Urban Creek Challenges


There are many challenges facing a modern urban creek watershed. Some major issues include:

  • Habitat reduction and land use
  • Contamination and encroachment
  • Invasive species
  • Habitat Reduction and Land Use
Habitat Size Matters!

One of the biggest challenges facing the habitats of urban creeks is their size. Urban creeks are often surrounded tightly on all sides by human development – that is to say, our houses, workplaces, recreation spaces and roads. This means that creek habitats are thin and often fragmented by roads and culverts. Some species of animals and plants need large, bulky blocks of habitat. Some species dislike edges and live only in “forest interior,” the kind of habitat that has to be about 100+ metres away from any forest edges. Many also dislike human disturbance, and are uncomfortable within 100 m of human interference zones (including trails).

AcadianFlycatcher_Copyright Queens Printer for Ontario_OptionBThe Acadian Flycatcher (Empidonax virescens), for example, is an Endangered bird species in Ontario that loves to nest in mature, forested ravine systems full of Sugar Maple, American Beech and Eastern Hemlock trees, with a stream system flowing below. Fourteen Mile Creek’s habitat features could work for this species. However, the Acadian Flycatcher is also an area-sensitive species, needing large, continuous forest tracts to breed in. These birds prefer forests over 40 hectares in size, but even that is inadequate for many. Over half of Ontario breeding sites for the Acadian Flycatcher are found within more than 100 ha of forest. Not even Fourteen Mile Creek’s best natural spaces can be called ideal for Acadian Flycatcher use.
Unfortunately, built-up creeks such as Fourteen Mile Creek rarely get the chance to re-expand their natural ecosystems. Far more often, the opposite occurs: nearby green spaces like farmland are intensified with more human use, rather than naturalized. Once a green space is built-over – very often after removing the fertile topsoil – it becomes very expensive, difficult, and time-consuming to re-naturalize. Habitat is reduced and fragmented to smaller and comparatively sterile gardens, yards and parks.

constructionCurrent Example: Merton Lands – Saw Whet Golf Course and Deerfield Golf Course

The Merton Lands can be found directly north of the intersection of Bronte Road and the Queen Elizabeth Way/403, making up the bulk of the property between these roads and Fourteen Mile Creek. The majority of the land is currently divided between the privately-owned Saw Whet Golf Course, and the Deerfield Golf Course which is owned by Infrastructure Ontario. Together, these two properties account for nearly 100 hectares of relatively undeveloped land, which together with a few other small parcels, represent an enormous amount of land with an uncertain future.

In March of 2013, the Town of Oakville initiated a study of the undeveloped Merton Lands for potential future development. Many technical reports were made and many public consultations were carried out. Initial concept drafts saw heavy development of the majority of undeveloped land, but concerns over watershed hydrology, natural heritage integrity and loss of public green space caused many residents to speak out in concern over the project. Given that the Merton Lands lie adjacent to the Fourteen Mile Creek Valley Environmentally Sensitive Area (ESA), such environmental concerns were certainly worth examining critically. In the heavily urbanized modern Oakville, which has seen rampant development in only decades, few remaining green spaces south of Dundas St. can match the size of this space.

Amid an active and animated debate and discussion process which still has yet to see resolution on the issue, Infrastructure Ontario decided to withdraw its development application, while the privately-owned Saw Whet lands development issue has been brought before the Ontario Municipal Board (OMB) in an appeal, where a decision has yet to be reached.


What would changes in zoning, land use and subsequent development of the Merton Lands mean for Fourteen Mile Creek?

What could forward-thinking ecological planning do to support its watershed?

The Halton Natural Areas Inventory (2006), a project which reviewed many tracts of land within the Halton region, recognized the significance of the Fourteen Mile Creek Valley ESA. Among the recommendations of this document included the expansion of this important region in order to better protect its rich natural heritage. The Merton Lands exist entirely within the Fourteen Mile Creek watershed, and are directly adjacent to the Fourteen Mile Creek Valley ESA. With such a rare opportunity to build on habitat so close to urban and suburban regions, tremendous natural gains could be made:

Wider Buffers
In watershed planning, a buffer is a thick natural border that protects delicate internal ecosystems from harsh outside        conditions, especially those caused by humans. Buffers absorb storm surges, filter water, reduce wind speeds and  temperatures, and broaden interior habitat spaces by pushing edges away from the middle of the habitat.WiderBuffers

Although sections of the Fourteen Mile Creek Valley on the north side of the creek have reasonable buffers, the forested border to the south is thin, optimizing human land use and restricting natural protections to the creek to minimal proportions.

Buffer expansion to expand the borders of the Fourteen Mile Creek Lands by planting native species and allowing natural regeneration would significantly improve stream and ecosystem health.

Bulkier Habitats
In ecology, a thin, spidery, fragmented habitat that twists and turns works only for species that love edges, and (as mentioned) does little to buffer water habitats. Bulky habitats with lots of protected interior space not only protect watercourses, but filter more air, store more carbon, reduce the ‘heat island’ effect, and provide habitat for uncommon interior species.

BulkyHabitatAlthough the north side of Fourteen Mile Creek Valley has more substantial bulk, the habitat on to the south is thin and fragmented.

Rounding out spidery and incomplete habitat borders by planting native species and allowing natural regeneration would significantly improve important habitat area.

More Connections and Wildlife Corridors to Other Natural Areas
Habitat connections and wildlife corridors are essential for both resident and migratory species. Over time, they also allow plants to move back and forth, allowing populations in one area to continue to mix and mingle with populations in another.MoreConnectivityAndWildlifeCorridors

The Fourteen Mile Creek Valley exists near some extremely substantial natural areas, including the Bronte Creek conservation lands to the west.

Creating significant habitat corridors between the two very large nature sanctuary regions by planting native species and allowing natural regeneration represents a monumental improvement in ecological integrity for both creek systems.

Removal of Invasive Species and Prevention of Planting Invasive Species
Property fringes formerly cleared and planted by humans are often breeding grounds for invasive plants like Common Buckthorn. If left to their own devices – especially in a regeneration setting – RemovalOfInvasiveSpeciesAndPreventionOfPlantingthey can easily explode and damage both new and existing habitat. Similarly, when a region is developed and new gardens, parks, and other landscaped settings are made, invasive species may be planted intentionally by horticulturalists because they are hardy and grow well on city property.

Fourteen Mile Creek is already fringed with many invasive species, and any restoration and landscaping work will likely encounter them.

Preventing invasive plants from being used in city plantings, removing existing invasive plants, and monitoring regeneration areas for invasive plants will protect ecosystem values in the current and future habitat zones.

Consideration for Landscape Values
Rarely do urban tracts of land include giant green spaces with uncertain futures. Having green spaces close to home is important for human well-being. With so much expansion occurring in Ontario, natural spaces are pushed further and further out of reach.

ConsiderationForLandscapeValuesPreventing the complete urbanization of nearby spaces ensures access to nature for citizens, now and into the future.




How can you help?
  • Be an active voice in the discussion. Make use of public information sessions and discussions. It is up to our communities to come together and decide what kind of place we want to see in the future!
  • Help local environmental groups and organizations by participating in planting events and invasive species removal!
Contamination, Encroachment and Disturbance

Fourteen Mile Creek, as with many urban creeks, suffers from a wide range of contamination issues:

fertilizerFertilizer and pesticide contamination from farmland, commercial, and residential properties

saltSalt and sedimentation from winter and sidewalk road maintenance.

chemicalsMiscellaneous chemical runoff from residential and commercial presence.

TreatedWastewaterTreated wastewater from water treatment plants is still high in nitrates, phosphates, and miscellaneous chemicals that can negatively impact stream water quality, and therefore aquatic ecosystems.

Untreated wastewater is occasionally flushed directly into many creeks in the greater Toronto and Hamilton area during the most extreme rain events each year. Storm surges overflow the wastewater containment facilities that don’t have adequate overflow tanks, leading to dumping untreated wastewater directly into the same streams and creeks these facilities normally protect.

spillsSpills, both accidental and intentional, dump contaminants directly into stormwater drains and streams. The effects of these spills can be devastating on the aquatic ecosystems, wiping out the most vulnerable species.

Encroachment is common in urban nature sanctuaries. This happens when adjacent residents and businesses push their yard boundaries out, or throw their garbage or yard waste into the nature sanctuary. Although typically minor for any one yard, across whole neighbourhoods, everybody’s actions add up very quickly, and damage the habitat values of the area. It is easy to cover up, damage and even remove plants, or introduce invasive weeds that could spread into the ravines.

Disturbance is a major challenge with urban nature sanctuaries. Sounds of city life and the constant presence of humans prevents some animals from living in urban habitats. Nature trails – while wonderful to have – also bring humans even further in to the habitats of animals and plants. Constant trampling can compact soils and crush plants, and skittish animals are forced to go further away to avoid humans. Off-trail hiking compounds these problems considerably, bringing disturbances deep into the heart of healthy habitats.

How can you help?
  • Avoid use of fertilizers and pesticides, and always follow product use regulations and guidelines. If at all possible – ditch the chemicals, garden naturally!
  • When applying salt to paths and driveways in the winter, try not to go overboard!
  • Avoid allowing chemicals, detergents, or other contaminants to flow freely off your property, and never pour harsh chemicals down storm drains!
  • Advocate for effective and adequately-prepared wastewater management systems in your local area.
  • Report any unusual spills that may come into contact with our creek systems!
Non-native Invasive Species

One of the biggest challenges facing natural areas in such heavily populated regions is non-native invasive species. These are plants, animals and fungi that originate from other parts of the world, but thrive in our climate and landscape so well that they multiply out-of-control and threaten our native species and ecosystems.

Fourteen Mile Creek is home to many invasive plants, which tend to be most prominent at the fringes of the nature sanctuary but many of which can be found throughout. Two examples of these include:

Garlic Mustard (Alliaria petiolata) is a common invasive ground cover with a garlic-like smell, frilly leaves and white flowers. It was originally introduced as a culinary herb.

1.GarlicMustardWhere Garlic Mustard establishes – typically in woodlands and forests – it can quickly form dense carpets that crowd out other native forest floor plants.

In Fourteen Mile Creek, Garlic Mustard is present especially at the disturbed forested habitat edges and fringes, but also finds its way (in varying degrees) into the main ravine habitats.




Common Buckthorn (Rhamnus cathartica) is one of Ontario’s most prominent invasive shrubs. Common Buckthorn is easily spread by birds like Robins and Cedar Waxwings, which feed on the berries and disperse them far and wide through their droppings.

2.CommonBuckthornOnce established, Common Buckthorn easily establishes dense thickets in fields, trailsides and forests alike, crowding out other vegetation.

In Fourteen Mile Creek, Common Buckthorn is especially common at forest edges, regenerating/reforesting thickets and trailsides, where it may form dense thickets of “miniature forest”, but may also cover the ground with seedlings. It may be found further into more established forested habitats, but is generally less abundant.

Fourteen Mile Creek is also home to invasive animals and fungi. Some examples of these include:

Dutch Elm Disease is a fatal tree disease caused by the non-native fungus Ophiostoma ulmi.

Elm trees become infected when bark beetles, carrying spores from the fungus in an infected tree, burrow under the bark of a healthy elm, thereby giving the fungus access to the tree’s inner tissues.

3.DutchElmDiseaseNo species of Elm native to Ontario is resistant to the disease. Once infected, the tree will eventually die off. Dutch Elm disease wiped out Elms across southern Ontario, with generally only younger trees – which have not yet been infected – persisting.

In Fourteen Mile Creek, Elm species such as White Elm (Ulmus americana) may still be found occasionally, growing as young trees. More frequently, however, dead and dying trees are spotted, losing bark and sometimes attempting to sprout from the trunk in hopes of staying alive.


Emerald Ash Borer (Agrilus planipennis) is a small, shiny, greenish Asian beetle that is currently destroying our populations of native Ash trees (Fraxinus sp.). The larvae of the beetle feed under the bark of Ash trees, and together with dozens of others larvae, cut off the flow of nutrients into the tree.

4.EmeraldAshBorerb_WithCaption TagEmerald Ash Borer is actively changing the shape of our forests as we speak, killing off mature Ash trees across our landscape.

In Fourteen Mile Creek, our Ash species are showing heavy signs of die-off. Countless street trees in many parks and neighborhoods have already been removed, or flagged for removal or insecticide treatment. In the ravines and trail systems, many White Ash (Fraxinus americana) and Green Ash (Fraxinus pennsylvanica) show canopy die-back, woodpecker damage, and epicormics growths (trunk sprouts), as the inevitable declines march forward.

How can you help?
  • Educate yourself on what plants are considered invasive. Visit http://www.ontarioinvasiveplants.ca/index.php/publications for an excellent list of resources.
  • Do not plant known aggressively invasive plants, especially if you live beside a nature sanctuary.
    *Under certain circumstances, if you live far enough from any nature sanctuaries, certain specific invasive plants may be acceptable for use. Consult with your local Conservation Authority to see if this option is advisable.
  • Never plant invasive plants that spread by roots/stems in a garden backing onto a nature sanctuary. Groundcovers like Periwinkle and Goutweed are particularly aggressive!
  • Do not transfer firewood between different areas. Invasive forest pests like Emerald Ash Borer are not abundant across the whole province, and you may unwittingly transfer them to new areas, causing local or even widespread damage.
  • Help local environmental groups and organizations (like Oakvillegreen) by participating in volunteer invasive species removal events!

Read more about Discover Your Creek Adventure at Fourteen Mile Creek

All photos and text provided by ecologist, David d’Entremont.