Watershed Strategy

Key Natural Resource Issues in Conservation Halton’s Watersheds

Conservation Halton has identified 13 key natural resource issues and risks that will be addressed in our 2024 Watershed-Based Resource Management Strategy (“Watershed Strategy”). These issues and risks were identified in the context of climate change and based on a review of environmental monitoring data, technical reports/studies, a public survey, and the expertise of Conservation Halton’s staff.

Summary of Key Issues

Public Survey Results

Background Information

This section explains the causes of natural resource issues in Conservation Halton’s watersheds.

Water is vital. It supports all life on earth and connects natural features, plants, animals, and human beings that rely on it. Precipitation, evaporation, condensation, melting, and freezing are important parts of a continuous cycle. Within our local watersheds, some precipitation infiltrates into the ground. Some of it flows along the surface of the land and enters creeks, wetlands, and the lake as runoff. Water evaporates from the plants, animals, land, and waterbodies, helped by the sun. Evaporated air, as moisture, is carried up into the atmosphere; it condenses to form clouds, then falls once again back to earth as precipitation. It continually moves in an integrated system called the hydrologic cycle, also known as the water cycle. Understanding the connections and influences of natural processes and human activities on the water cycle is critical to identifying and managing natural resource issues.

The water cycle has natural variability (e.g., periods of droughts and floods). However, human activities have led to profound changes in the water cycle. Converting land from its natural state, such as cropping or urbanization changes the way water moves over the landscape. Hardened surfaces such as concrete and pavement reduce the ability of the land to infiltrate water into the soil, increasing and accelerating contaminated surface runoff. Dams, weirs, channels, and other structures alter the flow and direction of water through a watershed. Taking water from surface and groundwater sources can also alter its natural pathways, reduce downstream flow, deplete groundwater levels, and influence water availability to springs and wetlands. Human activities — particularly the burning of fossil fuels, land clearing and urbanization — are increasing the concentrations of greenhouse gases in the atmosphere and warming the planet. Rising temperatures cause the rates of evaporation and precipitation to intensify.

A changing water cycle increases the frequency and intensity of natural hazards such as drought, extreme heat and precipitation events globally and in Conservation Halton’s watersheds. Simply put, our future climate will be warmer, wetter and wilder. We are already experiencing an increase in the frequency and severity of localized weather events, such as heat waves, heavy rainfall, ice storms, and heavy winds. These extreme weather events affect biodiversity and pose risks to human health, safety, and property.

Summary of Key Natural Resource Issues

Conservation Halton has identified 13 key watershed-scale natural resource issues and risks specific to our watersheds. Other natural resource issues in our watersheds are more localized, but no less important to address. These issues include dynamic beaches, shoreline erosion, shoreline flooding, surface/overland erosion, unstable bedrock (e.g., karst), and unstable soils.

Description: Flooding occurs when water overtops the banks of creeks and flows onto adjacent lands. Flooding results from intense rainfall over short periods of time, long periods of rainfall, heavy snow melt, or channel constrictions such as ice jams, debris, or undersized infrastructure. Other factors can worsen flood risk including the loss or degradation of natural features such as wetlands, increased impermeability of soils due to urbanization, illegal dumping of fill in creek valleys, physical alterations to creek banks which may cause waters to spill beyond the natural floodplain, and climate change.

Conservation Halton maps flood hazards according to provincial standards.

HISTORIC FLOODING

VULNERABLE AREAS

KEY IMPACTS

2014, Burlington (centred over Roseland & Tuck Creeks)
2000, Oakville (Fourteen Mile Creek)
1980, 2009, 2022, Lowville (Bronte Creek)
1954, Hurricane Hazel (watershed-wide)
1950, Town of Milton (Sixteen Mile Creek)

Southeast Oakville: Morrison-Wedgewood Diversion Channel Spills, Lower Wedgewood, Lower Morrison & Joshua’s Creeks
Southwest Oakville: Sheldon Creek Spill to Bronte Creek, Fourteen Mile & McCraney Creeks
Southeast Burlington: Tuck, Shoreacres, Appleby & Sheldon Creeks
Southwest Burlington: Grindstone, Falcon & Roseland Creeks, & Hager-Rambo Creek & Diversion Channel System
Urban Milton: Sixteen Mile Creek
Lowville, Carlisle, Progreston & Cedar Spring Community: Bronte Creek
Millgrove & Hidden Valley Community: Grindstone Creek
Highway 6 Corridor, Flamborough: Grindstone Creek, including spill from Bronte Creek

Risk to life & property
Risk of slope failure & erosion (e.g., bank & overload)
Degraded water quality (e.g., increase in sedimentation, nutrients, etc.)
Degraded &/or loss of habitat
Damage to farmland

SOCIO-ECONOMIC:

Cost of maintenance, repair, & replacement
Cost & availability of insurance
Cost of & accessibility to emergency services
Short response time to high intensity storms
Infrastructure damage, repair

Description: Drought occurs when there is a water shortage. It results from a period of persistent drier-than-normal conditions with below normal precipitation and high temperatures. Other factors that can worsen drought include the loss and fragmentation of forests and wetlands, an increase in the use of surface and groundwater, and climate change.

Conservation Halton monitors drought through our Low Water Response Program.

HISTORIC DROUGHTS

VULNERABLE AREAS

KEY IMPACTS

2022
2016
2012
2007
1998-1999

Tributaries that flow through fine till plains (e.g., tributaries of Indian, Lowville, Mount Nemo, & lower Bronte Creek)
Urban creeks including upper reaches of Roseland, Rambo & Creeks, east branch of Hager Creek, Falcon Creek upstream of Hwy 403, LaSalle Creek, & upper reaches of Wedgewood & Joshua’s Creeks in Oakville
Grindstone Creek tributaries either near their upstream end, along their entire length or between their point of origin & outlet
Tributaries north-west of Scotch Block reservoir, primarily in the northern reaches of Sixteen Mile Creek
Areas with private shallow wells
Areas above the Niagara Escarpment where groundwater aquifers are typically shallow

Surface & groundwater supply shortages (e.g., shallow wells & creek water levels decrease or dry up)
Degraded water quality (e.g., increase in creek temperatures, concentration of contaminants & nutrients)
Degraded &/or loss of habitat
Release of carbon (e.g., from wetland soils)

SOCIO-ECONOMIC:

Crop stress &/or failure & associated costs
Lack of sufficient water for irrigation & domestic supply
Cost of importing water

Description: Valley erosion occurs when there is an excessive loss of soil due to natural creek processes. Valley erosion results from periodic increases in peak creek flow, changes in channel form, unstable and steep slopes, loss of riparian vegetation (a strip of vegetation along the edge of a creek or waterbody), sediment load levels, ice jams or soil type. This can cause bank slumping, scouring, undercutting, and ultimately slope failure. Other factors can worsen valley erosion including vegetation removal, construction activities in proximity to the slope (e.g., illegal dumping or excavation of fill in creek valleys, soil compaction, inadequate drainage, and new structures), poorly maintained infrastructure such as culverts and bridges, and climate change.

Conservation Halton maps valley erosion hazards according to provincial standards.

VULNERABLE AREAS

KEY IMPACTS

Areas with steep exposed slopes (e.g., North Oakville, Sixteen Mile Creek), &/or clay/shale & sand/gravel soils (e.g., Hidden Valley, Burlington, Grindstone Creek)
Areas exposed to intense periods of high creek flow (e.g., downstream reach of Indian Creek below Hager-Rambo Diversion Channel, Burlington, North Shore; Sixteen Mile Creek downstream of concrete channel in downtown Milton; & small western tributaries of Grindstone Creek south of Highway 5)

Risk to life & property due to instability & slope failure
Loss of land
Degraded water quality due to increased suspended sediments & contaminants
Accumulation of contaminated sediment & debris in creeks, especially behind dams, weirs & at the mouths of creeks
Changes in channel form (e.g., creek deepens &/or widens creating barriers for aquatic species, thermal pollution, further land loss)
Degraded &/or loss of habitat

SOCIO-ECONOMIC:

Infrastructure exposure due to undercutting & scouring
Costs for repair, realignment or replacement

Description: Chloride is released through natural processes such as bedrock weathering and precipitation. There have been significant increases in chloride concentrations in surface water over the last 50 years throughout the watershed. At least one sample taken from most monitoring sites over a recent five-year period exceeds the provincial guideline (e.g., Fourteen Mile Creek at Lakeshore Rd, Oakville; Sixteen Mile Creek Main Branch at Speers Rd; and Sheldon Creek at Shell Park, Oakville). Other factors can increase chloride concentrations including use of road salt and water softening salt, degraded and/or loss of natural features that filter water, stormwater management ponds, and wastewater treatment plant effluent.

Conservation Halton monitors chloride concentrations in surface water and ground water as part of the Provincial Water Quality Monitoring Network, and through our surface and groundwater water quality monitoring programs.

VULNERABLE AREAS

KEY IMPACTS

Creeks downstream of or in urban areas, especially creek mouths (e.g., Indian Creek, tributary of Bronte Creek; West and East Branches, Sixteen Mile Creek; & Fourteen Mile Creek at Lakeshore Rd)

Degraded surface water quality resulting in increased toxicity to fish and other aquatic life
Degraded habitat (e.g., harms vegetation & can change the plant community structure)

SOCIO-ECONOMIC:

Increased rates of corrosion of infrastructure
Increased cost to repair infrastructure

Description: Suspended solids are materials such as silt, clay, plankton, and microscopic organisms that remain suspended in the water column. They typically carry pollutants and nutrients. Concentrations are variable throughout the watersheds depending on weather conditions (e.g., high during storm events and low during dry periods) and are influenced by erosion and the decomposition rate of organic materials. Other factors can increase suspended solids concentrations including loss of riparian vegetation, runoff from urban and agricultural areas, illegal dumping of fill in creek valleys, wastewater treatment plant effluent, and climate change.

Conservation Halton monitors suspended solids concentrations in surface water as part of the Provincial Water Quality Monitoring Network and through our surface water quality monitoring program.

VULNERABLE AREAS

KEY IMPACTS

Creeks downstream of or in urban and agricultural areas (e.g., East Branch, Sixteen Mile Creek; Main Branch, Bronte Creek)
Creek mouths flowing into Lake Ontario (e.g., Fourteen Mile, Sixteen Mile, Bronte, Grindstone Creeks)

Degraded water quality due to reduced light penetration, thermal changes, increased nutrients, sediment plumes
Degraded aquatic habitat
Damaged fish gills

SOCIO-ECONOMIC:

Higher water treatment costs
Reduced creek aesthetics

Description: Sedimentation occurs when solid particles settle out of suspension to the creek or pond bottom. Factors that increase sedimentation include runoff from poorly managed fields and construction sites with inadequate erosion and sediment controls, illegal dumping of fill in creek valleys, dams, weirs, and climate change.

VULNERABLE AREAS

KEY IMPACTS

Some stormwater management ponds, numerous online ponds & dug out channels, behind dams and weirs throughout the watersheds
Bronte and Hamilton Harbours

Increased flood risk resulting from reduced capacity of the creek system to carry high flows
Weir/dam breach or failure & release of contaminants causing aquatic habitat damage
Degraded water quality (e.g., increased nutrients & contaminants)
Physical alteration of creeks and the near shore (e.g., decreased water depth or narrowing of creeks, decreased flood storage, formation of barriers to aquatic species, thermal pollution)
Smothered aquatic habitat

SOCIO-ECONOMIC:

Cost of repeated dredging of harbours, online ponds, & stormwater management ponds
Disposal of dredged material
Infrastructure damage and repair

Description: Phosphorus is a nutrient released into the environment naturally through bedrock weathering and erosion processes. It binds to suspended sediment and causes increased plant growth, including algae. Total phosphorus is a measure of all phosphorus, whether dissolved or particulate. Average annual concentrations have exceeded the provincial guideline at almost all the watershed monitoring sites at least one year over a recent five-year period (e.g., Fourteen Mile Creek at Lakeshore Rd; Bronte Creek upstream of Mountsberg Reservoir and Grindstone Creek at Hamilton Harbour). Concentrations are influenced by erosion and soil type. Other factors that can increase concentrations include fertilizer application, runoff from poorly managed fields, increased impermeability of soils in urban areas that increase stormwater runoff, loss of riparian vegetation that filter and store nutrients, municipal wastewater, and climate change.

Conservation Halton monitors total phosphorus concentrations as part of the Provincial Water Quality Monitoring Network and through our surface water quality monitoring program.

VULNERABLE AREAS

KEY IMPACTS

Creeks downstream of or in urban &/or agricultural areas (e.g., Indian Creek & Main Branch, Bronte Creek above the Niagara Escarpment; West & East Branches, Sixteen Mile Creek)
Creek mouths flowing into Lake Ontario (e.g., Fourteen Mile, Sixteen Mile, Bronte, Grindstone, Hamilton Harbour)

Increased growth in nuisance & harmful algal blooms
Risk to human health & wildlife (e.g., toxins released by algal blooms)
Degraded water quality
Degraded/loss of aquatic habitat & species (e.g., lowered dissolved oxygen stresses fish & aquatic life)
Near shore recreational opportunities adversely affected by toxic & nuisance algae

SOCIO-ECONOMIC:

Increased costs to upgrade wastewater treatment plants
Costs to remove/clean-up algae
Healthcare costs for humans & pets
Adversely affected aesthetics (e.g., look & smell)

Description: Thermal pollution occurs when surface water temperatures increase. Widespread increases in surface water temperatures have been recorded in central and downstream reaches across the watershed over the last 20 years. Surface water temperature is influenced by yearly and seasonal weather (e.g., wet versus dry, air temperature, etc.), sun exposure, creek channel form, groundwater discharge, and erosion (e.g., wider, shallower creeks with more surface area). Other factors can increase surface water temperature including increased impermeable surfaces and reduced natural shade in urban areas, loss of forests and riparian vegetation, use of dams and on-line ponds which increase surface exposure to sunlight, surface water takings which temporarily reduce water depth, and climate change.

Conservation Halton monitors surface water temperatures through our surface water quality monitoring program.

VULNERABLE AREAS	KEY IMPACTS
Central and downstream reaches of creeks that are not fed by cooler groundwater discharges & springs Urbanized creeks (e.g., creeks that receive warmer runoff from stormwater management ponds & overland runoff) Creeks with limited to no riparian vegetation or with additional human impacts (e.g., on-line ponds) Creeks with intermittent water flow that typically become warmer before drying up	Degraded water quality (e.g., increased water temperature causes lower dissolved oxygen levels & helps release nutrients from soil Degraded/loss of aquatic habitat Potential loss of aquatic species sensitive to warmer water temperatures (e.g., brook trout)

Description: Groundwater is the water that infiltrates the soil, is stored, and moves underground. Private and municipal groundwater wells serve approximately 12% of Conservation Halton’s watershed population. The number of municipal drinking water system users is increasing. Groundwater quantity is influenced by the size of aquifers which are bodies of rock and/or sediment that hold groundwater, the ability of the materials in the ground to transmit water, and the loss and gain of water (water balance). Other factors can decrease groundwater quantity, including increased groundwater demand and excessive pumping, increased impermeability of soils due to urbanization, and climate change.

Conservation Halton monitors groundwater quantity through the Provincial Groundwater Monitoring Program and at selected wetland locations.

VULNERABLE AREAS

KEY IMPACTS

Subwatersheds that are stressed based on monthly &/or annual groundwater demand (e.g., Upper West Branch, Sixteen Mile Creek & Willoughby Creek (Bronte Creek))
Areas with shallow aquifers (e.g., some locations below the Niagara Escarpment where overlying shale is close to or at the surface
Areas where soil permeability is reduced due to land use change

Depleted groundwater sources due to over extraction
Reduced discharge rates that supply base flow and cold-water inputs to surface water features such as creeks & wetlands
Reduced survival & reproduction of aquatic species, including fish that rely on cool or cold-water habitats
Land subsidence (e.g., loss of support below ground due to the removal of water)
Risk to drinking water supplies where there is reliance on groundwater

SOCIO-ECONOMIC:

Dry or unusable shallow wells
Increased cost to drill a deeper well
Increased cost to pump water from a lower water table

Description: Groundwater quality is the physical, chemical, biological, and radiological characteristics of water under the earth’s surface. Water quality is described by measuring key characteristics or indicators such as chloride, sodium, nitrate, sulphate, arsenic, iron, lead, and manganese. Groundwater quality varies across the watersheds but is generally of good quality. However, some areas show trends of increasing chloride and sodium concentrations in well supplies. Groundwater quality is influenced by the permeability and chemical properties of the rocks and sediments through which it moves, the depth from ground surface, and natural climatic variations (e.g., rainfall and evaporation rates). Other factors can worsen water quality including the use of road salt and water softening salt, application of fertilizers, runoff from poorly managed fields, septic system effluent, and climate change.

Conservation Halton monitors groundwater quality indicators as part of the Provincial Groundwater Monitoring Network and through our groundwater quality monitoring programs.

VULNERABLE AREAS

KEY IMPACTS

Sizeable areas above the Niagara Escarpment, two large areas along the Lake Ontario shoreline in Burlington & Oakville, one large area near Ashgrove where contaminants above the ground surface infiltrate into shallow aquifers where the water table is shallow & surface materials are permeable
Significant areas above the Niagara Escarpment where permeable soils or fractured bedrock at surface facilitate increased recharge; recharge water can contain dissolved contaminants from runoff
Clusters of unused, improperly abandoned wells identified in the Campbellville area, resulting in preferential pathways for contaminants to enter groundwater
Unidentified potential clusters of unused wells may exist in other areas that have not yet been studied, resulting in preferential pathways for contaminants to enter groundwater
Some urbanized areas where trends show increasing chloride and sodium concentrations

Degraded groundwater drinking water sources
Reduced availability of potable groundwater due to contamination
Degraded surface water quality due to contaminated groundwater discharging into creeks & wetlands
Degraded creek & wetland habitats leading to increased toxicity and degraded habitats for flora & fauna
Degraded soil & land quality (e.g., increased soil salinity)

SOCIO-ECONOMIC:

Increased costs to treat drinking water sources
Risk to human health
Healthcare costs for humans & pets

Description: Natural features include forests, wetlands, valleys, and water courses. They provide benefits and services such as flood attenuation, erosion control, carbon storage, filtration of contaminants, wildlife habitat, recreation, and more. In Conservations Halton’s watersheds, over 70% of wetlands have been lost or fragmented; remaining wetlands are located primarily in the upper watershed reaches. Riparian habitat coverage is variable but poor overall, especially in highly urbanized areas. Forest cover is poor overall. Large tracts of forest are rare (mostly above the Niagara Escarpment) and urban forests are small. Degradation, fragmentation, and loss of natural features are influenced by yearly and seasonal weather patterns, natural hazards (e.g., erosion, flooding, and drought), and disease. Other factors can worsen degradation and loss including the removal of natural features and wildlife corridors, urban encroachment, invasive species (e.g., Emerald Ash Borer), linear infrastructure (e.g., roads, utilities, etc.), and climate change.

Conservation Halton monitors biodiversity and ecological health through our Long-Term Ecological Monitoring Program (LEMP). Trends are monitored through our Ecological Land Classification (ELC) and Natural Areas Inventories.

VULNERABLE AREAS

KEY IMPACTS

Urban areas below the Niagara Escarpment
Areas sensitive to human disturbance (e.g., Waterdown Woods, Hamilton, home to the Jefferson Salamander & Fourteen Mile Creek, home to the Redside Dace (fish))
Rural areas above the Niagara Escarpment in central & eastern Grindstone Creek watershed

Increased natural hazard risk
Reduced resiliency to impacts of climate change
Degraded water quality (e.g., increased suspended solids, nutrients & contaminants)
Increased habitat fragmentation causing further degradation (e.g., limits species movement & spread to new locations)
Loss of biodiversity due to lack of suitable habitat & increased disturbance

SOCIO-ECONOMIC:

Loss of access to nature
Risk to mental health
Loss of Indigenous peoples’ cultural, spiritual, & medicinal practices
Loss of outdoor recreational opportunities
Increased cost of remedial/engineered measures to compensate for loss or damage to natural features

Description: Invasive species (e.g., Emerald Ash Borer and Garlic Mustard) are organisms that are not native to an area, adapt easily, reproduce quickly, and have a broader tolerance for a range of environmental conditions than native species. Natural features across Conservation Halton’s watershed, such as forests and wetlands, are negatively affected by invasive species. They are spread naturally by vectors such as wind, animals, insects and birds, and extreme weather events (e.g., hurricanes and flooding). Other factors can increase the spread including human activity (e.g., deliberate or accidental introduction of invasive species such as zebra mussels, goldfish, and purple loosestrife), and climate change.

Conservation Halton monitors the existence, spread and impact of invasive species.

VULNERABLE AREAS

KEY IMPACTS

Natural areas used for human activity (e.g., trail users bringing invasives into interior habitats & spread through fishing, boating, etc.)
Natural areas adjacent to urban or agricultural areas
Creeks that empty into Lake Ontario
Ditches & natural areas adjacent to roads (e.g., invasive species spread through ditch maintenance)

Degraded or fragmented habitat & decreased biodiversity (e.g., invasive species often out-compete native species, become parasites & spread diseases)
Species loss or impairment; life cycles impacted
Impaired ecosystem functions (e.g., loss of natural benefits & services)

SOCIO-ECONOMIC:

Risk to human health (e.g., toxic sap of giant hogweed & wild parsnip)
Risk to property (e.g., damaged water pipes from zebra mussels)
Reduced crop production & foraging space
Adversely affected recreation & aesthetics
Reduced property values
Increased land management, removal, & operational costs

Description: Biodiversity loss is the decrease or disappearance of species. The status, health, and range of many species is shifting in Conservation Halton’s watersheds (e.g., decline of some tree species due to pests/pathogens). Biodiversity loss is influenced by yearly and seasonal weather patterns, natural hazards (e.g., erosion, flooding, and drought), and disease. Other factors that worsen biodiversity loss include loss of natural features and habitat, habitat degradation and fragmentation, spread of invasive species, and climate change.

Conservation Halton monitors biodiversity through our Long-Term Ecological Monitoring Program (LEMP) and Natural Areas Inventories.

VULNERABLE AREAS

KEY IMPACTS

Natural areas fragmented by adjacent urban or agricultural areas (e.g., Bronte-Burloak Woods, Town of Oakville)
Natural areas sensitive to human use (e.g., Waterdown Woods, Hamilton)
Areas with species that have highly specialized requirements (e.g., Redside Dace, Fourteen Mile Creek)

Impaired ecosystem functions (e.g., loss of natural benefits & services)
Reduced resiliency to impacts of climate change
Species loss, impairment or shifts in range

SOCIO-ECONOMIC:

Risk to life & property (e.g., aggravation of natural hazards)
Increased management & operational costs for remedial measures & infrastructure
Reduced crop production & foraging space due to decline in pollinators
Loss of Indigenous peoples’ cultural, spiritual, & medicinal practices
Adversely affected recreation & aesthetics

Public Survey Results

A public consultation period from October 27 to December 8, 2023 engaged local municipalities, members of the public, and others who live and work within Conservation Halton’s watersheds to share their insights and opinions about key natural resource issues in our jurisdiction.

The 159 survey submissions confirm that our proposed key issues reflect local concerns and priorities. Responses provided further examples of where key issues are a concern and identified groundwater quality as a missing key issue. Public feedback has been incorporated into the Summary of Key Natural Resource Issues.

Survey participants identified the following issues as the most important:

Degradation, Fragmentation & Loss of Natural Features
Groundwater Quality
Biodiversity Loss
Riverine Flooding
Invasive Species

Groundwater Quality has been added to our summary of key issues. Other identified concerns (e.g., air quality, protection of archeological sites, noise pollution) are beyond the scope of the Watershed Strategy because they are within the mandate of other groups and agencies.

Survey participants identified five watershed monitoring priorities:

To coordinate monitoring efforts with municipalities and others to avoid duplication
To focus on identifying trends based on good data, and to share data and information regularly
To identify and fill data gaps with a focus on understanding the key watershed-scale natural resource issues
To identify natural assets on a watershed basis, and
To collect and assess data to inform management actions and outcomes (adaptive management)

Survey participants agreed that Conservation Halton should continue to build partnerships and recommended that partnerships focus on:

Coordinating activities, particularly with respect to climate change initiatives
Exploring opportunities for additional program funding and in-kind support
Hosting a shared repository of monitoring data, natural heritage information and restoration opportunities
Undertaking Lake Ontario shoreline monitoring and management
Promoting volunteer opportunities (e.g., citizen science/community explorers)
Fostering and facilitating landowner stewardship activities

Several survey participants recommended that Conservation Halton take a lead role, among partners, in assessing the impacts of climate change on local natural resources and determining their value as natural assets at the watershed scale.