August Nature Lover - Yonge Street Aquifer EarthCache
August Nature Lover - Yonge Street Aquifer
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Logging of this Earthcache likely requires a method of transport; it can be logged on foot. Technically...
What is the Yonge Street Aquifer?
The Yonge Street Aquifer refers to a system of deep regional aquifers that extend in part along Yonge Street, from the Town of Aurora in the south, to the Town of East Gwillimbury in the north. These aquifers are separated by a number of aquitards. From a hydrogeological perspective, the Yonge Street Aquifer is a regional recharge area characterized by a hummocky surface and permeable soils which collect and infiltrate precipitation through a network of channels, tunnels and subterranean lenses of sand and gravel into three aquifers at increasing depth beneath the surface.
Aquifers are formations that contain sufficient permeable material (for example sand, gravel) to yield usable quantities of water to wells. Aquitards are formations inhibiting the movement of water.
Why is the Yonge Street Aquifer important?
York Region’s drinking water includes a blend of surface water from Lake Ontario and Lake Simcoe, as well as groundwater from regional aquifers. The Yonge Street Aquifer is a critical source of drinking water for the Towns of Aurora, Newmarket and East Gwillimbury.
How much water is drawn from the Yonge Street Aquifer?
There are currently 14 Yonge Street Aquifer wells. They cannot pump at their maximum permitted capacities due to a number of reasons; one reason is that sand often enters the well which results in issues with pumps and screening equipment. The maximum permitted capacity of the Yonge Street Aquifer Wells is 87.7 million litres per day. The actual capacity of the Yonge Street Aquifer Wells is 82.5 million litres per day. The total reduction in capacity of the Yonge Street Aquifer Wells is 5.2 million litres per day. As a result, additional well sites were required and suitable locations were surveyed and investigated.
What makes a site a suitable location for a well?
The determination of a suitable well location takes hydrogeological and non-hydrogeological concerns into consideration. Criteria includes:
Groundwater Quantity
• Geological or hydrogeological conditions
• Potential average well capacity
• Potential estimated aquifer thickness
• Apparent transmissivity (estimated rate of groundwater flow within aquifer)
Groundwater Quality
• Land uses within one kilometre
• Potential for land use to effect groundwater quality, for example threats
Natural Environment
• Proximity to wetlands and streams
• Thickness of the aquitard below the shallow aquifer
Well Interference
• Local private well density
• Distance to Permit to Take Water sources
Water Supply System Integration
• Infrastructure and distribution requirements
Site Development Logistics
• Property ownership
• Adjacent existing and future land uses
• Property size
• Property access
It was determined that the Aurora Well #5 location would be best suited for a new production well site; this location also has existing water supply infrastructure.
What is hydrogeology anyway?
Hydrogeology (hydro- meaning water, and -geology meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust (commonly in aquifers). The term geohydrology is often used interchangeably. Some make the minor distinction between a hydrologist or engineer applying themselves to geology (geohydrology), and a geologist applying themselves to hydrology (hydrogeology).
What are the geological characteristics of the posted coordinates (Aurora Well #5)?
This graphic easily shows why sand is a major consideration when pumping from a well that is sourced by the Yonge Street Aquifer!
Are there many wells accessing groundwater in the region?
The graphic below shows various municipal wells in the region; the hydrogeology of each well may be different from those that access the Yonge Street Aquifer. There are over 40 wells that are used for both pumping (i.e. water supply) and for monitoring of the Yonge Street Aquifer.
By the way.. wells that access the Yonge Street Aquifer do *not* look like this... :)
How Do I Log This Earthcache?
1) Start at the posted coordinates (Aurora Monitoring Well #5).
2) Make a note of the elevation at this location.
3) Travel north to Newmarket Well #15.
Landmark at Newmarket Well #15
4) On your journey, observe and make note of the potential contaminants and hazards that you perceive could have an impact on the hydrogeology of the area covered.
5) At Newmarket Well #15, make a note of your elevation.
6) From Newmarket Well #15, turn around (moving south, then east) and travel to Newmarket Well #14.
Landmark at Newmarket Well #14
7) On your journey, observe and make note of the potential contaminants and hazards you perceive that could have a noticeable impact on the hydrogeology of the area covered.
8) As you approach Newmarket Well #14, make a note of your elevation.
Contact the cache owner via the profile page with answers to the following questions.
Do not post the answers with your log!
Q1) Using observations made during your journey, provide at least 8 potential hydrogeological contaminants/hazards that you encountered that may be impactful to the Yonge Street Aquifer.
Q2) Provide one hydrogeological consideration (from the criterion listed above) for each of the three well sites you visited that would be notable if location suitability assessments were being performed today.
Q3) Provide the direction (i.e. north/south/east/west/north east/south east/north west/south west/other) of the watershed drainage using the elevation information you gathered at each of the well sites.
Q4) Provide your opinion as to which terrain feature/installation (NOT the MacKenzie Marsh!) within 1km of Aurora Well #5 likely has a significant recharging effect on the Yonge Street Aquifer.
Additional Hints
(Decrypt)
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Treasures
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