Investigating the Dynamic Hydrology of Garibaldi Lake

By: Tenea Dillman Host Faculty Member: Steve Quane Abstract: Garibaldi Lake is located north of Squamish, BC at an elevation of 1470 meters, roughly 1100 meters above the Cheakamus valley and highway 99. This alpine lake is held in by an archetypically unstable ice-contact volcanic deposit, The Barrier. Springing from the base of The Barrier is Rubble Creek, which is assumed to be the primary outflow from the lake (besides a seasonal overflow stream). Very little is known about the dynamics of this hydrological system, hence I designed a monitoring system to quantify its behaviour. The monitoring system comprises: the volumetric discharge of outflows, volumetric discharge of inflows, and the subsequently changing volume of Garibaldi Lake. Questions explored throughout this paper include: How do seasonal glacial and snowpack melt input affect the water level of the lake and the outflow at both Rubble Creek and the overflow creek? Does Rubble Creek respond to changes in lake behaviour (thus acting as a participant in the hydrodynamic system)? And, is there a correlation between lake level and outflow levels? Using this method, I can begin to monitor intermediate (seasonal) to long term (yearly) behavior of the Garibaldi Lake-Barrier- Rubble Creek hydrodynamic system. Preliminary results show correlation between lake water level behaviour and overflow creek discharge. It is probable that the lake water level is directly responding to glacial and snowpack melt. However, it is yet unclear the degree to which the flow in Rubble Creek dependent on the rest of the hydrodynamic system.

Introduction: Garibaldi Lake, elevation 1470 m, is located about 25 km north of Squamish, BC (1100 m above highway 99) and is a popular hiking destination, renowned for its beauty and unique geological origin. Yet, many questions remain regarding hydrological processes controlling its behavior. For example, how do seasonal glacial and snowpack melt input affect the water level of the lake and the outflow at both Rubble Creek and the overflow creek? Does Rubble Creek respond to changes in lake behaviour (thus acting as a participant in the hydrodynamic system)? And, is there a correlation between lake level and outflow levels? To investigate this I designed a monitoring program for the Garibaldi Lake/Rubble Creek hydrological system. The objective of this monitoring system is to answer the above questions. This site is both unique and very interesting due to the lake’s formation through volcanic and glacial activity. During the Pleistocene epoch the land around present day Garibaldi Park was covered by the Cordilleran Ice Sheet (Clague, J., Ward, B., 2012). About 11,000 years ago the combination of both valley and mountain glacier retreat resulted in an ice free window between 1000m and 1500m elevation (Mathews, W.H., 1952). An eruption from Clinker Peak extruded a lava flow which, while flowing down gradient towards the Cheakamus valley, collided with the 1 km thick remnant valley glacier. The lava ponded and solidified in a wall (about 300 m tall) against the glacier, forming the geological phenomenon termed The Barrier. The Barrier acts as a dam in the valley, allowing run off water to collect behind it and form Garibaldi Lake (Mathews, W.H., 1956). The waters comprising Garibaldi Lake are a combination of glacial melt water from Sphinx Glacier, Sentinel Glacier, and small mountain streams. These small mountain run offs arise mostly from precipitation and snow melt. Lake inflow and outflow locations are outlined in Figure 1. Rubble Creek, located to the west of Garibaldi Lake is the main outflow of this alpine lake hydrological system, however there is also a seasonal overflow creek on the western bank of Garibaldi Lake that flows into Lesser Garibaldi and Barrier lakes. Rubble Creek springs from the base of The Barrier at an elevation of about 965 m and flows directly into the Cheakamus River (under highway 99). It has an average flow rate between 2 and 4 m3/s (Quane, S.L. and Stockwell, J. 2014). Garibaldi Lake’s overflow creek is referred to as Rubble Creek in both Garibaldi Provincial Park, Natural History Themes (BC ministry of Environment, Lands and Parks, 1992) and Physical Limnology and Sedimentation in a Glacial Lake (Mathews, W.H., 1956), however, for clarity, I will refer to it as “the overflow creek” as it does not appear to connect to the springs at the base of The Barrier except for during major precipitation events. In this project, I designed a monitoring program for the Garibaldi Lake hydrological system. I created a monitoring method for each component of the model, including the discharge of outflows, discharge of inflows, and the volume of Garibaldi Lake. Using the system detailed below, I can now, for the first time, monitor intermediate (seasonal) to long term (yearly) behavior of the Garibaldi Lake-Barrier-Rubble Creek hydrologic system. Methods: The main goal of this study is to quantify and monitor the inflow and the outflow from Garibaldi Lake as well as the resulting change in lake level. Following, I detail the methods by which I have assessed each parameter. Discharge of Inflows: As seen in Figure 1, Garibaldi Lake has sixteen inflow locations. Due to the steep topography surrounding Garibaldi Lake, it is only possible to measure discharge at two of these locations, Sphinx and Sentinel creeks (represented by IN10D and IN7D, respectively, in Figure 1) on the eastern end of the lake. At those locations, I was able to directly measure volumetric flow rate through the method of salt dilution gauging (Moore R.D., 2003) on June 26th, 2015 and July 21st, 2015. In order to best approximate the total inflow into Garibaldi Lake, I had to approximate flow in the remaining inputs. In order to assess the importance of a certain inflow source, I developed a rating system. I numbered and labeled each inflow according to this system: A- No observable flow, but evidence for seasonal flow (evidence defined as a permanent fluvial channel extending past local snow melt). B- Flowing stream. Estimated rate less than 0.5 m3/s. C- Flowing stream. Estimated rate more than 0.5 m3/s, but less than 1 m3/s. D- Flowing stream. Estimated rate more than 1 m3/s. On June 26th, 2015 and July 21st, 2015 using a 14’ aluminum boat with outboard motor (housed at the lake by BC Parks) I circumnavigated the lake. In this way, I identified and located lake inflows. For each inflow found, I took GPS locations as close to shore as possible, assigned a rating, estimated the flow rate, and photographed the locations. I made estimates visually from the boat, at up to 10 m distance from shore. They are accurate up to 1 sigma. Two exceptions to this method are the Sphinx and Sentinel creeks for which the discharge was measured via salt dilution.

Figure 1: Aerial view of Garibaldi Lake and surrounding geological features (49°55’N, 123°02’W) showing input and output locations for the Garibaldi Lake system, obtained from Google Earth (2015). Top of image is North. Each inflow is identified by a blue pin, a number and an importance rating according to the rating system defined in the text. Both outflows are identified by a yellow pin, a number and their name. Discharge of Outflows: Despite the large number of inflow locations, Garibaldi Lake has only two discernable outflows, the overflow creek and Rubble Creek (represented by OUT1 Seasonal Overflow and OUT2 Barrier Spring, respectively in Figure 1). Rubble Creek: As mentioned previously, Rubble Creek springs from the base of The Barrier (Figure 2). It does this in several places, before converging at a point approximately one hundred meters down the valley. The creek is fast moving and turbulent and the creek bed is comprised mostly of boulder cascade morphology.

Figure 2: Bird’s eye view of Rubble Creek (looking east). In the background The Barrier exists as a rock face with a large amount of scree around the base. At the bottom of this scree, Rubble Creek emerges and makes its way down the valley. Overflow Creek: Garibaldi Lake’s overflow creek exists seasonally, when snow pack melting and glacial melting occurs (normally May through early October). While not as turbulent as Rubble Creek, during high flow periods the current is strong enough to carry large amounts of debris, evidenced by the several log jams that exist between Garibaldi Lake and Lesser Garibaldi Lake. A foot bridge is installed to allow access to the lake campground on the other side (Figure 3).

Figure 3: The overflow creek looking out to Garibaldi Lake (facing approximately west). In the foreground a foot bridge crosses the dry creek bed that will eventually carry overflow water into Lesser Garibaldi Lake. Support beams for this bridge are attached to the rock face and cement footing as seen in Figure 5. In the background Garibaldi Lake remains frozen (photo taken in early May). In order to continuously measure the discharge of Rubble Creek and the overflow creek I employed a Solinst Levelogger Junior Edge (a pressure sensor data logger) and a Solinst Levelogger Edge Barologger (an atmospheric pressure sensor data logger) to each area. Data from the Junior Edge logger is compensated with the Barologger in order to obtain water pressure only. Measurements are made once per hour, on the hour. This provided a continuous data set of stream stage (also referred to as water level). The Rubble Creek level logger and barologger were set up as close as possible to the confluence point of its springs in order to measure only the spring water, which is hypothesized to be coming from Garibaldi Lake, and avoid as much precipitation runoff as possible. The over flow creek level logger and barologger were installed as close to the lake as possible so as to measure only lake flow and avoid precipitation runoff from the surrounding topography. Figure 4 shows the locations for all three logger installations.

Figure 4: Aerial view of Garibaldi Lake and surrounding geological features (49°55’N, 123°02’W) showing locations for data logger installation, obtained from Google Earth (2015). Image is north facing. In order to protect the level loggers from debris and other hazards it is hung by sheathed metal cord inside a six foot ABS pipe (Figure 5). This pipe is then strapped to a permanent feature using aluminum plumbing tape. The overflow logger is attached to the cement footing below the bridge, the Rubble Creek logger is attached to a stable boulder and the lake logger is attached to the BC Parks dock.

Figure 5: Solinst Levelogger Junior Edge set up at the overflow creek. Seen in this photo are wooden support beams for the bridge crossing. The ABS pipe is attached to a cement footing at the base of the bridge. From here I correlate discharge with stage by graphing a stage-discharge curve. To do this I take discharge measurements at various stages through the process of salt dilution gaging (Moore R.C., 2003) and graph them against the stage. By covering a wide variety of water levels I am able to estimate discharge for any point in time via interpolation of this graph (Figure 6). Assuming the cross sectional area of the stream does not change drastically, the discharge of a stream correlates strongly with stream stage. However, because this discharge curve can change, either due to storm events or gradual erosion of the stream bed, it must be updated constantly by making regular measurements of both stage and discharge and re-graphing. The same process will be used for Rubble Creek. Discharge curve: Stage VS Discharge for the Overflow Creek 1.200

1.000

0.800

0.600 Stage 0.400

0.200

0.000 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 Discharge

Figure 6: Stage Discharge Curve for the overflow creek. Discharge measurements taken via the salt dilution method are shown as solid dots, while the lines connecting represent interpolated data. Lake Volume: Similar to the outflow measurement stations, I used a Solinst Levelogger Junior Edge to record the fluctuations in lake water level. It was installed in the same design, within an ABS pipe and attached to the dock. Measurements are also made once per hour, on the hour. The same barometer is used to compensate for atmospheric pressure as is used for the overflow creek because they are on the same elevation and are in similar vicinity. As a method of confirming the water level changes given by the level loggers, I use a staff gauge to obtain a separate measurements. A staff gauge is essentially a large ruler with which I read off a water level measurement compared to a fixed point. This can only be done in person, which is why I use it only to confirm the measurements obtained by the level logger. At the lake I measure water level compared to the dock, and at the overflow creek I measure the water level compared to the cement footing. Preliminary Results: Lake Outflow: Data collected at the Overflow Creek location (Figure 7) shows that Garibaldi Lake began to overflow on May 22nd, 2015 (about 750 h) and creek stage has generally increased since then. Initially, water level rose quite steadily and rapidly. However, around late June (approximately 1600 h) the water level dropped slightly before rising again. Since July 9th, 2015 (approximately 2100 h) water level has again dropped slightly. Overflow Creek Water Level Over Time 1.2

1

0.8

0.6

Stage (m) Stage 0.4

0.2

0 0 500 1000 1500 2000 2500 Time Points (h) Figure 7: Overflow Creek stage. Data set begins on May 7th, 2015 at 17:00 hours and ends on July 21st, 2015 at 13:00 hours. Points correspond with the left hand vertical axis and represent the overflow creek stage. Measurements correspond with time, in time points (one per hour), on the horizontal axis. Water level remained at 0 m until May 22nd 2015 then began a steady increase. The maximum level achieved between May 7th 2015 and July 21st, 2015 is approximately 1.1 m, occurring on July 6th, 2015 around mid-day (approximately 2100 h). Garibaldi Lake water level has also been on a downward trend since July 7th, 2015 (Figure 8). Prior to July 7th (approximately 50 h), water level had been rising. Around July 18th (approximately 210 h), water level began to rise again, but only slightly before beginning to fall again around July 21st (approximately 280 h).

Garibaldi Lake Water Level 1.5

1.48

1.46

1.44

1.42 Water Level (m) Level Water 1.4 0 50 100 150 200 250 300 Time Points (h)

Figure 8: Garibaldi Lake water level. Data set begins on July 9th, 2015 at 15:00 hours and end on July 21st, 2015 at 15:00 hours. Points correspond with the left hand vertical axis and represent lake level. Measurements correspond with time, in time points (one per hour), on the horizontal axis. Maximum level achieved was approximately 1.5 m, occurring on July 11th, 2015. During the period of July 9th, 2015 to July 21st, 2015, the level from Garibaldi Lake and the overflow creek show a similar pattern (Figure 9). Both water levels are rising until around July 7th (approximately 50 h), when they began to fall until July 18th (approximately 210 h) and rise slightly until July 21st (approximately 280 h) when they both began to fall again.

Water Levels of Garibaldi Lake and Overflow Creek Over Time 1.11 1.49 1.1 1.48 1.09 1.47 1.08 1.46 1.07 1.45 1.06 1.44 1.05 1.43

1.04 1.42 Garibaldi Lake (m) Lake Garibaldi Overflow Creek (m) Creek Overflow 1.03 1.41 1.02 1.4 0 50 100 150 200 250 300 Time Points (h)

Figure 9: Water levels of Garibaldi Lake and Overflow Creek over time. Both data sets begin on July 9th, 2015 at 15:00 hours and end on July 21st, at 15:00 hours. The orange points correspond with the left hand vertical axis and represent the overflow creek stage. The blue points correspond with the right hand vertical axis and represent lake level. Measurements correspond with time, in time points (one per hour), on the horizontal axis. The general trend for water level in Rubble Creek is a steady, slow increase (Figure 10). Maximum water level achieved was 0.357 m on July 15th, 2015. Shortly after this the water level drops quickly, then recommences its gradual increase at a similar rate. It is uncertain whether the cause of this sharp drop of 3.5 cm is natural or an artifact in the data collection method. Measurements began at Rubble Creek at a water level of 0.321 m (July 9th, 2015 at 15:00 hours) and ended at a level of 0.347 m (July 21st, 2015 at 10:00 hours) resulting in a net increase of 0.026 m (or 2.6 cm) over the course of this time. Rubble Creek Stage 0.38 0.36 0.34 0.32 0.3 0.28

Stage (m) Stage 0.26 0.24 0.22 0.2 0 50 100 150 200 250 300 350 400 450 Time Points (h)

Figure 10: Rubble Creek stage. Data set begins on July 2nd, 2015 at 17:00 hours and ends on July 21st, 2015 at 10:00 hours. Points correspond with the left hand vertical axis and represent Rubble Creek stage. Measurements correspond with time, in time points (one per hour), on the horizontal axis. Maximum level achieved was approximately 0.357 m, occurring on July 15th, 2015. Rubble Creek and Garibaldi Lake water levels do not appear to be directly and simply correlated (Figure 11). Over the same time span the lake level appears to be falling, opposed to Rubble Creek which appears to be rising. I hope that the nature of this relationship can be elucidated through future continuous monitoring.

Rubble Creek Stage Compared to Lake Level Over Time 1.49 0.36 1.48 0.35 1.47 1.46 0.34 1.45 0.33 1.44

1.43 0.32 Lake Level (m) Level Lake 1.42 0.31 1.41 (m) Stage Creek Rubble 1.4 0.3 0 50 100 150 200 250 300 Time Points (h)

Figure 11: Rubble Creek stage compared to lake level fluctuations. Both data sets begin on July 9th, 2015 at 15:00 hours and end on July 21st, 2015 at 10:00 hours. The orange points correspond with the left hand vertical axis and represent lake level. The blue points correspond with the right hand vertical axis and represents Rubble Creek stage. Measurements correspond with time, in time points (one per hour), on the horizontal axis. Lake Inflow: Lake inflow locations, identified during the June 26th, 2015 circumnavigation of Garibaldi Lake, are shown in Figure 1. There are sixteen separate inflows to Garibaldi Lake and two outflows. One of these outflows, “OUT1 seasonal overflow”, occurs only seasonally during the periods of high glacial melting (normally May through early October). Only two of the inflows contribute more than 1 m3/s volumetric flow: Sphinx creek and Sentinel creek, both of which originate at their respective glaciers (Figure 1).

Table 1: Garibaldi Lake inflows, estimated June 26th 2015 Latitude Longitude Rating Estimation Name (N) (W) (m3/s) IN1B 49.92839 -123.039 B 0.100 IN2B 49.91201 -123.017 B 0.005 IN3B 49.91146 -123.016 B 0.020 IN4B 49.90747 -123.012 B 0.500 IN5B 49.90725 -123.011 B 0.500 IN6A 49.90478 -123.006 A 0.000 IN7D (Sentinel ) 49.90583 -123.004 D 0.300 IN8B 49.91873 -122.998 B 0.050 IN9B 49.91957 -122.997 B 0.500 IN10D (Sphinx) 49.92853 -122.994 D 2.280 IN11B 49.93804 -123.002 B 0.500 IN12C 49.94342 -123.011 C 0.700 IN13A 49.94516 -123.018 A 0.000 IN14A 49.94681 -123.027 A 0.000 IN15B 49.95079 -123.041 B 0.300 IN16B 49.94851 -123.047 B 0.020 Total 5.775 For each inflow the coordinates, rating and estimation is given. The estimated cumulative inflow for Garibaldi Lake totalled 5.775 m3/s on June 26th, 2015. Sphinx and Sentinel creeks account for 2.58 m3/s of this total.

Table 2: Garibaldi Lake inflows, estimated on July 21st 2015 Latitude Longitude Rating Estimation Name (N) (W) (m3/s) IN1B 49.92839 -123.039 B 0.100 IN2B 49.91201 -123.017 B 0.050 IN3B 49.91146 -123.016 B 0.010 IN4B 49.90747 -123.012 B 0.040 IN5B 49.90725 -123.011 B 0.040 IN6A 49.90478 -123.006 A 0.000 IN7D (Sentinel ) 49.90583 -123.004 D 1.960 IN8B 49.91873 -122.998 B 0.010 IN9B 49.91957 -122.997 B 0.040 IN10D (Sphinx) 49.92853 -122.994 D 0.550 IN11B 49.93804 -123.002 B 0.200 IN12C 49.94342 -123.011 C 0.300 IN13A 49.94516 -123.018 A 0.015 IN14A 49.94681 -123.027 A 0.000 IN15B 49.95079 -123.041 B 0.030 IN16B 49.94851 -123.047 B 0.005 Total 3.350 For each inflow the coordinates, rating and estimation is given. The estimated cumulative inflow for Garibaldi Lake totalled 3.350 m3/s on July 23rd, 2015. Sphinx and Sentinel creeks account for 2.510 m3/s of this total. Compared to estimations made on June 26th, 2015 (Table 1), inflow rate had decreased by July 23rd, 2015 (Table 2). Total flow rate decreased by 2.425 m3/s. Sentinel Creek increased by 0.250 m3/s, however Sphinx Creek decreased by 0.320 m3/s and the cumulative inflow from the smaller streams decreased by 2.355 m3/s. For descriptions and photographs of each inflow see Appendix A. Estimates for several inflow creeks outlined above were made previously in 1982 and published in Garibaldi Lake Natural History Themes, BC Ministry of the Environment, Lands and Parks (Revised June 1992). For a table summarizing these values see Appendix B.

Discussion: Over the course of the near two week period exhibited in Figure 9, water levels of both Garibaldi Lake and the overflow creek fluctuated in correspondence. This correlation suggests that the behaviour of these features are connected; as lake inflow increases, raising water level, the outflow from the lake will increase mediating the effects. Likewise, as the inflows decrease, lake level will decrease and less water will overflow. If the overflow creek is the only outflow source for Garibaldi Lake then the water level of the lake would not drop below creek bed height (barring any evaporation). However, as it is assumed that Rubble Creek is an additional outflow, the lake level will likely drop significantly further during the low-inflow winter months. During the hour between July 15th, 2015, 23:00 hours, and July 16th, 2015, 0:00 hours, Rubble Creek water level dropped 3.5 cm (Figure 11). This seems unusual, however it is possible. Conceivably, this was a glitch when the total pressure was compensated with the atmospheric pressure from the barometer. Despite this one anomaly, Rubble Creek stage experiences a generally increasing trend between July 9th, 2015 and July 21st, 2015. As seen in Figure 11, Garibaldi Lake is not correlating with this behaviour. Over the same time span the lake appears to follow a downward trend, opposed to upward. This does not necessarily mean that Rubble Creek is not acting as a participating part of the hydrodynamic system, however, as due to the large distance covered via ground water the reactions could merely be delayed. General patterns in water level behaviour will become clearer once data is collected over a longer time period. Over the course of a year I am expecting Rubble Creek water level to form a generally increasing trend in the late summer when lake level is highest and a generally decreasing trend in the winter when the lake level is lowest, due to the changes in hydraulic head. According to our estimations (Table 1 and Table 2), the inflow to Garibaldi Lake is decreasing. If the amount of outflow over exceeds the inflows, the lake level will drop and the overflow creek will slow and/or stop all together. This correlates with the general trends experienced by the water level in the lake; between June 26th, 2015 and July 21st, 2015, inflow is decreasing and, as of July 11th, 2015 (Figure 8) the water level of the lake has been decreasing as well. One possible hypothesis is that the rate of inflow followed a similar pattern to that of the lake water level. This would mean that the inflow rate was rising when the first measurements and estimations took place on June 25th, 2015, but then began decreasing sometime between then and July 21st, 2015 (possibly sometime around July 11th, 2015) causing the decrease in lake water level. At this time this is merely speculation however, and general trends will become clearer once data is collected over a longer time period. Using data collected throughout the next year, a model will be created to compare the transfer of water throughout the system. From here we can extrapolate where and how the water is traveling, whether or not Rubble Creek responds to lake behaviour, whether or not the measureable inflows are equivalent to measureable outflows, and gain a more comprehensive understanding of the dynamics within this hydrological system.

Citations BC ministry of Environment, Lands and Parks (1992). Garibaldi Provincial Park, Natural History Themes. Buchanan, T.J., and Somers, W.P., (1969). Discharge measurements at gaging stations: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap A8, 65 p Clague, J., Ward, B., (2012). Chapter 44 - Pleistocene Glaciation of British Columbia, In: Jürgen Ehlers, Philip L. Gibbard and Philip D. Hughes, Editor(s), Quaternary Glaciations - Extent and Chronology: A Closer Look. Developments in Quaternary Sciences, Elsevier, 2011, Volume 15, Pages 563-573. Eamus, D., (2014). Groundwater – Catchment water balance, Climate and Groundwater. In Encyclopedia of Life Support Systems (EOLSS). Developed under the Auspices of the UNESCO, Eolss Publishers, Paris, France, [http://www.eolss.net]. Mathews, W.H., (1956), Physical limnology and sedimentation in a glacial lake: Bulletin of the Geological Society of America, Vol. 67, pgs. 537-552. Mathews, W.H., (1952), Ice-dammed lavas from Clinker Mountain, southwestern British Columbia: American Journal of Science, Vol. 250, pgs. 553-565. Moore R.D. (2003). Introduction to Salt Dilution Gauging for Streamflow Measurement: Part 1. Streamline Watershed Management Bulletin. Vol.7/No. 4 (Winter). Moore R.D. (2004). Introduction to Salt Dilution Gauging for Streamflow Measurement: Part 2. Streamline Watershed Management Bulletin Vol. 8/No. 1. (Fall). Moore R.D. (2005). Introduction to Salt Dilution Gauging for Streamflow Measurement: Part 3. Streamline Watershed Management Bulletin Vol. 8/No. 2. (Spring). Minnesota Department of Resources, (2007). Measuring Lake Levels. Retrieved from: http://files.dnr.state.mn.us/waters/surfacewater_section/lake_hydro/lake_level_gaging.pdf Province of British Columbia, (2015, January). BC Geographical Names. Retrieved From: http://apps.gov.bc.ca/pub/bcgnws/names/9718.html Quane, S.L. and Stockwell, J. (2014). Fire and Ice: Revealing Potential Hazards at Garibaldi Lake, British Columbia. Submitted to National Geographic Waitt Grant Program United States Geological Survey, (2014, March). How Streamflow is Measured. Retrieved from: http://water.usgs.gov/edu/streamflow2.html

Input 1: B. Spring emanating from forested hill formed from the foot of a lava flow.

Input 2: B. Table Bay. Shallow stream emanating from a moderately flat meadow. Suspected drainage valley for snow melt from the Table area.

Input 3: B. Also located in Table Bay. Likely a divergence of the previous stream in the Table area. Slightly smaller than relative stream.

Input 4: B. Obvious spring emanating at the contact point between oxidized and non-oxidized rocks (possibly contact point between lava flow and bedrock) in the upper table area.

Input 5: B. Obvious spring emanating at the contact point between oxidized and non-oxidized rocks (possibly contact point between lava flow and bedrock) in the upper table area.

Input 6: A. Wide fluvial channel stemming from upper table area.

Input 7: D. Sentinel Creek. Slow, shallow, meandering flow. Extensive braiding. Pools in several places.

Input 8: B. Thin, emanating from above mountains.

Input 9: B. Somewhat steep. Appears to originate in the mountains directly above, likely an ice field.

Input 10: D. Sphinx Creek. Wide, moderately paced creek. Creek passes through gap in large terminal moraine. Melt water accumulates in two lakes formed within the valley which then overflow into Garibaldi Lake.

Input 11: B. East of Gentian Peak. Steep, fast moving.

Input 12: B. East of Panorama Ridge. Very steep ravine, fast moving water, levels out close to lake.

Input 13: A. Insignificant stream discharge (~0.001 m^3/s). Large sediment deposit.

Input 14: A. Face of Panorama Ridge. Appears to be significant seasonal flow from local snow melt.

Input 15: B. Driftwood bay, Mimulus Creek. West of Panorama Ridge. Shallow, wide and slow moving.

Input 16: B. Closest to overflow creek. Shallow, wide and slow moving.

Appendix B: Estimates for major tributaries were given previously in Garibaldi Lake Natural History Themes, BC Ministry of the Environment, Lands and Parks (Revised June 1992).

Table 3: Major tributaries as outlined by Garibaldi Lake Natural History Themes Referred to in Referred Latitude (N) Longitude (W) Rating My estimate Their Natural to in my on July 21st estimate on History paper 2015 September Themes 13th 1982 Creek D IN2 49.91201 -123.017 B 0.050 0.11 Sentinel IN7 49.90583 -123.004 D 1.960 none Creek C IN9 49.91957 -122.997 B 0.040 none Sphinx IN10 49.92853 -122.994 D 0.550 1.43 Creek A IN11 49.93804 -123.002 B 0.200 none Creek B IN12 49.94342 -123.011 C 0.300 0.07/0.28 Mimulus Creek IN15 49.95079 -123.041 B 0.030 0.04