In this exercise, you will use the BC Water Tool to examine the overall geography of the watershed.

Step 1: Open the BC Water Tool website, and navigate to the Water Portal for the South and Coast Area (link near the top of the home page). You may have to accept a data license agreement.

Step 2: Zoom the map into the area of Vancouver, and to the Fraser Valley located to the east, and locate the sub-area outlined in Figure 20.1.

Step 3: Take 15 minutes and explore the Nicomekl River watershed using the BC Water Tool. You may wish to alternate your map view between the default line map view, and the satellite view. You can click on the i information icon to activate the map legend display. You may find that the top book icon (watershed reporting) does not work in this area.

Step 4: (Optional) If you are familiar with Google Earth (Web), you may also wish to explore the watershed using this program.

Step 5: Locate the Nicomekl River at the point where it flows east to west to the ocean at the hydrograph station to the left of Figure 20.1 (49.06917N or 49 04’ 09”N; 122.82500W or 122 49’ 30”W). Starting from this point, trace the river to the east where it passes through the City of Langley to the hydrograph station to the right of Figure 18.1 (49.10417N or 49 06’ 15” N; 122.6603W or or 122 39’ 37” W). Further to the east, the river may become difficult to trace.

Step 6: Examine some of the major tributaries of the Nicomekl as well. The Nicomekl has two side creeks that branch off to the south of the river – Anderson Creek just west of Langley, and another the branches off southeast of Langley.

Once you have taken some time to explore the watershed, use the BC Water Tool answer the following questions in 3-5 sentences each:

1. Using the Default map style and the Satellite map style, describe the land use within the watershed and estimate the approximate proportions (%) of the land within the Nicomekl watershed that are covered by farmland, urban land, and natural land.
2. Examine the character of the side creeks from the Nicomekl River on the south side of the river in the area of Highway 15 (from 168th to 164th St) in the Default map style, and compare to the Satellite map style. Describe the dominant land use and how it impacts the drainage pattern.
3. Examine the area of Langley city center (approx. 49.104, -122.657; the intersection of Glover Road or 203rd Street and the Fraser Highway). The urban area is bounded on the north by the Langley Bypass of Highway 10, on the south by the Nicomekl. On the west by 192nd Street and on the east by 208th Street and the Langley Bypass. There appear to be creeks branching off the Nicomekl river to the south and east. Describe how the channel patterns on the north side of the main Nicomekl channel differ compared to the south. Viewing both Default map style and Satellite map style, explain why.

In this exercise, we will visit a series of data sources using the BC Water Tool to visually examine graphs of climate and precipitation, stream discharge in the Nicomekl, and groundwater levels. You will note important features of the annual changes in each graph, then compare those to monthly average data prepared for you.

You will also download raw data in spreadsheet form. You will use this data in EX3. In each case, save the gathered data to a folder in a known location. If you find that you are unable to complete this step, contact your instructor, who will have a set of data downloaded that you can use.

Precipitation and Climate Data

Step 1: Click on the Cloud icon on the left of the screen to show climate stations. Click on the information icon (i) to see the legend for active and historical stations.

Step 2: Zoom out until you locate the closest active climate station. It is located south of the watershed close to the United States border in White Rock BC.

Step 3: Click on the station on the map and information will load on the right of the screen for White Rock station 1108910. Click DOWNLOAD DATA (large button also on the right of the screen) to download the data from this station. Save the file using the name suggested (station-data-12418.csv) to a folder you can find.

Step 4: On the bottom right of the screen, you will see panels indicating graphs for Temperature, Precipitation, and Snow on Ground. Depending on the size of your screen, you may need to scroll down to see these.

Step 5: Click on the panel for Precipitation. You should now see a graphic displaying precipitation such as the one shown in Figure 20.2. The graphic has the following features:

• Precipitation amount is plotted on the y-axis and date is plotted on the x-axis.
• The black horizontal line in each month indicates the median value in that month.
• Dark shading indicates the more common historical ranges of data in that month of the year.
• Light grey shading indicates the more extreme variations in historical data.
• Blue graphs show the cumulative amount of precipitation for each month in the current year.

Visually trace the black line across the figure. Write down which two months have the highest precipitation and which two months have the lowest precipitation.

Step 6: To exit this screen, click on the X located in the top right of the screen.

Hydrograph Data

Step 1: Click on the upwards trending graph icon to activate the display of the locations of hydrographic stations.

Step 2: Locate the active hydrograph station located near the center of Langley (Nicomekl River At 203 Street, Langley, 08MH155, 49 06’ 15” N, 122 39’ 37” W).

Step 3: On the right of the screen, click DOWNLOAD DATA and save the file (station-data-4268.csv) to your folder.

Step 4: On the right of the screen, click on 7 Day Flow. You will see a graph similar to Figure 20.3. The stream discharge is plotted on the y-axis in m³/s. The date is plotted on the x-axis. Statistical features are as per Figure 20.2. As you move the cursor across the screen, the values of the median value of discharge on that day, and the range over time, will be displayed. The orange (may appear yellow) line shows the actual discharge over the last 1 year period and is labelled Current.

Visually trace the black line across the figure. In this case, the black line marks the daily average, with the range for that day shown in grey. Examine the data and write down which two months have, on average, higher discharge, and which two months have the lowest discharge. You will have to use your judgement to translate the daily data to determine the months with highest flow. Follow the orange line across the graphic, and look at how discharge over the last year has changed.

Step 5: To exit this screen, click on the X located in the top right of the screen.

Groundwater Data

Step 1: Click on the downward trending graph icon to active groundwater level monitoring stations. You may need to zoom out.

Step 2: Locate the two groundwater monitoring well locations to the south of Langley close to Anderson Creek (red diamond in Figure 20.1).

Step 3: Zoom in, and locate the eastern (on the right) of the two wells at this location (Langley 196 St near 36 Ave, Observation Well #353). Click on this well, and then click DOWNLOAD DATA and save the data to your folder (station-data-8309.csv).

Step 4: Click on the Level button on the right. You will see a graph similar to Figure 20.4. Notice that the groundwater data is plotted as depth to water on the y-axis, but it has been plotted as increasing downwards. This is how water levels are measured in groundwater wells, using a specialized tape measure to record the depth to water downwards from the ground surface. A large depth to water therefore means a lower water elevation. Statistical features are as per Figure 20.2. 

Trace the black line across the figure. Write down which two months have, on average, higher groundwater levels (small depth to water) and which two months have lower groundwater levels (large depth to water). If you click on a point on the interactive figure, the values for the month will be displayed.

Step 5: To exit this screen, click on the X located in the top right of the screen.

4. Confirm that you have a folder containing three data files in .csv format, one each for precipitation, discharge and groundwater level.

Examining Data on an Annual Basis

Now it is time to examine how water moves in and out of a watershed on an annual basis. The precipitation and groundwater level graphics were done on monthly basis, but flow was on a daily basis. To assist you, your instructor has calculated flow data on a monthly basis. Obtain the set of mean monthly data covering the calendar year prior to your lab from your instructor. Examine the data and answer the following questions:

5. Examine the annual pattern of rainfall data. Which two months represent the peak inputs of water to the watershed from precipitation? In which month(s) are precipitation inputs the lowest?
6. Which two months represent the peak stream discharge out of the watershed? In which month(s) is discharge the lowest? Earlier, you visually assessed the raw stream discharge data to identify your estimates of the high and low flow months.  Did your choices from the graphs of discharge match the calculated averages data?
7. Which two months represent the peak groundwater elevation? Which month(s) have the lowest elevation? Note: the data record depth from surface; the largest depth to groundwater indicates the lowest groundwater level.
8. How much does the groundwater level change over a year (in m)? What does this water level change represent?
9. What is the lag time between peak precipitation and peak discharge? What is the lag time between peak precipitation and peak groundwater level? Explain what is happening.

In this exercise you will examine the response time between precipitation, stream discharge, and groundwater level on a daily basis to gain an understanding of how quickly discharge responds to runoff and interflow compared to groundwater flow.

Step 1: Download the EX3 spreadsheet from Worksheets and open it. Here you will note that the station data for precipitation, discharge, and groundwater level have been provided from 2004-09-10 to 2020-12-31. You will also note two graphs. First, a graph of precipitation and discharge for the 2019/2020 water year (October 1, 2019 to September 30, 2020) on a single graph, plotting precipitation as a column, and discharge as a XY type joined by a line. An example is shown on Figure 20.5.

Second, you will see a graph of precipitation and groundwater level for the 2019/2020 water year on a single graph, plotting precipitation as a column, and groundwater level as an X-Y scatter plot joined by a line. An example is shown on Figure 20.6.

Step 2: Open your file for climate data (Station-data-12418.csv) by double clicking on the file. You may need to start your spreadsheet program first, and then use File > Open to open the file. This file contains precipitation data, then snowfall data, and then a number of temperature data. You only need the precipitation data, and can delete everything after the precipitation data if you wish. Scroll down the data until you see the data for Jan 1, 2021 onwards. Copy and paste this data into the Precipitation Data portion of your EX3 spreadsheet.

Step 3: Open the file for hydrometric data (Station-data-4268.csv). This file contains both discharge and water level data. You only need the discharge data, and can delete the water level data if you wish. Copy and paste the discharge data from Jan 1, 2021 onwards into the Streamflow Data portion of your EX3 spreadsheet.

Step 4: Open the file for groundwater level data (Station-data-8309.csv). Copy and paste the water level data from Jan 1, 2021 onwards into the Groundwater Level Data portion of your EX3 spreadsheet.

Answer the following questions, and submit all graphs as directed by your instructor:

10. Examine the data that you just copied into the spreadsheet. Are there any problems with this raw data set in either precipitation, stream discharge or groundwater level? What do you think may have happened?
11. The two graphs show Oct 2019 to Sept 2020 as default. If needed, adjust the date range displayed on these graphs to the date range specified by your instructor. Copy/screenshot/snip these two graphs and save to a known location.
12. What time lag typically occurs between larger rainfall events in the winter, and changes in discharge in the Nicomekl River? You may wish to note some larger rainfall events on an annual graph, and adjust the x-axis so that you can zoom in on those dates only. Choose one such event that supports your answer and describe.
13. Examine the graph plotting precipitation and groundwater level data. Does the groundwater level respond to precipitation on a daily basis? Discuss the relationship between precipitation and groundwater level change and the associated lag times. Choose a range of data on the graph of precipitation and groundwater level that supports your conclusion.
14. Groundwater levels rise and fall on a seasonal basis. What happens to the water stored in groundwater between September and February?

In this exercise, you will examine some of the water users within this watershed, and consider what affect their usage has on the stream discharge, and upon the overall nature of the water balance in the watershed. In other words, you will be introduced to the complexity of water management in BC.

The hydrograph and groundwater levels within the Nicomekl River watershed are affected by the use of water by humans living within the watershed. Here, drinking water usage is consistent year-round, irrigation water usage peaks in summer time, and commercial use varies throughout the year.

Figure 20.7 indicates the approximate area of the Nicomekl River watershed (Figure 20.7a) and the locations of licensed surface water (Figure 20.7b) and groundwater (Figure 20.7c) water users within the watershed.

Using Figure 20.7, answer the following questions:

15. Which areas of the watershed use the most surface water? What usage type do you think these water licenses are used for? Are they domestic, water supply, irrigation, commercial? Explain your answer.
16. Which areas of the watershed have single households (domestic use) that rely upon groundwater for their water supply? Explain your answer.
17. Based on the distribution of all of the surface licenses and groundwater wells, can you determine which areas of the watershed have their drinking water supplied from a large water supplier? Explain your answer.
18. Which area of the watershed do you think is the most environmentally sensitive? Why did you pick this area?