Bighill Creek and its Watershed Plans
By Vivian Pharis, VP, BCPS
Bighill Creek’s Watershed and Early Planning
Bighill Creek’s 174 sqkm watershed begins as a classic fan, a gathering of slow waters from sprawling, open, cattle lands. There isn’t much water in the upper reaches of this basin. But, when the creek accepts a burst of pristine water from the nationally significant springs at Big Hill Springs Provincial Park, it becomes a bold flow. Below the park, the robust creek enters a narrower valley. Confined by a high sided coulee it descends to Cochrane and the Bow River, gliding past sandstone cliffs, some of which served ancient peoples as buffalo jumps, and slips past steep, forested slopes hiding deer and cougar. Interestingly, the coulee is a remnant of glacial times when impounded meltwaters broke free in a dramatic flood that carved a path to bedrock, in their escape to the Bow River.
In 2007 a tri-creeks watershed initiative was launched by the Town of Cochrane and Rocky View Council, to better understand the three waterways entering the Bow River at Cochrane. Bighill was the last of the three to inspire a group of people to begin planning. Bighill Creek Preservation Society was registered in 2015 and announced a Board of Directors, developed a mission statement, a set of six objectives and began work on four actions aimed at understanding and preserving the watershed.
BCPS begins stewardship work and watershed studies
One BCPS objective is to encourage stewardship, another is to educate about the natural and historic features of the valley. To these ends, BCPS accepted stewardship of a 40 acre RVC reserve in the creek’s bottom, most of it designated “environmental”. Trails through the reserve had suddenly been “discovered” by new Cochrane residents and heavy use began around 2015 – walking, dog walking, running and cycling. There was a sudden need to build a footbridge over the creek, to develop a loop trail, and begin diversions and rehabilitation on the steep, forested side where soils are thin and erodible.
A grant from the Cochrane Foundation allowed BCPS to buy three motion sensor cameras. These were set to work understanding wildlife use in the valley, but one was devoted to monitoring human trail use to enhance stewardship work. BCPS has also set up 7 sites along the trail that are measured and photographed each year for erosion, widening, deepening and root exposure. These will help guide our maintenance program.
Funds were raised in 2016, to begin collecting baseline data through studies towards a watershed plan. The first undertaking was to monitor the quality of stream water. A scientist, Dr. Ymene Fouli, was hired in 2017 to test waters at five sites on the creek and at two springs. These studies are to be repeated in 2019, with, hopefully, the addition of more sampling sites in the upper reaches of the basin.
Another set of funds allowed BCPS to commission a Riparian Health Assessment of the creek in the early summer of 2018. The expertise of Cows and Fish was hired to survey the creek for riparian cover, invasive plants, tree and shrub establishment, state of vegetation and human or livestock damage to stream banks. While provincial waterways score on average, 70% – healthy but with problems, Bighill Creek scored 87%, or generally healthy. We are in great shape, but it will take work to maintain this record in light of increasing recreational pressure on the creek.
The springs contributing most of the flow to Bighill Creek are nationally significant because of their constant year-around flow rate and temperature, as well as their uncommon tufa formations. Of great concern to BCPS are applications for three new gravel mines on the very aquifer of this unusual set of springs, and the lack of responsibility so far shown by Rocky View County for the springs and the provincial park they support. This situation has occupied much of BCPS’s efforts in the past two years.
This valley, so close to a town nearing 30,000 people, is surprisingly full of wildlife. Our cameras helped to show Bighill Creek as home to healthy populations of moose, white tail and mule deer, cougar, fox, coyote and beaver. Our blue heron colony has been hatching up to 8 nests of eggs continuously for at least 100 years. More rarely seen, but caught on camera were a bobcat and a racoon!!! Mink and muskrat are in the creek, along with chorus frogs, wood frogs, tiger salamanders and there used to be a good population of western toads. Garter snakes are abundant. In spring and summer the valley rings with bird calls. Red tailed hawks, horned owls and prairie falcons all nest and hunt in the valley.
A reason for the variety and numbers of wildlife in Bighill Valley is the proximity of the Bow River and the large Glenbow Park along the river. Right now, there is still enough undeveloped land between these two natural valleys to allow a free-flow of wildlife. The main barrier between them though is Highway 1A, with its reputation for killing more wildlife/km than any other highway in Alberta. Plans for vastly increasing residential development on both sides of the highway between Cochrane and Calgary, bode ill for maintaining wildlife numbers.
We are especially interested in fish populations and on a day in June, 2018, at 5 sites on the creek, Trout Unlimited, along with board member Ken Stevenson, caught and released 40-50 fish of a wide variety of species including trout (but not Cutthroat Trout), in the space of 12 minutes, in the lower reaches of the creek. Fish were found in all sites tested. Cochrane Environmental Action Committee has committed to buying temperature loggers that will be placed in the creek this winter/spring in order to better understand if the creek could again support endangered Cutthroat Trout.
Grant funds have been applied for to begin assessing beaver habitat throughout the creek. Funds are also being sought for the purchase of “pond levelers” or “beaver deceivers” to better control water levels in several downstream dams that have been flooding Ranch Road.
Reserve as Laboratory
The small natural reserve so close to Cochrane, is increasingly being seen as an outdoor laboratory for school groups. BCPS is also increasingly asked to talk about the creek and its ecology at Cochrane schools. To better understand the importance of natural areas, BCPS will begin studies of local insect populations on the reserve. Knowing that the world’s insect populations are disappearing at alarming rates, we consider it timely to learn about populations nearer home, and perhaps find out if ours are also in decline. This spring and summer will see a University of Calgary student assess the creek’s aquatic insects. A small grant from the Town of Cochrane has allowed BCPS to purchase two Malaise insect traps from California and these will be tested in the spring of 2019 to begin an educational investigation of terrestrial insects. Several schools have already indicated interest in being involved. Anyone with knowledge of how to undertake such studies is invited to help us.
Another buggy undertaking in the little reserve, is to see if we can naturally control invasive Canada Thistle. To this end, BCPS bought a packet of tiny thistle-eating weevils from Alberta Agriculture and released them in an infested area in 2018. Apparently it can take up to 4 years to see if there has been survival and results.