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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Prepared by Division of Water Surface Water Section Monitoring Unit 1110 W. Washington Street Phoenix, Arizona 85007 Lin Lawson, Editor Contributors Lee Johnson Jason Jones Doug McCarty Kyle Palmer Steven Pawlowski Sam Rector Patti Spindler Roland Williams
The Arizona Department of Environmental Quality shall preserve, protect and enhance the environment and public health, and shall be a leader in the development of public policy to maintain and improve the quality of Arizona's air, land and water resources.
Printed on recycled paper
Publication Number OFR-07-04
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________ ACKNOWLEDGEMENTS This report could not have been written without the hard work and dedication of the following ADEQ staff who worked on the field crews in the heat of the summer and in the cold rains of winter: Roland Williams, Lee Johnson, Doug McCarty, Kyle Palmer, Sam Rector, Patti Spindler, Susan Fitch, Amanda Fawley, Jennifer Hickman, Jason Sutter, Steve Pawlowski, Marty Schlein, and Andy Salmon. This report would not have been written without the work of Lin Lawson, our editor-in-chief. We'd like to express our thanks to Ms. Emma Benanati, research coordinator at the Grand Canyon National Park Research Office for her assistance in obtaining the necessary Scientific Research and Collecting Permit for this research and for her help on the river. A special thanks goes to Dr. Joseph Shannon, Merriam-Powell Center for Education and Research, at Northern Arizona University for the logistical support, technical advice, and his skills as a professional boatman and river trip leader. It simply would not have been possible to conduct this research without his assistance and leadership. This research was funded by the Arizona Department of Environmental Quality. We are grateful to ADEQ management for approving the funding for this data collection effort. A special thanks goes to Karen Smith, former Director of the Water Quality Division and Linda Taunt, current Deputy Director of the Water Quality Division for their support for this project.
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________ EXECUTIVE SUMMARY The water quality of 17 Colorado River tributaries within Grand Canyon National Park was sampled quarterly from July 2004 through May 2005. Water sample analyses included nutrients, inorganics, suspended sediment concentration, turbidity, Escherichia coli bacteria, total and dissolved metals and trace metals. The water quality of 16 of the tributaries is considered to be good with few exceedences of the state's water quality standards. An exceedence of the Human Health standard for arsenic occurred once at Crystal Creek. Selenium occurred infrequently with no exceedences of water quality standards. Trace metal sampling revealed three exceedences of the Human Health standard for lead; once at Kanab Creek and twice at the Paria River. There were no exceedences for copper and mercury. Nutrient levels at all sites were generally low except for the Paria River which had high concentrations of phosphorus and organic nitrogen. Suspended sediment fractions were related to rim origin and distance from source water. The Paria River consistently had high turbidity measurements. The presence of E. coli bacteria was minimal and within normal background levels at all tributaries except for the Paria River which had consistently high colony counts and exceedences of the acute and chronic E. coli water quality standards. Loadings of selected parameters at all sample sites were calculated to determine loading contributions to the Colorado River. The Paria River is contributing sizable and sometimes substantial amounts of arsenic, selenium, copper, lead, mercury, nitrogen, phosphorus, total suspended sediments, and E. coli bacteria. Macroinvertebrates were sampled in the spring of 2005 from 13 sites in 12 of the tributaries. However, the samples were classified as "compromised" due to natural flooding conditions at time of sampling and are considered unacceptable for 305(b)/303(d) assessments and listing purposes. Results presented in the report are for informational purposes only. Data revealed that all but one tributary had low macroinvertebrate Index of Biological Integrity scores which cannot be related to water quality but did validate flooding disturbance.
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Page Acknowledgements...................................................................................................................... iii Executive Summary ..................................................................................................................... iv Table of Contents...........................................................................................................................1 Tables.............................................................................................................................................2 Figures............................................................................................................................................3 Appendices.....................................................................................................................................4 Introduction....................................................................................................................................5 Purpose and Scope ...................................................................................................................5 Sampling Design......................................................................................................................6 Sampling sites ..........................................................................................................................6 Sampling Duration and Frequency ..........................................................................................8 Target analytes .........................................................................................................................9 Sample Methods...........................................................................................................................10 Water Quality of Grand Canyon Tributaries ...............................................................................11 Water Types ? Ionic Composition .........................................................................................12 Arizona Water Quality Standards ..........................................................................................15 Ambient Surface Water Metals..............................................................................................15 Arsenic (As) .....................................................................................................................15 Selenium (Se)...................................................................................................................20 Trace Metal Sampling ? Copper, Lead, and Mercury .....................................................22 Copper (Cu) ...............................................................................................................23 Lead (Pb)....................................................................................................................24 Mercury (Hg) .............................................................................................................25 Conclusions ? Trace Metals.......................................................................................27 Nutrients.................................................................................................................................29 Suspended Sediment Concentration (SSC)............................................................................35 Turbidity ................................................................................................................................38 Bacteria ..................................................................................................................................41 Results..............................................................................................................................41 Conclusions......................................................................................................................42 Bioassessments and Habitat Assessments of Colorado River Tributary Streams .......................43 Background ............................................................................................................................43 Methods and Study Area........................................................................................................44 Overall Bioassessment Results ..............................................................................................45 Geographic Analysis of Biological Results ...........................................................................49 North and South Rim Stream Comparisons...........................................................................50 Other Patterns in the Data ......................................................................................................51 Habitat Results .......................................................................................................................51 Conclusions............................................................................................................................52 Literature Cited ............................................................................................................................54
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Page Table 1. Grand Canyon Tributary Sampling Sites........................................................................8 Table 2. Target Analytes...............................................................................................................9 Table 3. Measured parameters and Method Reporting Limits (MRL) .......................................11 Table 4. Arsenic concentrations at sites having values at or above the Method Reporting Limit ....... 17 Table 5. Sample day total arsenic loadings as pounds per day...................................................20 Table 6. Occurrence of selenium at sample sites by date ...........................................................21 Table 7. Mean selenium loadings at sites having concentration values above the MRL ...........22 Table 8. Estimated annual dissolved mercury loading being contributed to the Colorado River........... 29 Table 9. Mean nitrogen and phosphorus concentrations ............................................................31 Table 10. Nutrient loadings on Grand Canyon tributaries..........................................................33 Table 11a. Typical daily TKN loadings......................................................................................34 Table 11b. Typical daily total nitrite plus nitrate loadings .........................................................34 Table 11c. Typical daily total phosphorus loadings ...................................................................35 Table 12. Fine and Coarse Suspended Sediment Fraction concentrations by site......................36 Table 13. Daily Suspended Sediment Concentration loadings at sample sites with and without flood flows ......................................................................................................................39 Table 14. Creeks having the highest suspended sediment loadings per square mile of watershed area..............................................................................................................................39 Table 15. Bacteria samples exceeding 100 cfu/100 ml...............................................................41 Table 16. Effects of flow and rain on E. coli colony counts at Bright Angel Creek ..................42 Table 17. Macroinvertebrate Index of Biological Integrity thresholds for wadeable, perennial streams of Arizona .......................................................................................................43 Table 18. ADEQ Macroinvertebrate sample collection history at Colorado River tributary stream sites, 1992-2006 ...............................................................................................................45 Table 19. Bioassessment scores for Colorado River tributary streams sampled in May 2005 ..........46 Table 20. Warm water macroinvertebrate metric values for Colorado River tributary streams sampled in May 2005......................................................................................................48
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________ LIST OF FIGURES Page Figure 1. Location of monitoring sites with ADEQ site codes......................................................7 Figure 2. Stiff diagrams of bicarbonate waters............................................................................13 Figure 3. Stiff diagrams of sulfate and mixed ionic waters .........................................................14 Figure 4. A compilation of National Park Service data on the occurrence of total arsenic in tributaries to the Colorado River in the Grand canyon, 1992-1994.............................................19 Figure 5. Mean arsenic loadings in pounds per day.....................................................................19 Figure 6. Estimated annual dissolved copper loadings for the seventeen sampled tributaries to the Colorado River...................................................................................................................24 Figure 7. Estimated annual dissolved lead loadings for the seventeen sampled tributaries to the Colorado River.......................................................................................................................25 Figure 8. Dissolved mercury concentrations as nanograms per liter by site and date .................26 Figure 9a. Dissolved mercury loadings, as pounds per sample by sample date for each tributary...28 Figure 9b. Dissolved mercury loadings, as pounds per sample by sample date for each tributary...28 Figure 9c. Dissolved mercury loadings, as pounds per sample by sample date for each tributary...29 Figure 10. Comparison of mean nutrient concentrations among sample sites ............................32 Figure 11. Percentages of Coarse and Fine Fractions of Suspended Sediment at Grand Canyon tributary sites ..................................................................................................................37 Figure 12. Turbidity as NTU by site and date .............................................................................40 Figure 13. Comparison of 2005 and historic macroinvertebrate IBI Scores ...............................46 Figure 14. Relative importance of 9 macroinvertebrate metrics in 13 Colorado River tributary sites sampled in May 2005...........................................................................................................47 Figure 15. Correlation between drainage area and warm water IBI Score, May 2005..................................49 Figure 16. Correlation between drainage area and warm water IBI score, 1992-1997 ...............49
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Page Appendix A: Site Codes and Sample Site Locations...................................................................55 Appendix B: Arizona Designated Uses of Grand Canyon Sampled Streams..............................56 Appendix C: Summary and Raw Data Tables of Ultra-Clean Metals Analysis for Copper (Cu), Lead (Pb) and Mercury (Hg) .............................................................................................57 Appendix D: E. coli Occurrence by Site and Date ......................................................................65 Appendix E: Macroinvertebrate Taxa Collected from 12 Grand Canyon Tributaries.................67 Appendix F: Macroinvertebrate Metric and Index of Biological Integrity Scores for ADEQ/NPS samples collected 1992-2006..................................................................................................................... 74 Appendix G: Sample Site Habitat Assessment Data ...................................................................76
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Purpose and Scope
The Arizona Department of Environmental Quality (ADEQ) is responsible for implementing a water quality monitoring program for rivers and streams in Arizona. Arizona Revised Statute ?49-225 mandates that ADEQ conduct ongoing monitoring of the waters of the state to: ? Detect the presence of pollutants ? Determine compliance with applicable water quality standards ? Determine effectiveness of best management practices and best available demonstrated control technologies ? Evaluate the effects of pollutants on public health or the environment, and ? Determine water quality trends (A.R.S. ?49-225). The Clean Water Act (1972), its amendments, and Section 106 requires that states implement water quality monitoring programs to monitor, compile and analyze data on the quality of the waters of the United States and to support water quality assessments of surface waters required under ?305(b) of the Clean Water Act. Under this Act, ADEQ must conduct a comprehensive assessment of the water quality of the state's surface waters every two years. This section of the Act requires ADEQ to categorize each surface water as to whether existing water quality is impaired or adequate to support attainment of the water body's designated uses. In some cases, there is not enough data or the data is incomplete to make a water quality assessment. ADEQ places such surface waters on a water quality monitoring planning list and targets them for follow-up monitoring to obtain the necessary data to fill the data gaps. One of ADEQ's primary objectives in monitoring water quality in major tributaries of the Colorado River in the Grand Canyon was to obtain a sufficient amount of credible data to assess water quality for the ?305(b) water quality assessment report. Water quality data obtained by the Grand Canyon water quality investigation is presented here and summarized in the 2006 Integrated Report titled: 2006 Status of Ambient Surface Water Quality in Arizona ? Arizona's Integrated 305(b) Assessment and 303(d) Listing Report (ADEQ (Draft), 2007). The importance of the Colorado River to Arizona was a significant factor in sampling the Grand Canyon tributaries. The water from the Colorado is used extensively for agriculture, drinking water, and industrial uses and a significant portion of the water flows to Phoenix and Tucson via the Central Arizona Project Canal. Specific objectives for ADEQ monitoring of Grand Canyon tributaries were to: ? Collect water quality data to characterize baseline water quality conditions in tributaries to the Colorado River ? Determine compliance with applicable surface water quality standards ? Obtain credible data for use in the ?305(b) water quality assessment report ? Collect biological data on the attributes of the benthic macroinvertebrate communities in the tributary streams to assess their biological integrity, and ? Collect E. coli bacteria data to assess the microbiological water quality of tributary streams.
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ______________________________________________________________________________
Sampling Design
ADEQ water quality monitoring program organizes its ambient water quality monitoring activities according to a 5-year rotating basin schedule. ADEQ has identified 10 river basins in Arizona for purposes of organizing data collection by the water quality monitoring program. ADEQ monitors water quality in rivers and streams located in two basins each water year. All 10 basins in the state are scheduled for monitoring over a 5-year cycle. In Water Year 2005, ADEQ conducted water quality monitoring in the Upper Colorado River-Grand Canyon and San Pedro River basins. ADEQ used a targeted sampling design for this water quality investigation. It was not feasible or practical for ADEQ to use a probability-based sampling design or to randomly select sampling sites because of logistical and time constraints imposed by conducting water quality monitoring activities within the wilderness of the Grand Canyon.
Sampling Sites
ADEQ selected 17 sampling sites (Figure 1) on tributaries to the Colorado River in the Grand Canyon. Representative sampling sites on these tributary streams were selected using rigorous criteria. ? The tributary was reliably perennial. ADEQ did not attempt to sample springs, intermittent or ephemeral waters within the Grand Canyon. ? Sampling sites were established on reaches of tributary streams above their confluences with the Colorado River and within reasonable hiking distance from the river. In most cases, sampling sites were established within ? mile above the confluence with the Colorado River. ADEQ did not sample springs or streams that required substantial hiking up side canyons or that were flowing only above the inner gorge of the Grand Canyon because of time constraints. ? Sampling sites were established where there was reasonable and safe access by boat from the Colorado River. ? Sites were established to address existing data gaps from previous stream monitoring. ADEQ had previously obtained water quality data on Grand Canyon tributaries as part of an intensive survey conducted as part of an ADEQ/National Park Service cooperative monitoring program in 1992, 1993, and 1994. A separate water quality investigation to conduct bioassessments in Grand Canyon tributaries was conducted in 1997. The location of sampling sites (Table 1) is indicated by the alpha/numeric site code. The first two letters (CG) of the code indicates the Colorado River Basin within the Grand Canyon. The next three letters represents a code for the name of the stream and the following six digits is the channel course distance in miles from the confluence to the sample site.
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 1. Location of monitoring sites with ADEQ site codes.
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 1. Grand Canyon Tributary Sampling Sites. Sampling Site Name Location Code Paria River CG PAR 001.62 Mile 0.1a Nankoweap Creek CG NAN 000.20 Mile 52 Clear Creek CG CLE 000.19 Mile 84 Bright Angel Creek CG BRA 000.44 Mile 88 Monument Creek CG MON 000.19 Mile 93 Hermit Creek CG HRM 000.08 Mile 95 Crystal Creek CG CRY 000.05 Mile 98 Shinumo Creek CG SHI 000.05 Mile 108 Royal Arch Creek CG RYA 000.05 Mile 116 Tapeats Creek CG TAP 000.08 Mile 134 Deer Creek CG DEE 000.07 Mile 136 Kanab Creek CG KAN 000.26 Mile 143 Matkatamiba Creek CG MAT 000.03 Mile 148 Havasu Creek CG HAV 000.36 Mile 157 Spring Canyon Creek CG SPG 000.17 Mile 204 Three Springs Creek CG THS 000.04 Mile 216 Diamond Creek CGDIA 000.06 Mile 226 a ? Mile "0" is located at Lee's Ferry, Arizona, which is immediately upstream of the confluence of the Paria and the Colorado Rivers. The reference to "Mile ___" in the third column of Table 1 is the distance in river miles from the starting point at Lee's Ferry (Mile 0), Arizona, to the stream confluence of the sampled stream. For example, the sampling site on Nankoweap Creek (CG NAN 000.20) is located 0.20 mile above the confluence with the Colorado River and 52 river miles below Lee's Ferry, Arizona. Appendix A presents a full description and the exact location of each site.
Sampling Duration and Frequency
ADEQ conducted water quality monitoring for this investigation in Water Year (WY) 2005, which began on July 1, 2004 and ended on June 30, 2005. ADEQ staff conducted water quality monitoring activities on four rafting trips that took place in 2004 and 2005. Each sampling trip started at Lee's Ferry and ended at Diamond Creek, a distance of 226 river miles. Each monitoring trip took approximately two weeks to complete. The 14-day river trip duration utilized motorized rafts to minimize travel time on the river. ADEQ typically conducts quarterly monitoring of sampling sites when implementing the 5-year rotating basin monitoring program. However, because of National Park Service rules and the difficult travel conditions, ADEQ could not schedule quarterly monitoring of the tributary streams. The National Park Service prohibits the use of motorized rafts within the Grand
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Canyon from September to December each year. Therefore, the monitoring schedule required a late summer sampling trip in July and August 2004, a winter trip in January 2005, and two spring trips in March and May 2005. Bioassessments were conducted at twelve of the seventeen sampling sites during the ADEQ macroinvertebrate spring index period in May, 2005.
Target Analytes
ADEQ collected data on the same core set of chemical, physical and biological water quality indicators at each sampling site and date. The core set of target analytes represents water quality information typically gathered by most state water quality monitoring programs to characterize baseline water quality conditions. The core group includes general water chemistry (inoragnics), total and dissolved metals, nutrients, and bacteria (Table 2). Table 2. Target Analytes. G R O U P 1 - FIELD MEASUREMENTS pH Total dissolved solids Air temperature ?C Specific conductivity Stream flow Water temperature ?C Dissolved oxygen (mg/L & % Sat.) Turbidity G R O U P 2 - GENERAL CHEMISTRY pH Sulfate, total Bicarbonate Specific conductivity Fluoride, total Carbonate Calcium, total Chloride, total Alkalinity, total Magnesium, total Total dissolved solids Hardness Sodium, total Total suspended solids Potassium, total Suspended sediment concentration G R O U P 3 - NUTRIENTS Nitrogen, Ammonia (NH3-N) Nitrogen, total N02/N03 Phosphorous, total Nitrogen, Total Kjeldahl G R O U P 4 - DISSOLVED METALS Beryllium Copper Mercury Cadmium Lead Zinc G R O U P 5 - TOTAL METALS Boron Copper Cadmium Lead Chromium Manganese
Antimony Arsenic
Antimony Arsenic Beryllium
Mercury Selenium Zinc
G R O U P 6 - BACTERIA Escherichia coli (E. coli)
G R O U P 7 - BIOLOGICAL Benthic macroinvertebrates
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Representative water samples, biological samples and environmental measurements were collected using methods described in A Manual of Procedures for the Sampling of Surface Waters (Lawson, 2006). A suite of field measurements were obtained at each sampling site using a Hydrolab multiparameter probe to measure specific electrical conductance (?mhos/cm), dissolved oxygen (mg/l), percent oxygen saturation, pH (SU), water temperature (?C), and total dissolved solids (mg/l). Turbidity was measured with a portable Hach 2100P Turbidimeter. Stream velocity (ft/sec) was measured with a Marsh-McBirney flow meter and converted to discharge (cfs) from the sample site cross-section measurements. Grab water samples were collected from the undisturbed uppermost end of a sampling reach in the main flow of water. Dissolved metal samples were field filtered. Samples were chilled until delivery to the Arizona Department of Health Services, State Laboratory in Phoenix, where the designated analyses were performed. A two-set water sample was collected with specialized handling (USEPA Method 1669, Clean Sampling of Natural Waters for Trace Metals) and field processed. Samples were analyzed for dissolved lead, copper, and mercury at Albion Environmental, College Station, Texas. Duplicate and split samples were collected. Deviations from Method 1669 are permitted provided that reliable analyses of samples are obtained and that sample blanks are not contaminated. Four deviations were employed due to environmental, weather and water conditions: 1) a delayed filtration by a single person, 2) field blanks were not processed at every site, 3) at sites having high turbidity, the water samples were pumped through geofilters rather than the small capacity filters supplied by the vendor, and 4) a single container, shielded with a plastic envelope to prevent air contamination of water samples, was used during the entire trip for processing all water samples. Bacteria samples were filtered and field incubated for twenty-four hours on mTEC media and field enumerated. Bacteria samples were not processed at some sites when the sample could not pass through the membrane filter due to excessive turbidity. Macroinvertebrates were collected from a 3-minute timed kick sample with a D-frame kick net in riffles and runs. Some samples were collected during high flows although ADEQ protocols require a four week delay after high flow events. Data from these samples were not be used for bioassessments. Two sites, Tapeats Creek and Bright Angel Creek, were not sampled for macroinvertebrates due to flood flows at time of visit.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Fifty-one chemical and field parameters were measured at each site and are listed in Table 3 together with the laboratory method and the Method Reporting Limit (MRL). Sixteen tributary sites within the Grand Canyon were sampled on a single pass through schedule. The Paria River sample site, 1.6 miles upstream from its confluence with the Colorado River and reachable by road, was sampled quarterly, but on a different sampling schedule than the other Canyon streams. Table 3. Measured parameters and Method Reporting Limits (MRL). Measured Parameters Measured Parameters Inorganics Method Metals Method MRL
Alkalinity, Total (mg/L as CaCO3) Alkalinity, Phenolphthalein (mg/L) Specific Conductance (?mhos/cm @ 25?C) Hardness, Total (mg/L as CaCO3) Hardness, Ca Mg Calculated (mg/L as CaCO3) pH, Lab Solids, Total Dissolved (mg/L) SM 2320 B SM 2320 B EPA 120.1 EPA 130.2 a EPA 150.1 EPA 160.1 EPA 353.2 EPA 350.1 EPA 351.2 EPA 365.4 2.0 2.0 b 10 b 0.1 10 0.02 0.02 0.05 0.02 E. coli (Colonies/100 ml) Suspended Sediment Concentration (Gravimetric), Fine Fraction (mg/L) Suspended Sediment Concentration (Gravimetric), Coarse Fraction (mg/L) Total Suspended Solids (mg/L) Area, Cross-Section, of Stream (sq.ft.) Depth of Stream, Mean (feet) Flow, Stream, Instantaneous (cfs) Flow, Rate (ft/sec.) Oxygen, Dissolved (mg/L) Oxygen, Dissolved, Percent of Saturation pH, Field EPA 200.9 EPA 200.9 EPA 200.9 EPA 200.7 EPA 200.9 EPA 200.7 EPA 200.7 5.0 10 0.50 100 1.0 10 10 Specific Conductance, Field (umhos/cm @ 25?C) Stream Width (feet) Temperature, Water ?C Temperature, Air ?C Turbidity (NTU) Note: MRL ? Method Reporting Limit a. A calculated value b. Method Reporting Limit not applicable Copper, Dissolved (ug/L) Lead, Dissolved (ug/L) Lead, Total (ug/L) Manganese, Total (ug/L) Mercury, Total (ug/L) Mercury, Dissolved (ug/L) Mercury, Dissolved (ng/L) Selenium, Total (ug/L) Zinc, Total and Dissolved (ug/L) Biological EPA 1603 2 EPA 1638 EPA 1638 EPA 200.9 EPA 200.7 SM 3112B EPA 3112B EPA 1631e EPA 200.9 EPA 200.7
0.10 0.02 10 10 0.5 0.5 0.02 5 50
Nitrite Plus Nitrate, Total (mg/L as N) Nitrogen, Ammonia, Total (mg/L as N) Nitrogen, Kjeldahl, Total, (mg/L as N) Phosphorus, Total (mg/L as P)
Physical Measurements
BLS 256 BLS 256 EPA 160.2 5.0 5.0 4.0 b b b b b b b b b b b b
Major Ions
Bicarbonate (mg/L as HCO3) (Anion) Carbonate Ion (mg/L as CO3) (Anion) Calcium, Total (mg/L as Ca) (Cation) Chloride, Total (mg/L) (Anion) Fluoride, Total (mg/L as F) (Anion) Magnesium, Total (mg/L as Mg) (Cation) Potassium, Total mg/L as K) (Cation) Sodium, Total (mg/L as Na) (Cation) Sulfate, Total (mg/L as SO4) (Anion) a a EPA 200.7 SM 4500 CL D SM 4500 F-C EPA 200.7 EPA 200.7 EPA 200.7 EPA 300.0 b b 1.0 1.0 0.05 1.0 0.5 1.0 1.0
Field Measures
Antimony, Total and Dissolved (ug/L) Arsenic, Total and Dissolved (ug/L) Beryllium, Total and Dissolved (ug/L) Boron, Total (ug/L) Cadmium, Total and Dissolved (ug/L) Chromium, Total (ug/L) Copper, Total (ug/L)
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Water Types ? Ionic Composition
Waters can be classified by such terms as calcium-bicarbonate, magnesium-sulfate, etc. The water type represents the predominant cation and anion, expressed in milliequivalents per liter. The classifications convey general information, useful for comparison discussions, but are not precise (Hem, 1989). Four cations (sodium, potassium, calcium, magnesium) and four anions (chloride, sulfate, bicarbonate, and fluoride) were measured. Fluoride and potassium were consistently found to be minor components in the ionic balance and are not presented in the graphics. Stiff diagrams of bicarbonate and sulfate waters (Figures 2 and 3) were constructed on mean concentration values. There is a variety of water types at the seventeen streams sampled. The most common water type is calcium-bicarbonate (5 streams). Three streams are calcium-sulfate and the remaining eight streams are mixtures having three or more dominant ions. There does not appear to be any commonality of water type with other data, such as rim side origin, size of watershed, or distance from source origination. The water types are likely a reflection of the particular geologic strata associated with the water and hydrologic conditions. Relative to each other, the sum of the cations and anions, in meq/L, reveals the degree of mineralization among sampled streams. For instance, Kanab Creek (29.2 meq/L), Matkatamiba Creek (32.2), Crystal Creek (33.1) Paria River (41.1) and Monument Creek (41.7) were highly mineralized. Whereas, Tapeats Creek (6.8 meq/L), Bright Angel Creek (7.0), Deer Creek (7.5), Clear Creek (7.8) and Shinumo Creek (7.8) were the least mineralized of the seventeen streams.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 2. Stiff diagrams of bicarbonate waters. Calcium-Bicarbonate
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 3. Stiff diagrams of sulfate and mixed ionic waters. Calcium-Sulfate
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Arizona Water Quality Standards
Aquatic and Wildlife designated uses: It is the intention of the State of Arizona that the designated uses and criteria assigned to the state's surface water will provide a level of water quality fully protective of aquatic and wildlife species dependent upon it. Water quality standards for Aquatic and Wildlife designated uses are allocated by acute and chronic conditions and are of the total and dissolved forms of a specific parameter. An acute standard would be used on the results of a single grab sample. A chronic standard is applied for compliance purposes and is determined from the geometric mean of the last four samples taken at least 24hours apart (AAC, 2002). The applicable designated uses for Grand Canyon tributaries are acute and chronic Aquatic and Wildlife cold water (A&Wc) and warm water (A&Ww). The A&Wc designated use is applied to Nankoweap, Shinumo, and Tapeats Creeks. All other sampled streams have the A&Ww designated use applied to them. Human Health and Agricultural designated uses: Human Health and Agricultural ambient water quality criteria are numeric values limiting the amount of chemicals present in our nation's waters. Human Health and Agricultural criteria are developed under Section 304(a) of the Clean Water Act of 1972 and Arizona Revised Statutes, Title 18, Chapter 11. The designated uses are Domestic Water Source (DWS), Fish Consumption (FC), Full Body Contact (FBC), Partial Body Contact (PBC), Agricultural Irrigation (AgI), and Agricultural Livestock watering (AgL). Kanab Creek is the only tributary with the DWS or AgL designated use. None of the sampled Colorado River tributaries are designated AgI. Appendix B lists the designated uses for streams sampled during this investigation.
Ambient Surface Water Metals
Eight metals were sampled at stream sites for total and dissolved fractions, while four (boron, chromium, manganese, and selenium) were analyzed for the total fraction only (Table 3). "Total" refers to the concentration of metals analyzed in an unfiltered sample after vigorous digestion with nitric acid to a pH of 2 or less. "Dissolved" refers to metals in the sample that will pass through a membrane filter with a pore size of 0.45 microns. After filtration, the sample is preserved with the addition of nitric acid. Dissolved metals are biologically available and some may be toxic to aquatic organisms when at elevated levels. The toxicity of some metals in the fine fraction is hardness dependent.
Arsenic (As)
Arsenic is a metal that occurs naturally in the earth's crust. It enters natural waters through the dissolution of minerals and ores. Human activities have also introduced arsenic to water from urban runoff, pesticides, fossil fuel combustion and smelting and mining wastes. Arsenic is often found in Arizona's surface and ground waters. Odorless and virtually tasteless, arsenic concentrations are highest in areas of hydrothermal sulfide mineralization which then contribute to basin-center lake-bed deposits that may contaminate groundwater that flows through and past the clays. Many streams in the Grand Canyon receive significant contributions to flow from springs, some of which may either drain these types of alluvial deposits or may, like
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Pumpkin Spring near mile 213, receive arsenic input from thermal springs. Often, the arsenic concentration in an individual stream can vary inversely with flow, with the highest concentrations seen during periods of low flow when spring inputs make up the majority of the surface flow. While the acute toxicity of arsenic has been well documented, it is the carcinogenic potential at low concentrations that raises concern in this situation. Arsenic is categorized by the USEPA as a "class A" or demonstrated human carcinogen based on sufficient human epidemiological evidence (as opposed to animal studies). Also, increased mortality from multiple internal organ cancers (liver, kidney, lung, and bladder) and an increased incidence of skin cancer were observed in populations consuming drinking water high in inorganic arsenic" (USEPA, 1998). Unlike the risks of toxicity posed by acute or bioaccumulable pollutants, the risk posed by carcinogens is characterized by a statistical possibility of contracting cancer from any one dose of a toxicant. This risk can be increased by either increasing the individual dose (amount of toxicant) or increasing the number of administrations of any given dose over time. In lay terms, it is like tossing a die: each time you toss it, you have a one in X chance of the die landing with a specific face up. The more times the die is tossed, the more times that one in X chance is taken. While the risk posed by the arsenic concentrations found in tributaries to the Colorado River in the Grand Canyon is statistically low, it is none-the-less a definable risk. However, this risk should not be construed as a reason to refrain from drinking water from these streams in cases of dehydration. Treatment through disinfection and filtration with most commercially available filters is not efficient in removing arsenic from natural waters. The most prudent approach is to obtain, disinfect and filter water either from the main channel of the Colorado or from tributaries with lower average arsenic concentrations. Arsenic appeared in measurable quantities at five sites (Table 4). Diamond Creek was the only site at which both the total and dissolved forms were measurable for the four sample dates. Detected amounts were slightly above the MRL at Havasu and Monument Creeks. The highest concentration was found at Crystal Creek in the July 2004 sample (120 ?g/L for both total and dissolved), which exceeded the Arizona Human Health water quality standard of 50 ?g/L total arsenic. Arsenic at Havasu Creek was principally in the particulate form, whereas at the other four sites the dissolved form constituted either all or the majority of detected arsenic. Total Arsenic - Human Health Standards (?g/L)
Domestic Water Source 50 Fish Consumption 1450 Full Body Contact 50 Agriculture Livestock 200
The Human Health water quality national maximum contaminant level for arsenic is 10 ?g/L. Three of four samples taken from Crystal Creek exceeded that standard, one by a factor of 12.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Table 4. Arsenic concentrations at sites having values at or above the Method Reporting Limit.
Crystal Creek Arsenic Concentrations, ug/L
24-JUL-2004 150 100 50 05-MAY-2005 0 08-JAN-2005 Total Arsenic Dissolved Arsenic
Date 24 July 2004 8 Jan. 2005 5 March 2005
Total Arsenic ?g/L 120 30 16 ND : 10
Dissolved Arsenic, ?g/L 120 24 15 ND : 10
5 May 2005
Highlighted red numbers indicate water quality exceedence.
Diamond Creek Arsenic Concentrations, ug/L
01-A UG-2004 30 20 10 12-M A Y-2005 0 13-JA N-2005 To tal Arsenic Dis s o lv ed Arsenic
Date 1 Aug. 2004 13 Jan. 2005 11 March 2005
Total Arsenic ?g/L 21 15 15 13
Dissolved Arsenic, ?g/L 22 12 14 12
12 May 2005
Havasu Creek Arsenic Concentrations, ug/L
29-JUL-2004 15 10 5 10-MAY-2005 0 11-JAN-2005 Total Arsenic Dissolved Arsenic
Date 29 July 2004 11 Jan. 2005 8 March 2005 10 May 2005
Total Arsenic ?g/L 11 11 12
Dissolved Arsenic, ?g/L ND : 10 ND : 10 ND : 10
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Table 4. Continued.
Monument Creek Arsenic Concentrations, ug/L
24-JUL-2004 15 10 5 05-M A Y-2005 0 07-JA N-2005 To tal Arsenic Dis s o lv ed Arsenic
Date 24 July 2004 7 Jan. 2005 4 March 2005 5 May 2005
Total Arsenic ?g/L 14 15 11
Dissolved Arsenic, ?g/L 14 ND : 10 10
Paria River Arsenic Concentrations, ug/L
20-JUL-2004 30 20 10 26-A PR-2005 0 08-NOV-2004 To tal Arsenic Dis s o lv ed Arsenic
Date 20 July 2004 8 Nov. 2004 31 Jan 2005 26 Apr. 2005
Total Arsenic ?g/L 17 12 29
Dissolved Arsenic, ?g/L ND : 10 ND : 10 ND : 10
Note: The ND (non-detect) value of 10 ?g/L was used as the concentration value in the diagrams. A review of National Park Service data stored in EPA's STORET data system found that arsenic regularly occurred at high concentrations in samples from two streams within the Canyon (Figure 4). Both Lava Creek (Lava Chuar) and Crystal Creek exhibited concentrations substantially above the national drinking water MCL for arsenic. To place the concentrations of a pollutant in perspective, it is insightful to know the effective load being delivered to the receiving body of water, in this case, the Colorado River. General estimates of daily and mean annual loads of selected pollutants transported during the sampling period are used to assess relative contributions from upstream source areas. Flows were assumed to be static for the calibration period. Estimated loads were calculated for total recoverable arsenic, copper, lead, mercury, SSC, TKN, total nitrite plus nitrate, and total phosphorus. The loading formula used is: Load = 3600
sec hr lbs - water cu. ft. * 24 * 62.4 * concentration in mg/L (ppm) * flow hr day cu. ft. sec
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Loadings provide a pragmatic representation of the amount of the pollutant that flows past a point at a moment in time or the estimated amount moving past that point on an annual basis. Arsenic loading at the five sites having concentrations above the MRL is shown in Figure 5 and Table 5. When the concentration table (Table 4) is compared to the loadings table it becomes obvious that Havasu Creek and the Paria River are contributing substantial amounts of arsenic, relative to other tributaries, to the Colorado River. If the point-in-time loads are annualized, Havasu Creek is contributing approximately 1700 pounds and Paria River over 1200 pounds of total arsenic to the Colorado River, whereas Crystal Creek is contributing less than 200 pounds.
Figure 4. A compilation of National Park Service data on the occurrence of total arsenic in tributaries to the Colorado River in the Grand canyon, 1992-1994.
Dissolved Arsenic, ug/L
70 60 50 40 30 20 10 0
R . Th re eS pr in gs C r. C ry sta lC re ek C ol or ad o Pa ri a H er m it Sp rin gs Cr . W ar m C re ek C hu ar R iv er C re ek H av as u C r.
Standard = 10 ug/L
Li ttl e
Figure 5. Mean arsenic loadings in pounds per day.
Mean Arsenic Loadings, lbs/day
Havas u Creek 6 4 Monument Creek 2 0 Paria river
La va
Diamond Creek
Crys tal Creek
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 5. Sample day total arsenic loadings as pounds per day.
Sample Site/ Watershed Area Crystal Creek 44 sq.mi Diamond Creek 275 sq.mi Havasu Creek 2966 sq.mi Monument Creek 0.4 sq.mi Paria River 1410 sq.mi Sample Date
24 July 2004 8 Jan. 2005 5 March 2005 5 May 2005 1 Aug. 2004 13 Jan. 2005 11 March 2005 12 May 2005 29 July 2004 11 Jan. 2005 8 March 2005 10 May 2005 24 July 2004 7 Jan. 2005 4 March 2005 5 May 2005 20 July 2004 8 Nov. 2004 31 Jan. 2005 21 April 2005
Sample Day Loading, lbs/day
Sample Day Flow, cfs
0.04 2.4 7.7 22.34 0.8 6.6 11 4.57 70 83 81 76 0.02 0.02 0.73 0.28 32 31 34 50
Meana Loading, lbs/day 0.57b
Notes: ND represents a total arsenic concentration that was below the MRL of 10 ?g/L. a ? The mean of the sample day loadings. b - This is an estimated load. The MRL was used for the loading calculation. The actual load would have been less than the value shown. The estimated figure was retained to illustrate the relationship between flow and concentration. When the five loadings from Table 5 are plotted against watershed area, the regression plot indicates a good correlation and is significant at = 0.008; however, when all sites with non-detects are included the correlation is not significant. This may indicate that where arsenic is present in a watershed, size of watershed area and geology is the determining factor for arsenic concentration.
Regression of Arsenic Loadings vs. Watershed Area
6 5 4 3 2 1 0 0 Arsenic Loading, lbs/day
Wate r s he d Area, sq. mi.
Selenium (Se)
Selenium occurs naturally in the environment; although being widespread it is among the rarer elements on the surface of the earth. It is released through both natural processes and human activities. It is relatively immobile in soils, but contact with oxygen will transform it into a
- 20 -
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 mobile compound and easily transported in aquatic systems. In the mobile form, the chances of exposure are greatly enhanced. Selenium is an essential nutrient to the mammalian body at low levels, but is toxic at high concentrations. Humans may be exposed to selenium either through the ingestion of food or water. When selenium uptake is too high, health effects will likely arise. The seriousness of these effects depends upon the concentrations of selenium ingested and length of exposure. These health effects can be exhibited as brittle hair, deformed nails, rashes, swelling of the skin and severe body pains. Selenium poisoning may become so severe that in some cases may cause death. When animals absorb or accumulate extremely high concentrations of selenium it can cause reproductive failure and birth defects. Selenium was present in its total form, above the MRL of 5.0 ?g/L, in 16% of the water samples at seven of the seventeen sites. The A&Ww chronic standard for total selenium is 2.0 ?g/L. There were not enough samples above the MRL at any of the sample sites to compute the chronic standard. Although the chronic standard does not apply to a single sample, it is useful as a benchmark comparison. All measurable occurrences of selenium were above the chronic standard in the eleven water samples (Table 6). Estimated selenium loadings to the Colorado River (Table 7) reveal that Paria River is contributing a more substantial amount than other measured tributaries. Deer Creek contributes approximately one hundred pounds a year, while the other five streams, that had concentrations above the MRL, contribute very little over the course of a year.
Table 6. Occurrence of selenium at sample sites by date. Site Name
Deer Creek Hermit Creek Matkatamiba Creek Matkatamiba Creek Matkatamiba Creek Monument Creek Monument Creek Paria River Royal Arch Creek Royal Arch Creek Three Springs Creek
27-Jul-2004 05-Mar-2005 10-Jan-2005 07-Mar-2005 09-May-2005 04-Mar-2005 05-May-2005 26-Apr-2005 25-Jul-2004 06-May-2005 10-Mar-2005
Total Selenium, ?g/L
10 5.4 6.1 6.7 5.6 6.7 5.5 14 6.0 5.1 6.3
16 14 12 10 8 6 4 2 0
Occurrence of total selenium by date and location.
ug /L
7 /27 /2 00 4
1 /10 /2 00 5
4 /26 /2 00 5
7 /25 /2 00 5
Deer Hermit Cr. Cr.
Matkatamiba Cr.
Monument Paria Royal Arch Three Cr. R. Cr. Springs Cr.
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3 /10 /2 00 5
3 / 5 /2 0 0 5
5 / 9 /2 0 0 5
3 / 7 /2 0 0 5
5 / 5 /2 0 0 5
3 / 4 /2 0 0 5
5 / 4 /2 0 0 4
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 7. Mean selenium loadings at sites having concentration values above the MRL.
Site Name Paria R. Deer Cr. Hermit Cr. Monument Cr (a). Matkatamiba Cr. (b) Three Springs Cr. Royal Arch Cr. (a) Mean lbs/day 3.8 0.33 0.05 0.02 0.02 0.02 0.01 Mean lbs/yr 1344 117 18 6 6 6 4
Note: (a) Mean based on two samples (b) Mean based on three samples
Trace Metal Sampling ? Copper, Lead, and Mercury
Ultra-Clean Trace Metal Sampling, also referred to as Clean Hands Sampling, is a term commonly applied to EPA Method 1669, a protocol developed by the U. S. Environmental Protection Agency to sample metals that have been deemed toxic at low levels in ambient waters. An explanation of the ADEQ protocol is found in A Manual of Procedures for the Sampling of Surface Waters (Lawson, 2006). The ADEQ protocol is based on Method 1669: Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels (www.epa.gov). For this study, dissolved copper, lead, and mercury were the target analytes. The Ultra-Clean protocol requires a near absolute control of the sample processing environment to prevent surface or air-borne contamination. The employment of a processing tent in the field ensured a clean environment that guarded against air-borne contamination from the strong dust laden canyon winds. A deviation from the documented protocol was required when filtering extremely turbid waters. Instead of the small 0.45 micron pore filter supplied by the contract laboratory, a larger 0.45 micron pore groundwater filter capsule was utilized. Field blanks and duplicate samples were collected at sites predetermined by the trip leader. Typically the sampling team would perform five field blanks and two field duplicates during the course of a sampling trip. Some sample sites do not have a full compliment of four sample results for some analytes. An accident at the analyzing laboratory damaged sample bottles for 5 field grabs and 1 field blank from the May 2005 sampling run, rendering them unfit for analysis. The sample sites affected were Clear Creek, Diamond Creek, Nankoweap Creek, Shinumo Creek, and Tapeats Creek. Ultra-Clean samples were not collected from the Paria River site for 8 November 2004 and 2 May 2005. Method detection limits at the contract laboratory were: Copper 0.10 ?g/L, Lead 0.02 ?g/L, and Mercury 0.20 ng/L [?g/L = micrograms per liter (parts per billion) and ng/L = nanograms per liter (parts per trillion)]. A dissolved mercury sample collected on 4 March 2005 at Monument Creek produced a result of 12.7 ng/L (0.0127 ?g/L), which is below A&Ww standard of 2.4 ?g/L. When compared to other Grand Canyon tributary sites and years of water samples taken throughout the state, the 12.7 ng/L dissolved mercury value is unusually high. A field blank or duplicate was not taken to confirm suspected contamination, therefore the value is considered valid but questionable.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Acute and chronic Aquatic and Wildlife designated uses for copper and lead are not fixed numbers, but vary with hardness measurements. The acute standard for dissolved mercury, Aquatic and Wildlife warm and cold water, is 2.4 ?g/L. The Aquatic and Wildlife warm and cold water dissolved mercury chronic standard is 0.01 ?g/L (AAC, 2002). Appendix C presents a summary of the dissolved copper, lead, and mercury data.
Copper (Cu)
Copper is an essential element, aiding in human, animal, and plant metabolism. However, the ingestion of excessive copper can be problematic. Ingested doses of copper, up to 100 mg, can result in severe digestive irregularities. In surface water copper can travel great distances, either suspended on sediment particles or as free ions. Levels of copper in fresh water and salt water have been found to be generally low. In the United States, studies of raw, untreated surface water have shown copper content ranging from 0.001 mg/L to 0.28 mg/L with a national mean of 0.015 mg/L. Sixty-five samples recorded a dissolved copper value greater than the MRL. Paria River had the highest recorded concentration at 0.00318 mg/L, well below the national mean of 0.015 mg/L. The Human Health and Agricultural water quality standard is of the total form. The lowest standard is 500 ?g/L for Agricultural Livestock watering and there were no exceedences of that standard. The Aquatic and Wildlife acute and chronic water quality standard for copper is of the dissolved form and there were no exceedences at any of the sample sites. The acute and chronic standard is dependent upon the hardness value at time of sampling. The most stringent standard is for chronic A&Ww and A&Wc and is 2.74 ?g/L at a hardness of 65 mg/L. The lowest hardness recorded at any one sample site was 89 mg/L hardness at Clear Creek. The measured dissolved copper was 0.711 ?g/L and the water quality standard for this case is 8.11 ?g/L, thus there were no hardness values that could have resulted in an exceedence of the 2.74 ?g/L standard. The Arizona water quality standard for total copper (total recoverable) is 1300 ?g/L for DWS, FBC, and PBC, and 500 ?g/L for Agricultural Livestock. There were no exceedences of these standards. Estimated annual copper loadings, Figure 6, reveal that the Paria River is contributing approximately 500 pounds dissolved copper to the Colorado River. Tapeats and Kanab Creeks are discharging over a hundred pounds a year while Monument, Spring Canyon, and Three Springs Creeks are contributing negligible amounts. Streams contributing two pounds or less include Hermit Creek, Matkatamiba Creek, Monument Creek, Spring Canyon Creek, and Three Springs Creek.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 6. Estimated annual dissolved copper loadings for the seventeen sampled tributaries to the Colorado River.
Lead (Pb)
Lead is a toxic substance and has adverse effects on human and animal health. Low levels in drinking water, when continuously ingested, will cause deterioration in health. High concentrations in the body can cause death or permanent damage to the central nervous system, the brain and kidneys. Lead can bioaccumulate throughout an entire food chain. Thirty-three samples recorded a dissolved lead value greater than the MRL. The Aquatic and Wildlife chronic and acute water quality standard for lead is of the dissolved form and there were no exceedences at any of the sample sites. The standard is dependent upon the hardness value at time of sampling. The most stringent standard is for A&Ww and A&Wc and is 0.54 ?g/L at 65 mg/L hardness. There were five samples that had dissolved lead concentrations greater than 0.54 ?g/L (0.00054 mg/L), but the hardness for those samples far exceeded the hardness value at the specific dissolved lead concentration that would have provided a numerical chronic or acute standard. The Human Health total lead water quality standard for DWS, FBC, and PBC is 15 ?g/L. One sample at Kanab Creek and two samples at Paria River exceeded that amount. The remaining samples at those streams were below the MRL of 5.0 ?g/L.
Sample Site Kanab Creek Paria River Paria River Sample Date 28 July 2004 20 July 2004 31 January 2005 Total Lead Concentration, ?g/L 28 75 66
Estimated annual dissolved lead loadings (Figure 7) reveal that the Paria River is discharging approximately two hundred pounds to the Colorado River. This amount is more than four times
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 that being contributed by Havasu Creek which is discharging the next highest estimated amount at forty-six pounds. Streams contributing one pound or less include Deer Creek, Hermit Creek, Matkatamiba Creek, Monument Creek, Nankoweap Creek, Royal Arch Creek, Spring Canyon Creek, and Three Springs Creek.
Figure 7. Estimated annual dissolved lead loadings for the seventeen sampled tributaries to the Colorado River.
Mercury (Hg)
Mercury is a well known and naturally occurring environmental pollutant, but human activities also release significant amounts to the environment that accumulate on land surfaces, in waterbodies, and in plant and animal life. Human health concerns arise when fish and wildlife from these contaminated ecosystems are consumed by humans. High levels of mercury can lead to a wide range of physical ills, such as kidney and neurological damage, fatigue, vision problems, and tremors. Consequently, Arizona waterbodies and aquatic life tissue are regularly monitored for mercury. Dissolved mercury occurred at each of the seventeen tributary sample sites, when measured to parts per trillion (Figure 8). The most stringent chronic water quality standard (0.01 ?g/L or 10 ng/L) for dissolved mercury are for the A&Wc and A&Ww designated uses. There were no exceedences of that standard. One sample (12.7 ng/L; 0.0127 ?g/L) at Monument Creek (March 2005) exceeded 10 ng/L; however the chronic standard does not apply to one grab sample. The Human Health Fish Consumption designated use water quality standard for total mercury is 0.6 ?g/L. There were no recorded concentrations above the MRL of 0.5 ?g/L and thus there were no exceedences of the total standard. There was a small difference between north and south rims streams carrying dissolved mercury. North rim streams had an average of 1.0 ng/L whereas south rim streams had an average of 0.6 ng/L.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 8. Dissolved mercury concentrations as nanograms per liter by site and date. Bright Angel Creek Clear Creek* Crystal Creek
Deer Creek
Diamond Creek
Havasu Creek
Hermit Creek
Kanab Creek
Matkatamiba Creek
Monument Creek
Nankoweap Creek*
Paria River
Royal Arch Creek
Shinumo Creek*
Spring Canyon Creek
Tapeats Creek*
Three Springs Creek
Note: * indicates a missing data point due to broken bottle
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figures 9a, 9b, and 9c present dissolved mercury loadings, as pounds per sample by date for each tributary. Bright Angel Creek recorded the highest loading (3.8 lbs/day) in the March 2005 sample. Kanab Creek recorded the second highest (0.79 lbs/day) in the January 2005 sample and Paria River recorded 0.5 and 0.7 lbs/day in the July 2004 and the January 2005 samples, respectively.
Dissolved mercury loadings were annualized (Table 8) based on sample day mean loading. When ranked in descending order, Bright Angel Creek is estimated to be contributing approximately 500 pounds of dissolved mercury to the Colorado River. Insignificant amounts are being contributed by Matkatamiba, Spring Canyon, Hermit, and Three Springs Creeks. In total, approximately 1200 pounds of dissolved mercury is being discharged annually into the main stem river from the seventeen sampled tributaries.
Conclusions ? Trace Metals
Neither acute nor chronic Aquatic and Wildlife water quality standards were exceeded for dissolved copper, lead or mercury. Three exceedences were recorded for total lead for the Human Health designated uses DWS, FBC, and PBC. Dissolved copper was detected above the MRL in nearly every sample. Dissolved mercury was detected in measurable amounts in two-thirds of the samples, and dissolved lead in one-half of the samples. The majority of Grand Canyon tributaries have small to medium sized watersheds that have few anthropomorphic impacts, other than recreational uses such as hiking and camping. The presence of dissolved metals in these remote hydrologic systems would appear to be related to the geological strata through which the system flows and the ability of the system to maintain that metal in a dissolved state.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 9a. Dissolved mercury loadings, as pounds per sample by sample date for each tributary.
1000 900 800 700 600 500 400 300 200 100 0
lbs Hg/day
Figure 9b. Dissolved mercury loadings, as pounds per sample by sample date for each tributary.
1000 900 800 700 600 500 400 300 200 100 0
lbs Hg/day
7/24 /04 1/7/0 5 3/5/0 5 5/5/0 5 M ean 7/28 /04 1/10 /05 3/7/0 5 5/9/0 5 M ean 7/28 /04 1/10 /05 3/7/0 5 5/9/0 5 M ean 1/7/0 5 3/4/0 5 5/5/0 5 M ean 1/5/0 5 Hermit Creek Kan ab Creek M atkatamib a M o n u men t Nan Creek Creek ko weap
- 28 -
7/20 /04 1/31 /05 M ean Paria Riv er
1 /7/05 3 /4/05 5 /3/05 M e an 7 /22/0 4 1 /6/05 3 /3/05 M e an 7 /24/0 4 1 /8/05 3 /5/05 5 /5/05 M e an 1 /9/05 3 /7/05 5 /7/05 M e an 8 /1/04 1 /13/0 5 3 /11/0 5 M e an 7 /29/0 4 1 /11/0 4 3 /8/05 5 /10/0 5 M e an Brig h t A n g el Cr. Clear Creek Cry s tal Creek Deer Creek Diamo n d Creek Hav as u Creek
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 9c. Dissolved mercury loadings, as pounds per sample by sample date for each tributary.
1000 900 800 700 600 500 400 300 200 100 0 7/25/05 1/8/05 3/6/05 5/6/05 1/8/05 3/3/05 1/12/05 1/9/05 3/6/05 7/31/04 1/12/05 3/10/05 5/11/05 M ean M ean M ean M ean
lbs Hg/day
Roy al Arch Creek
Shinumo Creek
Sp ring Cany on
T ap eat s Creek
T hree Springs Creek
Table 8. Estimated annual dissolved mercury loading being contributed to the Colorado River.
Site Name Bright Angel Cr. Paria River Kanab Creek Havasu Creek Tapeats Creek Shinumo Creek lbs/yr 500 230 130 125 110 55 Site Name Crystal Creek Nankoweap Creek Monument Creek Diamond Creek Royal Arch Creek Deer Creek lbs/yr 40 7 6 6 5 4 Site Name Clear Creek Matkatamiba Creek Spring Canyon Creek Hermit Creek Three Springs Creek lbs/yr 3 1 1 1 <1
Nutrients are chemical elements critical to the development of plant and animal life. In healthy streams, nutrients in moderate amounts are required for the growth of algae that form the base of a complex food web supporting the entire aquatic ecosystem. The most common nutrients in streams are forms of nitrogen and phosphorus. When nutrients are abundant, algae and aquatic plants will grow excessively and multiply well beyond the amount needed to support the food web. When the excess growth dies, microorganisms break it down, consuming dissolved oxygen from the water. Dissolved oxygen can be completely consumed in the decomposition process. The typical result is death to most if not all aquatic organisms dependant upon oxygen for life processes. Nutrients measured were ammonia nitrogen (NH3), nitrite (NO2) plus nitrate (NO3), Total Kjeldahl Nitrogen (TKN), and phosphorus. Ammonia nitrogen was detected above the MRL (0.02 mg/L) at six of the sites. Those values never exceeded 0.024 ?g/L. Since this nitrogen species is a minor component of the combined nutrients it will not be further discussed. TKN is a measure of organic N and free ammonia. Since ammonia concentrations were near or below MRLs, the TKN measurements were predominantly composed of organic N. Table 9 and Figure 10 presents a comparison of mean concentrations of TKN, NO2+ NO3, and phosphorus. - 29 -
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Configurations of minimal phosphorus (Figure 10) and TKN as compared to greater amounts of NO2+ NO3 are the most common configurations among sites, with the exceptions of Clear Creek, Shinumo Creek, and Paria River. The two creeks had higher concentrations of TKN than NO2+N. There is a significant difference between Paria River and all the creek sample sites. This river site had approximately four times the amount of phosphorus as the other sites and considerable higher TKN and NO2+ NO3 than most of the creeks. It is suspected that upstream agricultural sources, and possibly recreation, are responsible for the higher concentrations since phosphorus is the limiting nutrient in unimpaired Arizona surface waters. There are no nutrient water quality standards that apply to any of the sampled Grand Canyon tributary streams and thus compliance of water quality standards is not an issue.
Table 10 presents nutrient loadings with (n=4) and without flood flows (n=3). The n=3 loading represents the most likely daily and annual loading to the Colorado River while the n=4 loading likely represents a maximum loading over a short period of time. Tables 11a, 11b, and 11c present a ranking of sites based on the particular nutrient. The relative high nutrient concentrations appear to be a function of large watershed size as shown in the three tables. The accompanying chart beside the nutrient loading table presents the relative position of a sample site to the other tributaries. Note the striking difference between the Paria River and all other sites on the tables and charts.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 9. Mean nitrogen and phosphorus concentrations. Total Total Nitrite Total Kjeldahl plus Nitrate Phosphorus Nitrogen mg/L as N mg/L as P Site Name mg/L as N Bright Angel Creek 0.08a 0.12 0.05a Clear Creek 0.27a 0.21a 0.07 a Crystal Creek 0.18 0.43 0.02c Deer Creek 0.11a 0.26 0.03a Diamond Creek 0.24 1.54 0.07b Havasu Creek 0.11a 0.24 0.03b Hermit Creek 0.11a 0.62 0.02c Kanab Creek 0.39 1.20 0.27a Matkatamiba Creek 0.14 0.94 0.03b a Monument Creek 0.11 0.03b 2.83 Nankoweap Creek 0.11d 0.16a 0.05b Paria River 0.88 0.48d 3.45d Royal Arch Creek 0.16 0.93 0.05a Shinumo Creek 0.11 0.05a 0.07b a Spring Canyon Creek 0.15 1.06 0.02 Tapeats Creek 0.10b 0.13 0.05 Three Springs Creek 0.22 0.03b 2.71 Notes: a - one of 4 samples was at the Method Reporting Limit b - two of 4 samples were at the Method Reporting Limit c - three of 4 samples were at the Method Reporting Limit d - one of the four sample analyses was performed past the holding time. Red highlighted values indicate high or exceptionally high measured concentrations compared to other sites Total Kjeldahl Nitrogen Method Reporting Limit was 0.05 mg/L Total Nitrite plus Nitrate Method Reporting Limit was 0.02 mg/L Total Phosphorus Method Reporting Limit was 0.02 mg/L All samples at all sample sites for ammonia nitrogen as N were either at or near the Method Reporting Limit of 0.02 mg/L and therefore are not tabled.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 10. Comparison of mean nutrient concentrations among sample sites. Bright Angel Creek
TKN = 0.08 mg/L Nitrite+Nitrate = 0.12 mg/L Phosphorus = 0.05 mg/L
Clear Creek
TKN = 0.27 mg/L Nitrite+Nitrate = 0.21 mg/L Phosphorus = 0.07 mg/L
Crystal Creek
TKN = 0.18 mg/L Nitrite+Nitrate = 0.43 mg/L Phosphorus = 0.02 mg/L
Deer Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 0.26 mg/L Phosphorus = 0.03 mg/L
Diamond Creek
TKN = 0.24 mg/L Nitrite+Nitrate = 1.54 mg/L Phosphorus = 0.07 mg/L
Havasu Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 0.24 mg/L Phosphorus = 0.03 mg/L
Hermit Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 0.62 mg/L Phosphorus = 0.02 mg/L
Kanab Creek
TKN = 0.39 mg/L Nitrite+Nitrate = 1.20 mg/L Phosphorus = 0.27 mg/L
Matkatamiba Creek
TKN = 0.14 mg/L Nitrite+Nitrate = 0.94mg/L Phosphorus = 0.03 mg/L
Monument Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 2.83 mg/L Phosphorus = 0.03 mg/L
Nankoweap Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 0.16 mg/L Phosphorus = 0.05 mg/L
Paria River
TKN = 0.48 mg/L Nitrite+Nitrate = 0.88 mg/L Phosphorus = 3.45 mg/L
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 10. Continued. Royal Arch Creek
TKN = 0.16 mg/L Nitrite+Nitrate = 0.93 mg/L Phosphorus = 0.05 mg/L
Shinumo Creek
TKN = 0.11 mg/L Nitrite+Nitrate = 0.05 mg/L Phosphorus = 0.07 mg/L
Spring Canyon Creek
TKN = 0.15 mg/L Nitrite+Nitrate = 1.06 mg/L Phosphorus = 0.02 mg/L
Tapeats Creek
TKN = 0.10 mg/L Nitrite+Nitrate = 0.13 mg/L Phosphorus = 0.05 mg/L
Three Springs Creek
TKN = 0.22 mg/L Nitrite+Nitrate = 2.71 mg/L Phosphorus = 0.03 mg/L
Note: 1. Axis scales are proportional to the maximum values and are not consistent among diagrams. 2. "N" represents nitrite plus nitrate.
Nitrite + Nitrate lbs/day n=4 n=3 a 40 21 8 7 13 16 13 13 69 24 99 b 5 3 329 417 2 <1 4 2 14 13 1758 154 9 4 13 9 3 b 136 53 10 5 Total Phosphorus lbs/day n=4 n=3 a 26 7 13 <1 1 <1 2 1 2 2 12 b <1 <1 25 19 <1 <1 <1 <1 2 2 769 37 1 <1 38 5 <1 b 85 17 <1 <1
Table 10. Nutrient loadings on Grand Canyon tributaries.
Site Name Bright Angel Creek Clear Creek Crystal Creek Deer Creek Diamond Creek Havasu Creek Hermit Creek Kanab Creek Matkatamiba Creek Monument Creek Nankoweap Creek Paria River Royal Arch Creek Shinumo Creek Spring Canyon Creek Tapeats Creek Three Springs Creek TKN lbs/day n=4 n=3a 40 11 57 1 8 3 7 4 8 4 45 b 1 1 61 68 <1 <1 <1 <1 6 4 90 96 2 <1 37 15 <1 b 29 187 <1 <1
Note: (a) Loadings calculated with n=3 represent average loadings closer to actual daily values when high flow events are removed. (b) Flood flows absent and the measured flows were consistent for the four sample dates. The MRL, 0.05 mg/L for TKN and 0.02 mg/L for nitrite plus nitrate and phosphorus, was used in the calculations as the concentration value. Red highlighted values indicate the highest estimated loading compared to other sites.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 11a. Typical daily TKN loadings.
Rank 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Sample Site/Watershed Area Paria River, 1410 sq. mi. Kanab Creek, 2311 sq.mi. Havasu Creek, 2966 sq.mi. Tapeats Creek, 84 sq.mi. Shinumo Creek, 86 sq.mi. Bright Angel Creek, 100 sq.mi. Diamond Creek, 275 sq.mi. Deer Creek,17 sq.mi. Nankoweap Creek, 33 sq.mi. Crystal Creek, 44 sq.mi. Clear Creek, 36 sq.mi. Hermit Creek, 12 sq.mi Royal Arch Creek, 15 sq.mi. Spring Canyon Creek, 22 sq.mi. Three Springs Creek, 17 sq.mi. Matkatamiba Creek, 33 sq.mi. Monument Creek, .4 sq.mi. lbs/day 96 68 45 29 15 11 4 4 4 3 1 1 <1 <1 <1 <1 <1
Typical Daily TKN Loadings 100 Po unds per Day 80 60 40 20 0 1 23 4 56 7 8 9 10 11 12 13 14 15 16 17 Ra n k e d Sample Site
Table 11b. Typical daily total nitrite plus nitrate loadings.
Rank 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Sample Site/Watershed Area Kanab Creek, 2311 sq.mi. Paria River, 1410 sq. mi. Havasu Creek, 2966 sq.mi. Tapeats Creek, 84 sq.mi Bright Angel Creek, 100 sq.mi Diamond Creek, 275 sq.mi. Crystal Creek, 44 sq.mi Nankoweap Creek, 33 sq.mi Deer Creek,17 sq.mi Shinumo Creek, 86 sq.mi. Clear Creek, 36 sq.mi Hermit Creek, 12 sq.mi Three Springs Creek, 17 sq.mi Royal Arch Creek, 15 sq.mi Spring Canyon Creek, 22 sq.mi Monument Creek, .4 sq.mi Matkatamiba Creek, 33 sq.mi lbs/day 417 154 99 53 40 24 16 13 13 9 7 5 5 4 3 2 <1
Typical Daily Total Nitrite Plus Nitrate Loadings 500 Po unds per Day 400 300 200 100 0 1 23 4 56 7 8 9 10 11 12 13 14 15 16 17 Ra n k e d Sample Site
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 11c. Typical daily total phosphorus loadings.
Rank 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Sample Site/Watershed Area Paria River, 1410 sq. mi. Kanab Creek, 2311 sq.mi. Tapeats Creek, 84 sq.mi Havasu Creek, 2966 sq.mi. Bright Angel Creek, 100 sq.mi Shinumo Creek, 86 sq.mi. Diamond Creek, 275 sq.mi. Nankoweap Creek, 33 sq.mi Deer Creek,17 sq.mi Clear Creek, 36 sq.mi Crystal Creek, 44 sq.mi Hermit Creek, 12 sq.mi Royal Arch Creek, 15 sq.mi Spring Canyon Creek, 22 sq.mi Matkatamiba Creek, 33 sq.mi Three Springs Creek, 17 sq.mi Monument Creek, .4 sq.mi lbs/day 397 19 17 12 7 5 2 2 1 <1 <1 <1 <1 <1 <1 <1 <1
Typical Daily Total Phosphorus Loadings 500 Po unds per Day 400 300 200 100 0 1 23 4 56 7 8 9 10 11 12 13 14 15 16 17 Ra n k e d Sample Site
Suspended Sediment Concentration (SSC)
Sediments as bed load and suspended particles in the water column play a significant role in the ecology and morphology of stream channels. Sediments may have either a positive or negative influence on the channel. Most undisturbed watersheds have balance between flows and sediment transport. Unregulated streams are dynamic and reshape themselves continually. Portions of the sediment load are deposited in the channel, forming bars and riffles, and on the floodplain. These deposits may be either of short or long duration. Streams carrying high sediment loads may likely have an imbalance in the flow and sediment load. The disparity may be the result of anthropomorphic manipulations of the watershed environment or of natural conditions; e.g., a high gradient, presence of erodible soils, deserts, or lightly vegetated landscapes. When streams have an imbalance between flow and sediment load, sediments fill lakes and reservoirs and are one of the most important environmental problems throughout the world. Sediment is a important water quality problem in Arizona streams (ADEQ, 2004). Besides filling lakes and reservoirs, SSC also has an adverse effect on the biological life of aquatic organisms and it affects the water quality of drinking, recreational and industrial water. SSC can serve as a carrier and storage agent of many kinds of pollutants such as phosphorus, nitrogen, and a variety of agricultural chemicals. Total SSC is composed of two fractions: fine and coarse. Fine Fraction consists of particles less than 62 microns. Paria River is the largest contributor of fine and coarse particles being discharged into the Colorado River (Table 12). The greatest amount of fine particles was 20,000 mg/L in the July 2005 sample and 7,200 mg/L of the coarse fraction in the July 2004 sample. Kanab Creek had one fine fraction sample (July 2004) of 1,400 mg/L, which was the second largest amount of the remaining fifteen sample sites. Coarse fraction samples for all streams
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 except Paria River were below 350 mg/L. Figure 11 illustrates the different amounts of the two fractions carried by each stream as percentage of total SSC. There is a good relationship between the lowest and highest fine fraction SSC concentrations and rim side origin. Six of the south rim side streams had the lowest fine fraction SSC concentrations while seven of the north rim side streams had the highest concentrations. The lowest total SSC concentrations were samples taken near a spring source. The relationship of flow to total SSC is strongest at Paria River, Bright, Clear, Crystal, Deer, Shinumo, and Tapeats Creeks. When concentrations are converted to sample day loadings, Paria River is carrying approximately 1,100 tons a day or 392,000 tons a year total SSC. The majority of the streams sampled, however, carry very little suspended sediment. Table 13 reveals that when flood flows are removed from the loading calculations, all but Paria River, Tapeats Creek, Deer Creek, Nankoweap Creek and Clear Creek carry, on the average, one ton or less total SSC per day.
Table 12. Fine and Coarse Suspended Sediment Fraction concentrations by site. Fine Fraction, mg/L Coarse Fraction, mg/L Site Name
Bright Angel Cr. Clear Creek Crystal Creek Deer Creek Diamond Creek Havasu Creek Hermit Creek Kanab Creek Matkatamiba Creek Monument Creek Nankoweap Creek Paria River (a) Royal Arch Creek Shinumo Creek Spring Canyon Creek Tapeats Creek Three Springs Creek
July '04
Jan. '05
Mar. '05
July '05
July '04
Jan. '05
Mar. '05
July '05
Note: The ND MRL for SSC is 5.0 mg/L. (a) Sample dates were July and November 2004 and January and April 2005. The A&Wc and A&Ww chronic numeric water quality standard for total suspended sediment concentration is 80 mg/L (AAC, 2002). This standard is the geometric mean of the most recent four samples and "applies to a surface water that is at or near base flow and does not apply to a surface water during or soon after a precipitation event." There was one exceedence of this standard during the study period. The geometric mean of the four Paria River samples is 6685 mg/L.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Figure 11. Percentages of Coarse and Fine Fractions of Suspended Sediment at Grand Canyon tributary sites.
Coarse Fraction Suspended Sediment
Fine Fraction Suspended Sediment
Nankoweap Creek.
Kanab Creek
Paria River
Havasu Creek
Crystal Creek
Matkatamiba Creek
Clear Creek
Deer Creek
Monument Creek
Diamond Creek
Tapeats Creek
Bright Angel Creek
Three Springs Creek
Shinumo Creek
Note: Sample sites that did not have both the concentrations of the Fine Fraction and the Coarse Fraction above the MRL of 5.0 mg/L are not represented (Crystal, Hermit, Royal Arch, and Spring Canyon Creeks). The MRL of 5.0 mg/L was used in the calculations at sample sites that had concentrations where at least one of the fractions was above the MRL.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Most sediment is transported during periods of high water flows and high velocities. Many of the sampled streams had at least one high flow event when visited. These high flow events and the associated increase in suspended sediments can provide a useful estimate of watershed conditions. Table 14 presents estimated loadings based on watershed area in tons of suspended sediment per unit mile. Previous data has shown the Paria River contributing significant loads to the Colorado River, but two creeks (Tapeats and Shinumo) having less than 90 square miles of watershed area either exceed or equal the load from the Paria River on a square mile basis. The loads were calculated from a single high flow and likely represent a short duration condition.
Turbidity is a measure of how water scatters light and is a gage of the degree to which the water loses its transparency due to the presence of suspended particulates. The more total suspended solids in the water, the murkier it appears and the greater the turbidity. Turbidity is considered by some investigators to be a good measure of water quality. Four field turbidity measurements at the Paria River and one at Kanab Creek recorded values above 1000 NTU, which is the upper limit of the turbidity meter. Ten sample sites had turbidity measurements between 10 NTU and 1000 NTU (Figure 12). The remaining five sites, not shown, had all four measurements below 10 NTUs. The highest turbidity measurement associated with the highest estimated flow was at Bright Angel Creek (195 cfs), Clear Creek (195 cfs), Shinumo Creek (135 cfs), and Tapeats Creek (720 cfs).
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 13. Daily Suspended Sediment Concentration loadings at sample sites with and without flood flows.
N = 4, All Samples Included N = 3, Flood Flow Samples Removed Mean Mean Mean Mean Fine Coarse Total Mean Fine Coarse Mean Total Fraction, Fraction, SSC, Fraction, Fraction, SSC, tons/day tons/day tons/day tons/day tons/day tons/day
872 70 21 16 8 15 7 2 2 1 0.2 0.01 0.01 0.01 0.003 0.003 0.002 247 95 33 30 15 1 5 0.2 1 1 0.1 0.01 0.01 0.01 0.006 0.003 0.003 1119 165 54 46 23 16 12 2 3 2 0.3 0.02 0.02 0.02 0.009 0.006 0.005 No Flood 93 0.5 0.2 0.5(a) 18 0.05 3 No Flood 1(a) 0.02 0.005 No Flood No Flood 0.004(a) No Flood No Flood No Flood 0.2 0.5 0.2 0.2(a) 1 0.02 0.3 No Flood 0.5(a) 0.02 0.005 No Flood No Flood 0.008(a) No Flood No Flood No Flood 93 1 0.4 0.7 19 0.07 3 No Flood 1.5 0.04 0.01 No Flood No Flood 0.012 No Flood No Flood
Site Name
Paria River Tapeats Creek Shinumo Creek Bright Angel Creek Kanab Creek Clear Creek Havasu Creek Deer Creek Crystal Creek Nankoweap Creek Diamond Creek Royal Arch Creek Matkatamiba Creek Hermit Creek Three Springs Creek Spring Canyon Creek Monument Creek
Note: (a) Site did not have a flood; the low flow was the outlier and omitted from the calculation. Red highlighted values indicate exceptionally high loadings compared to other sites
Table 14. Creeks having the highest suspended sediment loadings per square mile of watershed area.
Site Tapeats Creeka Shinumo Creeka Paria River Clear Creek Bright Angel Creeka Deer Creek Flow, cfs 720 135 50 47 195 23 SSC, tons/day 213 182 2809 49 88 1 Watershed Area, sq. mi. 84 86 1410 36 100 17 SSC, tons/sq. mi. 3 2 2 1 1 0.1
a ? An estimated discharge. Stream at time of sampling was in flood
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ____________________________________________________________________________________________________________
Figure 12. Turbidity as NTU by site and date. Bright Angel Creek Clear Creek Diamond Creek Havasu Creek
Kanab Creek
Matkatamiba Creek
Nankoweap Creek
Shinumo Creek
Tapeats Creek
Three Springs Creek
Note: 1. Turbidity at Kanab Creek on 28 July 2004 exceeded 1000 NTU. 2. Missing data point at Spring Canyon Creek and Three Springs Creek on 31 July 2004. 3. Sites having four turbidity measurements less than 10 NTU are not shown. 4. Paria River having four turbidity measurements above 1000 NTU is not shown.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
The occurrence of pathogenic microorganisms in water supplies can be a threat to human health. Historically, fecal coliform and total coliform were used as indicator organisms for fecal contamination of water, but these groups included bacteria from non-human sources and could give false positives for human contamination. Escherichia coli (E. coli) is found in the gastrointestinal tract and feces of all mammals. The recent development of simple plating tests for the detection of E. coli bacteria has replaced the formerly used coliform tests. To process the sample, the subject water is filtered through a 0.45 micron filter, placed on mTEC media, and incubated at 35 ?C for 24 ?2 hours. Upon completion of the incubation period, the bacteria colonies are immediately counted and reported as the number of colony forming units per 100 milliliters of water (cfu/100 ml). If large or small numbers of colonies are present on the filter, a false representation of E. coli contamination may result. Valid and statistically reliable counts are from an ideal colony count of between 20 and 60 colonies per media plate. Counts from non-ideal conditions, however, are reported with a qualifying notation. Each state develops water quality standards based upon criteria determined under Section 304 (a) of the Clean Water Act of 1972 and its amendments. In Arizona, the acute water-quality standard for a grab sample of E. coli is 235 cfu/100 ml and the chronic standard is 126 cfu/100 ml for the Full Body Contact designated use, which is the most stringent standard of the designated uses for bacteria. The chronic standard is determined from the geometric mean of the last four samples taken at least 24 hours apart. When E. coli counts exceed either standard, there is a statistically greater risk of people experiencing gastrointestinal illnesses.
E. coli colonies were rarely found in the sampled tributaries (Appendix D). Fifty-eight of the 64 samples yielded counts below 50 cfu/100 ml and the median of all samples was 2 cfu/100 ml. These concentrations would be considered at background non-contaminated levels at other streams throughout the state. Media contamination or processing difficulties from four sample sites in July 2004 did not yield E. coli data; the sites were Deer, Kanab, Matkatamiba and Tapeats Creeks. Six of the 64 samples had values of 100 cfu/100 ml or greater (Table 15). Three of those exceeded the acute standard. The geometric mean of four Paria River samples is 411 cfu/100 ml, which also exceeds the chronic water quality standard.
Table 15. Bacteria samples exceeding 100 cfu/100 ml. Sample Site Date cfu/100 ml Qualifier 4 Mar. 2005 103 Bright Angel Creek 1 Aug. 2004 148 Diamond Creek 26 Apr. 2005 250 Paria River Non-ideal count 31 Jan. 2005 317 Paria River Non-ideal count 08 Nov. 2004 200 Paria River Non-ideal count 20 Jul. 2004 1800 Paria River Note: Red highlighted values indicate an exceedence of the acute E. coli water quality standard of 235 cfu/100 ml.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
The relationship between flow, E. coli colony counts, rain on day of sampling and rain within 24-hours previous to sampling were evaluated. With the exception of Bright Angel Creek, there were no discernable effects of these conditions on E. coli populations. Colonies were not observed on the media plate for the January sample which had light rain on sample day, heavy rain the previous day, and moderate flow at day of sampling. It is likely that this sample was taken on the receding hydrograph and the channel had been scoured of some biological life. Flood flows during the May sampling and heavy rain previous to day of sampling appears to have decreased E. coli counts when compared to dates without previous rain and with low flow (Table 16). Table 16. Effects of flow and rain on E. coli colony counts at Bright Angel Creek.
Date 23 July 2004 7 January 2005 4 March 2005 3 May 2005 Rain at time of sampling None Light None None Rain within previous 24-hours to sampling None Heavy None Heavy Flow, cfs 16 35 45 195 J E. coli colony counts/100 ml 22 B ND 103 ND
B ? Non-ideal colony count ND ? No colonies observed on media J ? Estimated flow, stream at flood stage Conclusions
The presence of E. coli in Grand Canyon tributaries was minimal and within normal background non-contaminated levels with the exception of the Bright Angel Creek and Paria River. The Paria consistently had high E. coli counts during the study period and 75% of the grab samples were not in compliance with the acute water quality standard (235 cfu/100 ml). The chronic standard (126 cfu/100 ml), calculated from four samples taken over a nine month period, was exceeded. Caution and the necessary protective gear should be applied when contacting water at any time of the year from the Paria River. Study objectives did not address the issue of human impacts on water quality due to recreation (hiking, camping, canyon boat tours) and habitation of permanent residents within the Canyon. The bacteria data presents limited information on this issue which makes it difficult to make definitive statements regarding human impacts and threats to human health. Generally, however, the low E. coli counts, in compliance with state water quality standards, appear to present a favorable condition for contact with tributary waters. It is recommended that upstream/downstream bacteria samples be taken in those areas where human usage is high to corroborate these findings.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
While the results from water chemistry analysis have discovered a few significant water quality issues, the biological data presents a different view, but with qualifications. ADEQ's bioassessments utilize in-stream macroinvertebrate data to provide an assessment of the condition of aquatic life. These assessments are made by comparison of study site community data (such as species richness) to a statewide composite reference community using an Index of Biological Integrity for cold or warm water streams. Collection and analysis procedures and a description of the Indexes are provided in ADEQ's "Manual of Procedures for the Sampling of Surface Waters" (Lawson, ed., 2006). These Indexes and the statewide reference condition for macroinvertebrates are the basis for the proposed Narrative Biocriteria Standard in the Draft Surface Water Standards (AAC, 2007). Guidelines for analysis of biological data and use of the biocriteria standard are presented in the "Narrative Biocriteria Standard Implementation Procedures for wadeable, perennial streams" (ADEQ, 2006). While this proposed standard has not been adopted as yet, the data are presented here as supplementary information. The narrative biocriterion reads as follows and the associated numeric targets are shown in Table 17.
The Proposed Narrative Biocriterion: "The biological integrity of a wadeable, perennial stream, as determined by the applicable Arizona Index of Biological Integrity (IBI), shall be protected at or above the 25th percentile of reference condition. An IBI score that is at or above the 25th percentile meets the biocriterion. An IBI score that falls below the 10th percentile of reference condition violates the biocriterion. An IBI score that falls between the 10th and 25th percentile of reference score is determined to be inconclusive and a verification sample is required to determine whether there is a violation. If the verification sample IBI score falls below the 25th percentile, the biocriterion is violated." Table 17. Macroinvertebrate Index of Biological Integrity thresholds for wadeable, perennial streams of Arizona. Index of Biological Macroinvertebrate Assessment Integrity Score bioassessment result category Cold water Warm water Greater than the 25th percentile Attaining 52 50 of reference condition Between 10th and 25th Inconclusive 46 ? 51 40 ? 49 percentile of reference Less than the 10th percentile of Impaired 45 39 reference condition
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 This report presents the number and percent of stream sites in each assessment category, and a description of the macroinvertebrate community and habitat conditions occurring during the spring 2005 sample event.
Methods and Study Area
During the spring quarterly sampling event (May 2005), ADEQ collected macroinvertebrate samples from 12 different tributary streams to the Colorado River in the Grand Canyon (Table 18). Macroinvertebrate samples were not collected from two streams where water chemistry was collected in spring 2005. These north rim streams were still in flood stage in May 2005 due to the large amount of winter snow pack and resulting snowmelt, so Bright Angel Creek and Tapeats Creek were unwadeable and therefore biological samples were not collected. Several other streams were still at elevated flow, but wadeable. Macroinvertebrate samples were collected from all of the wadeable Colorado River tributaries, even if at elevated flows, to supplement our biological inventory. Followup samples were collected at low flow during July 2006 on 10 streams. The ten are listed in Table 18; however the data were not available at publication time of this report. These data will be presented in an addendum to this report in 2007. The 2005 macroinvertebrate data are assessed along with an additional 40 historic samples that were collected in July of 1992, 93 and 94 and October of 1997. Samples were collected using Biocriteria Program standard protocols for macroinvertebrate sample collection (Lawson, 2006). Taxonomic identifications (Appendix E) of samples taken in 2005 were conducted by Ecoanalysts Inc, an ADEQ contract laboratory. Analysis of the data was conducted by comparison to the ADEQ cold and warm water Indexes of Biological Integrity which are fully described in the ADEQ Biocriteria Quality Assurance Program Plan (2006). The cold water IBI was applied only to Tapeats Creek, due to the cold water spring fed condition of this stream. The warm water IBI was applied to all other sampled tributaries. The Indexes of Biological Integrity (IBI) were developed for warm water macroinvertebrate communities generally located at elevations <5000 feet above sea level and for cold water communities found at elevations >5000 feet. A statewide network of reference data was used to develop and calibrate the IBIs (Gerritsen and Leppo, 1998; Leppo and Gerritsen, 2000). The IBIs apply to all wadeable, non-effluent dependent, perennial streams located in these regions, with a few exceptions. The cold and warm water indexes consist of several metrics or key attributes of the benthic macroinvertebrate community which best distinguish impairment from the reference condition. The cold water IBI consists of seven metrics selected for their ability to discriminate impairments in cold water streams located at >5000' foot elevation: total taxa richness, Diptera taxa richness, intolerant taxa richness, Hilsenhoff Biotic Index, percent composition by Plecoptera (stoneflies), percent composition by scrapers, and scraper taxa richness. The warm water IBI consists of nine metrics which best discern impairment in warm water streams located at <5000 foot elevation: total taxa richness, Ephemeroptera (mayflies) taxa richness, Trichoptera (caddisflies) taxa richness, Diptera taxa richness, percent composition of Ephemeroptera, percent composition by the dominant taxon, Hilsenhoff Biotic Index score, percent composition by scrapers, and scraper taxa richness. The metrics are calculated from a list of species and their abundances and the total IBI score is an average of the metric scores.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Table 18. ADEQ Macroinvertebrate sample collection history at Colorado River tributary stream sites, 1992-2006. Sampling history Sample Sites Site Code June July July Oct. May July 1992 1993 1994 1997 2005 2006 Bright Angel Creek CGBRA000.44 X X X X Clear Creek CGCLE000.19 X Crystal Creek CMCRY000.05 X X X X X Deer Creek CGDEE000.07 X X X X Diamond Creek CGDIA000.06 X Garden Creek CGGDN000.82 X Havasu Creek CGHAV001.09 X Hermit Creek CGHRM000.08 X X Hermit Creek CGHRM000.27 X Hermit Creek CGHRM001.58 X X X Kanab Creek CGKAN000.26 X X X X Matkatamiba CGMAT000.03 X X Monument Creek CGMON000.19 X X Nankoweap Creek CGNAN000.20 X X X X National Creek CGNAT000.48 X X X X Paria River CGPAR001.62 X Royal Arch Creek CGRYA000.05 X X X X X X Shinumo Creek CGSHN000.11 X Spring Canyon CGSPG000.17 X X X X X Spring Canyon CGSPG000.43 X Tapeats Creek CGTAP000.08 X X X Tapeats Creek CGTAP000.57 X X Three Springs Cyn CGTHS000.04 X X X X
Overall Bioassessment Results
The following results for spring 2005 samples are presented for informational purposes only. The biological samples were "compromised" due to natural flooding conditions. These data cannot be used for 305(b) assessment and 303(d) listing purposes because high floods exclude their use. The terms "attaining, inconclusive, and impaired" are used relative to the Biocriteria assessment categories and do not reflect 305(b)/303(d) assessments. The majority of bioassessment scores for macroinvertebrate samples collected in May 2005 were impaired or inconclusive, when compared to the ADEQ warm water IBI (Table 19). There were 6 samples in the impaired category, 4 inconclusive, and 3 attaining the biocriterion. As a percentage, 46% of the macroinvertebrate samples were in impaired condition. This is a surprisingly high percentage of impaired samples and stream reaches compared to other evaluated streams in the State and considering that there is generally very little human impact in these drainages. This high percentage of 2005 impaired samples is nearly twice the percentage of impaired samples from previous samples collected from 1992-97 (27%) as shown in Figure 13. Throughout all sample events from 1992-2005, there were 24 samples (36%) attaining the - 45 -
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 biocriterion, 19 inconclusive (29%), and 23 impaired (35%). Kanab Creek was the only tributary for which samples attained the biocriterion on all sample events prior to 2005. There were several tributary streams for which all historic samples were impaired: Havasu Creek, Garden Creek, Monument Creek, Nankoweap Creek, Paria River, and Tapeats Creek. Havasu Creek has travertine deposits covering the substrate, a bottom material that is unsuitable for macroinvertebrate colonization. The Paria River has a sand dominated substrate that is unfavorable for insect habitat. Tapeats Creek is a cold water stream, and therefore the macroinvertebrate data has been compared with the cold water IBI; however, more investigation is needed to determine the appropriate reference for this stream.
Table 19. Bioassessment scores for Colorado River tributary streams sampled in May 2005. Stream Warm Aspect Assessment Sampling Sites 2005 Water IBI (North or Category Score South Rim) Clear Creek North 36.0 Impaired Crystal Creek North 34.7 Impaired Diamond Creek above Inconclusive South 48.3 road crossing Diamond Creek below Attaining South 51.4 road crossing Deer Creek North 41.9 Inconclusive Hermit Creek South 51.4 Attaining Kanab Creek North 47.1 Inconclusive Matkatamiba Creek South 38.5 Impaired Monument Creek South 36.3 Impaired Nankoweap Creek North 18.6 Impaired Royal Arch Creek South 42.3 Inconclusive Spring Canyon North 36.5 Impaired Three Springs Canyon South 51.5 Attaining
Figure 13. Comparison of 2005 and historic macroinvertebrate IBI Scores.
Colorado River Tributary streams 1992-1997
Colorado River Tributary streams 2005
Inconclusive 31% Impaired 46%
Inconclusive 29%
Attaining 44%
Impaired 27%
Attaining 23%
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 Analysis of the metric level data reveals more about the status of the macroinvertebrate community in Colorado River tributaries in 2005. Most of the spring 2005 macroinvertebrate metric values did not meet the warm water reference thresholds, as shown in Table 20. The total taxa richness metric value averaged 22 taxa in the 2005 dataset; nearly half the warm water reference threshold value of 37. The number of scraper taxa (algae eaters) and percent composition by scrapers were also notably low at 1.2% for each metric, compared with reference values of 7 and 23.7, respectively (Table 20). The percent composition by mayflies was low compared to the reference threshold, with an average metric value of 44% compared with the reference value of 70%. The percent composition by the single most dominant taxon made up a large percentage of the community abundance, with an average metric value of 59% compared with the threshold value of 19%. The importance of the percent mayflies and percent most dominant taxon metrics relative to the other warm water index metrics is shown in Figure 14. The most dominant organisms were black flies, midges and Baetidae mayflies, all either filter feeders or collector-gatherers. These organisms are the early colonizers which are multivoltine (producing several broods in a single season) and can feed from the organic particles brought by winter runoff. The multivoltine taxa are most resilient, some completing their life cycle in as little as two weeks (Gray, 1981). The dominance of these fast growing organisms, along with the low diversity or taxa richness is indicative of a benthic community in the early successional stage of development. The lack of scrapers is also indicative of early post-flood conditions, where the algal community is not yet well developed. These factors have resulted in low metric values and low IBI scores for the Colorado River tributary streams sampled in May of 2005.
100% 90% 80% 70%
Percent composition
HBI Percent most dominant Percent mayflies Percent scrapers Scraper taxa Diptera rich Mayfly rich Caddis rich Total taxa
60% 50% 40% 30% 20% 10% 0%
Sampling Site
Figure 14. Relative importance of 9 macroinvertebrate metrics in 13 Colorado River tributary sites sampled in May 2005.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 ? May 2005 ____________________________________________________________________________________________________________
Table 20. Warm water macroinvertebrate metric values for Colorado River Tributary streams sampled in May 2005.
Percent Total Caddisfly Mayfly Diptera Scraper Hilsenhoff most Percent Percent Site Aspect taxa taxa taxa taxa taxa Biotic scrapers mayflies dominant richness richness richness richness richness Index taxon 37 9 9 10 7 23.7 70 19.1 4.89 Metric Threshold > CGCLE000.13 CGCRY000.05 CGDEE000.07 CGDIA000.04 CGDIA000.06 CGHRM000.08 CGKAN000.26 CGMAT000.03 CGMON000.19 CGNAN000.20 CGRYA000.05 CGSPG000.17 CGTHS000.04 N N N S S S S S S N S N S 8 9 15 21 20 16 21 12 19 5 18 17 22 0 1 2 3 2 1 4 1 2 0 2 3 5 1 3 3 6 6 5 3 1 2 0 3 2 2 6 4 3 7 7 6 7 4 9 3 6 4 6 0 0 2 0 0 2 2 1 0 0 3 3 2 0 0.0 0.3 0.0 0.0 4.3 3.4 2.3 0.0 0.0 4.0 0.6 0.5 74.4 35.0 83.4 75.7 55.3 70.4 14.6 73.4 8.4 0.0 11.9 3.8 60.1 74.4 50.3 83.0 57.6 49.2 57.7 40.5 73.4 60.5 64.6 50.0 49.6 59.8 4.51 5.31 4.35 5.73 5.90 5.21 5.81 5.12 5.91 5.93 6.02 6.21 4.81 Most dominant taxon Baetis tricaudatus Simulium Baetis tricaudatus Acentrella insignificans Acentrella insignificans Baetis magnus Simulium Baetis magnus Simulium Simulium Chironomidae Chironomidae Fallceon quilleri Functional Feeding Group CollectorGatherer Filterer Collector Collector Collector Filterer Filterer Filterer Collector Collector Collector
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Geographic Analysis of Biological Results
A regression analysis of macroinvertebrate IBI scores with size of the drainage area provided some unexpected results (Figures 15 and 16). We would generally predict an inverse correlation between IBI score and drainage area. However we found that there was a slight positive, but insignificant correlation in both the 2005 (R2=0.15) and 1992-2005 datasets (R2=0.04). The majority of study sites had drainage areas <100mi2, with only Kanab Creek and Havasu Creek having large watershed sizes in the 2300-3000mi2 range. It is difficult to make meaningful inferences when the sample sizes between large and small watersheds are so disproportionate; however, Kanab Creek in 2005 did not have a significantly different warm water IBI score than the smaller Colorado River tributaries. Flood effects may have moderated the watershed effects on the macroinvertebrate community.
Figure 15. Correlation between drainage area and warm water IBI Score, May 2005.
Colorado River Tributaries - 2005
Warm water IBI Score
y = 0.0056x + 39.786 R2 = 0.1451 0 50 0 100 0 15 00 200 0 250 0
Drainage area (mi2)
Figure 16. Correlation between drainage area and warm water IBI score, 1992-1997.
Colorado River Tributaries - 1992-1997
Warmwater IBI score
20.0 y = 0.0024x + 45.47 R2 = 0.0337 10.0 0.00 500.00 1000.00 1500.00 2000.00 2500.00 3000.00
Drainage area, sq. mi.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
North and South Rim Stream Comparisons
There were differences in the composition and species distribution of the macroinvertebrate community (spring 2005) between North and South Rim tributary streams. South Rim stream communities contained nearly twice as many total taxa, mayfly taxa, caddisfly taxa, Diptera taxa, percent scrapers and percent mayflies when compared with North Rim streams. This is likely the result of continued high scouring flows in all the North Rim streams during the May 2005 sample event, from near record snowfall/snowmelt on the North Rim during the previous winter. The overall richness and abundance of macroinvertebrates was greater in South Rim streams because flows were more moderate and the snow pack was significantly less than on the North Rim side. The species distribution was different between North and South Rim stream communities in spring 2005. Baetis tricaudatus was the dominant mayfly at several North Rim streams (Clear, Crystal and Deer Creeks), whereas Baetis magnus was the dominant mayfly in South Rim streams (Hermit, Matkatamiba, Monument, and Royal Arches). Other mayfly taxa were the dominant species in other streams. Baetis notos was the dominant mayfly in Kanab Creek, Acentrella insignificans was dominant in Diamond Creek and Fallceon quilleri was common to Spring Creek and Three Springs Creek. There were no mayflies present in Nankoweap Creek. Stoneflies were only found in two streams in spring 2005; Hesperoperla pacifica in Deer Creek and Capniidae in Kanab Creek, both North Rim streams. The families of caddisflies represented in the 2005 sample included: Hydropsychidae, Hydroptilidae, Philopotamidae, and Rhyacophilidae. The genera Hydropsyche and Ochrotrichia were widely distributed throughout North and South Rim streams. Several caddisfly genera were only found in Spring Creek or Three Springs Creek, such as Chimarra and Rhyacophila. The biomass of macroinvertebrates in North Rim streams was also much less than the South Rim streams. On average the South Rim macroinvertebrate density, from a 3m2 area of stream bottom, was nearly 40% more than in North Rim streams, with the exception of Deer Creek on the North Rim. The macroinvertebrate density in Deer Creek was greater than in any other tributary stream sampled in spring 2005. The constant temperature and flow of this spring-fed stream, which is more insulated from the scouring snowmelt that most other North Rim streams experienced, is likely the reason for higher macroinvertebrate density. Oberlin et al (1999) also found that spring fed tributaries originating within the Grand Canyon had higher macroinvertebrate biomass than tributaries draining large watersheds from outside the Grand Canyon. Spring fed streams maintain a more constant temperature and discharge which is more conducive to algal growth. This growth is of critical importance as a food source and habitat for macroinvertebrates. The streams that originate outside the Grand Canyon and drain large watersheds experience larger and more damaging flow events than the spring fed streams within Grand Canyon. As a result of these high flows, the stream bottom is thoroughly scoured on a seasonal basis. These disturbances reset the benthic community and result in less biomass and diversity of the macroinvertebrate community in the largest tributaries to the Colorado River.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Other Patterns in the Data
Low macroinvertebrate density and diversity are also partly due to physico-chemical factors. Some of the tributary streams with large drainages have water quality characterized by high TDS and CaCO3 with travertine deposits on the stream bottom. These deposits make the stream bottom uninhabitable by bottom dwelling macroinvertebrates and thus limit biological diversity: Havasu Creek and Nankoweap Creek are good examples of this. Other streams with low biomass and diversity are those that are bedrock dominated and have little inhabitable substrate, such as Matkatamiba Creek. Some patterns became evident when examining the data over a period of years. The greatest IBI scores were obtained from samples collected at numerous Grand Canyon tributaries during the fall of 1997. The lowest IBI scores were generally obtained from spring 2005 samples (Appendix F). These findings suggest that the spring index period may not be the ideal sampling period for macroinvertebrates. An alternate sampling period should be considered when re-sampling for macroinvertebrates. The ideal macroinvertebrate sampling period occurs when hydrologic conditions are stable. Therefore, the elevated IBI scores in fall of 1997 suggest that perhaps an October-November fall index period might be the optimum collection period. A comparative analysis was conducted at two sites on Diamond Creek to evaluate the effects of multiple road crossings along the stream near its terminus. CGDIA000.06 was located upstream of the road crossing and CGDIA000.04 downstream. The IBI scores from the two locations were similar and not significantly different, which was unexpected. Typically, poor habitat and muted biological diversity is found below dirt road crossings.
Habitat Results
Extensive physical habitat data was collected at each of the Colorado River tributary monitoring sites at the time of macroinvertebrate sample collection during Spring 2005. These data included percent filamentous algae cover, macrophyte cover, percent fines (<2mm) in the substrate, embeddedness in riffles, percent canopy density of riparian vegetation over the streambed, riparian vegetation identification, and Proper Functioning Condition category of the riparian area (Appendix G). The percent algae cover was generally low among most sites (<1%), with the exception of Spring Canyon Creek where algae cover was >75%. The percent macrophyte cover was also negligible at all sites. The density of macroinvertebrates in Spring Canyon Creek corresponded with the increased algae cover. Primary production is generally greatest in tributaries originating within the Grand Canyon and the periphyton is the most important food source for macroinvertebrates (Oberlin, 1999). The large percent cover of periphyton in Spring Canyon suggests that it was not severely affected by winter flooding due to its small watershed size (22 mi2) and perhaps the mean elevation of its drainage area. Substrate conditions were generally good, with a mixture of particle sizes and low embeddedness. Percent fines (<2mm) ranged from 0-16% with a mean of 5.2% and embeddedness ranged from 0-28% with a mean of 20%. These conditions are ideal for macroinvertebrate habitat. Percent fines in this range will meet the proposed ADEQ Surface Water bottom deposits standard of 50%. The overall stream channel habitat was dominated by riffle habitat (94%), with very little pool habitat (2.6%), due to the steep gradient of these canyon - 51 -
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005 channels as they approach the Colorado River. The steep channel gradient and dominant erosional habitat (riffles) of the Colorado River tributaries are key determinants of the hydrology, stream ecology and condition of the benthic community. Riparian vegetation was minimal in the Colorado River tributary channels during spring 2005, having been recently scoured by the high flows from winter snowmelt. Riparian tree cover on the channel floodplains was generally <20% except for Royal Arch Creek (25%) and Spring Canyon Creek (40%). The dominant riparian community type was cottonwood-willow. A riparian corridor assessment was conducted using the Bureau of Land Management's "Proper Functioning Condition" method. Conditions ranged from "proper functioning" for a Grand Canyon stream (n=4) to "non-functional" (n=2), with several streams classified as "functional atrisk". These riparian assessments are not reliable indicators of normal conditions in Grand Canyon tributary streams, because of the recent scouring winter floods and because these disturbance-prone channels may not meet expectations of other warm-water healthy riparian communities.
A definitive statement on the attainment of the biocriterion cannot be made at this time due to high flow conditions during sampling, the possibility of a more appropriate index period for the Grand Canyon ecosystem, and the need to develop a region-specific reference community for Colorado River tributary streams. The macroinvertebrate samples collected during May 2005 were affected by continued snowmelt, high flows and the associated scouring of the stream bottom substrate. The majority of these samples appeared "impaired" when compared with the warm and cold water macroinvertebrate community IBIs; however, the flood and post-flood condition of the investigated streams disallows that data from 305(b) and 303(d) assessments. The flows were exceptionally high in May 2005 due to record snow pack on the North Rim. It is common for Colorado River tributaries to be at flood stage into the month of June, which makes sampling during the ADEQ IBI spring index period problematic. Further research is required to determine whether a fall index period is a more stable hydrologic period, and thus a more appropriate time for macroinvertebrate sampling on Grand Canyon tributary streams. Substrate and channel characteristics limit development of the macroinvertebrate community. When compared to the state biocriterion, 46% of the macroinvertebrate samples were in "impaired" status. This is a high percentage of "impaired" samples for streams which mostly have pristine watersheds, with varying amounts of recreation. Some of the streams have limited habitable substrate, being dominated by either travertine deposits or bedrock. The absence of favorable habitat decreased macroinvertebrate community diversity and biomass. Additionally, the steep channel gradient and dominant erosional habitat of the Colorado River tributaries are key determinants for the hydrology, stream ecology and the condition of the benthic community. These tributary streams are disturbance prone and thus only the moderate to highly tolerant and resilient macroinvertebrate species are present. The most tolerant and ubiquitous taxa were found among all the Colorado River tributaries in 2005 (e.g. black flies, midges and Baetid mayflies), but there were more taxa and biomass present in South Rim streams than North Rim streams, which were still receiving high flow events at time of sampling. - 52 -
A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Despite the high flows and low IBI scores present in the spring 2005 samples, there was a high percentage (27%) of "impaired" IBI scores in the historic dataset as well. While there are factors that can be linked to this impairment (i.e. low percent algae and vegetation cover, and low PFC scores), there are few likely human sources of stress on most of the channels. However, the relationship between biological impairment and recreational use of these streams requires further investigation. The stress on these streams appears to be natural and related to the steep channel gradients and a unique hydrology characteristic of Colorado River tributaries. The biological communities of these disturbance prone tributary streams may not achieve the typical macroinvertebrate community structure and function of other warm water streams across the state; therefore, the warm water IBI scoring criteria may not be applicable. Further research is required to either modify the warm water IBI scoring criteria to meet best attainable conditions in these tributary streams or develop a discrete IBI for the unique streams of this region.
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
AAC, 2002. Arizona Administrative Code, Title 18, Chapter 11, Article 1, Section 112 Water Quality Standards for Surface Waters,. Office of the Secretary of State, Phoenix, AZ. AAC, 2007. DRAFT - Arizona Administrative Code, Title 18, chapter 11, Article 1 Water Quality Standards for Surface Waters, Biological Criteria and Implementation Procedures, R18-11-108.01. Arizona Revised Statutes (A.R.S.) ?49-225. Water Quality Monitoring Arizona Department of Environmental Quality (ADEQ), 2004. The Status of Water Quality in Arizona ? 2004, Arizona's Integrated 305(b) Assessment and 303(d) Listing Report, Reissued July 2005 to include EPA revisions. Environmental Quality Report #EQR0501. Arizona Department of Environmental Quality. Phoenix, AZ. Arizona Department of Environmental Quality (ADEQ), 2006. Biocriteria Program Quality Assurance Program Plan, Rev. E. Technical Bulletin #TB06-01. Arizona Department of Environmental Quality. Phoenix, AZ. Arizona Department of Environmental Quality (ADEQ). DRAFT 2006 Status of Ambient Surface Water Quality in Arizona ? Arizona's Integrated 305(b) Assessment and 303(d) Listing Report. Phoenix, AZ. Clean Water Act, 1972. Federal Water Pollution Control Act (33 U.S.C. 1251 - 1376; Chapter 758; P.L. 845, June 30, 1948; 62 Stat. 1155). Gerritsen, J. and E.W. Leppo, 1998. Development and testing of a biological index for warmwater streams of Arizona. Tetra Tech, Inc. Owings Mills, MD. Gray, L.J. 1981. Species composition and life histories of aquatic insects in a lowland Sonoran desert stream. The American Midland Naturalist 106(2):229-242. Hem, J.D., 1989, Study and interpretation of the chemical characteristics of natural water: USGS Water-Supply Paper 2254. Lawson, L.L. (ed.), 2006. A Manual of Procedures for the Sampling of Surface Waters. TB 06-0. Arizona Department of Environmental Quality, Phoenix, AZ. Leppo, E.W. and J. Gerritsen, 2000. Development and testing of a biological index for coldwater streams of Arizona. Tetra Tech, Inc. Owings Mills, MD. Oberlin, G.E., J.P. Shannon, and D.W. Blinn. 1999. Watershed influence on the macroinvertebrate fauna of ten major tributaries of the Colorado River through Grand Canyon, Arizona. The Southwestern Naturalist 44(1):17-30. United States Environmental Agency (USEPA), 1998. Integrated Risk Information System, Online Risk Summary for Inorganic Arsenic (4/10/1998).
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A Water Quality Investigation of Seventeen Grand Canyon Tributaries: July 2004 - May 2005
Site Codes and Sample Site Locations
ADEQ Site Code CGBRA000.44 CGBRA001.36 CGCLE000.19 CGCRY000.05 CGDEE000.07 CGDIA000.06 CGHAV000.36 CGHRM000.08 CGKAN000.26 CGMAT000.03 CGMON000.19 CGNAN000.20 CGPAR001.62 CGRYA000.05 CGSHI000.05 CGSPG000.17 CGTAP000.08 CGTHS000.04 Sample Site and Location Bright Angel Creek - Below Phantom Ranch Bright Angel Creek - Above Phantom Ranch Clear Creek - Above Colorado River Crystal Creek - Above Colorado River Deer Creek - Above Colorado River Diamond Creek - Above Mo
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