Laurel Creek Tour

This lab will introduce you to an aquatic ecosystem in Waterloo that has been heavily impacted by human, agricultural, and urban activity. We will go on a virtual tour of the Laurel creek watershed. The purpose of this lab is to understand how water quality changes, and factors that contribute to water health. At the end of this virtual tour you will understand how surrounding land use impacts the water quality, as well as water quality indicators examined to determine health.

Laurel Creek is a sub-watershed of the Grand River watershed. It is 74.4 km2 in length, starting in an agricultural area, then meanders throughout the city, along private properties, Waterloo park, underneath the uptown Waterloo city district and vegetated wetland and forested areas. Below is an overview map of the stops we will take on the tour. The maps are interactive, meaning you can zoom in and out, and navigate around the area. Throughout this tour we will be using terminology related to water quality and sampling. A document explaining the terms is provided on learn. Read it before you start this lab, and refer to it when needed.

Here is an overview of the stops on our virtual tour:

The learning outcomes of this lab are to:

· Assess the aquatic condition of Laurel Creek and understand the contributors to its health.

· Identify the differences between lotic and lentic systems along Laurel creek.

· Understand impacts of surrounding land use on Laurel Creek's health.

· Learn about the purpose of reservoirs and their benefits and drawbacks related to ecosystem health.

· Learn about the issues surrounding Silver Lake reservoir, the environmental assessment process, and remedial measures taken.

Let's take a look at our first stop!

Laurel Creek headwaters are easily seen here at this stop, located along Wilmot line on the border of the city of Waterloo. The creek originates as a spring seepage on private property just northwest of this area. Although there is evidence of anthropogenic impacts at this location, it is still a relatively natural ecosystem.

Consider the water quality at this location. Viewing the media provided on this tour, think about what would influence the stream's health. We refer to these observations as site features, where surrounding land use, topography, and vegetation are recorded.

The wetland ecosystem that Laurel Creek runs through acts as a sponge to absorb fluctuating water levels and helps in alleviating potential flooding. Tree and shrub species such as dogwood, tamarack, and cedar are present and tolerate this wet environment. This dense vegetation cover maintains the area as a collector for precipitation runoff and promotes organic matter accumulation. Viewing the surrounding land use, there is relatively little soil compaction when compared to the other sites along this tour, with the exception of the gravel road.

Focusing on the creek itself now, it would be characterized as lotic because of its fast running waters (also referred to as high velocity or stream flow). The water has high oxygen content as a result of the riffles created when the water runs over the gravelly substrate of the stream.

The dense vegetation not only helps with flood control, but also serves as an important year-round habitat and resting area for wildlife. The vegetation provides shade along the creek and keeps water temperatures cool, which is important for aquatic life. In addition, it helps stabilize banks and prevents sediment and nutrients from entering the creek.

Overall, vegetation is key to Laurel Creek's health by limiting severe water fluctuations, limiting sediment and nutrient loading, keeping the water cool, and thereby maintaining healthy levels of dissolved oxygen.

Although we classify the creek at this stop as relatively natural, there are still human impacts. The creek is channelized under Wilmot line through the road culvert. This metal structure prevents infiltration and creates a loss of stream margin. There are two culverts, one is for water overflow which dries up after a flood occurs. This is an equalizing culvert which is essential to maintaining hydrology of upstream and downstream habitats. The gravel road introduces oil, road salt in winter months, and Calcium Chloride for dust control in summer months. This is a rural area and the surrounding agricultural fields input a runoff of nutrients, cattle waste, sediment, and pesticides into this environment.

Note that this area serves an important hydrological function, as we are situated on a moraine of well drained substrate soil. Precipitation infiltrates into our aquifer to recharge our drinking water source.

Welcome to stop #2, Laurel Creek Reservoir. This reservoir bears fluctuating water levels as the Grand River Conservation Authority (GRCA) mitigates flood risk. During the spring and summer, the reservoir fills up and and is available for recreational activities such as canoeing and swimming, as part of the Laurel Creek conservation area.

In late fall, dams are altered to draw down water levels in order to accommodate spring melt and precipitation. There are many reasons a reservoir is created such as flood control, drinking water supply, recreation, low flow augmentation, firefighting, and hydroelectric power.The purpose of this reservoir is for flood control as are all reservoirs in our GRCA watershed, with a secondary focus on recreational usage and aesthetics.

Further downstream is another reservoir you may be more familiar with, Columbia Lake. This is part of the UW north campus, located on the corner of Westmount road and Columbia street. Look around the area, consider the surrounding vegetation, including along the shoreline and beyond. Cattails, dogwoods and other wetland species line the edge of the reservoir. Observe the possible pollution sources in the area, indirect or direct.

The city of Waterloo has built subdivisions upstream and near the reservoir which will contribute to urban runoff of pollutants, sediments, warm water, and high water volumes from the impervious surfaces. The creek was channelized to flow underneath the Beaver creek road and the runoff from the road impacts the health of the creek. Consider the role of a reservoir and fluctuating water levels. This increases sedimentation, creating murky sediment laden water, erodes water banks, and impacts aquatic and terrestrial wildlife habitat (think about the frogs and turtles hibernating in the mucky substrate, shorebirds nesting in the cattails).

This stop can be regarded as a “breakpoint” where Laurel Creek becomes a warm water stream, or moves from a rural to an urban stream. In terms of the water quality, this is a lentic system. The dissolved oxygen level is low due to the relative absence of riffling and shading, and the turbid, expansive, open water will trap the sun’s UV rays and increase water temperature. Only aquatic life that can tolerate poor water quality can survive here, for example midge larvae (which are benthic invertebrates) and carp.

Welcome to stop #3. This is a small reservoir artificially created within Laurel creek, called Silver Lake, located adjacent to Waterloo Park. This reservoir is historically significant as Waterloo's first settler, Abraham Erb operated a grist mill using hydro power. The photo below depicts a replica of the original mill. The original mill was a social and economic centre that encouraged settlement in Waterloo and was used to harvest ice in the late 1800s, as well as to grind grain for the Seagram distillery.

This is the last view of the water before it is channeled underneath the infrastructure of uptown Waterloo. It resurfaces after Regina street and then drains into the Grand River several kilometers downstream. Think about the areas it has flowed through (the rural headwaters, UW campus, park) and how the water is impacted along the way.

Look around this area, consider what impacts the land use has on this section of the creek. There are inputs from these adjacent land uses. This lake is near Waterloo Park, a popular attraction that includes a boardwalk around the reservoir and a small animal farm, the perimeter institute, barrel loft condominium development, LRT, biking and walking paths, picnic areas, and parking lots.

Take note of the cascading outlet weir that was designed to concentrate low flows and to accommodate 100-year flood events. The cascade is aesthetically pleasing and allows aeration, as it acts like a mini waterfall.

The vast urban area of impervious surfaces results in road salt runoff, sediment loading, nutrient runoff and heating of precipitation. All of these pollutants are channeled through storm drains.

Before the water enters Silver lake, at least some of the storm drains would have a catch basin with an oil and grit separator which removes most of these pollutants and controls the release of water into Silver Lake. Given the surrounding land use, the water quality of Silver lake is poor and is a lentic system.

The water is warm, stagnant, sediment laden, has a silty substrate and small riparian area to buffer surrounding land use impacts.

Inputs from land use upstream is concentrated in the reservoir resulting in high nutrient levels. Silver lake has low biodiversity and invasive species (phragmites, European buckthorn), as well as pollution tolerant aquatic life such as carp. The predominance of introduced species is caused by management practices (e.g. mowing to lake edge) and surrounding human activity.

Watch the video below which shows Silver Lake from the east end (just past the grist mill) to the boardwalk on the north end. Here, you will see the vegetation and the riparian area around the lake, notice the small riparian zone as well as many non-native plant species.

Silver Lake has been assessed over the years. In 1993, a watershed study was done on Laurel Creek by the Grand River Conservation Authority, which identified upstream and downstream influences on the water. Recommendations were aimed at reducing flood risk and improving water quality. Suggestions for water quality improvements included changing stormwater and agricultural management practices, improving the water quality of reservoirs, rehabilitating degraded sections of the creek, and monitoring of the area. Silver Lake, Laurel Creek Reservoir, Columbia Lake, and Laurel Lake were the reservoirs identified that needed improvements. This study was endorsed by Waterloo City Council and integrated into the official plan.

In 2018 a Silver Lake and Laurel Creek environmental assessment (EA) was completed. The scope of the EA was to determine a preferred rehabilitation option for Silver Lake and Laurel Creek within Waterloo Park taking into account flood control, hydraulic capacity, operations, maintenance, water quality, aquatic habitat, aesthetics, public input, safety, social, heritage, cultural and recreational uses. The study identified and evaluated alternatives for enhancing and protecting the ecological function and natural features within the park to ensure that Silver Lake and Laurel Creek continue to be key attractions in the city.

With the newly drafted environmental assessment and several open consultation meetings, further improvements to Laurel Creek and Silver Lake were approved. The $9 million project is currently underway with channel improvements along Laurel Creek from the LRT tracks to University Avenue which will improve fish habitat, terrestrial ecology, the vegetative community and reduce erosion. Silver Lake improvements include removal of 30,000 cubic metres of accumulated sediment, or 3,000 dump truck loads, reconfiguration of the shoreline, and construction of a sediment forebay to manage future sediment issues. View the most recent video clip below of how Silver Lake is being dredged, a stark contrast from how it used to look!

The pools will be separated by rock 'reefs' to restrict movement and maintain cooler bottom temperatures. A deep channel lined with big rocks will be created from the intake to direct stream flow through a submerged pipe to be discharged at the outlet. This will help prevent sedimentation and warm water mixing with cooler water. Naturalized plantings will be placed along the northwest shoreline, as well as a small sandy section to provide a breeding area for turtles. A deeper channel or pipe will be constructed along the lake-side of the boardwalk.

Welcome to stop #4, the first point that Laurel creek enters the UW campus. Directly upstream is a busy road, Columbia street, with Columbia lake on the other side of the street. Columbia Lake is a reservoir that is used for flood control and aesthetics. Look around the area and consider the possible sources of pollution inputs at this section of the creek. These sources include inputs from the street, campus ring road, campus life and student residences (Ron Edyt Village-REV).   

The riparian zone is dense with vegetation that includes a mixture of native, naturalized, and introduced plant species. This vegetation buffer along the creek could be wider, but the property is regularly maintained (cut) by the UW Plant Operations. There are various species in the riparian area such as silver maples, willows, milkweeds, goldenrods, mayapples, and cattails, that can tolerate the wet environment and help with flood mitigation. There are some introduced species, such as oxeye daisies and dame’s rocket which were likely introduced by the field management practices. 

The surrounding area is impacted by impervious surfaces such as roads, parking lots, and buildings. This surrounding land use solidifies the importance of the riparian area to mitigate runoff into the creek.  The water has a high velocity and there is a small riffle just downstream of the outlet of the dam (where Columbia lake reservoir travels underneath Columbia Street and onto campus), which means there is high dissolved oxygen at this point.  

This reservoir is controlled by weirs which are installed or removed to control the water levels. This helps control the flow, however, sediment and debris (eg. large pieces of wood) build-up behind the weir. When the weirs are removed the creek’s water levels on campus increase very quickly. 

At the time of weir removal, typically late fall, the sediment from the reservoir flushes through the system, being deposited at bends and meanders along the creek, as we will observe at the next stop. 

Sediment transport from the reservoir also occurs during times of high precipitation. The substrate of the area is clay with pebbles and cobble. Overall, this is a lotic system with fair water quality. 

Welcome to stop #5, your final stop on the tour, located on UW campus. This is the final section of Laurel Creek that runs through the Waterloo campus, so consider campus life and its impact on the creek. 

In addition to the Columbia Lake reservoir, there are 2 reservoirs on campus: The Health Services Pond and Laurel Pond. Impervious roads, buildings, loading docks, parking lots and walking paths contribute chemicals to the sediment (from vehicles and road salt) and high volume precipitation runoff.

There is a large population of Canadian geese on campus and their waste contributes phosphates, nitrates, and bacteria to the water. This creates murkiness that lowers dissolved oxygen, reduces habitat quality for aquatic life and increases water temperatures.

This, along with the flood control measures from weirs and dams upstream, all impact Laurel Creek’s water quality.

The riparian zone of this area is covered in dense vegetation such as goldenrods, ash trees, and willow trees, which are suited for this wet environment. This vegetation will help absorb precipitation and control flooding. 

Note the stormwater management pond adjacent to this site. The purpose of the stormwater management pond is to trap sediments and chemical runoff from the nearby parking lot and road. The debris settles to the bottom instead of releasing directly into the creek. When there is an overflow of water in this pond, only the water will drain into the creek and not the sediments. 

The water in this area is slow moving to stagnant with a mucky, silty substrate and high turbidity, meaning it’s very murky. There is a small riffle just upstream which will increase levels of dissolved oxygen but cannot be sustained with the sediment loading. The location is on a bend, (also called a meander) where the sediment deposits builds up. Murky water traps the sun’s UV rays and results in warmer temperatures and lower oxygen levels. The water quality here is poor and only pollution tolerant aquatic life will thrive in these conditions. 

That concludes our tour! Thanks for joining, don't forget to read the Laurel Creek part 1 PowerPoint, and complete your assigned activities!

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