Klamath Basin Water Crisis
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own property, and caretake our wildlife and natural resources.
September 5, 2003
Klamath Basin Rangeland Trust
Response to comments provided by the USGS
KBRT responses are embedded within the original document. The responses are indicated by green italicized font.
Review of Water Quality Sections of the Klamath Basin Rangeland Trust
- WY 2002 Pilot Project Monitoring Report and
- WY 2003 Pilot Project Monitoring Plan Draft
Klamath Basin Rangeland Trust, June 27, 2003
Thank you for the opportunity to review the KBRT 2002 Monitoring Report and Draft Plan for 2003. Ongoing restoration in the Wood River Valley – such as increasing in-stream flows by reducing irrigation, and decreasing the effects of grazing by lowering cattle densities and improving riparian areas with fences and plantings – can only improve conditions in the basin and in Agency Lake downstream. Both the Monitoring Report and the Monitoring Plan read well, the objectives were clearly stated and results were clearly presented. I have suggested some alternative interpretations of the data in some cases, especially with respect to evaluating potential land use effects on water quality. The data that are currently being collected, along with the additional data collection that is suggested in this review, should provide a good baseline for which to evaluate ongoing and future restoration efforts in the study area. A few of the sites currently being sampled for this effort are also being sampled for nutrients and field parameters by USG for a collaborative study of the Wood River Wetland with BLM. I look forward to sharing information and ideas with you regarding water quality in the basin.
US Geological Survey
(Comments are in black,questions in red, and suggested modifications in blue.)
Graham Matthews and Associates (GMA) have begun a pilot biomass study on Crooked Creek at the Root Ranch Gage. Currently two 3ft X 4ft nets are deployed at the site for biomass collection. The nets have a mesh opening of 250 microns and are deployed for an hour at a time. Due to the mesh size, the nets needs to be brushed on a continuous basis in order to keep the nets from clogging. Nets are deployed three times a day; morning, midday and in the evening. Additional nets are going to be made with a larger mesh size opening to see if they can be deployed for a longer period of time. We also agree that system wide surveys of the distribution and density of macrophytes and periphyton would provide a valuable addition to our baseline surveys. However, at this point in time GMA is funding the pilot biomass study outside of the budget of KBRT. If additional money should become available, we will continue the collection of biomass and add macrophyte and periphyton surveys to the KBRT monitoring program. Any information that you have on the collection of biomass would be of great use to us.
Field methods employed were, for the most part, appropriate to meet the stated objectives. In most cases, standard USGS protocols were used for sample collection, including depth- and width-integrated sampling where feasible. Further, improvements in sampling technique were used, such as using a van Dorn sampler (samples composited with a churn splitter) to capture drifting algal biomass when present. Although this method might be better at sampling aggregations of algae and decaying organic matter,punctuated episodes of algal sloughing also may be missed given the current sampling frequency. Event-triggered autosamplers (co-located with existing continuous data sites) could potentially capture such events.
If additional funding becomes available, we agree that autosamplers would be a very useful tool in evaluating punctuated episodes of algal sloughing.
We have several in-situ instruments installed throughout the Wood River Valley (Crooked Cr. at Root Ranch, Wood River at Dike Rd., Sevenmile Canal at Dike Rd, and Fourmile Canal at the Lower Weir) that are capturing diel variations in the physical water quality parameters that you have mentioned above. It would be very useful to do these at all sites where physical water quality parameters are sampled but at this time, due to budget constraints, it is not possible.
We agree with you and have found that the Quanta’s’ are not the best instrument to use, especially for turbidity measurements. We have slowly been replacing the Quanta’s with YSI 6820 Sondes which we have found are more reliable and field serviceable. All in-situ water quality instruments are "changed out" every two weeks with freshly calibrated instruments. Water quality instruments that are going to be used for a day of sampling at multiple sites are calibrated the morning before they go into the field and then each morning after, if being used for multiple days. A summary of the calibration procedure follows: Instruments are calibrated (at an elevation similar to sampling sites) in the office and then brought into the field. Before the in-situ instrument is replaced with a freshly calibrated instrument, two sets of readings are taken; one set of readings is taken from the instrument that is currently installed at the site and the second set of readings is taken from the instrument that is going to be installed at the site. This allows us to detect any drift in parameters and will allow us to adjust data accordingly. To date, we have checked the Quanta data against the YSI 6820 Sonde data and have not found any appreciable differences. The YSI 6820 Sonde dissolved oxygen parameter does stabilize much faster; field crews have been made aware of this fact and have been instructed to allow the dissolved oxygen parameter on the Quanta time to stabilize. Currently, we are not checking the dissolved oxygen reading with the Winkler Titration Method, but this could be incorporated into the procedures in the future. We will discuss this issue with Jacob Kann of Aquatic Ecosystem Sciences, LLC (AES).
All SRP samples were filtered prior to analysis. This will be made clear in the text.
This will be corrected, these samples were not acidified. We also will incorporate some QA checks on field vs. laboratory filtering occurring within 24 hours. Detection limit is listed as 0.010 mg/L for EPA Method 350.1 (Nitrogen, Ammonia. Method 350.1 (Colorimetric, Automated, Phenate).
Noted: we will incorporate equipment blanks. Unless prevented by shipping problems (which happened only rarely) , samples arrived at the laboratory within 24 hours. These samples were shipped in a dark cooler on ice. Processing of SRP, ammonia and nitrate-nitrite began immediately. Samples for total P and N were held according to standard methods.
We agree with the usefulness of measuring these additional constituents. At this point they are beyond the scope of our initial survey and of our budget.
Specific Comments on the Water Quality Component:
WY 2002 Pilot Project Monitoring Report
p. viii, second bullet.. It is stated that based on the flow balance that no irrigation diversions occurred in the lower portion of Crooked Creek. While this may be true, ground water inputs (6-8 cfs) were found in the upstream reach, and could also be occurring in the lower reach. If this is true, then such inputs of ground water would mask potential irrigation withdrawals. The fact that SRP concentrations in Crooked Creek also steadily increased in both July and September (fig. 6-1) might be another indication that ground water is entering.
The 6-8 cfs that was found to be entering in the upper reach is most likely Fort Creek water that is being returned to Creek via the Hawkins-Owens Property. There is a ditch along Hwy 62 that is bypassing water this year into Crooked Creek. Discharge measurements in this ditch will help us determine exactly what is occurring in the upper reach of Crooked Creek. The flow balance on Crooked Crook was a tool we used to determine if we had ground water inputs or unaccounted for surface water inflow in the pilot project area. KBRT has full access to both the Thomas and Root Properties (lower reach of Crooked Creek) and we are certain that no irrigation occurred on those properties.
p. ix, last bullet.. see p. 26-27 below
p. x, first bullet.. the most likely source of particulate P is from erosion that results from grazing. While this may be true, another potentially important source of particulate phosphorus, especially in this system, is sloughed algae.Does erosion include manure?
Yes, in the context stated, effects include runoff containing manure, direct manure input to the streams, and soil erosion due to vegetation removal and exposed soil.
p. 2, end of first paragraph…could reduce the anthropogenic phosphorus load to Agency Lake from the Wood River Valley by as much as 75%1. (Although a footnote is listed, none is given. This is a strong statement that might be justified by data or information in the footnote, but it’s not there)
The footnote appeared on page 1 of the document due to a formatting error in MSWord. However, the document cited was not intended to be a technical document, but instead to provide a very general overview of the KBRT project proposal. The 75% reduction is based solely on "best professional judgment" about the effectiveness of KBRT’s proposed land use changes at improving water quality conditions. For example, the total P load from the Wood River and Sevenmile systems cited in the TMDL’s is 51.7 metric tons, and 40% of that, or 20.7 metric tons, is estimated to be from anthropogenic sources. Based on conservative cattle stocking rates for the Wood River Valley, 200 metric tons of P is excreted onto the ground surface in manure. If we assume that 10% of the P in the manure reaches the water bodies, that would indicate an input of 20 metric tons from cattle. Since the KBRT management program reduces stocking rates by 80%, this would suggest a net P reduction of 16 metric tons, or 77% of the anthropogenic load. The assumption that 10% of the P in the manure reaches the surrounding water bodies is purely an assumption, and not based directly on experimental data. However, additional activities that KBRT is undertaking such as excluding cattle from riparian zones, restoring riparian vegetation, restoring wetlands, and eliminating flood irrigation, are also expecting to reduce P loading to Agency Lake from the Wood River Valley. These restoration activities aren’t accounted for in the manure loading calculations. As a result, we feel that the estimate of a 75% reduction in P loading due to the KBRT land management changes is an appropriate and conservative estimate. However, the inclusion of this number in the more technical annual report is inappropriate and an editorial oversight. If the number is utilized in the future, additional material and documentation will be provided.
Section 6 – Water Quality Monitoring
p. 23, first paragraphaddition to soil and nutrients, bacteria associated with cattle also can contribute to water quality problems such as low dissolved oxygen levels. Pilot sampling for bacteria (e.g., E. coli and fecal coliform) at a few locations could be used to identify whether this is an issue or not. Bacteria data might exist already, I don’t know.
No bacterial data exist as far as we know. We are unaware of literature showing that cattle derived bacteria contribute to low DO. We would appreciate any information on this subject, and as the budget allows we may incorporate sampling for this constituent.
p. 24.. 1) High pH (ca 9.0 units) also can damage brook trout gill lamellae (possibly other salmonids too); 2) Observation: During 2002 sampling occurred late during the season (started in July). I’d suggest that sampling begin in April or early May at the latest. Just this year (2003), I observed a long (6 foot) bright green streamer of filamentous algae (probably Cladophora) at the mouth of Wood River (WRDIKE). By June, however, it was brown and nearly gone; 3) Incorporating longitudinal measures of conductance and temperature in synoptic fashion (i.e., Lagrangian sampling) could identify or confirm dramatic changes in water quality due to changes in land use or from inputs of nutrient-rich ground water. Artesian well water in the area is rich in both SRP and ammonia (~6 mg/L).
GMA is currently conducting longitudinal or Lagrangian sampling as part of the water quality measurements that are being made every two weeks. The Crooked Creek, Wood River, and Sevenmile systems are all sampled in a longitudinal manner. Sampling this year did take place throughout the winter and spring months.
p. 25, last sentence..it states that the van Dorn sampler was used when high algal biomass was visible. When and at what sites was this observed? I’m glad that your sampling includes this aspect. This fraction is often missed.
In general, the van Dorn sampler is being used at any site where the field crew can visibly see material that will not pass through the nozzle of the DH-48. Sites include but are not necessarily limited to the following: Annie Cr. above the Wood, Crooked Cr. at Root Ranch, Crooked Creek below Ranch Creek (formerly Crooked Creek above the Wood River), Wood River at Dike Rd, Sevenmile Canal at Dike Rd., West Canal above Sevenmile Canal, Sevenmile Canal above below West Canal, and Fourmile Canal at the Lower Weir. Several sets of samples have been taken with both the DH-48 and the van Dorn sampler in order to compare the two techniques. We plan on doing more of this in the future as well.
p. 26-27 ..It is stated that phosphorus concentrations increased in the Wood River, Sevenmile Creek, and Annie Creeks in response to land use (grazing induced erosion). While this may be true, the biggest increases in phosphorus occurred at the mouth sites at the Wood River Wetland dike, where water chemistry can be influenced by Agency Lake. The authors acknowledge this, and have installed Doppler velocity gages at these sites. Further, the steady downstream increase in SRP, especially in the Wood River Basin, also may reflect inputs of phosphorus-rich groundwater. Also,couldn’t the increase in particulate P also come from manure?
Upon PRELIMINARY review of the Doppler velocity data from the Wood River at Dike Rd gaging station there is no indication that the flow ever reverses, therefore it seems reasonable that lake water chemistry is not affecting water quality measurements at this site. The flows at Sevenmile Canal at Dike Rd. do reverse on a regular basis and will be taken into account when doing water quality analysis. Flows have never been observed reversing on Annie Creek above the Wood and there is no reason to suspect that they would. Particulate P could certainly be increased by manure as well.
The potential for additional inputs from phosphorous-rich groundwater was not evaluated in the 2002 study, but will be incorporated in 2003 based on data collected at the irrigation test plot.
p. 27..end of third full paragraph ..although return flow from Annie Creek probably increases the nutrient load downstream in Sevenmile Canal,sampling Sevenmile upstream from the dike road (at the Wood River Wetland inlet, for example) might avoid influence from Agency Lake, although this site also may be affected.
GMA has added several sampling locations in the Sevenmile system. Sampling has begun on Sevenmile Canal above West Canal, West Canal above Sevenmile Canal, and Sevenmile Canal below West Canal. These sites should give us a much better picture of the inputs in the Sevenmile system.
p. 27 last paragraph ..According to fig. 6-5 other sites also exceeded 12.8 deg. C, the temperature standard for salmonid bearing streams (Westside Cascades). Is the standard higher here?
The standard here is also 12.8 deg. C. We will correct this in future reporting of temperature data from these other systems.
p. 28 second full paragraph..significant warming in this reach".. Warming here also could also be due to the effect of Agency Lake, as mentioned above, but also to the relatively high concentration of dissolved organic carbon in this reach. The stained water efficiently absorbs heat, producing unusually high temperature at the surface compared with the bottom.
Comment noted GMA and AES will discuss this further.
p. 28 under pH …Was alkalinity measured? It might help explain why pH fluctuations were dampened at WRDIKE. It could also have been the time of year (periphyton can peak in the early spring). High pH (ca 9.0 units) also can damage brook trout gill lamellae (possibly other salmonids too).
GMA has never measured alkalinity; GMA and AES will discuss this further.
p. 28 under DO ..Contrary to many studies that target mid-summer for diel pH and DO measurements, the water quality effects of periphyton photosynthesis can be highest during early spring, when flows just start to decline. At this time, light is becoming increasingly available, water velocities (nutrient delivery rates) are higher, and alkalinity is relatively low (allows for greater change in pH). In 2003, the greatest fluctuation in pH (and DO) in another western stream (Clackamas River) occurred in mid-May. The effects of photosynthesis on pH and DO, however, began in March). The pH and DO fluctuations declined sharply, following a period of algal sloughing. Recent data (June 2003) suggest that we’re beginning another period of algal growth and accrual, as fluctuations are again on the rise (but not as sharply as in May).
Comment noted. GMA began water quality sampling much earlier in the 2003 sampling season than during the 2002 pilot project sampling season.
Section 7 – Biological Monitoring
p. 35 third paragraph ..with respect to the "reference reach" sampled for invertebrates.. with the majority of benthic invertebrates consisting of amphipods, chironomids, and oligochaetes, this doesn’t sound like a reference stream.The 9% EPT at this site (9% mayflies) -- were they mostly Baetid mayflies? These are also tolerant. The benthic invertebrate work might be improved by including woody debris as an additional substrate type to be sampled. In many systems, submerged woody debris is the richest habitat for both invertebrates and algae. In some cases, overhanging vegetation also may be the richest habitat for invertebrates. In general, depositional habitats are much less diverse. Were the chironomids identified to species? Given the massive biomass (clouds) of midges in this area, getting this level of identification might better distinguish reference site condition from impacted sites, especially if depositional areas continue to be the only habitat sampled for invertebrates.
You are correct in that this is not a true reference reach or stream. This is old nomenclature, and was derived from the comparison of a non-restored reach with a restored reach (a Crooked Creek restoration project that reduced stream width by 1/3). So it is only a reference reach with respect to the restoration project and not in the sense of an unimpaired reach. It is clearly impaired by past grazing practices. Yes, the majority were Baetid mayflies, as you note these can also be pollution tolerant, and this is consistent with the fact that this is not a true reference reach in the standard sense. This will be clarified in future reporting. We are willing to incorporate woody debris, although this is not very prevalent in Crooked Creek. We are very interested in any methodology you may have for sampling woody substrate. Chironomids were not identified to species.
Section 8 – Vegetation Monitoring
p. 36, fifth paragraph .. I don’t have fig. 8-1 (Not in list of figures, not in .pdf files of text or figures)
Figure 8-1 was accidentally omitted from the report.
Comments on the Figures
figs. 4-2 and 4-3 ..the date format is incorrect (on my copy).
When the file was converted to PDF, the number format did not transfer correctly. More review of the PDF’s will be conducted before the 2003 report is released.
figs. 6-1, 6-2 ..1) I’d prefer to see the various components of N in separate plots, instead of combining them into TN. Actually, I’m not sure what TN, NH4, NO3 represents. The persulfate TN includes all N in the sample, so it’s confusing that ammonia and nitrate are also listed on the axis label. Might the black bars represent both forms of inorganic N and SRP? Can you label the plots as such? Again, I’d prefer to see the N plots separated, in order to help sort out potential N sources or transformations, such as nitrification; 2) The sampling dates portrayed are confusing. Although sampling occurred on 7/24, it looks like it was done over a week-long period; 3) I like the downstream trending bars, but TESP is a spring, and takes away from longitudinal pattern. Can you change TESP from a bar to a symbol? 4) Where there’s large variations among sites (e.g., TN and TP, fig. 6-1 and fig. 6-2) I’d suggest noting scale differences somewhere on the plot, its quite large in some cases; 5) In some cases, it looks like sites were cut off (TP concentration for ACAW and SMFS in fig.6-1); 6) Having some indication on the plot as to whether irrigation was occurring would make a nice addition.
These helpful suggestions for clarification are noted and we will incorporate them into future reporting. The legend was inadvertently left off of the figures; this will be corrected.
figs. 6-3, 6-4 1) For consistency with fig. 6-1 and 6-2, include the 2 sites where loads weren’t calculated (WR62 and WRLR), so that their position matches that for the concentration data figs.
figs. 6-5 through 6-8 ..the data that went into the field parameter plots are all instantaneous measurements. While this is noted in the text, it should also be pointed out in the figures.
fig. 6-6 ..the downward trend in pH in the Wood River may be due to increased heterotrophic activity, in response to higher levels of dissolved organic carbon or some other factor.
fig. 6-9 ..fig caption change to July to Nov (fig. 6-9), to July – Nov (fig. 6-10 and 6-12).
fig. 6-14 ..is there any confirmation, such as flow data from the Doppler unit at WRDIKE, that might confirm whether data collected at this site was truly Wood River water, not Agency Lake water?
PRELIMINARY review of the Doppler record from the Wood River at Dike Rd gaging site indicates that the site never reverses flow and therefore is Wood River Water.
WY 2003 Pilot Project Monitoring Plan Draft
p. 3 fourth paragraph..Report states that Wood River at Dixon and Weed Roads have been kept in operation. Two paragraphs previous, however, it states that these gages were continued until 1996-97.
USBR operated Wood River at Dixon Rd until 1996. GMA continued to operate the gage on the Wood River at Dixon Road however there are some missing data due to datalogger failure and download failure. USBR operated a gage on the Wood River at Weed road until 1997. GMA continued to operate a gage at this location. GMA will re-word this paragraph to make this point clear.
p. 4.. on meeting Objective 2 (quantifying tailwater) ..is a tall objective. How many weirs can you conceivably install?
It is impossible to quantify all of the tailwater entering stream channels in the Wood River Basin. However, a great deal of tailwater can be measured in return flow ditches using discharge measurements, standard pressure transducer gaging stations, weirs, or using acoustic Doppler equipment. Further streamflow accounting units can be used to quantify the amount of tailwater entering stream channels. Streamflow accounting units have been set up on Crooked Creek as well as on Sevenmile Creek. There is one flood irrigated pasture on the Popson property where an intense effort is being made by Damion Ciotti (Graduate Student, OSU) to perform a surface and ground water "budget". His study will help in determining the scale to which tailwater can be quantified.
Comment on fig. 3-1..Expand site labels for the Sevenmile Creek sites (presently, the Sevenmile Creek at Sevenmile Road is not labeled as such.
p. 7 second paragraph ..Why not include Mares Egg spring? The name implies blue-green algae like this water, which might mean its high in phosphorus. Is it?
Mares Egg Spring currently has been monitored on a small scale this year for discharge. Currently, GMA is looking at the water quality budget to determine if it is possible to take one or two sets of water quality measurements on all of the source springs in the project area.
Section 5 – Water Quality
*Most of the comments for this section are elaborated upon in the General Comments section above
p. 21..near the bottom ..on the use of bi-weekly.. restate as "every two weeks"
p. 22.. under turbidity samples ..If you have to reduce the amount of sampling, retain storm sampling if possible.
Storm sampling will be retained.
p. 23 ..under continuous monitoring..I suggest increasing the frequency of continuous measurements for diel parameters up to a maximum of 30 minutes between samples. Although hourly data is good, 30-min readings, especially for temperature, DO, and pH would be better. Also, consider adding chlorophyll a as an additional parameter to be measured continuously.
GMA will discuss with AES the benefits of logging samples at a 30 minute intervals. Depending on budgetary constraints in future years it may be possible to add chlorophyll a as an additional water quality parameter. GMA and AES will discuss this as well.
p. 24 second paragraph..in addition to the point QA checks with the NIST thermometer at the continuous monitor, do cross sectional and local longitudinal temperature measurements to ensure the monitor is located in a representative area. With all the ground water inputs and local surface warming (especially in areas with high dissolved organic carbon), there could be considerable local variations in water temperature.
GMA will include longitudinal and cross-sectional measurements of temperature at stations with thermographs and where physical water quality parameters are not collected with the Quanta or YSI 6820 Sonde. Currently, at sites that are sampled with the Quanta or YSI 6820 Sonde cross-sectional and depth integrated samples of temperature and physical water quality parameters are being made. We believe the USGS rule of thumb is that this needs to be done a minimum of three times a year at a station to insure that cross-sectional variability is known. GMA is currently doing this every two weeks. We will also include longitudinal analysis at these sites to determine the variability.
p. 24 nutrient sampling procedures.. I like the use of the van Dorn to capture coarse particulate organic matter, but certain particulars, such as how samples will be filtered, are not included. You’re reporting SRP, so I’m assuming you did filter the samples. Also, I see that the lab does native sample spikes and replicates, and that 10% of samples also will be true field replicates. This level of QA seems appropriate, given the good QA seen from the lab during 2002. In addition to these QA samples, I would suggest adding both equipment blanks and laboratory blanks (bottle blank to check lab, not equipment) for nutrients, and if the standard reference samples are not already being submitted blindly, I would do so. I suggest including reference samples that are representative of the entire data set, especially to verify accuracy of low level NO3 and NH4 values. I didn’t see QA results for such samples.
Equipment is rinsed with native sample water before each sample is collected. Sample bottles are one time use bottles and are not re-used by GMA or the lab. Replicates and Duplicates are being sent to the lab blindly so that there is no possibility of time correlation or site correlation on the labs part. We will look into the possibility of obtaining reference samples.
Section 6 – Geomorphic and Habitat Monitoring
General comment: with the potential to increase the amount of woody debris in these streams through restoration,it would be good to including sampling the wood for benthic invertebrates.
Noted; can you provide us sampling protocol for sampling woody debris?
p. 27..Do the aerial surveys include the Wood River Wetland? If so, I’m interested
There are a number of sets of aerial photographs of the Wood River wetland in recent years. The best contact is Wedge Watkins at BLM Klamath Falls.
p. 30..longitudinal profiles of water depth/chemistry also may be obtained using a small Doppler unit/hydrolab that can be towed with a kayak.
Such longitudinal profiles of water depth and chemistry can be made in this fashion, but at this time, it is beyond the scope of this project.
Section 7 – Biological Monitoring
*Most of the comments for this section are elaborated upon in the General Comments section above
p. 34..requiring that pools be 6 feet deep seems to be a stringent requirement. Trout like pools much less deep than 6 feet, especially if there’s some form of cover.
We actually surveyed all pools in each reach, not only those greater than 6’. We will clarify this.
p. 35 ..see comments above on sampling woody debris and overhanging vegetation for invertebrates
Again, we would much appreciate methods for both of these.
B-3, top table ..shows that nitrate + nitrite samples can be acidified and held for 28 days (as mentioned in the General Comments section, this may be in error). Holding nutrient samples for this long may give inaccurate values.What were the actual holding times? (they are not reported in either document). Also, NH4 samples are analyzed with EPA method 350.1, which includes preservation with sulfuric acid and isolation with distillation in boric acid. Was this actually done? (DEQ doesn’t do it as part of their typical protocol, and they also use the EPA 350.1 method).
Similar to DEQ, acidification and distillation with boric acid was not performed. Samples arrived at the laboratory generally within 24 hours, and processing began at that time.
B-7, calibration procedures..look good, except that it states that periodic recalibrations will be performed. I would suggest that daily calibrations for dissolved oxygen (DO), pH, conductivity, and turbidity be done on all instruments (making sure to bracket the observed values). Also, recheck the DO at each site and recalibrating as necessary, particularly if elevation is much different from where it was last calibrated. For continuous monitors, pay close attention to fouling. Typically, only our most pristine sites can go more than 2 weeks without cleaning. Also, I would re-calibrate, even if the values are within 10-15%. Also, see comments about using Quanta Hydrolabs in the General Comments section.
With the number of stations being operated, it is not possible to calibrate in-situ instruments on a daily basis. Water quality instruments that are brought into the field to collect samples at locations where no in-situ instruments are installed are installed on a daily basis. It would be nice to re-calibrate DO at each site but in our opinion this would be time prohibitive with the number of sites that need to be sampled in a day. Currently we don’t believe that there is enough change in barometric pressure between sites to warrant re-calibration on a site to site basis. GMA and AES will look into this further. All in-situ instruments are calibrated every two weeks and they are always re-calibrated even if the values fall within 10-15%.
B-7, cross-sectional measurements..also evaluate local longitudinal variations in field parameters, including potential variations with depth (especially where high levels of dissolved organic carbon occur).
See response to comments on p.24 second paragraph above.
C-14, disposal of formazine..this is a known carcinogen and should be disposed of as hazardous waste, not down the drain.
Turbidity monitoring at continuously operated sites has been discontinued due to the poor performance of the Quanta turbidimeter. Calibrations of the turbidimeters that are used to analyze turbidity for the turbidity samples collected with the DH-48 are performed at the GMA lab where all regulations for the disposal of hazardous chemicals are followed.
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