By Medicine Hat News on March 1, 2019.
Marilou Montemayor and Maggie Romuld
Special to the News
People have always been attracted to stream banks and lake shores. While early explorers used rivers for transportation and commerce, or as valuable sources of water, modern outdoor enthusiasts are more likely to just want to relax in the shade of an edge-water forest or take in the beauty of a river valley landscape.
Both science and law refer to water-edged zones as “riparian,” and for planning or study purposes they have been formally defined as “relating to, or situated or dwelling on, the bank of a river or other body of water.” In their healthy natural state, these strips of land between the water and upland appear as green ribbons along streams, or oddly shaped rings around lakes or reservoirs. And in the semi-arid climate of southeastern Alberta, these bands of green contrast vividly with surrounding uplands, cropped fields, pastures, and coulees.
Plants grow along shorelines in direct response to their proximity to the edge of the water and its depth and duration. At the water’s edge, common plants include those that prefer constantly wet soil and standing water (for example cattails and bulrushes). Farther away from the water’s edge are plants that thrive in continually moist soil, but not in flooded conditions. These might include sedges and arctic rush, and some upland grasses. Farther yet from the shore are zones of woody shrubs and trees.
Riparian areas provide value above and beyond their aesthetic appeal. They provide food and habitat for a wide variety of creatures ranging from fish, frogs, mud dwellers and tiny organisms in water and bottom sediments; to birds, deer, moose and other wildlife. More importantly, they provide ecological services that benefit people. Vegetation, especially woody vegetation (shrubs and trees) provides a natural infrastructure which helps reduce the impact of rushing flood water by dissipating its energy. Plant roots hold the soil and streambanks and prevent erosion. In lakes, vegetation moderates the effects of high water levels and wave action. Riparian banks also store excess water during high water flow and gradually discharge it during low flow.
Unfortunately, when riparian areas are close to human settlements or subjected to human interference, they often suffer from overuse, which can lead to severe impacts. Degradation can result from constant trampling of vegetation, over-browsing of woody shrubs, soil compaction, or soil erosion by water and wind (often made worse by lack of plants). In pastures, trampling of vegetation is caused by livestock, and in urban areas, by pets and people. Riparian areas are also wholly lost to direct development and paved infrastructure.
The South East Alberta Watershed Alliance (SEAWA), in partnership with private landowners, City of Medicine Hat, and St. Mary River Irrigation District (SMRID), restored and enhanced 7.7 kilometres of riparian areas between May 2018 and January 2019. Projects included fencing to prevent livestock access and installing an off-stream livestock watering system, planting 1,000 native shrubs and trees, and removing a livestock corral panel from a riparian area. The projects were implemented in the City of Medicine Hat, Cypress County, and the County of Forty Mile; and were funded by the Recreational Fisheries Conservation and Partnerships Program (RFCPP), Fisheries and Oceans Canada, and the Watershed Resiliency and Restoration Program (WRRP), Government of Alberta.
There are well-established methods for the installation of fencing and off-stream watering equipment, and the removal of corral panels. However, the revegetation of degraded riparian areas was a challenge. There is no one-size-fits-all method for revegetating degraded riparian areas: each site is unique, and practices must be site-specific. Numerous factors needed to be considered when developing the 2018 revegetation methods and techniques: the semi-arid climate and a drought year; extreme heat warning and wind advisories; less snow than average; and warm spells in the fall and winter. It was also important to take into consideration soil characteristics; site slope and aspect (north, south, east, west); location on the inner versus outer curve of a stream; wildlife browsing; accessibility of the site to vehicles bringing supplies, tools and equipment; noxious and invasive weeds; and the availability of hired labour and volunteers.
Restoration methods and field techniques were developed by Marilou Montemayor, SEAWA’s executive director, who has a broad background in ecosystem restoration. Marilou was joined in the field by SEAWA staff Natasha Rogers, Brooklyn Neubeker, and Patrick Jablkowski; and the 2018 summer student Seline Solis. Sheldon Gill, Nickolas Grunwald, and Travis Auger were hired to help with restoration activities in the field. Garry Lentz, SEAWA’s chair, provided tools and storage space, supplied sandbar willow stakes, and helped maintain equipment.
Water influences riparian areas in three directions: flow from upstream to downstream (rivers and streams), horizontal flow from the water body to its bank, and shallow groundwater flow from below. The presence of plants and character of the soil also influence the dynamics of water in riparian areas. Therefore, the management of riparian areas requires a whole systems approach – one which considers the relationships between water in three directions, soil and sediment gain and loss, and vegetation.
Even a minor loss of riparian areas in southeastern Alberta results in significant ecological loss because riparian areas are few and far between in our semi-arid climate. Revegetation of degraded riparian areas is labour intensive and costly: sites must be prepared and planted, and there is time-consuming post-plant care (watering, weeding, mulching, browse protection, and replacing plants that did not survive). Post-plant care continues for several years until plants are established and plant roots have access to shallow groundwater. Therefore, it is best for our watershed, the overall environment, and the economy, to conserve and protect existing healthy riparian areas and prevent degradation from occurring.
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