON AND TRACE DISSOLVED INORGANIC CONSTITUENTS SCHEDULE 176 WI OWNER:NQ COST: 256.30 FIXED LAB WATSTORE CODE CODE INCLUDED PARAMETERS 0027 70300 A ROE, DISS. AT 180 C 0050 00076 A TURBIDITY (NTU) 0054 00935 B POTASSIUM, DISSOLVED 0068 00403 A PH (LABORATORY) 0069 90095 A SP. CONDUCTANCE LAB 0070 90410 A ALK TOT LAB. CACO3 0087 01145 A SELENIUM, DISSOLVED 0641 01005 C BARIUM, DISSOLVED 0644 01035 C COBALT, DISSOLV. 0645 01046 D IRON, DISSOLV. 0648 01056 C MANGANESE, DISSOLVED 0649 01060 A MOLYBDENUM, DISS. 0652 01080 B STRONTIUM, DISSOLVED 0653 01085 B VANADIUM, DISSOLVED 0659 00915 D CALCIUM, DISSOLVED 0663 00925 C MAGNESIUM, DISSOLVED 0664 01130 B LITHIUM, DISSOLVED 0667 00955 D SILICA, DISSOLVED 0675 00930 C SODIUM, DISSOLVED 1284 01106 E ALUMINUM-DIS-DCP 1552 01075 F SILVER GFAA DIS 1562 01065 F NICKEL GFAA DIS 1571 00940 J CHLORIDE DIS IC 1572 00945 G SULFATE DIS IC 1573 00950 E FLUORIDE DIS IC REQUIRES 0250 ml OF FA 0250 ml OF RU 0125 ml OF LC0050 0500 ml OF FU SCHEDULE 177 WI OWNER:NQ COST: 318.40 CALCULATED LAB WATSTORE CODE CODE INCLUDED PARAMETERS 0007 01005 B BARIUM, DIS. 0012 00915 C CALCIUM, DISSOLV. 0027 70300 A ROE, DISS. AT 180 C 0039 01130 A LITHIUM, DISSOLV. 0040 00925 B MAGNESIUM, DISSOLV. 0042 01056 A MANGANESE, DISSOLV. 0050 00076 A TURBIDITY (NTU) 0054 00935 B POTASSIUM, DISSOLVED 0056 00955 C SILICA, DIS. 0059 00930 B SODIUM, DIS. 0062 01080 A STRONTIUM, DIS. 0068 00403 A PH (LABORATORY) 0069 90095 A SP. CONDUCTANCE LAB 0070 90410 A ALK TOT LAB. CACO3 0087 01145 A SELENIUM, DISSOLVED 0110 01060 B MOLYBDENUM, DISSOLV. 0172 01046 C IRON, DIS. 1210 01085 D VANADIUM, DIS. AUTO. 1284 01106 E ALUMINUM-DIS-DCP 1552 01075 F SILVER GFAA DIS 1556 01035 F COBALT GFAA DIS 1562 01065 F NICKEL GFAA DIS 1571 00940 J CHLORIDE DIS IC 1572 00945 G SULFATE DIS IC 1573 00950 E FLUORIDE DIS IC REQUIRES 0500 ml OF FA 0250 ml OF RU 0125 ml OF LC0050 0500 ml OF FU APPENDIX C ALKALINITY - INCREMENTAL TITRATION METHOD Hach Titrator INTRODUCTION Alkalinity is a measure of the buffering capacity of water against acid. Degasification, precipitation, and other chemical and physical reactions may cause the concentrations of carbonate and bicarbonate to change substantially within several hours or even minutes after sample collection. Consequently, field values for carbonate and bicarbonate or alkalinity usually are more reliable than values obtained in the laboratory (Wells and others, 1990). Particulates can take up some strong acid by dissolution, adsorption, or ion exchange and, thereby, cause anomalously high measurements. For this reason, filtration through a 0.45 micron pore-size filter is required. In order to prevent contamination by wind-borne dust and loss of carbon dioxide due to warming by the sun, the analysis should be done in an enclosed vehicle (OWQ Technical Memorandum 82.05). APPARATUS 1. pH meter with combination pH probe or equivalent. 2. Hach digital titrator. 3. Titrant acid cartridges (0.16 and 1.6 N) with straight- or bent-tube delivery tubes. (NOTE: Clear delivery tubes are now available from Ocala) 4. Magnetic stirrer. 5. Deionized water. 6. 50 mL and 100-mL volumetric pipets. METHOD 1. Select the appropriate strength titrant, 0.1600 Normal (N) or 1.600N sulfuric acid, and sample volume from the following table, based on the expected alkalinity. Record the acid normality and sample volume on the field sheet. Expected Alkalinity Sample Volume Acid Normality <20 100 0.1600 20-50 50 0.1600 50-150 100 1.600 >150 50 1.600 NOTE: The volumes and acid normalities in the above table are guidelines only. Inflection points will be better defined by using the 0.1600 N acid. 2. Assemble the digital titrator: a) Insert the appropriate cartridge into the titrator and turning it 1/4 turn to lock it in position. b) Remove the vinyl cap and insert a delivery tube into the cartridge tip. Delivery tubes cannot be interchanged between different normality cartridges and should be identified to avoid cross-contamination. c) Flush the tube by turning the delivery knob to release some of the titrant into a waste container. Make sure that a sufficient amount is released to assure that there are no bubbles or water in the tube. d) Gently blot any droplets that adhere to the end of the tube and set the digital counter reading to ZERO. 3. Use a clean volumetric pipet or cylinder, rinse with sample water, and measure the appropriate sample volume into a clean beaker containing a Teflon-coated stirring bar. 4. Place rinsed pH probe (previously rinsed with sample water) into the sample and place the beaker on a magnetic stirrer. 5. Turn on stirrer and adjust stirring rate to LOW. Sample should be GENTLY stirred throughout the titration. Turn on pH meter, allow reading to stabilize and then read and record the initial pH value. 6. If sample pH is less than 8.3, then skip the next step (7). 7. If sample pH is greater than 8.3, add sulfuric acid by small increments (1 to 3 digital counts at a time) until the pH is less than 8.0. The tip of the delivery tube should be below the sample surface (keep the tube clean to avoid contamination of the sample). Allow 15-20 seconds for equilibration between incremental additions of acid. Record pH and digital counter reading after each addition of acid. 8. Titrate rapidly to pH 5.0 (5.5 for alkalinities of <20 mg/L). The tip of the delivery tube should be below the sample surface (keep the tube clean to avoid contamination of the sample). Allow 15-20 seconds for equilibration and record the digital counter reading. 9. From pH 5.0 (5.5) to 4.0, add acid by small increments (1 to 3 digital units at a time). Allow 15-20 seconds for equilibration between incremental additions of acid and record pH and digital counter reading after each addition of acid. 10. Calculations: (initial calculations should be done in the field) (a) Calculate the change in pH and the change in counter numbers and record these values on the field sheet. (b) Divide each change in pH by the change in the counter numbers and record the results on the field sheet. (c) The endpoints are the counter numbers where the maximum rates of change in pH per counter number increments occur. If a tie for the end point occurs, choose the last one (the one with the lower pH). (d) Calculate carbonate (00452). CO3 (mg/L as CO3) = A x F1/mL sample (e) Calculate bicarbonate (00453). HCO3 (mg/L as HCO3) = [B - 2(A)] x F2/mL sample (f) Calculate total alkalinity (39086). Total Alkalinity = B x F3/mL sample where: A = digital count from initial pH to endpoint near 8.3 B = digital count from initial pH to endpoint near 4.5 0.1600N 1.600N F1 12.0 120 F2 12.2 122 F3 10.0 100 After completing the titration, remove the cartridge from the titrator and replace the vinyl cap immediately to avoid exposure of the contents to the air. Rinse the delivery tube with distilled water and blow out the remaining water with a syringe to avoid starting the next titration with water. Store the delivery tubes in a clean plastic bag. REPORTING Report total alkalinity, carbonate, and bicarbonate concentrations as follows: less than 1,000 mg/L, to whole numbers; 1,000 mg/L and above, three significant figures. REFERENCES Barnes, Ivan, 1964, Field measurement of alkalinity and pH: U.S. Geological Survey Water-Supply Paper 1535-H, 17 p. Quality Water Service Unit, 1990, Water-quality field techniques: U.S. Geological Survey, Florida District, internal document, 164 p. Sylvester, M.A., Kister, L.R., and Garrett, W.B., eds, 1990, Guidelines for the collection, treatment, and analysis of water samples--U.S. Geological Survey Western Region field manual: U.S. Geological Survey, Western Region, internal document, 144 p. Wells, F.C., Gibbons, W.J., and Dorsey, M.E., 1990, Guidelines for collection and field analysis of water-quality samples from streams in Texas: U.S. Geological Survey Open-File Report 90-127, 79p. Branch of Water Quality Technical Memorandum 82.05: December 11, 1981.