Metres per second, and why the shops quote Calgary
Calgary anglers talk about the Bow in cubic metres per second, usually shortened to cms, and they mean the water coming out of Bearspaw Dam and through the city. Bow River Troutfitters' reports give a working scale: 30 to 45 cms is a low winter or drought river, 55 cms in October is barely into the low end of normal, around 100 cms in August is well within the normal range, and just under 200 cms after runoff is when the water turns green again and the fishing looks good. Above that, in June, the river is high and silty and the day belongs to streamer anglers who can row. The Ideal Flow on this page, 2,100 to 7,000 cfs, is that 60 to 200 cms band converted.
The gauge used here sits below the Carseland Dam, at the downstream end of the popular water, so it usually reads a little higher than the Calgary number once the Highwood and the Elbow have come in and the irrigation canals have taken their share. ECCC's monthly means at Carseland run about 55 cms in January, 276 cms in June, 106 in August and 80 in September. On September 24, 2026 it read 88 cms, while the shops had been reporting roughly 65 cms in Calgary a couple of weeks earlier, below average for the date. The flows are regulated: TransAlta runs the Ghost and Bearspaw reservoirs upstream, and shop reports regularly mention it holding the river steady in summer or bumping it in spring.
Harvie Passage to the Carseland weir
Inside the city the river is walk-and-wade water along the Bow River pathway, with the Calgary Weir near downtown diverting water to the Western Irrigation District. The Harvie Passage, a series of built rapids that replaced the weir's deadly recirculating wave, was wrecked by the 2013 flood and rebuilt by 2021; boaters pass through it rather than over the old drop. Fish Creek Provincial Park on the south side of the city has a boat launch on the Bow and more than 100 kilometres of trails, and the flat, open river there is good spey water.
Below the city is the reason people fly in. Fish Tales Fly Shop describes 55 kilometres of nutrient-rich water between Calgary and the Carseland area, and Bow River Troutfitters says its guides float south of the city most days because the added nutrients below the treatment plants grow more insects and bigger trout. Sandstone cliffs and grassy undercut banks line a river cutting through flat farmland. Anglers know the float by its access points: Policeman's Flats on the edge of the city, near where the 570-hectare Ricardo Ranch subdivision is planned for the north bank, and McKinnon Flats, whose access road stays gated through winter; in 2024 the gate was set to open April 15. The float ends at the Carseland weir, where the Bow River Irrigation District takes its water; Wyndham-Carseland Provincial Park, 2 km east and 2 km south of Carseland on Highway 24, has a day-use area on the river with walking access year round. Big rainbows spawn up the Highwood in spring, so Fish Tales warns that fewer 19-inch-plus rainbows are in the main river in late April and May, and they drop back down on the June high water.
Stampede week belongs to the golden stones
Fish Tales and Bow River Troutfitters agree on the calendar. Midges and blue-winged olives carry the early season, with March Browns in May and the Mother's Day caddis toward the end of that month. Skwalas show up in April but, in Troutfitters' words, are not as prevalent on the Bow as on some other waters. Runoff peaks in June; the golden stone nymphs migrate to the banks over the last two weeks of the month, and the adult hatch peaks in the first two weeks of July, which usually lines up with the Calgary Stampede. Get on the water early: Troutfitters describes a minor arms race among guides to be the first boat down on foam bugs.
After the stones, caddis, PMDs and pale evening duns fill July evenings. August brings hoppers, crane flies and clouds of tricos that big fish sip at size 20. September, the busiest guiding month, is hopper-dropper water with olives returning and water boatmen showing up; Fish Tales swings a #14 to 16 Prince for the boatman fall. In late October and November the browns move up toward the city section to spawn, so give the redds a wide berth when you wade.
Zero trout, no bait, and the 2 p.m. rule
Alberta's 2026 Guide to Sportfishing Regulations lists the Bow from the Banff National Park boundary downstream to the Bassano Dam, including the reservoir, as open all year with a bait ban and a limit of 0 trout, 0 mountain whitefish, 0 pike, 0 walleye and 0 burbot. Everything is released. The same row covers the Highwood within 500 metres of its mouth. Only below the Bassano Dam does harvest return, with a May 8 to March 15 season and 2 trout. Bull trout are 0 everywhere in the province, and angling through the ice on flowing water in the ES1 to ES4 zones is not allowed.
Summer heat can shorten the day. When water temperatures pass 20 C for three or more days in a row, Alberta can impose time-of-day restrictions that close flowing waters in ES1, including the Bow from the park boundary to the Bassano Dam, from 2 p.m. to midnight. That happened in late August 2022. Bow River Troutfitters also stops guiding when water passes 68 F.
Above Canmore: the Bow under Parks Canada
Inside Banff National Park the provincial licence is not valid. You need a national park fishing permit and a park entry pass, and every fish, except lake trout from Lake Minnewanka, must be released where it was caught; Parks Canada adopted that after whirling disease turned up in Johnson Lake and the Bow in 2016. The Bow is open year round from Hector Lake to the east park boundary, with no ice fishing, while its tributaries other than the Cascade open only July 1 to August 31, 2026. The river from the Bow Lake outlet to Hector Lake is closed to all water activity.
The gear rules are stricter than below the park: no natural bait or scent, no lead sinkers, jigs, lures or flies under 50 grams, one fly per line, and no fishing from two hours after sunset to one hour before sunrise. Felt-soled boots are banned in every park water. Troutfitters is candid that mountain floats near Banff and Canmore produce fewer fish, and are booked for the setting more than the numbers.