Monitoring Groundwater
In the Ganaraska Region Conservation Authority (GRCA) Watershed, groundwater is an invaluable resource that must be sustainably managed. The GRCA has developed and currently implements a comprehensive groundwater program. The program consists of several projects and initiatives aimed at enhancing the understanding, protection, and management of groundwater resources within the authority’s watersheds. These projects include groundwater monitoring, modeling, surface water and groundwater interaction, as well as data collection and technical support activities. Data collected and analyzed through the groundwater programs is used in local planning initiatives including drinking water source protection, watershed plans and fisheries management plans.

As part of the GRCA watershed wide integrated monitoring program, the main objective of the groundwater monitoring project is to quantify groundwater level fluctuations, groundwater flow directions and gradients, monitor groundwater quality at selected locations, and record changes over time.

The groundwater monitoring project includes the following:

Provincial Groundwater Monitoring Network (PGMN) Wells

A number of recent studies conducted in Ontario have suggested that groundwater resources are under increasing stress from factors that affect both water quality and quantity. Long-term integrated groundwater monitoring programs are needed to address these issues. In 2001, the Ontario’s Ministry of the Environment (MOE) initiated the development of a Provincial Groundwater Monitoring Network (PGMN) in partnership with conservation authorities and a number of municipalities across the province. The PGMN program focuses on monitoring of water level and water quality in selected and instrumented monitoring wells within each conservation authority. Data generated from this network provides supporting background information for groundwater resource management areas such as drought response, scientific modeling, water policy development, and land use planning.

The GRCA has been actively involved with the PGMN program since September 2001. PGMN monitoring wells were selected to monitor ambient conditions in shallow and deep aquifer systems. To date, 17 wells across the GRCA watersheds have been incorporated into the network, 15 of which are instrumented with automated water level monitoring and telemetry equipment, and 2 with manual download stations. Dedicated water quality sampling pumps were installed in 11 wells. Annual groundwater samples are also collected from the majority of the wells and analyzed for water quality parameters. The PGMN wells provide necessary baseline data and aid the GRCA in making informed land use planning and sustainable groundwater management strategies.

Base Flow Monitoring

The groundwater system supports aquatic species and their habitats by providing baseflow to the rivers and creeks. Baseflow is defined as that portion of the total flow within a stream section that is derived exclusively from groundwater discharge. Following a period of little or no precipitation, essentially all flow within a river system can be baseflow, notwithstanding possible anthropogenic inputs (e.g. such as the release of water from various sources of surface storage, ponds, and storm water sewers). Baseflow contributes to habitat conditions that support a healthy aquatic ecosystem. Changes to the quantity and quality of groundwater discharge can affect the aquatic ecosystem. Monitoring of low flow in local streams is particularly important for the management of water resources since demand for water usually increases during dry weather. As a result, streamflow may approach the minimum requirements to sustain ecological or water quality functions. Groundwater discharge is often concentrated in particular areas as a result of changes in topography, geology, and the nature of the groundwater flow regime.

GRCA technical staff and students monitor baseflow during summer seasons when precipitation is expected to be low. Suitable sites selected for the spotflow monitoring are intended to be generally representative of entire watersheds or smaller catchments in a subwatershed.

The Oak Ridges Moraine Groundwater Program

GRCA is a proud and dedicated partner agency in the Oak Ridges Moraine Groundwater Program. This program was established nearly 20 years ago to manage groundwater data consistently across watersheds that originate from the Oak Ridges Moraine. The ORMGP study area includes a significant portion of the GRCA Watershed.

ORMGP is one of the most comprehensive, actively managed water programs in Canada. Its innovative, interactive mapping website provides GRCA staff with access to not only raw monitoring data, but also a library of relevant consulting, government and research related reports, coupled with powerfully interpretive graphs and maps — all designed to assist in making faster and more effective water management decisions.

Partner agencies, such as GRCA, work collaboratively with ORMGP to ensure that data and watershed studies are up-to-date. This allows for more focused GRCA-held data to be integrated with other more regional datasets to enhance understanding of water movement within the watershed.

The ORMGP website provides one-window public access to significant water and geology related data holdings, including maps of wells, water table mapping, geological mapping and long term water level monitoring data, to name a few. Anyone interested in water related data within the GRCA watershed is encouraged to visit the ORMGP website. www.oakridgeswater.ca

Aquatic Monitoring

Fish community monitoring follows the Ontario Stream Assessment Protocol (OSAP) and uses back-pack electrofishing methodology. Each fish is measured for length, weighed, identified to species, and released back into its environment. This data informs us of the proportion of fish that are tolerant or sensitive to changes in habitat, changes in temperature, and the amount of trophic structure at a site. Many factors influence fish community, including the amount of riparian vegetation and urban development nearby. Riparian vegetation shades the stream which helps to reduce the water temperatures, it decreases erosion and improves water quality by filtering surface runoff. Urban development results in the increase of impermeable surface which increases the amount and flow of surface water which can negatively impact the water temperature and reduce water quality by transporting road salts and other chemicals from hard surfaces to the stream. The fish community living in a stream ecosystem is an excellent indicator of these impairments.

 

The information collected from the fisheries monitoring is used to identify and prioritize restoration areas. GRCA is a partner of the Trout Unlimited Reconnecting Canada Initiative, where we are working to improve fish habitat in numerous ways, including the removal of barriers. Over the years GRCA has been involved with many barrier removals, including the Cobourg Creek Rocky Ramp which was completed in 2010, and in 2018 a private dam. The benthic macroinvertebrates are considered animals without backbones that are visible to the unaided eye and that live on, under, and around rocks and sediment on the bottom of lakes, rivers, and streams during some period of their life. Benthic invertebrates are useful biological indicators of water quality and stream health as they inhabit the stream over a portion of their life cycle, thereby reflecting impairments to water and stream quality. Similar to the fish community, there are many factors that influence the benthic community.

 

Healthy riparian cover and minimal urban development are important for these communities. Since benthics are so small, and live in the stream for a period of their life they are a good indicator of local impairments to water quality as they each have different pollution thresholds. Some benthics can tolerate poor water quality, while some cannot. By using the presence and absence of the pollutant tolerant species, we can start to get an idea of stream health and apply that information to the entire watershed. Benthic invertebrate samples are collected through several sampling methodologies (e.g. Ontario Benthos Biomonitoring Network). The invertebrates are then sorted and individual specimens are identified to either the order/family/genus/species level. GRCA analysis uses a number of indices based on community composition and individual species traits.

Terrestrial Monitoring

Forests and natural areas are important habitats for people and wildlife. Non-native pests, and pathogens can have a negative impact on the natural area, by reducing native flora and reducing vital wildlife habitat. The GRCA conducts two types of invasive species monitoring to track and map the spread of priority nuisance species. A trail system inventory and a roadside monitoring program are completed for conservation areas and municipal road systems. The trail systems within the priority public lands will be walked in their entirety, inventorying suite of invasive plants. Both sides of the trail will be surveyed, making note of which side the invasive species are on. Along the trail system, if there is a population of invasive plants, GPS points are taken as well as the quantity and distribution are recorded. This information helps us to monitor the growth of a population and help to prioritize and target areas in need of restoration.

 

Roadside monitoring has been completed in the GRCA jurisdiction since 2015. Each municipality on a three year rotating schedule is monitored for invasive species along the roadsides. This is completed by driving along roads and identifying invasive species. This inventory does not include the urban areas, such as subdivisions since most of the areas are mown lawn with low presence of invasive species. Similarly to the trail monitoring populations of invasive species are marked and their quantity and distribution is recorded. By conducting roadside surveys it helps to determine the spread of invasive species across municipal boundaries and helps with early detection of new invasive species.