water quality monitoring strategy -...

Water Quality Monitoring

For the

South Slopes

of the

JOE RICH CREEK WATERSHED

(Year 3 - 2002 Data)

Prepared forGORMAN BROS. LUMBER LTD.

Westbank, BC

byDOBSON ENGINEERING LTD.

#4, 1960 Springfield RoadKelowna, BC

V1Y 5V7

March, 2003

Water Quality Monitoring / Joe Rich Creek Watershed (Year 3 – 2002) i

File: 505-016 Project: 22046 Date: March 2003 DOBSON ENGINEERING LTD.

Table of Contents

1.0 INTRODUCTION.................................................................................................................. 1

2.0 PROJECT DESCRIPTION .................................................................................................. 1

2.1 WATER QUALITY PARAMETERS............................................................................................. 2

2.2 SAMPLING METHODS/EQUIPMENT......................................................................................... 2

2.3 SAMPLING LOCATIONS .......................................................................................................... 3

2.4 SAMPLING DATES .................................................................................................................. 3

2.5 QUALITY ASSURANCE AND QUALITY CONTROL.................................................................... 4

2.6 PRECIPITATION AND STREAM DISCHARGE............................................................................. 5

3.0 LABORATORY ANALYSIS RESULTS ............................................................................ 5

3.1 TURBIDITY............................................................................................................................. 6

3.2 SUSPENDED SOLIDS ............................................................................................................... 7

4.0 FOREST DEVELOPMENT ................................................................................................. 8

4.1 PAST FOREST DEVELOPMENT ................................................................................................ 8

4.2 PROPOSED FOREST DEVELOPMENT........................................................................................ 9

5.0 CONCLUSIONS .................................................................................................................... 9

6.0 RECOMMENDATIONS..................................................................................................... 11

Water Quality Monitoring / Joe Rich Creek Watershed (Year 3 – 2002) ii


Tables

Table 1Sampling Site Locations and EMS Identification Numbers

Table 2Sampling Dates and Parameters Analyzed

Table 3Turbidity Values – Clear Flow Vs Turbid Flow (2000-2002)

Table 4Suspended Solids Values – Clear Flow Vs Turbid Flow (2000-2002)

Table 5Proposed Forest Development

Water Quality Monitoring / Joe Rich Creek Watershed (Year 3 – 2002) iii


APPENDICES

APPENDIX AWater Quality Monitoring Sites – Location Map

APPENDIX BLab Analysis Data – Tables 1-3

APPENDIX CPrecipitation and Stream Discharge Data


GORMAN BROS. LUMBER LTD.Westbank, BC

Water Quality Monitoring for theSouth Slopes

of theJOE RICH CREEK WATERSHED

(Year 3 - 2002 Data)

1.0 INTRODUCTION

This report discusses the water quality assessment for Leech, Schram and Bailey Creeks,which are situated on the south slopes of the Joe Rich Creek watershed. The Joe RichWatershed Monitoring Group has expressed concerns about the proposed forestdevelopment by Gorman Bros. Lumber Ltd. in this area and the potential impacts thedevelopment may have on water quality. The purpose of this program is to determine ifforest development is affecting water quality in the above named creeks by comparing waterquality in basins with active development to water quality in those that do not.

2.0 PROJECT DESCRIPTION

This project is designed as a paired watershed study using Leech Creek as a control basin,and Schram Creek and Bailey Creeks as treatment basins (Refer to Appendix A, LocationMap). Leech Creek was to remain un-harvested, however, forest management issuesresulted in the harvest of a small patch cut area in upper Leech Creek (Polygon 1966 - CP401, FL A18671 ~ 10 ha). This development is not intensive, and this basin remains usefulas a control for the study. There is currently no future development proposed in LeechCreek.

The Schram Creek basin is currently undeveloped, allowing its use as a control basin aswell, however there is future development proposed in Schram Creek. Proposeddevelopment is discussed in detail in Section 4.0.

Water quality sampling was conducted from 2000 – 2002 to determine if forest developmentis affecting water quality (primarily sediment dynamics – turbidity/suspended solids).Residents in the area (Jules and Matt Morris) collected the water samples and deliveredthem to Caro Environmental Services for laboratory analyses. Gorman Bros. Lumber Ltd.has been operating in the area during the project period.

Water Quality Monitoring / Joe Rich Creek Watershed (Year 3 – 2002) 2


2.1 Water Quality Parameters

Water samples were collected and analyzed for turbidity and suspended solids duringeach site visit. These two parameters can be impacted by forest development as a resultof surface erosion from roads and landslides1.

During 2001, additional laboratory analyses were conducted for; alkalinity, calcium(total), chloride, color (true), dissolved solids (total), fluoride, hardness (total), iron(total), magnesium (total), manganese (total), nitrate, nitrite, pH, potassium (total),sodium (total), specific conductance, sulphate, uranium, total coliform and fecalcoliform. These parameters are typically examined for new drinking water sources,therefore they are no longer measured in this study. Although these additionalparameters are important with respect to drinking water quality, turbidity andsuspended solids best identify changes in water quality that result from surface erosion.

2.2 Sampling Methods/Equipment

Water sampling was conducted according to Resource Inventory Commission (RIC)standards as described in the Ambient Freshwater and Effluent Sampling Manual(Water Quality Branch, 1994).

Samples that were analyzed for turbidity and suspended solids were collected in cleanone-liter plastic bottles. Samples were placed in an insulated cooler and delivered toCaro Environmental Services for laboratory analysis. Jules Morris and Matt Morrisfrom the Joe Rich community collected and delivered the samples to the lab after eachsample collection.

1 MacDonald, L.H., A.W. Smart and R.C. Wissmar. 1991. Monitoring Guidelines to Evaluate Effects of ForestryActivities on Streams in the Pacific Northwest and Alaska.



2.3 Sampling Locations

The sampling site locations were chosen to provide water samples that arerepresentative of the study basins. Access concerns were also addressed during siteselection. Refer to Table 1 and the location map (Appendix A) for sampling sitelocations.

TABLE 1Sampling Site Locations and EMS* Identification Numbers

Site Location Co-ordinates EMS I.D.Number

Site #1Leech Creek

Leech Creek near the boundarybetween private land and Crown land,approximately 10m upstream fromthe water well.

49o 51' 42''N119o 09' 00''W

E243995

Site #2Schram Creek

Schram Creek immediately upstreamfrom the boundary between privateland and Crown land.

49o 50' 57''N119o 07' 09''W

E243996

Site #3Bailey Creek

Bailey Creek near the boundarybetween private land and Crown land,approximately 3m upstream from theDump road crossing.

49o 50' 25''N 119 o 06' 03''W

E243997

* Environmental Monitoring System – a provincial database for discrete sampling data.

Prior to July 20, 2001 water samples were collected at different locations than thosedescribed above. At Leech Creek, samples were collected approximately 2mdownstream from the water well rather than 10m upstream from the well. At SchramCreek, samples were collected within private property rather than immediately upstreamfrom the private property boundary, and at Bailey Creek, samples were collecteddownstream from the road crossing rather than 3m upstream from it.

2.4 Sampling Dates

The greatest range in water quality variability typically occurs during the spring freshetperiod (April through June). Samples were collected weekly from April 27, 2002 toJune 11, 2002 to characterize water quality during this time. Water quality variability istypically less outside of the spring freshet period, so samples were collected monthlyfrom July to October to characterize water quality during this time. Samples fromLeech Creek and Schram Creek were collected on 13 occasions, however due todifficult access in April and May, samples from Bailey Creek were collected 8 times.Refer to Table 2 for sample dates.



TABLE 2Sampling Dates and Parameters Analyzed (Including QA/QC Samples)

Sampling Dates Parameters AnalyzedApril 27, 2002* Suspended Solids, TurbidityMay 5, 2002* Suspended Solids, TurbidityMay 12, 2002* Suspended Solids, TurbidityMay 22, 2002* Suspended Solids, Turbidity Co-located Triplicates & Trip BlankMay 24, 2002 Suspended Solids, TurbidityMay 27, 2002* Suspended Solids, TurbidityJune 2, 2002 Suspended Solids, TurbidityJune 11, 2002 Suspended Solids, Turbidity Co-located Triplicates & Trip BlankJuly 2, 2002 Suspended Solids, TurbidityJuly 28, 2002 Suspended Solids, TurbidityAugust 26, 2002 Suspended Solids, Turbidity Co-located Triplicates & Trip BlankSeptember 22, 2002 Suspended Solids, TurbidityOctober 6, 2002 Suspended Solids, Turbidity

*Bailey Creek not sampled due to difficult access.

Dobson Engineering Ltd. staff collected the samples on May 24, 2002. Rain had beenfalling steadily since May 20, resulting in elevated stream flows. The occurrence of therainy period prompted the unscheduled water sample collection from the nearby studystreams.

2.5 Quality Assurance and Quality Control

Water sampling was conducted according to Resource Inventory Commission (RIC)standards as described in the Ambient Freshwater and Effluent Sampling Manual(Water Quality Branch, 1994). Most of the samples collected were delivered to thelaboratory within 24 hours of collection and were maintained at or below 10 �C.

Triplicate samples were collected on three occasions to determine the precision of thelaboratory analysis. The Ministry of Environment, Lands and Parks Guidelines forInterpreting Water Quality Data (1998) discuss the use of replicate samples as a checkfor laboratory precision. When triplicate samples are taken, precision is expressed aspercent relative standard deviation. For triplicates, a percent relative standard deviationof 18% or less is considered acceptable precision. With the exception of suspendedsolids values on June 11, 2002 the triplicates collected during this study period met thequality control criterion (Refer to Appendix B). The Guidelines for Interpreting WaterQuality Data states that in order to use Relative % Standard Deviation as a precisioncheck, the analytical values must be at least five times the Method Detection Limit(MDL). In the case where suspended solids appears to be imprecise, the labmeasurements were not five times the MDL and therefore the precision for suspendedsolids on these dates cannot be confirmed.



In addition to triplicate samples, blank samples were submitted to the laboratory. Ablank sample is a bottle filled with certified de-ionized water (provided by thelaboratory). This bottle is brought to each site and is exposed to the same conditions asthe actual sample (except it is not immersed in the creeks). Blank samples are used todetect contamination of the bottles, sampling gear, preservatives, filtering gear,atmosphere at the sampling location, handling by the collector either at the point ofsampling or during travel, and contamination at the lab. The Guidelines for InterpretingWater Quality Data (1998) indicate that contamination has occurred when 5% or moreof the blanks show any levels above the method detection limit. If the blanks are withinthe guidelines, the samples are considered uncontaminated and the data is consideredclean. Field blank analysis indicated no sample contamination.

Water samples were sent to a registered laboratory (Caro Environmental Services)under the Environmental Data Quality Assurance (EDQA) program to ensure dataaccuracy.

2.6 Precipitation and Stream Discharge

Intense rainfall, and rain on snow events in the spring, can result in rapid increases insurface run-off and streamflow. The increased surface run-off and increased stream flowcan cause increased turbidity and increased suspended sediment concentrations.

Environment Canada data indicates that in 2002, the Southern BC Mountains Regionexperienced the 2nd wettest spring on record since 1948 (Appendix C –Precipitation andStream Discharge Data). Water Survey of Canada data for Mission Creek indicates themaximum daily discharge for 2002 occurred on May 22, 2002 and was 59 m3/s. Thisequates to a 4 year peak flow event. Dobson Engineering Ltd. staff maintained generalnotes on weather conditions during the spring of 2002. Observations indicate steady rainin the Okanagan, (snow above approx. 1600 m) from the morning of May 20, 2002 tothe afternoon of May 23, 2002. Mission Creek and its tributaries (including the studystreams) all experienced elevated stream flows resulting from the sustained rainfall andsnowmelt.

In contrast to the very wet spring period, the summer and fall of 2002 were the 4th and7th driest periods on record since 1948.

3.0 LABORATORY ANALYSIS RESULTS

All water samples were sent to Caro Environmental Services for analysis. Samples wereroutinely analyzed for turbidity and suspended solids. Results of laboratory analyses havebeen entered in Environmental Monitoring System (EMS) – the provincial data base forwater quality data. The following sections provide a summary of the laboratory analysisresults and Tables 1 to 3 in Appendix B provide the detailed results.



3.1 Turbidity

Turbidity is a measurement that describes the “cloudiness” of water. Suspendedparticles in water cause incoming light to scatter and give water a cloudy appearance.The suspended particles can include clay, silt, fine sand, decaying organics, algae, andother micro-organisms. In the context of domestic water, turbidity is important assuspended particles can impair the effectiveness of various disinfection processes and isaesthetically displeasing. In many BC interior streams, spring freshet and rain eventsbring with them sediment laden water, which cause peaks in turbidity levels. HealthCanada’s guideline for drinking water that does not receive treatment to removeturbidity is a maximum of 1 NTU (nephelometric turbidity units). The acceptableturbidity level for raw water that is chlorinated is � 5 NTU if it can be demonstrated thatdisinfection is not compromised by the use of the less stringent value.

In snowmelt dominated watersheds, turbidity tends to be higher during the springfreshet period mainly as a result of increased stream flows. In the Joe Rich Creekwatershed the spring freshet, resulting from snowmelt in the upper elevations, typicallyoccurs from April to June. Based on this information the turbidity data has been dividedinto two separate periods: clear flow period and turbid flow period. The turbid flowperiod coincides with spring freshet between April 1 to June 30 with the clear flowperiod occurring during the remainder of the year. In 2002, turbidity was sampled 13times at Leech Creek and Schram Creek and 8 times at Bailey Creek. The turbidity datais arranged by flow period in Table 3.

Table 3Turbidity Values – Clear Flow vs Turbid Flow (2000-2002)

Clear Flow Period (July 1 – March 31)

Turbid Flow Period (April 1 – June 30)

Year # OfSamples

Range(NTU)

Mean(NTU)

# OfSamples

Range(NTU)

Mean(NTU)

Site #1 Leech Creek2000 8 0.20 – 1.40 0.70 8 2.7 – 11.0 6.432001 4 0.45 – 1.90 0.95 6 1.5 – 13.0 5.002002 5 0.25 – 0.70 0.42 8 1.70 – 75.0 14.5

Site #2 Schram Creek2000 5 0.55 – 1.90 1.08 8 1.7 – 12.0 6.342001 4 0.35 – 1.60 0.80 6 2.0 – 16.0 6.502002 5 0.30 – 0.65 0.49 8 1.8 – 68.0 16.7

Site #3 Bailey Creek2000 5 0.60 – 1.40 1.03 8 1.1 – 14.0 7.582001 4 0.55 – 2.80 1.26 6 2.8 – 16.0 7.502002 5 0.20 - 0.85 0.41 3 2.5 – 21.0 9.5

During the 2002 turbid flow period, all the turbidity values at all three sites exceededthe 1 NTU guideline. The maximum turbidity values at Leech and Schram Creeks were



recorded on May 22, 2002, however, Bailey Creek was not sampled on this date due toaccess difficulty. All three creeks were sampled two days later (May 24) and turbidityvalues were still elevated. It is likely that the turbidity at Bailey Creek on May 22 wasproportionately elevated with the turbidity in the other two streams on the same date.

The period in which turbidity values were elevated coincides with the extended rainfallperiod (May 20 – May 23, 2002). The increased turbidity appears to be independent ofthe levels of forest development in each of the sub-basins. Prior to 2002, turbidity datawas not captured during or immediately after extended rain periods.

None of the turbidity values exceeded the guideline during the 2002 clear flow period.The maximum and mean turbidity values in the 2002 clear flow period are the lowestrecorded since 2000. These relatively low values may in part be due to the lowprecipitation amounts during the summer and fall of 2002.

3.2 Suspended Solids

Suspended solids are reported as milligrams/litre (mg/l) and refer to the concentration ofsuspended solid material in the water. Suspended solids contribute directly to turbidityand can interfere with disinfection processes in drinking water, however there is noguideline for suspended solids in raw untreated drinking water. Suspended solids weremeasured on the same dates as turbidity and this data has also been separated into twoflow periods. The suspended solids data is arranged by flow period in Table 4.

Table 4Suspended Solids Values – Clear Flow vs Turbid Flow (2000-2002)

Clear Flow Period (July 1 – March 31)

Turbid Flow Period (April 1 – June 30)

Year # OfSamples

Range(mg/l)

% BDL* # OfSamples

Range(mg/l)

% BDL*

Site #1 Leech Creek2000 8 <1 – 4.0 50% 8 1.0 – 10.0 0%2001 4 All <1.0 100% 6 <1.0 – 3.0 17%2002 5 <1 – 1.0 80% 8 <1 - 191 25%

Site #2 Schram Creek2000 5 <1 – 4.0 60% 8 1.0 – 8.0 0%2001 4 <1.0 – 1.0 75% 6 <1.0 – 4.0 17%2002 5 All <1 100% 8 <1 - 145 25%

Site #3 Bailey Creek2000 5 <1 – 1.0 60% 8 1.0 – 12.0 0%2001 4 All <1.0 100% 6 <1.0 – 4.0 33%2002 5 All <1.0 100% 3 <1 – 44.0 66%

*% BDL = number of results Below Detection Limit (<1 mg/L), expressed as a percent of the data set.



The maximum suspended solids values for 2002 occurred during the rainy period inMay, and coincide with the maximum turbidity values, however the suspended solidsvalues do not correlate with low level turbidity values (<10 NTU). A correlationbetween suspended solids and turbidity does appear to exist when turbidity values aregreater than 10 NTU.

4.0 FOREST DEVELOPMENT

Gorman Bros. Lumber Ltd. is the forest licensee operating in the study area. Recent activityincludes development of polygon 1966 (CP 401, FL A18671 ~ 10 ha), located in the LeechCreek sub-basin and polygon 1988 (CP405, FL A18671 ~ 8.9 ha net patch cut, 32 ha grossarea), located in the Bailey Creek sub-basin. There has been no recent development in theSchram Creek sub-basin. Future forest development is proposed in the study area.

4.1 Past Forest Development

2000The access road construction and right of way logging for polygon 1966 commenced onAugust 1, 2000 and was completed on September 22, 2000. During this work period,several measures were utilized to minimize sediment production from the access road.These measures included placing straw bales and energy dissipaters in the ditches,installing culverts to maintain natural drainage and grass seeding all exposed soils.Harvesting of polygon 1966 commenced in 2001.

2001Polygon 1966 (CP 401, FL A18671 ~ 10 ha), located in the Leech Creek sub-basin, washarvested as a group selection polygon with removal of approximately 1/3 of the area.Harvesting of polygon 1966 commenced on January 29, 2001 and was shutdown onMarch 9, 2001 due to road load limit restrictions. During September 2001, the accessroad was surfaced with coarse material to reduce potential running surface erosion, andharvesting of polygon 1966 was completed by December 15, 2001.

Polygon 1988 (CP405, FL A18671 ~ 8.9 ha net patch cut, 32 ha gross area), located inthe Bailey Creek sub-basin, was accessed via existing roads. Reactivation andreconstruction of these roads commenced in December 2001 and harvesting wascompleted by February 20, 2002.

2002Harvest of polygon 1988 was completed in 2002 as noted above. Additional forestdevelopment was limited to road deactivation (routine cross ditch and water barconstruction). The access road to Bailey Creek was closed during the spring of 2002 dueto environmental concerns (soft roadbed conditions). During the sample collection onMay 24, 2002 (foot access only) DEL staff did not observe any sediment delivery fromthe roads to the streams.



4.2 Proposed Forest Development

Proposed forest development in the area is identified in Table 5 below. The dates for theproposed development are for planning purposes only, and are not critical, as defined inGorman Bros. Lumber Ltd. 2002-2007 Forest Development Plan.

Table 5Proposed Forest Development

CP and Block Basin Year Total Area (ha) Total Volume (m3) Silviculture System403-1 Schram 2003 28.7 8,612 Clear-cut403-2 Schram 2003 4.8 359 Partial-cut403-3 Schram 2003 23.0 6,911 Clear-cut404-1 Bailey 2004 10.4 3,129 Clear-cut406-5 Schram 2005 89.6 8,962 Partial-cut406-6 Bailey 2005 124.2 12,417 Partial-cut406-7 Bailey 2005 21.3 6,397 Clear-cut

5.0 CONCLUSIONS

� To better isolate the potential forest development related water quality influences,sample site locations were moved on July 20, 2001. Prior to July 20, 2001, Leech Creeksamples were collected approximately 2 m downstream from the water well rather thanthe current location (10 m upstream from the well). At Schram Creek, samples werecollected within private property rather than immediately upstream from the privateproperty boundary, and at Bailey Creek, samples were collected downstream from theroad crossing rather than 3m upstream from it.

� Water quality at the initial site locations was possibly influenced by additional factorsthan at the current site locations. For this reason, it is difficult to compare results prior toJuly 20, 2001 with those after that date.

� The current sampling schedule is designed to balance data integrity with project costs.Temporal water quality variability will be better identified with several years of datacollection.

� A recommendation from the 2001 report (limit the parameters to include only turbidityand suspended solids) was incorporated in 2002.

� In 2002, the Southern BC Mountains region experienced the 2nd wettest spring on recordsince 1948. The summer and fall of 2002 were the 4th and 7th driest on record.

� Intense rainfall, and rain on snow events in the spring, can result in rapid increases insurface run-off and stream flow. The increased surface run-off and increased stream flowcan cause increased turbidity and increased suspended solids concentrations.



� The maximum turbidity and suspended solids values recorded to date occurred during anextended rainfall period (May 20-23, 2002). All three study creeks experiencedincreased stream flow, turbidity and suspended solids resulting from the rainfall event.During the 2000, 2001 and 2002 turbid flow periods, all the turbidity values at all threesites exceeded the 1 NTU guideline.

� The maximum and mean turbidity and suspended solids values during the 2002 clearflow period were the lowest recorded since 2000. This may in part be due to therelatively low precipitation and stream flow in the summer and fall of 2002. None of theturbidity values exceeded the guidelines on any occasion during the clear flow period.

� In general, turbidity and suspended solids concentrations peak during the onset of thespring freshet, and as turbidity increases, so does suspended solids. The maximumsuspended solids values occurred on the same dates as did the maximum turbidityvalues, however, suspended solids values do not correlate strongly with low levelturbidity values (less than 10 NTU). A stronger correlation exists between the twoparameters when turbidity values are higher than 10 NTU.

� Although the maximum turbidity and suspended solids values recorded to date occurredin 2002, the values were nearly equal in all three basins regardless of the level of forestdevelopment. It is likely that the steady rainfall in May caused the increased turbidityand suspended solids values. The monitoring completed to date does not indicate forestdevelopment related changes in water quality.



6.0 RECOMMENDATIONS

� Water quality monitoring at the three sites should continue through 2003 since GormanBros. Lumber Ltd. has further proposed forest development in the watershed, andadditional data collection is required to better identify the temporal water qualityvariability in the study streams. If desired, continuing this project through 2003 can befunded through the Forest Investment Account (FIA).

� Sampling should continue on a weekly basis during freshet and on a monthly basisduring the summer and fall, however an effort should be made to sample within 24 hoursof a late summer/fall rainstorm event.

� The list of monitoring parameters should be limited to turbidity and suspended solids,and suspended solids analysis should only be conducted when turbidity values aregreater than 10 NTU.

� Although fecal coliform analyses are no longer conducted as part of this project,coliform bacteria have been detected in the study streams in previous years. There arepotential health risks associated with fecal contamination in drinking water, and localresidents/water users should take appropriate precautions to address this issue.

APPENDIX A

Water Quality Monitoring Sites - Location Map

APPENDIX B

2002 Lab Analysis Data

APPENDIX C

Precipitation and Stream Discharge Data

Appendix E - Environment Canada Climate Data (1948-2002)South BC Mountains - Regional Precipitation Departures From NormalRanked Driest to Wettest, 1948 - 2002

Summer Precipitation Fall PrecipitationRank Yr Dep. % Yr Dep. % Yr Dep. %

1 1975 -27.5 1967 -49.2 1952 -58.82 1956 -25.3 1973 -37.0 1976 -42.73 1965 -24.7 1979 -35.8 1987 -40.84 1973 -23.4 2002 -33.2 1979 -35.15 1952 -23.2 1970 -30.7 2001 -28.16 1949 -19.5 1958 -26.8 1993 -27.37 1958 -18.8 1985 -25.4 2002 -26.58 1970 -18.6 1974 -20.5 1957 -23.09 1992 -16.2 1961 -19.7 1956 -20.810 2001 -15.6 1951 -18.2 2000 -20.111 1963 -15.6 1998 -15.8 1974 -16.912 1979 -15.3 1960 -15.7 1948 -16.513 1982 -15 1949 -15.5 1972 -15.914 1985 -11.2 1950 -12.3 1953 -13.115 1983 -10 1956 -6.5 1981 -11.116 1957 -9.2 1965 -5.1 1983 -8.917 1951 -5.5 1955 -4.6 1970 -7.218 1971 -5 1994 -4.6 1949 -6.419 1954 -4 1984 -2.3 1989 -5.920 1999 -3 1971 -1.9 1991 -5.921 1962 -2.7 1992 -1.8 1975 -5.722 1953 1.2 1978 -1.5 1954 -4.523 1995 1.4 2000 -0.9 1960 -2.924 1994 2.3 1977 -0.7 1965 -1.225 1976 5.1 2001 0.4 1971 -1.126 1967 5.9 1952 0.5 1978 1.227 1989 6 1986 3.2 1999 1.328 1950 6.2 1987 3.7 1967 1.429 1987 6.6 1962 5.9 1977 2.330 1966 8.8 1969 6.2 1980 2.931 1991 9.2 1988 7.2 1997 4.032 1964 9.7 1966 9.5 1994 4.533 1972 10 1968 9.6 1982 4.634 1977 10.2 1975 9.6 1969 7.035 1986 10.5 1996 12.9 1962 8.436 1969 10.9 1997 15.3 1988 8.537 2000 12.7 1953 16.5 1963 9.338 1998 13.8 1972 16.8 1968 9.839 1978 14.7 1991 17.5 1950 10.740 1968 15.5 1959 17.9 1964 13.941 1955 15.6 1982 18.6 1951 14.442 1980 17.8 1989 18.8 1955 14.743 1961 18.8 1980 23.3 1966 16.444 1993 19.9 1963 25.1 1984 18.945 1948 23.3 1990 25.3 1995 20.846 1960 23.3 1957 25.8 1992 22.847 1974 23.7 1954 29.0 1961 23.348 1984 26.2 1981 30.4 1990 23.749 1981 26.6 1999 35.7 1986 26.050 1959 29.5 1964 37.4 1958 26.951 1988 36.5 1976 43.1 1973 27.652 1997 36.9 1995 45.4 1998 34.053 1990 38.1 1983 51.3 1985 37.154 2002 47.7 1948 64.7 1996 61.755 1996 51.9 1993 71.1 1959 66.1

Spring Precipitation

Mission Creek at East Kelowna (WSC #08NM116)Area (ha): 81100

Year Max Daily Discharge (m3/s) m3/s/ha Rank n aProbability of Exceedance

Recurrance Interval

1949 49.3 0.00061 27 52 0.4 51.0% 2.01950 52.1 0.00064 23 52 0.4 43.3% 2.31951 49.3 0.00061 27 52 0.4 51.0% 2.01952 50.7 0.00063 25 52 0.4 47.1% 2.11953 62.3 0.00077 11 52 0.4 20.3% 4.91954 36.2 0.00045 44 52 0.4 83.5% 1.21955 34 0.00042 49 52 0.4 93.1% 1.11956 38.5 0.00047 41 52 0.4 77.8% 1.31957 42.5 0.00052 37 52 0.4 70.1% 1.41958 34 0.00042 49 52 0.4 93.1% 1.11959 53.8 0.00066 19 52 0.4 35.6% 2.81960 49 0.00060 29 52 0.4 54.8% 1.81961 64.6 0.00080 9 52 0.4 16.5% 6.11962 Flow Data not Available1963 35.4 0.00044 46 52 0.4 87.4% 1.11964 71.4 0.00088 5 52 0.4 8.8% 11.31965 39.4 0.00049 39 52 0.4 73.9% 1.41966 Flow Data not Available1967 45.9 0.00057 32 52 0.4 60.5% 1.71968 50.1 0.00062 26 52 0.4 49.0% 2.01969 87.5 0.00108 1 52 0.4 1.1% 87.01970 34.8 0.00043 47 52 0.4 89.3% 1.11971 62.6 0.00077 10 52 0.4 18.4% 5.41972 81.8 0.00101 3 52 0.4 5.0% 20.11973 37.7 0.00046 43 52 0.4 81.6% 1.21974 66 0.00081 8 52 0.4 14.6% 6.91975 48.7 0.00060 30 52 0.4 56.7% 1.81976 71.1 0.00088 6 52 0.4 10.7% 9.31977 36 0.00044 45 52 0.4 85.4% 1.21978 44.5 0.00055 34 52 0.4 64.4% 1.61979 43 0.00053 36 52 0.4 68.2% 1.51980 46.2 0.00057 31 52 0.4 58.6% 1.71981 60.6 0.00075 12 52 0.4 22.2% 4.51982 54.5 0.00067 17 52 0.4 31.8% 3.11983 60.2 0.00074 13 52 0.4 24.1% 4.11984 52.4 0.00065 21 52 0.4 39.5% 2.51985 52.3 0.00064 22 52 0.4 41.4% 2.41986 72.5 0.00089 4 52 0.4 6.9% 14.51987 43.4 0.00054 35 52 0.4 66.3% 1.51988 37.9 0.00047 42 52 0.4 79.7% 1.31989 39 0.00048 40 52 0.4 75.9% 1.31990 69.9 0.00086 7 52 0.4 12.6% 7.91991 56.7 0.00070 16 52 0.4 29.9% 3.31992 29.8 0.00037 52 52 0.4 98.9% 1.01993 58 0.00072 15 52 0.4 28.0% 3.61994 39.7 0.00049 38 52 0.4 72.0% 1.41995 33.1 0.00041 51 52 0.4 96.9% 1.01996 53.9 0.00066 18 52 0.4 33.7% 3.01997 83.6 0.00103 2 52 0.4 3.1% 32.61998 44.7 0.00055 33 52 0.4 62.5% 1.61999 52 0.00064 24 52 0.4 45.2% 2.22000 52.5 0.00065 20 52 0.4 37.5% 2.72001 34.6 0.00043 48 52 0.4 91.2% 1.12002 59 0.00073 14 52 0.4 26.1% 3.8

Max 87.5Min 29.8Mean 51.1*Probability of exceedance based on Gringorten equation --- P.E.=Rank-a/n+1-(2a), Recurrance Interval =1/P.E.

Maximum Daily Discharges (m3/s) at Mission Creek near East Kelowna(WSC #08NM116)

0

10

20

30

40

50

60

70

80

90

100

1945 1955 1965 1975 1985 1995 2005

Year

Max

imum

Dai

ly D

isch

arge

(m3/

s)

87 Year Event 33 Year

Event

4 Year Event

Mean 51.1 m3/s

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