In this part of the world, as it no doubt does elsewhere, the natural order does its best to ensure survival of the various species. You will have noticed the changing of Oldman River colours from deep green awhile ago to muddy brown now. It may lighten a bit for a short time, depending on the weather. But, you can be certain there won’t be many days between now and early July, if things go as they often do, when the river will be considered anything but off.
Off is a term used by anglers to describe water that’s not really fishable, except for the very dedicated. But, that combined with some fishing regulations help minimize interference with fish spawning. Rainbow and Westslope Cutthroat Trout, for example. spawn this time of year -– generally May to July. They find gravelled-bottomed stretches of streams. Females swish their tails to clear a bed where they can drop their eggs for the males to fertilize. On days when the water’s clear and low, you can see the redds – they appear as cleaned gravel and are areas to be avoided by wading fishers.
But, that tends to be moot anyway, because few anglers want to wade in muddy water caused by spring runoff, which generally runs from early to mid-May in the Oldman drainage, and usually ends in early July. That’s when lakes are good places to take your pontoon boat and drop a nymph or water boatman for stocked rainbows. (Just don’t find yourself at the east end of the lake when a west wind is blowing and all you have is a paddle!)
Last year, runoff dragged on a little longer and this year, well, who knows: the snowpack that feeds the runoff is higher than normal – from 121 percent of average at South Racehorse Creek in the Upper Oldman to 229 percent at Lee Creek, a main St. Mary River tributary. The averages vary from 21 to 45 years, depending on how long recording stations have been active.
Of course, man’s engineering efforts, particularly damming rivers, most notably the Oldman, St. Mary and Waterton, can affect fish spawning downstream of the structures. Incubating eggs need a minimum flow, so dam operators have been asked to try to maintain that for the sake of spawning, as only one of their roles when they release water. They also need to maintain the integrity of the dam itself during times of high runoff as well as to maintain levels in the reservoirs to release later when it’s needed for irrigation. Other organisms, such as cottonwood trees native to our river valleys, also require a constant water flow later in the year to assure their survival.
In the headwaters, the OWC’s Headwaters Action Plan has as one of its objectives completing a fine scale cumulative effects assessment of fish populations and habitat streams. The Partnership Advisory Network participants that helped craft the HAP generally accepted the findings of the Alberta Westslope Trout Recovery Plan which, among other conclusions noted, as an example, the effect of sediment from runoff along logging roads on Cutthroat and Bull Trout spawning areas. The next step is to determine what can be done about it to protect redds.
So, in the grand design, it should all work together, sometimes with man’s help and sometimes to encourage man to tread more softly on a delicate ecosystem.