EarthCache : The Changing Geology of the Ravine under the Spadina Crescent Bridge, Saskatoon
Coordinates: 52.1298 N, 106.6563 W (approximate centre of the ravine under the bridge)
Location Access Details: Located in Kinsmen Park, Saskatoon, Saskatchewan, Canada — publicly accessible via walking trails.
On-Site Tasks for Logging
While at the site, please complete the following tasks:
1. What visible evidence at the site demonstrates the changing use of the ravine over time i.e. how does human engineering interact with the ravine’s natural geology in this location?
2. What role does sediment transport and bank erosion play in the geology of the South Saskatchewan River valley near Saskatoon?
3. Answer this question: Which of the three processes—glacial melt-water carving, post-glacial channel removal, or modern storm/erosion flow—do you judge as most active at this ravine right now? Explain your reasoning in one or two sentences.
4. Please take a photo of yourself, your geocaching dog, or a personal item such as your GPSr &c to show that you were visiting the "ravine at this location" (face not required) This photo can be inserted into the log after sending answers into the CO.
DO NOT POST ANSWERS IN YOUR LOG. Please don’t provide the answers when logging the cache online except for the photo, for the rest of the queries use the “Send answers” feature OR geocache mail the cache owner including the earth cache GC number, title and the answers. 
Please answer to the best of your ability. As long as you give it your best effort, we'll be happy to accept your responses so you can log your EarthCache! You will probably find the answers you are looking for in this description page! No physical logbook is present. Besides the interpretation provided in the description, there is additional Interpretive Information on-site through signage.
Geologic Context
Visitors to this EarthCache will explore how glacial, fluvial, and human processes combined to create, modify, and use the ravine that the Spadina Crescent Bridge spans. Therefore you will discover how ice, water, and people worked together to shape the ravine under the Spadina Crescent Bridge.The lesson covers:
Glacial legacy and post-glacial shaping: The ravine is a smaller tributary or side-ravine within the larger South Saskatchewan River valley, which itself was carved by glacial and melt-water action and later modified by river flows. In other words, a long time ago, big sheets of ice called glaciers moved across this area. When the ice melted, rushing water carved out valleys and small side-ravines like this one. This is why the land has its slopes and shapes today. The ravine lies within the valley system of the South Saskatchewan River, which formed from Glacial Lake Saskatoon both of which have shaped the landscape around Saskatoon. At the end of the last glaciation, melt-waters carved out post-glacial channel scars—swales and ravines—that later became smaller ravine systems such as the one under the bridge.
The South Saskatchewan River Basin (SSRB) has been shaped by glaciation, melt-water channels, and subsequent river flow. Its valley walls show evidence of erosion and sediment transport, especially near urban centres such as Saskatoon.
Sediment transport, bank stability and human impact: Studies of the South Saskatchewan River show how regulation of flows changed sediment dynamics, leading to bank instability and ravine formation. This might also be explained thusly; rivers carry sand, silt, and rocks as they flow. How the water moves can change the shape of the riverbanks. Sometimes, the banks slide or erode, especially when people change how water flows upstream. Upstream flow regulation and valley processes have altered the sediment regime, leading to observable bank slumping and ravine expansion along the river valley. The underlying Pleistocene glacial deposits, silt, sand, and gravels, combined with post-glacial valley formation, give the slopes a tendency to slump and erode—particularly where river valley walls are steep.
Bank instability and sediment yield studies indicate that human modifications upstream have altered flow regimes, increasing bank slump potential.
Historical and Engineering Aspects
Human re-working of the ravine: The ravine was selected by the City in 1903 for possible sewer outfall owing to its natural drainage; later during the Depression a series of decorative duck ponds were installed in the ravine as part of Kinsmen Park; today the ravine serves storm water, sanitary access (allows access to underground pipes) and recreation.
In 1903, Saskatoon’s city planners purchased the ravine land anticipating a sewer outfall. That plan did not proceed, and instead during the 1930s a Depression-era work project created decorative duck-ponds in the ravine, adding recreational value before being filled in. The Spadina Crescent Bridge was built in 1930 (by Saskatoon Contracting Co.) to span the ravine. Today, sanitary sewer lines run underground along the ravine, with visible capped access. The presence of infrastructure underscores how the ravine’s natural drainage and geotechnical setting remain important.
Ending Note – Bridge & Legacy
Bridge and infrastructure geology highlight: The concrete arch bridge (Spadina Crescent Bridge) and sewer infrastructure demonstrate how built structures interact with the natural ravine geometry and geologic substrate. By looking at the bridge and the ravine, you can see how nature and human design work together over time.
As you look up from the ravine path, notice the elegant arch of the Spadina Crescent Bridge, built in 1930 and upgraded in 2022, now listed on Saskatoon’s Heritage Registry. This single-span concrete arch carries two lanes of traffic over a ravine that once formed part of the city’s functional drainage system and recreational landscape. The bridge is more than a crossing—it is a symbol of the interweaving of geology, hydrology, human planning and infrastructure across time. You are standing at a location where urban design, natural processes and historical change converge.
Geological Terms
Observe the ravine slope beneath the bridge showing the bank face, and note these types of features (e.g., exposed roots, visible layers of sediment, rills, eroded gullies) that indicate slope processes.
RAVINE
A ravine is a deep, narrow valley or gorge with steep sides, larger than a gully but smaller than a canyon, usually formed by the erosive action of running water over time. Ravines often have V-shaped profiles and may contain active or intermittent streams, though some may remain dry. They are typically found in hilly or upland areas where water runoff cuts into soft rock, clay, sand, or gravel. Ravines influence local drainage, provide important habitats for plants and animals, and are shaped by processes such as streambank erosion, sediment transport, weathering, and freeze-thaw cycles.
Alternate names: Depending on the region, a ravine may also be called a cleuch, dell, gill, ghyll, glen, gorge, kloof, or chine.
Formation: Ravines often develop from gullies that deepen over time; when a gully reaches a significant depth—typically over 5 meters (16 ft)—it can be classified as a ravine. Human activity, deforestation, and heavy rainfall can accelerate ravine formation.
RILL
A geological rill is a small, narrow channel or groove in the soil or rock surface, usually formed by the movement of water.
Size: Rills are typically very shallow and small—just a few centimeters to decimeters deep and wide—so small that they can often be smoothed out by normal tilling or erosion.
Formation: They form when running water (rainfall or surface runoff) concentrates in tiny paths, cutting into the soil and carrying sediment downhill.
Difference from gullies: If the water keeps flowing and the channel gets bigger, a rill can grow into a gully, which is larger and harder to remove.
Example: After a heavy rain on a slope, you might see tiny channels carved into the soil on a hillside—these are rills. Over time, if water keeps flowing there, they can deepen and expand.
In short, a rill is like nature’s tiny incision in the land made by water.
Rills are important in studying ravines and river valleys because they are the first signs of water erosion and can reveal how the landscape is slowly being shaped over time. Here’s why:
Early indicators of erosion: Rills show where water concentrates and begins to remove soil. By mapping rills, geologists can see which parts of a slope are most vulnerable to erosion.
Sediment transport clues: Rills carry tiny amounts of soil and sediments downhill. Studying them helps us understand how material is moved from uplands to ravines, valleys, or rivers.
Slope stability insights: A slope with many rills may be at risk of larger erosion features like gullies or landslides. This is important for understanding the safety and longevity of natural ravines or engineered areas near bridges.
Connection to water flow: Rills show how rainfall or snowmelt flows across the land surface, feeding into larger channels and shaping the development of ravines over thousands of years.
Human impact measurement: Comparing rills in natural areas versus urban or park areas can show how human activity (trails, drainage, construction) changes erosion patterns and affects river valleys.
In short: Rills are like tiny footprints of water on the land. By studying them, scientists can predict how a ravine or river valley will change in the future and how to protect it.
Publications Canada
Local soils reports for the Saskatoon map area (73-B) elaborate on Pleistocene deposits of till, sand, silt and organic layers—key to understanding ravine slope behaviour.
Canadian Soil Information Service
Bibliography
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(Retrieved 25 Oct 2025)
City of Saskatoon. (n.d.). History of our bridges. https://www.saskatoon.ca/moving-around/bridges/history-our-bridges
(Retrieved 25 Oct 2025)
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(Retrieved 25 Oct 2025)
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(Retrieved 25 Oct 2025)
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(Retrieved 25 Oct 2025)
Li, L. (2024). Sediment transport modelling of the South Saskatchewan River (Unpublished master’s thesis). University of Saskatchewan — HARVEST Digital Repository. https://harvest.usask.ca/bitstreams/730ce8f1-0400-4c1a-b0b0-40bfbc967622/download
(Retrieved 25 Oct 2025)
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Prairie Farm Rehabilitation Administration / Agriculture and Agri-Food Canada. (n.d.). The soils of the Saskatoon map area (73-B) (CANSIS Publication SKS4). Canadian Soil Information Service. https://sis.agr.gc.ca/cansis/publications/surveys/sk/sks4/sks4_report.pdf
(Retrieved 25 Oct 2025)
Saskatchewan Environmental and Water Assessment Authority (SEAWA). (2009). Geography of the South Saskatchewan River Basin: SEAWA Watershed Report 2009-1. SEAWA. https://seawa.ca/assets/media/documents/SEAWA-Watershed-Report-2009-1-Geography.pdf
(Retrieved 25 Oct 2025)
Saskatchewan River Basin Council / Alberta Innovates. (2016). Climate vulnerability and sustainable water management in the South Saskatchewan River Basin: Final report (WIP-WSWM-2065). https://albertainnovates.ca/wp-content/uploads/2022/06/WIP-WSWM-2065-N-Watersmart-SSRB-Climate-Vulnerability-Final-Report-15Jan2016.pdf
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Spadina Crescent Bridge (Saskatoon). (2025, October 25). Wikipedia. https://en.wikipedia.org/wiki/Spadina_Crescent_Bridge_(Saskatoon)
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The Spadina Crescent Bridge — Historic span in Saskatoon. (2010, July 19). Saskatoon StarPhoenix. https://www.pressreader.com/canada/saskatoon-starphoenix/20100719/282647503796343
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University of Michigan Tech — Keweenaw Geoheritage. (n.d.). EarthCache (MiTEP) — Educator resources. Michigan Technological University. https://www.geo.mtu.edu/KeweenawGeoheritage/MiTEP_ESI-2/EarthCache.html
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Further Reading / Related EarthCaches (Alphabetical Order)
Cypress Hills — Conglomerate Cliffs. GC62F7B. https://www.geocaching.com/geocache/GC62F7B
(Retrieved 25 Oct 2025)
Cypress Hills — Massif / Plateau Edge. GCN09W. https://www.geocaching.com/geocache/GCN09W
(Retrieved 25 Oct 2025)
Kentville Ravine EarthCache (Nova Scotia). GC5T5QK. https://www.geocaching.com/geocache/GC5T5QK
(Retrieved 25 Oct 2025)
Mud Creek EarthCache — Creek / Gully / Ravine Processes. GC5DZC4. https://www.geocaching.com/geocache/GC5DZC4
(Retrieved 25 Oct 2025)
Riverbend Archaeological Site (Edmonton — near Whitemud Ravine). GC4WTMA. https://www.geocaching.com/geocache/GC4WTMA
(Retrieved 25 Oct 2025)
Teays River / Ancient Spillway EarthCache. GCPAFH. https://www.geocaching.com/geocache/GCPAFH
(Retrieved 25 Oct 2025)
White Mud Clay (Eastend, SK). GC5EA62. https://www.geocaching.com/geocache/GC5EA62 (archived)
(Retrieved 25 Oct 2025)
Whitemud Ravine — Mineral Springs / Ravine (Edmonton area). GC20EVQ. https://www.geocaching.com/geocache/GC20EVQ
(Retrieved 25 Oct 2025)