What are Streams and Rivers?
Streams and rivers can be likened to the arteries in the human body, in terms of importance and function; they perform the crucial services of nourishing and flushing wastes from the landscape. Complex interactions between the water, soil, microorganisms, plants and animals create living networks that join the water with the land. These ecosystems are as much a part of streams as the flowing water itself.
The life-giving properties of streams and rivers have been celebrated by people throughout the ages. The power of flowing water has been animated and symbolized in religion, myth and stories. Today, as in the past, people live near streams and rivers in villages and large cities, and rely on them for transportation, food, recreation and waste disposal. The problem we are faced with today is that human populations and technologies can seriously interfere with the ability of streams and rivers to provide these important ecosystem services.
To understand how streams and rivers can be damaged, we first need to know how they function. The complexity of riverine ecosystems makes this task a continually evolving one, as new theories and understanding emerge. Different types of streams have different qualities, depending on variables such as water volume, surrounding topography and location in the watershed.
The physical components of streams include:
- The watershed, which contains the stream as well as the surrounding land area that drains into it
- The river valley, which may have been formed by the river itself or previous events such as glaciation or tectonic activity
- The riparian zone,the land area adjacent to a water body that is composed of saturated soils, water-loving vegetation and the associated ecosystems
- The floodplain, the land immediately adjacent to a stream that is covered in water in relatively frequent (i.e. seasonal or interannual) events
- The stream channel, which is shaped by the stream and influenced by factors such as the amount and timing of water flows, the surrounding vegetation (or lack thereof), sediment load and human land use
- Other connected land areas, such as forest and meadows, and water bodies including lakes, wetlands, and marine areas
Where are streams and rivers found in the CRD? Major streams and rivers in the Capital Regional District and their watersheds
The CRD has several large river systems, as well as dozens of smaller streams and creeks. In all there are over 300 watersheds within the region. Some of the major rivers are:
- San Juan River which flows into the ocean at Port Renfrew.
- Sooke River, whose watershed forms part of the region’s drinking watershed, flows through the Sooke Pot Holes, and out into Sooke Harbour.
- Jordan River, where a large sand/gravel bar provides a popular surfing beach.
- Goldstream River which supports an annual run of chum and coho salmon, and flows into the head of Saanich Inlet.
Major streams in the core urban area include:
- Colwood Creek which empties into Esquimalt Lagoon through the Royal Colwood Golf Course and Royal Roads University
- Millstream Creek which flows into Esquimalt Harbour
- Colquitz River which flows out of Elk/Beaver Lake and into Portage Inlet
- Craigflower Creek which flows from Thetis Lake
- Bowker Creek which flows from the University of Victoria and out into the ocean at Oak Bay
- Douglas Creek, which flows through Mt Douglas Park and out into Haro Strait
Streams in the rural area of Saanich Peninsula include:
- Tod Creek, flowing into Saanich Inlet near Brentwood Bay
- Hagan Creek, which flows through farmlands in Central Saanich and into Saanich Inlet
Why are streams and rivers important?
Streams provide many ecological services for people and wildlife. Some of these include:
- Critical habitat for many species, including Pacific salmon, trout and other fish, amphibians, birds, mammals and invertebrates including insects.
- Nutrient cycling, i.e. providing sources, transportation and sinks for nutrients and organic material in the watershed
- Transportation of sediment, from high elevations ultimately to the ocean. Through this process, streams reshape the land through erosion in some areas and deposition of sediment in others, such as deltas and estuaries. However, when this process is accelerated by human activities, too much erosion and sedimentation can damage downstream ecosystems and landscapes.
- Mediating water flows, i.e. capturing runoff from the land and directing it downhill to fresh water bodies and the ocean. The volume and timing of water flows are vital to the proper function of aquatic and riparian ecosystems. Extreme events such as floods and droughts can also have major impacts on ecosystems and human welfare.
What kind of wildlife uses streams and rivers?
Many wildlife species, including birds, mammals and many fish and other aquatic species have a requirement for freshwater habitat for at least part of their life cycles. The continued existence of these populations, especially in urbanized areas, is dependent on stream water quality and healthy vegetated riparian areas
. Species such as Pacific salmon
are critically dependent on streams and rivers to complete their life cycle. Some species, such as coho, spend a year or more in streams systems before heading out into the ocean as adults. Others salmonids such as resident cutthroat trout
spend their entire lives in freshwater systems.
Many bird species spend time foraging along streams and rivers, for example bald eagle and the great blue heron
. Mammals such as otters, raccoons, bears and beavers use streams and rivers for foraging and denning and as transportation corridors.
Why are streams and rivers important?
As the arteries of the landscape, streams and rivers are essential to the proper functioning of many other related ecosystems. Some of the many important functions that streams perform for people include:
- Drinking water source
- Source of hydro-electricity
- Food source
- Flood regulation
What threatens streams and rivers? Urbanization:
The major threat to rivers and streams in this region is urbanization, including contaminated run-off that enters waterways from roads, roofs and other impervious surfaces. As precipitation flows over these surfaces, contaminants are picked up and transported directly into streams via storm drains. A high percentage of impervious surfaces in a watershed can lead to “flashiness” in creek flow. Sudden intensity in stream flow can cause increased rates of stream bank erosion. Development can cause sediments to enter a stream, which increases turbidity and can harm fish and other aquatic species in the stream. The impacts of urbanization on streams may be intensified by climate change, as the severity and intensity of winter storm events are predicted to increase in this region, along with prolonged drought periods during the summer. Channelization:
Ditching and straightening of streams to facilitate drainage of lands for agriculture and other purposes can also threaten stream health. When streams are diverted underground into pipes, the natural filtering and cleansing abilities of water percolating through soil is compromised. This practice also increases the possibility of flooding and erosion along a stream. Failing septic systems
near streams can compromise water quality in streams. It is important to pump out septic tanks regularly and ensure that drainage fields are functioning properly. Dams and weirs
built on a stream alter flow dynamics, and can precipitate loss of habitat and species in a stream ecosystem.
How can I help?
There are several conservation groups in the region that work hard to preserve and restore streams and rivers. Join a group near where you live and learn more about your own watershed. Click here
to find out more about what you can do to help preserve stream and river health.
Additional Links and Resources © Top image courtesy of Evan Leeson