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Mark Creek Flume Flood Management CITY OF KIMBERLEY MARK CREEK FLUME HYDROLOGICAL & HYDRAULIC ASSESSMENT ISSUED FOR USE – January 31, 2012 FILE: 2011-015 LCI LACAS CONSULTANTS INC. CONSULTING ENGINEERS & HYDROLOGICAL SPECIALISTS, SINCE 1991 Suite 200, 1311 Howe Street, Vancouver, BC, Canada, V6Z 2P3 Telephone: 604.688.2535 Facsimile: 604.669.3688 Email: [email protected] CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 EXECUTIVE SUMMARY LaCas Consultants Inc. (LCI) was retained by Aqua-Tex Scientific Consulting Ltd. on behalf of the City of Kimberley to update the hydrology of Mark Creek and to assess the hydraulic capacity of the existing Mark Creek flume, located within the City of Kimberley, BC (Figure 1). The purpose of this report is to evaluate the existing flood risk to the City of Kimberley based on a 1 in 200 year recurrence interval instantaneous peak flood flowing through the existing Mark Creek flume. This initial report will lay the ground work for the following report by LCI, “Mark Creek Flume – Stream Rehabilitation Project”, in which multi- disciplinary criteria is integrated into the design of a new stream channel. This is not a design report for a new stream channel replacing the existing flume. The study area includes a 480 m long reach bracketing Mark Creek flume. The reach upstream of the flume appears to have been channelized and armoured with rock riprap. The flume itself is a rectangular concrete channel flowing through the city and re-enters a channelized open channel downstream in the vicinity of Jenning’s Street. The existing Mark Creek flume was constructed in the 1950’s as flood control solution to the devastating 1948 flood which caused extensive flood damage to the town of Kimberley. The 1948 flood avulsed and flowed down city streets creating channels and washing several buildings away. The US Army Corps of Engineers, River Analysis Model (v. 4.1.0) was used as the hydraulic model to determine the water surface profile for the 200-year flood in Mark Creek and the average channel velocities. The 200-year flood at the downstream end of the project is estimated to be 66 m3/s, which includes Kimberley Creek inflows. The hydraulic modeling results indicated that Mark Creek channel is steep enough to sustain supercritical flow throughout its length which results in relatively shallow water depths coupled with extreme average channel velocities. Within the flume the average channel velocities exceed 16 m/s which would be a risk to life for anyone in the channel during a flood event. Furthermore, the higher than normal flow velocities would leave very little warning to the public if a flood event approaches the City. The water surface profiles indicated that it would be desirable to reduce the flow inputs into the flume by a separate upstream diversion of Kimberley Creek directing water at the Kimberley Creek intake point through to Taylor’s Slough with adequate channelization downstream returning the flow into Mark Creek downstream of the flume. The diversion of Kimberley Creek is discussed in a separate report by LCI. LCI PAGE (i) CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 The hydraulic modeling also showed that with the exception of possible overbank flooding upstream of the entrance to the flume, the 200-year clear-water flood of 66 m3/s would be contained within the flume. However, the flow is expected to jump out of the channel upstream of the flume inundating properties and roads. Furthermore, when a debris flood is considered a minimum 1.5 m freeboard is recommended for the flume; which appears to be difficult to maintain through the length of the existing flume with the current flume geometry. The conclusion from a hydrological and hydraulic engineering perspective is that the flume in its current state is a danger to the public during a major flood event. It is recommended that the flume be replaced with a combination of wider channel reaches and drop structures to reduce the extreme velocity. It is recommended that the City erect signs along the existing flume warning the public of high velocity flow and flooding. Furthermore, the City should prepare emergency procedures to ensure the protection of the public and mitigate floodwater damage to properties during a flood event. LCI PAGE (ii) CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 TABLE OF CONTENTS Page EXECUTIVE SUMMARY i 1. INTRODUCTION 1 2. MARK CREEK HYDROLOGY 2 2.1 Hydrological Analysis 2.2 Peak Flow Estimates 3. MARK CREEK FLUME HYDRAULIC MODELING 5 3.1 Hydraulic Modeling Parameters 3.2 Hydraulic Modeling Results 4. CONCLUSIONS AND RECOMMENDATIONS 6 5. CLOSURE AND REPORT LIMITATIONS 7 LIST OF FIGURES Figure 1 - Location Plan Figure 2 - Mark Creek Flume, Hydrological & Hydraulic Assessment Plan View Figure 3 - Mark Creek Flume, Hydrological & Hydraulic Assessment 200-Year Flood Profile APPENDIX Table 3 - Mark Creek Flume Modeling Results for 200-Year Flood (66 m3/s) LCI PAGE (iii) CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 1. INTRODUCTION LaCas Consultants Inc. (LCI) was retained by Aqua-Tex Scientific Consulting Ltd. on behalf of the City of Kimberley to update the hydrology of Mark Creek and to assess the hydraulic capacity of the existing Mark Creek flume located within the City of Kimberley, BC (Figure 1). The purpose of this report is to evaluate the existing flood risk to the City of Kimberley based on a 1 in 200 year recurrence interval instantaneous peak flood flowing through the existing Mark Creek flume. The Mark Creek flume was constructed in the 1950’s as flood control solution to the devastating 1948 flood which caused extensive flood damage to the town of Kimberley. The 1948 flood avulsed and flowed down city streets creating channels and washing several buildings away. The flume is 380 m long, about 2 m deep and 6 m wide at an average slope of 8 percent. There are several crossings of the flume including vehicular bridges, a pedestrian bridge, waterlines, gas lines and the Sullivan mine acid rock drainage treatment waterline (Figure 2). The US Army Corps of Engineers, River Analysis Model (v. 4.1.0) was used as the hydraulic model to determine the water surface profile for the 200-year flood in Mark Creek and the average channel velocities. In addition, the report addresses the possible impact of debris floods which are characterized by a combination of bedload movement, suspended sediment load, and floating organic debris. The movement is part of the flood process in which the flow behaves as a water flood, rather than a hillslope process such as a debris flow or / channelized landslide. Previous pertinent reports1,2, photographs and historical memoranda were reviewed. 1 Klohn-Crippen, April 1999, City of Kimberley, Mark Creek Flood Assessment, Project No. 98-04-19. 2 BC Environment, Water Management Branch, June 1995, Mark Creek Hydrology Data Summary and Analysis. __________________________________________________________________________________________________________________ LCI PAGE 1 of 9 CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 2. MARK CREEK HYDROLOGY 2.1 Hydrological Analysis Located in Kootenay Valley, Mark Creek flows southward to its confluence with the St. Mary River just south of the City of Kimberley. The drainage area of Mark Creek at the end of the concrete flume in the City of Kimberley is approximately 135 km2. The median basin elevation of the watershed is approximately 1780 m. It should be noted that a concrete dam and reservoir are located within the Mark Creek watershed upstream of the City of Kimberley. Kimberley Creek is one of the major tributaries of Mark Creek, and it has a drainage area of approximately 25 km2 at its mouth. The median basin elevation of the Kimberley Creek watershed is approximately 1300 m. There are a number of hydrometric stations on Mark Creek, but most of them are designated as ‘regulated’. There is a hydrometric station on Mark Creek (08NG085) with a relatively long period of record, measuring natural flows, and it was operated by Water Survey of Canada (WSC) from 1989 to 1998 and has been operated by the City of Kimberley since 1999. Historical hydrometric data from this station (Mark Creek Above Diversions) was obtained both from the Water Survey of Canada and from available Mark Creek resource inventory reports. The Water Survey of Canada has one ‘natural’ hydrometric station on Kimberley Creek near Kimberley (08NG057), but this station was only operated from 1968 to 1973 and has limited peak flow data. Other useful regional hydrometric stations operated by the WSC include the Mather Creek below Houle Creek (08NG076), St. Mary River below Morris Creek (08NG077), and St. Mary River near Marysville (08NG046). The hydrometric stations used in this study are listed in Table 1. Table 1: Regional Hydrometric Stations Station ID Station Name Drainage Period of Years of Peak Flow Data Status Area (km2) Record 08NG046 ST. MARY RIVER 1480 1945 - 1995 48 Daily, 20 Instant. Active NEAR MARYSVILLE 08NG076 MATHER CREEK 135 1972 - 2011 38 Daily, 38 Instant. Inactive BELOW HOULE CREEK 08NG077 ST. MARY RIVER 208 1973 - 2011 38 Daily, 35 Instant. Inactive BELOW MORRIS CREEK 08NG085 MARK CREEK 102 1989 - 2010 24 Daily, 25 Instant. Inactive ABOVE DIVERSIONS __________________________________________________________________________________________________________________ LCI PAGE 2 of 9 CITY OF KIMBERLEY MARK CREEK FLUME Hydrological & Hydraulic Assessment - Issued for Use January 31, 2012 By analyzing available peak flow data at the Mark Creek Above Diversions station, it was determined that peak flows in the study area usually occur in May or June, as a result of snowmelt.
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