FECAL COLIFORM BACTERIA SUMMARY SHEET

Transcription

1 FECAL COLIFORM BACTERIA SUMMARY SHEET WATERBODY: Greybull River (Tributary to Big Horn River) (WYBH ) REACH DESCRIPTION: Confluence wi e Big Horn River upstream to Meeteetse, Wyoming. BACKGROUND: The Greybull River was sampled by WDEQ/WQD in 2000 as part of e department s efforts to partition fecal coliform bacteria sources on e reach of e Big Horn River at was listed as not supporting Recreation designated use because of bacteria levels. The 2000 sampling results on e Greybull River were summarized in e Big Horn River and Tributaries report, and are presented again in e Data Results portion of is report. The United States Geological Survey (U.S.G.S.) operates e Greybull River at Meeteetse gaging station (Station No ). Fecal coliform bacteria data are collected quarterly at is site. A summary of e U.S.G.S. data from 1995 rough 2000 are provided in Table 1. Table 1. Fecal Coliform Bacteria Data, Greybull River at Meeteetse Station. Nov rough July, Date Fecal Coliform Bact. (cfu / 100 ml.) Date Fecal Coliform Bact. (cfu / 100 ml.) 11/01/95 5* 06/24/ /28/96 6* 09/03/ /28/ /28/98 16* 09/10/96 13* 02/26/99 10* 10/30/ /25/ /25/ /18/99 21* 06/26/ /27/99 14* 08/21/97 74* 01/26/ /03/97 2* 06/07/ /25/ /19/00 58 * Colony count outside optimum count range. The Greybull River at Meeteetse data indicate fecal coliform bacteria counts greater an 200 cfu/100 ml. have occurred only in e mons of May and June. Counts oer an in ose

2 Page 2 mons are generally very low. These data suggest at any 30-day geometric mean, and/or 24-hour geometric mean sampling at e Meeteetse location should be conducted during e period of May 15 rough June 30. In addition, a paogen indicator synoptic study conducted by e U.S.G.S. in 2000 included four stations on e Greybull River. Provisional fecal coliform bacteria and e.coli counts on e Greybull River are given in Table 2. The date of e U.S.G.S. sampling was July 19, Table 2. U.S.G.S. Paogen Synoptic Study Data (Provisional). Greybull River, July 19, Location Fecal Coliform Bacteria e. coli Greybull River at Meeteetse, WY Greybull River Near Park Co. Line * Greybull River Near Burlington, WY * Greybull River at Greybull, WY 2,200* 1,600* * Colony counts outside of optimum plate count range. The provisional data obtained in is study indicate a definite increase in bacteria from e town of Meeteetse to e confluence of e Greybull River wi e Big Horn River at e town of Greybull. The largest increase in colony density occurred between e towns of Burlington and Greybull. The WDEQ/WQD sampled e Greybull River in 2001 in an effort to better partition out bacteria loading in e river. WDEQ STATION DESCRIPTIONS: Greybull River at Greybull. This station is located at e Highway crossing of e Greybull River at Greybull, Wyoming. This station is approximately ½ - mile upstream of e confluence of e Greybull River wi e Big Horn River. Greybull River near Otto. This station is located at e County Road 16 crossing of e Greybull River, approximately 1.5 miles sou of e town of Otto, Wyoming. Greybull River at Meeteetse. This station is located immediately upstream of e Highway 120 crossing of e Greybull River in e town of Meeteetse, Wyoming. DATA RESULTS:

3 Page 3 Year Greybull River at Greybull Station fecal coliform bacteria and water quality data results for e year 2000 sampling are shown in Table 3. The 5-sample, 30-day geometric mean (natural log) for e Greybull River at Greybull greatly exceeded e WDEQ/WQD fecal coliform bacteria water quality standard of 200 colonies per 100 ml. In addition, four of e five samples (80%) exceeded 400 colonies per 100 ml. The 2000 data indicate at e designated use of Recreation is not fully supported. The reach not being supported is e Greybull River from its confluence wi e Big Horn River, upstream an undetermined distance. The two observations where fecal coliform bacteria levels exceeded 1,000 cfu/ 100 ml. bo occurred wi high turbidity values (> 1,000 NTU), suggesting a possible link between bacteria and runoff or overland flow contributions to e river. Table 3. Year 2000 Fecal Coliform and Water Quality Data, Greybull River at Greybull. Greybull Greybull 13:35 09:44 11:30 11:32 11:35 Geometri c Mean 610 * ,300 * 1,365 * 990 * 1,394 ph (std. units) NA Cond. (us/cm) ,016 1,024 1,111 NA Temp. ( C) NA Turbidity (NTU) > 1,000 > 1, NA * Colony count outside optimum count range of colonies per plate. Mid-day water temperatures on e Greybull River at Greybull also exceeded e WDEQ/WQD cold water game fish standard of 20 C on bo July 6 and 7, Year Fecal coliform bacteria sampling was conducted on e Greybull River to help partition out potential areas of loading in e watershed. A summary of e bacteria and water quality monitoring is given in Table 4. The ree sample periods (May, June, and July) in 2001 represent ree different runoff event periods. The May 22 and 23, 2001 samples reflect an early summer, dry-conditions period. The Greybull, Wyoming NOAA weaer station reported one occurrence of measurable precipitation (0.01 inches on May 20, 2001) in e two week period before e May 22, 2001 sampling. The June 14, 2001 samples were collected during a significant rain and snow precipitation event wi significant surface runoff. The Greybull weaer station reported 0.12 inches on June 12, 0.48 inches on June 13, and 0.07 inches of precipitation on June 14.

4 Page 4 The July 10, 2001 samples reflect a mid-summer, dry conditions period. The Greybull weaer station reported two measurable precipitation events between June 28 and July 10, ose being 0.01 inches of precipitation on bo July 9 and July 10. Flows at e time of e July 10 sampling were extremely low due to irrigation widraw. The samplers estimated flows on e Greybull River near Otto to be 1 cubic foot per second. Table 4. Year 2001 Fecal Coliform and Water Quality Data. Greybull Rivers Stations. Greybull River At Greybull 05/22/01 06/14/01 07/10/01 Time (24 hr.) 09:28 08:27 13:25 Fecal Coliform Bact. 860 * 2,600 (rep. 1) 3,500 (rep. 2) 540 ph (std. units) Cond. (us/cm) Dissolved Oxygen (mg/l) Temp. ( C) Turbidity (NTU) 36.2 > 1, Greybull River Near Otto 06/14/01 07/10/01 07/10/01 Time (24 hr.) 09:07 08:25 13:00 5,600 * Not Collected 220 ph (std. units) Cond. (us/cm) 549 1,599 1,585 Dissolved Oxygen (mg/l) Temp. ( C) (rep.1) 30.3 (rep.2) Turbidity (NTU) > 1,000 Not Collected Table 4 cont. on Page 5 * Colony counts outside optimum count range of colonies per plate.

5 Page 5 Table 4. Year 2001 Fecal Coliform and Water Quality Data. Greybull Rivers Stations (cont.). Greybull River at Meeteetse 05/23/01 Time (24 hr.) 10:00 < 10* ph (std. units) 8.51 Cond. (us/cm) 310 Dissolved Oxygen (mg/l) Temp. ( C) 10.6 Turbidity (NTU 5.33 Burlington WWTF 05/22/01 Time (24 hr.) 10:48 <3* ph (std. units) 7.65 Temp. ( C) 14.0 T. Residual Chlorine (mg/l) 0.2 Meeteetse WWTF 05/23/01 Not Discharging * Colony count outside optimum count range of colonies per plate. Fecal coliform bacteria counts are quite high for e five Greybull River at Greybull and Greybull River at Otto samples. Four of ese 5 counts exceeded 400 cfu / 100 ml. The highest Greybull and Otto counts occurred during e June runoff conditions. The lowest Greybull and Otto counts occurred during e mid-summer dry-condition period, possibly a factor of minimal surface runoff and increased solar radiation on e low-flow conditions. May 2001 counts on e Greybull River at Meeteetse and of e town of Burlington wastewater treatment facilities effluent were bo low. The Meeteetse wastewater treatment facility was not discharging on May 23, 2001 at 10:30. As suggested by e U.S.G.S. synoptic study, fecal coliform bacteria counts increased dramatically between e towns of Meeteetse and Greybull during e WDEQ/WQD May 22, 2001 sampling.

6 Page 6 Water temperatures observed during e July 10, 2001 sample event were quite high. The instantaneous, midday temperatures at e Greybull River at Greybull and near Otto sites were 27 and 30.6 C, respectively. Water temperature at e Greybull River near Otto site exhibited a temperature change of 10.3 C between e morning (20.3 C at 08:25) and afternoon (30.6 C at 13:00) readings. QUALITY ASSURANCE / QUALITY CONTROL: All data runs contained blanks. None of e blank plates exhibited any colony forming units. All fecal coliform bacteria samples had at least 3 aliquots run. Several sets of data had plate counts outside e optimal count range of colonies per plate. These data are identified. One fecal coliform bacteria sample (Greybull River at Greybull, June 14) was a duplicate. The duplicate counts of 2,600 and 3,500 have a relative percent difference (natural log values) of 3.8%. One temperature reading was duplicated (Greybull River near Otto, July 10). The duplicate readings of 30.6 and 30.3 have a relative percent difference of 1%. All data collected went rough a quality control check and were validated. Conducted By: Jack Smi, Monitoring Supervisor Date: August 28, 2001 F:\USERS\JSMITH\JACK\REPORTS\Greybull.fec.wpd