Did you know that 10,000 years ago or so, the Penticton area was under about 2 kilometers of ice? Even our mountain tops were covered. As the ice slowly melted over time, a proto-lake was formed, which flowed north toward the Thompson region. Gravel fans in our area are reminders of the run-off from that time of glaciation. Later, at some point the flow changed toward the south. The “benches” above the current valley bottom are the remains of beach levels. At one time, a large ice-dam in the McIntyre Bluffs area, towards what is now Oliver, burst, and the water rushed out of the valley, leaving behind Okanagan and Skaha Lakes, and the slow-moving Okanagan River and its surrounding wetlands and marsh. The slow river twisted its way through the wetlands, forming many ox-bow turns between the lakes.
The First Nations were content to live with the natural formations of this valley. When the first Europeans arrived in the Penticton area, they settled in the drier areas of the valley bottom. Small steamships pulled barges between the two lakes, carrying freight, and dredging kept the channel open to a sufficient depth. But as the town grew and more land was needed, and as folks experienced some years of severe flooding, it was decided in the 1940s to 1950s to “improve” the Penticton townsite between the rivers by putting a direct channel through from Okanagan to Skaha Lakes, thus cutting off the oxbows from river flow.
When the Penticton townsite was laid out, and the Penticton Band reservation lands, the border between the two ran down the center of the Okanagan River. When the channel was pushed through, this meant that some pieces of land on the west side of the channel belong to the city, while some pieces on the east side belong to the Penticton Band. Thus, the valley bottom involves both municipal and federal governments (and the Band government)–and the river itself is provincial! This means that when groups like the Friends of the Penticton Oxbows want to care for the oxbows, they must work with multiple levels of government, not to mention individual landowners, both in the City of Penticton and “locatee” landowners from the Band. But the Friends of the Oxbows are not daunted by this prospect, even if it does complicate things. Goals of the Friends include securing and managing habitat, encouraging natural riparian vegetation, providing controlled access (such as through “blinds”) for the public, preventing too much silt and other run-off materials from entering the oxbows, dredging out the excess that is already there, and improving water flow in and out of the oxbows.
Our tour started at the Okanagan Avenue northern access of the Warren Avenue oxbow. We saw turtles, ducks, redwing blackbirds, and many other birds. There is quite a bit of debris in the water, and an invasive species, yellow flag (a type of iris) has filled up a lot of the edges of the oxbow. Across the oxbow is locatee land; the family is working with a developer to put housing in the area, but as sustainably as possible to maintain the wetlands.
We also went to the Roy Avenue access point of the same oxbow, where we saw a large heron and mallard ducks. The deer enjoy browsing the native wild rose bushes, which also form a good natural riparian boundary area along the banks of the oxbows. The surrounding lands used to be productive bottom land during the freshet, which overflowed the natural banks and laid down nutrient-rich silt. The current higher banks are a result of the dredging done when the river was used for transport. The water weed here are a good sign of continuing productivity of this land.
Going on to the south end of this oxbow, on Warren Avenue, we saw the tall pole placed there for the osprey; this year a pair of geese decided to take over the nest, and the ospreys did their best to chase them away! There was once a crossing here for cattle as well. We were impressed with the size of the carp in this oxbow. The water this year is very low due to the lack of moisture over the winter, but there is still some surcharge from groundwater. Pipes connect most of the oxbows to the channel; however, they are placed so that overflow from the oxbows will go into the channel, but fresh water from the channel cannot get into the oxbows. The Friends of the Oxbows would like to see this remedied.
Next, we went to the oxbow access point at the foot of Kenney Avenue. There is one oxbow right there; and if one walks or drives down the dirt road, there is access to more oxbows. The first of these is behind Ayres Crescent. It has a lot of cat-tails growing in it, which is causing diminished productivity for birds that need open water; the very invasive yellow iris add to the problem as well. Tall cottonwood trees along the oxbow are typical of local riparian vegetation; there used to be many more of them in the area. Trees near the oxbows have been wrapped in fencing wire to discourage beaver from cutting them down. Along the highway by these oxbows are many Russian olive trees (they are not native to the area). If you decide to follow the path along these oxbows, be sure to watch out for snakes. Unfortunately, some folks also seem to think the land alongside the oxbows is a great place to toss their junk–cleaning these areas is another goal of the Friends of the Oxbows.
The oxbow at the foot of Brandon Avenue has been the receiving environment for half the city’s street runoff, including a lot of silt. At one time the city dredged the excess silt to keep the water clear; however, governments have been doing less of this lately, and the oxbows have been filling in with silt and vegetation. The built up banks, and spots of bare sandy soil are other reflections of past dredging. Most of the dead trees in this area are a result of beaver activity; at first the wire wrap held them off, but now they’ve learned to climb above the wire. Beaver tend to be a problem in these kinds of managed environments. There even used to be lots of trees along the Warren Avenue oxbow, but the beaver took them out about 10 years ago, and this has put back succession by about 50 years worth. Beavers along the oxbows tend to build bank dens rather than dams. Water birch, a native raparian species, is almost endangered now.
The final oxbow along this path (almost to Green Avenue) is beside a privately owned piece of land, and the owner has been taking very good care of it–this oxbow is generally in the condition that the Friends of the Oxbows would like to see all the oxbows in. Across the highway and beyond the channel, there are other oxbow areas which have been used most recently for cattle farming, but that is changing with the introduction of a new channel crossing and an upcoming shopping center.
We walked back to our parked cars and then drove to the foot of Brandon Avenue to see that oxbow from the other side. It is astonishing that only ten ago this was quite deep, open water; now it is very shallow and mostly filled with vegetation. However, just recently the City of Penticton has put in a silt interceptor on the drain at the foot of Brandon Avenue, and it is hoped that this will stop the silt build up.
On to the next oxbow access point, Figueras Mobile Home Park, where we enjoyed watching more ducks, including a wood duck, and also a muskrat. Our guide noted that there has been undercutting of the banks along the Mobile Homes due to the water; attempts have been made to stop it by putting in large cement “legos”; however, promoting more riparian growth would be more helpful.
Our next stop was behind the Oxbows RV Park, where for the first time we did not see any cat-tails; the water here is basic rather than acidic. Old pilings are part of the CPR waterway barges system when the oxbows were used for transportation. Rocks placed along the edges of the oxbow have created banks that unfortunately are too steep for good riparian growth.
Finally, we went out onto the highway where it enters Penticton, and took a quick look at where the Okanagan River used to flow into Skaha Lake–you can see it just east of where the channel enters the lake; it is the marshy area that crosses the beach there. We drove back north along the highway bypass, and parked near the north end of the channel by the recreational area there (just south of Loco Landing). This is what is left of the old Okanagan River at its northern end–bits of swampy ground surrounded by lawns and large, planted trees. Because it is so close to the channel, and there is no road in between, it could easily be connected to the channel to introduce fresh water and restore the natural riparian vegetation. Our guides showed us aerial photos of how the area looked before the channel was put in and the oxbows were cut off. Thanks to the Friends of the Penticton Oxbows for an amazing tour!