From the Ground Up. Water, Geology, and Wetlands EarthCache

To log this Earth Cache, please answer the following questions 

1. Based on the information on the cache page, what are two advantages of a constructed wetland?   What is one disadvantage of a constructed wetland?

2. Describe a purpose of a constructed wetland.

3. Based on the information provided, what is the main factor based on the geology of the area that caused developers to consider building a constructed wetland?

4. Take a picture of yourself, your GPSr with Olds College Botanic Gardens & Constructed Wetlands in the background  (face not required)  You may provide the photo in your earthcache geocaching log of your visit.

5. Now for fun!  What is your favorite pastime when observing and visiting the Olds College Botanic Gardens & Constructed Wetlands?

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.  You will probably find the answers you are looking for in this description page! You will probably the answers you are looking for in this description page!

The Botanic Gardens and Constructed Wetlands are open to the public free of charge from dawn until dusk during the gardening season (May to October). Dog (on a leash) friendly too.  In the winter months, the central area of the gardens remains open, while the eastern section is closed. Donation boxes are located at each entrance, with a suggested donation of $5. All contributions help support the continued care and maintenance of the gardens.  Whereas the wetlands are fun to observe during the seasonal opening months, please post a picture at the gates for your log  in the "off-season" and try to return May to October if you can ;-)

The Geology Behind Olds College Botanic Gardens & Constructed Wetlands: A Water Treatment System

The Olds College Botanic Gardens and their constructed wetlands covering 15 acres, and a network of 19 interconnected ponds are much more than just a picturesque escape into nature—they are also a cutting-edge example of how geology plays an essential role in solving modern environmental challenges. Let's explore the geology behind the wetlands, what makes them unique, and how geologists and engineers collaborate to design and maintain these incredible systems.

At the heart of the Olds College Botanic Gardens & Constructed Wetlands project is a commitment to creating sustainable water treatment solutions that benefit both the environment and the community. This educational initiative not only provides a place to observe nature, but it also highlights the vital role that geology and earth science play in shaping solutions to challenges such as water conservation, wastewater treatment, and landscape rehabilitation.  As urbanization increases, so does the need for better water treatment solutions. Constructed wetlands, with their geological foundations and biological processes, offer an innovative and low-cost method for treating wastewater, stormwater, and other contaminants. By mimicking nature’s filtration systems, constructed wetlands help improve water quality, reduce flooding, and if well managed will also happen to provide a habitat for wildlife.

What Are Constructed Wetlands?

A constructed wetland is an artificial ecosystem designed to mimic the processes that occur in natural wetlands. These man-made systems are used to treat water, especially wastewater or runoff, before it returns to rivers, lakes, or aquifers. The wetland uses plants, microorganisms, and soils to filter out pollutants like suspended solids, nitrogen, phosphorus, and even harmful chemicals like hydrocarbons or heavy metals.

Constructed wetlands are designed to replicate the filtration capabilities of natural wetlands, but with human intervention to ensure they can handle specific water treatment needs. The goal is to improve the quality of water before it enters larger water bodies, ensuring cleaner, healthier ecosystems for both humans and wildlife.

The Geological Importance of Wetlands

Wetlands, whether natural or constructed, are powerful geological features. In fact, wetlands are geological landforms—special areas where water collects and saturates the ground. Wetlands are not only biologically significant but also play a crucial role in geological processes by storing water and influencing groundwater flow.  At Olds College, hydrologists and geologists work together to design the wetland’s "cells"—distinct sections within the wetland that allow for different treatments of water. The wetland’s design must account for factors such as the volume of water, the rate at which it flows through the system, and how long it stays in each area before moving downstream. Geologists consider factors like hydraulic residence time (the amount of time water stays in the wetland) and groundwater exchanges (how groundwater interacts with surface water) to ensure that the system is as effective as possible at filtering out pollutants.

Constructed wetlands like the ones at Olds College play a critical role in water conservation and quality improvement. These systems are designed to remove pollutants such as suspended solids, nitrogen, phosphorus, and even metals from wastewater. They rely on plants, microorganisms, and soil to absorb or break down these contaminants, making the water cleaner before it is released back into the environment.

Geologists help design these systems by ensuring the site’s geology supports efficient water treatment. For example, they may choose soil types that can filter out certain pollutants or create sloped sections to allow water to flow at the right speed.  For the constructed wetlands at Olds College, the geological properties of the land determine how water moves through the system, how it filters out contaminants, and how water can be naturally returned to the groundwater. Let’s take a look at some of the geological features that shape this area.

A sample schematic of a constructed wetlands.

The Geology Beneath the Constructed Wetlands

The land surrounding Olds College and its constructed wetlands is rich in geological history. Beneath the surface, geologists identify four distinct rock units, each with its own properties. These units are important because they affect the way water moves through the soil and rock layers, influencing both groundwater flow and the filtration abilities of the wetland system.

The sequence of rock units consists of:

(1) a layer of glacial till, fractured coal, and shale bedrock, identified as the ‘shallow aquifer, A1’;

(2) fractured and uneven shale bedrock, called the ‘first aquitard, T1’;

(3) a significant coal seam, known as the ‘coal aquifer, A2’; and

(4) an unfractured shale bedrock layer, classified as the ‘basal aquitard.’

The geological layers in this area are crucial to understanding how water behaves. By studying these layers, geologists can predict where and how water will move, which is essential when designing effective constructed wetlands for wastewater treatment.

Aquifers and Aquitards: Water Storage and Flow

The geology beneath the constructed wetlands at Olds College involves two key geological features related to water flow: aquifers and aquitards. To understand how groundwater moves, and why it behaves the way it does, it's important to first define these terms:

What is an Aquifer?

An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (such as gravel, sand, silt, or clay) from which groundwater can be extracted. Simply put, aquifers are huge natural water storage units that allow water to flow through them. Aquifers are classified into two main types:

• Unconfined Aquifers: These aquifers are located near the earth's surface, where the water can flow freely from the aquifer to the surface via springs, wells, or the water table. Gravity (zero pressure) is the primary force behind the movement of water in unconfined aquifers, which is why they often have a constant water level. The water in these aquifers naturally moves downward and out, depending on the surrounding topography.
• Confined Aquifers: Unlike unconfined aquifers, confined aquifers are trapped between layers of impermeable rock or clay, which prevent the water from reaching the surface naturally. Water stored in confined aquifers is under pressure because it is confined between layers of less permeable materials. To access the water, a well must be drilled down to the aquifer. When drilled, the water may flow up the well due to the pressure, even without the need for pumping.
• In a regional flow system, water moves downward at the main divide and upward at the drainage basin's base. An unconfined flow system is influenced by the overlying water table, whereas a confined system is not. Recharge areas allow water to enter the aquifer, while discharge areas remove it. In the Paskapoo Formation below the Town of Olds Alberta, the absence of confined aquifers means groundwater follows unconfined flow patterns, with movement governed by the landscape and interconnected hydraulically at each point.  In other words, the Paskapoo Formation lacks continuous confined aquifers, so groundwater movement follows unconfined flow patterns controlled by local topography, with each point in the system being hydraulically connected.

What is an Aquitard?

An aquitard is a layer of rock or sediment that restricts the flow of groundwater between aquifers. These layers are often composed of materials like clay or impermeable rock masses, which do not allow water to pass through easily. While an aquifer stores and allows water to flow, an aquitard acts like a barrier, controlling the movement of water between different aquifers.

In the case of the constructed wetlands at Olds College, understanding these geological features is critical. The layers of aquifers and aquitards beneath the site help determine how water flows through the landscape, how it is stored, and how it can be filtered and purified by the wetland system.

A sample schematic diagram of Groundwater Flow.  Groundwater recharge, also known as deep drainage or deep percolation, is a hydrological process in which water moves downward from surface water into the groundwater.  When the water in an aquifer reaches a specific saturation point, it can flow out of the ground and enter surface water bodies, a process known as groundwater discharge. Consider the role of a constructed wetlands on groundwater.

Geology’s Role in Wetland Design

The layout and efficiency of constructed wetlands depend heavily on the topography (shape of the land) and geology of the site. Natural wetlands work best in low-lying, flat areas, where water naturally collects and moves slowly through the land.  If a site already has wetlands or if water naturally collects in the area, then that site may be unsuitable for a constructed wetlands—because the water may be flowing and draining too quickly, or the area might not be able to support additional water flow. 

Wetland shape is dictated by the existing topography, geology, and available land. Geologists study these aspects carefully to create wetland systems that efficiently manage water flow, filtration, and retention.

When designing a constructed wetland, several hydrological factors are considered:

• Hydraulic residence time: the amount of time water spends in the wetland
• Water balance: understanding how much water enters and leaves the system
• Groundwater exchange: how water moves between the wetland and the groundwater system

These factors are crucial for designing wetlands that can treat water effectively while working with the natural flow of groundwater.

Wetland Landforms and Water Treatment

Natural wetlands are unique because they are biological landforms which arise in low lying areas created by geological processes—Natural wetlands are formed by living organisms and their interactions with the physical environment. Plants, microorganisms, and animals all play roles in shaping wetlands and helping them purify water.

Geological formations are primarily shaped by physical processes like erosion or deposition, and natural wetlands are shaped by biological processes. In this sense, constructed wetlands are a blend of both geology and biology. Geologists help design the layout of the wetland and how to arrange the soil and sediments to optimize water treatment.

Plants in the wetlands help filter out contaminants, while microorganisms in the soil break down harmful substances like oils or pesticides. Together, these biological processes work to make the water cleaner before it is released into rivers or groundwater supplies.

The Role of Geologists in Constructed Wetlands

Geologists are at the heart of the success of constructed wetlands. They help determine the best locations for the man-made wetlands by studying the land's geology, hydrology, and soil types. Without the expertise of geologists, the wetland system would not function as effectively.

Geologists also monitor the groundwater flow and water retention in the wetlands to ensure they are performing as expected. They use their knowledge of local geology to predict how water will behave within the wetland system and help optimize water flow to prevent flooding or contamination.

The Future of Water Treatment: Geology and Sustainability

The work done at the Olds College Botanic Gardens and their constructed wetlands demonstrates the important role that geology plays in environmental sustainability. Geologists are crucial for designing and managing systems that not only treat water but also contribute to the replenishment of groundwater, a valuable resource.

Wetlands and aquifers are vital to maintaining water quality and ecosystem health, with wetlands acting as natural filters and aquifers providing essential water supplies.  The relationship between natural and constructed wetlands with aquifers is deeply interconnected, with wetlands relying on aquifer outflows for water, and in turn, wetlands helping to recharge aquifers through seepage. To prevent a water crisis and sustain both human and environmental needs, immediate action is necessary to restore and protect wetlands, aquifers, and catchment areas.

As concerns over water quality and availability continue to grow, the integration of geology and wetland science is becoming increasingly important. Geologists, engineers, and environmental scientists will continue to collaborate to find innovative ways to manage water resources, reduce pollutants, and support sustainable agricultural and industrial practices.

By visiting the Olds College constructed wetlands, you can experience firsthand how earth science is applied to solve environmental challenges. It’s a unique opportunity to witness the integration of biology, geology, and engineering in action. The wetlands are a reminder of the critical role that geologists play in maintaining the health of our planet’s water systems.

For more information:

Constructed Wetlands

Botanic Gardens & Constructed Wetlands

Constructed Wetlands for Research, Training, and Industry Support at Olds College

Water & Wastewater

Alberta Guide to Wetland Construction in

Stormwater Management Facilities

Groundwater Geology, Movement, Chemistry, and Resources near Olds, Alberta Alberta Geological Survey.