2006 WATER MONITORING REPORT

Transcription

1 26 WATER MONITORING REPORT May 27 Prepared for: South Washington Watershed District Prepared by:

2

3 Memorandum To: Matt Moore South Washington Watershed District Administrator From: Wendy Griffin, Travis Thiel, Tim Sundby, Erik Anderson, and Jessica Arendt--Washington Conservation District Date: May 2, 27 Re: SWWD 26 Monitoring: MS1, MS2, Powers, 1 th Street, St. Paul Park, Newport, Fox Run, Tamarack Road, Bailey Lift Station, 8 th Street, 9 th Street, North Ravine of East Inlet of Cottage Grove Ravine Park (North Ravine), East Ravine of East Inlet of Cottage Grove Ravine Park (East Ravine), Armstrong Lake, Powers Lake, Cottage Grove Ravine Park Lake, Lake Gages, & Observation Wells At the request of the South Washington Watershed District (SWWD), the Washington Conservation District (WCD) conducted stream monitoring at four existing stream monitoring stations and two new stream monitoring stations (MS1, MS2, Powers, 1 th Street, Newport, and St. Paul Park), monitored six stormwater sites (North Ravine, East Ravine, Fox Run, Tamarack Road, 8 th Street, and 9 th Street), monitored water quality and level on Armstrong Lake, Cottage Grove Regional Park Lake, and Powers Lake, monitored level and precipitation on Bailey Lake (at the Lift Station), installed and read nine lake staff gages, and monitored seven groundwater observation wells. The locations of the monitoring sites can be found in Figure 1. The following report summarizes our methods and results for monitoring conducted from January 1 - December 31, 26. This report and the accompanying data will also be provided in an electronic format. Stream Sample Sites: MS1, MS2, Powers, 1 th Street, Newport, & St. Paul Park Continuous stage, velocity, and discharge measurements were taken every 15 minutes at Newport from May 15- October 26, 26, at 1 th Street from April 6-October 31, 26, at Powers from April 13-October 25, 26, at MS1 from April 1-October 26, 26 and at MS2 from April 5-October 25, 26. Discharge measurements were taken every 5 minutes at St. Paul Park from May 15-October 26, 26. Precipitation data was also continuously collected at 1 th Street, Powers, MS2, and MS1 during the same time period for 26. Staff gages were installed and read at 1 th Street, Powers, MS1, and MS2. Field stage measurements were taken in the outflow culverts. Temperature, dissolved oxygen, and transparency tube measurements were also taken. Flow weighted storm event samples, storm event grab samples, snowmelt grab samples, baseflow composite samples, and baseflow grab samples were collected at all stream sites. In addition to these samples, E. coli bacteria grab samples were also taken or were attempted at all six sites. The samples were analyzed at the Metropolitan Council Environmental Services Lab. Values with corresponding greater than/less than symbols presented in data by the Metropolitan Council Environmental Services Lab were divided by two when calculating averages and median values. Stage to discharge relationships were developed at all stream sites, if possible. When the area-velocity probe was covered with debris or erroneous velocity readings were given, stage to discharge relationships had to be used. When data gaps were present, stage/velocity relationships based upon individual site data to interpolate missing data. MS1 and MS2 had backup level logger stage recorders that allowed for data collection during periods when the primary equipment was not recording. 3

4 Stream Continuous Stage Sites: 8 th Street, 9 th Street, North Inlet of East Inlet to Cottage Grove Ravine Park Lake (North Ravine), East Inlet of East Inlet to Cottage Grove Ravine Park Lake (East Ravine), & Bailey Lift Station Continuous stage measurements were taken every 15 minutes at 8 th Street from March 29-October 24, 26, at 9 th Street from April 4-October 24, 26, at North Ravine from March 3-October 24, 26, at East Ravine from March 3-October 24, 26. East Ravine only had one event that was measured that was above zero, thus recorded data was not included in this report. Continuous stage and precipitation measurements were taken every hour at Bailey Lift Station from April 5-October 25, 26. Staff gages were installed and read at 8 th Street, 9 th Street, North Ravine, East Ravine and Bailey Lift Station. Offsets between level logger and staff gage allowed for a continuous stage to be measured. Stage to discharge relationships were developed at the 8 th Street and 9 th Street Sites. Stream Flow and Continuous Stage Sites: Fox Run and Tamarack Road. Continuous stage, velocity, and discharge measurements were taken every 15 minutes at Fox Run from March 3-October 24, 26 and at Tamarack Road from March 29-October 25, 26. Lake Sites: Armstrong Lake, Powers Lake, and Cottage Grove Ravine Park Lake Included in the 26 work plan for SWWD were monitoring of three lakes. Armstrong and Cottage Grove Ravine Park Lake were monitored monthly from April to October. Powers Lake was monitored biweekly from April to October. All lakes were monitored by collecting Secchi transparencies, temperature, and dissolved oxygen profiles. Secchi transparencies are used for general comparisons of water quality across the watershed and for monitoring general water quality trends in a given lake from year to year. Temperature and dissolved oxygen profiles provide information on the in-lake dynamics and how each lake may be functioning each year. All three lakes had surface composite water quality samples taken for analysis of total phosphorus, total Kjeldahl nitrogen, chlorophyll-a concentrations, and total chloride ions. 4

5 Figure 1. SWWD Water Monitoring Locations 5

6 6

7 Sample Sites: MS1, MS2, Powers, 1 th, Newport, and St. Paul Park MS1 (I94) The hydrograph for the MS1 site shows flows from April 1 October 26, 26 (Figure 2). Precipitation was logged from March 3-October 26, 26 (Figure 2). Total discharge during this period was 7,615,256 cf or 175 acre-ft. The peak discharge of 6 cfs was on June 6, 26 from a storm precipitation of 1.55 inches. The highest storm precipitation of 26 occurred during the August 1 st to 2 nd storm, with a total of 2.78 inches. MS1 26 Flow and Daily Rainfall 6 Flow Rate Rainfall cfs in Apr 26 May Jun Jul Aug Sep Oct 3/29/26 4:: PM - 1/27/26 4:: AM. Figure 2. MS1 26 Continuous Flow and Daily Rainfall 7

8 Table 1. MS1 Stream Loading Table Sample Collection Time Loading Interval Sample Type Storm # Start End TSS Interval Interval Interval TP Start End Volume (cf) TSS (lb) TP (lb) Base /1/26 : 3/2/26 : 1,684, Snowmelt Grab 3/22/6 14:15 3/22/6 14: /2/26 : 3/24/26 : 691, Base /24/26 : 3/28/26 : 172, Snowmelt Grab 3/31/6 14:46 3/31/6 14: /28/26 : 4/2/26 : 1,296, 1, Base /2/26 : 4/1/26 12: 55, Snowmelt Grab 4/1/6 12:3 4/1/6 12: /1/26 12: 4/11/26 2: 93,818 1, Base /11/26 2: 4/2/26 13: 469, Storm /2/26 13: 4/21/26 5: 49, Base /21/26 5: 4/28/26 13: 81, Storm /28/26 13: 5/2/26 11: 558,43 7, Base /2/26 11: 5/8/26 16: 6, Storm /8/26 16: 5/8/26 18: 9, Base /8/26 18: 5/8/26 22: 14, Storm /8/26 22: 5/9/26 4: 17,182 2, Base /9/26 4: 5/12/26 5: 273, Storm /12/26 5: 5/12/26 23: 89,877 1, Base /12/26 23: 5/13/26 16: 55, Storm /13/26 16: 5/13/26 22: 43, Base /13/26 22: 5/15/26 14: 11, Storm /15/26 14: 5/15/26 2: 13, Base Grab 5/16/6 8:3 5/16/6 8: /15/26 2: 5/16/26 16: 36, Storm /16/26 16: 5/16/26 23: 26, Base /16/26 23: 5/25/26 21: 283, Storm /25/26 21: 5/26/26 1: 6, Base /26/26 1: 5/29/26 16: 48, Storm /29/26 16: 5/3/26 6: 23, Base Composite 5/3/6 1:52 6/1/6 2: /3/26 6: 6/5/26 19: 53, Storm /5/26 19: 6/5/26 21: 11, Base /5/26 21: 6/5/26 23: 5, Storm Composite 12 6/5/6 23:22 6/6/6 6: /5/26 23: 6/6/26 2: 236,754 6, Base /6/26 2: 6/16/26 21: 336, Storm /16/26 21: 6/17/26 5: 33, Base /17/26 5: 6/17/26 18: 11, Storm /17/26 18: 6/17/26 2: 2, Base /17/26 2: 6/24/26 15: 17, Storm /24/26 15: 6/25/26 13: 35, Base /25/26 13: 6/26/26 17: 1, Storm /26/26 17: 6/27/26 1: 4, Base /27/26 1: 7/13/26 22: 29, Storm /13/26 22: 7/14/26 7: 6, Base Composite 7/14/6 8:41 7/14/6 19: /14/26 7: 7/16/26 8: 5, Storm Composite 18 7/16/6 8:29 7/16/6 13: /16/26 8: 7/16/26 15: 11, Base /16/26 15: 7/19/26 1: 5, Storm Composite 19 7/19/6 1:36 7/19/6 12: /19/26 1: 7/19/26 19: 32, Base /19/26 19: 7/24/26 18: 18,7 9.1 Storm Composite 2 7/24/6 18:14 7/24/6 19: /24/26 18: 7/24/26 23: 37, Base /24/26 23: 8/1/26 3: 42, Storm Composite 21 8/1/6 12:34 8/2/6 8: /1/26 3: 8/2/26 21: 775,753 15, Base /2/26 21: 8/6/26 2: 268, Storm /6/26 2: 8/6/26 6: 18, Base /6/26 6: 8/23/26 4: 229, Storm Composite 23 8/23/6 4:36 8/23/6 8: /23/26 4: 8/23/26 12: 65, Base /23/26 12: 8/24/26 15: 13, Storm Composite 24 8/24/6 15:22 8/24/6 17: /24/26 15: 8/24/26 18: 86,316 1, Storm Composite 25 8/24/6 17:34 8/24/6 22: /24/26 18: 8/25/26 8: 469,375 13, Base /25/26 8: 9/3/26 15: 538, Storm Composite 26 9/3/6 15:52 9/3/6 22: /3/26 15: 9/4/26 7: 21,489 1, Base /4/26 7: 9/1/26 17: 221, Storm /1/26 17: 9/1/26 23: 13, Base Grab 9/13/6 9:45 9/13/6 9: /1/26 23: 9/21/26 14: 11, Storm /21/26 14: 9/23/26 15: 117,648 1, Storm /23/26 15: 9/24/26 6: 56, Base /24/26 6: 1/11/26 5: 214, Storm /11/26 5: 1/11/26 17: 12, Base /11/26 17: 1/16/26 5: 22, Storm /16/26 5: 1/16/26 21: 2, Base /16/26 21: 1/26/26 13: 11, Base /26/26 13: 1/1/27 : 5, Storm Average Base Average 8.79 Snowmelt Average All Average Total 12,2,274 62, SWWD Major Subwatershed Total Acres 1,482 Total TP/TSS(lb/ac/yr) Total TP/TSS (kg/ha/yr) *Italics indicate estimated concentrations based on average base and storm flow concentrations 8

9 Grab and flow weighted composite samples were taken at the MS1 site to determine water quality. Samples were taken during snowmelt and storm runoff, as well as during base flow conditions. The total suspended solids (TSS), total Kjeldahl nitrogen (TKN), total phosphorus (TP), total dissolved phosphorus (TDP), volatile suspended solids (VSS), chemical oxygen demand (COD), and E. Coliform concentrations from all collected samples are listed in Table 2. The highest TSS concentrations were collected in a storm composite on June 6, 26. The highest TP concentration was collected in a storm composite on August 1, 26. The highest TKN concentration was collected in a storm composite on August 1, 26. Metals and other Nitrogen species chemical results are listed in Table 3. Table 2. MS1 26 Sample Chemistry Results Sample Type Start Date End Date TSS VSS TKN TP E. Coliform (#/1 ml) COD TDP Snowmelt Grab 3/22/6 14:15 3/22/6 14:15 8 ~ Snowmelt Grab 3/31/6 14:46 3/31/6 14:46 15 ~ ~.18 Storm Grab 4/1/6 12:3 4/1/6 12:3 296 ~ Base Grab 5/16/6 8:3 5/16/6 8:3 ~1 ~1.58 ~ <.1 Base Composite 5/3/6 1:52 6/1/6 2:26 4 ~ ~.2 Storm Composite 6/5/6 23:22 6/6/6 6: E. Coli Grab 6/14/6 1:4 6/14/6 1:4 186 Base Composite 7/14/6 8:41 7/14/6 19:51 18 ~ ~.49 Storm Composite 7/16/6 8:29 7/16/6 13:23 34 ~ Storm Composite 7/19/6 1:36 7/19/6 12:12 38 ~ ~.14 Storm Composite 7/24/6 18:14 7/24/6 19: ~.31 E. Coli Grab 7/25/6 9:1 7/25/6 9:1 816 Storm Composite 8/1/6 12:34 8/2/6 8:1 324 ~ E. Coli Grab 8/1/6 1:15 8/1/6 1: Storm Composite 8/23/6 4:36 8/23/6 8: Storm Composite 8/23/6 4:36 8/25/6 2:46 2 ~ Storm Composite 8/24/6 15:22 8/24/6 22: ~ Storm Composite 9/3/6 15:52 9/3/6 22: E. Coli Grab 9/6/6 9:3 9/6/6 9:3 488 Base Grab 9/13/6 9:45 9/13/6 9:45 9 ~ E. Coli Grab 1/1/6 8:2 1/1/6 8:2 51 Average

10 Table 3. MS1 26 Sample Metals and Nitrogen Species Chemical Results Sample Type Start Date End Date Copper Nickel Lead Zinc Cadmium Chromium Chloride Nitrite N Nitrate N Nitrogen Snowmelt Grab 3/22/6 14:15 3/22/6 14: < Snowmelt Grab 3/31/6 14:46 3/31/6 14: < <.3.18 ~.4 Storm Grab 4/1/6 12:3 4/1/6 12: < <.3.13 ~.5 Base Grab 5/16/6 8:3 5/16/6 8: < <.3.6 <.2 Base Composite 5/3/6 1:52 6/1/6 2: Storm Composite 6/5/6 23:22 6/6/6 6: ~.5 E. Coli Grab 6/14/6 1:4 6/14/6 1:4 Base Composite 7/14/6 8:41 7/14/6 19: < <.2 Storm Composite 7/16/6 8:29 7/16/6 13: Storm Composite 7/19/6 1:36 7/19/6 12: <.3.92 ~.2 Storm Composite 7/24/6 18:14 7/24/6 19: <.3.79 <.2 E. Coli Grab 7/25/6 9:1 7/25/6 9:1 Storm Composite 8/1/6 12:34 8/2/6 8: < E. Coli Grab 8/1/6 1:15 8/1/6 1:15 Storm Composite 8/23/6 4:36 8/23/6 8: < Storm Composite 8/23/6 4:36 8/25/6 2: < Storm Composite 8/24/6 15:22 8/24/6 22: < Storm Composite 9/3/6 15:52 9/3/6 22: < ~.4 E. Coli Grab 9/6/6 9:3 9/6/6 9:3 Base Grab 9/13/6 9:45 9/13/6 9: < < <.2 E. Coli Grab 1/1/6 8:2 1/1/6 8:2 Average Summaries of rainfall events and the resulting discharges for MS1 are shown in Table 3 and Table 4. Average and maximum intensities are provided, as well as maximum stage and flow rates. Statistical summaries for MS1 for the monitoring seasons 2-26 are shown as box plots in figures 3-1. The 22 monitoring season recorded the largest increases in median values for total suspended solids, volatile suspended solids, total phosphorus, and total Kjedahl nitrogen. Further analysis of factors around this site is needed to fully understand why this occurred. Median values decline over the next four years for TSS, VSS, and TP. TKN maintains a stable trend from Total chloride ions for MS1 had a stable trend since the first year of monitoring in 23. Interestingly, the highest chloride results occurred during the first sample of each year. This points to a correlation to snowmelt and increased amounts of chloride being washed off the roads. Fecal Coliform statistical summary is difficult due to low numbers of samples, with the years 23 and 24 unable to perform tests because of these low numbers of samples. It should be noted that the geometric means of fecal coliform exceeds the numerical limits for water quality standards, however it does not violate the water quality standard due to the low amount of samples taken each year. The standard is as follows: Not to exceed 2 organisms per 1 milliliters as a geometric mean of not less than five samples in any calendar month, nor shall more than ten percent of all samples taken during any calendar month individually exceed 4 organisms per 1 milliliters. The standard applies only between April 1 and October 31. (Minnesota Pollution Control Agency. Waters of the State. Chapter 75, Subsection 222.). The box plots indicate further and more intensive E. Coli bacteria sampling to verify the flowing waters at MS1 are within the Minnesota Pollution Control Agency s water quality standards. The geometric mean for MS1 in 22 was 377 organisms per 1 ml, 25 was 555 organisms per 1 ml, and 26 was 343 organisms per 1 m/l. 1

11 Table 4. MS1 26 Storm Events MS 1 Storm Event Total Rainfall (in) Average Intensity (in/hr) Max Intensity (in) Max Storm Intensity Max Intensity (in/hr) Start End Days Storm # Start End Duration (days) Hr Duration (hr) Rainfall (in) 1 4/2/26 13:3 4/2/26 2: /2/26 19:3 4/2/26 2: /28/26 12:3 5/1/26 18: /29/26 16: 4/29/26 17: /8/26 16:3 5/8/26 17: /8/26 16:45 5/8/26 16: /8/26 22:15 5/8/26 23: /8/26 22:45 5/8/26 23: /12/26 3:3 5/12/26 19: /12/26 16: 5/12/26 16: /13/26 13:45 5/13/26 18: /13/26 16:45 5/13/26 16: /15/26 16: 5/15/26 18: /15/26 16: 5/15/26 16: /16/26 16: 5/16/26 17: /16/26 16: 5/16/26 16: /25/26 21: 5/25/26 22: /25/26 21:15 5/25/26 21: /29/26 18: 5/29/26 19: /29/26 19:3 5/29/26 19: /5/26 19:3 6/5/26 2: /5/26 19:45 6/5/26 19: /5/26 23:15 6/6/26 : /5/26 23:15 6/5/26 23: /16/26 2:45 6/17/26 : /16/26 22:15 6/16/26 22: /17/26 18:3 6/17/26 18: /17/26 18:3 6/17/26 18: /24/26 17:15 6/25/26 7: /24/26 21:45 6/24/26 22: /26/26 18:15 6/26/26 2: /26/26 2:15 6/26/26 2: /13/26 21:45 7/14/26 2: /13/26 22: 7/13/26 22: /16/26 7:45 7/16/26 9: /16/26 8:15 7/16/26 8: /19/26 9:45 7/19/26 16: /19/26 1: 7/19/26 1: /24/26 16:15 7/24/26 18: /24/26 18: 7/24/26 18: /1/26 1:45 8/2/26 8: /1/26 13: 8/1/26 13: /6/26 2:3 8/6/26 3: /6/26 2:3 8/6/26 2: /23/26 4:15 8/23/26 6: /23/26 4:15 8/23/26 4: /24/26 12:15 8/24/26 18: /24/26 15:15 8/24/26 15: /24/26 19: 8/24/26 19: /24/26 19: 8/24/26 19: /3/26 2:45 9/3/26 22: /3/26 15:45 9/3/26 16: /1/26 17: 9/1/26 18: /1/26 17: 9/1/26 17: /21/26 15: 9/22/26 2: /21/26 2:3 9/21/26 2: /23/26 15:45 9/23/26 2: /23/26 16:45 9/23/26 17: /11/26 3:15 1/11/26 8: /11/26 5:45 1/11/26 5: /16/26 5:45 1/16/26 14: /16/26 6: 1/16/26 6: Average Intensity (in/hr) Table 5. MS1 26 Storm Discharge Events MS1 Hydrograph Flow Rate (cfs) Stage (ft) Total Storm # Rainfall Total (in) Start End Discharge (cf) Max Time Start End Max Time Start End /2/26 13: 4/21/26 5: 49, /2/26 2: /2/26 2: /28/26 13: 5/2/26 11: 558, /3/26 1: /3/26 1: /8/26 16: 5/8/26 18: 9,4 3. 5/8/26 17: /8/26 17: /8/26 22: 5/9/26 4: 17, /8/26 23: /8/26 23: /12/26 5: 5/12/26 23: 89, /12/26 18: /12/26 18: /13/26 16: 5/13/26 22: 43, /13/26 17: /13/26 17: /15/26 14: 5/15/26 2: 13, /15/26 16: /15/26 17: /16/26 16: 5/16/26 23: 26, /16/26 16: /16/26 16: /25/26 21: 5/26/26 1: 6, /25/26 21: /25/26 21: /29/26 16: 5/3/26 6: 23, /29/26 19: /29/26 19: /5/26 19: 6/5/26 21: 11, /5/26 2: /5/26 2: /5/26 23: 6/6/26 2: 236, /6/26 : /6/26 : /16/26 21: 6/17/26 5: 33, /16/26 22: /16/26 22: /17/26 18: 6/17/26 2: 2, /17/26 19: /17/26 19: /24/26 15: 6/25/26 13: 35, /24/26 22: /24/26 22: /26/26 17: 6/27/26 1: 4, /26/26 2: /26/26 2: /13/26 22: 7/14/26 7: 6, /13/26 22: /13/26 22: /16/26 8: 7/16/26 15: 11, /16/26 9: /16/26 9: /19/26 1: 7/19/26 19: 32, /19/26 1: /19/26 1: /24/26 18: 7/24/26 23: 37, /24/26 18: /24/26 18: /1/26 3: 8/2/26 21: 775, /2/26 4: /2/26 4: /6/26 2: 8/6/26 6: 18, /6/26 2: /6/26 2: /23/26 4: 8/23/26 12: 65, /23/26 4: /23/26 4: /24/26 15: 8/24/26 18: 86, /24/26 15: /24/26 15: /24/26 18: 8/25/26 8: 469, /24/26 19: /24/26 19: /3/26 15: 9/4/26 7: 21, /3/26 16: /3/26 16: /1/26 17: 9/1/26 23: 13, /1/26 17: /1/26 17: /21/26 14: 9/23/26 15: 117, /21/26 21: /21/26 21: /23/26 15: 9/24/26 6: 56, /23/26 17: /23/26 17: /11/26 5: 1/11/26 17: 12, /11/26 6: /11/26 6: /16/26 5: 1/16/26 21: 2, /16/26 6: /16/26 6:

12 TSS mg/l Aggregate MS1 - TSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 296. Figure 3. MS1 Total Suspended Solids Box Plot (2-26) 12

13 TSS mg/l Aggregate MS1 - TSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 296. Figure 4. MS1 Total Suspended Solids Box Plot (2-26) without outliers 13

14 VSS mg/l Aggregate MS1 - VSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to 22. Figure 5. MS1 Total Volatile Suspended Solids Box Plot (2-26) 14

15 TP mg/l Aggregate MS1 - TP n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to.391 Figure 6. MS1 Total Phosphorus Box Plot (2-26) 15

16 TKN mg/l Aggregate MS1 - TKN n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 1.9 Figure 7. MS1 Total Kjedahl Nitrogen Box Plot (2-26) 16

17 Chloride Ions mg/l Aggregate MS1 - Chloride n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to 82. Figure 8. MS1 Total Chloride Ions Box Plot (23-26) 17

18 Chloride Ions mg/l Aggregate MS1 - Chloride n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to 82. Figure 9. Total Chloride Ions Box Plot (23-26) without Outliers 18

19 Fecal Coliform #/1 ml Aggregate MS1 - Fecal Coliform n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to - Figure 1. Fecal Coliform Box Plot (22-26) *not enough samples to complete statistical analysis for 23 and 24. *E. Coli bacteria was sampled for the 26 monitoring season, prior it was total fecal coliform 19

20 MS2 (Bailey) The hydrograph for the MS2 site shows flow from April 5 October 25, 26 (Figure 11). Total discharge during this period was 29,249,97 cf or 671 acre-ft. Peak discharge was 3.16 cfs on August 2, 26 from a storm totaling 3.68 inches of rainfall, the highest storm total for 26. MS2 26 Flow and Daily Rainfall Flow Rate Rainfall cfs 15 in May Jun Jul Aug Sep Oct 4/3/26 3:: PM - 1/25/26 8:: PM. Figure 11. MS2 26 Continuous Flow and Daily Rainfall 2

21 Table 6. MS2 Stream Loading Table Sample Collection Time Sample Type Storm # Start End TSS Interval Interval Interval TP Start End Volume (cf) TSS (lb) TP (lb) Base /1/26 : 3/28/26 : 1,857, Snowmelt Grab 3/31/6 14: 3/31/6 14: /28/26 : 4/1/26 : 2,73, Base /1/26 : 4/5/26 1:3 766, Base /5/26 1:3 4/6/26 11:3 243, Storm Composite 1 4/6/6 21:7 4/9/6 13: /6/26 11:3 4/13/26 5:3 5,574, Base /13/26 5:3 4/28/26 17:3 1,476, Storm /28/26 17:3 5/4/26 13:3 1,459, Base /4/26 13:3 5/8/26 12:3 1,458, Storm /8/26 12:3 5/11/26 8:3 73, Base /11/26 8:3 5/12/26 11:3 165, Base Composite 5/13/6 6:6 5/13/6 19: /12/26 11:3 5/16/26 14:3 1,799, Base /16/26 14:3 5/29/26 11:3 945, Storm /29/26 11:3 5/3/26 14:3 35, Base Grab 6/2/6 9:3 6/2/6 9: /3/26 14:3 6/5/26 21:3 87, Storm Composite 5 6/6/6 1:29 6/6/6 5: /5/26 21:3 6/7/26 8:3 147, Base /7/26 8:3 6/16/26 22:3 78, Storm /16/26 22:3 6/17/26 23:3 23, Base Composite 6/3/6 15:21 7/3/6 14: /17/26 23:3 7/19/26 1:3 68, Storm /19/26 1:3 7/21/26 1:3 45, Base /21/26 1:3 7/24/26 17:3 7, Storm /24/26 17:3 7/26/26 2:3 8, Base /26/26 2:3 8/1/26 12:3 2, Storm Composite 9 8/1/6 13:14 8/2/6 1: /1/26 12:3 8/3/26 5:3 1,587, Storm Composite 9 8/4/6 11:23 8/6/6 6: /3/26 5:3 8/8/26 1:3 5,88, Base /8/26 1:3 8/13/26 11:3 1,362, Storm /13/26 11:3 8/14/26 18:3 181, Base /14/26 18:3 8/23/26 4:3 249, Storm Grab 11 8/23/6 14:32 8/23/6 14: /23/26 4:3 8/24/26 1:3 12, Base /24/26 1:3 8/24/26 15:3 26, Storm Composite 12 8/24/6 22:14 8/26/6 7: /24/26 15:3 8/28/26 11:3 1,893, Base /28/26 11:3 9/3/26 15:3 1,36, Storm /3/26 15:3 9/9/26 5:3 1,736, Base Composite 9/12/6 12:6 9/13/6 4: /9/26 5:3 9/21/26 17:3 99, Storm /21/26 17:3 9/23/26 16:3 63, Storm /23/26 16:3 9/24/26 11:3 25, Base /24/26 11:3 1/25/26 13:3 33, No Flow. 1/25/26 13:3 1/1/27 :.. Storm Average Base Average Snowmelt Average All Average Loading Interval Total 33,945,185 23, SWWD Major Subwatershed Total Acres 1,174 Total TP/TSS(lb/ac/yr) Total TP/TSS (kg/ha/yr) *Italics indicate estimated concentrations based on average base and storm flow concentrations 21

22 Grab and flow weighted composite samples were taken at the MS2 site to determine water quality. Samples were taken during snowmelt and storm runoff, as well as during base flow conditions. The TSS, TKN, TP, VSS, COD, TDP, and E. Coliform results from all collected samples are listed in Table 7. Both the highest TSS and TP concentrations were collected in a base composite on September 12, 26. The highest TKN concentrations were collected in a storm composite on June 6, 26. Metals and other Nitrogen species chemical results are listed in Table 8. Table 7. MS2 26 Sample Chemistry Results Sample Type Start Date End Date TSS VSS TKN TP E. Coliform (#/1 ml) COD TDP Snowmelt Grab 3/31/6 14: 3/31/6 14: ~7 ~ Storm Composite 4/6/6 21:7 4/9/6 13:37 11 ~ ~.32 Base Composite 5/13/6 6:6 5/13/6 19: ~.16 Base Grab 6/2/6 9:3 6/2/6 9: ~.18 Storm Composite 6/6/6 1:29 6/6/6 5:14 NA NA E. Coli Grab 6/14/6 1:2 6/14/6 1:2 16 Base Composite 6/3/6 15:21 7/3/6 14: E. Coli Grab 7/25/6 9:45 7/25/6 9:45 5 Storm Composite 8/1/6 13:14 8/2/6 1:28 3 ~ Storm Composite 8/4/6 11:23 8/6/6 6: E. Coli Grab 8/1/6 9:3 8/1/6 9:3 18 Storm Grab 8/23/6 14:32 8/23/6 14: Storm Composite 8/24/6 22:14 8/26/6 7: E. Coli Grab 9/6/6 9: 9/6/6 9: 8 Base Composite 9/12/6 12:6 9/13/6 4: ~.3 Average Table 8. MS2 26 Sample Metals and Nitrogen Species Chemical Results Sample Type Start Date End Date Copper Nickel Lead Zinc Cadmium Chromium Chloride Nitrite N Nitrate N Nitrogen Snowmelt Grab 3/31/6 14: 3/31/6 14: < < Storm Composite 4/6/6 21:7 4/9/6 13: < Storm Composite 5/13/6 6:6 5/13/6 19: <.3 <.5.7 Base Grab 6/2/6 9:3 6/2/6 9: < <.3 <.5 ~.5 Storm Composite 6/6/6 1:29 6/6/6 5: <.2 E. Coli Grab 6/14/6 1:2 6/14/6 1:2 Base Composite 6/3/6 15:21 7/3/6 14: < E. Coli Grab 7/25/6 9:45 7/25/6 9:45 Storm Composite 8/1/6 13:14 8/2/6 1: < Storm Composite 8/4/6 11:23 8/6/6 6: <.3 <.5.14 E. Coli Grab 8/1/6 9:3 8/1/6 9:3 Storm Grab 8/23/6 14:32 8/23/6 14: < <.3 <.5 ~.2 Storm Composite 8/24/6 22:14 8/26/6 7: < E. Coli Grab 9/6/6 9: 9/6/6 9: Base Composite 9/12/6 12:6 9/13/6 4: <.3 <.5 <.2 Average

23 Summaries of rainfall events and the resulting discharges for MS2 are shown in Table 9 and Table 1. Average and maximum intensities are provided, as well as maximum stage and flow rates. Table 9. MS2 26 Storm Events MS2 Storm Event Total Rainfall (in) Average Intensity (in/hr) Max Intensity (in) Max Storm Intensity Max Intensity (in/hr) Start End Days Storm # Start End Duration (days) Hr Duration (hr) Rainfall (in) 1 4/6/26 15:45 4/6/26 21: /6/26 19:45 4/6/26 2: /28/26 12:45 5/1/26 19: /29/26 16:3 4/29/26 17: /8/26 16:15 5/8/26 23: /8/26 16:15 5/8/26 17: /29/26 18: 5/29/26 19: /29/26 18:15 5/29/26 19: /5/26 19:45 6/6/26 : /5/26 23:45 6/6/26 : /16/26 2:45 6/17/26 : /16/26 22:15 6/16/26 22: /19/26 1: 7/19/26 12: /19/26 1:15 7/19/26 1: /24/26 16:45 7/24/26 18: /24/26 18: 7/24/26 18: /1/26 2: 8/2/26 8: /1/26 2: 8/1/26 2: /13/26 12:3 8/13/26 15: /13/26 14:3 8/13/26 14: /23/26 4:15 8/23/26 6: /23/26 4:3 8/23/26 4: /24/26 11: 8/24/26 19: /24/26 17: 8/24/26 17: /3/26 15:45 9/3/26 21: /3/26 15:45 9/3/26 16: /21/26 13:3 9/22/26 17: /21/26 2:3 9/21/26 21: /23/26 16:15 9/23/26 2: /23/26 16:3 9/23/26 16: Average Intensity (in/hr) Table 1. MS2 26 Storm Discharge Events MS2 Hydrograph Flow Rate (cfs) Stage (ft) Total Storm # Rainfall Total (in) Start End Discharge (cf) Max Time Start End Max Time Start End /6/26 11:3 4/13/26 5:3 5,574, /9/26 13: /9/26 1: /28/26 17:3 5/4/26 13:3 1,459, /2/26 23: /2/26 2: /8/26 12:3 5/11/26 8:3 73, /1/26 7: /9/26 : /29/26 11:3 5/3/26 14:3 35, /29/26 22: /29/26 2: /5/26 21:3 6/7/26 8:3 147, /6/26 2: /6/26 2: /16/26 22:3 6/17/26 23:3 23, /17/26 8: /17/26 9: /19/26 1:3 7/21/26 1:3 45, /19/26 15: /19/26 14: /24/26 17:3 7/26/26 2:3 8, /25/26 7: /25/26 5: /1/26 12:3 8/8/26 1:3 6,675, /2/26 5: /2/26 5: /13/26 11:3 8/14/26 18:3 181, /13/26 18: /13/26 17: /23/26 4:3 8/24/26 1:3 12, /23/26 1: /23/26 9: /24/26 15:3 8/28/26 11:3 1,893, /27/26 4: /24/26 23: /3/26 15:3 9/9/26 5:3 1,736, /6/26 19: /8/26 8: /21/26 17:3 9/23/26 16:3 63, /22/26 19: /22/26 18: /23/26 16:3 9/24/26 11:3 25, /24/26 : /23/26 22: Statistical summaries of MS2 indicate that the pond is pre-treating water before discharging to Bailey Lake. Total suspended solids, volatile suspended solids, total phosphorus, and total Kjedahl nitrogen all are low in concentration. Total chloride ions had an increase in median values from 23 to 25, but results still show that the pond is pre-treating the water leaving the site. Similar results as MS1 for fecal coliform show that the number of samples taken are too few to draw any conclusions at this time. Figures show the statistical summaries in the form of box plots for MS2. 23

24 TSS mg/l Aggregate MS2 - TSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 16. Figure 12. MS2 Total Suspended Solids Box Plot (2-26) 24

25 7 6 5 TSS mg/l Aggregate MS2 - TSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 16. Figure 13. MS2 Total Suspended Solids Box Plot (2-26) without Outliers 25

26 VSS mg/l Aggregate MS2 - VSS n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to 12. Figure 14. MS2 Total Volatile Suspended Solids Box Plot (2-26) 26

27 TP mg/l Aggregate MS2 - TP n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to.31 Figure 15. MS2 Total Phosphorus Box Plot (2-26) 27

28 TP mg/l Aggregate MS2 - TP n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to.31 Figure 16. MS2 Total Phosphorus Box Plot (2-26) without Outliers 28

29 TKN mg/l Aggregate MS2 - TKN n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to to to to to 1.8 Figure 17. MS2 Total Kjedahl Nitrogen Box Plots (2-26) 29

30 Chloride Ions mg/l Aggregate MS2 - Chloride n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to 64. Figure 18. MS2 Total Chloride Ions Box Plot (23-26) 3

31 25 2 Fecal Coliform #/1 ml Aggregate MS2 - Fecal Coliform n Mean SD SE 95% CI of Mean Median IQR 95% CI of Median Aggregate to to to to to to to to to to to to - Figure 19. MS2 Fecal Coliform Box Plot (22-26) *E. Coli bacteria was sampled for the 26 monitoring season, prior it was total fecal coliform 31

32 Powers Lake East Tributary The hydrograph for the Powers Lake site shows flow between April 13-October 25, 26 (Figure 2). Precipitation was logged between May 23-October 25, 26. Total discharge during this period was 4,932,268 cf or 113 acre/ft. The highest discharge 9.46 cfs occurred on August 2, 26 from a total rainfall of 2.72 inches, which fell from August 1, 26-August 2, 26. This total rainfall was the highest for the 26 monitoring season. Powers 26 Flow and Daily Rainfall 9 Flow Rate Rainfall cfs.3 in May Jun Jul Aug Sep Oct 4/12/26 7:: AM - 1/26/26 1:: PM. Figure 2. Powers Lake East Tributary 26 Flow and Daily Rainfall 32

33 Grab and flow weighted composite samples were taken at the Powers site in 26. The TSS, TKN, TP, VSS, COD, TDP, and E. Coliform results from all collected samples are listed in Table 11. The highest TSS concentration of 21 mg/l was from an August 1, 26 base composite sample. TKN concentrations had a range of.46 to 2.8 mg/l, with the highest concentration coming from the September 3, 26 storm composite sample. The highest TP concentration (.737 mg/l) was also from the September 3, 26 storm composite sample. Metals and other Nitrogen species chemical results are listed in Table 12. Table 11. Powers Lake East Tributary 26 Sample Chemistry Results Sample Type Start Date End Date TSS VSS TKN TP E. Coliform (#/1 ml) COD TDP Snowmelt Grab 3/31/6 14:15 3/31/6 14:15 2 ~ ~.34 Base Grab 5/16/6 1:45 5/16/6 1:45 ~2 ~2.72 ~ ~.16 Base Grab 5/3/6 1: 5/3/6 1: ~1 ~2.46 ~ Base Grab 6/6/6 1:48 6/6/6 1:48 3 ~2.56 ~ <.1 Base Grab 7/5/6 9:39 7/5/6 9:39 ~3 ~ E. Coli Grab 7/25/6 9:3 7/25/6 9:3 242 Storm Composite 8/1/6 21:7 8/2/6 15:29 14 ~ ~.32 E. Coli Grab 8/1/6 1: 8/1/6 1: 73 Base Composite 8/1/6 1:19 8/1/6 14: ~.39 Storm Composite 8/24/6 15:36 8/24/6 16:31 17 ~ ~.33 Storm Composite 9/3/6 15:44 9/3/6 16:3 NA NA ~.28 E. Coli Grab 9/6/6 9:15 9/6/6 9:15 54 E. Coli Grab 9/1/6 8:45 9/1/6 8:45 39 Base Grab 9/12/6 9:46 9/12/6 9:46 ~1 ~ ~.3 Average Table 12. Powers Lake East Tributary 26 Sample Metals and Nitrogen Species Chemical Results Sample Type Start Date End Date Copper Nickel Lead Zinc Cadmium Chromium Chloride Nitrite N Nitrate N Nitrogen Snowmelt Grab 3/31/6 14:15 3/31/6 14: < <.3.7 <.2 Base Grab 5/16/6 1:45 5/16/6 1: <.7.46 < <.3 <.5 <.2 Base Grab 5/3/6 1: 5/3/6 1: < <.3.52 <.2 Storm Grab 6/6/6 1:48 6/6/6 1: < <.3.8 <.2 Base Grab 7/5/6 9:39 7/5/6 9: E. Coli Grab 7/25/6 9:3 7/25/6 9:3 Storm Composite 8/1/6 21:7 8/2/6 15: <.3 <.5 <.2 E. Coli Grab 8/1/6 1: 8/1/6 1: Storm Composite 8/1/6 1:19 8/1/6 14: <.3 <.5 ~.2 Storm Composite 8/24/6 15:36 8/24/6 16: < Storm Composite 9/3/6 15:44 9/3/6 16:3 E. Coli Grab 9/6/6 9:15 9/6/6 9:15 E. Coli Grab 9/1/6 8:45 9/1/6 8:45 Base Grab 9/12/6 9:46 9/12/6 9: <.3.26 <.2 Average

34 Summaries of rainfall events and the resulting discharges for Powers Lake East Tributary are shown in Table 13 and Table 14. Average and maximum intensities are provided, as well as maximum stage and flow rates. Table 13. Powers Lake East Tributary 26 Storm Events Powers Storm # Start End Storm Event Duration (days) Hr Total Rainfall (in) Average Intensity (in/hr) Max Intensity (in) Max Intensity (in/hr) Max Storm Intensity Start End Days Duration (hr) 1 4/28/26 12:45 5/1/26 6: /29/26 16:45 4/29/26 17: /8/26 16:15 5/8/26 17: /8/26 16:3 5/8/26 17: /8/26 22:15 5/8/26 23: /8/26 23: 5/8/26 23: /12/26 4:45 5/12/26 19: /12/26 16:3 5/12/26 17: /25/26 19:3 5/25/26 21: /25/26 2: 5/25/26 2: /29/26 16:45 5/29/26 18: /29/26 17:3 5/29/26 17: /1/26 4: 6/1/26 5: /1/26 4: 6/1/26 4: /5/26 18:15 6/5/26 23: /5/26 22: 6/5/26 22: /16/26 2:45 6/17/26 4: /16/26 22:15 6/16/26 22: /18/26 17:15 6/18/26 17: /18/26 17:15 6/18/26 17: /24/26 1: 6/25/26 7: /24/26 21:45 6/24/26 22: /26/26 18:3 6/26/26 21: /26/26 2:3 6/26/26 2: /13/26 22: 7/14/26 2: /13/26 22:15 7/13/26 22: /16/26 8:3 7/16/26 1: /16/26 8:3 7/16/26 8: /19/26 1: 7/19/26 12: /19/26 1: 7/19/26 1: /24/26 16:15 7/24/26 18: /24/26 16:3 7/24/26 16: /1/26 3:3 8/2/26 8: /1/26 12:15 8/1/26 13: /6/26 2:15 8/6/26 4: /6/26 2:3 8/6/26 2: /13/26 14:3 8/13/26 15: /13/26 14:3 8/13/26 14: /23/26 4:15 8/23/26 6: /23/26 4:15 8/23/26 4: /24/26 12:45 8/24/26 2: /24/26 19: 8/24/26 19: /28/26 9:45 8/28/26 11: /28/26 11:15 8/28/26 11: /3/26 15:3 9/3/26 2: /3/26 15:45 9/3/26 16: /1/26 17: 9/1/26 18: /1/26 17: 9/1/26 17: /17/26 4:45 9/17/26 9: /17/26 6:15 9/17/26 6: /21/26 15:45 9/22/26 18: /22/26 7:3 9/22/26 8: /23/26 16: 9/23/26 2: /23/26 16: 9/23/26 16: /3/26 22:15 1/3/26 22: /3/26 22:15 1/3/26 22: /11/26 3:3 1/11/26 7: /11/26 5:45 1/11/26 5: /16/26 5:45 1/16/26 14: /16/26 6: 1/16/26 6: /18/26 11:45 1/18/26 12: /18/26 12:15 1/18/26 12: Rainfall (in) Average Intensity (in/hr) 34

35 Table 14. Powers Lake East Tributary 26 Storm Discharge Events Powers Hydrograph Flow Rate (cfs) Stage (ft) Total Storm # Rainfall Total (in) Start End Discharge (cf) Max Time Start End Max Time Start End /28/26 1:45 5/3/26 18:45 396, /1/26 12: /2/26 18: /8/26 14:45 5/8/26 16:45 4, /8/26 15: /8/26 15: /8/26 19:45 5/9/26 :45 18, /8/26 21: /8/26 21: /12/26 1:45 5/14/26 15:45 95, /13/26 1: /13/26 1: /25/26 18:45 5/26/26 1:45 2, /25/26 2: /25/26 2: /29/26 16:45 5/29/26 19:45 1, /29/26 18: /29/26 18: /1/26 3:45 6/1/26 5: /1/26 4: /1/26 4: /5/26 17:45 6/6/26 :45 14, /5/26 22: /5/26 22: /16/26 2:45 6/17/26 6:45 4, /16/26 22: /16/26 22: /18/26 16:45 6/18/26 2:45 1, /18/26 17: /18/26 17: /24/26 9:45 6/25/26 1:45 8, /24/26 22: /24/26 22: /26/26 17:45 6/26/26 23:45 1, /26/26 2: /26/26 2: /13/26 21:45 7/14/26 4:45 2, /13/26 22: /13/26 22: /16/26 6:45 7/16/26 12:45 1, /16/26 9: /16/26 9: /19/26 9:45 7/19/26 13:45 5, /19/26 1: /19/26 1: /24/26 15:45 7/24/26 21:45 5, /24/26 16: /24/26 16: /1/26 11:45 8/3/26 19:45 1,2, /2/26 8: /2/26 4: /6/26 1:45 8/6/26 13:45 45, /6/26 3: /6/26 2: /13/26 13:45 8/15/26 2:45 46, /13/26 14: /13/26 14: /23/26 3:45 8/23/26 8:45 6, /23/26 4: /23/26 4: /24/26 14:45 8/27/26 5:45 563, /25/26 1: /24/26 19: /28/26 1:45 8/28/26 14:45 7, /28/26 12: /28/26 11: /3/26 14:45 9/3/26 17:45 14, /3/26 16: /3/26 16: /1/26 13:45 9/1/26 19:45 3, /1/26 17: /1/26 17: /17/26 5:45 9/17/26 7: /17/26 6: /17/26 6: /21/26 13:45 9/23/26 15:45 51, /23/26 11: /23/26 11: /23/26 15:45 9/25/26 1:45 158, /24/26 2: /23/26 19: /3/26 21:45 1/4/26 1: /3/26 22: /3/26 22: /11/26 3:45 1/11/26 9:45 1, /11/26 4: /11/26 4: /16/26 4:45 1/16/26 15:45 1, /16/26 6: 1E /16/26 6: /18/26 11:45 1/18/26 16: /18/26 12: /18/26 12: Box plots for Powers Lake East Tributary for 24 to 26 are in figures Total suspended solids, volatile suspended solids, total phosphorus, and total Kjedahl nitrogen all have median values decreasing over time and variability within the box plot decreasing as well. For all parameters, large decreases in concentrations are occurring between years. Such decreases may be attributed to the large amount of construction in the nearby development during the early monitoring seasons. Further erosion and sediment control over the last couple years combined with vegetation and cover establishment may be contributing to lower concentrations observed. Further analysis of different possible factors within the drainage area will be needed to fully understand both the large decreases and for such high results in 24. Total chloride ions median values have an increasing trend over the past three monitoring seasons. These increases maybe contributed to the establishment of roads and salt applications in recent constructed developments. Fecal coliform samples are too few to draw statistical conclusions between monitoring seasons. 35